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Sample records for deposit western sichuan

  1. Development of foreland basins around western Sichuan basin, and implications for mountain building in eastern Tibet

    NASA Astrophysics Data System (ADS)

    Chen, S.; Liu, M.

    2014-12-01

    The Sichuan basin is surrounded by the Tibetan Plateau to the west, and the Michang Shan and Daba Shan mountains to the north and northwest. Foreland basins have been developed along the western and northern margins of the Sichuan basin since Triassic, receiving sediments with significant along-strike variations. These sediment records provide useful insights into the history of mountain building around the Sichuan Basin. We have collected exploration well data from western Sichuan Basin. Using backstripping, we reconstructed the basement deformation history, which reflect sedimentary and tectonic loadings related to mountain building. We used a 3-D numerical modeling technique with multi-grid technique to simulate flexural deformation of the Sichuan Basin lithosphere, and to infer tectonic loading and mountain building along western and northern margins of the Sichuan Basin from the late Triassic to the Cenozoic. Our results suggest that the shortening of the Daba Shan and Michuan Shan orogens mainly occurred during the late Jurassic-Cretaceous. During Cenozoic, the tectonic loading mainly occurred along the southwestern margins of the Sichuan Basin, corresponding to the development of the Longmen Shan mountain belt. The tectonic loading of the northern Longmen Shan on the Sichuan Basin has been markedly reduced since the Cenozoic, evidenced by the lack of Cenozoic foreland basin development. This indicates mechanical decoupling between uplift of the Tibetan Plateau and the Sichuan Basin, consistent with the deep down-cutting of the Longmen Shan fault and predominantly strike-slip motion on the fault. The limited Cenozoic foreland basin development in the southwestern margin of the Sichuan Basin is consistent with localized high-angle thrusting of the southern Longmen Shan mountains. This work was supported by the National Natural Science Foundation of China (grants 41104046).

  2. Lunar western limb pyroclastic deposits

    NASA Technical Reports Server (NTRS)

    Coombs, Cassandra R.; Hawke, B. Ray

    1991-01-01

    It has become increasingly evident that the lunar pyroclastic volcanism played an important role in the formation and resurfacing of many areas of the Moon. On-going analysis of lunar Orbiter and Apollo photographs continues to locate and identify pyroclastic deposits and suggests that they just may be more ubiquitous than once thought. Located near mare/highland boundaries, many of these deposits formed contemporaneously with effusive mare volcanism. The mantling deposits formed as products of fire-fountaining. Probable source vents for these deposits include irregular depressions at the head of associated sinuous rilles and/or along irregular fractures in the floors of ancient craters. Here, researchers provide a brief synopsis of the nature of the dark mantling deposits and briefly discuss several newly identified deposits on the western limb.

  3. Black carbon record of the wildfire history of western Sichuan Province in China over the last 12.8 ka

    NASA Astrophysics Data System (ADS)

    Sun, Weiwei; Zhang, Enlou; Shen, Ji; Chen, Rong; Liu, Enfeng

    2016-01-01

    Wildfire is recognized as a critical Earth system process which affects the global carbon cycle, atmospheric chemistry, and ecosystem dynamics. Estimating the potential impact of future climate change on the incidence of fire requires an understanding of the long-term interactions of fire, climate, vegetation, and human activity. Accordingly, we analyzed the black carbon content and the pollen stratigraphy of sediments spanning the past 12.8 ka from Lake Muge Co, an alpine lake in western Sichuan Province, in order to determine the main factors influencing regional fire regimes. The results demonstrate that wildfires occurred frequently and intensively during the late deglaciation and the early Holocene when the regional vegetation was dominated by deciduous forests. Wildfire occurrence decreased significantly during the Holocene climatic optimum between 9.2 and 5.6 cal ka BP. Overall, the wildfire history of western Sichuan Province is similar to that of the Chinese Loess Plateau and of East Asia as a whole, suggesting that regional-scale fires depended mainly on changes in the intensity of the Asian summer monsoon. In addition, the fire regime of western Sichuan Province may have been influenced by the establishment of human settlement and agriculture in western Sichuan Province and the southeastern Tibetan Plateau after about 5.5 cal ka BP, and by an intensification of cereal cultivation coupled with population expansion in southwestern China during the last two millennia.

  4. Genetic Structure of Qiangic Populations Residing in the Western Sichuan Corridor

    PubMed Central

    Wang, Chuan-Chao; Wang, Ling-Xiang; Shrestha, Rukesh; Zhang, Manfei; Huang, Xiu-Yuan; Hu, Kang; Jin, Li; Li, Hui

    2014-01-01

    The Qiangic languages in western Sichuan (WSC) are believed to be the oldest branch of the Sino-Tibetan linguistic family, and therefore, all Sino-Tibetan populations might have originated in WSC. However, very few genetic investigations have been done on Qiangic populations and no genetic evidences for the origin of Sino-Tibetan populations have been provided. By using the informative Y chromosome and mitochondrial DNA (mtDNA) markers, we analyzed the genetic structure of Qiangic populations. Our results revealed a predominantly Northern Asian-specific component in Qiangic populations, especially in maternal lineages. The Qiangic populations are an admixture of the northward migrations of East Asian initial settlers with Y chromosome haplogroup D (D1-M15 and the later originated D3a-P47) in the late Paleolithic age, and the southward Di-Qiang people with dominant haplogroup O3a2c1*-M134 and O3a2c1a-M117 in the Neolithic Age. PMID:25090432

  5. Genetic structure of Qiangic populations residing in the western Sichuan corridor.

    PubMed

    Wang, Chuan-Chao; Wang, Ling-Xiang; Shrestha, Rukesh; Zhang, Manfei; Huang, Xiu-Yuan; Hu, Kang; Jin, Li; Li, Hui

    2014-01-01

    The Qiangic languages in western Sichuan (WSC) are believed to be the oldest branch of the Sino-Tibetan linguistic family, and therefore, all Sino-Tibetan populations might have originated in WSC. However, very few genetic investigations have been done on Qiangic populations and no genetic evidences for the origin of Sino-Tibetan populations have been provided. By using the informative Y chromosome and mitochondrial DNA (mtDNA) markers, we analyzed the genetic structure of Qiangic populations. Our results revealed a predominantly Northern Asian-specific component in Qiangic populations, especially in maternal lineages. The Qiangic populations are an admixture of the northward migrations of East Asian initial settlers with Y chromosome haplogroup D (D1-M15 and the later originated D3a-P47) in the late Paleolithic age, and the southward Di-Qiang people with dominant haplogroup O3a2c1*-M134 and O3a2c1a-M117 in the Neolithic Age. PMID:25090432

  6. The anomalous lithium isotopic signature of Himalayan collisional zone carbonatites in western Sichuan, SW China: Enriched mantle source and petrogenesis

    NASA Astrophysics Data System (ADS)

    Tian, Shihong; Hou, Zengqian; Su, Aina; Qiu, Lin; Mo, Xuanxue; Hou, Kejun; Zhao, Yue; Hu, Wenjie; Yang, Zhusen

    2015-06-01

    Lithium concentrations and isotopic compositions of 38 carbonatites and associated syenites from the Maoniuping, Lizhuang, and Dalucao in western Sichuan, along with previously published and new Pb-Sr-Nd-C-O isotope data and whole-rock analyses, are used to constrain their mantle source and genesis. Carbonatites and syenites are characterized by extremely varying Li concentrations (0.8-120 ppm) and highly variable Li isotopic compositions (-4.5‰ to +10.8‰). Among them, the majority of the carbonatites and syenites have δ7Li values between +0.2‰ and +5.8‰, which overlap with the reported values for MORB and OIB; 3 carbonatites have higher δ7Li values between +8.7‰ and +10.8‰; 5 carbonatites and 4 syenites have lighter δ7Li values between -4.5‰ and -0.3‰. These highly variable δ7Li compositions could not have been produced by diffusive-driven isotopic fractionation of Li and thus may record the isotopic signature of the late Proterozoic subcontinental lithospheric mantle (SCLM). This paper demonstrates the existence of anomalous δ7Li within the late Proterozoic subcontinental lithospheric mantle, suggesting that the ancient SCLM beneath western Sichuan was modified by interaction with fluids derived from the subducted oceanic crust and marine sediments. The modeling curves of fluids derived from a dehydrated slab (ratios: AOC80-SED20 to AOC40-SED60) with a representative mantle composition can account for the majority of lithium compositional variations. Some samples with unusual Pb-Sr-Nd-O isotopic compositions and highly variable δ7Li compositions are affected by significant involvement of marine sediments in their source region, not contaminated by crustal materials. The carbonatites and syenites in western Sichuan were generated by the partial melting of subcontinental lithospheric mantle, which was metasomatized by the Li-rich fluids derived from the subducted oceanic crust and marine sediments. This melting was most likely triggered by a

  7. Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China

    USGS Publications Warehouse

    Fan, Delian; Hein, James R.; Ye, Jie

    1999-01-01

    The Jiaodingshan Mn-Co and Dawashan Mn deposits are located in the approximately 2-m thick Daduhe unit of the Wufengian strata of Late Ordovician (Ashgill) age. Paleogeographic reconstruction places the deposits at the time of their formation in a gulf between Chengdu submarine rise and the Kangdian continent. The Jiaodingshan and Dawashan deposits occur in algal-reef facies, the former in an atoll-like structure and the latter in a pinnacle reef. Ores are mainly composed of rhodochrosite, kutnahorite, hausmannite, braunite, manganosite, and bementite. Dark red, yellowish-pink, brown, green-gray, and black ores are massive, banded, laminated, spheroidal, and cryptalgal (oncolite, stromatolite, algal filaments) boundstones. Blue, green, and red algal fossils show in situ growth positions. Samples of high-grade Jiaodingshan and Dawashan ores assay as much as 66.7% MnO. Jiaodingshan Mn carbonate ores have mean contents of Ba, Co, and Pb somewhat higher than in Dawashan ores. Cobalt is widely distributed and strongly enriched in all rock types as compared to its crustal mean content. Cobalt is correlated with Cu, Ni, and MgO in both deposits and additionally with Ba and Zn in the Dawashan deposit. The δ13C(PDB) values of Mn carbonate ores (-7.8 to -16.3‰) indicate contributions of carbon from both seawater bicarbonate and the bacterial degradation of organic matter, the latter being 33% to 68%, assuming about -24‰ for the δ13C(PDB) of the organic matter. Host limestones derived carbon predominantly from seawater bicarbonate δ1313C(PDB) of +0.2 to -7‰). NW-trending fault zones controlled development of lithofacies, whereas NE-trending fault zones provided pathways for movement of fluids. The source of Co, Ni, and Cu was mainly from weathering of mafic and ultramafic rocks on the Kangdian continent, whereas contemporaneous volcanic eruptions were of secondary importance. The reefs were likely mineralized during early diagenesis under shallow burial. The reefs

  8. Mineral dust deposition in Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Bergmatti, Gilles; Losno, Rémi; Bon Nguyen, Elisabeth; Chevaillier, Servanne; Roulet, Pierre; Sauvage, Stéphane; Coddeville, Patrice; Ouboulmane, Noura; Siour, Guillaume; Tovar Sanchez, Antonio; Massanet, Ana; Morales Baquero, Rafael; Di Sarra, Giogio; Sferlazzo, Damiano; Dulac, François; Fornier, Michel; Coursier, Cyril

    2014-05-01

    North African deserts are the world's largest sources of atmospheric mineral dust produced by aeolian erosion. Saharan dust is frequently transported toward Europe over the Mediterranean basin. When deposited in oceanic areas, mineral dust can constitute a key input of nutrients bioavailable for the oceanic biosphere. For instance, Saharan dust deposited in the in the Mediterranean Sea can be a significant source of nutrient like Fe, P and N during summer and autumn. Our objective is to study the deposition Saharan mineral dust in the western Mediterranean basin and to improve how deposition processes are parameterized in 3D regional models. To quantify the deposition flux of Saharan dust in the western Mediterranean region a specific collector (CARAGA) to sample automatically the insoluble atmospheric particle deposition was developed (LISA-ICARE) and a network of CARAGA collectors have been set up. Since 2011, eight CARAGA are then deployed in Frioul, Casset, Montandon and Ersa in France, Mallorca and Granada in Spain, Lampedusa in Italia, and Medenine in Tunisia, along a South-North gradient of almost 2000km from the North African coast to the South of Europe. We observe 10 well identified dust Saharan deposition events at Lampedusa and 6 at Mallorca for a 1-yr sampling period. These dust events are sporadic and the South-North gradient of deposition intensity and frequency is observed (the highest dust mass sampled at the stations are : 2,66 g.m-2 at Lampedusa ; 0,54 g.m-2 at Majorque ; 0,33 g.m-2 at Frioul ; 0,16 g.m-2 at Casset). The ability of the CHIMERE model to reproduce the deposition measurements is tested. The mineral dust plumes simulated over the western Mediterranean basin are also compared to satellite observations (OMI, MODIS) and in-situ measurements performed during the ChArMEx campaign and in the AERONET stations.

  9. Hydrochemistry of the hot springs in western Sichuan province related to the Wenchuan MS 8.0 earthquake.

    PubMed

    Chen, Zhi; Du, Jianguo; Zhou, Xiaocheng; Yi, Li; Liu, Lei; Xie, Chao; Cui, Yueju; Li, Ying

    2014-01-01

    Hydrogeochemistry of 32 hot springs in the western Sichuan Province after the Wenchuan MS 8.0 earthquake was investigated by analyzing the concentrations of cation and anion and the isotopic compositions of hydrogen and oxygen. The water samples of the hot springs were collected four times from June 2008 to April 2010. Hydrogeochemical data indicated the water samples can be classified into 9 chemical types. Values of δ D and δ(18)O indicated that the spring waters were mainly derived from meteoric precipitation and affected by water-rock interaction and mixture of deep fluids. Concentrations of K(+)and SO4(-) of the samples from the Kangding district exhibited evident increases before the Wenchuan earthquake, indicating more supplement of deep fluids under the increase of tectonic stress. The chemical and isotopic variations of the water samples from the area closer to the epicenter area can be attributed to variation of regional stress field when the aftershock activities became weak. PMID:24892106

  10. Hydrochemistry of the Hot Springs in Western Sichuan Province Related to the Wenchuan MS 8.0 Earthquake

    PubMed Central

    Chen, Zhi; Zhou, Xiaocheng; Yi, Li; Liu, Lei; Xie, Chao; Cui, Yueju; Li, Ying

    2014-01-01

    Hydrogeochemistry of 32 hot springs in the western Sichuan Province after the Wenchuan MS 8.0 earthquake was investigated by analyzing the concentrations of cation and anion and the isotopic compositions of hydrogen and oxygen. The water samples of the hot springs were collected four times from June 2008 to April 2010. Hydrogeochemical data indicated the water samples can be classified into 9 chemical types. Values of δD and δ18O indicated that the spring waters were mainly derived from meteoric precipitation and affected by water-rock interaction and mixture of deep fluids. Concentrations of K+and SO4− of the samples from the Kangding district exhibited evident increases before the Wenchuan earthquake, indicating more supplement of deep fluids under the increase of tectonic stress. The chemical and isotopic variations of the water samples from the area closer to the epicenter area can be attributed to variation of regional stress field when the aftershock activities became weak. PMID:24892106

  11. [Relationships between decomposition rate of leaf litter and initial quality across the alpine timberline ecotone in Western Sichuan, China].

    PubMed

    Yang, Lin; Deng, Chang-chun; Chen Ya-mei; He, Run-lian; Zhang, Jian; Liu, Yang

    2015-12-01

    The relationships between litter decomposition rate and their initial quality of 14 representative plants in the alpine forest ecotone of western Sichuan were investigated in this paper. The decomposition rate k of the litter ranged from 0.16 to 1.70. Woody leaf litter and moss litter decomposed much slower, and shrubby litter decomposed a little faster. Then, herbaceous litters decomposed fastest among all plant forms. There were significant linear regression relationships between the litter decomposition rate and the N content, lignin content, phenolics content, C/N, C/P and lignin/N. Lignin/N and hemicellulose content could explain 78.4% variation of the litter decomposition rate (k) by path analysis. The lignin/N could explain 69.5% variation of k alone, and the direct path coefficient of lignin/N on k was -0.913. Principal component analysis (PCA) showed that the contribution rate of the first sort axis to k and the decomposition time (t) reached 99.2%. Significant positive correlations existed between lignin/N, lignin content, C/N, C/P and the first sort axis, and the closest relationship existed between lignin/N and the first sort axis (r = 0.923). Lignin/N was the key quality factor affecting plant litter decomposition rate across the alpine timberline ecotone, with the higher the initial lignin/N, the lower the decomposition rate of leaf litter. PMID:27111995

  12. [Response of Picea purpurea and Abies faxoniana tree rings at different slope aspects to rapid warming in western Sichuan, China].

    PubMed

    Guo, Bin-de; Zhang, Yuan-dong; Wang, Xiao-chun

    2016-02-01

    results of multivariate analysis of variance indicated that the combined effects of slope aspect, temperature and precipitation factors were the most important limited factors for tree growth variability in western Sichuan. Therefore, we should consider the combined effects of temperature, precipitation and different slope aspects when simulating and predicting tree-growth response to the recent climate warming trend. PMID:27396105

  13. [Difference in responses of major tree species growth to climate in the Miyaluo Mountains, western Sichuan, China].

    PubMed

    Guo, Ming-ming; Zhang, Yuan-dong; Wang, Xiao-chun; Liu, Shi-rong

    2015-08-01

    To explore the responses of different tree species growth to climate change in the semi-humid region of the eastern Tibetan Plateau, we investigated climate-growth relationships of Tsuga chinensis, Abies faxoniana, Picea purpurea at an altitude of 3000 m (low altitude) and A. faxoniana and Larix mastersiana at an altitude of 4000 m (high altitude) using tree ring-width chronologies (total of 182 cores) developed from Miyaluo, western Sichuan, China. Five residual chronologies were developed from the cross-dated ring width series using the program ARSTAN, and the relationships between monthly climate variables and tree-ring index were analyzed. Results showed that the chronologies of trees at low altitudes were negatively correlated with air temperature but positively with precipitation in April and May. This indicated that drought stress limited tree growth at low altitude, but different tree species showed significant variations. T. chinensis was most severely affected by drought stress, followed by A. faxoniana and P. purpurea. Trees at high altitude were mainly affected by growing season temperature. Tree-ring index of A. faxoniana was positively correlated with monthly minimum temperature in February and July of the current year and monthly maximum temperature in October of the previous year. Radial growth of L. mastersiana was positively correlated with monthly maximum temperature in May, and negatively with monthly mean temperature in February and monthly minimum temperature in March. In recent decadal years, the climate in northeast Tibetan Plateau had a warming and drying trend. If this trend continues, we could deduce that P. purpurea should grow faster than T. chinensis and A. faxoniana at low altitudes, while A. faxoniana would benefit more from global warming at high altitudes. PMID:26685584

  14. Mercury deposits of western California: an overview

    NASA Astrophysics Data System (ADS)

    Studemeister, P. A.

    1984-07-01

    Mercury deposits in western California are near a thrust fault that separates two groups of Mesozoic rocks. The Franciscan Assemblage, a metamorphosed melange with serpentine and graywacke, is structurally overlain by the Great Valley Sequence, a sedimentary series resting on oceanic crust. These Mesozoic rocks are partly covered by volcanic and sedimentary rocks of Cenozoic age. Cinnabar with silica minerals, dolomite, native mercury, and bituminous matter occurs around the fractured margins of serpentine bodies and around hot springs that emanate from the Franciscan Assemblage. Fluid inclusions and hot springs suggest that cinnabar precipitated from CO2-H2O fluids with <2 wt% chlorine at T<250 °C. Prograde metamorphism of Mesozoic sediments expulsed mercury-bearing fluids that migrated up serpentine-related fractures and exhaled onto the surface.

  15. Provenance and tectonic-paleogeographic evolution: Constraints from detrital zircon U-Pb ages of Late Triassic-Early Jurassic deposits in the northern Sichuan basin, central China

    NASA Astrophysics Data System (ADS)

    Shao, Tongbin; Cheng, Nanfei; Song, Maoshuang

    2016-09-01

    U-Pb ages of 290 new detrital zircons from five Late Triassic-Early Jurassic sandstone samples in the northern Sichuan basin, along with other geological data, are used to constrain the sediment provenance and evaluate tectonic-paleogeographic evolution for the adjacent orogens through/from which these sediments were potentially derived. The Upper Triassic depocenter was located at the front of the Longmen Shan belt, and sediments in the western, southern and eastern Sichuan basin shared the southern North China block (NCB) and Qinling belt with the eastern Songpan-Ganzi terrane of Middle-Upper Triassic via the Longmen Shan belt, whereas the northern part of the basin was fed by dominant South Qinling belt (SQB) and northern Yangtze block and possibly subordinate southern NCB. Also, the youngest population in the northern Sichuan basin has a slightly younger age peak (∼235 Ma) than those (∼270 Ma) in other parts of the basin. During the Early Jurassic, the depocenter was still at the front of the Longmen Shan belt but only northern regions (e.g., SQB and northern Yangtze block) fed the basin. The northern Sichuan basin received less sediments from the southern NCB and more from the SQB and northern Yangtze block during the Early Jurassic than during the Late Triassic. The middle Mesoproterozoic detrital zircons, which likely originated from the North Qinling belt and northern Yangtze block where rocks with these zircons may be unexposed, occur more widely in the Lower Jurassic than in the Upper Triassic. These facts suggest that from the Late Triassic to Early Jurassic, it was increasingly difficult for sediments to transport from the NCB into the northern Sichuan basin and the provenance transferred progressively from the southern NCB to both the SQB and northern Yangtze block, implying the continuous South China block-NCB collision during that time.

  16. Tree ring-based temperature reconstruction over the past 186 years for the Miyaluo Natural Reserve, western Sichuan Province of China

    NASA Astrophysics Data System (ADS)

    Li, Zong Shan; Liu, Guo Hua; Gong, Li; Wang, Meng; Wang, Xiao Chun

    2015-05-01

    The mountain range of western Sichuan Province of China runs roughly north to south defining the eastern edge of the Tibetan Plateau, where high-resolution climate records are essential for understanding regional climatic phenomena. Unfortunately, instrumental records in this region are too short in duration to confidently gauge the long-term variability of climate change. This paper presented a temperature reconstruction for the western Sichuan Province based on a tree ring width chronology developed from a tree line site (4,150 m) of the Faxon fir ( Abies faxoniana) at the Miyaluo Natural Reserve. This reconstruction, spanning the years from 1824 to 2009, could account for 46.7 % of the actual variance of annual mean temperature during the calibration period from 1950 to 2002. The reconstruction could be essentially divided into two distinct subperiods: a relatively cold and stable period in the late nineteenth century and a relatively warm and unstable period in the twentieth century. Years 2001 and 1911 were the warmest (6.32 °C) and coldest (4.87 °C) years in the reconstruction, respectively, while 1960s (5.77 °C) and 1980s (5.08 °C) were the warmest and coldest ten consecutive years within the past 186 years. Close coupling observed with other temperature proxies (tree rings, ice cores, and glaciers) from surrounding areas emphasized the high degree of confidence in our reconstruction.

  17. ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION IN THE WESTERN UNITED STATES

    EPA Science Inventory

    Article synthesizes existing studies (biological, ecological, biogeochemical) on the effects of nitrogen deposition to aquatic and terrestrial ecosystems in the western United States. In the western U.S, vast acreages of land are exposed to low levels of atmospheric deposition, w...

  18. NITROGEN EMISSIONS, DEPOSITION, AND MONITORING IN THE WESTERN UNITED STATES

    EPA Science Inventory

    Article presents new summary of existing data on nitrogen emissions and deposition in the western region of the United States. Study finds that nitrogen emissions and deposition have increased in the western US due to raid increases in urbanization, population, vehicle miles trav...

  19. Paleogene depositional framework of western Transverse ranges

    SciTech Connect

    Dickinson, W.R.

    1988-03-01

    In the western Transverse Ranges, widespread Paleogene sequences (mid-Paleocene to mid-Oligocene) accumulated to thicknesses locally in excess of 5000 m. The Paleogene basin occupied a complex forearc setting located near the offshore Franciscan trench, but distant from the inland Laramide orogenic system, where magmatism was quiescent during the interval of most rapid sedimentation. The pre-Tertiary substratum, largely masked by its Paleogene cover, was probably disrupted by transpressional and/or transtensional tectonics associated with separate episodes of mid-Cretaceous sinistral and Late Cretaceous (to Paleocene.) dextral dislocation of the continental margin. Paleogene strata include diachronous facies of intertonguing deep-marine, shallow-marine, marginal-marine, and nonmarine clastic strata representing varied depositional systems. Turbidite assemblages include both progradational and retrogradational phases of canyon-fed submarine fans and delta-fed submarine ramps. Exposed shelf-break successions were deposited offshore from strandline complexes fringing delta margins and broad coastal plains. Sparse but diagnostic nonclastic facies include local algal carbonate edifices built on isolated submarine banks, and minor lagoonal beds of algal carbonates and gypsiferous evaporites associated with emergent delta platforms. The complex Paleogene forearc basin was flanked on the northeast by Salinian basement rocks and on the southwest by a tectonic ridge of subduction complex uplifted along the Paleogene trench-slope break. The present geographic distribution of Paleogene facies tracts is fully compatible with proposed Neogene tectonic rotations of panel-like basin segments, bounded by antithetic sinistral faults within the dextral San Andreas system, as detected by recent paleomagetic investigations.

  20. Atmospheric wet deposition of sulfur and nitrogen in Jiuzhaigou National Nature Reserve, Sichuan Province, China.

    PubMed

    Qiao, Xue; Xiao, Weiyang; Jaffe, Daniel; Kota, Sri Harsha; Ying, Qi; Tang, Ya

    2015-04-01

    In the last two decades, remarkable ecological changes have been observed in Jiuzhaigou National Nature Reserve (JNNR). Some of these changes might be related to excessive deposition of sulfur (S) and nitrogen (N), but the relationship has not been quantified due to lack of monitoring data, particularly S and N deposition data. In this study, we investigated the concentrations, fluxes, and sources of S and N wet deposition in JNNR from April 2010 to May 2011. The results show that SO4(2-), NO3-, and NH4+ concentrations in the wet deposition were 39.4-170.5, 6.2-34.8, and 0.2-61.2 μeq L(-1), with annual Volume-Weighted Mean (VWM) concentrations of 70.5, 12.7, and 13.4 μeq L(-1), respectively. Annual wet deposition fluxes of SO4(2-), NO3-, and NH4+ were 8.06, 1.29, and 1.39 kg S(N)ha(-1), respectively, accounting for about 90% of annual atmospheric inputs of these species at the monitoring site. The results of Positive Matrix Factorization (PMF) analysis show that fossil fuel combustion, agriculture, and aged sea salt contributed to 99% and 83% of annual wet deposition fluxes of SO4(2-) and NO3-, respectively. Agriculture alone contributed to 89% of annual wet deposition flux of NH4+. Although wet deposition in JNNR was polluted by anthropogenic acids, the acidity was largely neutralized by the Ca2+ from crust and 81% of wet deposition samples had a pH higher than 6.00. However, acid rain mainly caused by SO4(2-) continued to occur in the wet season, when ambient alkaline dust concentration was lower. Since anthropogenic emissions have elevated S and N deposition and caused acid rain in JNNR, further studies are needed to better quantify the regional sources and ecological effects of S and N deposition for JNNR. PMID:25525712

  1. Pyroclastic deposits on the western limb of the moon

    NASA Technical Reports Server (NTRS)

    Coombs, Cassandra R.; Hawke, B. R.

    1992-01-01

    A geologic characterization is presented of 17 newly identified localized pyroclastic deposits on the western limb of the moon. The results show that lunar pyroclastic deposits are more pervasive on the western limb of the moon than once thought. The western limb dark-mantle deposits in the proximal zone are probably related to faults and fractures associated with the Cordillera ring of Orientale Basin. All the localized pyroclastic deposits on the western limb for which near-infrared reflectance spectra have been obtained exhibit parameter that allowed them to be assigned to the three spectral groups described elsewhere. Western limb pyroclastic deposits appear to represent various stages in a formational sequence in which an initial explosive phase is followed by varying amounts of mare flooding. In view of their sequential formation, both the pyroclastic and mare materials associated with individual volcanic complexes may be the products of the same parent magmas and have very similar compositions.

  2. Permian to Late Triassic evolution of the Longmen Shan Foreland Basin (Western Sichuan): Model results from both the lithospheric extension and flexure

    NASA Astrophysics Data System (ADS)

    He, Lijuan

    2014-10-01

    The lithosphere was extended during the Permian-Middle Triassic in the Yangtze Craton where the Sichuan Basin located, and then bent due to thrusting of the Longmen Shan orogen, leading to formation of the Longmen Shan Foreland Basin (Western Sichuan) during the Late Triassic Indosinian orogeny. The lateral variation of the lithospheric strength resulted by former differential extension would inevitably influence the subsequent evolution of the foreland basin. In order to investigate this, both extensional and flexural models were applied in modeling Permian-Late Triassic basin evolution. A 2D kinematic extensional model was initially developed along a profile crossing the Yangtze Craton to simulate the lithospheric thermal evolution during the Permian-Middle Triassic. Based on the thermal results, the thermal-rheological structure, as well as the effective elastic thickness of the lithosphere (Te), was then determined. Extension model show that the stretching factors decrease gradually from Songpan-Ganzi to the Sichuan Basin, leading to variable thermal-rheological structure and increased Te from west to east. Taking into account of the Te variation, a flexural model was finally constructed to investigate the evolution of the Longmen Shan Foreland Basin during the Late Triassic spanning the time period c. 227-206 Ma. Three episodes were divided according to the corresponding tectonostratigraphic units. By matching the stratigraphic observations, three phase advance distances eastward of the Longmen Shan along the Qingchuan-Maowen Fault turned out to be 18, 22, and 18 km. It implied a slow and similar thrust advance rate of 3.6 (c.227-222 Ma), 2.2 (c.222-212 Ma), and 3 mm/yr (c.212-206 Ma), respectively.

  3. Freshwater diatomite deposits in the western United States

    USGS Publications Warehouse

    Wallace, Alan R.; Frank, David G.; Founie, Alan

    2006-01-01

    Freshwater diatomite deposits in the Western United States are found in lake beds that formed millions of years ago. These diatom-rich sediments are among the Nation's largest commercial diatomite deposits. Each deposit contains billions of tiny diatom skeletons, which are widely used for filtration, absorption, and abrasives. New studies by the U.S. Geological Survey (USGS) are revealing how ancient lakes in the Western States produced such large numbers of diatoms. These findings can be used by both land-use managers and mining companies to better evaluate diatomite resources in the region.

  4. The effects of China's environmental protection policies on pasture quality and the activities of small-scale herders in Songpan County, Western Sichuan.

    PubMed

    Veeck, Gregory; Li, Zhou; Yu, Fawen; Emerson, Charles

    2015-06-01

    Since 2000, there has been an ambitious governmental effort to protect China's grassland resources through new, often controversial, policies and programs backed up by massive capital investments and subsidies. The policies are intended to protect pastoral ecological systems while allowing the pasture-based husbandry sector to continue to evolve in ways that assure acceptable revenues to affected families and regions. This article reports results of a case study conducted in Songpan County of western Sichuan during the fall of 2013 specifically focused on these issues and interactions. The mixed-method research combines remotely sensed MODIS vegetation indices (EVI), livestock counts by type, and grassland area estimates at the township scale from 2000-2012, with depth interviews with local herding families and husbandry officials to determine how the husbandry sector has changed in the past 12 years under post-2000 policy interventions. Results for Songpan indicate that pasture coverage has improved slightly as grazing livestock density per hectare declined, but herders and local officials report that some of the new laws and programs have important unanticipated negative impacts on pasture quality, pasture ecology, and economic returns from herding for some families. PMID:25995138

  5. [Seasonal dynamics of soil labile nitrogen pools and net nitrogen mineralization in subalpine forests along an elevational gradient in western Sichuan, China].

    PubMed

    Yin, Rui; Xu, Zhen-Feng; Wu, Fu-Zhong; Yang, Wan-Qin; Xiong, Li; Xiao, Sa; Ma, Zhi-Liang; Li, Zhi-Ping

    2013-12-01

    The seasonal dynamics of soil labile nitrogen pools and net nitrogen mineralization of three subalpine forests along an elevation gradient (3600, 3300 and 3000 m), western Sichuan, China were examined. Obvious seasonal dynamics were found in soil labile nitrogen pools (ammonium, nitrate, microbial biomass nitrogen and dissolved organic nitrogen) and net nitrogen mineralization rate, but the seasonality varied with the measured nitrogen pools. The concentrations of soil nitrate (8.38-89.60 mg x kg(-1)) were significantly higher than those of ammonium (0.44-8.43 mg x kg(-1)) in four sampling periods (non-growing season, early, middle and late growing season). Regardless of the elevation, the rate of soil net nitrogen mineralization was negative (-0.77 to -0.56 mg x kg(-1) x d(-1)) early in the growing season, but positive in the other three periods. Except for nitrate, the contents of ammonium, microbial biomass nitrogen and dissolved organic nitrogen varied significantly with elevation and the altitude effects on those pools were dependent on seasons. In summary, soil nitrification was the major process of net soil nitrogen mineralization and soil nitrogen mineralization was not affected by elevational gradient. Soil nitrogen mineralization (0.42-0.99 mg x kg(-1) x d(-1)) in winter was considerable in this area. Relatively high inorganic nitrogen in early spring might be favorable for vegetation growth, but might also be lost from soil ecosystem through leaching. PMID:24697050

  6. [Litter decomposition and lignocellulose enzyme activities of Actinothuidium hookeri and Cys- topteris montana in alpine timberline ecotone of western Sichuan, China].

    PubMed

    Chen, Ya-mei; He, Run-lian; Deng, Chang-chun; Yang, Wan-qin; Zhang, Jian; Yang, Lin; Liu, Yang

    2015-11-01

    The mass loss and lignocellulose enzyme activities of Actinothuidium hookeri residues and Cystopteris montana leaf litter in coniferous forest and timberline of western Sichuan, China were investigated. The results showed that both the mass loss rates of A. hookeri and C. Montana in timberline were higher than those in coniferous forest, while enzyme activities in timberline were lower than those in coniferous forest which was contrast with the hypothesis. The mass loss of two ground covers had significant differences in different seasons. The mass loss rate of A. hookeri in snow-covered season accounted for 69.8% and 83.0% of the whole year' s in timberline and coniferous forest, while that of C. montana in the growing season accounted for 82.6% and 83.4% of the whole year' s in timberline and coniferous forest, respectively. C. montana leaf litter decayed faster in the growing season, which was consistent with its higher cellulase activity in the growing season. The result illustrated that the enzymatic hydrolysis of cellulose and hemicellulose might be the main driving force for the early stage of litter decomposition. Multiple linear regression analysis showed that environmental factors and initial litter quality could explain 45.8%-85.1% variation of enzyme activity. The enzyme activities of A. hookeri and C. montana in the process of decomposition were mainly affected by the freeze-thaw cycle in snow-covered season. PMID:26915177

  7. Genetic diversity and differentiation of the rhesus macaque (Macaca mulatta) population in western Sichuan, China, based on the second exon of the major histocompatibility complex class II DQB (MhcMamu-DQB1) alleles

    PubMed Central

    2014-01-01

    Abstracts Background Rhesus macaques living in western Sichuan, China, have been separated into several isolated populations due to habitat fragmentation. Previous studies based on the neutral or nearly neutral markers (mitochondrial DNA or microsatellites) showed high levels of genetic diversity and moderate genetic differentiation in the Sichuan rhesus macaques. Variation at the major histocompatibility complex (MHC) loci is widely accepted as being maintained by balancing selection, even with a low level of neutral variability in some species. However, in small and isolated or bottlenecked populations, balancing selection may be overwhelmed by genetic drift. To estimate microevolutionary forces acting on the isolated rhesus macaque populations, we examined genetic variation at Mhc-DQB1 loci in 119 wild rhesus macaques from five geographically isolated populations in western Sichuan, China, and compared the levels of MHC variation and differentiation among populations with that previously observed at neutral microsatellite markers. Results 23 Mamu-DQB1 alleles were identified in 119 rhesus macaques in western Sichuan, China. These macaques exhibited relatively high levels of genetic diversity at Mamu-DQB1. The Hanyuan population presented the highest genetic variation, whereas the Heishui population was the lowest. Analysis of molecular variance (AMOVA) and pairwise FST values showed moderate genetic differentiation occurring among the five populations at the Mhc-DQB1 locus. Non-synonymous substitutions occurred at a higher frequency than synonymous substitutions in the peptide binding region. Levels of MHC variation within rhesus macaque populations are concordant with microsatellite variation. On the phylogenetic tree for the rhesus and crab-eating macaques, extensive allele or allelic lineage sharing is observed betweenthe two species. Conclusions Phylogenetic analyses confirm the apparent trans-species model of evolution of the Mhc-DQB1 genes in these

  8. The Features of Condensate Water and Its Guide on Gas Proudction in upper Triassic Gas Reservoir of Western Sichuan Depression, China

    NASA Astrophysics Data System (ADS)

    Shang, C.; Lou, Z.

    2012-12-01

    In upper Triassic Xujiahe Formation of western Sichuan depression, China, there developed ultrathight sandstones reservoirs, of which the mean porosity is 4.02% and the permeability mode is less than 0.1×10-3μm2. Because of the ultrathight sandstones, thick gaseous- liquid phase transition develops in the upper Trassic Xujiahe Formation. The absolute quantity of gaseous water is lager. Due to the change of temperature and pressure at the wellhead, the gaseous water in gas reservoir becomes condensate water. Therefore, the condensate water of low salinity can be widely found at the original productive process in the Xujiahe Formation reservoir, such as wells named Lian 150, Xin 851, Xin 853, Xin 856, Dayi 101, Dayi 103. The main cations are K++Na+, while the anions are HCO3- and Cl-. The main water type is CaCl2, followed by NaHCO3, Na2SO4 and MgCl2. The PH of condensate water is 5.28-8.20 with mean value 6.40. The salinity of condensate water is lower than that of formation water. The milligram equivalent (mEq) percent of ion is used to study the features of condensate water. The anions (mEq) distribution of condensate water are scattered in ternary diagram, while that of formation water concentrate upon the SO42- and Cl- endpoints. The percent of HCO3-(mEq) in condensate water is higher than that of formation water. There is no obvious difference of cations mEq percent between condensate water and formation water, which indicates that condensate water strongly affected by formation water. Through this study, condensate water may originate from formation water and then be affected by complicated physical and chemical interactions. The condensate water is affected by gas and formation water. The relationship between condensate water and gas yield is very close. The variations of water yield, salinity and ions composition can reflect the change of gas yield. Taking well Xin 856 for example, which is located in Xinchang gas felid, there exist a relationship between

  9. Paleoproterozoic gold deposits in the Bald Hill and Coyote areas, Western Tanami, Western Australia

    NASA Astrophysics Data System (ADS)

    Bagas, Leon; Huston, David L.; Anderson, James; Mernagh, Terrence P.

    2007-01-01

    Significant gold deposits in the western Tanami region of Western Australia include deposits in the Bald Hill and Coyote areas. The ca. 1,864 Ma Bald Hill sequence of turbiditic and mafic volcanic rocks hosts the Kookaburra and Sandpiper deposits and a number of smaller prospects. The ca. 1,835 Ma turbiditic Killi Killi Formation hosts the Coyote deposit and several nearby prospects. The Kookaburra deposit forms as a saddle reef within a syncline, and the Sandpiper deposit is localized within graphitic metasedimentary rocks along a limb of an anticline. Gold in these deposits is hosted by anastomosing quartz-(-pyrite-arsenopyrite) veins within quartz-sericite schist with disseminated arsenopyrite, pyrite, and marcasite (after pyrrhotite). Based on relative timing relationships with structural elements, the auriferous veins are interpreted to have been emplaced before or during the ca. 1,835-1,825 Ma Tanami Orogeny (regional D1). Gold deposition is thought to have been caused by pressure drops associated with saddle reef formation (Kookaburra) and chemical reactions with graphitic rocks (Sandpiper). The Coyote deposit, the largest in the western Tanami region, consists of a number of ore lenses localized along the limbs of the Coyote Anticline, which formed during the Tanami Orogeny. The largest lenses are associated with the Gonzalez Fault, which is located along the steeply dipping southern limb of this fold. Gold was introduced at ca. 1,790 Ma into dilatant zones that formed in local perturbations along this fault during later reactivation (regional D5) towards the end of a period of granite emplacement. Gold is associated with quartz-chlorite-pyrite-(arsenopyrite-galena-sphalerite) veins with narrow (< 5 mm) chloritic selvages. A quartz-muscovite-biotite-K-feldspar-(tourmaline-actinolite-arsenopyrite) assemblage, which is interpreted to relate to granite emplacement, overprints the regional greenschist facies metamorphic assemblage. The mineralogical similarity

  10. Appraisal of iron deposits in southern and western Turkey

    USGS Publications Warehouse

    Gair, Jacob Eugene; Capan, Ussal Z.

    1972-01-01

    Between May 20 and June 17, 1969, previously known iron deposits were examined widely at eight separate localities in western Turkey. The object of the examinations was to learn the, nature, geologic setting, and approximate size of each deposit, to review prior estimates of size, and possibly recommend additional exploratory work.. The full extent of each deposit is poorly known at the present time, so recommended additional work entails drilling, digging trenches or pits, geologic mapping or, combinations of these activities. On Qaldagi Mountain an area of about 1 sq km is capped by bredciated chert under which may be a continuous zone of mixed iron oxides and chert fragments. The thickness of the ferruginous zone is poorly known but is as much as 12 meters, in at least one place. The- ferruginous material and chert appear to have formed by the weathering of serpentine, bun this concept needs further testing. Drilling is recommended to determine the grade, thickness, and extent-of the ferruginous zone beneath the cherty cap. Inasmuch as mining by hand sorting is in progress, part of the deposit can be considered to be marginally in the category of iron reserves. The Keceborlu iron deposit consists of earthy to slightly compacted hematite and limonite mixed with small chert fragments. The surface area underlain by ferruginous rock is about 5,000 to 7,500 sq meters. The maximum known thickness of the deposit is about 7 meters. Iron appears to have been concentrated by weathering and oxidation of cherty limestone. The deposit is probably either a remnant of a once more extensive weathered cap, or a sink hole filling. The Keceborlu area warrants a low priority for further exploration, but one drill hole is recommended to test the thickness of the deposit. The iron deposits at Mellec are layered and vein-magnetite replacements of limestone. The six known deposits are discontinuous. No additional. work is recommended. ' The Gilindire Iron deposit consists of irregular

  11. Beryllium deposits of the western Seward Peninsula, Alaska

    USGS Publications Warehouse

    Sainsbury, C.L.

    1963-01-01

    Deposits of beryllium ore in the Lost River area of the western Seward Peninsula, Alaska, consist of replacement veins, pipes, and stringer lodes is limestone in a zone about 7 miles long and 2 to 3 miles wide which is faulted and intruded by dikes and stocks. The ores are remarkably alike and typically consist of the following minerals, in percent: fluorite, 45-65; diaspore, 5-10; tourmaline, 0-10; chrysoberyl, 3-10; white mica, 0-5; small amounts of hematite, sulfide minerals, manganese oxide, other beryllium minerals; and traces of minerals not yet identified. The ores generally are cut by late veinlets which are of the same mineralogy as the groundmass ore, or which consist of fluorite, white mica, and euclase. The ores are fine grained, and many of the individual mineral grains, except fluorite, are less than 1 mm in size. The beryllium content of bulk samples of ore ranges from 0.11 to 0.54 percent (0.31 to 1.50 percent BeO). High-grade nodules, composed principally of chrysoberyl, diaspore, fluorite, and mica, contain as much as 6 percent BeO. Geochemical reconnaissance has disclosed other areas of anomalous beryllium in stream sediments elsewhere on the Seward Peninsula, generally around biotite granites that have them associated with tin deposits; additional exploration probably will disclose other deposits.

  12. Metallogeny of epithermal gold deposits in the western US Cordillera

    SciTech Connect

    Duke, N.A.

    1985-01-01

    The mid-Tertiary sediment-, volcanic-, and detachment fault-hosted epithermal gold deposits (EGDs) of the western US Cordillera favor the outboard side of the tectonically thickened miogeoanticlines. Post Mesozoic accretion, this cratonic shelf-oceanic basin transition zone underwent a period of extensional uplift that thinned the brittle upper crust through listric-normal and detachment faulting, and the decoupled metamorphic infrastructure by ductile necking. The EDGs formed in the upper crust peripheral to tectonically exposed metamorphic core complexes synchronously with active extension. They demonstrate close space/time relationships to the centers of ash flow tuff eruptions that characterized this period. In general the metal concentrated in EDGs had a common source and transport mechanism. The fact that major EGDs occur along obducted oceanic thrust plates indicates that the gold was originally scavaged from oceanic successions during dewatering along the thrust structures. The metal was again mobilized in meteoric dominated hot spring systems operating within volcani-tectonic sinks occurring at ignimbrite eruptive centers. As a result, the siting of both sediment- and volcanic-hosted EGDs is controlled largely by proximity to the mid-Tertiary paleosurface. Specific controls for the precipitation of gold varies with deposit type but critical behavior of the ore-bearing fluid and/or redox reactions between migrating fluids and reduced lithology crosscut by permeable structures are primary.

  13. Buddhist Education in Sichuan

    ERIC Educational Resources Information Center

    Long, Darui

    2002-01-01

    This paper is devoted to Buddhist education in Sichuan Province with a focus on Venerable Longlian's temple. It deals with the historical development of Chinese Buddhist education and makes statistic analysis of the available data. Venerable Longlian established the Sichuan Buddhist Institute for Nuns in the 1980s. It was the first modern school…

  14. Marine intervals in Neogene fluvial deposits of western Amazonia

    NASA Astrophysics Data System (ADS)

    Boonstra, Melanie; Troelstra, Simon; Lammertsma, Emmy; Hoorn, Carina

    2014-05-01

    Amazonia is one of the most species rich areas on Earth, but this high diversity is not homogeneous over the entire region. Highest mammal and tree-alpha diversity is found in the fluvio-lacustrine Pebas system, a Neogene wetland associated with rapid radiation of species. The estuarine to marine origin of various modern Amazonian fish, plants, and invertebrates has been associated with past marine ingressions into this freshwater Pebas system. The exact nature and age of these invasions is, however, debated. Here we present new evidence from fluvial and fluvio-lacustrine deposits of Neogene age in southeast Colombia, that point to periods of widespread marine conditions in western Amazonia. Our evidence is based on an analysis of marine palynomorphs, such as organic linings of foraminifera and dinoflagellate cysts, present in dark sandy clay sediments that outcrop along the Caqueta and Amazon rivers. Characteristically, the foraminiferal linings can be assigned to three benthic morphotypes only, e.g. Ammonia, Elphidium and Trochammina. This low diversity assemblage is associated with estuarine/marginal marine conditions. No distinct marine elements such as shelf or planktonic species were encountered. The observed foraminiferal linings and dinocyst assemblages are typical for a (eutrophic) shallow marine environment, suggesting that the Pebas freshwater wetland system occasionally changed to (marginal) marine. Although some reworked elements are found, a typical Neogene dinocyst taxon is commonly found supporting in situ deposition. Sedimentological features typical for tidal conditions that are reported for sites in Peru and northeastern Brazil likely relate to these marine ingressions. Sea level changes as well as foreland basin development related to Andes formation may have facilitated the entry of marine water during the Neogene.

  15. Critical Metals In Western Arctic Ocean Ferromanganese Mineral Deposits

    NASA Astrophysics Data System (ADS)

    Hein, J. R.; Spinardi, F.; Conrad, T. A.; Conrad, J. E.; Genetti, J.

    2013-12-01

    Little exploration for minerals has occurred in the Arctic Ocean due to ice cover and the remote location. Small deposits of seafloor massive sulfides that are rich in copper and zinc occur on Gakkel Ridge, which extends from Greenland to the Laptev Sea, and on Kolbeinsey and Mohns ridges, both located between Greenland and mainland Europe. However, rocks were recently collected by dredge along the western margin of the Canada Basin as part of the U.S. Extended Continental Shelf (ECS) program north of Alaska. Sample sites include steep escarpments on the Chukchi Borderland, a newly discovered seamount informally named Healy seamount, the southern part of Alpha-Mendeleev Ridge, and several basement outcrops in Nautilus Basin. These dredge hauls yielded three types of metal-rich mineralized deposits: ferromanganese crusts, ferromanganese nodules, and hydrothermal iron and manganese deposits. Chemical analyses of 43 crust and nodule samples show high contents of many critical metals needed for high-technology, green-technology, and energy and military applications, including cobalt (to 0.3 wt.%), vanadium (to 0.12 wt.%), zirconium (to 459 grams/tonne=ppm), molybdenum (to 453 g/t), the rare-earth elements (including scandium and yttrium; yttrium to 229 g/t), lithium (to 205 g/t), tungsten (to 64 g/t), and gallium (to 26 g/t). The metal contents of these Arctic Ocean crusts and nodules are comparable to those found throughout the global ocean, however, these Arctic Ocean samples are the first that have been found to be enriched in rare metal scandium. The metal contents of these samples indicate a diagenetic component. Crusts typically form by precipitation of metal oxides solely from seawater (hydrogenetic) onto rock surfaces producing a pavement, whereas nodules form by accretion of metal oxides, from both seawater and pore waters (diagenetic), around a nucleus on the surface of soft sediment. The best evidence for this diagenetic input to the crusts is that crusts

  16. Measuring and monitoring snow deposition, properties and processes in mountain catchments of Western North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Patterns of snow deposition, and the distribution of snow properties and processes in mountainous regions of Western North America are highly heterogeneous. Wind and topographic structure control snow deposition, causing tremendous spatial heterogeneity in the distribution of the snowcover and the ...

  17. Coking-coal deposits of the western United States

    USGS Publications Warehouse

    Berryhill, Louise R.; Averitt, Paul

    1951-01-01

    Geohydrologic systems in the Anadarko basin in the central United States are controlled by topography, climate, geologic structures, and aquifer hydraulic properties, all of which are the result of past geologic and hydrologic processes, including tectonics and diagenesis. From Late Cambrian through Middle Ordovician time, a generally transgressive but cyclic sea covered the area. The first deposits were permeable sand, followed by calcareous mud. During periods of sea transgression, burial diagenesis decreased porosity and permeability. During Pennsylvanian time, rapid sedimentation accompanied rapid subsidence in the Anadarko basin. A geopressure zone probably resulted when sediments with little permeability trapped depositional water in Lower Pennsylvanian sands. Burial diagenesis included compaction and thermal alteration of deeply buried organic material, which released carbon dioxide, water, and hydrocarbons. By Middle Pennsylvanian time, the sea had submerged most of the central United States, including the Ozarks, as tectonic activity reached its maximum. During Late Pennsylvanian and Early Permian time, the Ouachita uplift had been formed and was higher than the Ozarks. Uplift was accompanied by a regional upward tilt toward the Ouachita-Ozarks area; the sea receded westward, depositing large quantities of calcareous mud and clay, and precipitating evaporitic material in the restricted-circulation environment. By the end of Permian time, > 20,000 ft of Pennsylvanian and Permian sediments had been deposited in the Anadarko basin. These thick sediments caused rapid and extreme burial diagensis, including alteration of organic material During Permian time in the Ozarks area, development of the Ozark Plateau aquifer system commenced in the permeable Cambrian-Mississippian rocks near the St. Francois Mountains as the Pennsylvanian confining material was removed. Since Permian time, uplift diagenesis has been more active than burial diagenesis in the Anadarko

  18. Distribution of atmospheric marine salt depositions over Continental Western Europe.

    PubMed

    Delalieux, F; van Grieken, R; Potgieter, J H

    2006-06-01

    This contribution describes the distribution of marine salt aerosols in Belgium, France and Spain, as obtained from applying a kriging model to a set of data. The data was collected over a period of nine years and included wet as well as dry deposition results. It was found that the concentration of the salt particles decreased the fastest in Spain and the slowest in Belgium with increasing inland distance from the sea. These findings have implications for the degradation of monuments and historical buildings as a result of salt attack and ingress that often accompany degradation due to air pollution. PMID:16772114

  19. Geological setting and mineralization model for the Cleo gold deposit, Eastern Goldfields Province, Western Australia

    NASA Astrophysics Data System (ADS)

    Brown, Suzanne M.; Groves, David I.; Newton, Philip G.

    2002-10-01

    The Cleo gold deposit, containing 4.25 Moz Au (37.1 Mt at 3.6 g/t), is the western part of a continuous orebody divided by a north-south tenement boundary. The eastern part is known as Sunrise, and together the Cleo and Sunrise deposits contain nearly 8 Moz Au in resources and past production. The focus of this study is the Cleo deposit, located 50 km south of Laverton in the Eastern Goldfields Province of the Yilgarn Craton of Western Australia, hosted in an Archean sequence dominated by volcaniclastic rocks. The Sunrise Shear Zone divides the sequence into hanging wall and footwall components. The gently north-west-dipping shear zone controls the orientation of shear-zone parallel ore zones, which characteristically involve pyrite replacement of magnetite in banded iron formation. Steeply-dipping multistage veins in the hanging wall and footwall define the Western Lodes, ore zones that are oriented parallel to adjacent rhyodacite-porphyry dikes. Western Lode veins are developed in all rock types, and commonly contain free gold, as well as pyrite, arsenopyrite, tennantite and chalcopyrite. In the footwall block, the margins of steeply east-dipping rhyodacite porphyry dikes form the main control on localization of the Western Lodes. In the hanging wall, the Western Lodes parallel a porphyry dike, both structures exploiting a favourable orientation in the stratigraphic sequence. Rhyodacite porphyry dikes exhibit strained margins in the Sunrise Shear Zone. Gold-bearing Western Lodes veins cut porphyry dikes and cut the Sunrise Shear Zone with minimal offset. The association of the ~2,675 Ma rhyodacite porphyry dikes with the Western Lodes ore zones is caused by the structurally favourable orientation of the dikes, and not to any direct genetic relationship between rhyodacite porphyry magma and ore fluids, as the latter post-dated the former.

  20. Complex Floor Deposits Within Western Ganges Chasma, Valles Marineris

    NASA Technical Reports Server (NTRS)

    1997-01-01

    On October 26, 1997, MOC took this image of Mars 10 minutes after its closest approach to the planet (1:46 AM PST). The view shows the floor of western Ganges Chasma (7.8oS 51.8oW), covering an area 2.6 km (1.6 miles) wide by 45.4 km (28.2 miles) long at a resolution of 5 by 7.4 meters (16.4 by 24.3 feet) per picture element. The local time on Mars when the picture was taken was 4:35 PM.

    The center image (available at higher resolution as PIA01028) shows the northern portion of the area inscribed in the left image. The right image (PIA01029) shows the southern portion.

    Launched on November 7, 1996, Mars Global Surveyor entered Mars orbit on Thursday, September 11, 1997. The original mission plan called for using friction with the planet's atmosphere to reduce the orbital energy, leading to a two-year mapping mission from close, circular orbit (beginning in March 1998). Owing to difficulties with one of the two solar panels, aerobraking was suspended in mid-October and resumed in November 8. Many of the original objectives of the mission, and in particular those of the camera, are likely to be accomplished as the mission progresses.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  1. Geology, distribution, and classification of gold deposits in the western Qinling belt, central China

    USGS Publications Warehouse

    Mao, J.; Qiu, Y.; Goldfarb, R.J.; Zhang, Z.; Garwin, S.; Fengshou, R.

    2002-01-01

    Gold deposits of the western Qinling belt occur within the western part of the Qinling-Dabie-Sulu orogen, which is located between the Precambrian North China and Yangtze cratons and east of the Songpan-Ganzi basin. The early Paleozoic to early Mesozoic orogen can be divided into northern, central, and southern zones, separated by the Shangdan and Lixian-Shanyang thrust fault systems. The northern zone consists of an early Paleozoic arc accreted to the North China craton by ca. 450 Ma. The central zone, which contains numerous orogenic gold deposits, is dominated by clastic rocks formed in a late Paleozoic basin between the converging cratonic blocks. The southern zone is characterized by the easternmost exposure of Triassic sedimentary rocks of the Songpan-Ganzi basin. These Early to Late Triassic turbidities, in part calcareous, of the immense Songpan-Ganzi basin also border the western Qinling belt to the west. Carlinlike gold deposits are abundant (1) along a westward extension of the southern zone defined by a window of early Paleozoic clastic rocks extending into the basin, and (2) within the easternmost margin of the basinal rocks to the south of the extension, and in adjacent cover rocks of the Yangtze craton. Triassic and Early Jurassic synkinematic granitoids are widespread across the western Qinling belt, as well as in the Songpan-Ganzi basin. Orogenic lode gold deposits along brittle-ductile shear zones occur within greenschist-facies, highly deformed, Devonian and younger clastic rocks of the central zone. Mainly coarse-grained gold, along with pyrite, pyrrhotite, arsenopyrite, and minor base metal sulfides, occur in networks of quartz veinlets, brecciated wall rock, and are dissminated in altered wall rock. Isotopic dates suggest that the deposits formed during the Late Triassic to Middle Jurassic as the leading edge of the Yangtze craton was thrust beneath rocks of the western Qinling belt. Many gold-bearing placers are distributed along the river

  2. ATLAS OF AIR QUALITY AND DEPOSITION IN OR NEAR FORESTS OF THE WESTERN UNITED STATES

    EPA Science Inventory

    An atlas of air quality and deposition data has been compiled to make air pollution data and information more accessible to biologists and ecologists working in western forests. ata from the 1985 National Acid precipitation Assessment program Emission Inventory are used to charac...

  3. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than 1 year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA (Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie in French) have been deployed in the western Mediterranean region during 1 to 3 years depending on the station. The sites include, from south to north, Lampedusa, Majorca, Corsica, Frioul and Le Casset (southern French Alps). Deposition measurements are performed on a common weekly period at the five sites. The mean dust deposition fluxes are higher close to the northern African coasts and decrease following a south-north gradient, with values from 7.4 g m-2 year-1 in Lampedusa (35°31' N, 12°37' E) to 1 g m-2 year-1 in Le Casset (44°59' N, 6°28' E). The maximum deposition flux recorded is of 3.2 g m-2 wk-1 in Majorca with only two other events showing more than 1 g m-2 wk-1 in Lampedusa, and a maximum of 0.5 g m-2 wk-1 in Corsica. The maximum value of 2.1 g m-2 year-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 g m-2 year-1). From the 537 available samples, 98 major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations for the studied period. Despite the large size of African dust plumes detected by satellites, more than 80 % of the major dust deposition events are recorded at only one station, suggesting that the dust

  4. Variability of mineral dust deposition in the western Mediterranean basin and South-East of France

    NASA Astrophysics Data System (ADS)

    Vincent, J.; Laurent, B.; Losno, R.; Bon Nguyen, E.; Roullet, P.; Sauvage, S.; Chevaillier, S.; Coddeville, P.; Ouboulmane, N.; di Sarra, A. G.; Tovar-Sánchez, A.; Sferlazzo, D.; Massanet, A.; Triquet, S.; Morales Baquero, R.; Fornier, M.; Coursier, C.; Desboeufs, K.; Dulac, F.; Bergametti, G.

    2015-12-01

    Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than one year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA ("Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie" in French) have been deployed in the western Mediterranean region during one to three years depending on the station. The sites include, from South to North, Lampedusa Isl., Mallorca Isl., Corsica Isl., Frioul Isl. and Le Casset (South of French Alps). Deposition measurements are performed on a common weekly period at the 5 sites. The mean Saharan dust deposition fluxes are higher close to the North African coasts and decrease following a South to North gradient, with values from 7.4 g m-2 yr-1 in Lampedusa (35°31' N-12°37' E) to 1 g m-2 yr-1 in Le Casset (44°59' N-6°28' E). The maximum deposition flux recorded is of 3.2 g m-2 wk-1 in Mallorca with only 2 other events showing more than 1 g m-2 wk-1 in Lampedusa, and a maximum of 0.5 g m-2 wk-1 in Corsica. The maximum value of 2.1 g m-2 yr-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 g m-2 yr-1). From the 537 available samples, ninety eight major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations. Despite the large size of African dust plumes detected by satellites, more than eighty percent of the major dust deposition events are recorded at only one station

  5. Nutrient and trace metals atmospheric deposition in the western Mediterranean: source apportionment

    NASA Astrophysics Data System (ADS)

    Desboeufs, Karine; Bon Nguyen, Elisabeth; Simeoni, Pasquale; Dulac, François

    2015-04-01

    Mediterranean Sea is a typical LNLC region particularly well adapted to assess the role of ocean-atmosphere exchanges. Throughout the summer stratification period when diffusion through the thermocline is low, atmospheric inputs become the main external source of nutrients to the surface open waters of the MS, mostly by wet deposition in the western basin.Here, we show a 3-yr time continuous series of nutrient (N, P) and trace metals (Cr, Cu, Fe, P, V, Zn) total deposition fluxes in Corsica. Between March 2008 and May 2011, a monitoring station was operated with a weekly sampling time step at Galeria (42.44°N; 8.65°E) on the western coast of Corsica in the framework of the projects DUNE (a Dust Experiment in a Low Nutrient Low Chlorophyll Ecosystem) and then ChArMEx (the Chemistry-Aerososl Mediterranean Experiment). Monthly fluxes were measured to assess the temporal variability of the measured elements over the Western Mediterranean. Nutrients deposition presented a clear seasonal pattern which was different for each studied nutrients, emphasizing a difference of sources for the nutrients. The results show no dust event larger than 0.68 g m-2 so that the maximum yearly flux was among the lowest ever observed in Corsica (1.7 g m-2 y-1). One dust deposition event could contribute up to 30% of yearly deposition fluxes of nutrient and trace metals, confirming the high temporal variability of atmospheric deposition. However a source apportionment work via statistical methods shows that the yearly deposition fluxes of considered nutrient and trace metals were dominated by anthropogenic sources, except for Fe. Acknowledgements: DUNE project was funded by ANR. ChArMEx (http://charmex.lsce.ipsl.fr) is funded by CNRS/INSU, ADEME, CEA and Météo-France in the framework of the programme MISTRALS (http://www.mistrals-home.org)

  6. One new species of the genus Nigrimacula Shi, Bian & Zhou, 2016 (Orthoptera: Meconematinae) from Sichuan, China.

    PubMed

    Wang, Hai-Jian; Shi, Fu-Ming

    2016-01-01

    The paper describels one new species, i.e. Nigrimacula sichuanensis Wang & Shi, sp. nov. from Sichuan, China, and provides photographs of morphological characters. The type material is deposited in the Museum of Hebei University. PMID:27395697

  7. Are climate warming and enhanced atmospheric deposition of sulfur and nitrogen threatening tufa landscapes in Jiuzhaigou National Nature Reserve, Sichuan, China?

    PubMed

    Qiao, Xue; Du, Jie; Lugli, Stefano; Ren, Jinhai; Xiao, Weiyang; Chen, Pan; Tang, Ya

    2016-08-15

    Massive deposition of calcium carbonate in ambient temperature waters (tufa) can form magnificent tufa landscapes, many of which are designated as protected areas. However, tufa landscapes in many areas are threatened by both local anthropogenic activities and climate change. This study, for the first time, posed the question whether the tufa landscape degradation (characterized by tufa degradation and increased biomass of green algae) in Jiuzhaigou National Nature Reserve of China is partially caused by regional air pollution and climate warming. The results indicate that wet deposition (including rain and snow) polluted by anthropogenic SO2, NOx, and NH3 emissions dissolves exposed tufa and may considerably reduce tufa deposition rate and even cause tufa dissolution within shallow waters. These effects of wet deposition on tufa enhanced as pH of wet deposition decreased from 8.01 to 5.06. Annual Volume Weighted Mean concentration of reactive nitrogen (including NH4(+) and NO3(-)) in wet deposition (26.1μmolL(-1)) was 1.8 times of the corresponding value of runoff (14.8μmolL(-1)) and exceeded China's national standard of total nitrogen in runoff for nature reserves (14.3μmolL(-1)), indicating a direct nitrogen fertilization effect of wet deposition on green algae. As water temperature is the major limiting factor of algal growth in Jiuzhaigou and temperature in the top layer (0-5cm) of runoff (depth<1m, no canopy coverage of trees and shrubs) was significantly higher at the sites with increased biomass of green algae (p<0.05), climate warming in this region would favor algal growth. In sum, this study suggests that climate warming and enhanced sulfur and nitrogen deposition have contributed to the current degradation of tufa landscape in Jiuzhaigou, but in order to quantify the contributions, further studies are needed, as many other anthropogenic and natural processes also influence tufa landscape evolution. PMID:27110983

  8. Synthesis of late Paleozoic and Mesozoic eolian deposits of the Western Interior of the United States

    NASA Astrophysics Data System (ADS)

    Blakey, Ronald C.; Peterson, Fred; Kocurek, Gary

    1988-04-01

    Late Paleozoic and Mesozoic eolian deposits include rock units that were deposited in ergs (eolian sand seas), erg margins and dune fields. They form an important part of Middle Pennsylvanian through Upper Jurassic sedimentary rocks across the Western Interior of the United States. These sedimentary rock units comprise approximately three dozen major eolian-bearing sequences and several smaller ones. Isopach and facies maps and accompanying cross sections indicate that most eolian units display varied geometry and complex facies relations to adjacent non-eolian rocks. Paleozoic erg deposits are widespread from Montana to Arizona and include Pennsylvanian formations (Weber, Tensleep, Casper and Quadrant Sandstones) chiefly in the Northern and Central Rocky Mountains with some deposits (Hermosa and Supai Groups) on the Colorado Plateau. Lower Permian (Wolfcampian) erg deposits (Weber, Tensleep, Casper, Minnelusa, Ingleside, Cedar Mesa, Elephant Canyon, Queantoweap and Esplanade Formations) are more widespread and thicken into the central Colorado Plateau. Middle Permian (Leonardian I) erg deposits (De Chelly and Schnebly Hill Formations) are distributed across the southern Colorado Plateau on the north edge of the Holbrook basin. Leonardian II erg deposits (Coconino and Glorieta Sandstones) are slightly more widespread on the southern Colorado Plateau. Leonardian III erg deposits formed adjacent to the Toroweap-Kaibab sea in Utah and Arizona (Coconino and White Rim Sandstones) and in north-central Colorado (Lyons Sandstone). Recognized Triassic eolian deposits include major erg deposits in the Jelm Formation of central Colorado-Wyoming and smaller eolian deposits in the Rock Point Member of the Wingate Sandstone and upper Dolores Formation, both of the Four Corners region. None of these have as yet received a modern or thorough study. Jurassic deposits of eolian origin extend from the Black Hills to the southern Cordilleran arc terrain. Lower Jurassic intervals

  9. CO2 deposition over the multi-year ice of the western Weddell Sea

    NASA Astrophysics Data System (ADS)

    Zemmelink, H. J.; Delille, B.; Tison, J. L.; Hintsa, E. J.; Houghton, L.; Dacey, J. W. H.

    2006-07-01

    Field measurements by eddy correlation (EC) indicate an average uptake of 0.6 g CO2 m-2 d-1 by the ice-covered western Weddell Sea in December 2004. At the same time, snow that covers ice floes of the western Weddell Sea becomes undersaturated with CO2 relative to the atmosphere during early summer. Gradients of CO2 from the ice to the atmosphere do not support significant diffusive fluxes and are not strong enough to explain the observed CO2 deposition. We hypothesize that the transport of air through the snow pack is controlled by turbulence and that undersaturation of CO2 is caused by biological productivity at the ice-snow and snow-atmosphere interface. The total carbon uptake by the multi-year ice zone of the western Weddell Sea in December could have been as high as 6.6 Tg C y-1.

  10. Quaternary geology and sapphire deposits from the BO PHLOI gem field, Kanchanaburi Province, Western Thailand

    NASA Astrophysics Data System (ADS)

    Choowong, Montri

    2002-01-01

    One of the most famous blue sapphire deposits in Thailand and SE Asia is from the Bo Phloi District, Kanchanaburi Province, Western Thailand. This paper presents the results of our gemstone investigation as well as establishing the Bo Phloi depositional sequence as one of the Quaternary Type Sections in the region. Relationships among the sedimentology, depositional sequences and geomorphology were investigated in order to understand the gemstone depositional features. Sedimentary structures and textures of the sequences show that the deposition of gemstones is related genetically to fluvial processes. Gemstones are recognized in floodplain and low terrace deposits where gemstone paystreaks concentrate mostly inside layers of gravel beds and foreset-bedded gravels lithofacies. C-14 dating of wood and peat within gemstone-bearing layers indicated that the deposit formed during the middle to late Pleistocene. The gemstone-bearing gravel bed defines a north-south trend along the incised palaeo-channel of an ancient braided river system in the middle part of the basin.

  11. The geologic relationships of industrial mineral deposits and asbestos in the western united states

    USGS Publications Warehouse

    VanGosen, B.S.

    2009-01-01

    In recent years, U.S. regulatory agencies have placed emphasis on identifying and regulating asbestos dust exposures in the mining environment, with a particular focus upon industrial mineral deposits in which asbestos occurs as an accessory mineral. Because asbestos minerals form in specific geologic environments, only certain predictable types of industrial mineral deposits can potentially host asbestos mineralization. By applying a basic knowledge of asbestos geology, the costly and time consuming efforts of asbestos monitoring and analyses can be directed towards those mineral deposit types most likely to contain asbestos mineralogy, while saving efforts on the mineral deposits that are unlikely to contain asbestos. While the vast majority of industrial mineral deposits in the Western United States are asbestos-free, there are several types that can, in some instances, host asbestos mineralization, or be closely associated with it. These industrial mineral deposits include a few types of aggregate, dimension, and decorative stone, and some deposits of chromite-nickel, magnesite, nepheline syenite, olivine, rare earth elements, talc, vermiculite, and wollastonite.

  12. Biogeochemical and Ecological Effects of Nitrogen Deposition in Western North America

    NASA Astrophysics Data System (ADS)

    Fenn, M. E.

    2003-12-01

    The unique geographic, demographic, climatic and edaphic conditions of the West determine N deposition rates and biogeochemical and ecological responses to N deposition. In the western United States large regions are exposed to low N deposition levels with interspersed hotspots of elevated N deposition near urban areas or large agricultural emissions sources. Nitrogen emissions also contribute to ozone formation and regional haze and visibility impairment, the latter an effect that is observed in remote sites including several high profile national parks and wilderness areas. Recent studies suggest that N enrichment impacts are generally more important in western terrestrial systems than soil acidification effects. In the Pacific Northwest, California and Colorado sensitive organisms such as lichens and phytoplankton demonstrate deleterious biological effects with N deposition levels as low as 3-8 kg ha-1 yr-1. Increased streamwater nitrate export has been reported from southern California forests and chaparral catchments, high elevation watersheds in the Colorado Front Range, and in the most exposed regions of the southwestern Sierra Nevada. Evidence suggests that in some regions N deposition alters plant community composition, decreases mycorrhizal diversity, and also increases biomass accumulation, carbon allocation patterns and fire frequency. Several factors predispose Western semiarid ecosystems to N saturation as will be demonstrated by the San Bernardino Mountains case study (southern California). Edaphic conditions generally favor high nitrification rates relative to N mineralization. Nitrate from nitrification and atmospheric deposition accumulates in soil and on plant surfaces during prolonged dry periods. Under conditions of chronic N deposition, the N cycle becomes highly open in nature as excess N is exported in runoff and as gaseous emissions from soil. Actively nitrifying soils and temporal asynchrony between the period of plant N demand and nitrate

  13. Mega debris flow deposits on the western Wilkes Land margin, East Antarctica

    USGS Publications Warehouse

    Donda, F.; O'Brien, P.E.; De Santis, L.; Rebesco, M.; Brancolini, Giuliano

    2007-01-01

    Multichannel seismic data collected off Western Wilkes Land (East Antarctica) reveal the occurrence of mega debris flow deposits on the lower slope and rise that were formed throughout the Miocene. Commonly, debris flow units are separated by thin deposits of well-stratified facies, interpreted as predominantly glaciomarine mixed contouritic and distal turbidite deposits. These units could act as weak layers and could have played a major role in the slope instability. High sedimentation rates, due to large amounts of sediment delivered from a temperate, wet-based ice sheet, constituted a key factor in the sediment failures. The main trigger mechanism would probably have been earthquakes enhanced by isostatic rebound following major ice sheet retreats.

  14. The economic potential of El-Gedida glauconite deposits, El-Bahariya Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El-Habaak, Galal; Askalany, Mohamed; Faraghaly, Mohamed; Abdel-Hakeem, Mahmoud

    2016-08-01

    The mining work at El-Gedida iron mine, El-Bahariya Oasis, in the Western Desert of Egypt extracts commercial iron ore deposits without attention paid to the large glauconite deposits overlying these iron ore deposits. For this reason, the present paper aims at evaluating and attracting the attention to these glauconite deposits as alternative potassium fertilizers. The study was achieved by investigating mineralogical, physical and chemical properties of the green deposits. Mineralogical and physical properties involved the determination of glauconite pellets content in different grain size fractions relative to impurities and the analysis of the percentage of clay matrix and grain size distribution. Different pre-treatment strategies and methods including comminution, sieving, magnetic separation, and X-ray diffraction were used for investigating those mineralogical and physical properties. On the other hand, chemical analyses included potassium content, heavy metal concentrations, and pH and salinity measurements. The major elements and trace elements were measured using ICP-OES and the pH was measured using a pH conductometer. Moreover, this study investigated the nature of grain boundaries and the effect of sieving on glauconite beneficiation. Results of this study suggest that El-Gedida glauconite deposits are mineralogically, physically and chemically suitable for exploitation and can be beneficiated for use as an alternative potassium fertilizer.

  15. Geodynamic setting of mineralization of Mississippi Valley-type deposits in world-class Sichuan-Yunnan-Guizhou Zn-Pb triangle, southwest China: Implications from age-dating studies in the past decade and the Sm-Nd age of Jinshachang deposit

    NASA Astrophysics Data System (ADS)

    Zhang, Changqing; Wu, Yue; Hou, Lin; Mao, Jingwen

    2015-05-01

    The Sichuan-Yunnan-Guizhou (S-Y-G) Zn-Pb triangle is a world-class metallogenic belt in southwestern China that contains hundreds of carbonate-hosted giant-to-small epigenetic Zn-Pb deposits. Here, we provide an overview of the ore geology, geochemistry and ore-forming fluids of the major Zn-Pb deposits in this area. These deposits are most likely Mississippi Valley-type (MVT) deposits that formed as a result of the regional migration of basinal brines along large fault systems and more minor secondary structures. The Sm-Nd age (201 ± 6.2 Ma) of ore-stage fluorite from the Jinshachang Zn-Pb deposit, within northeast Yunnan province, China, reveals this deposit formed during the Late Triassic, consistent with the majority of the published isotopic ages for other Zn-Pb deposits in the S-Y-G MVT triangle. These fluorite samples have initial 87Sr/86Sr ratios of 0.711385-0.711463 and εNd values of -8.4 to -8.7, confirming the basin-related nature of the mineralizing fluids. Published geochronological data combined with basic features of MVT deposits (e.g., geology, geochemistry, and ore-forming fluids) and the geological evolution of the study area has enabled us to develop a model for the Zn-Pb mineralization, where this word-class MVT belt has formed as a result of the regional-scale migration of basinal fluids coincident with tectonic activity along ore-controlling structures (e.g., thrust-fold systems). Both the fluid migration and the tectonic activity were probably triggered by the late Indosinian Orogeny, which in turn was a response to the closure of the Paleo-Tethys Ocean.

  16. Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity

    NASA Astrophysics Data System (ADS)

    Martino, M.; Hamilton, D.; Baker, A. R.; Jickells, T. D.; Bromley, T.; Nojiri, Y.; Quack, B.; Boyd, P. W.

    2014-07-01

    The atmospheric deposition of both macronutrients and micronutrients plays an important role in driving primary productivity, particularly in the low-latitude ocean. We report aerosol major ion measurements for five ship-based sampling campaigns in the western Pacific from ~25°N to 20°S and compare the results with those from Atlantic meridional transects (~50°N to 50°S) with aerosols collected and analyzed in the same laboratory, allowing full incomparability. We discuss sources of the main nutrient species (nitrogen (N), phosphorus (P), and iron (Fe)) in the aerosols and their stoichiometry. Striking north-south gradients are evident over both basins with the Northern Hemisphere more impacted by terrestrial dust sources and anthropogenic emissions and the North Atlantic apparently more impacted than the North Pacific. We estimate the atmospheric supply rates of these nutrients and the potential impact of the atmospheric deposition on the tropical western Pacific. Our results suggest that the atmospheric deposition is P deficient relative to the needs of the resident phytoplankton. These findings suggest that atmospheric supply of N, Fe, and P increases primary productivity utilizing some of the residual excess phosphorus (P*) in the surface waters to compensate for aerosol P deficiency. Regional primary productivity is further enhanced via the stimulation of nitrogen fixation fuelled by the residual atmospheric iron and P*. Our stoichiometric calculations reveal that a P* of 0.1 µmol L-1 can offset the P deficiency in atmospheric supply for many months. This study suggests that atmospheric deposition may sustain ~10% of primary production in both the western tropical Pacific.

  17. Mixtures of clays and sulfates within deposits in western Melas Chasma, Mars

    NASA Astrophysics Data System (ADS)

    Weitz, Catherine M.; Noe Dobrea, Eldar; Wray, James J.

    2015-05-01

    We have utilized several data sets from multiple spacecraft that have been acquired over a continuous observation campaign across the southwestern Melas Chasma region of Mars. The blocky deposit observed on the chasma floor and on portions of the southern wallrock consists of mixtures of light- and medium-toned materials that exhibit displacement structures consistent with transport down the wallrock and onto the chasma floor. CRISM visible and near-infrared reflectance spectra of the light-toned blocks suggest mixtures of nontronite, jarosite, Al-clays, hydrated silica, and/or an acid leached clay. The medium-toned blocks typically lack spectral features or exhibit signatures of polyhydrated sulfates. Bright layered mounds embayed by blocky deposit materials display spectra consistent with Ca-sulfates (gypsum and/or bassanite) that may have resulted from precipitation of less soluble Ca-rich minerals during ponding and evaporation of dilute fluids along the western chasma floor. Draping across some wallrock slopes is a light-toned deposit that sometimes overlies a blocky, layered, and spectrally bland medium-toned deposit. The light-toned deposit exhibits spectra consistent with mixtures of materials that may include jarosite, acid-leached clays, silica, poorly crystalline clays, and polyhydrated sulfates. Hesperian-age valleys dissect the medium-toned deposit along some wallrock slopes and may be partially filled in by light-toned deposits. The draping nature of these deposits can best be explained by airfall, either volcanic ash or atmospheric dust, with ice/snow accumulation perhaps controlling sedimentation along the wallrock. An examination of other regional hydrated deposits around southwestern Melas indicates similar draping deposits occur farther east and west along the wallrock, whereas layered sulfates to the southeast consist of monohydrated and polyhydrated sulfates that are similar to interior layered deposits found in many of the chasmata. Small opal

  18. Texture and depositional history of near-surface alluvial deposits in the central part of the western San Joaquin Valley, California

    USGS Publications Warehouse

    Laudon, Julie; Belitz, Kenneth

    1989-01-01

    Saline conditions and associated high levels of selenium and other soluble trace elements in soil, shallow ground water, and agricultural drain water of the western San Joaquin Valley, California, have prompted a study of the texture of near-surface alluvial deposits in the central part of the western valley. Texture is characterized by the percentage of coarse-grained sediment present within a specified subsurface depth interval and is used as a basis for mapping the upper 50 feet of deposits. Resulting quantitative descriptions of the deposits are used to interpret the late Quaternary history of the area. Three hydrogeologic units--Coast Range alluvium, flood-basin deposits, and Sierran sand--can be recognized in the upper 50 feet of deposits in the central part of the western San Joaquin Valley. The upper 30 feet of Coast Range alluvium and the adjacent 5 to 35 feet of flood-basin deposits are predominantly fine grained. These fine-grained Coast Range deposits are underlain by coarse-grained channel deposits. The fine-grained flood basin deposits are underlain by coarse-grained Sierran sand. The extent and orientation of channel deposits below 20 feet in the Coast Range alluvium indicate that streams draining the Coast Range may have been tributary to the axial stream that deposited the Sierran sand and that streamflow may have been to the southeast. The fining-upward stratigraphic sequence in the upper 50 feet of deposits and the headward retreat of tributary stream channels from the valley trough with time support a recent hypothesis of climatic control of alluviation in the western San Joaquin Valley.

  19. The boron isotope geochemistry of the neogene borate deposits of western Turkey

    NASA Astrophysics Data System (ADS)

    Palmer, M. R.; Helvaci, C.

    1997-08-01

    We have analyzed the boron isotope composition of 80 borate minerals (major minerals: borax, colemanite, and ulexite; minor minerals: veatchite-A, tunellite, kernite, terrugite, probertite, meyer-hofferite, inderite, inyoite, hydroboracite, howlite, and pandermite) from the main deposits (Kirka, Bigadiç, and Emet) and two smaller deposits (Kestelek and Sultançayir) in the western Turkish borate deposits. Forty-three samples were also analysed for their Sr isotope composition. The data span a wide range in δ11B values from -1.6%o to -25.3%o. The δ 11B values of the main borate minerals are largely controlled by their mineralogy and the pH of the brines from which they precipitated. An inverse correlation between the average δ 11B and 87Sr/86Sr ratios of colemanite in the different deposits suggests there is some variation in the sources of boron and Sr to the deposits. Emet has the highest contribution from aluminosilicates and Kirka the highest contribution from Eocene carbonates, with Bigadiç occupying an intermediate position. The δ11B values of the minor borate minerals distinguish between those which are primary precipitates from the original brines (or formed from primary borates without boron loss from the system) and those which formed from alteration of preexisting borate minerals with substantial loss of boron from the system.

  20. A new Burgess Shale-type deposit from the Ediacaran of western Mongolia

    NASA Astrophysics Data System (ADS)

    Dornbos, Stephen Q.; Oji, Tatsuo; Kanayama, Akihiro; Gonchigdorj, Sersmaa

    2016-03-01

    Preservation of soft-bodied organisms is exceedingly rare in the fossil record. One way that such fossils are preserved is as carbonaceous compressions in fined-grained marine sedimentary rocks. These deposits of exceptional preservation are known as Burgess Shale-type (BST) deposits. During the Cambrian Period, BST deposits are more common and provide a crucial view of early animal evolution. The earliest definitive fossil evidence for macroscopic animal-grade organisms is found in the preceding Ediacaran Period. BST deposits from the Ediacaran are rarer and lack conclusive evidence for animals. Here we report the discovery of a new Ediacaran BST deposit with exceptional preservation of non-mineralizing macro-organisms in thinly bedded black shale from Zavkhan Province, western Mongolia. This fossil assemblage, here named the Zuun-Arts biota, currently consists of two new species of probable macroscopic multicellular benthic algae. One species, Chinggiskhaania bifurcata n. gen., n. sp., dominates the biota. The other species, Zuunartsphyton delicatum n. gen., n. sp., is known from three specimens. SEM-EDS analysis shows that the fossils are composed of aluminosilicate clay minerals and some carbon, a composition comparable to fossils from the Cambrian Burgess Shale biota. This discovery opens a new window through which to view late Precambrian life.

  1. A new Burgess Shale-type deposit from the Ediacaran of western Mongolia.

    PubMed

    Dornbos, Stephen Q; Oji, Tatsuo; Kanayama, Akihiro; Gonchigdorj, Sersmaa

    2016-01-01

    Preservation of soft-bodied organisms is exceedingly rare in the fossil record. One way that such fossils are preserved is as carbonaceous compressions in fined-grained marine sedimentary rocks. These deposits of exceptional preservation are known as Burgess Shale-type (BST) deposits. During the Cambrian Period, BST deposits are more common and provide a crucial view of early animal evolution. The earliest definitive fossil evidence for macroscopic animal-grade organisms is found in the preceding Ediacaran Period. BST deposits from the Ediacaran are rarer and lack conclusive evidence for animals. Here we report the discovery of a new Ediacaran BST deposit with exceptional preservation of non-mineralizing macro-organisms in thinly bedded black shale from Zavkhan Province, western Mongolia. This fossil assemblage, here named the Zuun-Arts biota, currently consists of two new species of probable macroscopic multicellular benthic algae. One species, Chinggiskhaania bifurcata n. gen., n. sp., dominates the biota. The other species, Zuunartsphyton delicatum n. gen., n. sp., is known from three specimens. SEM-EDS analysis shows that the fossils are composed of aluminosilicate clay minerals and some carbon, a composition comparable to fossils from the Cambrian Burgess Shale biota. This discovery opens a new window through which to view late Precambrian life. PMID:26988136

  2. A new Burgess Shale-type deposit from the Ediacaran of western Mongolia

    PubMed Central

    Dornbos, Stephen Q.; Oji, Tatsuo; Kanayama, Akihiro; Gonchigdorj, Sersmaa

    2016-01-01

    Preservation of soft-bodied organisms is exceedingly rare in the fossil record. One way that such fossils are preserved is as carbonaceous compressions in fined-grained marine sedimentary rocks. These deposits of exceptional preservation are known as Burgess Shale-type (BST) deposits. During the Cambrian Period, BST deposits are more common and provide a crucial view of early animal evolution. The earliest definitive fossil evidence for macroscopic animal-grade organisms is found in the preceding Ediacaran Period. BST deposits from the Ediacaran are rarer and lack conclusive evidence for animals. Here we report the discovery of a new Ediacaran BST deposit with exceptional preservation of non-mineralizing macro-organisms in thinly bedded black shale from Zavkhan Province, western Mongolia. This fossil assemblage, here named the Zuun-Arts biota, currently consists of two new species of probable macroscopic multicellular benthic algae. One species, Chinggiskhaania bifurcata n. gen., n. sp., dominates the biota. The other species, Zuunartsphyton delicatum n. gen., n. sp., is known from three specimens. SEM-EDS analysis shows that the fossils are composed of aluminosilicate clay minerals and some carbon, a composition comparable to fossils from the Cambrian Burgess Shale biota. This discovery opens a new window through which to view late Precambrian life. PMID:26988136

  3. Geochemical discrimination of five pleistocene Lava-Dam outburst-flood deposits, western Grand Canyon, Arizona

    USGS Publications Warehouse

    Fenton, C.R.; Poreda, R.J.; Nash, B.P.; Webb, R.H.; Cerling, T.E.

    2004-01-01

    Pleistocene basaltic lava dams and outburst-flood deposits in the western Grand Canyon, Arizona, have been correlated by means of cosmogenic 3He (3Hec) ages and concentrations of SiO2, Na2O, K2O, and rare earth elements. These data indicate that basalt clasts and vitroclasts in a given outburst-flood deposit came from a common source, a lava dam. With these data, it is possible to distinguish individual dam-flood events and improve our understanding of the interrelations of volcanism and river processes. At least five lava dams on the Colorado River failed catastrophically between 100 and 525 ka; subsequent outburst floods emplaced basalt-rich deposits preserved on benches as high as 200 m above the current river and up to 53 km downstream of dam sites. Chemical data also distinguishes individual lava flows that were collectively mapped in the past as large long-lasting dam complexes. These chemical data, in combination with age constraints, increase our ability to correlate lava dams and outburst-flood deposits and increase our understanding of the longevity of lava dams. Bases of correlated lava dams and flood deposits approximate the elevation of the ancestral river during each flood event. Water surface profiles are reconstructed and can be used in future hydraulic models to estimate the magnitude of these large-scale floods.

  4. Structure and formation conditions of paleogene coal-bearing deposits of Western Kamchatka

    SciTech Connect

    Polyanskii, B.V.

    1995-03-01

    Peculiarities of lithofacial composition and cyclic structure of the Lower-Middle Paleogene volcano-terrigenous coal-bearing deposits of the Western Kamchatka marginal sedimentary basin are discussed. Unstable sedimentation under delta progradation environments is shown to be prevalent. Such conditions were favorable for coal formation of deltaic and alluvial-estuarine types. Against a background of the marine-coastal high rate (avalanche) sedimentation, short-lived conditions for dominantly allochthonous coal formation in the environment of humid, warm temperature climate and high changeable sedimentation rates were distinguished. The clastic material in the basin originates from two provenances, represented by Pre-Paleogene, mainly Cretaceous rocks. The Central Range supplied mainly coarse-grained graywacke material. The western continental denudation areas, consisting of sedimentary and igneous rocks (including granites), supplied fine-grained terrigenous graywacke-arkosic material.

  5. Geology and timing of mineralization at the Cangshang gold deposit, north-western Jiaodong Peninsula, China

    USGS Publications Warehouse

    Zhang, X.; Cawood, Peter A.; Wilde, S.A.; Liu, R.; Song, H.; Li, W.; Snee, L.W.

    2003-01-01

    The Cangshang gold deposit of the northwestern Jiaodong Peninsula contains reserves of greater than 50 tonnes (t) and is developed by the largest open pit gold mine in China. This deposit is a Jiaojia-style (i.e. disseminated-and-veinlet) deposit. It is controlled by the San-Cang fault zone, which trends ???040?? and dips 40-75??SE at the mine site. The main (no. 1) orebody lies between a hanging wall of Precambrian metamorphic rocks (mainly amphibolite) of the Fenzishan Group and a footwall composed of the Mesozoic Linglong granitoid. The ore zone is mainly composed of pyritized, sericitized and silicified granitoid, which has undergone variable degrees of cataclasis. SHRIMP U-Pb dating of zircon indicates that the protolith of the hanging wall amphibolite was formed at 2530 ?? 17 Ma and underwent metamorphism at 1852 ?? 37 Ma. The footwall granodiorite has been dated at 166 ?? 4 Ma, whereas zircons from the ore zone yield a younger age of 154 ?? 5 Ma. Cathodoluminescence images of zircons from the granodiorite and ore zone show oscillatory zonation indicative of an igneous origin for both and the ages of these zircons, therefore, are all interpreted to be representative of magmatic crystallization. Dating of sericite by 40Ar-39Ar has been used to directly determine the timing of formation of the Cangshang deposit, providing the first time absolute age on formation of the Jiaojia-style gold deposits. The well-defined age of 121.3 ?? 0.2 Ma provides the precise timing of gold mineralization at the Cangshang deposit. This age is consistent with those of Linglong-style (vein type) gold mineralization, also from the north-western Jiaodong Peninsula, at between 126 and 120 Ma. Therefore, our work indicates that both styles of gold deposits in the Jiaodong Peninsula were formed during the same mineralization event.

  6. Clasts petrography of post-glacial deposits in the Lubusz Elevation, western Poland

    NASA Astrophysics Data System (ADS)

    Lipka, Ewelina

    2010-05-01

    Clasts petrography of post-glacial deposits in the Lubusz Elevation, western Poland Ewelina Lipka Department of Geomorphology, Adam Mickiewicz University, Poznan, Poland This study presents petrographic composition of post-glacial deposits in the Lubusz Elevation. Also parent areas and possible general ice-flow directions of those deposits were determined on the basis of clasts petrography. This contribution concerns the Lubusz Elevation, located in western Poland. This area is situated within the range of the Poznan Phase, which is the second stage of the Weichselian Ice Sheet in Poland. The author aimed at revealing a spatial tendency in petrographic composition of post-glacial deposits that comprise the Poznan Phase marginal zone. This petrographic composition became also a basis to determine parent areas and possible general ice-flow directions of the analysed deposits. The data set was collected from post-glacial deposits of varied lithology (superficial glacial till and glaciofluvial deposits) across the Poznan Phase marginal zone (end moraine, hinterland and foreland). Gravels of 4-10 and 20-60 mm fractions of both glacial till and glaciofluvial deposits were petrographically analysed. Also indicator and statistical erratics were recognised within the 20-60 mm fraction. All analysed deposits, disregarding either place of their occurance (end moraine, hinterland or foreland) or lithology (glacial till or glaciofluvial deposits) were found to consist mainly of crystalline rocks. Among end moraine and hinterland deposits (apart from crystalline rocks) Palaeosoic limestones, Palaeosoic sandstones and flints are present in significant amounts. Foreland deposits consist mainly (beside crystalline rocks) of Palaeosoic sandstones and flints. More Palaeosoic sandstones and flints and less quartz grains were observed among 20-60 mm fraction gravels comparing to those of 4-10 mm fraction. Significant percentage of flints in all analysed samples was found remarkable. It

  7. Middle to Late Pleistocene coastal deposits of Eivissa (Western Mediterranean): Chronology and evolution.

    NASA Astrophysics Data System (ADS)

    Del Valle, Laura; Pomar, Francisco; Fornós, Joan J.; Gómez-Pujol, Lluís; Anechitei-Deacu, Valentina; Timar-Gabor, Alida

    2016-04-01

    This study deals with the sedimentary and stratigraphical description of Pleistocene deposits from seven coastal areas of Eivissa (Balearic Islands). Twenty two sedimentary facies have been described involving the succession of eolian, colluvial and edaphic environments. Carbonate sandstones, breccias and silty deposits are the main component of these sequences. Despite the extensive eolian systems outcropping along the coast of Eivissa, there are very few studies performed to chronological framework of these deposits. Luminescence measurements were carried out using an automated RisØ TL/OSL-DA-20 reader in the Luminescence Dating Laboratory of Babes-Bolyai University (Cluj-Napoca, Romania) under low intensity red light. OSL dating of nineteen eolian levels indicate that their deposition took place between the Middle and Late Pleistocene, establishing a paleoclimatic evolution of Eivissa Island since 755 ka to 70 Ka. Eolian activity in the Eivissa Island can be correlated with regression episodes which took place during cold periods associated with different isotopic stages, concretely the MIS 18, 16, 12, 10, 8, 6 and 4. Similar results have been obtained from many sites along the western Mediterranean Sea such as Mallorca (Pomar i Cuerda, 1979; Nielsen et al, 2004; Fornós et al, 2009), Sardinia (Andreucci et al, 2009; Pascucci et al, 2014), Liguria (Pappalardo et al., 2013). Keywords: Eolian dunes, Pleistocene, Climatic evolution, Eivissa. References - Andreucci, S.; Pascucci, V.; Murray, A. S.; Clemmensen, L. B. 2009. Late Pleistocene coastal evolution of San Giovanni di Sinis, west Sardinia (Western Mediterranean). Sedimentary Geology, 216: 104- 116 - Fornós, J.J.; Clemmensen, L.B.; Gómez-Pujol, L.; Murray, A. 2009. Late Pleistocene carbonate aeolianites on Mallorca, Western Mediterranean: a luminescence chronology. Quaternary Science reviews 28: 2697-2709. -Nielsen, K.A.; Clemmensen, L.B.; Fornós, J.J. 2004. Middle Pleistocene magnetostratigraphy and

  8. Methane in ground ice and frozen Quaternary deposits of Western Yamal

    NASA Astrophysics Data System (ADS)

    Vasiliev, A. A.; Streletskaya, I. D.; Melnikov, V. P.; Oblogov, G. E.

    2015-12-01

    The content and the genesis of methane in underground ice and frozen Quaternary sediments of Western Yamal is studied. The minimum concentration of methane in frozen Quaternary deposits was found for sand: 15-100 ppm V. The maximum concentration of methane reaches 3000 ppm V in marine clays. The concentration of methane in the ice wedges is 100-700 ppm V, and in the massive ground ice can be more than 10 000 ppm V. The high content of methane in the massive ground ice we explain by migration of methane from freezing deposits into ice body during its formation. The close connection between methane concentration and organic carbon content is found.

  9. Depositional sequences in a foreland basin (north-western domain of the continental Duero basin, Spain)

    NASA Astrophysics Data System (ADS)

    Herrero, Antonio; Alonso-Gavilán, Gaspar; Colmenero, Juan Ramón

    2010-01-01

    The Cenozoic record of the north-western domain of the Duero basin is articulated at the surface through a set of continental depositional sequences called, from base to top, the Vegaquemada sequence, the Candanedo sequence, and the Barrillos sequence. These depositional sequences were deposited in continental sedimentary environments. The deposition of the first sequence occurred through a fluvial system with floodplains cut by low-sinuosity channels. The Vegaquemada sequence was developed between the Middle Eocene and the Early Agenian. The second sequence was formed by a set of highly efficient transport alluvial fans that evolved laterally towards fluvial systems with low-sinuosity fluvial channels and an extensive floodplain, where several types of palaeosols were formed. This sequence developed between the Early Agenian and the Late Vallesian. The third unit-the Barrillos sequence (between the Late Vallesian and the Turolian/Ruscinian transition), was generated by a set of highly efficient transport alluvial fans dominated by low-sinuosity fluvial channels. In subsurface geology, seismic and well data are used to rebuild the stratigraphic architecture. The two basal depositional sequences can be identified with two seismic units: the Palaeogene Seismic Unit (PgSU) and the Neogene Seismic Unit (NgSU), respectively. In the present work, we obtained the isovelocity, isochron, and isobath maps for the top and base of the two Cenozoic units. The Palaeozoic (PzSU) and Mesozoic (MzSU) seismic units are found under these two units. Through study of the logs of the various boreholes, it was only possible to analyse the upper 700 m of the Candanedo Sequence (NgSU), without encompassing the total thickness of the unit. Several middle-order sequences were differentiated, in general showing a sequential fining-upwards evolutionary character. Additionally, for the boreholes analysed two main types of electrofacies were identified, both representing fluvial channels and

  10. Geological and geophysical characteristics of massive sulphide deposits: A case study of the Lirhanda massive sulphide deposit of Western Kenya

    NASA Astrophysics Data System (ADS)

    Dindi, E.; Maneno, J. B. J.

    2016-08-01

    An integrated geophysical ground survey was conducted on an airborne electromagnetic (EM) anomaly located in Kakamega forest of Western Kenya. The purpose of the study was to establish the existence of massive sulphides and identify suitable optimal geophysical method(s) for the investigation of similar anomalies. The study was also expected to provide information on the geological and geophysical characteristics of the deposit. Field work involved electromagnetic methods: Vertical Loop (VLEM), Horizontal Loop (HLEM), TURAM EM and potential field methods: gravity and magnetics. Geochemical sampling was carried out concurrently with the geophysical survey. All the geophysical methods used yielded good responses. Several conductors conforming to the strike of the geology were identified. TURAM EM provided a higher resolution of the conductors compared to VLEM and HLEM. The conductors were found to be associated with positive gravity anomalies supporting the presence of bodies of higher density than the horst rock. Only the western section (west of 625W) of the grid is associated with strong magnetic anomalies. East of 625W strong EM and gravity anomalies persist but magnetic anomalies are weak. This may reflect variation in the mineral composition of the conductors from magnetic to non-magnetic. Geochemical data indicates strong copper anomalies (upto 300 ppm) over sections of the grid and relatively strong zinc (upto 200 ppm) and lead (upto 100 ppm) anomalies. There is a positive correlation between the location of the conductors as predicted by TURAM EM and the copper and zinc anomalies. A test drill hole proposed on the basis of the geophysical results of this study struck massive sulphides at a depth of 30m still within the weathered rock zone. Unfortunately, the drilling was stopped before the sulphides could be penetrated. The drill core revealed massive sulphide rich in pyrite and pyrrhotite. An attempt has been made to compare characteristics of the

  11. Chapter F: Preliminary Bibliography of Lacustrine Diatomite Deposits in the Western United States and Related Topics

    USGS Publications Warehouse

    Bolm, Karen S.; Wallace, Alan R.; Moyle, Phillip R.; Bliss, James D.; Orris, Greta J.

    2003-01-01

    Introduction As part of the assessment of lacustrine diatomite resources in the Western United States (fig. 1), U.S. Geological Survey (USGS) project members conducted a review of literature relating to the formation, location, and nature of deposits in the study area. This preliminary bibliography consists of selected publications to identify, locate, and describe the deposits to be studied, to characterize common geologic factors about the deposits, and to better understand the factors that control their formation, preservation, or destruction. The bibliography also serves as a resource for other workers to research the topic. References included in the preliminary bibliography were gathered by searching existing bibliographic data bases and library collections. Project researchers also contributed references that they found during the course of their work. This bibliography should be considered a working document that will grow as research and literature searches continue. Clearly, many significant publications may be missing from this preliminary list; therefore, USGS staff members intend to issue a revised bibliography as project work progresses. To assure completeness, input from other researchers and industry is welcome. Although the focus of this bibliography is lacustrine diatomite deposits of the Western United States, additional references that provide a foundation of knowledge for the study of diatomites, diatoms, and diatom-related processes (ecology, geology, geochemistry) and for the uses and behavior of diatomite have also been included. An index of keywords has been added to this bibliography, designed to help the user locate reports by topic or by geographic location. The letter 'A' following a number indicates that the report referenced is an abstract.

  12. Distribution and sedimentary characteristics of tsunami deposits along the Cascadia margin of western North America

    USGS Publications Warehouse

    Peters, R.; Jaffe, B.; Gelfenbaum, G.

    2007-01-01

    Tsunami deposits have been found at more than 60 sites along the Cascadia margin of Western North America, and here we review and synthesize their distribution and sedimentary characteristics based on the published record. Cascadia tsunami deposits are best preserved, and most easily identified, in low-energy coastal environments such as tidal marshes, back-barrier marshes and coastal lakes where they occur as anomalous layers of sand within peat and mud. They extend up to a kilometer inland in open coastal settings and several kilometers up river valleys. They are distinguished from other sediments by a combination of sedimentary character and stratigraphic context. Recurrence intervals range from 300-1000??years with an average of 500-600??years. The tsunami deposits have been used to help evaluate and mitigate tsunami hazards in Cascadia. They show that the Cascadia subduction zone is prone to great earthquakes that generate large tsunamis. The inclusion of tsunami deposits on inundation maps, used in conjunction with results from inundation models, allows a more accurate assessment of areas subject to tsunami inundation. The application of sediment transport models can help estimate tsunami flow velocity and wave height, parameters which are necessary to help establish evacuation routes and plan development in tsunami prone areas. ?? 2007.

  13. Emission, Dispersion, Transformation, and Deposition of Asian Particulates Over the Western Pacific Ocean

    SciTech Connect

    Turco, Richard P.

    2005-02-28

    In this project we developed and applied a coupled three-dimensional meteorology/chemistry/microphysics model to study the patterns of aerosol dispersion and deposition in the western Pacific area; carried out a series of detailed regional aerosol simulations to test the ability of models to treat emission, dispersion and removal processes prior to long-range transport; calculated and analyzed trajectories that originate in Asian dust source regions and reach the Pacific Basin; performed detailed simulations of regional and trans-Pacific transport, as well as the microphysical and chemical properties, of aerosols in the Asia-Pacific region to quantify processes that control the emission, dispersion and removal of particles; and assessed the contributions of regional-scale Asian particulate sources to the deposition of pollutants onto surface waters. The transport and deposition of aerosols and vapors were found to be strongly controlled by large and synoptic scale meteorology, convection, turbulence, and precipitation, as well as strong interactions between surface conditions and topographical features. The present analysis suggests that accurate representations of aerosol sources, transport and deposition can be obtained using a comprehensive modeling approach.

  14. A characterisation of the coastal tufa deposits of south-west Western Australia

    NASA Astrophysics Data System (ADS)

    Forbes, Matt; Vogwill, Ryan; Onton, Kimberly

    2010-12-01

    Located in the south-west coastal zone of Western Australia are numerous tufa deposits, which are registered as Threatened Ecological Communities (TEC). The tufas occur in near-shore shallow bedrock settings and are associated with local groundwater discharge. Depositional facies, mineralogy, elemental chemistry and water quality were investigated for five key deposits. Two conceptual environmental models are identified. The first, the cascade to barrage pool model is associated with coastal waterfall zones, the second, a perched spring-line and barrage pool model is located predominantly in the supratidal zone. Tufa morphology, texture, mineral composition and elemental chemistry vary within and between sites. Both phytoclast and lithoclast (allochthonous), and phytoherm forms of tufa are identified depending on location within the facies. Calcite, and to a lesser extent, aragonite and Mg-calcite dominate tufa mineralogy, with diagenetic modifications apparent. Tufa water chemistry is generally Na-Cl-HCO 3 dominated; however, Na-Cl concentrations increase at sites situated within the supratidal zone. Currently the most likely potential threat posed to these deposits is increasing nutrient levels in spring waters from agricultural land use within the catchments. This could in the future impact on tufa development.

  15. Slope depositional processes along western Great Bahama Bank: A rapidly prograding carbonate platform

    SciTech Connect

    Wilber, R.J. ); Halley, R.B. ); Milliman, J.D. )

    1991-03-01

    The western margin of Great Bahama Bank has prograded rapidly into the Santaren Channel throughout Quaternary time. Platform growth is accomplished mainly by vigorous outbuilding of the slope - up to 500 m in the last 6-10 ka. Seismic stratigraphy and sediment and rock analysis reveal sharp contrasts in depositional facies and mechanisms of growth between the upper slope (50-160 m) and lower slope (160-600 m). The upper slope is steep (30-60{degree}) and rock with a thin (< 1 m) layer of coarse Halimeda sand. In situ sediment production, in combination with cementation by magnesium clacite, allows this interval to grow as a slowly accreting (meters/1,000 yr), lithified surface. Because of cementation, slope failure is rare but, in some areas, large blocks calved off the upper slope are found on the lower slope (mega-breccia). The lower slope is gentle (10-30{degree}) and consists of thick (up to 90 m) accumulations of fine bank-top sediment. Deposition occurs episodically via settling of sediment plumes swept off the bank during large storms. Lower slope deposits are absent where off-bank transport is barred by shelf-edge islands. In addition, hyperpycnal flows which cascade over the margin both sweep the upper slope and erode lower slope deposits near the depth of onlap. Slope failure in the uncemented lower slope deposits is primarily via slumping and possibly gravity flows. Lower slope deposition occurs only during sea level high stands when the rates of growth may be an order of magnitude higher than those of the upper slope which apparently experiences slow growth throughout most of a sea level cycle.

  16. Sichuan Earthquake in China

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Sichuan earthquake in China occurred on May 12, 2008, along faults within the mountains, but near and almost parallel the mountain front, northwest of the city of Chengdu. This major quake caused immediate and severe damage to many villages and cities in the area. Aftershocks pose a continuing danger, but another continuing hazard is the widespread occurrence of landslides that have formed new natural dams and consequently new lakes. These lakes are submerging roads and flooding previously developed lands. But an even greater concern is the possible rapid release of water as the lakes eventually overflow the new dams. The dams are generally composed of disintegrated rock debris that may easily erode, leading to greater release of water, which may then cause faster erosion and an even greater release of water. This possible 'positive feedback' between increasing erosion and increasing water release could result in catastrophic debris flows and/or flooding. The danger is well known to the Chinese earthquake response teams, which have been building spillways over some of the new natural dams.

    This ASTER image, acquired on June 1, 2008, shows two of the new large landslide dams and lakes upstream from the town of Chi-Kua-Kan at 32o12'N latitude and 104o50'E longitude. Vegetation is green, water is blue, and soil is grayish brown in this enhanced color view. New landslides appear bright off-white. The northern (top) lake is upstream from the southern lake. Close inspection shows a series of much smaller lakes in an elongated 'S' pattern along the original stream path. Note especially the large landslides that created the dams. Some other landslides in this area, such as the large one in the northeast corner of the image, occur only on the mountain slopes, so do not block streams, and do not form lakes.

  17. A multi-proxy palaeoecological and palaeoclimatic record within full glacial lacustrine deposits, western Tennessee, USA

    USGS Publications Warehouse

    Grimley, D.A.; Daniel, L.; Kaplan, S.W.; Yansa, C.H.; Curry, B. Brandon; Oches, E.A.

    2009-01-01

    The Fulton Section, along the Mississippi River in western Tennessee, USA, is a 1km continuous exposure (~20m vertically) of Quaternary fluvial and lacustrine deposits, inset within Eocene sediments and buried by thick loess. Fossiliferous slackwater lake sediments record maximum aggradation during the last two major glaciations, with deposition between ca. 190-140 ka and 24-1814C ka BP, based on amino acid and radiocarbon chronology, respectively. During the onset of full glacial conditions (ca. 24-22 14C ka BP), a relatively permanent shallow lake environment is indicated by ostracods, aquatic molluscs, and both pollen and macrofossils of aquatic plants. By 21.8 14C ka BP, increasing emergent plants, amphibious gastropods (Pomatiopsis) and heavier ??18O compositions suggest marsh-like conditions in a periodically drying lake. The surrounding uplands consisted of Picea-Pinus woodlands mixed with cool-temperate hardwoods (e.g. Quercus, Populus, Carya), grasses and herbs. More open conditions ensued ca. 20 14C ka BP, with loess and slopewash gradually infilling the former lake by 18 14C ka BP. Modern analogue analyses of ostracods and palaeontological evidence imply a full glacial climate similar to today's mixed-boreal zone in central Minnesota, USA, about 98C cooler in mean annual temperature than present-day western Tennessee. Copyright ?? 2009 John Wiley & Sons, Ltd.

  18. Geometry of the neoproterozoic and paleozoic rift margin of western Laurentia: Implications for mineral deposit settings

    USGS Publications Warehouse

    Lund, K.

    2008-01-01

    The U.S. and Canadian Cordilleran miogeocline evolved during several phases of Cryogenian-Devonian intracontinental rifting that formed the western mangin of Laurentia. Recent field and dating studies across central Idaho and northern Nevada result in identification of two segments of the rift margin. Resulting interpretations of rift geometry in the northern U.S. Cordillera are compatible with interpretations of northwest- striking asymmetric extensional segments subdivided by northeast-striking transform and transfer segments. The new interpretation permits integration of miogeoclinal segments along the length of the western North American Cordillera. For the U.S. Cordillera, miogeoclinal segments include the St. Mary-Moyie transform, eastern Washington- eastern Idaho upper-plate margin, Snake River transfer, Nevada-Utah lower-plate margin, and Mina transfer. The rift is orthogonal to most older basement domains, but the location of the transform-transfer zones suggests control of them by basement domain boundaries. The zigzag geometry of reentrants and promontories along the rift is paralleled by salients and recesses in younger thrust belts and by segmentation of younger extensional domains. Likewise, transform transfer zones localized subsequent transcurrent structures and igneous activity. Sediment-hosted mineral deposits trace the same zigzag geometry along the margin. Sedimentary exhalative (sedex) Zn-Pb-Ag ??Au and barite mineral deposits formed in continental-slope rocks during the Late Devonian-Mississippian and to a lesser degree, during the Cambrian-Early Ordovician. Such deposits formed during episodes of renewed extension along miogeoclinal segments. Carbonate-hosted Mississippi Valley- type (MVT) Zn-Pb deposits formed in structurally reactivated continental shelf rocks during the Late Devonian-Mississippian and Mesozoic due to reactivation of preexisting structures. The distribution and abundance of sedex and MVT deposits are controlled by the

  19. North-Atlantic millennial-timescale variability imprint on Western European loess deposits: a modeling study

    NASA Astrophysics Data System (ADS)

    Sima, A.; Rousseau, D.; Kageyama, M.; Ramstein, G.; Schulz, M.; Balkanski, Y.; Antoine, P.; Dulac, F.; Hatte, C.

    2008-12-01

    We test if the dust cycle response to the North-Atlantic abrupt climate changes, the Dansgaard-Oeschger (DO) and Heinrich (H) events, could have led to the recording of these events in the Western European loess deposits. The LMDZ AGCM is used to simulate a reference glacial state "DOS", assimilated to a DO stadial, a cold perturbation "HE", resembling a H event, and a warm perturbation "DOI", assimilated to a DO interstadial. The reference state corresponds to the 40-kyr BP context, in the middle of the typical glacial period (75-15 kyr BP). The two perturbations are obtained by applying cold, respectively warm anomalies of up to 2°C to the North-Atlantic surface temperatures in the latitudinal band 30°- 63°N. The simulated climates are compared from the point of view of dust emission, with a focus on the English Channel and the south of the North Sea (ECSNS), important dust sources for the Western European loess deposits. When only considering the changes in wind, precipitation, soil moisture and snow cover over the ECSNS and loess deposit areas, the differences of dust emission flux between the simulations are small, in contradiction with the observed stadial-interstadial loess sedimentation rate variations. However, when including the vegetation effect of inhibiting the eolian erosion, the three climates are clearly differentiated, the dust flux for DOI becoming less than half of that for DOS and HE. This shows that vegetation changes have played a key role in the stadial-interstadial dust cycle variations.

  20. Large-scale Crustal Features, Epithermal Gold Deposits, and the Yellowstone Hotspot, Western U.S.

    NASA Astrophysics Data System (ADS)

    Ponce, D. A.; Glen, J. M.

    2001-12-01

    Aeromagnetic and filtered magnetic maps of the western U.S. reveal at least 3 and up to 6 narrow, arcuate anomalies that form a radial pattern, the geometry of which suggests a unifying process. The most notable of these anomalies is the northern Nevada rift (NNRe), first identified as a high-amplitude, linear aeromagnetic anomaly extending from the Nevada-Oregon boarder for several hundred kilometers to the south-southeast. The NNRe anomaly is associated with a mid-Miocene mafic dike swarm, presumably emplaced along a narrow rift corridor and represents the mid-Miocene stress direction (Zoback, 1978; Zoback and others, 1994). Other similar, though less prominent geophysical anomalies occur to the west of the NNRe. With the aid of filtering and gradient analysis these anomalies, along with the NNRe appear to extend northward into Oregon and verge towards a common point. Numerous other geologic lineations, when extrapolated intersect at virtually the same location, suggesting that all these features radiate from a single point located along the Idaho-Oregon boarder at lat 44 oN (Glen and Ponce, 2000). A possible explanation for this pattern is a point stress at the base of the lithosphere related to the impact of the Yellowstone hotspot. Because the northern Nevada rift has been shown to correlate with mid-Miocene epithermal gold deposits along its trend (John and Wallace, 2000; John and others, 2000), we investigate the association of epithermal gold deposits to other similar arcuate features in northern Nevada. Mid-Miocene and younger epithermal gold-silver deposits also occur along two prominent aeromagnetic anomalies west of the northern Nevada rift and to three less prominent arcuate magnetic features. We speculate that mid-Miocene epithermal deposits formed along deep fractures associated with mid-Miocene rift-related magmatism, ultimately related to the inception of the Yellowstone hotspot, and that younger deposits preferentially followed these pre

  1. Geological characteristics and ore-forming process of the gold deposits in the western Qinling region, China

    NASA Astrophysics Data System (ADS)

    Liu, Jiajun; Liu, Chonghao; Carranza, Emmanuel John M.; Li, Yujie; Mao, Zhihao; Wang, Jianping; Wang, Yinhong; Zhang, Jing; Zhai, Degao; Zhang, Huafeng; Shan, Liang; Zhu, Laimin; Lu, Rukui

    2015-05-01

    The western Qinling, belonging to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block, is one of the most important gold regions in China. Isotopic dates suggest that the Mesozoic granitoids in the western Qinling region emplaced during the Middle-Late Triassic, and the deposits formed during the Late Triassic. Almost all gold deposits in the western Qinling region are classified as orogenic, Carlin-type, and Carlin-like gold deposits, and they are the products of Qinling Orogenesis caused by the final collision between the North China Block and the South China Block. The early subduction of the Mian-Lue oceanic crust and the latter collision between South Qinling Terrane and the South China Block along the Mian-Lue suture generated lithosphere-scale thermal anomalies to drive orogen-scale hydrothermal systems. The collision-related magmatism also provided heat source for regional ore-forming fluids in the Carlin-like gold deposits. Orogenic gold deposits such as Huachanggou, Liziyuan, and Baguamiao lie between the Shang-Dan and Mian-Lue sutures and are confined to WNW-trending brittle-ductile shear zones in Devonian and Carboniferous greenschist-facies metasedimentary rocks that were highly-deformed and regionally-metamorphosed. These deposits are typical orogenic gold deposits and formed within a Late Triassic age. The deposits show a close relationship between Au and Ag. Ores contain mainly microscopic gold, and minor electrum and visible gold, along with pyrite. The ore-forming fluids were main metamorphic fluids. Intensive tectonic movements caused by orogenesis created fluid-migrating channels for precipitation locations. Although some orogenic gold deposits occur adjacent to granitoids, mineralization is not synchronous with magmatism; that is, the granitoids have no genetic relations to orogenic gold deposits. As ore-forming fluids converged into dilated fractures during the extension stage of orogenesis

  2. Modeling study of North-Atlantic millennial-timescale variability imprint on Western European loess deposits

    NASA Astrophysics Data System (ADS)

    Sima, A.; Rousseau, D.-D.; Kageyama, M.; Ramstein, G.; Schultz, M.; Balkanski, Y.; Antoine, P.; Dulac, F.; Hatté, C.

    2009-04-01

    Studies on loess sequences of Western Europe have shown (i) that the loess sedimentation pattern over the last glaciation (approximately 100 to 15 thousand years before present (kyr BP)) has been very similar throughout the European loess belt, indicating a common climate control, and (ii) that the rapid environmental changes on the continent are correlated with the North-Atlantic millennial-timescale variations, the so-called Dansgaard-Oeschger (DO) and Heinrich (H) events. Here we test, by means of numerical modelling, if, and by which mechanisms, the dust cycle response to the environmental changes induced by the DO and H events could have led to the recording of these events in the loess deposits of the Western Europe. The LMDZ atmosphere general circulation model, in a version with a stretched grid enhancing the resolution over Western Europe to 60km, is used to simulate (a) a reference glacial state, assimilated to a DO stadial (DOS), (b) a cold perturbation over the North Atlantic, resembling a H event, and (c) a warm perturbation, assimilated to a DO interstadial (DOI). The reference state corresponds to the 40-kyr BP context, in the middle of the typical glacial period (approximately 75 to 15 kyr BP). The subsequent perturbations are obtained by applying cold or warm anomalies of up to 2°C in absolute value to the North-Atlantic sea-surface temperatures in the latitudinal band 30° - 63°N. The three simulated climate states are compared from the point of view of the initial driver of the dust cycle, the dust emission. A detailed analysis is provided for the English Channel and the south of the North Sea (ECSNS), important deflation areas in glacial times, and a source for the Western European loess deposits. In our experiments, the impact of altering the North-Atlantic surface conditions is weak over the ECSNS and loess areas (roughly, the latitudinal band 48° - 53°N) with respect to wind and precipitation. When only considering these factors, and the

  3. Supratidal beach deposits in Giralia Bay (Exmouth Gulf, Western Australia) - a record for past tropical cyclones?

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Gelhausen, Henrik; Brill, Dominik; Callow, Nik; Engel, Max; Scheffers, Anja; Joannes-Boyau, Renaud; Leopold, Matthias; Opitz, Stephan; Brückner, Helmut

    2016-04-01

    Past coastal flooding events related to tropical cyclones (TCs) and tsunamis may be inferred from geomorphic and sedimentary archives, i.e. in the form of particular landforms (beach ridges, washover fans), deposits (washover sediments in lagoons) or erosional features. In Giralia Bay, southern Exmouth Gulf (Western Australia), sandy ridge sequences in supratidal elevations form the landward margin of extensive mudflats. The formation of these ridges, as in other mudflats of NW Australia, is assumed to be mainly driven by TCs, although their relation to depositional processes and inundation levels during spring tide conditions, exceptional precipitation and discharge events, and storm surges needs to be clarified. Based on a simple process monitoring setup using a time-lapse camera and pressure gauges, geomorphological mapping by means of unmanned aerial vehicle survey and structure-from-motion techniques, as well as sedimentological and geochronological investigations, this study aims at (i) establishing the chronostratigraphy and reconstructing the formation of the supratidal beach deposits; (ii) identifying the most important driving processes involved in their formation; and (iii) understanding their significance for recording past TC activity. Sediment trenches cross the youngest, most seaward part of the ridge sequence. At the base of the sedimentary succession, sandy units are interbedded with mud layers, reflecting depositional conditions similar to the present distal mudflat. In the upper part of the ridges, mud intercalations recede, and sand layers of varying grain size distribution and mineralogical content dominate. Younger sediment layers clearly attach to older ones documenting the stepwise accretion of the ridges onto the mudflat. Muddy intercalations in the upper part of the succession are interpreted to represent deposition in locally restricted swales. Monitoring covered the time period between August 2013 and 2015 and capture an exceptional

  4. Triassic and Jurassic-Cretaceous deposits in the Western Chukotka: geodynamic implications, provenance studies and deformation

    NASA Astrophysics Data System (ADS)

    Tuchkova, M.

    2012-04-01

    Studied region is situated in western Chukotka, in Northeast Russia. We examine the part of Chukotka microplate, the key element in the evolution of the Amerasian basin. The Triassic of Chukotka is represented by up to 5 km of deposits. Triassic terrigeneous deposits consist of three different complexes: Lower-Middle Triassic, Upper Triassic Carnian, and Norian. All the complexes are represented by rhythmic intercalation of sandstones, siltstones and mudstones. Clastic material was carried by large rivers, possessing large reservoir on neighbouring continent. Progradation of delta system in deeper regions is observed. During the Triassic, sedimentation was represented by continental slope progradation. Petrographic study of mineral composition has established the sandstones as graywackes and lithic arenites, according to Pettijohn classification (1981). Sandstones with clasts of rock fragments of lower metamorphic grade rocks dominate at the base of Triassic deposits, sandstones with fragments of higher grade metamorphic rocks dominate in the Later Triassic deposits. This different shows that the Triassic represents an unroofing sequence sours of erosional processes that produced the clastic material eroded more deeply buried rocks through time. Detrital zircons from Triassic sedimentary rocks were collected for constain its paleogeographic links to source terranes. Zircons populations from these three samples are very similar, and youngest zircon ages show peaks at 236-255 Ma. Besides, we are dating the 9 samples for K-Ar and Rb-Sr methods. Data are similar and show 200-204 Ma, and we suppose that this isotopic data indicate the age of first stage of deformation in Chukotka's basin. The Jurassic-Cretaceous of Chukotka is represented by up to 3 km of deposits. The sedimentary complexes are enriched by organic matter, and fresh clastic materials. Fragments of shales, sometimes laminated or cleaved are their indicator constituents. Sandstones are arkosic. The

  5. A mid-Holocene candidate tsunami deposit from the NW Cape (Western Australia)

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Falvard, Simon; Norpoth, Maike; Pint, Anna; Brill, Dominik; Engel, Max; Scheffers, Anja; Dierick, Manuel; Paris, Raphaël; Squire, Peter; Brückner, Helmut

    2016-03-01

    Although extreme-wave events are frequent along the northwestern coast of Western Australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally, robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking. Based on the analyses of X-ray computed microtomography (μCT) of oriented sediment cores, multi-proxy sediment and microfaunal analyses, optically stimulated luminescence (OSL) and 14C-AMS dating, this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back-barrier depression on the NW Cape Range peninsula. The event layer consists of material from the adjacent beach and dune, fines and thins inland, and was traced up to ~ 400 m onshore. Although a cyclone-induced origin cannot entirely be ruled out, the particular architecture and fabric of the sediment, rip-up clasts and three subunits point to deposition by a tsunami. As such, it represents the first stratigraphical evidence of a prehistoric, mid-Holocene tsunami in NW Western Australia. It was OSL-dated to 5400-4300 years ago, thus postdating the regional mid-Holocene sea-level highstand.

  6. Increasing eolian dust deposition in the western United States linked to human activity

    NASA Astrophysics Data System (ADS)

    Neff, J. C.; Ballantyne, A. P.; Farmer, G. L.; Mahowald, N. M.; Conroy, J. L.; Landry, C. C.; Overpeck, J. T.; Painter, T. H.; Lawrence, C. R.; Reynolds, R. L.

    2008-03-01

    Mineral aerosols from dust are an important influence on climate and on marine and terrestrial biogeochemical cycles. These aerosols are generated from wind erosion of surface soils. The amount of dust emission can therefore be affected by human activities that alter surface sediments. However, changes in regional- and global-scale dust fluxes following the rapid expansion of human populations and settlements over the past two centuries are not well understood. Here we determine the accumulation rates and geochemical properties of alpine lake sediments from the western interior United States for the past 5,000 years. We find that dust load levels increased by 500% above the late Holocene average following the increased western settlement of the United States during the nineteenth century. We suggest that the increased dust deposition is caused by the expansion of livestock grazing in the early twentieth century. The larger dust flux, which persists into the early twenty-first century, results in a more than fivefold increase in inputs of K, Mg, Ca, N and P to the alpine ecosystems, with implications for surface-water alkalinity, aquatic productivity and terrestrial nutrient cycling.

  7. Spectral Mapping of Interior Layered Deposits of Western Candor Chasma by CRISM

    NASA Astrophysics Data System (ADS)

    Murchie, S.; Roach, L.; Milliken, R.; Seelos, F.; Wiseman, S.; Humm, D.; Mustard, J.; Bibring, J.; CRISM Team

    2007-12-01

    Western Candor Chasma contains a 3 km-thick sequence of interior layered deposits (ILDs) that may have been emplaced by sedimentary deposition subsequent to formation of Valles Marineris. Proposed genetic mechanisms include subaerial fluvial deposition or volcanism, accumulation of airfall dust, lacustrine evaporite precipitation, hydrovolcanism, or alternatively deep erosion of the chasma wall materials. Observations by the Mars Express/OMEGA spectrometer showed that the ILDs contain both monohydrated and polyhydrated sulfates in close spatial association with fine-grained ferric oxides having distinctive visible-infrared absorptions (Gendrin et al. 2005a,b). In general, OMEGA data also suggest that monohydrated sulfates are associated with steeper slopes and higher albedos than are polyhydrated sulfates (Mangold 2006). CRISM has observed the ILDs in western Candor using both its 200 m/pixel global mapping mode and targeted observations at 20 or 40 m/pixel. CRISM data show spatial heterogeneity in spectral properties to the spatial resolution limit of the instrument. Both monohydrated sulfates (indicated by 2130- and 2400-nm absorptions) and polyhydrated sulfates (indicated by 1450-, 1940-, and 2420-nm absorptions) are evident at all elevations in the ILDs. Polyhydrate signatures occur on intermediate-albedo, relatively intact exposures of stratified material and are rare, but not absent, in nearby erosional debris. Typically the polyhydrate outcrops are low-sloped and form erosion-resistant cap rocks. The monohydrated sulfate also occurs in intermediate- to high-albedo outcrops, but is more commonly distributed as dark, erosional debris on ledges and in depressions that has been modified by wind to form dunes. Only in rare cases can the dark debris be associated with a discrete, dark source layer. The erosional debris exhibits enhancements in sulfate absorptions as well as in 530-, 660-, and 860- to 900-nm absorptions due to ferric iron minerals; different debris

  8. The boron isotope geochemistry of the Kirka borate deposit, western Turkey

    NASA Astrophysics Data System (ADS)

    Palmer, M. R.; Helvaci, C.

    1995-09-01

    We have measured the boron isotope composition of seventeen samples of borate minerals (colemanite, ulexite, and borax) and the 87Sr/ 86Sr ratio in thirteen borate samples from the Kirka borate deposit in western Anatolia, Turkey. These Neogene deposits were formed by evaporation of playa lakes fed by geothermal springs. The δ 11B values range from -14.9% o in colemanite to -1.6% o in borax. To a first approximation the relative differences in the δ 11B values of the borate minerals are consistent with their basic boron atomic configuration, but the magnitude of the boron isotope fractionation between the three minerals precludes their simultaneous precipitation from a brine with the same boron isotope composition and pH. Rather the data are consistent with precipitation of colemanite from a brine with lower pH than that required for ulexite precipitation, which in turn requires a lower pH than is needed for borax precipitation. The boron isotope data also suggest that the borate minerals did not maintain boron isotopic equilibrium with the brine after they precipitated. Rayleigh fractionation models indicate that during borax precipitation the δ 11B value of the brine was slightly heavier than during precipitation of ulexite and colemanite.

  9. Mineralogical characteristics of the superlarge Quaternary bauxite deposits in Jingxi and Debao counties, western Guangxi, China

    NASA Astrophysics Data System (ADS)

    Liu, Xuefei; Wang, Qingfei; Zhang, Qizuan; Feng, Yuewen; Cai, Shuhui

    2012-06-01

    In recent decades, more than 0.5 billion tons of ores scattered in the Quaternary laterite in western Guangxi, China have been explored. The ores were derived from a bauxite horizon in Permian via physical break-up and re-sediment process. Utilizing various test methods, i.e., XRD, DTA, TG/DTG, SEM/EDS and EPMA, the mineralogical characteristics of the Quaternary bauxite ores in Jingxi and Debao counties were investigated. XRD was used together with TG/DTG to obtain relatively accurate ore mineral abundance. Diaspore is the major phase, whereas hematite, kaolinite, anatase, chamosite, gibbsite, goethite, illite and rutile are minor. Diaspore is characterized by a small particle size, low degrees of crystallinity and complex chemical composition. Both gibbsite and goethite have a varied particle size, and goethite crystals contain high Al substitution and Si. It is clarified that diaspore, chamosite and anatase were formed in a mildly reduced and alkaline depositional environment in Permian, while gibbsite, hematite, goethite and part kaolinite were precipitated from Al3+-, Si4+- and Fe3+-enriched solutions within an Quaternary oxidized environment. The ions Al3+, Si4+ and Fe3+ are mostly released from chamosite in its dissolution process. The different physicochemical conditions between the Permian depositional and the Quaternary weathering periods resulted in a complex mineral assemblage in the Quaternary bauxite.

  10. Linked sequence stratigraphy and tectonics in the Sichuan continental foreland basin, Upper Triassic Xujiahe Formation, southwest China

    NASA Astrophysics Data System (ADS)

    Li, Yingjiao; Shao, Longyi; Eriksson, Kenneth A.; Tong, Xin; Gao, Caixia; Chen, Zhongshu

    2014-07-01

    Intracontinental subduction of the South China Block below the North China Block in the Late Triassic resulted in formation of the transpressional Sichuan foreland basin on the South China Block. The Upper Triassic Xujiahe Formation was deposited in this basin and consists of an eastward-tapering wedge of predominantly continental siliciclastic sedimentary rocks that are up to 3.5 km thick in the western foredeep depocenter and thin onto the forebulge and into backbulge depocenters. Five facies associations (A-E) make up the Xujiahe Formation and these are interpreted, respectively, as alluvial fan, transverse and longitudinal braided river, meandering river, overbank or shallow lacustrine, and deltaic deposits. This study establishes a sequence stratigraphic framework for the Xujiahe Formation which is subdivided into four sequences (SQ1, 2, 3 and 4). Sequence boundaries are recognized on the basis of facies-tract dislocations and associated fluvial rejuvenation and incision, and systems tracts are identified based on their constituent facies associations and changes in architectural style and sediment body geometries. Typical sequences consist of early to late transgressive systems tract deposits related to a progressive increase in accommodation and represented by Facies Associations A, B and C that grade upwards into Facies Association D. Regionally extensive and vertically stacked coal seams define maximum accommodation and are overlain by early highstand systems tract deposits represented by Facies Associations D, E and C. Late highstand systems tract deposits are rare because of erosion below sequence boundaries. Sequence development in the Xujiahe Formation is attributed to active and quiescent phases of thrust-loading events and is closely related to the tectonic evolution of the basin. The Sichuan Basin experienced three periods of thrust loading and lithospheric flexure (SQ1, lower SQ2 and SQ3), two periods of stress relaxation and basin widening (upper

  11. Shallow-water marl-limestone alternations in the Late Jurassic of western France: Cycles, storm event deposits or both?

    NASA Astrophysics Data System (ADS)

    Colombié, Claude; Schnyder, Johann; Carcel, Damien

    2012-10-01

    The contribution of event deposits to various basin fills can be very significant, higher than 90% in some cases. Events may lead to the formation of marl-limestone alternations, which can also result from cyclic changes in sea level or climate, for example. The marl-limestone alternations of the Late Jurassic of western France contain abundant coarse-grained accumulations that resemble storm deposits described in other western European successions. The detailed analysis of facies evolution and hierarchical, high-frequency stacking pattern of depositional sequences of the Phare de Chassiron section (Ile d'Oléron, western France) allows the controls on marl-limestone formation to be defined. This section contains nearshore and shallow-marine mud deposits that were exposed to high-energy events. Elementary, small-, and medium-scale depositional sequences are defined. The stacking-pattern and the duration of these sequences suggest an orbital control on sedimentation. Precession (20 ka) cycles notably controlled the formation of elementary sequences that correspond to marl-limestone alternations. The deposition of marly or carbonate mud occurred in this storm-dominated system because of muddy sea beds, the gentle slope of the shelf, and the great amount of particles in suspension, which reduced water energy resulting from storms. Sediment supply was also sufficient to limit bioturbation and favour the preservation of numerous storm deposits. The production of carbonate mud was localised on positive structures and partly controlled by Milankovitch-scale sea-level cycles. Transport by storms of carbonate mud to the adjacent marly depressions during high carbonate production periods led to the formation of calcareous beds. Marl-limestone alternations in the Late Jurassic of western France therefore result from the combined effects of cyclic changes in carbonate production and high-energy, episodic events.

  12. Geology and geochemistry of telluride-bearing Au deposits in the Pingyi area, Western Shandong, China

    NASA Astrophysics Data System (ADS)

    Hu, H.-B.; Mao, J.-W.; Niu, S.-Y.; Li, Y.-F.; Li, M.-W.

    2006-07-01

    Telluride-bearing gold deposits of the Pingyi area, western Shandong, China, are located on the southeastern margin of the North China Craton. There are two main types of deposits: (i) mineralized cryptoexplosive breccia, e.g., Guilaizhuang; and (ii) stratified, finely-disseminated mineralization hosted in carbonate rocks, e.g., Lifanggou and Mofanggou deposits. In Guilaizhuang, the cryptoexplosive breccia is formed within rocks of the Tongshi complex and Ordovician dolomite. The mineralization is controlled by an E-W-trending listric fault. Stratified orebodies of the Lifanggou and Mofanggou deposits are placed along a NE-trending, secondary detachment zone. They are hosted within dolomitic limestone, micrite and dolomite of the Early-Middle Cambrian Changqing Group. The mineralization in the ore districts is considered to be related to the Early Jurassic Tongshi magmatic complex that formed in a continental arc setting on the margin of the North China Craton. The host rocks are porphyritic and consist predominantly of medium- to fine-grained diorite and pyroxene (hornblende)-bearing monzonite. SHRIMP U-Pb zircon dating of diorites give a 206Pb/238U weighted mean age of 175.7 ± 3.8 Ma. This is interpreted as representing the crystallization age of the Tongshi magmatic complex. Considering the contact relationships between the magmatic and host sedimentary rocks, as well as the genetic link with the deposits, we conclude that this age is relevant also for the formation of mineralization in the Pingyi area. We hence consider that the deposits formed in the Jurassic. The principal gold minerals are native gold, electrum and calaverite. Wall-rock alteration comprises pyritization, fluoritization, silicification, carbonatization and chloritization. Fluid inclusion studies indicate that all the analyzed inclusions are of two-phase vapor-liquid NaCl-H2O type. Homogenization temperatures of the fluid inclusions vary from 103 °C to 250 °C, and the ice melting

  13. Rhinocerotidae from the Upper Miocene deposits of the Western Pannonian Basin (Hungary): implications for migration routes and biogeography

    NASA Astrophysics Data System (ADS)

    Pandolfi, Luca; Gasparik, Mihály; Magyar, Imre

    2016-02-01

    Although the rhinoceros remains have high biochronological significance, they are poorly known or scarcely documented in the uppermost Miocene deposits of Europe. Several specimens collected from the Upper Miocene (around 7.0 Ma, Turolian) deposits of Kávás (Pannonian Basin, Western Hungary), previously determined as Rhinoceros sp., are revised and described in this paper. The postcranial remains of these specimens belong to "Dihoplus" megarhinus (de Christol) on the basis of the morphological and morphometric characters of humerus, radii, metacarpal and metatarsal elements. An overview of rhinoceros remains from several uppermost Miocene localities and the revision of the rhinoceros material from the Pannonian Basin suggest that "D." megarhinus spread during the latest Miocene from the Pannonian Basin towards Italy. The occurrences of this species in Western Hungary and Italy during the latest Miocene further imply that Rhinocerotini species were biogeographically segregated between Western, Southern and Central Europe.

  14. Late Quaternary Depositional History and Anthropogenic Impacts of Western Long Island Sound, New York

    NASA Astrophysics Data System (ADS)

    McHugh, C. M.; Cormier, M.; Marchese, P.; Zheng, Y.; Stewart, G.; Acosta, V.; Bowman, A.; Cortes, A.; Leon, L.; Rosa, M.; Semple, D.; Thaker, N.; Vargas, W.; Williams, L.

    2006-12-01

    In June 2006, we surveyed the seafloor of western Long Island Sound with the R/V HUGH SHARP and collected multibeam bathymetry, chirp subbottom profiling, side-scan sonar imagery, and sediment samples (25 gravity cores, 11 multicores, and 10 grabs). In addition, 36 CTD hydrocast stations measured O, pH, alkalinity, trace metals, nutrients, Polonium-210, Lead-210, Thorium-234, organic carbon, and pigments. Continuous weather measurements, and water column properties using both CTD casts and a towed Scanfish were also carried out. Biological sampling included benthic grabs and plankton nets. The National Science Foundation under the "Opportunities to Enhance Diversity in the Geosciences" Program funded this one-week survey. Nine students from underrepresented groups in the geosciences and five P.I.'s participated in the field program. The major scientific objectives were to study the deglaciation of the Laurentide Ice Sheet and Holocene transgression of sea level to document age, sedimentation processes, and climate, and the impact of anthropogenic activities in the sediments, biota, and waters of the estuary. A deep (35 m) and narrow (< 1km) channel incised into bedrock characterizes the East River section of western Long Island Sound. In contrast, thick sedimentary deposits characterize the eastern part of the study area, 20 to 45 km east of New York City. Subbottom penetration reached in some instances 40 m, but is limited to less than 5 m where sediments are gas-charged. Four seismic sequences are imaged in the chirp records that we interpret to span the Last Glacial Maximum to Present: strong irregular erosional surfaces beneath parallel seismic reflectors are interpreted as glacial erosional surface and/or moraines, and as Glacial lake Connecticut sediments ~25 m thick, respectively. A thin veneer (<1 m) of acoustically transparent sediment is interpreted as recent deposits. It overlays a roughly 15 m thick unit interpreted as Holocene transgressive marine

  15. A few Issues about Wenchuan earthquake of 2008, Sichuan, China

    NASA Astrophysics Data System (ADS)

    Cao, J.; Liu, S.; Lu, Z.; Fu, Y.

    2008-12-01

    A devastating earthquake of magnitude 8.0, named Wenchuan earthquake, struck China's Sichuan province on May 12, 2008. The rupture occurred over a length of about 300 km along the northeast-striking Longmen Shan thrust belt. The earthquake resulted in huge casualties and property losses at Longmen Shan region of Sichuan Province, the Southern Shaanxi and Southern Gansu, more than 80,000 people were killed. Longmen Shan is the convergent margin of the eastern Tibetan plateau and Yangtze block. However the area has numerous geological features not typical of active convergent mountain belts. After the earthquake, lots of opinions have been expressed. Basing on field investigation and analysis, we put forward the following opinions: (1) the causative structure of the earthquake may be Pengguan fault, not the Beichuan-Yingxiu fault (central fault)£»(2) the uplift of the Longmen Shan and the earthquakes in Longmen Shan may be controlled by the bilateral stresses from the Songpan -Ganzi block on the west side and Sichuan basin on the east side; (3) by calculating the balance between the accumulation and dissipation of the compressed strain energy, we may make out an estimation of the rhythm of strong Earthquake in Longmen Shan; (4) By analyzing the pressure data measured at oil or gas producing wells, we may monitor the changes of the earth stress in deep; (5) Earthquakes in Longmen Shan may be favorable to the forming of the fractured reservoir and hydrocarbon accumulation in Western Sichuan depression. The work was supported by NSFC under grant No.40739907

  16. Nitrogen deposition to lakes in national parks of the western Great Lakes region: Isotopic signatures, watershed retention, and algal shifts

    NASA Astrophysics Data System (ADS)

    Hobbs, William O.; Lafrancois, Brenda Moraska; Stottlemyer, Robert; Toczydlowski, David; Engstrom, Daniel R.; Edlund, Mark B.; Almendinger, James E.; Strock, Kristin E.; VanderMeulen, David; Elias, Joan E.; Saros, Jasmine E.

    2016-03-01

    Atmospheric deposition is a primary source of reactive nitrogen (Nr) to undisturbed watersheds of the Great Lakes region of the U.S., raising concerns over whether enhanced delivery over recent decades has affected lake ecosystems. The National Atmospheric Deposition Program (NADP) has been measuring Nr deposition in this region for over 35 years. Here we explore the relationships among NADP-measured Nr deposition, nitrogen stable isotopes (δ15N) in lake sediments, and the response of algal communities in 28 lakes situated in national parks of the western Great Lakes region of the U.S. We find that 36% of the lakes preserve a sediment δ15N record that is statistically correlated with some form of Nr deposition (total dissolved inorganic N, nitrate, or ammonium). Furthermore, measured long-term (since 1982) nitrogen biogeochemistry and inferred critical nitrogen loads suggest that watershed nitrogen retention and climate strongly affect whether sediment δ15N is related to Nr deposition in lake sediment records. Measurements of algal change over the last ~ 150 years suggest that Nr deposition, in-lake nutrient cycling, and watershed inputs are important factors affecting diatom community composition, in addition to direct climatic effects on lake physical limnology. The findings suggest that bulk sediment δ15N does reflect Nr deposition in some instances. In addition, this study highlights the interactive effects of Nr deposition and climate variability.

  17. Radiostratigraphic study of the deposits of the Maikop Group, Western Azerbaijan

    NASA Astrophysics Data System (ADS)

    Efendieva, M.; Babaev, R.; Johnson, C.; Feyzullayev, A.; Aliev, Ch.

    2012-11-01

    This work presents the results of biostratigraphic study of natural outcrops of the Maikop Group, which were first carried together with detailed radiometric studies in the Ganja oil and gas-bearing region, Western Azerbaijan. The paleontological research method included determination of the genus or species (depending on the preservation) of microfaunistic remains (foraminifera, ostracods, fish remains). The radiometric research method included measurements of the integral radioactivity in the field, the sampling, as well as laboratory radionuclide (spectral) analysis. As a result of our research, the stratigraphic control of variation in the radioactivity of rocks of the Maikop Group of the Ganja oil and gas-bearing region has been established. The radioactivity of Oligocene rocks is predominantly determined by potassium content. The radioactivity of the Miocene part of the section of the Maikop Group is determined by uranium-potassium contents. Within the Ganja oil and gas-bearing region, deposits of the Kotsakhurian regional stage, which are usually referred to "barren" formations or anoxic "fish facies", contain a significant number of species of benthic foraminiferal fauna.

  18. Pliocene-Pleistocene continental deposits in western Kentucky: A new look at regional stratigraphy and depositional history

    SciTech Connect

    Phillips, B.E. )

    1992-01-01

    Pliocene and Pleistocene age sediments of the northernmost Mississippi Embayment consist of a thick sequence of continental deposits which rest unconformably on Cretaceous through Eocene strata. The continental deposits have been tentatively correlated to the Pliocene Mounds Gravel and Pleistocene Henry and Equality Formations of southern Illinois. These sediments have previously been interpreted as representing alluvial fan and fluvial deposits. The continental deposits are generally divided into three lithofacies: (1) silt/clay dominated; (2) sand dominated, and (3) gravel dominated. A subsurface study utilizing approximately 300 soil borings has shown that (1) the continental deposits, particularly the gravel facies, exhibit significant local changes in thickness, (2) the upper portion of the sequence consists predominantly of finer-grained silt/clay lithofacies, and (3) sand and gravel lithofacies within the upper sequence often occur at predictable horizons. These observations indicate a paleovalley fill with distinct depositional episodes. As a result of Pleistocene base level fluctuations, stream systems became deeply entrenched in the Pliocene alluvial fan and older sediments. Fan deposits were initially transported and redeposited in a braided fluvial system. As valley alluviation continued and gradients decreased, the braided fluvial system evolved into a meandering system. During Woodfordian time, slackwater lakes created by glacial outwash dams produced extensive lacustrine deposits. At least two major episodes of lacustrine sedimentation are apparent. Significant fluctuations of lake level are recognized in the subsurface by local erosional surfaces overlain by coarser-grained sediments deposited in basinward-migrating channel and shoreline facies.

  19. Inorganic nitrogenous air pollutants, atmospheric nitrogen deposition and their potential ecological impacts in remote areas of western North America (Invited)

    NASA Astrophysics Data System (ADS)

    Bytnerowicz, A.; Fenn, M. E.; Fraczek, W.; Johnson, R.; Allen, E. B.

    2013-12-01

    Dry deposition of gaseous inorganic nitrogenous (N) air pollutants plays an important role in total atmospheric N deposition and its ecological effects in the arid and semi-arid ecosystems. Passive samplers and denuder/ filter pack systems have been used for determining ambient concentrations of ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), and nitric acid vapor (HNO3) in the topographically complex remote areas of the western United States and Canada. Concentrations of the measured pollutants varied significantly between the monitoring areas. Highest NH3, NO2 and HNO3 levels occurred in southern California areas downwind of the Los Angeles Basin and in the western Sierra Nevada impacted by emissions from the California Central Valley and the San Francisco Bay area. Strong spatial gradients of N pollutants were also present in southeastern Alaska due to cruise ship emissions and in the Athabasca Oil Sands Region in Canada affected by oil exploitation. Distribution of these pollutants has been depicted by maps generated by several geostatistical methodologies within the ArcGIS Geostatistical Analyst (ESRI, USA). Such maps help to understand spatial and temporal changes of air pollutants caused by various anthropogenic activities and locally-generated vs. long range-transported air pollutants. Pollution distribution maps for individual N species and gaseous inorganic reactive nitrogen (Nr) have been developed for the southern portion of the Sierra Nevada, Lake Tahoe Basin, San Bernardino Mountains, Joshua Tree National Park and the Athabasca Oil Sands Region. The N air pollution data have been utilized for estimates of dry and total N deposition by a GIS-based inferential method specifically developed for understanding potential ecological impacts in arid and semi-arid areas. The method is based on spatial and temporal distribution of concentrations of major drivers of N dry deposition, their surface deposition velocities and stomatal conductance values

  20. Depositional settings, correlation, and age carboniferous rocks in the western Brooks Range, Alaska

    USGS Publications Warehouse

    Dumoulin, J.A.; Harris, A.G.; Blome, C.D.; Young, L.E.

    2004-01-01

    The Kuna Formation (Lisburne Group) in northwest Alaska hosts the Red Dog and other Zn-Pb-Ag massive sulfide deposits in the Red Dog district. New studies of the sedimentology and paleontology of the Lisburne Group constrain the setting, age, and thermal history of these deposits. In the western and west-central Brooks Range, the Lisburne Group includes both deep- and shallow-water sedimentary facies and local volcanic rocks that are exposed in a series of thrust sheets or allochthons. Deep-water facies in the Red Dog area (i.e., the Kuna Formation and related rocks) are found chiefly in the Endicott Mountains and structurally higher Picnic Creek allochthons. In the Red Dog plate of the Endicott Mountains allochthon, the Kuna consists of at least 122 m of thinly interbedded calcareous shale, calcareous spiculite, and bioclastic supportstone (Kivalina unit) overlain by 30 to 240 m of siliceous shale, mudstone, calcareous radiolarite, and calcareous lithic turbidite (Ikalukrok unit). The Ikalukrok unit in the Red Dog plate hosts all massive sulfide deposits in the area. It is notably carbonaceous, is generally finely laminated, and contains siliceous sponge spicules and radiolarians. The Kuna Formation in the Key Creek plate of the Endicott Mountains allochthon (60-110 m) resembles the Ikalukrok unit but is unmineralized and has thinner carbonate layers that are mainly organic-rich dolostone. Correlative strata in the Picnic Creek allochthon include less shale and mudstone and more carbonate (mostly calcareous spiculite). Conodonts and radiolarians indicate an age range of Osagean to early Chesterian (late Early to Late Mississippian) for the Kuna in the Red Dog area. Sedimentologic, faunal, and geochemical data imply that most of the Kuna formed in slope and basin settings characterized by anoxic or dysoxic bottom water and by local high productivity. Shallow-water facies of th e Lisburne Group in the Red Dog area are present locally in the Endicott Mountains

  1. Critical nitrogen deposition loads in high-elevation lakes of the western US inferred from paleolimnological records

    USGS Publications Warehouse

    Saros, J.E.; Clow, D.W.; Blett, T.; Wolfe, A.P.

    2011-01-01

    Critical loads of nitrogen (N) from atmospheric deposition were determined for alpine lake ecosystems in the western US using fossil diatom assemblages in lake sediment cores. Changes in diatom species over the last century were indicative of N enrichment in two areas, the eastern Sierra Nevada, starting between 1960 and 1965, and the Greater Yellowstone Ecosystem, starting in 1980. In contrast, no changes in diatom community structure were apparent in lakes of Glacier National Park. To determine critical N loads that elicited these community changes, we modeled wet nitrogen deposition rates for the period in which diatom shifts first occurred in each area using deposition data spanning from 1980 to 2007. We determined a critical load of 1.4 kg N ha-1 year-1 wet N deposition to elicit key nutrient enrichment effects on diatom communities in both the eastern Sierra Nevada and the Greater Yellowstone Ecosystem. ?? 2010 Springer Science+Business Media B.V.

  2. Volatile element isotopes of submarine hydrothermal mineral deposits in the Western Pacific

    NASA Astrophysics Data System (ADS)

    Ooki, Mitsuhiro; Kagoshima, Takanori; Takahata, Naoto; Ishibashi, Jun-ichiro; Lan, Tefang; Guo, Zhengfu; Sano, Yuji

    2016-06-01

    The abundance and isotopic compositions of volatile elements trapped in fluid inclusions of submarine hydrothermal mineral deposits in Western Pacific subduction zones (Okinawa Trough, Izu-Bonin arc, Mariana Trough, and Lau Basin) and in Kuroko ores in northeastern Japan are presented. The helium isotopic compositions corrected for air contribution of the Okinawa and Mariana troughs, ranging 4.49-7.68 Ra are lower than those of the Izu-Bonin and Lau Basin, 7.62-8.91 Ra. This characteristic might reflect the differences in regional tectonic setting. The Okinawa and Mariana troughs are related to back-arc spreading with strong graben sedimentary signature, whereas the Izu-Bonin arc is associated with island arc magmatism. The arc contribution to the Lau Basin volcanism is significantly strong, even though it is assigned to back-arc spreading. Nitrogen isotopes can also be explained by a similar hypothesis, whereas argon and carbon isotopes cannot be used to discriminate tectonic setting. δ13C-CO2/3He and δ15N-N2/36Ar diagrams elucidate the source of carbon and nitrogen. The MOR-type mantle contributions to carbon are mostly smaller in the Okinawa and Mariana troughs (ranging 0.06-8.9% with the average of 2.4%) than in the Izu-Bonin and Lau Basin (2.1-25% with the average of 7.7%). The sedimentary contributions to nitrogen are larger in the Okinawa and Mariana troughs (11-65% with the average of 35%) than in the Izu-Bonin and Lau Basin (4-24% with the average of 15%), and the Kuroko samples agree well with the latter. Carbon and nitrogen fluxes are again higher in Okinawa trough than in Izu-Bonin arc.

  3. Hydrothermal fluids circulation and travertine deposition in an active tectonic setting: Insights from the Kamara geothermal area (western Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Brogi, Andrea; Alçiçek, M. Cihat; Yalçıner, Cahit Çağlar; Capezzuoli, Enrico; Liotta, Domenico; Meccheri, Marco; Rimondi, Valentina; Ruggieri, Giovanni; Gandin, Anna; Boschi, Chiara; Büyüksaraç, Aydin; Alçiçek, Hülya; Bülbül, Ali; Baykara, Mehmet Oruç; Shen, Chuan-Chou

    2016-06-01

    Coexistence of thermal springs, travertine deposits and tectonic activity is a recurring feature for most geothermal areas. Although such a certainty, their relationships are debated mainly addressing on the role of the tectonic activity in triggering and controlling fluids flow and travertine deposition. In this paper, we present the results of an integrated study carried out in a geothermal area located in western Anatolia (Turkey), nearby the well-known Pamukkale area (Denizli Basin). Our study focused on the relationships among hydrothermal fluids circulation, travertine deposition and tectonic activity, with particular emphasis on the role of faults in controlling fluids upwelling, thermal springs location and deposition of travertine masses. New field mapping and structural/kinematics analyses allowed us to recognize two main faults systems (NW- and NE-trending), framed in the Neogene-Quaternary extensional tectonic evolution of western Anatolia. A geo-radar (GPR) prospection was also provided in a key-area, permitting us to reconstruct a buried fault zone and its relationships with the development of a fissure-ridge travertine deposit (Kamara fissure-ridge). The integration among structural and geophysical studies, fluids inclusion, geochemical, isotopic data and 230 Th/238 U radiometric age determination on travertine deposits, depict the characteristics of the geothermal fluids and their pathway, up to the surface. Hydrological and seismological data have been also taken in account to investigate the relation between local seismicity and fluid upwelling. As a main conclusion we found strict relationships among tectonic activity, earthquakes occurrence, and variation of the physical/chemical features of the hydrothermal fluids, presently exploited at depth, or flowing out in thermal springs. In the same way, we underline the tectonic role in controlling the travertine deposition, making travertine (mainly banded travertine) a useful proxy to reconstruct the

  4. Geomorphology and regional stratigraphic model of Cenozoic deposits from "Continental to Marine" of Western Peninsular Malaysia and Strait of Malacca.

    NASA Astrophysics Data System (ADS)

    Menier, David; Mansor, Yazid; Sautter, Benjamin; Pubellier, Manuel; Estournes, Guilhem; Meng Choong, Chee; Ghosh Deva, Prasad; Proust, Jean-Noel; Goubert, Evelyne

    2014-05-01

    Coastal basins have been greatly influenced worldwide by their geological heritage (lithology, structural control) and eustatic sea-level fluctuations. Along the western side of Peninsular Malaysia, both the structures of the tertiary-quaternary basement and the geomorphology are poorly known. The coast is characterized landward by an absence of tertiary deposits on the alluvial and coastal plains and seaward by numerous deeply incised valleys although the incision potential is low. Offshore, in the Strait of Malacca, the thickness of sediments increases drastically, particularly at the apex of some N-S elongated basins (> 2 Km), and in the central part of the Strait of Malacca. Onshore, the geomorphology of the Western Peninsular Malaysia is controlled mostly by climatic effects on an old (Indosinian) orogen affected by transtensional brittle tectonics during the Tertiary. We investigate the effects of Tertiary extension and associated vertical motions on the Cenozoic geomorphology and stratigraphy. The study is based on a combined morphobathymetric approach of based on GEBCO data, supported by low and recent high resolution offshore seismic data, and DTM data from ASTER and SRTM. The main results are the followings: (1) the structural control appears to be responsible of the positioning and preservation of the Tertiary deposits; while the Quaternary (marine) deposits thinner, drowned the western Malaysia Peninsular coast, independently of the geomorphological and structural context; (2) The offshore Tertiary deposits seem disconnected from the modern drainage network, suggesting probable uplift during the late Tertiary period, which reactivated NW-SE trending faults and fractures; (3) The orientation, the shape and the depth of the ancient and modern incised valleys (Perak, Kerian , Kinta rivers) are controlled by the structural context and lithological contrast; (4) Finally, from a landward to a seaward directions, the Cenozoic deposits seems to have transited

  5. Geologic Setting of the May 12, 2008, Sichuan Earhquake

    NASA Astrophysics Data System (ADS)

    Burchfiel, B. C.; Royden, L. H.

    2008-12-01

    The May 12, 2008, Sichuan earthquake was located in the Longmen Shan, mountains that form the eastern margin of the Tibetan plateau and border the western side of the Sichuan basin. The region of the Longmen Shan consists of very complex structures that vary greatly along strike. Geologically, the Longmen Shan lie along the western margin of the Yangtze craton and was first deformed in late Triassic-early Jurassic (Indosinian) time when the margin was telescoped by large scale eastward thrusting and development of an adjacent Mesozoic foredeep. These units can be followed from their join with the Qinling Mountains in the north, south into central Yunnan. Although there are suggestions of younger Mesozoic deformation, the next major deformation that can be documented is late Cenozoic (beginning ~12 Ma) with the formation of diverse structures. South of the Sichuan basin folds and thrust faults form a multiply deformed area that involves Precambrian basement rocks and Phanerozoic sedimentary rocks with a modified dome and basin interference pattern. These folds and thrust fault project northward into the southern Sichuan basin where most of them end within the basin, but the Longchuan anticline on the east and several folds on the west continue north; the Longchuan anticline curves west into the middle of the Longmen Shan and the western structures form the eastern margin of the NE-trending Longmen Shan. At this latitude the structures involve only Mesozoic rocks above a decollement that underlies the Chengdu plain, but ramps down to the west beneath Precambrian cored structures that form the core of the Longmen Shan. These basement involved structures have a modified fault propagation fold geometry. Northward, the margin of the Tibetan plateau curves to the west along the N-S trending Min Shan formed by active east-vergent steep thrust faults. These structures may be localized by crustal anisotropy between the Xue Shan plateau and Song Pan Ganze flysch basin. A

  6. Holocene hillslope processes and deposits in two U-shaped mountain valleys in western Norway

    NASA Astrophysics Data System (ADS)

    Laute, K.; Beylich, A. A.

    2012-04-01

    This doctoral research project is integrated in the Norwegian Research Council (NFR) funded SedyMONT-Norway Project within the ESF EUROCORES TOPO-EUROPE SedyMONT (Timescales of sediment dynamics, climate and topographic change in mountain landscapes) Programme. Research is carried out within two steep, U-shaped and glacier-connected tributary valleys (Erdalen and Bødalen) on the western side of the Jostedalsbreen ice cap in western Norway. Contemporary denudative processes in both valley systems include rock and boulder falls, avalanches, slush flows, debris flows, creep processes, wash- and chemical denudation and fluvial transport of solutes, suspended sediments and bedload. The main aims of this research project which are approached within a Holocene to contemporary timescale are: (i) to investigate the spatio-temporal variability of Holocene hillslope development, (ii) to analyse more specificly the morphometric influences and geomorphic consequences of the Little Ice Age (LIA) glacier advance on selected hillslope systems within defined headwater areas in both valleys, (iii) to study morphometric and meteorological controls of contemporary denudative slope processes as well as (iv) to quantify the rates of sediment delivery from headwater areas and its changes over time. A process-based approach is applied using a variety of different methods and techniques. Focus is on different temporal (Holocene to contemporary) and spatial (selected hillslope systems, headwater areas and entire valley system) scales. The applied methods include orthophoto- and topographical map interpretation, GIS and DEM computing, geomorphological fieldmapping and hillslope profile surveying complemented by relative dating techniques (lichenometry and dendrochronology), geophysical investigations and terrestrial laser scanning (LIDAR). For monitoring contemporary rates of slope processes a designed monitoring programme (running since 2009) with a wide spectrum of instrumentation; e

  7. Electrical and geochemical properties of tufa deposits as related to mineral composition in the South Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Gomaa, Mohamed M.; Abou El-Anwar, Esmat A.

    2015-06-01

    The geochemical, petrographical, and electrical properties of rocks are essential to the investigation of the properties of minerals. In this paper we will try to present a study of the A. C. electrical properties of carbonate rock samples and their relation to petrographical and geochemical properties. Samples were collected from four formations from the Bir Dungul area, in the South Western Desert, Egypt. The electrical properties of the samples were measured using a non-polarizing electrode, at room temperature (~28 °C), and at a relative atmospheric humidity of (~45%), in the frequency range from 42 Hz to 5 MHz. The changes in the electrical properties were argued to the change in mineral composition. Generally, the electrical properties of rocks are changed due to many factors e.g., grain size, mineral composition, grain shape and inter-granular relations between grains. The dielectric constant of samples decreases with frequency, and increases with conductor concentration. Also, the conductivity increases with an increase of continuous conductor paths between electrodes. The petrographical and geochemical studies reveal that the deposition of the tufa deposits occurred in shallow lakes accompanied by a high water table, an alkaline spring recharge and significant vegetation cover. Diagenetically, tufa deposits were subjected to early and late diagenesis. Petrography and geochemistry studies indicated that the area of tufa deposits was deposited under the control of bacterial activity. Geochemically, the Sr content indicates that the tufa deposits formed from dissolved bicarbonate under the control of microbes and bacterial activity.

  8. Paleotopographic control of landslides in lacustrine deposits (Trièves plateau, French western Alps)

    NASA Astrophysics Data System (ADS)

    Bièvre, Grégory; Kniess, Ulrich; Jongmans, Denis; Pathier, Erwan; Schwartz, Stéphane; van Westen, Cees J.; Villemin, Thierry; Zumbo, Vilma

    2011-01-01

    Paleotopography in Quaternary sedimentary environments can be an important factor that controls landslide movement. This study investigates the relation between paleotopography and landslide activity in two adjacent landslides in glaciolacustrine sediments located in the Trièves area (French western Alps). Although both are in slopes underlain by the same lacustrine deposits, the Avignonet and Harmalière landslides exhibit major differences in morphology and displacement rates. Through a combination of geological mapping, airborne light detection and ranging (LiDAR) data, aerial photographs, global positioning system (GPS), and seismic noise measurements, a three-dimensional impression was made of both landslides. The analysis reveals that the difference in kinematics between the two mass movements can be traced back to at least 50 years ago. The results show that the Harmalière slide, which failed catastrophically in 1981, is still much more active than the Avignonet landslide. The fear was that the Avignonet landslide might develop in a similar catastrophic manner, threatening a number of houses constructed on the landslide. A geophysical survey based on ambient noise measurements allowed us to map the base of the lacustrine clays, and the results indicate the presence of a N-S ridge of hard sediments (Jurassic bedrock and/or compact alluvial layers) on the eastern side of the Avignonet landslide. This ridge disappears when approaching the Harmalière landslide and makes a place to what can be interpreted as a NW-SE oriented paleovalley of the river Drac. We proposed that the ridge acts as a buttress that could mechanically prevent the Avignonet landslide from evolving as fast as the Harmalière. Furthermore, the NW-SE paleovalley located under the Harmalière landslide corresponds to the motion direction of the slide. Therefore, the different behaviour of the two landslides is partly controlled by the paleotopographic setting of Lake Trièves during the last

  9. Mineralogical and geochemical characteristics of the Archaean LCT pegmatite deposit Cattlin Creek, Ravensthorpe, Western Australia

    NASA Astrophysics Data System (ADS)

    Bauer, Matthias; Dittrich, Thomas; Seifert, Thomas; Schulz, Bernhard

    2014-05-01

    The LCT (lithium-cesium-tantalum) pegmatite Cattlin Creek is located about 550 km ESE of Perth, Western Australia. The complex-type, rare-element pegmatite is hosted in metamorphic rocks of the Archaean Ravensthorpe greenstone belt, which constitutes of the southern edge of the Southern Cross Terranes of the Yilgarn Craton. The deposit is currently mined for both lithium and tantalum by Galaxy Resources Limited since 2010. The pegmatitic melt intruded in a weak structural zone of crossing thrust faults and formed several pegmatite sills, of which the surface nearest mineralized pegmatite body is up to 21 m thick. The Cattlin Creek pegmatite is characterized by an extreme fractionation that resulted in the enrichment of rare elements like Li, Cs, Rb, Sn and Ta, as well as the formation of a vertical zonation expressed by distinct mineral assemblages. The border zone comprises a fine-grained mineral assemblage consisting of albite, quartz, muscovite that merges into a medium-grained wall zone and pegmatitic-textured intermediate zones. Those zones are manifested by the occurrence of megacrystic spodumene crystals with grain sizes ranging from a couple of centimeters up to several metres. The core zone represents the most fractionated part of the pegmatite and consists of lepidolite, cleavelandite, and quartz. It also exhibits the highest concentrations of Cs (0.5 wt.%), Li (0.4 wt.%), Rb (3 wt.%), Ta (0.3 wt.%) and F (4 wt.%). This zone was probably formed in the very last crystallization stage of the pegmatite and its minerals replaced earlier crystallized mineral assemblages. Moreover, the core zone hosts subordinate extremely Cs-enriched (up to 13 wt.% Cs2O) mineral species of beryl. The chemical composition of this beryl resamples that of the extreme rare beryl-variety pezzotaite. Other observed subordinate, minor and accessory minerals comprise tourmaline, garnet, cassiterite, apatite, (mangano-) columbite, tantalite, microlite (Bi-bearing), gahnite, fluorite

  10. Nahcolite and halite deposition through time during the saline mineral phase of Eocene Lake Uinta, Piceance Basin, western Colorado

    USGS Publications Warehouse

    Johnson, Ronald C.; Brownfield, Michael E.

    2013-01-01

    Halite and the sodium bicarbonate mineral nahcolite were deposited during the saline phase of Eocene Lake Uinta in the Piceance Basin, western Colorado. Variations in the area of saline mineral deposition through time were interpreted from studies of core and outcrop. Saline minerals were extensively leached by groundwater, so the original extent of saline deposition was estimated from the distribution of empty vugs and collapse breccias. Vugs and breccias strongly influence groundwater movement, so determining where leaching has occurred is an important consideration for in-situ oil shale extraction methods currently being developed. Lake Uinta formed when two smaller fresh water lakes, one in the Uinta Basin of eastern Utah and the other in the Piceance Basin of western Colorado, expanded and coalesced across the Douglas Creek arch, an area of comparatively low subsidence rates. Salinity increased shortly after this expansion, but saline mineral deposition did not begin until later, after a period of prolonged infilling created broad lake-margin shelves and a comparatively small deep central lake area. These shelves probably played a critical role in brine evolution. A progression from disseminated nahcolite and nahcolite aggregates to bedded nahcolite and ultimately to bedded nahcolite and halite was deposited in this deep lake area during the early stages of saline deposition along with rich oil shale that commonly shows signs of slumping and lateral transport. The area of saline mineral and rich oil shale deposition subsequently expanded, in part due to infilling of the compact deep area, and in part because of an increase in water flow into Lake Uinta, possibly due to outflow from Lake Gosiute to the north. Finally, as Lake Uinta in the Piceance Basin was progressively filled from north to south by volcano-clastic sediment, the saline depocenter was pushed progressively southward, eventually covering much of the areas that had previously been marginal shelves

  11. Mass-movement deposits in the lacustrine Eocene Green River Formation, Piceance Basin, western Colorado

    USGS Publications Warehouse

    Johnson, Ronald C.; Birdwell, Justin E.; Brownfield, Michael E.; Mercier, Tracey J.

    2015-01-01

    The Eocene Green River Formation was deposited in two large Eocene saline lakes, Lake Uinta in the Uinta and Piceance Basins and Lake Gosiute in the Greater Green River Basin. Here we will discuss mass-movement deposits in just the Piceance Basin part of Lake Uinta.

  12. Magmatism and Epithermal Gold-Silver Deposits of the Southern Ancestral Cascade Arc, Western Nevada and Eastern California

    USGS Publications Warehouse

    John, David A.; du Bray, Edward A.; Henry, Christopher D., (compiler); Vikre, Peter

    2015-01-01

    Many epithermal gold-silver deposits are temporally and spatially associated with late Oligocene to Pliocene magmatism of the southern ancestral Cascade arc in western Nevada and eastern California. These deposits, which include both quartz-adularia (low- and intermediate-sulfidation; Comstock Lode, Tonopah, Bodie) and quartz-alunite (high-sulfidation; Goldfield, Paradise Peak) types, were major producers of gold and silver. Ancestral Cascade arc magmatism preceded that of the modern High Cascades arc and reflects subduction of the Farallon plate beneath North America. Ancestral arc magmatism began about 45 Ma, continued until about 3 Ma, and extended from near the Canada-United States border in Washington southward to about 250 km southeast of Reno, Nevada. The ancestral arc was split into northern and southern segments across an inferred tear in the subducting slab between Mount Shasta and Lassen Peak in northern California. The southern segment extends between 42°N in northern California and 37°N in western Nevada and was active from about 30 to 3 Ma. It is bounded on the east by the northeast edge of the Walker Lane. Ancestral arc volcanism represents an abrupt change in composition and style of magmatism relative to that in central Nevada. Large volume, caldera-forming, silicic ignimbrites associated with the 37 to 19 Ma ignimbrite flareup are dominant in central Nevada, whereas volcanic centers of the ancestral arc in western Nevada consist of andesitic stratovolcanoes and dacitic to rhyolitic lava domes that mostly formed between 25 and 4 Ma. Both ancestral arc and ignimbrite flareup magmatism resulted from rollback of the shallowly dipping slab that began about 45 Ma in northeast Nevada and migrated south-southwest with time. Most southern segment ancestral arc rocks have oxidized, high potassium, calc-alkaline compositions with silica contents ranging continuously from about 55 to 77 wt%. Most lavas are porphyritic and contain coarse plagioclase

  13. Rujevac Sb-Pb-Zn-As polymetallic deposit, Boranja orefield, Western Serbia: native arsenic and arsenic mineralization

    NASA Astrophysics Data System (ADS)

    Radosavljević, Slobodan A.; Stojanović, Jovica N.; Radosavljević-Mihajlović, Ana S.; Vuković, Nikola S.

    2014-02-01

    Rujevac is a low-temperature hydrothermal polymetallic Sb-Pb-Zn-As vein-type ore deposit, hosted within a volcanogenic-sedimentary zone situated in the Rujevac-Crvene Stene-Brezovica Diabase-Chert Formation (DCF) of the Podrinje Metallogenic District (PMD), Serbia. It is located several kilometers SE from the Boranja contact aureole, which is an integral part of the PMD in Western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral assemblages are characterized by specific features. The mineral association of this deposit consists of sulfides, Pb-Sb(As) sulfosalts, native metals, oxides, hydroxides and gangue minerals. Chemical composition of the ore is very complex, where contents of valuable metals range as follows: Sb (0.17-24.31 wt.%), Zn (0.21-6.29 wt.%), Pb (0.15-6.33 wt.%), As (0.06-1.28 wt.%), Cd (25-747 ppm), Ag (7-408 ppm), Hg (13-473 ppm), and Tl (<1-29 ppm). Electron Probe Microanalyses (EPMA) of native arsenic from both the Rujevac and Stragari deposits showed contents of As up to 98.8 and 97.1 wt.%, with impurity contents of Sb up to 1.3 and 6.6 wt.%, and Tl up to 2 and 1.3 wt.%, respectively. Rhombohedral unit-cell parameters for native arsenic from Rujevac and Stragari deposits amount to: a = 3.760(2), c = 10.555(3) Å, V = 129.23(7) Å3 and a = 3.763(1), c = 10.560(5) Å, V = 129.48(8) Å3, respectively. Mineral assemblages, deposition order and genesis of the Rujevac polymetallic deposit were also discussed in detail. Native arsenic mineralization here has been additionally compared with similar well-known global deposits.

  14. Rujevac Sb-Pb-Zn-As polymetallic deposit, Boranja orefield, Western Serbia: native arsenic and arsenic mineralization

    NASA Astrophysics Data System (ADS)

    Radosavljević, Slobodan A.; Stojanović, Jovica N.; Radosavljević-Mihajlović, Ana S.; Vuković, Nikola S.

    2013-05-01

    Rujevac is a low-temperature hydrothermal polymetallic Sb-Pb-Zn-As vein-type ore deposit, hosted within a volcanogenic-sedimentary zone situated in the Rujevac-Crvene Stene-Brezovica Diabase-Chert Formation (DCF) of the Podrinje Metallogenic District (PMD), Serbia. It is located several kilometers SE from the Boranja contact aureole, which is an integral part of the PMD in Western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral assemblages are characterized by specific features. The mineral association of this deposit consists of sulfides, Pb-Sb(As) sulfosalts, native metals, oxides, hydroxides and gangue minerals. Chemical composition of the ore is very complex, where contents of valuable metals range as follows: Sb (0.17-24.31 wt.%), Zn (0.21-6.29 wt.%), Pb (0.15-6.33 wt.%), As (0.06-1.28 wt.%), Cd (25-747 ppm), Ag (7-408 ppm), Hg (13-473 ppm), and Tl (<1-29 ppm). Electron Probe Microanalyses (EPMA) of native arsenic from both the Rujevac and Stragari deposits showed contents of As up to 98.8 and 97.1 wt.%, with impurity contents of Sb up to 1.3 and 6.6 wt.%, and Tl up to 2 and 1.3 wt.%, respectively. Rhombohedral unit-cell parameters for native arsenic from Rujevac and Stragari deposits amount to: a = 3.760(2), c = 10.555(3) Å, V = 129.23(7) Å3 and a = 3.763(1), c = 10.560(5) Å, V = 129.48(8) Å3, respectively. Mineral assemblages, deposition order and genesis of the Rujevac polymetallic deposit were also discussed in detail. Native arsenic mineralization here has been additionally compared with similar well-known global deposits.

  15. High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

    NASA Astrophysics Data System (ADS)

    Sickman, J. O.

    2011-12-01

    Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

  16. A late quaternary record of eolian silt deposition in a maar lake, St. Michael Island, western Alaska

    USGS Publications Warehouse

    Muhs, D.R.; Ager, T.A.; Been, J.; Bradbury, J.P.; Dean, W.E.

    2003-01-01

    Recent stratigraphic studies in central Alaska have yielded the unexpected finding that there is little evidence for full-glacial (late Wisconsin) loess deposition. Because the loess record of western Alaska is poorly exposed and not well known, we analyzed a core from Zagoskin Lake, a maar lake on St. Michael Island, to determine if a full-glacial eolian record could be found in that region. Particle size and geochemical data indicate that the mineral fraction of the lake sediments is not derived from the local basalt and is probably eolian. Silt deposition took place from at least the latter part of the mid-Wisconsin interstadial period through the Holocene, based on radiocarbon dating. Based on the locations of likely loess sources, eolian silt in western Alaska was probably deflated by northeasterly winds from glaciofluvial sediments. If last-glacial winds that deposited loess were indeed from the northeast, this reconstruction is in conflict with a model-derived reconstruction of paleowinds in Alaska. Mass accumulation rates in Zagoskin Lake were higher during the Pleistocene than during the Holocene. In addition, more eolian sediment is recorded in the lake sediments than as loess on the adjacent landscape. The thinner loess record on land may be due to the sparse, herb tundra vegetation that dominated the landscape in full-glacial time. Herb tundra would have been an inefficient loess trap compared to forest or even shrub tundra due to its low roughness height. The lack of abundant, full-glacial, eolian silt deposition in the loess stratigraphic record of central Alaska may be due, therefore, to a mimimal ability of the landscape to trap loess, rather than a lack of available eolian sediment. ?? 2003 University of Washington. Published by Elsevier Inc. All rights reserved.

  17. Tectonic control of Cretaceous gravity deposits and submarine Valleys in the subalpine basin, French western Alps

    SciTech Connect

    Philippe, J.; Beaudoin, B.; Fries, G.; Parize, O.

    1988-08-01

    The Late Jurassic-Early Cretaceous series of the French subalpine basin is characterized by alternating limestones and marls with numerous, thick gravity-flow deposits (carbonate debris flows and slumps, siliciclastic grain flows, turbidites). These gravity deposits originate from platforms and slopes and come through the basin via several parallel canyons and submarine valleys. Some carbonate (Berriasian) and siliciclastic (Aptian) deep-sea fans are built at the canyon mouth during intense activity of the canyons and reworking of the sediments. The tectonic control of the gravity deposits is demonstrated by the position and filling of the submarine valleys all along the Cretaceous. The submarine valleys correspond systematically to the lower part of extensional tilted blocks; the gravity deposits come along the main syn-sedimentary normal faults delimiting these tilted blocks. The gravity deposits go from one tilted block to another through some synsedimentary passes which are induced by slight folding, perhaps related to an early diapirism at some nodes of extensional faults. The canyon-like valleys are due to very strong erosion when a submarine valley cuts of the higher part of a tilted block. The gravity deposits are stacked atop each other and progressively fill the valleys. Thus the cutting and filling of the submarine valleys and canyons on occasions during the Early Cretaceous are explained by a permanent synsedimentary activity. These Jurassic and Cretaceous extensional structures are later reactivated by inversion during Tertiary compressional movements.

  18. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. National Park fish: concentrations and consumption guidelines.

    PubMed

    Ackerman, Luke K; Schwindt, Adam R; Simonich, Staci L Massey; Koch, Dan C; Blett, Tamara F; Schreck, Carl B; Kent, Michael L; Landers, Dixon H

    2008-04-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit--18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1% relative standard deviation (RSD)), and accurate (7% deviation from standard reference material (SRM)) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs, and chlordanes in western U.S. fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western U.S. fish were 1-6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, lake average contaminant concentrations in fish exceeded subsistence fishing cancer thresholds in 8 of 14 lakes and wildlife contaminant health thresholds for piscivorous birds in 1 of 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. PMID:18504962

  19. Atmospherically Deposited PBDEs, Pesticides, PCBs, and PAHs in Western US National Park Fish: Concentrations and Consumption Guidelines

    PubMed Central

    Ackerman, Luke K.; Schwindt, Adam R.; Simonich, Staci L.; Koch, Dan C.; Blett, Tamara F.; Schreck, Carl B.; Kent, Michael L.; Landers, Dixon H.

    2014-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western US National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit −18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1 %RSD), and accurate (7 % deviation from SRM) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs and chlordanes in western US fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western US fish were 1–6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, contaminant concentrations exceeded subsistence fishing cancer screening values in 8 of 14 lakes. Average contaminant concentrations in fish exceeded wildlife contaminant health thresholds for piscivorous mammals in 5 lakes, and piscivorous birds in all 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. PMID:18504962

  20. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. National Park fish: Concentrations and consumption guidelines

    USGS Publications Warehouse

    Ackerman, L.K.; Schwindt, A.R.; Simonich, S.L.M.; Koch, D.C.; Blett, T.F.; Schreck, C.B.; Kent, M.L.; Landers, D.H.

    2008-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and wildlife contaminant health thresholds. A sensitive (median detection limit, -18 pg/g wet weight), efficient (61% recovery at 8 ng/g), reproducible (4.1% relative standard deviation (RSD)), and accurate (7% deviation from standard reference material (SRM)) analytical method was developed and validated for these analyses. Concentrations of PCBs, hexachlorobenzene, hexachlorocyclohexanes, DDTs, and chlordanes in western U.S. fish were comparable to or lower than mountain fish recently collected from Europe, Canada, and Asia. Dieldrin and PBDE concentrations were higher than recent measurements in mountain fish and Pacific Ocean salmon. Concentrations of most contaminants in western U.S. fish were 1-6 orders of magnitude below calculated recreational fishing contaminant health thresholds. However, lake average contaminant concentrations in fish exceeded subsistence fishing cancer thresholds in 8 of 14 lakes and wildlife contaminant health thresholds for piscivorous birds in 1of 14 lakes. These results indicate that atmospherically deposited organic contaminants can accumulate in high elevation fish, reaching concentrations relevant to human and wildlife health. ?? 2008 American Chemical Society.

  1. [Emergy evaluation and dynamic measurement analysis of agro-ecosystems in Sichuan Province of Southwest China].

    PubMed

    Zhang, Ying-Cong; Du, Shou-Hu

    2012-03-01

    Agro-ecosystem is the most basic system for human beings survival, while the analysis of the structure and function of the system is the key to solve the problems of agro-ecological environment. In this paper, emergy theory and related economic measurement methods including data envelopment analysis, cointegration test, and error correction model were applied to quantitatively analyze the operation dynamics, environmental loading, operation efficiency, and input-output relation of the agro-ecosystems in Sichuan Province and its 21 cities in 1997-2009. In the study period, Sichuan Province was in the transition period from traditional agriculture to modern agriculture. The agricultural mechanization level of the Province improved constantly, resources utilization efficiency enhanced continually, overall structural dominant degree was better, but the over-reliance on economic emergy input caused the sustainability of the system weakened gradually. The development status of the agro-ecosystems in the Province varied among regions. Chengdu Plain and Western Sichuan Highland were either in overexploited or in underutilized, while the hilly areas were full of vitality and development potential, tended to be the important areas for the future development of Sichuan agriculture. Generally, the operation efficiency of the agro-ecosystems in the Province was relatively low, with the situation differed in different regions due to the lower technical efficiency or improper scale. There was a long-term equilibrium between the economic emergy indices and output emergy, but the short-term emergy input didn't reach the ideal output. PMID:22720632

  2. Use of passive samplers and surrogate surfaces to investigate sources of mercury deposited to the western United States

    NASA Astrophysics Data System (ADS)

    Wright, G.; Gustin, M. S.; Weiss-Penzias, P. S.

    2012-12-01

    The Western Airborne Contaminants Assessment Project (WACAP) showed that fish in eight National Parks of the western U.S. had mercury(Hg) concentrations that exceeded the threshold for fish eating wildlife (www.nature.nps.gov/air/Studies/air_toxics/wacap.cfm). These observations led to the development of this study focused on investigating air gaseous oxidized mercury (GOM) concentrations and potential dry deposition using developed passive samplers and surrogate surfaces. The primary question was whether local, regional or global sources are responsible for the mercury measured in fish in these Western parks. To investigate this, passive samplers and surrogate surface samplers were deployed from the coast of California to the eastern edge of Nevada. Sampling sites were located from west to east at Point Reyes National Seashore, CA; Elkhorn Slough, CA, Lick Observatory, CA; Chews Ridge, CA; Chalk Mountain, CA; Yosemite National Park, CA; Sequoia & Kings Canyon National Park, CA; and Great Basin National Park, NV. Ancillary data (meteorology and ozone concentrations) collected by the parks will be applied to better understand potential sources. Air mercury concentrations were also measured at select locations using a Tekran® 2537a/1130mercury air measurement system for 4-6 weeks. Air GOM concentrations and potential deposition were measured simultaneously as a function of elevation at Yosemite and Great Basin National Park, using the passive samplers and surrogate surfaces during sampling intensives, allowing us to better understand potential sources of mercury to park ecosystems. Data collection began in August of 2010 and was completed in June 2012. Analyses of the data thus far has shown the lowest relative concentrations and potential GOM deposition were observed at the low elevation coastal sites, Elkhorn Slough and Point Reyes National Seashore. Highest values of potential deposition were recorded at Lick Observatory, a high elevation coastal site, while

  3. Map showing occurrences of spring-deposited travertine in the conterminous Western United States

    USGS Publications Warehouse

    Feth, J.H.; Barnes, Ivan

    1979-01-01

    Extinct travertine terraces occur hundreds of meters above present levels of spring activity and have potentials for interpretation of ancient hydrologic systems, rates of downcutting, or rates of tectonic uplift that remain virtually unexploited. The abundance and size of extinct travertine deposits suggest that in many places, such as pinnacles at the southwest end of the Searles Lake basin, California, spring activity was once more widespread and copious than it is now. Travertine of Eocene age has been reported, and a scattering of later Tertiary occurrences is known. But where age has been inferred, the inferred ages are predominantly Pleistocene or younger. So travertine seems to be a geologically transient phenomenon, subject either to removal by erosion or to burial and disappearance. Many travertine deposits are known to be on or close to faults. Their occurrence in otherwise structurally featureless alluvial valleys may, therefore, suggest the possibility of a hidden fault. From the Front Range to the Pacific, more than 300 travertime deposits have been identified. The map shows that the deposits are widely dispersed. However, there are apparent groupings on the Wasatch Fault and associated tectonic areas trending northward in Utah and southern Idaho, and also near the great fault zone that marks the eastern boundary of the Sierra Nevada, California. (Lantz-PTT)

  4. The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran

    USGS Publications Warehouse

    Sholeh, Ali; Rastad, Ebrahim; Huston, David L.; Gemmell, J. Bruce; Taylor, Ryan D.

    2016-01-01

    The Chahnaly Au deposit formed during the early stages of magmatism. LA-ICP-MS zircon U-Pb geochronology of host andesite and 40Ar/39Ar dating of two samples of gold-associated adularia show that the ore-stage adularia (19.83 ± 0.10 and 19.2 ± 0.5 Ma) is younger, by as much as 1.5 million years, than the volcanic host rock (20.32 ± 0.4 Ma). Therefore, either hydrothermal activity continued well after volcanism or a second magmatic event rejuvenated hydrothermal activity. This second magmatic event may be related to eruption of porphyritic andesite at ~20.32 ± 0.40 Ma, which is within error of ~19.83 ± 0.10 Ma adularia. The new LA-ICP-MS zircon U-Pb host rock and vein adularia 40Ar/39Ar ages suggest that early Miocene magmatism and mineralization in the Bazman area is of a similar age to that of the Saindak porphyry and Tanjeel porphyry center of the giant Reko Diq deposit. This confirms the existence of early Miocene arc magmatism and mineralization along the Iranian part of the Makran volcanic arc. Ore, alteration mineralogy, and alteration patterns indicate that the Chahnaly deposit is a typical low-sulfidation epithermal Au deposit, located in a poorly explored part of the Makran volcanic arc in Iran.                   

  5. Precipitation source inferred from stable isotopic composition of Pleistocene groundwater and carbonate deposits in the western desert of Egypt.

    SciTech Connect

    Sultan, M.; Sturchio, N.; Hassan, F. A.; Abdel, M.; Hamdan, R.; Mahmood, A. M.; Alfy, Z. E.; Stein, T.; Environmental Research; Univ. Coll. London; Cairo Univ.; Ain Shams Univ.; Egyptian Geological survey and Mining Authority; Washington Univ.

    1997-01-01

    An Atlantic source of precipitation can be inferred from stable isotopic data (H and O) for fossil groundwaters and uranium-series-dated carbonate spring deposits from oases in the Western Desert of Egypt. In the context of available stable isotopic data for fossil groundwaters throughout North Africa, the observed isotopic depletions ({delta}D -72 to -81{per_thousand}; {delta}{sup 18}O -10.6 to -11.5{per_thousand}) of fossil ({ge}32,000 yr B.P.) groundwaters from the Nubian aquifer are best explained by progressive condensation of water vapor from paleowesterly wet oceanic air masses that traveled across North Africa and operated at least as far back as 450,000 yr before the present. The values of {delta}{sup 18}O (17.1 to 25.9{per_thousand}) for 45,000- to >450,000-yr-old tufas and vein-filling calcite deposits from the Kharga and Farafra Oases are consistent with deposition from groundwaters having oxygen isotopic compositions similar to those of fossil groundwaters sampled recently at these locations.

  6. Combined effect of tectonism, eustasy, and sediment supply on the depositional-sequence history of the western offshore, South Africa

    SciTech Connect

    Jungslager, E.H.A. )

    1991-03-01

    Interpreted seismic profiles and maps of depositional systems tracts highlight variations in basin-fill architecture and their inferred causes along western offshore South Africa. Sequence-stratigraphic concepts developed by Exxon were used to interpret 10,000 km of seismic data and logs from 31 exploration boreholes within an area of 90,000 km{sup 2}. Lower frequency second-order supercycles (5-10 Ma) are attributed to changes in the rate of subsidence and are expressed either by predominantly progradational or aggradational depositional supersequence. In addition to these long-duration, basin-wide stratigraphic packages, component depositional sequences that formed in response to third order (1-5 Ma) and higher frequency cycles vary with structural setting within the depobasin, namely depocenter, basin flanks, shelf-edge, and slope systems. High-order sequences are attributed to eustatically driven, high-frequency, base-level changes and/or localized tectonic events (i.e. slope failure, gravity faulting). Variations in the areal distribution of lowstand and shelf-margin systems tracts document lateral shifting sediment supplies and the presence of entrenched feeder-canyons linked to incised valley systems on the shelf. Many canyons, however, terminate updip and may be related to slope failure and headward erosion. The tentative correlation of regionally developed unconformities of the west coast based on microfaunal dating of a limited number of marine condensed sections points to a remarkable correspondence with the Exxon global sea-level chart.

  7. Control on the erosional and depositional dynamics inferred from grain size variation along the Pisco river, Western Peru.

    NASA Astrophysics Data System (ADS)

    Camille, Litty; Robert, Duller; Fritz, Schlunegger

    2015-04-01

    The Pisco Valley situated on the western side of the Andes represents an ideal laboratory for exploring potential controls on the accumulation and subsequent erosion of sediment because it hosts several well-preserved cut-and-fill terrace sequences. In this study we infer that a climatic change in combination with eustatic sea level drop have been the main drivers of erosion of the valley flanks and subsequent sedimentation of the Quaternary terrace deposits. We mostly focused on the sediments of the well preserved 40 ka-old terrace level (Minchin pluvial period) and compare them with the modern bed material to explore relationships between longitudinal and temporal variations of grain size downstream fining, water budgets and sediment transport dynamics recorded by the modern and the terrace deposits. To this extent, grain size data were collected from digital images taken at five different sites along the channel. We measured the b-axis of the particles on digital images, which yielded in a total of ca. 2500 grain size measurements per site for the modern material and ca. 4000 per site for the terrace deposits. The results reveal a higher downstream fining rate for the modern material than for the terrace deposits for the D50 and D84 but the inverse for the D96. For the modern sediments, the fining rate is 0.7 mm/km for the D50 while the equivalent percentile of the terrace deposits has a lower fining rate of 0.3 mm/km. The modern deposits are better sorted and have finer grains than the ancient sediments. The results of hydrological calculations suggest that the water discharge required to transport the D50 of the Pisco River during modern and Minchin times and to evacuate the supplied material has been nearly identical whereas the water discharge required to transport supplied material is higher during the Minchin time than today if the D96 is taken as threshold value. We propose a scenario where eustatic sea level drop initiated the beginning of the

  8. Morphology and geology of an interior layered deposit in the western Tithonium Chasma, Mars

    NASA Astrophysics Data System (ADS)

    Baioni, Davide

    2013-12-01

    This paper describes a morphologic and morphometric survey of a 3.1 km-high, domeshaped upland in western Tithonium Chasma (TC) which coincides with areas containing abundant surface signatures of the sulphate mineral kiersite, as identified by the OMEGA image spectrometer. The morphologic features of the dome were investigated through an integrated analysis of the available Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE), Mars Orbiter Camera, and Context Camera data, while the morphometric characteristics of the structure were measured using a topographic map (25-m contour interval) built from high-resolution stereo camera (HRSC) and Mars Orbiter Laser Altimeter (MOLA) data.

  9. Black Carbon Deposition on Glaciers and in the Seasonal Snowpack in Western Washington's Mountainous Regions

    NASA Astrophysics Data System (ADS)

    Delaney, I.; Kaspari, S.; Larrabee, M.

    2012-12-01

    Black carbon deposition on snow and ice darkens the surface of glaciers and snowpack, reducing albedo. Radiation absorbed by black carbon in snow can accelerate snowmelt and change the timing of runoff. This is particularly important in Washington State, as glaciers and seasonal snowpack have shrunk considerably in recent years and are integral to the region's water resources. However, little data exists regarding the concentration of black carbon in Washington snow, which is necessary to determine if enough black carbon is present to substantially accelerate snowmelt. From the winter through the summer of 2012, we collected snow samples from the snow surface, snow pits and snow cores (< 5 m depth, in many cases capturing the entire annual snowpack). Study sites include the Nisqually and Emmons glaciers on Mt. Rainier, Blewett Pass in the central Cascades, N. Klawatti, Noisy and Sandalee glaciers in the North Cascades and Blue Glacier on Mt. Olympus. Samples were analyzed for black carbon using a Single Particle Soot Photometer (SP2), and select samples were also analyzed for black carbon using a Sunset Lab OC-EC Aerosol Analyzer to compare with the SP2 method. We use the resultant data set to examine how snow accumulation, dry deposition, and proximity to emission sources (such as the Puget Sound metropolitan area) affect black carbon concentration in snow and ice. The results of this research provide insight in to 1) regional scale variation in black carbon deposition, 2) temporal trends in black carbon deposition, and 3) the persistence of black carbon in the snowpack throughout the season.

  10. Effects of African dust deposition on phytoplankton in the western tropical Atlantic Ocean off Barbados

    NASA Astrophysics Data System (ADS)

    Chien, Chia-Te; Mackey, Katherine R. M.; Dutkiewicz, Stephanie; Mahowald, Natalie M.; Prospero, Joseph M.; Paytan, Adina

    2016-05-01

    Bioassay incubation experiments conducted with nutrients and local atmospheric aerosol amendments indicate that phosphorus (P) availability limited phytoplankton growth in the low-nutrient low-chlorophyll (LNLC) ocean off Barbados. Atmospheric deposition provides a relatively large influx of new nutrients and trace metals to the surface ocean in this region in comparison to other nutrient sources. However, the impact on native phytoplankton is muted due to the high ratio of nitrogen (N) to P (NO3:SRP > 40) and the low P solubility of these aerosols. Atmospheric deposition induces P limitation in this LNLC region by adding more N and iron (Fe) relative to P. This favors the growth of Prochlorococcus, a genus characterized by low P requirements and highly efficient P acquisition mechanisms. A global three-dimensional marine ecosystem model that includes species-specific phytoplankton elemental quotas/stoichiometry and the atmospheric deposition of N, P, and Fe supports this conclusion. Future increases in aerosol N loading may therefore influence phytoplankton community structure in other LNLC areas, thereby affecting the biological pump and associated carbon sequestration.

  11. Frozen subduction in the Yangtze block: insights from the deep seismic profiling and gravity anomaly in east Sichuan fold belt

    NASA Astrophysics Data System (ADS)

    Xiong, Xiaosong; Gao, Rui; Wang, Haiyan; Zhang, Jisheng; Guo, Lianghui

    2016-04-01

    The Sichuan basin is the main part of the middle-upper Yangtze block, which has been experienced a long-term tectonic evolution since Archean. The Yangtze block was regarded as a stable block until the collision with the Cathaysia block in late Neoproterozoic. A new deep seismic reflection profile conducted in the eastern Sichuan fold belt (ESFB) discovered a serials of south-dipping reflectors shown from lower crust to the mantle imply a frozen subduction zone within the Yangtze block. In order to prove the speculation, we also obtain the middle-lower crustal gravity anomalies by removing the gravity anomalies induced by the sedimentary rocks and the mantle beneath the Moho, which shows the mid-lower crustal structure of the Sichuan basin can be divided into eastern and western parts. Combined with the geochronology and Aeromagnetic anomalies, we speculated the Yangtze block was amalgamated by the West Sichuan and East Sichuan blocks separated by the Huayin-Chongqing line. The frozen subduction zone subsequently shifted to a shear zone accommodated the lower crustal shortening when the decollement at the base of the Nanhua system functioned in the upper plate.

  12. Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

    NASA Astrophysics Data System (ADS)

    Tripaldi, Alfonsina; Forman, Steven L.

    2016-05-01

    The Pampean Sand Sea, which occurs from the Argentinian Pampas to the eastern Andean piedmont, hosts presently stabilized dune fields spanning the late Quaternary. This study integrates previous results and presents new geomorphic, stratigraphic, sedimentological, and chronologic data for nineteen >2 m-thick eolian successions for the San Luis paleo-dune field, western Pampas, to better constrain the depositional history. Six eolian depositional phases are identified spanning the past 50 ka, interposed with paleosols and/or bounded by erosive surfaces. Age control was from 61 OSL ages of small aliquots of quartz grains from eolian stratigraphic units. The inferred timing of eolian phases are at ca. 70 ± 10 yr, 190 ± 20 yr, 12 to 1 ka, 22 to 17 ka, 29 to 24 ka, and 40 to 32 ka. A maximum span for periods of pedogenesis at ca. 12 to 17 ka, 22 to 24 ka, and 29 to 32 ka was provided by bounding OSL ages, which broadly overlap with high stands of pluvial lakes and glacier advances in the central Andes. We infer that the added precipitation may reflect expansion of the Southern Hemisphere monsoon, associated with Northern Hemisphere Heinrich events, leading to episodes of significantly wetter conditions (>350 mm MAP) to at least 35° S. Most of the Holocene (12 ka to 0.8 ka) was characterized by sand sheet deposit under drier than present conditions (100-450 mm MAP), associated with Monte-type vegetation (shrub steppe). The latest two eolian depositional phases, occurred at ca. 190 and 70 yr ago, during the historic period with European settlement and are related to anthropogenic landscape disturbance, though the youngest phase was concomitant with 1930s drought. Wet conditions dominated since ca. AD 1970 with new lakes and rivers forming across this eolian terrain; an incongruous environmental response in reference to drier conditions for most of the Holocene.

  13. Depositional patterns and hydrocarbon occurrence in middle to upper Miocene strata in part of the western Niger Delta Basin, Nigeria

    NASA Astrophysics Data System (ADS)

    Agyingi, C. M.; Agagu, O. K.; Fozao, K. F.; Njoh, O. A.; Ngalla, N.

    2013-04-01

    The relation of depositional patterns to hydrocarbon occurrence in middle to upper Miocene strata of part of the western Niger Delta Basin is postulated from the study of electrical logs, radiometric logs, lithologic logs, bottom hole temperatures, intervals of hydrocarbon occurrence and paleontological data. Alternating sands and shales of the Agbada Formation were deposited in the area (up to 720 m, middle Miocene and 510 m, upper Miocene) mainly as regressive off lap sequences in a paralic environment with depo-centers located in the south of the study area. Three deltaic facies can be recognized based on the relative amounts of shale and sand including, proximal delta front facies (>70% sand), distal delta front facies (30-70% sand) and prodelta facies (<30% sand). The upper Miocene is generally sandier than the middle Miocene as a result of south-westerly progradation of delta front facies from middle to upper Miocene. Geothermal gradients in the area range from 2.5 °C/100 m to 4.4 °C/100 m. Isothermal maps show that some middle to upper Miocene shales could have undergone catagenesis to become mature source rocks. Three depositional zones (A, B, C) corresponding to dominant depositional facies i.e., proximal delta, distal delta and prodelta respectively, have been delineated from sand percentage maps. There is a progression of these zones from A through B to C in a generally south-westerly direction (the direction of delta progradation). Data for hydrocarbon intervals reveal the predominance of hydrocarbons in Zone C due to high entrapment potentials and to a lesser extent in Zone B. Zone A is barren as a result of poor entrapment potentials. The juxtaposition of distal delta front sands and prodelta mud could have initiated growth faults which constitute the major types of traps in the basin.

  14. Mineralogy and sedimentology of the Miocene Göcenoluk borate deposit, Kırka district, western Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    García-Veigas, Javier; Helvacı, Cahit

    2013-05-01

    The Miocene boratiferous district of Kırka, in western Anatolia (Turkey), is the most important Na-borate (borax) resource in the world. Two separate deposits in the Kırka district are located near the villages of Sarıkaya and Göcenoluk (Eskişehir Province). Borax is intensively exploited in open-pit mines in the Sarıkaya deposit while only small quarries of colemanite are known in the Göcenoluk deposit. Recent exploratory drilling in the Göcenoluk area intersected a thick succession of dolostones, tuffs and three borate-bearing units (Lower, Intermediate and Upper Borate Units). In them, the most abundant borate mineral is ulexite (Ca-Na-borate) passing at depth to probertite. Borax (Na-borate) is only present in the Intermediate Borate Unit. Minor amounts of colemanite (Ca-borate) and hydroboracite (Ca-Mg-borate) occur at the base, and/or top, of each mineralized unit. Pyroclastic layers within the borate units show intense alteration by alkaline, boron-bearing waters and formation of diagenetic clay minerals (smectites), zeolites (analcime) and borosilicates (searlesite). The Göcenoluk succession is interpreted as a shallow, ephemeral, alkaline lake deposit in which carbonates formed as stromatolites and travertines. Borate precipitation in the Göcenoluk area took place interstitially within muddy and carbonate sediments in a lateral progression from marginal Ca-borates towards Na-Ca-borates and rarely to Na-borates in the center of the lake. Authigenic silicate mineral distribution shows parallel changes toward the center of the lake that reflect increasing pH gradient.

  15. Mineral-petrographic features of hydrocarbon reservoirs of the Tevlinsko-Russkinskoe oil deposit (Western Siberia)

    NASA Astrophysics Data System (ADS)

    Sitdikova, Elina; Izotov, Victor

    2010-05-01

    The Tevlinsko-Russkinskoe oil field is located in the central part of the West Siberian lowland. It concerns a group of multistory deposits and is one of the perspective deposits in the West Siberian oil and gas province. The young Sortym formation and the Jurassic sediments offer the best prospects. Layers are consisted of sand-clay deposits of Mesozoic-Cainozoic sedimentary cover and rocks of the pre-Jurassic basement. Core material of base drill holes of the Tevlinsko-Russkinskoe oil field was studied in order to obtain detailed lithological and mineralogical characteristics of rocks features. These drill holes found out main productive horizons. Sandstones of productive horizons of Jurassic petroliferous complex are of a homogeneous and monotonous structure. In the studied samples of core material massive structures prevail. Mineral composite of clastic component of sandstones is polymictic and it is represented by quartz, orthoclase, microcline, plagioclases, biotite, strongly changed dark-coloured minerals, fragments of effusive rocks and quartzite of different degrees of recrystallization. Cluster formation - grains accretion into separated quartzite-like parts - is typical for these rocks. Process of cluster formation is accompanied by change of sandstone structure. This results in reservoir quality alteration and extension of porosity and permeability properties. In the studied rocks-reservoirs of Jurassic oil complex processes of cluster formation were lasting during period of diagenesis and were followed by repartition of cement mass. We carried out electron microscopic research of reservoirs structure to analyze void space structure. Electron microscopic studies were spent on the scanning electron microscope of XL-30 system (Phillips company). The conducted research testifies that reservoirs can be considered a mesoporous-nanoporous medium. Its' studying is of a great importance for realization of questions of Tevlinsko-Russkinskoe oil field working out.

  16. A quantitative micropaleontologic method for shallow marine peleoclimatology: Application to Pliocene deposits of the western North Atlantic Ocean

    USGS Publications Warehouse

    Cronin, T. M.; Dowsett, H.J.

    1990-01-01

    A transfer function was developed to estimate summer and winter paleotemperatures for arctic to tropical regions of the western North Atlantic Ocean using fossil ostracode assemblages. Q-mode factor analysis was run on ostracode assemblages from 100 modern bottom sediment samples from continental shelves of North America, Greenland and the Caribbean using 59 ostracode taxa. Seven factors accounting for 80% of the variance define assemblages that correspond to frigid, subfrigid, cold temperate, mild temperate, warm temperate, subtropical and tropical climatic zones. Multiple regression of the factor matrix against observed February and August bottom temperatures yielded an astracode transfer function with an accuracy of about ??2??C. The transfer function was used to reconstruct middle Pliocene (3.5-3.0 Ma) shallow marine climates of the western North Atlantic during the marine transgression that deposited the Yorktown Formation (Virginia and North Carolina), the Duplin Formation (South and North Carolina) and the Pinecrest beds (Florida). Middle Pliocene paleowater temperatures in Virginia averaged 19??C in August and 13.5??C in February, about 5??C to 8??C warmer than at comparable depths off Virginia today. August and February water temperatures in North Carolina were 23??C and 13.4??C, in South Carolina about 23??C and 13.5??C and in southern Florida about 24.6??C and 15.4??C. Marine climates north of 35??N were warmer than today; south of 35??N, they were about the same or slightly cooler. Thermal gradients along the coast were generally not as steep as they are today. The North Atlantic transfer function can be applied to other shallow marine Pliocene and Pleistocene deposits of eastern North America. ?? 1990 Elsevier Science Publishers B.V.

  17. The Paddy's Flat Gold District (Murchison, Western Australia), insight on a rheologically and structurally control lode gold deposit

    NASA Astrophysics Data System (ADS)

    Thebaud, N.; Hollingsworth, D.; Gonzalez-Alvarez, I.

    2007-12-01

    In the North-West of the world class gold producer Yilgarn craton lies the Murchison Goldfield (Western Australia). Several rich deposits mined since the turn of the 19th century suggest that this late-Archaean terrane is highly prospective for gold exploration. Located in the northern part of the Murchison goldfield, the Paddy's Flat District recorded a production of ~2 Moz. The Paddy's Flat Gold District area is located on an N-S trending, steeply east dipping shear on the north western limb of an upright isoclinal fold known as the Polelle syncline. It is hosted in a strained and metamorphosed volcanic and minor sedimentary sequence. Mineralisation within the Paddy's Flat District is not limited to a particular rock type and it is associated with a wide range of lithologies including: (i) intermediate to felsic extrusive volcanics, (ii) intrusive porphyrytic microgranite, (iii) ultramafic volcanic assemblage and (iv) iron rich banded chert. Instead, the mineralisation is highly structurally controled by the Paddy's Flat shear zone which provided fluid-pathways for the mineralising fluid. Regardless of the lithological composition, the mineral assemblage associated with the gold mineralisation consists of quartz, carbonate (ankerite, siderite), sulphides (pyrite, arsenopyrite), fuchsite and sericite assemblage suggesting the introduction of an oxidizing fluid rich in Au, S, As and K ± SiO2. At Paddys Flat the mineralisation is spatially associated with rheologicaly competent units or with domains located at the boundary between rheologically distinct lithologies within the main shear. The fluid pathways provided by the shear zone and the rheological contrast are suggested to be key parameters in the formation of economic lode gold deposit in the Paddy's Flat district.

  18. Cretaceous combined structure in eastern Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Wang, P.; Liu, S.

    2009-12-01

    Eastern Sichuan Basin is confined by two thin-skinned fold-thrust belt, NW-trending Southern Daba Shan (Shan=Mountain) (SDB) in the northeast and NNE- or NE-trending Western XueFeng Shan (WXF) in the southeast, which constitute two convergent salients convex to the inner basin respectively. Although many factors can lead to the formation of fold-thrust belt salients, the eastern Sichuan salients would be attributed to the combined structure (firstly nominated by Chinese geologist, Li Siguang), which means the interaction of two structural belts in the same period. By field surveying and geological map interpreting, we found that WXF deformation began in Late Jurassic along the eastern side of structral belt, where the synclines cored by Upper-Middle Jurassic rock. The initial time of SDB deformation remains poorly determined, however our palaeocurrent data of Lower Cretaceous rock in adjecent foreland basin indicate the provenance from northeast or east. Hence we considered the two fold-thrust belt started interactive in Late Jurassic and mainly combined during Cretaceous. In Early Cretaceous, the front belt of WXF salient arrived near KaiXian where NEE-trending arc-shape folds converged with the NWW-trending arc-shape folds of SDB.The two salients shaped like an westward "open mouth", east of which EW-trending folds of two structural belts juxtaposed. Particularly in the middle belt of WXF (FengJie - WuFeng) the earlier NEE-trending folds were refolded by later NNE-trending folds. We interpret the NEE-trending folds as the front belt of earlier (maybe Late Jurassic) WXF salient. When the two combined fold belts propagated westward together, the original NNE-trending front belt of WXF constrained by the front belt of SDB and formed the curved fold trend lines convex to NNW. Then as WXF deformation continued but SDB gradually terminated, the consequent NNE-trending folds could not be curved and would superpose on the earlier NEE-trending folds.In Late Cretaceous

  19. Miocene and early Pliocene epithermal gold-silver deposits in the northern Great Basin, western United States: Characteristics, distribution, and relationship to Magmatism

    USGS Publications Warehouse

    John, D.A.

    2001-01-01

    Numerous important Miocene and early Pliocene epithermal Au-Ag deposits are present in the northern Great Basin. Most deposits are spatially and temporally related to two magmatic assemblages: bimodal basalt-rhyolite and western andesite. These magmatic assemblages are petrogenetic suites that reflect variations in tectonic environment of magma generation. The bimodal assemblage is a K-rich tholeiitic series formed during continental rifting. Rocks in the bimodal assemblage consist mostly of basalt to andesite and rhyolite compositions that generally contain anhydrous and reduced mineral assemblages (e.g., quartz + fayalite rhyolites). Eruptive forms include mafic lava flows, dikes, cinder and/or spatter cones, shield volcanoes, silicic flows, domes, and ash-flow calderas. Fe-Ti oxide barometry indicates oxygen fugacities between the magnetite-wustite and fayalite-magnetite-quartz oxygen buffers for this magmatic assemblage. The western andesite assemblage is a high K calc-alkaline series that formed a continental-margin are related to subduction of oceanic crust beneath the western coast of North America. In the northern Great Basin, most of the western andesite assemblage was erupted in the Walker Lane belt, a zone of transtension and strike-slip faulting. The western andesite assemblage consists of stratovolcanoes, dome fields, and subvolcanic plutons, mostly of andesite and dacite composition. Biotite and hornblende phenocrysts are abundant in these rocks. Oxygen fugacities of the western andesite assemblage magmas were between the nickel-nickel oxide and hematite-magnetite buffers, about two to four orders of magnitude greater than magmas of the bimodal assemblage. Numerous low-sulfidation Au-Ag deposits in the bimodal assemblage include deposits in the Midas (Ken Snyder), Sleeper, DeLamar, Mule Canyon, Buckhorn, National, Hog Ranch, Ivanhoe, and Jarbidge districts; high-sulfidation gold and porphyry copper-gold deposits are absent. Both high- and low

  20. Early Depositional History of the Eocene Izu-Bonin Mariana Arc, Western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Waldman, R.; Marsaglia, K. M.; Tepley, F. J., III

    2015-12-01

    Expedition 351 of the International Ocean Discovery Program cored an Eocene section at Site U1438 in the Philippine Sea that provides insight into the early history of the Izu-Bonin arc. Subduction here is hypothesized to have initiated spontaneously, leaving a characteristic depositional sequence of post-subduction-initiation localized extension and volcanism. We conducted detailed macroscopic and microscopic study of the cores of the lowermost 100m of volcaniclastic and sedimentary rocks (Unit IV) directly overlying subduction initiation igneous basement, to identify depositional facies and trends. We subdivided Unit IV into three subunits based on lithologic characteristics. Transitions between the subunits are relatively abrupt, occurring within the length of a single core. The lowermost subunit (IVA) consists of 4 meters of laminated pelagic claystone with thin beds of graded volcaniclastic siltstone, and fine-grained tuff laminae composed of plagioclase feldspar and green-brown amphibole. The middle subunit (IVB) comprises 51 meters of texturally variable, thick-bedded, coarse-grained gravity flow deposits. These are composed of volcaniclastic sandstone and conglomerate containing glassy and tachylitic volcanic grains as well as sedimentary lithic fragments, along with traces of shallow-water carbonate bioclasts. Subunit IVB sediments are poorer in feldspar than IVA and contain only trace amphibole. They show variable grain rounding and an upsection increase in vitric components. Tachylite grains range from sub-angular to well rounded throughout, and other volcanic grain types show upward increases in angularity and vesicularity. The abrupt transition from pelagic sediments in subunit IVA to shallow-water-sourced gravity flows in subunit IVB suggests a rapid emergence of shallow-water to subaerial volcanic center early in the arc's development. The upper part of subunit IVB also contains igneous intrusions, providing possible evidence for more proximal

  1. Diagenesis of upper Devonian platform deposits in Emanual Range, Canning basin, western Australia

    SciTech Connect

    Pedone, V.A.; Meyers, W.J.

    1988-02-01

    The Emanuel Range consists of 600 m of peritidal and subtidal carbonate platform deposits of the Pillara Limestone (Givetian-lower Frasnian). Diagenesis of the lower 75 m contrasts markedly with the upper 520 m, principally in the occurrence of extensive dolomite. Formation of extensive secondary porosity by tectonic fracturing, in-situ brecciation, and dissolution of calcitic fossils was enhanced in previously dolomitized strata, exhibiting only minor occurrences in nondolomitized rocks. Formation of secondary porosity occurred over an extended period, marked by a succession of calcite cements, generally following a sequence from slightly ferroan, luminescently zoned cements to nonferroan, nonluminescent cement. Beckite chalcedony and hematite/goethite postdate but are associated with the final calcite cement. The post-dolomite diagenetic sequence suggests initial cementation under reducing burial conditions to final cementation under strongly oxidizing conditions. Fluids moving through the extensive Late carboniferous karst system in the platform may be the diagenetic agent for the later calcites, chalcedony, and iron oxides.

  2. Stratigraphy and reservoir quality of the turbidite deposits, western sag, Bohai bay, China P.R.

    NASA Astrophysics Data System (ADS)

    Rotimi, Oluwatosin J.; Ako, Bankole D.; Zhenli, Wang

    2014-11-01

    Stratigraphic and subtle reservoirs such as pinchouts, sand lenses and unconformities have been discovered in Bohai basin. These reservoirs occur in sub-basins and sag structures called depressions. A prolific depression is the Liaohe depression that has been filled with rapidly changing mixed alluvial fan deposit of the Cenozoic age. Attempts made at recovering residual hydrocarbon from the subtle reservoir have necessitated the re-evaluation of available data to characterize and model the prolific Shahejie Formation turbidite deposit occurring as pinchouts and sand lenses for hydrocarbon assessment, reservoir quality and possible recovery through enhanced methods. Methods employed covered well logs analysis, clustering analysis for electrofacies and fuzzy logic analysis to predict missing log sections. Stratigraphic and structural analysis was done on SEGY 3D seismic volume after seismic to well tie. Stochastic simulation was done on both discrete and continuous upscaled data. This made it possible to correctly locate and laterally track identified reservoir formation on seismic data. Petrophysical parameters such as porosity and permeability were modeled with result of clustering analysis. Result shows that electrofacies converged on 2 rock classes. The area is characterized by the presence of interbeded sand-shale blanket formations serving as reservoir and seal bodies. The reservoir quality of the formations as seen on the petrophysical analysis done is replicated in simulation volume results. Reservoir rocks have porosity between 0.1 and 0.25, permeability between 1 and 2mD and hydrocarbon saturation as high as 89%. Lithofacies are observed to be laterally inconsistent, sub-parallel to dipping and occurring as porous and permeable continuous beds or pinchouts hosting hydrocarbon. The stochastic stratigraphic model depicts rock units in associations that are synsedimentary. The prevalent configuration gotten from the model gave an insight into exploring and

  3. Palynostratigraphy and depositional environment of Vastan Lignite Mine (Early Eocene), Gujarat, western India

    NASA Astrophysics Data System (ADS)

    Rao, M. R.; Sahni, Ashok; Rana, R. S.; Verma, Poonam

    2013-04-01

    Early Eocene sedimentary successions of south Asia, are marked by the development of extensive fossil-bearing, lignite-rich sediments prior to the collision of India with Asia and provide data on contemporary equatorial faunal and vegetational assemblages. One such productive locality in western India is the Vastan Lignite Mine representing approximately a 54-52 Ma sequence dated by the presence of benthic zone marker species, Nummulites burdigalensis burdigalensis. The present study on Vastan Lignite Mine succession is based on the spore-pollen and dinoflagellate cyst assemblages and documents contemporary vegetational changes. 86 genera and 105 species belonging to algal remains (including dinoflagellate cysts), fungal remains, pteridophytic spores and angiospermous pollen grains have been recorded. On the basis of first appearance, acme and decline of palynotaxa, three cenozones have been recognized and broadly reflect changing palaeodepositional environments. These are in ascending stratigraphic order (i) Proxapertites Spp. Cenozone, (ii) Operculodinium centrocarpum Cenozone and (iii) Spinizonocolpites Spp. Cenozone. The basal sequence is lagoonal, palm-dominated and overlain by more open marine conditions with dinoflagellate cysts and at the top, mangrove elements are dominant. The succession has also provided a unique record of fish, lizards, snakes, and mammals.

  4. The Bi'r Tawilah deposit, central western Saudi Arabia: Supergene enrichment of a Pan-African epithermal gold mineralization

    NASA Astrophysics Data System (ADS)

    Surour, Adel A.; Harbi, Hesham M.; Ahmed, Ahmed H.

    2014-01-01

    The Bi'r Tawilah gold deposit in central western Saudi Arabia represents a Pan-African example of gold mineralization in which both hypogene and supergene ores are recorded. The sulphidic gold ore is hosted in intermediate to felsic intrusions that occur along the N-S trending thrust-fault zone within the so-called “Nabitah orogenic zone”. There are four rock units present (from oldest to youngest): serpentinites and related listwaenites, diorites, granitic rocks and porphyries. Hydrothermal alteration consists of chloritization, sericitization, carbonatization and silicification and affects all rock types. Chloritization of biotite results in abundant rutile, whereas sulphidization coincides with carbonatization. The Bi'r Tawilah ore is confined to NW-trending shears (Riedel fractures) related to N-S slip of the pre-existing Tawilah thrust due to activation within the Najd fault system. Samples from the boreholes show macro- and microscopic evidence of shearing such as micro-shear planes and strain shadows of pyrite. Sulphides and gold are present in most rock types. Paragenetically, the sulphides consist of abundant pyrite and relatively lesser amounts of arsenopyrite, in addition to very minor chalcopyrite, sphalerite and galena. In all boreholes, it was noticed that the abundance of arsenopyrite increases with depth. The elevated silver content of electrum (∼13-22 wt%) at Bi'r Tawilah is typical of gold deposits and low-sulphidation epithermal deposits. The early mineralization stage took place in proximity to hydrothermally altered intermediate to felsic intrusions. The aerially restricted hydrothermal alteration by carbon-aqueous fluids led to ore remobilization in which gold amounts up to 4.3 g/t. Finally, gold enrichment (up to 5.4 g/t) resulted from supergene alteration that took place during weathering above the water table at a depth of ∼20-25 m.

  5. Mass transport deposits as witness of Holocene seismic activity on the Ligurian margin, Western Mediterranean (ASTARTE project)

    NASA Astrophysics Data System (ADS)

    Samalens, Kevin; Cattaneo, Antonio; Migeon, Sébastien

    2016-04-01

    The Ligurian Margin (Western Mediterranean) is at the transition between the Southern Alpes and the Liguro-Provençal margin and it is one of the most seismic areas of France. Several historic earthquakes have been indexed; the strongest, on February 23rd, 1887, occurred offshore Menton and Imperia and also caused a tsunami wave. Its equivalent magnitude has been estimated between 6 and 6.5. In addition, a moderate recurrent seismicity shakes the margin. The aim of this study is to understand the link between seismic activity and slope destabilization, and to identify the sedimentary deposits resulting from mass transport or turbidity currents. During Malisar (Geoazur laboratory), Prisme 2 and Prisme 3 (Ifremer) cruises, bathymetry, seafloor imagery (SAR), geophysics data (CHIRP SYSIF and high resolution seismics), and sediment cores have been acquired on the continental slope, focussing on canyons and submarine landslides, and in the basin. These data record numerous mass transport deposits (slump, debrites) in the different physiographic areas of the margin. To search for evidences of past Ligurian margin seismicity during the Holocene, we focused on the northeast part of the margin, the Finale area. We identified and sampled acoustically transparent Mass Transport Deposits up to 20-m thick in the bottom of three coaleshing canyons: Noli, Pora and Centa canyons from W to E in the area offshore Finale Ligure. We also recovered an MTD in the collecting deeper canyon system. MTDs in cores appear as sediment with different degrees of deformation (tilted blocks, slump, debrites) and are topped by hemipelagites. The radiocarbon age of the top of MTDs can be considered synchronous and centered around 4900 yr BP. Mass wasting occurring over more than 50 km of the Ligurian margin could indicate that an earthquake stroke the Finale area sector at that time.

  6. Invisible gold in arsenian pyrite and arsenopyrite from a multistage Archaean gold deposit: Sunrise Dam, Eastern Goldfields Province, Western Australia

    NASA Astrophysics Data System (ADS)

    Sung, Y.-H.; Brugger, J.; Ciobanu, C. L.; Pring, A.; Skinner, W.; Nugus, M.

    2009-10-01

    The Sunrise Dam gold mine (11.1 Moz Au) is the largest deposit in the Archaean Laverton Greenstone Belt (Eastern Goldfields Province, Yilgarn Craton, Western Australia). The deposit is characterized by multiple events of fluid flow leading to repeated alteration and mineralization next to a major crustal-scale structure. The Au content of arsenian pyrite and arsenopyrite from four mineralizing stages (D1, D3, D4a, and D4b) and from different structural and lithostratigraphic environments was measured using in situ laser ablation inductively coupled plasma mass spectrometry. Pyrite contains up to 3,067 ppm Au ( n = 224), whereas arsenopyrite contains up to 5,767 ppm ( n = 19). Gold in arsenopyrite (D4a stage) was coprecipitated and remained as “invisible gold” (nanoparticles and/or lattice-bound) during subsequent deformation events. In contrast, gold in pyrite is present not only as “invisible gold” but also as micrometer-size inclusions of native gold, electrum, and Au(Ag)-tellurides. Pristine D1 and D3 arsenian pyrite contains relatively low Au concentrations (≤26 ppm). The highest Au concentrations occur in D4a arsenian-rich pyrite that has recrystallized from D3 pyrite. Textures show that this recrystallization proceeded via a coupled dissolution-reprecipitation process, and this process may have contributed to upgrading Au grades during D4a. In contrast, Au in D4b pyrite shows grain-scale redistribution of “invisible” gold resulting in the formation of micrometer-scale inclusions of Au minerals. The speciation of Au at Sunrise Dam and the exceptional size of the deposit at province scale result from multiple fluid flow and multiple Au-precipitating mechanisms within a single plumbing system.

  7. Geologic history and palynologic dating of Paleocene deposits, western Rock Springs uplift, Sweetwater County, Wyoming

    USGS Publications Warehouse

    Kirschbaum, M.A.; Nelson, S.N.

    1988-01-01

    During the latest Cretaceous or earliest Paleocene, a northwest-southeast trending anticline developed in the area of the present Rock springs uplift in southwestern Wyoming. This ancestral structure was eroded to a surface of fairly low relief on which a paleosol developed. The surface was formed on the Upper Cretaceous Almond Formation throughout the study area. In the early middle Paleocene (P3 palynomorph zone), topographic lows on the erosion surface were infilled by alluvial deposits that accumulated in channel, floodplain, and backswamp environments. An organic-rich facies contains numerous coal beds and is middle to late Paleocene in age (P3 to P5 zones). The assemblage of pollen that defines the late middle Paleocene (P4 zone) is absent from the area suggesting a hiatus, although no lithologic break was observed at this boundary. The younger organic-poor facies begins in the late Paleocene (P5 zone) and continues to the top of the studied sequence. This change in facies has been used to map the contact between the Fort Union Formation of Paleocene age in this area, and the Wasatch Formation which was though to be of Eocene age. This study demonstrates that, as currently mapped, the lower part of the Wasatch Formation is Paleocene in age. Stratigraphically higher parts of the Wasatch, which presumably contain rocks of latest Paleocene (P6 zone) and earliest Eocene age, were not studied. -Authors

  8. Identification of a late Quaternary alluvial-aeolian sedimentary sequence in the Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Feng, Jin-Liang; Ju, Jian-Ting; Chen, Feng; Hu, Zhao-Guo; Zhao, Xiang; Gao, Shao-Peng

    2016-03-01

    The late Quaternary sedimentary sequence in the northwestern part of the Sichuan Basin consists of five lithological units and with increasing depth include the: Chengdu Clay; Brown Clay; Red Clay; Sandy Silt; and basal Muddy Gravel. The genesis, provenance and age of the sediments, as well as the possible presence of hiatuses within this sequence are debated. Measurements of grain-size, magnetic susceptibility, quartz content, quartz δ18O values, element composition, and Sr-Nd isotopic concentrations of samples from a typical sedimentary sequence in the area provides new insights into the genesis and history of the sequence. The new data confirm that the sediments in study site are alluvial-aeolian in origin, with basal alluvial deposits overlain by aeolian deposits. Like the uppermost Chengdu Clay, the underlying Brown Clay and Red Clay are aeolian in origin. In contrast, the Silty Sand, like the basal Muddy Gravel, is an alluvial deposit and not an aeolian deposit as previously thought. Moreover, the succession of the aeolian deposits very likely contains two significant sedimentary hiatuses. Sedimentological analysis demonstrates that the source materials for the aeolian deposits in the northwestern part of the Sichuan Basin and those on the eastern Tibetan Plateau are different. Furthermore, the loess deposits on the eastern Tibetan Plateau are derived from heterogeneous local sources.

  9. Deposition, Diagenetic, or Bacterial Origin of Magnetite in Sediment Drifts From the Western Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Dulgar, S. E.; Brachfeld, S.; Ishman, S.; Ferré, E. C.

    2007-05-01

    A 607 meter sediment core from the western Antarctic Peninsula was collected during Ocean Drilling Program (ODP) Leg 178 at Site 1096. An abrupt shift, first recognized during the construction of the geomagnetic reversal stratigraphy, is observed in the magnetic mineral assemblage in core 1096A at 18 meters below seafloor (mbsf). This magnetic shift led us to question the fidelity of the geomagnetic reversal record. We evaluated the magnetic mineral assemblage using rock magnetic and electron microscopy techniques. Magnetic susceptibility showed variable concentration of magnetic material with depth, but not an abrupt change in concentration at 18 mbsf. Hysteresis data reveal a grain size shift at 18 mbsf. Magnetic particle size measurements show that with increasing depth the magnetic grain size increases. One possible explanation for the grain size shift is the presence of bacterial magnetite above 18 mbsf. However, TEM analysis did not conclusively prove the presence of magnetosomes. TEM images show grains in the 20-60 nm size range, but these grains were not in chains and they do not have the typical morphologies associated with bacterial magnetite. It is possible that these ultra fine grains are authigenic. Dissolution of these ultra fine magnetic particles could cause the grain size shift, with the smaller grains dissolving below18 mbsf. Temperature dependent FORC analyses are in progress to further characterize the particle size distribution above and below 18 mbsf. Curie temperature analyses indicate that magnetite is present above and below 18 mbsf. A magnetic iron sulfide with a Curie temperature of 350° C is present above 18 mbsf. X-ray microanalysis results agree with Curie temperature analyses, and show the presence of both Ti-poor iron oxides and iron sulfides in the magnetic extract. The presence of magnetic iron sulfides above 18 mbsf suggests iron-sulfur diagenesis is occurring with pyrrhotite preserved above 18 mbsf, and non-magnetic pyrite

  10. A Study of Finding Safer Aquifer in the Arsenic Contaminated Holocene Deposit; South-Western Bangladesh

    NASA Astrophysics Data System (ADS)

    Rahman, M.; Mano, A.; Udo, K.; Ishibashi, Y.

    2009-12-01

    The depositional pattern, geochemistry and mineralogy of the Arsenic (As) contaminated sediments along with the chemistry of groundwaters extracted from the Holocene deposit of an As hotspot, Kalaroa, Southwestern Bangladesh have been investigated in this study. These were done to elucidate a unified view that could explain the accumulation and distribution of As on the sediment surface and its subsequent release into the groundwater. Such view of As distribution mainly helped to find out eventually the possible existence of any safer aquifer that could provide adequate potable water to that targeted community. Two key geochemical parameters, the reaction rate Kr and the partition coefficient, Kd were found to be very promising in explaining the As release mechanism. Showing the realistic natural biotite dissolution process, the in-situ Kr that was derived by applying inverse mass balance model (2.72 × 10-16 /sec), was found to be slower by only three orders of magnitude than that was determined with the laboratory study (3.19×10-13 /sec). A parametric predictor equation, that can calculate the partition coefficient Kd based on the aquifer sediment’s minerals such as Fe and Al contents along with pore-water pH was developed in this study. Another Kd model based on the diffuse double layer surface complexation theory has also been developed to compare the appropriateness of the parametric Kd model. These two models were compared with the in-situ based field Kd data and were found in a good agreement. Integrating those two essential geochemical parameters (Kd and Kr), a 1D-Finite Difference numerical model was applied to observe and evaluate the As pollution scenario for the studied Holocene aquifer. The simulation showed very promising results introducing the idea that the deeper aquifer’s groundwaters would be remained safe against being contaminated with high As in future, due to the presence of a number of encouraging factors. The most significant among

  11. Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

    NASA Astrophysics Data System (ADS)

    Lanfranchini, Mabel Elena; Etcheverry, Ricardo Oscar; de Barrio, Raúl Ernesto; Recio Hernández, Clemente

    2013-04-01

    Precious metal-bearing quartz veins occur at the northeastern sector of the Lago Fontana region in southwestern Argentina, within the context of the Andean continental magmatic arc environment. The deposits and their associated alteration zones are spatially related to a Cretaceous calc-alkaline magmatism represented by silicic dikes and hypabyssal intrusions, and hosted by a Late Jurassic to Cretaceous volcano-sedimentary sequence. The veins and related veinlets crop out discontinuously, in general terms in a NW-SE belt. The primary vein mineral assemblage is composed mostly of pyrite ± galena ± chalcopyrite > hematite ± arsenopyrite in silica gangue minerals. Chemical analyses of grab samples from selected quartz veins show as much as 5.7 ppm Au and 224 ppm Ag, as well as elevated Pb, Cu, and Zn. Hydrothermal fluids caused an innermost silicification and adularia-sericite alteration assemblage, and an external propylitic halo. Sulfur isotope values measured for sulfides (δSS from -1.90 to +1.56‰), and oxygen and hydrogen isotopes measured on quartz crystals and extracted primary fluid inclusion waters (δOO = -2.85 to +5.40‰; δDO = -106.0 to -103.4‰) indicate that mineralization probably formed from magmatic fluids, which were mixed with meteoric waters. Also, fluid inclusion data from quartz veins point out that these fluids had low salinity (1.7-4.2 wt% NaCl equiv.), and temperatures of homogenization between 180 and 325 °C. Mineralogical, petrographic and geochemical features for mineralized surface exposures indicate a typical adularia-sericite, low sulfidation epithermal system in the Lago Fontana area that represents a promising target for further exploration programs.

  12. Evaporite deposition in a shallow perennial lake, Qaidam basin, western China

    SciTech Connect

    Schubel, K.A.; Lowenstein, T.K. ); Spencer, R.J. ); Pengxi, Z. )

    1991-03-01

    Evaporites accumulate in ephemeral saline-pans, shallow perennial lakes or lagoons, and deep perennial systems. Continuous brine trench exposures of Holocene evaporites from the Qaidam basin provide criteria for the recognition of shallow perennial lake sediments. Based on Landsat photographs, lateral extent of beds (at least 7 km), and sequence thicknesses (maximum 2.5 m), the paleolake is interpreted to have been less than 2.5 m deep and at least 120 km{sup 2} in area. Sediments consist of laminated siliciclastic mud overlain by mud-halite couplets (mm- to cm-scale layers), which represent one vertical shallowing- and concentrating-upwards sequence. The basal laminite marks the onset of deposition in this shallow perennial paleolake. Syndepositional halite textures and fabrics in the overlying mud-halite couplets include cumulates, rafts, and chevrons, draped by mud laminae, and halite layers truncated by horizontal dissolution surfaces (increasing in frequency upwards). Paleolake brines, determined from fluid inclusion melting temperatures, are Na-Mg-Cl-rich and evolve from 0.84 m Mg{sup 2} to 1.52 m Mg{sup 2+} (near the surface). Combinations of the following criteria may be used for the recognition of shallow, nonstratified, perennial lake sediments: lateral continuity of layers; muds undisrupted by subaerial exposure; vertical bottom-growth of halite; halite layers conformably overlain by mud; halite layers truncated by nonuniformly spaced horizontal dissolution surfaces; erosional scours and channels filled with cross-laminated gypsum, halite, and siliciclastic sand and mud; and salinity fluctuations over small stratigraphic intervals within an overall concentrating-upwards sequence.

  13. Lithostratigraphy and depositional environments of the Vaqueros Formation in Hondo field, Capitan field, and the western Santa Ynez Mountains, California

    SciTech Connect

    Rigsby, C.A. ); Miles, G.A. ); Schwartz, D.E. )

    1991-02-01

    The Santa Ynez Mountains and the adjacent offshore areas are situated on the northwest edge of the western Transverse Range province. Oligocene-lower Miocene strata in this province record complex interactions among local and regional eustatics and local and regional tectonics and shed light on the sedimentary and tectonic history of this poorly understood region. Correlation of lithofacies units in Oligocene-lower Miocene Vaqueros Formation outcrops the Santa Ynez Mountains with Vaqueros cores from the Hondo and Capital fields leads to the delineation of three major facies tracts within the offshore and coastal areas: fan-delta conglomerates, shoreline sandstones and conglomerates, and inner shelf sandstones. Vaqueros strata at both Hondo and Capital fields are part of the inner shelf sandstone facies tract. Outcrops of the inner shelf facies typically consist of amalgamated packets of locally burrowed, cross-bedded, gravelly sandstones. In outcrop, bioturbation is most common near the tops of the cross-bed sets. In Hondo field a thinner, more basinward portion of this facies is characterized by bioturbated medium- to coarse-grained sandstones. Both in outcrops and at Hondo the base of the Vaqueros is marked by a sharp grain-size change and by a change from interbedded fluvial/deltaic strata below (the Alegria/Sespe formations) to inner shelf strata above (the Vaqueros Formation). The inner shelf facies tract represented by these three localities, fines, thins, and becomes more pervasively bioturbated in the present-day offshore direction suggesting a similar shoreline polarity however, the Oligocene-early Miocene paleogeography is more complex. Facies tracts present in outcrop in the western Santa Ynez Mountains become thinner and coarser in the present-day westerly direction and record deposition on a topographically and geomorphically complex shoreline.

  14. Magnetostratigraphic age and monsoonal evolution recorded by the thickest Quaternary loess deposit of the Lanzhou region, western Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Li, Jijun; Guo, Benhong; Ma, Zhenhua; Li, Xiaomiao; Ye, Xiyan; Yu, Hao; Liu, Jia; Yang, Cheng; Zhang, Shengda; Song, Chunhui; Hui, Zhengchuang; Peng, Tingjiang

    2016-05-01

    The loess-paleosol sequences of the Chinese Loess Plateau (CLP) are major paleoclimatic archives which document the evolution of the East Asian Monsoon (EAM) and changes in the Northern Hemisphere ice sheets during the Quaternary glacial-interglacial cycles. However, the mechanisms regulating the trend of EAM variations on a tectonic scale are unclear. The loess deposits of the western CLP, which have a close relationship with tectonics and climate, are much better-suited to exploring these mechanisms than those of the central CLP. However, studies of long-term EAM evolution from the western CLP have been hindered by the lack of long, accurately-dated sequences with high sediment accumulation rates. Here, we address this problem via high resolution magnetostratigraphic, magnetic susceptibility and grain-size analyses of a 416.2 m-long drill core located at Xijin Village, near Lanzhou. Paleomagnetic dating indicates that the basal age of the Xijin loess is ∼2.2 Ma. The χ and grain-size records reveal that the East Asian Summer Monsoon (EASM) and East Asian Winter Monsoon (EAWM) strengthened synchronously at ∼1.24 Ma. Subsequently, during interglacial periods, the EASM began to penetrate, and then dominate, in the Lanzhou region. This was followed by two stepwise uptrends, commencing at ∼0.87 and ∼0.62 Ma, which resulted in an increasingly moist interglacial climate in the region. We suggest that the uplift of the Tibetan Plateau was largely responsible for these three stepwise enhancements of the EASM. Overall, however, the long-term trend of strengthening in EAWM in the area may have been primarily caused by long-term global cooling from the Late Pliocene onwards.

  15. High energy environment offshore deposits in the western Gulf of Corinth, Greece

    NASA Astrophysics Data System (ADS)

    Beckers, Arnaud; Mortier, Clément; Beck, Christian; Hubert-Ferrari, Aurélia; Reyss, Jean-Louis; Tripsanas, Efthymios; Sakellariou, Dimitris; De Batist, Marc; De Rycker, Koen; Bascou, Pascale; Strivay, David

    2013-04-01

    indicates a high energy environment origin like storm or tsunami. In the Trizonia Sub-Basin, one core located in the center of the Basin shows three clear granulometric peaks at 11, 27 and 53 cm under the seafloor. The coarser fraction of the third one is characterized by numerous organic matter elements. Higher resolution granulometry measurements and other textural parameters (Anisotropy of Magnetic Susceptibility) are needed to understand which processes are responsible for the transport and the deposition of these coarser layers, and to discuss an earthquake-induced origin.

  16. U-Th-Pb ion microprobe analysis of monazite from the Paleoproterozoic Karrat rare earth element (REE) deposit, western Greenland

    NASA Astrophysics Data System (ADS)

    Mott, A.; Grove, M.; Bird, D. K.

    2012-12-01

    The Karrat rare earth element (REE) deposit is located at 72°N on the Niaqornakavsak peninsula of Qeqertarssuq Island on the western coast of Greenland. Metasomatic alteration of an amphibolite host rock by carbonatite derived fluids resulted in REE mineralization in the Karrat Isfjord area. REE in the mineralization are primarily found in bastnasite, allanite, and monazite. In-situ analysis of monazite was conducted on samples obtained from three sites of mineralization: (1) the primary deposit at Niaqornakavsak consisting of a single distinct ~30m thick unit; (2) at Umiamako Nuna 7 km to the east of Niaqornakavsak where the majority of REE mineralization occurs within the first 20m of the surface; and (3) a 6m thick REE-rich vein 100m below the surface at Umiamako Nuna. Formation ages for monazite at Niaqornakavsak, Umiamako Nuna (surface), and Umiamako Nuna (vein) have been calculated using 207Pb/206Pb, 206Pb/238U, and 208Pb/232Th isotope ratios. Multiple isotope ratios were examined to determine the ideal method of monazite analysis based on the inherent issues of low U content of monazite, difficulties measuring 204Pb, common Pb corrections, and peak interferences resulting from high concentrations of REE. 208Pb/232Th analysis resulted in the best precision and smallest spread of values. Energy filtering was applied to 208Pb/232Th analyses in an effort to reduce interferences at several peaks. Although all three isotope ratio analyses result in a Paleoproterozoic age similar to the timing of convergence of the North Atlantic craton, Rae craton, and Aasiat domain as well as the emplacement of the Prøven Igneous Complex in Greenland (1.95-1.80Ga), the values range between 1.7-1.9Ga depending on the isotope ratio.

  17. Multistage amphiboles from the Galinge iron skarn deposit in Qiman Tagh, western China: evidence of igneous rocks replacement

    NASA Astrophysics Data System (ADS)

    Yu, M.; Feng, C.-Y.; Zhu, Y.-F.; Mao, J.-W.; Zhao, Y.-M.; Li, D.-X.

    2016-08-01

    Amphiboles from the Galinge skarn deposit, the largest iron (Fe) polymetallic skarn deposit in the Qiman Tagh metallogenic belt (western China), were formed by multistage fluid-rock interactions. Mineral analysis of the various amphiboles suggest that they were formed by the replacement of mafic to intermediate igneous rocks. The two alteration phases have formed three generations of compositionally distinct amphiboles: Amp-I: Ferro-edenitic hornblende (FE); Amp-II: Deep bluish-green magnesian-hastingsite (MH); Amp-III: Light greenish-beige ferro-actinolite (FA). The Amp-I preserves the primary igneous amphibole composition, and was subsequently replaced by Amp-II. The amphibole Cl content markedly increases from the FE (0.176 - 0.582 wt.%) to the MH (0.894 - 3.161 wt.%), and abruptly drops in the FA (0.017 - 0.039 wt.%). The Cl-rich MH contains the lowest concentration of Si [5.64 - 6.28 atoms per formula unit (apfu)], and the highest (K + Na) values (0.72 - 1.06 apfu) in the amphibole A-site with a high K/(K + Na) of 0.491 to 0.429. Both Mg and Fe contents of the MH and FA vary widely, possibly due to the interactions of magma-derived hydrothermal fluids with the basaltic / andesitic host rocks. Formation of the Cl-rich MH may have been associated with the early high-temperature and high-saline hydrothermal fluids, meanwhile the Cl-poor FA may have formed from later low-temperature and low-saline hydrothermal fluids. The MH plays an important role for consuming Cl carried by hydrothermal fluids. The Cl-rich fluids may have mobilized some elements, such as Fe, Al, Mg, Ca and Ti from the host rocks. Considerable amounts of Ti, Al, Mg and Fe were incorporated into the sphene and Fe-Ti oxides that coexist with the MH.

  18. Comparison of Mercury Mass Loading in Streams to Wet and Dry Atmospheric Deposition in Watersheds of the Western US: Evidence for Non-Atmospheric Mercury Sources

    NASA Astrophysics Data System (ADS)

    Domagalski, J. L.; Majewski, M. S.; Alpers, C. N.; Eckley, C.

    2015-12-01

    Many streams in the western United States (US) are listed as impaired by mercury (Hg), and it is important to understand the magnitudes of the various sources in order to implement management strategies. Atmospheric deposition of Hg and can be a major source of aquatic contamination, along with mine wastes, and other sources. Prior studies in the eastern US have shown that streams deliver less than 50% of the atmospherically deposited Hg on an annual basis. In this study, we compared annual stream Hg loads for 20 watersheds in the western US to measured wet and modeled dry deposition. Land use varies from undisturbed to mixed (agricultural, urban, forested, mining). Data from the Mercury Deposition Network was used to estimate Hg input from precipitation. Dry deposition was not directly measured, but can be modeled using the Community Multi-scale Air Quality model. At an undeveloped watershed in the Rocky Mountains, the ratio of stream Hg load to atmospheric deposition was 0.2 during a year of average precipitation. In contrast, at the Carson River in Nevada, with known Hg contamination from historical silver mining with Hg amalgamation, stream export exceeded atmospheric deposition by a factor of 60, and at a small Sierran watershed with gold mining, the ratio was 70. Larger watersheds with mixed land uses, tend to have lower ratios of stream export relative to atmospheric deposition suggesting storage of Hg. The Sacramento River was the largest watershed for which Hg riverine loads were available with an average ratio of stream Hg export to atmospheric deposition of 0.10. Although Hg was used in upstream historical mining operations, the downstream river Hg load is partially mitigated by reservoirs, which trap sediment. This study represents the first compilation of riverine Hg loads in comparison to atmospheric deposition on a regional scale; the approach may be useful in assessing the relative importance of atmospheric and non-atmospheric Hg sources.

  19. Geologic and geochemical insights into the formation of the Taiyangshan porphyry copper–molybdenum deposit, Western Qinling Orogenic Belt, China

    USGS Publications Warehouse

    Kun-Feng Qiu; Taylor, Ryan D.; Yao-Hui Song; Hao-Cheng Yu; Kai-Rui Song; Nan Li

    2016-01-01

    Taiyangshan is a poorly studied copper–molybdenum deposit located in the Triassic Western Qinling collisional belt of northwest China. The intrusions exposed in the vicinity of the Taiyangshan deposit record episodic magmatism over 20–30 million years. Pre-mineralization quartz diorite porphyries, which host some of the deposit, were emplaced at 226.6 ± 6.2 Ma. Syn-collisional monzonite and quartz monzonite porphyries, which also host mineralization, were emplaced at 218.0 ± 6.1 Ma and 215.0 ± 5.8 Ma, respectively. Mineralization occurred during the transition from a syn-collisional to a post-collisional setting at ca. 208 Ma. A barren post-mineralization granite porphyry marked the end of post-collisional magmatism at 200.7 ± 5.1 Ma. The ore-bearing monzonite and quartz monzonite porphyries have a εHf(t) range from − 2.0 to + 12.5, which is much more variable than that of the slightly older quartz diorite porphyries, with TDM2 of 1.15–1.23 Ga corresponding to the positive εHf(t) values and TDM1 of 0.62–0.90 Ga corresponding to the negative εHf(t) values. Molybdenite in the Taiyangshan deposit with 27.70 to 38.43 ppm Re suggests metal sourced from a mantle–crust mixture or from mafic and ultramafic rocks in the lower crust. The δ34S values obtained for pyrite, chalcopyrite, and molybdenite from the deposit range from + 1.3‰ to + 4.0‰, + 0.2‰ to + 1.1‰, and + 5.3‰ to + 5.9‰, respectively, suggesting a magmatic source for the sulfur. Calculated δ18Ofluid values for magmatic K-feldspar from porphyries (+ 13.3‰), hydrothermal K-feldspar from stockwork veins related to potassic alteration (+ 11.6‰), and hydrothermal sericite from quartz–pyrite veins (+ 8.6 to + 10.6‰) indicate the Taiyangshan deposit formed dominantly from magmatic water. Hydrogen isotope values for hydrothermal sericite ranging from − 85 to − 50‰ may indicate that magma degassing progressively depleted residual liquid in

  20. The origin of manganese-rich metasediments and their relationship to iron formation and base metal deposits, western Georgia piedmont

    SciTech Connect

    Wonder, J.D.

    1987-08-01

    Manganiferous metasediments (coticules), banded iron-formation, and tourmaline-quartz rocks (tourmalinites) are found in close spatial association to each other and to volcanogenic base metal sulfide and gold deposits in the Northern Piedmont of western Georgia. Coticules, which consist of up to 90% garnet and contain from 1 to 15 weight % MnO and 14 to 37 % Fe/sub 2/O/sub 3/, are often hosted by metabasalt. Tourmalinites occur as poorly-bedded aggregates or disseminations and are also found locally associated with metabasalt. Trace element analyses of coticules yield conflicting results. Cu + Co + Ni values and Zr/Cr ratios are low and indicate a hydrothermal origin. Alumina concentrations, Y/P/sub 2/O/sub 5/% ratios, and Th values indicate the probable presence of pelagic sediments in the protolith. Rare earth element patterns are enriched in the light elements and have slight negative Eu anomalies, resembling the patterns of pelagic clays most closely. The protolith of coticules was apparently a hydrothermal sediment with pelagic and/or terrigenous input. Tourmaline in tourmalinites is chemically similar to stratabound sulfide-related examples. Both coticules and tourmalinites are interpreted as metamorphosed seafloor exhalative sediments and thus indicate the potential for the presence of genetically related ore mineralization.

  1. Water on early Mars: Possible subaqueous sedimentary deposits covering ancient cratered terrain in western Arabia and Sinus Meridiani

    NASA Astrophysics Data System (ADS)

    Edgett, Kenneth S.; Parker, Timothy J.

    1997-11-01

    Western Arabia and northern Sinus Meridiani (30 deg N-10 deg S; 40 deg W-40 deg E) are almost entirely covered by wind-eroded, horizontally-bedded, sedimentary layers that lap against local topographic features. This portion of Mars' ancient cratered terrain is relatively low (less than 1 km elevation) and flat (sloping westward 0.7 m/km over 3,000 km). The region lacks valley network channels. We propose that at some time in early Martian history, this region was under water. The water hypothesis is strengthened by the presence of (1) a shore-like contact between smooth-surfaced deposits and ancient cratered terrain in central Sinus Meridiani, (2) polygonal structures in northern Sinus Meridiani, and (3) sand (which cannot be from airfall), possibly reworked by wind from the underlying sedimentary units. The September 1997 arrival of Mars Global Surveyor's thermal emission spectrometer offers an opportunity to begin to test this hypothesis by searching for carbonate and evaporite minerals among the sediment covering the region.

  2. A modified genetic model for the Huangshandong magmatic sulfide deposit in the Central Asian Orogenic Belt, Xinjiang, western China

    NASA Astrophysics Data System (ADS)

    Mao, Ya-Jing; Qin, Ke-Zhang; Li, Chusi; Tang, Dong-Mei

    2015-01-01

    The Huangshandong Ni-Cu deposit is the largest magmatic sulfide deposit discovered to date in the Central Asian Orogenic Belt in northern Xinjiang, western China. The host intrusion is a 274-Ma composite mafic-ultramafic intrusion consisting of four separate intrusive units: a large layered gabbroic sequence (phase I), a sheet-like ultramafic body (phase II), a dyke-like gabbronorite body (phase III), and an irregular ultramafic unit (phase IV). Important sulfide mineralization is present in the last three intrusive units, predominantly as disseminated and net-textured sulfides (pyrrhotite, pentlandite, and chalcopyrite). The Huangshandong mafic-ultramafic intrusive rocks are characterized by arc-like geochemical signatures such as low Ca content in olivine and negative Nb-Ta anomalies in whole rocks. This, together with a post-subduction setting for the East Tianshan in the Permian, suggests that the source mantle was modified previously by slab-derived fluids in the Carboniferous. The mantle-derived magma was ponded in a staging chamber in the lower part of the newly formed arc crust. The first batch of magma to arrive at Huangshandong was most fractionated and depleted in Ni, crystallizing Fe-rich and Ni-depleted olivine (Fo67, <300 ppm Ni). The second batch of magma was more primitive, crystallizing more primitive olivine (Fo81-84). The third batch of magma was also highly fractionated and depleted in Ni, crystallizing Fe-rich and Ni-depleted olivine (Fo72, ~600 ppm Ni). The final batch of magma became more primitive again, crystallizing the most primitive olivine (Fo81-86). The occurrence of rounded sulfide inclusions in olivine primocrysts in the Huangshandong ultramafic rocks indicates that immiscible sulfide liquid droplets were present during olivine crystallization. The Ni tenors of disseminated sulfide ores in the gabbronorite dyke vary mainly between 5 and 8 wt%, which are too high to have been produced by the parental magma of the dyke. The Ni, Cu, and

  3. Epithermal gold-siver deposits in the western United States: time-space products of evolving plutonic, volcanic and tectonic environments

    USGS Publications Warehouse

    Berger, B.R.; Bonham, H.F., Jr.

    1990-01-01

    The western United States has been the locus of considerable subaerial volcanic and plutonic igneous activity since the mid-Mesozoic. After the destruction of the Jurassic-Cretaceous magmatic arc-trench system, subduction was re-established in the Late Mesozoic with low-angle underthrusting of the oceanic plate beneath western North America. This resulted in crustal shortening during the Late Cretaceous to Early Tertiary and removal of the mantle lithosphere west of the Rocky Mountains. Commencing in the Eocene, flat subduction ceased, the volcanic arc began to re-establish itself along the continental margin, and the hingeline along the steepening subducting plate migrated from east to west. The crust east of the migrating hingeline was exposed to hot asthenosphere, and widespread tectonics and volcanic activity resulted. Hydrothermal activity accompanied the volcanism resulting in numerous epithermal gold-silver deposits. The temporal and spatial distributions of epithermal deposits in the region are therefore systematic and can be subdivided into discrete time intervals which are related to widespread changes in magmatic activity. Time intervals selected for discussion are Pre-Cenozoic, 66-55 Ma, 54-43 Ma, 42-34 Ma, 33-24 Ma, 23-17 Ma, and <17 Ma. Many of these intervals contain both sedimentary-rock and two varieties of volcanic-rock hosted deposits (adularia-sericite and alunite-kaolinite ?? pyrophyllite). Continental rifting is important to the formation of deposits, and, within any given region, it is at the initiation of deep rifting that alunite-kaolinite ?? pyrophyllite type epithermal deposits are formed. Adularia-sericite type deposits are most common, being related to all compositions and styles of volcanic activity. Therefore, the volcano-tectonic context of the western United States provides a unified framework in which to understand and explore for epithermal type deposits. ?? 1990.

  4. Late Quaternary sediment deposition of core MA01 in the Mendeleev Ridge, the western Arctic Ocean: Preliminary results

    NASA Astrophysics Data System (ADS)

    Park, Kwang-Kyu; Kim, Sunghan; Khim, Boo-Keun; Xiao, Wenshen; Wang, Rujian

    2014-05-01

    Late Quaternary deep marine sediments in the Arctic Ocean are characterized by brown layers intercalated with yellowish to olive gray layers (Poore et al., 1999; Polyak et al., 2004). Previous studies reported that the brown and gray layers were deposited during interglacial (or interstadial) and glacial (or stadial) periods, respectively. A 5.5-m long gravity core MA01 was obtained from the Mendeleev Ridge in the western Arctic Ocean by R/V Xue Long during scientific cruise CHINARE-V. Age (~450 ka) of core MA01 was tentatively estimated by correlation of brown layers with an adjacent core HLY0503-8JPC (Adler et al., 2009). A total of 22 brown layers characterized by low L* and b*, high Mn concentration, and abundant foraminifera were identified. Corresponding gray layers are characterized by high L* and b*, low Mn concentration, and few foraminiferal tests. Foraminifera abundance peaks are not well correlated to CaCO3 peaks which occurred with the coarse-grained (>0.063 mm) fractions (i.e., IRD) both in brown and gray layers. IRDs are transported presumably by sea ice for the deposition of brown layers and by iceberg for the deposition of gray layers (Polyak et al., 2004). A strong correlation coefficient (r2=0.89) between TOC content and C/N ratio indicates that the major source of organic matter is terrestrial. The good correlations of CaCO3 content to TOC (r2=0.56) and C/N ratio (r2=0.69) imply that IRDs contain detrital CaCO3 which mainly originated from the Canadian Arctic Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond to CaCO3 peaks, which suggests that the fine-grained particles in the Mendeleev Ridge are transported from the north coast Alaska and Canada where Mesozoic and Cenozoic strata are widely distributed. Thus, the Beaufort Gyre, the predominant surface current in the western Arctic Ocean, played an important role in the sediment delivery to the Mendeleev Ridge. It is worthy of note that the TOC and CaCO3 peaks are

  5. Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin

    USGS Publications Warehouse

    Parsons, T.; Ji, C.; Kirby, E.

    2008-01-01

    On 12 May 2008, the devastating magnitude 7.9 (Wenchuan) earthquake struck the eastern edge of the Tibetan plateau, collapsing buildings and killing thousands in major cities aligned along the western Sichuan basin in China. After such a large-magnitude earthquake, rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. The mainshock of the 12 May earthquake ruptured with as much as 9 m of slip along the boundary between the Longmen Shan and Sichuan basin, and demonstrated the complex strike-slip and thrust motion that characterizes the region. The Sichuan basin and surroundings are also crossed by other active strike-slip and thrust faults. Here we present calculations of the coseismic stress changes that resulted from the 12 May event using models of those faults, and show that many indicate significant stress increases. Rapid mapping of such stress changes can help to locate fault sections with relatively higher odds of producing large aftershocks. ??2008 Macmillan Publishers Limited. All rights reserved.

  6. Three dimensional surface slip partitioning of the Sichuan earthquake from Synthetic Aperture Radar

    NASA Astrophysics Data System (ADS)

    de Michele, M.; Raucoules, D.; de Sigoyer, J.; Pubellier, M.; Lasserre, C.; Pathier, E.; Klinger, Y.; van der Woerd, J.

    2009-12-01

    The Sichuan earthquake, Mw 7.9, struck the Longmen Shan range front, in the western Sichuan province, China, on 12 May 2008. It severely affected an area where little historical seismicity and little or no significant active shortening were reported before the earthquake (e.g. Gu et al., 1989; Chen et al., 1994; Gan et al., 2007). The Longmen Shan thrust system bounds the eastern margin of the Tibetan plateau and is considered as a transpressive zone since Triassic time that was reactivated during the India-Asia collision (e.g., Tapponnier and Molnar, 1977, Chen and Wilson 1996; Arne et al., 1997, Godard et al., 2009). However, contrasting geological evidences of sparse thrusting and marked dextral strike-slip faulting during the Quaternary along with high topography (Burchfiel et al., 1995; Densmore et al., 2007) have led to models of dynamically driven and sustained topography (Royden et al., 1997) limiting the role of earthquakes in relief building and leaving the mechanism of long term strain distribution in this area as an open question. Here we combine C and L band Synthetic Aperture Radar (SAR) offsets data from ascending and descending paths to retrieve the three dimensional surface slips distribution all along the earthquake ruptures of the Sichuan earthquake. We show a quantitative assessment of the amount of co-seismic slip and its partitioning at the surface.

  7. Three-dimensional seismic velocity structure in the Sichuan basin, China

    NASA Astrophysics Data System (ADS)

    Wang, Maomao; Hubbard, Judith; Plesch, Andreas; Shaw, John H.; Wang, Lining

    2016-02-01

    We present a new three-dimensional velocity model of the crust in the eastern margin of the Tibetan Plateau. The model describes the velocity structure of the Sichuan basin and surrounding thrust belts. The model consists of 3-D surfaces representing major geologic unit contacts and faults and is parameterized with Vp velocity-depth functions calibrated using sonic logs. The model incorporates data from 1166 oil wells, industry isopach maps, geological maps, and a digital elevation model. The geological surfaces were modeled based on structure contour maps for various units from oil wells and seismic reflection profiles. These surfaces include base Quaternary, Mesozoic, Paleozoic, and Proterozoic horizons. The horizons locally exhibit major offsets that are compatible with the locations and displacements of important faults systems. This layered, upper crustal 3-D model extends down to 10-15 km depth and illustrates lateral and vertical variations of velocity that reflect the complex evolution of tectonics and sedimentation in the basin. The model also incorporates 3-D descriptions of Vs and density for sediments that are obtained from empirical relationships with Vp using direct measurements of these properties in borehole logs. To illustrate the impact of our basin model on earthquake hazards assessment, we use it to calculate ground motions and compare these with observations for the 2013 Lushan earthquake. The result demonstrates the effects of basin amplification in the western Sichuan basin. The Sichuan CVM model is intended to facilitate fault systems analysis, strong ground motion prediction, and earthquake hazards assessment for the densely populated Sichuan region.

  8. Mid-Proterozoic detrital zircons and the depositional history of the Jack Hills (Narryer Gneiss Complex, Western Australia)

    NASA Astrophysics Data System (ADS)

    Bell, E. A.; Harrison, T. M.; Mojzsis, S. J.

    2012-12-01

    Quartz-biotite schists ("metaconglomerates" s.l.) in the Jack Hills outcrops of the Narryer Terrane of Western Australia host detrital >4 Ga zircons. These rocks are presumed to have been deposited at about 3 Ga and subsequently experienced metamorphism and granite intrusion at 2.45-2.6 Ga. Protoliths of the oldest detrital zircon population (>3.8 Ga) have not yet been identified, and the post-2.6 Ga history of the Jack Hills remains murky. Rare metavolcanic units are documented at ca. 1.8-1.9 Ga. Some metasediments near the Hadean zircon "discovery" site that are apparently young enough to have incorporated mid-Proterozoic detrital zircons are evidence of further geologic activity, although it is possible that these rocks were tectonically juxtaposed later. To further resolve the Proterozoic history of the Jack Hills, we report U-Pb age data for 60 detrital zircons extracted from two quartzites from the eastern Jack Hills (~50 km distant from the "discovery" site of Hadean zircons); in this sample suite 26 concordant zircons range in age from 0.168-3.49 Ga, with an age peak at ca. 2.6 Ga and a scattering of ages from 1.06-2.0 Ga. Zircon sources <1.8 Ga have not so far been identified in the Narryer Terrane and may point to far-field sediment transport. Several ca. 1.07 Ga zircons may derive from the Warakurna Large Igneous Province of the same age, which extends through much of central and Western Australia. One concordant zircon with a 206Pb/238U age of 0.166±6 Ga displays a patchy internal texture indicative of alteration; all other concordant grains are >1.06 Ga. Only 2 concordant zircons display ages >3 Ga, unlike the dominant mid-Archean signature from other reported Proterozoic sediments in the Jack Hills. All told, these quartzites display a significantly different provenance than other previously studied units from the terrane, with decreased importance of mid-Archean zircon sources and significantly younger (<1.06 Ga) ages of sedimentation than

  9. Genesis of superimposed hypogene and supergene Fe orebodies in BIF at the Madoonga deposit, Yilgarn Craton, Western Australia

    NASA Astrophysics Data System (ADS)

    Duuring, Paul; Hagemann, Steffen

    2013-03-01

    The Madoonga iron ore body hosted by banded iron formation (BIF) in the Weld Range greenstone belt of Western Australia is a blend of four genetically and compositionally distinct types of high-grade (>55 wt% Fe) iron ore that includes: (1) hypogene magnetite-talc veins, (2) hypogene specular hematite-quartz veins, (3) supergene goethite-hematite, and (4) supergene-modified, goethite-hematite-rich detrital ores. The spatial coincidence of these different ore types is a major factor controlling the overall size of the Madoonga ore body, but results in a compositionally heterogeneous ore deposit. Hypogene magnetite-talc veins that are up to 3 m thick and 50 m long formed within mylonite and shear zones located along the limbs of isoclinal, recumbent F1 folds. Relative to least-altered BIF, the magnetite-talc veins are enriched in Fe2O3(total), P2O5, MgO, Sc, Ga, Al2O3, Cl, and Zr; and depleted in SiO2 and MnO2. Mafic igneous countryrocks located within 10 m of the northern contact of the mineralised BIF display the replacement of primary igneous amphibole and plagioclase, and metamorphic chlorite by hypogene ferroan chlorite, talc, and magnetite. Later-forming, hypogene specular hematite-quartz veins and their associated alteration halos partly replace magnetite-talc veins in BIF and formed during, to shortly after, the F2-folding and tilting of the Weld Range tectono-stratigraphy. Supergene goethite-hematite ore zones that are up to 150 m wide, 400 m long, and extend to depths of 300 m replace least-altered BIF and existing hypogene alteration zones. The supergene ore zones formed as a result of the circulation of surface oxidised fluids through late NNW- to NNE-trending, subvertical brittle faults. Flat-lying, supergene goethite-hematite-altered, detrital sediments are concentrated in a paleo-topographic depression along the southern side of the main ENE-trending ridge at Madoonga. Iron ore deposits of the Weld Range greenstone belt record remarkably similar

  10. Porphyry Cu-Au and associated polymetallic Fe-Cu-Au deposits in the Beiya Area, western Yunnan Province, south China

    USGS Publications Warehouse

    Xu, X.-W.; Cai, X.-P.; Xiao, Q.-B.; Peters, S.G.

    2007-01-01

    The Alkaline porphyries in the Beiya area are located east of the Jinshajiang suture, as part of a Cenozoic alkali-rich porphyry belt in western Yunnan. The main rock types include quartz-albite porphyry, quartz-K-feldspar porphyry and biotite-K-feldspar porphyry. These porphyries are characterised by high alkalinity [(K2O + Na2O)% > 10%], high silica (SiO2% > 65%), high Sr (> 400??ppm) and 87Sr/86Sr (> 0.706)] ratio and were intruded at 65.5??Ma, between 25.5 to 32.5??Ma, and about 3.8??Ma, respectively. There are five main types of mineral deposits in the Beiya area: (1) porphyry Cu-Au deposits, (2) magmatic Fe-Au deposits, (3) sedimentary polymetallic deposits, (4) polymetallic skarn deposits, and (5) palaeoplacers associated with karsts. The porphyry Cu-Au and polymetallic skarn deposits are associated with quartz-albite porphyry bodies. The Fe-Au and polymetallic sedimentary deposits are part of an ore-forming system that produced considerable Au in the Beiya area, and are characterised by low concentrations of La, Ti, and Co, and high concentrations of Y, Yb, and Sc. The Cenozoic porphyries in western Yunnan display increased alkalinity away from the Triassic Jinshajiang suture. Distribution of both the porphyries and sedimentary deposits in the Beiya area are interpreted to be related to partial melting in a disjointed region between upper mantle lithosphere of the Yangtze Plate and Gondwana continent, and lie within a shear zone between buried Palaeo-Tethyan oceanic lithosphere and upper mantle lithosphere, caused by the subduction and collision of India and Asia. ?? 2006 Elsevier B.V. All rights reserved.

  11. Pliocene-Quaternary contourite depositional system along the south-western Adriatic margin: changes in sedimentary stacking pattern and associated bottom currents

    NASA Astrophysics Data System (ADS)

    Pellegrini, Claudio; Maselli, Vittorio; Trincardi, Fabio

    2016-02-01

    The Pliocene-Quaternary history of the south-western Adriatic margin, represented by a complex contourite depositional system, records the palaeoceanography of the basin and the interactions between oceanographic processes and the uneven slope morphology that resulted from tectonic deformation. Three main stages can be recognized: (1) during the Pliocene, a giant sediment drift formed on the southern flank of the slope-transverse Gondola anticline that focused and accelerated the flow of slope-parallel bottom currents; (2) since the early to middle Pleistocene transition, a reorganization of bottom-current pathways led to a sharp change in the sedimentary architecture of the margin that became dominated by the growth of contourite deposits; (3) as of 350 ka, landward-migrating contourites on the outer shelf (less than 120 m water depth) reflect the presence of bottom currents also in shallow waters. This analysis of the sedimentary stacking pattern of the contourite depositional system that developed along the south-western Adriatic margin since the Pliocene enables disentangling the processes that controlled changes in bottom-current activity, demonstrating that bottom-current deposits constitute the bulk of depositional sequences at the Milankovitch timescale.

  12. Mineralogical study of sediment-hosted gold deposits in the Yangshan ore field, Western Qinling Orogen, Central China

    NASA Astrophysics Data System (ADS)

    Liang, Jinlong; Sun, Weidong; Zhu, Sanyuan; Li, He; Liu, Yulong; Zhai, Wei

    2014-05-01

    The Yangshan gold ore field is located in the southern subzone of the Western Qinling Orogen. Mineralization is confined by the east-west-striking Anchanghe thrust fault zone. These subparallel faults constitute a branch of the regional Mianlue structural zone, crosscutting Middle Devonian carbonaceous carbonate and clastic rock sequences, an ore-bearing unit locally named the Sanhekou Formation. The metasedimentary clastic and carbonate rocks containing fine-grained sulfides are the main host rocks of the deposit, with minor mineralization occurring as coarse-grained pyrite-quartz veinlets in black shale and as dissemination in some plagiogranite dykes. Electron microprobe (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses show that arsenian pyrite and arsenopyrite are the major hosts for gold with tens of ppm up to weight percent levels of Au, and the Au contents in arsenopyrite are one order of magnitude higher than those in pyrite. A negative correlation of As and S in arsenian pyrite is consistent with the substitution of As for S in the mineral. Both arsenian pyrite and arsenopyrite in the Yangshan ore field show chemical zonations with middle parts (mantle) enriched in As and Au relative to cores and the outermost rims, reflecting the chemical evolution of ore-forming fluids. High resolution transmission electron microscopy (HRTEM) analysis failed to identify any nanoparticle of native gold even in the highest Au parts of arsenopyrite. This observation combined with the relatively homogenous distribution of Au, a positive correlation of As and Au, and Au/As ratios below the solubility limit of gold in arsenian pyrite and arsenopyrite, suggests that invisible gold is likely present as structurally bound Au+1 in sulfides, although our work cannot exclude the existence of Au nanoparticles in arsenian pyrite as identified in American Carlin-type gold deposits. Submicron native gold may be much more easily found in

  13. [Spatial distribution and ecological significance of heavy metals in soils from Chatian mercury mining deposit, western Hunan province].

    PubMed

    Sun, Hong-Fei; Li, Yong-Hu; Ji, Yan-Fang; Yang, Lin-Sheng; Wang, Wu-Yi

    2009-04-15

    Ores, waste tailings and slag, together with three typical soil profiles (natural soil profiles far from mine entrance and near mine entrance, soil profile under slag) in Chatian mercury mining deposit (CMD), western Hunan province were sampled and their concentrations of mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), zinc (Zn) were determined by HG-ICP-AES and ICP-MS. Enrichment factor and correlation analysis were taken to investigate the origins, distribution and migration of Hg, as well as other heavy metals in the CMD. The results show that Hg is enriched in the bottom of the soil profile far from mine entrance but accumulated in the surface of soil profiles near mine entrance and under slag. The soil profiles near mine entrance and under slag are both contaminated by Hg, while the latter is contaminated more heavily. In the soil profile under slag, Hg concentration in the surface soil, Hg average concentration in the total profile, and the leaching depth of soil Hg are 640 microg x g(-1), (76.74 +/- 171.71) microg x g(-1), and more than 100 cm, respectively; while 6.5 microg x g(-1), (2.74 +/- 1.90) microg x g(-1), and 40 cm, respectively, are found in the soil profile near mine entrance. Soil in the mercury mine area is also polluted by Cd, As, Pb, Zn besides metallogenic element Hg, among which Cd pollution is relatively heavier than others. The mobility of the studied heavy metals in soil follows the order as Hg > Cd > As > Zn approximately equal to Pb. The leaching depth of the heavy metals is influenced by total concentration in the surface soil and soil physico-chemical parameters. The origins, distribution and migration of heavy metals in soil profile in the mining area are related to primary geological environment, and strongly influenced by human mining activities. PMID:19545023

  14. Franciscan olistoliths in Upper Cretaceous conglomerate deposits, Western Transverse Ranges, California: Implications for basin morphology and tectonic history

    SciTech Connect

    Reed, W.E.; Campbell, M.D. . Dept. of Earth and Space Sciences)

    1993-04-01

    Compositional analyses reveal that Upper Cretaceous sediments exposed in the Western Transverse Ranges of CA were deposited in submarine fan systems in a forearc basin. Point count data suggest a magmatic arc/recycled orogen as the dominant provenance for these sediments. Paleocurrent measurements from conglomerates in these sediments yield a northerly transport direction. Removal of ca. 90[degree] of clockwise rotation and 70 km of right-lateral slip restore this section to a position west of the San Diego area. The forearc basin would have had a N-S orientation, with the bulk of sediments supplied by the Peninsular Ranges to the east. Evidence of the erosion of the accretionary wedge is provided by the presence of large, internally stratified olistoliths of Franciscan material interbedded with and surrounded by upper Cretaceous conglomerate. Petrographic, quantitative SEM, and microprobe analyses indicate the presence of diagnostic Franciscan mineralogy, including glaucophane, riebeckite, lawsonite, and serpentine. Olistoclasts of chert, jadeitic graywacke, serpentine, and blueschist are found intermixed with the conglomerates in close association with the olistoliths. This association provides strong field evidence that recirculation of melange material within the subduction zone was active and well-established by late Cretaceous time. Inferences regarding the forearc system morphology can be drawn from these observations. The occurrence of coarse, easterly-derived conglomerates surrounded by large, stratified, but sheared, westerly-derived Franciscan debris, suggests a narrow, relatively steep-sided basin. Paleocurrent measurements gave no indication of axial transport within the basin. This morphology suggests that, in late Cretaceous time, the forearc basin was youthful, with a narrow arc-trench gap. Thus, relative convergence rates between the North American and Pacific plates were possibly slower than Tertiary convergence rates.

  15. Sedimentary Deposits from the 17 July 2006 Western Java Tsunami, Indonesia: Use of Grain Size Analyses to Assess Tsunami Flow Depth, Speed, and Traction Carpet Characteristics

    NASA Astrophysics Data System (ADS)

    Moore, Andrew; Goff, James; McAdoo, Brian G.; Fritz, Hermann M.; Gusman, Aditya; Kalligeris, Nikos; Kalsum, Kenia; Susanto, Arif; Suteja, Debora; Synolakis, Costas E.

    2011-11-01

    The 2006 western Java tsunami deposited a discontinuous sheet of sand up to 20 cm thick, flooded coastal southern Java to a depth of at least 8 m and inundated up to 1 km inland. In most places the primarily heavy mineral sand sheet is normally graded, and in some it contains complex internal stratigraphy. Structures within the sand sheet probably record the passage of up to two individual waves, a point noted in eyewitness accounts. We studied the 2006 tsunami deposits in detail along a flow parallel transect about 750 m long, 15 km east of Cilacap. The tsunami deposit first becomes discernable from the underlying sediment 70 m from the shoreline. From 75 to 300 m inland the deposit has been laid down in rice paddies, and maintains a thickness of 10-20 cm. Landward of 300 m the deposit thins dramatically, reaching 1 mm by 450 m inland. From 450 m to the edge of deposition (around 700 m inland) the deposit remains <1 mm thick. Deposition generally attended inundation—along the transect, the tsunami deposited sand to within about 40 m of the inundation limit. The thicker part of the deposit contains primarily sand indistinguishable from that found on the beach 3 weeks after the event, but after about 450 m (and roughly coinciding with the decrease in thickness) the tsunami sediment shifts to become more like the underlying paddy soil than the beach sand. Grain sizes within the deposit tend to fine upward and landward, although overall upward fining takes place in two discrete pulses, with an initial section of inverse grading followed by a section of normal grading. The two inversely graded sections are also density graded, with denser grains at the base, and less dense grains at the top. The two normally graded sections show no trends in density. The inversely graded sections show high density sediment to the base and become less dense upward and represents traction carpet flows at the base of the tsunami. These are suggestive of high shear rates in the flow

  16. Depositional evolution of the Early Cretaceous Sihetun Lake and implications for regional climatic and volcanic history in western Liaoning, NE China

    NASA Astrophysics Data System (ADS)

    Jiang, Baoyu; Fürsich, Franz T.; Hethke, Manja

    2012-06-01

    Numerous well-known fossils of the Jehol Biota, including early birds, feathered theropods, primitive mammals, and putative early angiosperms, have been discovered in lacustrine deposits (Lake Sihetun) of the Lower Cretaceous Yixian Formation of western Liaoning province, NE China. Based on extensive field investigations and four high-resolution excavations, we document in detail the spatio-temporal changes of sedimentary facies, facies associations and limnic community relicts, reconstruct the depositional history, and discuss the significance of these deposits regarding the regional climatic and volcanic history. Four phases are recognized in the history of Lake Sihetun. They are: (1) a phase of fluctuating but gradually rising water level indicated by subaerial and shallow-water lacustrine deposits, (2) a lake with beach-nearshore facies along the marginal areas and suspension-dominated lake floor facies in central areas, (3) a lake phase with a lake floor dominated by hyperpycnal flows, and (4) progradation of a fan delta. Two distinct depositional conditions are observed: stratified and unstratified lake intervals. The former occurred mainly during the second phase and produced clay-poor and clay-rich laminae, whereas the latter developed during the other three phases, and were dominated by deposition of subaqueous sedimentary density flows. These alternations of depositional conditions in offshore lacustrine deposits suggest that the Yixian Formation may have formed under a transitional climate regime fluctuating gradually from warm and dry to warm and humid conditions. Resurgent volcanism is inferred to have become stronger during the late phase of lake development based on distribution of deposits characterizing the unstratified lake interval and volcanic rocks of the overlying Upper Lava unit, a higher content of primary pyroclastic fragments, and evidence of strong syndepositional disturbance.

  17. Use of passive sampling methods and models to understand sources of mercury deposition to high elevation sites in the Western United States.

    PubMed

    Huang, Jiaoyan; Gustin, Mae Sexauer

    2015-01-01

    To understand gaseous oxidized mercury (GOM) sources to the Western US, data were collected with passive samplers for ambient GOM concentrations and dry deposition at 10 sites from the coast of the Pacific Ocean to Great Basin National Park. Tests were done to better understand the samplers and the materials used. Measured dry deposition of GOM was significantly higher at sites >2000 m elevation relative to those below due to high GOM concentrations and atmospheric turbulence. At these high elevation sites, GOM dry deposition was higher in spring due to long-range transport from Asia (air parcels from the free troposphere) and some high GOM dry deposition events were related to regional emissions. Dry deposition of GOM at two sites was calculated using the passive sampler data and a multiple-resistance model. A previously developed relationship between the sampling rate of the passive sampler and GOM concentrations was used to estimate dry deposition and a scaling factor of 3 was used to adjust GOM concentrations, due to underestimation by KCl-coated denuder measurements. With the scaling factor of 3, modeled deposition was in the range of results estimated from two different models settings. However, dry deposition did not correlate consistently with either model. The disagreement could be due to uncertainties associated with measurements and/or modeling, or different GOM compounds existing in the atmosphere. If the atmospheric GOM compounds are known, dry deposition velocities could be estimated more accurately. Lastly, we investigated the potential for use of a new sampling material for GOM and checked the efficiency of the passive sampler. PMID:25485926

  18. Substrate-independent feeding mode of the ichnogenus Phymatoderma from the Lower Jurassic shelf-sea deposits of central and western Europe

    NASA Astrophysics Data System (ADS)

    Izumi, Kentaro; Rodríguez-Tovar, Francisco J.; Piñuela, Laura; García-Ramos, José Carlos

    2014-10-01

    Deposit-feeding strategies recorded in the ichnogenus Phymatoderma from the Lower Jurassic shelf-sea deposits in central (Dotternhausen, southwest Germany) and western Europe (Asturias, north Spain) are revealed by geochemical and microscopic analyses. Thin-section observations showed that the trace-maker of Phymatoderma from Asturias ingested bioclastic skeletal sediments, and that from Dotternhausen ingested fine-grained siliciclastic sediments. Geochemical analysis elucidated that the trace-makers of Phymatoderma from both Asturias and Dotternhausen were non-selective deposit feeders (i.e., indiscriminately ingesting sediment particles on the seafloor), although the ingested sediments were significantly different in lithology. Microscopic analysis revealed that the Early Jurassic Phymatoderma-producers mainly fed on calcareous nannoplankton, i.e., coccolithophores, dinoflagellates, as well as their phytodetritus. Here, we demonstrate a substrate-independent feeding mode in the Early Jurassic Phymatoderma-producers, which accords with the similar morphologic, paleogeographic, and chronologic context of Phymatoderma from Asturias and Dotternhausen.

  19. Helicopter EM (ZTEM-VTEM) survey results over the Nuqrah copper-lead-zinc-gold SEDEX massive sulphide deposit in the Western Arabian Shield, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Legault, Jean M.; Izarra, Carlos; Prikhodko, Alexander; Zhao, Shengkai; Saadawi, Emad M.

    2015-10-01

    Magnetic and electromagnetic (EM) results from two helicopter EM surveys, a time-domain (VTEM) and AFMAG (ZTEM), are compared over the Nuqrah sedimentary exhalative (SEDEX) massive sulphide deposits in the Western Arabian Shield of the Kingdom of Saudi Arabia. The magnetic and EM data from both surveys map the major controlling structures that host the Nuqrah North and South deposits. Neither Nuqrah deposits stand out as distinctive aeromagnetic anomalies, but both EM surveys define the massive sulphide mineralised vent and bedded portions of the SEDEX orebodies. ZTEM is interpreted to be more capable in defining the larger, lower conductance and less mineralised distal portions of the SEDEX system. The modelled ZTEM also defines a down-dip extension of the Nuqrah South zone below a depth of 750 m.

  20. Study on 3-D velocity structure of crust and upper mantle in Sichuan-yunnan region, China

    USGS Publications Warehouse

    Wang, C.; Mooney, W.D.; Wang, X.; Wu, J.; Lou, H.; Wang, F.

    2002-01-01

    Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others appear the characteristic of tectonic boundary, indicating that the faults litely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the Sichuan-Yunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the Indian and the Asian plates. The crustal velocity in the Sichuan-Yunnan rhombic block generally shows normal.value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

  1. Geochronology of the western and central Brooks Range, Alaska: Implications for the geologic evolution of the Anarraaq and Red Dog Zn-Pb-Ag deposits

    USGS Publications Warehouse

    Rombach, C.S.; Layer, P.W.

    2004-01-01

    A compilation of published geochronology of rocks and minerals from the western and central Brooks Range provides a framework for understanding the complex history of the Brooks Range and northern Alaska. A simplified timeline of events comprises (1) Devonian extension, (2) Mississippian extension and Zn-Pb-Ag mineralization, (3) a passive interval, (4) pre-Brooks Range orogeny rock-formation and thermal event, (5) inception of Brooks Range orogeny, (6) exhumation and the end of main-stage deformation, and (7) subsequent episodic deformation. This compilation is supplemented by new 40Ar/39Ar dates of white mica from the Anarraaq and Red Dog Zn-Pb-Ag (+ barite) deposits from the western Brooks Range. The deposits are hosted in black shale and carbonate rocks of the Late Mississippian-Early Pennsylvanian Kuna Formation. Quartz-pyrite-white mica grains in sedimentary rocks above the Anarraaq deposit yield an age of 195.0 ?? 2.0 Ma, and paragenetically late quartz-pyrite-white mica from the Main orebody at the Red Dog deposit has an age of 126.1 ?? 0.7 Ma. These white micas are much younger than the age of Zn-Pb-Ag mineralization at Red Dog (338 ?? 5.8 Ma Re-Os age of pyrite). The date for white mica from Anarraaq (???195 Ma) appears to be related to a large-scale thermal event in the region immediately before the inception of the Brooks Range orogeny. The white mica from the Red Dog deposit (???126 Ma) correlates with the later stages of the orogeny, a period of blueschist metamorphism, extension, and rapid exhumation, which varied with geographic location. These dates suggest that the Red Dog deposits underwent significant hydrothermal overprinting during multiple episodes of the Brooks Range orogeny. ?? 2004 by Economic Geology.

  2. Magmatic and related mineral deposits of the Pan-African Saldania belt in the Western Cape Province, South Africa

    NASA Astrophysics Data System (ADS)

    Rozendaal, A.; Scheepers, R.

    1995-07-01

    Mineral deposits and prospects of the Pan-African Saldania orogenic belt in the Western Cape Province, South Africa, are reviewed. The polyphase, deformed, low-grade metamorphosed, volcano-sedimentary Malmesbury Group constitutes a complex, poorly understood supracrustal sequence that has been loosely subdivided into the Tygerberg, Swartland and Boland tectono-stratigraphic terranes on the basis of NW-trending fault zones. Syn- and post-tectonic granitoids of the Cape Granite Suite selectively intruded these terranes. Early S-types preferred the Tygerberg terrane, whereas the later I-types dominate the remaining areas. Anorogenic A-type granites, however, occur in all three terranes. Despite the absence of operating base or precious metal mines in the area, this study has established at least four metal associations directly or indirectly related to the intrusions: i) Cassiterite-wolframite (±Au, Cu, Mo, Zn, As, Fe-sulphides) in quartz and quartz/aplite veins hosted by tour-malinized and locally greissenized S-type granite. Similar exo-granitic veins occur in proximal metamorphites; ii) Juxtaposed, disseminated, stockwork breccia and vein style CuMoFe(Au)-sulphide mineralization hosted by mafic- to intermediate-intrusions of high-K calc-alkaline, I-type affinity; iii) CuMoAu-sulphides hosted by hydraulic breccia pipes, stocks and veins occurring in anorogenic A-type alkali feldspar granites and amphibole quartz syenites; iv) Scheelite with minor CuMoAu-sulphides associated with endo- and exo-skams spatially related to I-type monzogranite, granite and alkali feldspar granite. The first three associations occur along the Yzerfontein-Helderberg-zone, a 180 km lineament in the Tygerberg terrane, exploited by syn-, late- and post-tectonic intrusions and their related mineralization. The fourth association is typical of the Boland terrane. The spatial and temporal relationships among the various metal associations are interpreted as the result of

  3. Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China

    NASA Astrophysics Data System (ADS)

    Cao, MingJian; Qin, KeZhang; Li, GuangMing; Evans, Noreen J.; Jin, LuYing

    2014-09-01

    Methane is widely developed in hydrothermal fluids from reduced porphyry copper deposits, but its origin remains enigmatic. The occurrence of methane in fluid inclusions at the Late Carboniferous Baogutu reduced porphyry copper deposit in western Junggar, Xinjiang, NW-China, presents an excellent opportunity to address this problem. A systematic study including fluid inclusion Laser-Raman and CO2-CH4 carbon isotope analyses, igneous and hydrothermal mineral H-O isotope analyses, and in situ major, trace element and Sr isotopic analyses of hydrothermal epidote was conducted to constrain the origin of CH4 and CH4-rich fluids. The δ2H and δ18O of water in equilibrium with igneous biotite ranges from -65.0‰ to -66.0‰ and +7.2‰ to +7.4‰, respectively, indicating notable degassing of probably supercritical fluids in the magma chamber. The wide range of δ2H (-58.0‰ to -107.0‰, n = 23) for water within quartz suggests the existence of significant hydrothermal fluid boiling. Water-rock interaction is the most likely mechanism leading to the wide range of δ18O values for water in vein quartz with water/rock ratios (wt.% in O) of 0.15 to 0.75 and 0.13 to 0.46 for a closed and open system, respectively. Detailed Laser-Raman analyses indicate CO2 in apatite included in granodiorite porphyry phenocrystic biotite that records the carbon species of the early stage magmatic stage, whereas later hydrothermal fluids containing CH4 with trace or without CO2 are found in inclusions of vein quartz. We propose that CH4 is probably transformed from CO2 by Fischer-Tropsch type reactions at 500 °C, assumed from CO2-CH4 C isotope equilibrium. The (87Sr/86Sr)i of hydrothermal epidote yields values of 0.70369-0.70404, consistent with that reported for the whole rocks. The δ13CCH4 (-28.6‰ to -22.6‰) and δ2HCH4 (-108.0‰ to -59.5‰) are characteristic of abiogenic methane. The measured δ13CCO2 shows a slightly depleted 13C (-13.5‰ to -7.2‰) relative to upper mantle

  4. Structural controls on gold mineralization on the margin of the Yilgarn craton, Albany-Fraser orogen: The Tropicana deposit, Western Australia

    NASA Astrophysics Data System (ADS)

    Blenkinsop, Tom G.; Doyle, Mark G.

    2014-10-01

    The Tropicana gold deposit is located adjacent to the margin of the Yilgarn craton in the Albany-Fraser orogen, Western Australia. The deposit is hosted in granulite facies quartzo-feldspathic gneisses of the Archean Tropicana Gneiss. Ore bodies comprise biotite-pyrite alteration concentrated in shear zones that formed during NE-SW shortening in the late Archean, and clearly postdate the formation and deformation of high-grade gneiss fabrics (D1 and D2). The orientation of the ore bodies is controlled by the shear zones that are in turn localised by the gneissic banding. Mineralization also involved solution and coeval microfracturing and veining of more competent pegmatitic units. The mineralizing event (D3) was followed by at least two further deformations, which reactivated and overprinted the biotite fabrics with sericite and chlorite, created new shear zones, and affected gold distribution. D5 consisted of dextral shear on ∼E-W shear zones, which subdivide the deposit into five major structural domains. The importance of structurally controlled permeability at Tropicana is similar in cratonic lode gold deposits, as is the protracted deformation/fluid flow history. Like Renco mine in Zimbabwe, Tropicana gold deposit was formed by hydrothermal fluid flow peripheral to the craton: economic gold mineralization was clearly post-peak metamorphism.

  5. Oxidized and reduced mineral assemblages in greenstone belt rocks of the St. Ives gold camp, Western Australia: vectors to high-grade ore bodies in Archaean gold deposits?

    NASA Astrophysics Data System (ADS)

    Neumayr, Peter; Walshe, John; Hagemann, Steffen; Petersen, Klaus; Roache, Anthony; Frikken, Peter; Horn, Leo; Halley, Scott

    2008-03-01

    Hydrothermal sulfide-oxide-gold mineral assemblages in gold deposits in the Archaean St. Ives gold camp in Western Australia indicate extremely variable redox conditions during hydrothermal alteration and gold mineralization in space and time. Reduced alteration assemblages (pyrrhotite-pyrite) occur in deposits in the southwest of the camp (e.g., Argo, Junction deposits) and moderately to strongly oxidized assemblages (magnetite-pyrite, hematite-pyrite) occur in deposits in the Central Corridor in the northeast (e.g., North Orchin, Revenge deposits). Reduced mineral assemblages flank the Central Corridor of oxidized deposits and, locally, cut across it along E-W trending faults. Oxidized mineral assemblages in the Central Corridor are focused on gravity lows which are interpreted to reflect abundant felsic porphyritic intrusions at about 1,000 m below present surface. Hydrothermal magnetite predates and is synchronous with early phases of gold-associated albite-carbonate-pyrite-biotite-chlorite hydrothermal alteration. Later-stage, gold-associated pyrite is in equilibrium with hematite. The spatial distribution and temporal sequence of iron sulfides and oxides with gold indicate the presence of at least two spatially restricted but broadly synchronous hydrothermal fluids with contrasting redox states. Sulfur isotope constraints support the argument that the different mineral assemblages reflect differences in redox conditions. The δ 34S values for pyrite for the St. Ives gold camp range between -8.4‰ and +5.1‰ with the negative values occurring in oxidized magnetite-rich domains and slightly negative or positive values occurring in reduced, pyrrhotitic domains. Preliminary spatial and paragenetic analysis of the distribution of iron sulfides and oxides in the St. Ives camp suggests that gold grades are highest where the redox state of the hydrothermal alteration assemblages switches from relatively reduced pyrrhotite-pyrite to relatively oxidized magnetite

  6. Deposition of sedimentary organic matter in black shale facies indicated by the geochemistry and petrography of high-resolution samples, blake nose, western North Atlantic

    USGS Publications Warehouse

    Barker, C.E.; Pawlewicz, M.; Cobabe, E.A.

    2001-01-01

    A transect of three holes drilled across the Blake Nose, western North Atlantic Ocean, retrieved cores of black shale facies related to the Albian Oceanic Anoxic Events (OAE) lb and ld. Sedimentary organic matter (SOM) recovered from Ocean Drilling Program Hole 1049A from the eastern end of the transect showed that before black shale facies deposition organic matter preservation was a Type III-IV SOM. Petrography reveals that this SOM is composed mostly of degraded algal debris, amorphous SOM and a minor component of Type III-IV terrestrial SOM, mostly detroinertinite. When black shale facies deposition commenced, the geochemical character of the SOM changed from a relatively oxygen-rich Type III-IV to relatively hydrogen-rich Type II. Petrography, biomarker and organic carbon isotopic data indicate marine and terrestrial SOM sources that do not appear to change during the transition from light-grey calcareous ooze to the black shale facies. Black shale subfacies layers alternate from laminated to homogeneous. Some of the laminated and the poorly laminated to homogeneous layers are organic carbon and hydrogen rich as well, suggesting that at least two SOM depositional processes are influencing the black shale facies. The laminated beds reflect deposition in a low sedimentation rate (6m Ma-1) environment with SOM derived mostly from gravity settling from the overlying water into sometimes dysoxic bottom water. The source of this high hydrogen content SOM is problematic because before black shale deposition, the marine SOM supplied to the site is geochemically a Type III-IV. A clue to the source of the H-rich SOM may be the interlayering of relatively homogeneous ooze layers that have a widely variable SOM content and quality. These relatively thick, sometimes subtly graded, sediment layers are thought to be deposited from a Type II SOM-enriched sediment suspension generated by turbidities or direct turbidite deposition.

  7. Mercury deposition in snow near an industrial emission source in the western U.S. and comparison to ISC3 model predictions

    USGS Publications Warehouse

    Abbott, M.L.; Susong, D.D.; Krabbenhoft, D.P.; Rood, A.S.

    2002-01-01

    Mercury (total and methyl) was evaluated in snow samples collected near a major mercury emission source on the Idaho National Engineering and Environmental Laboratory (INEEL) in southeastern Idaho and 160 km downwind in Teton Range in western Wyoming. The sampling was done to assess near-field (<12 km) deposition rates around the source, compare them to those measured in a relatively remote, pristine downwind location, and to use the measurements to develop improved, site-specific model input parameters for precipitation scavenging coefficient and the fraction of Hg emissions deposited locally. Measured snow water concentrations (ng L-1) were converted to deposition (ug m-2) using the sample location snow water equivalent. The deposition was then compared to that predicted using the ISC3 air dispersion/deposition model which was run with a range of particle and vapor scavenging coefficient input values. Accepted model statistical performance measures (fractional bias and normalized mean square error) were calculated for the different modeling runs, and the best model performance was selected. Measured concentrations close to the source (average = 5.3 ng L-1) were about twice those measured in the Teton Range (average = 2.7 ng L-1) which were within the expected range of values for remote background areas. For most of the sampling locations, the ISC3 model predicted within a factor of two of the observed deposition. The best modeling performance was obtained using a scavenging coefficient value for 0.25 ??m diameter particulate and the assumption that all of the mercury is reactive Hg(II) and subject to local deposition. A 0.1 ??m particle assumption provided conservative overprediction of the data, while a vapor assumption resulted in highly variable predictions. Partitioning a fraction of the Hg emissions to elemental Hg(0) (a U.S. EPA default assumption for combustion facility risk assessments) would have underpredicted the observed fallout.

  8. Hydrothermal modification of host rock geochemistry within Mo-Cu porphyry deposits in the Galway Granite, western Ireland

    NASA Astrophysics Data System (ADS)

    Tolometti, Gavin; McCarthy, Will

    2016-04-01

    Hydrothermal alteration of host rock is a process inherent to the formation of porphyry deposits and the required geochemical modification of these rocks is regularly used to indicate proximity to an economic target. The study involves examining the changes in major, minor and trace elements to understand how the quartz vein structures have influenced the chemistry within the Murvey Granite that forms part of the 380-425Ma Galway Granite Complex in western Ireland. Molybdenite mineralisation within the Galway Granite Complex occurred in close association with protracted magmatism at 423Ma, 410Ma, 407Ma, 397Ma and 383Ma and this continues to be of interest to active exploration. The aim of the project is to characterize hydrothermal alteration associated with Mo-Cu mineralisation and identify geochemical indicators that can guide future exploration work. The Murvey Granite intrudes metagabbros and gneiss that form part of the Connemara Metamorphic complex. The intrusion is composed of albite-rich pink granite, garnetiferous granite and phenocrytic orthoclase granite. Minor doleritic dykes post-date the Murvey Granite, found commonly along its margins. Field mapping shows that the granite is truncated to the east by a regional NW-SE fault and that several small subparallel structures host Mo-Cu bearing quartz veins. Petrographic observations show heavily sericitized feldspars and plagioclase and biotite which have undergone kaolinization and chloritisation. Chalcopyrite minerals are fine grained, heavily fractured found crystallized along the margins of the feldspars and 2mm pyrite crystals. Molybdenite are also seen along the margins of the feldspars, crystallized whilst the Murvey Granite cooled. Field and petrographic observations indicate that mineralisation is structurally controlled by NW-SE faults from the selected mineralization zones and conjugate NE-SW cross cutting the Murvey Granite. Both fault orientations exhibit quartz and disseminated molybdenite

  9. Geochemistry of the Yangla volcanic rocks and its relationship to Cu mineralization in the Yangla copper deposit, western Yunnan, China

    NASA Astrophysics Data System (ADS)

    Yang, Xian; Liu, Jiajun; Zhai, Degao; Han, Siyu; Wang, Huan; Yang, Longbo; Huo, Dongliang

    2012-10-01

    The Yangla copper deposit is a recently discovered, giant copper deposit with an estimated Cu reserve of about 1,200,000 tons. Development is now underway. Previous studies have reported that the Yangla copper deposit is a VMS-type deposit related to the Yangla volcanic rocks. Volcanic bulk-rock analyses shows high contents of Si (49.3%-58.7%), Na2O (Na2O = 3.3%-4.9%), MgO (MgO = 3.7%-8.6%), and CaO(CaO = 6.8%-9.0%), low TiO2 (TiO2 = 0.9%-2.1%) and K2O(K2O = 0.2%-1.4%) contents. The geochemistry of the volcanic represent forearc basalts. Four molybdenites samples from the ore bodies in the deposit yield Re-Os model ages ranging from 229.7 ± 3.3 Ma to 233 ± 3.4 Ma. The REE distribution patterns and the primitive-mantle-normalized trace element patterns of the volcanic rocks are similar to the ores, indicating the Yangla copper deposit are closely associated with the Yangla volcanic rocks. The results contribute to our understanding of the genesis of the Yangla copper deposit and will guide further exploration in the region.

  10. Application of geologic-mathematical 3D modeling for complex structure deposits by the example of Lower- Cretaceous period depositions in Western Ust - Balykh oil field (Khanty-Mansiysk Autonomous District)

    NASA Astrophysics Data System (ADS)

    Perevertailo, T.; Nedolivko, N.; Prisyazhnyuk, O.; Dolgaya, T.

    2015-11-01

    The complex structure of the Lower-Cretaceous formation by the example of the reservoir BC101 in Western Ust - Balykh Oil Field (Khanty-Mansiysk Autonomous District) has been studied. Reservoir range relationships have been identified. 3D geologic- mathematical modeling technique considering the heterogeneity and variability of a natural reservoir structure has been suggested. To improve the deposit geological structure integrity methods of mathematical statistics were applied, which, in its turn, made it possible to obtain equal probability models with similar input data and to consider the formation conditions of reservoir rocks and cap rocks.

  11. Comparison of mercury mass loading in streams to atmospheric deposition in watersheds of Western North America: Evidence for non-atmospheric mercury sources.

    PubMed

    Domagalski, Joseph; Majewski, Michael S; Alpers, Charles N; Eckley, Chris S; Eagles-Smith, Collin A; Schenk, Liam; Wherry, Susan

    2016-10-15

    Annual stream loads of mercury (Hg) and inputs of wet and dry atmospheric Hg deposition to the landscape were investigated in watersheds of the Western United States and the Canadian-Alaskan Arctic. Mercury concentration and discharge data from flow gauging stations were used to compute annual mass loads with regression models. Measured wet and modeled dry deposition were compared to annual stream loads to compute ratios of Hg stream load to total Hg atmospheric deposition. Watershed land uses or cover included mining, undeveloped, urbanized, and mixed. Of 27 watersheds that were investigated, 15 had some degree of mining, either of Hg or precious metals (gold or silver), where Hg was used in the amalgamation process. Stream loads in excess of annual Hg atmospheric deposition (ratio>1) were observed in watersheds containing Hg mines and in relatively small and medium-sized watersheds with gold or silver mines, however, larger watersheds containing gold or silver mines, some of which also contain large dams that trap sediment, were sometimes associated with lower load ratios (<0.2). In the non-Arctic regions, watersheds with natural vegetation tended to have low ratios of stream load to Hg deposition (<0.1), whereas urbanized areas had higher ratios (0.34-1.0) because of impervious surfaces. This indicated that, in ecosystems with natural vegetation, Hg is retained in the soil and may be transported subsequently to streams as a result of erosion or in association with dissolved organic carbon. Arctic watersheds (Mackenzie and Yukon Rivers) had a relatively elevated ratio of stream load to atmospheric deposition (0.27 and 0.74), possibly because of melting glaciers or permafrost releasing previously stored Hg to the streams. Overall, our research highlights the important role of watershed characteristics in determining whether a landscape is a net source of Hg or a net sink of atmospheric Hg. PMID:27015962

  12. Source versus depositional controls on sandstone composition in a foreland basin: The El Imperial Formation (Mid Carboniferous-Lower Permian), San Rafael basin, western Argentina

    SciTech Connect

    Espejo, E.S. ); Lopez-Gamundi, O.R. . Frontier Exploration Dept.)

    1994-01-01

    The El Imperial Formation (mid-Carboniferous-Lower Permian) constitutes a progradational sandstone-rich succession deposited in the San Rafael foreland basin of western Argentina. Four facies associations have been identified: a basal glacial marine association, a shallow marine association, a deltaic association, and an uppermost fluvial association. Sand-prone deposits in the deltaic association, a shallow marine association, a deltaic association, and an uppermost fluvial association. Sand-prone deposits in the deltaic association are represented by prodelta and delta-front shales and subordinate fine sandstones (Facies A), deltaic platform, wave-reworked channel mouth-bar sandstones (Facies B), and fluvial-dominated distributary channel sandstones (Facies C). Analysis of framework grains of sandstone samples from Facies B and C shows two distinct mineral assemblages or petrofacies. The quartzose petrofacies is characterized by high contents of quartz and low percentages of feldspar and lithic grains. The quartzolithic petrofacies shows an increase in labile components, in particular lithic fragments, and a concomitant decrease in quartz. The quartzolithic petrofacies shows a source signature. Average detrital modes of sandstones from this petrofacies are similar to those from overlying fluvial sandstones. All wave-reworked, channel mouth-bar sandstones (Facies B) correspond compositionally to the quartzose petrofacies, whereas detrital modes from the distributary-channel sandstones (Facies C) fall into the quartzolithic petrofacies. This correspondence between depositional environment and petrofacies suggests a strong depositional influence on composition (depositional signature). Abrasion (mechanical breakdown) by wave action in shallow marine environments accounts for the quartz-rich nature and paucity of labile grains in the quartzose petrofacies.

  13. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in Western US National Park fish: Concentrations and consumption guidelines

    EPA Science Inventory

    Concentrations of polybrominated diphenyl ethers (PBDEs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons were measured in 136 fish from 14 remote lakes in 8 western U.S. National Parks/Preserves between 2003 and 2005 and compared to human and w...

  14. The Paleozoic Dust Bowl: Dust Deposition in Tropical Western Pangaea (Midcontinent U.S.) at the Terminus of the Late Paleozoic Ice Age

    NASA Astrophysics Data System (ADS)

    Soreghan, G. S.; Heavens, N. G.; Benison, K. C.; Soreghan, M. J.; Mahowald, N. M.; Foster, T.; Zambito, J.; Sweet, A.; Kane, M.

    2012-12-01

    Atmospheric dust is well recognized and studied as both an archive and agent of climate change in Earth's relatively recent past. Archives of past dust include loess deposits and dust recovered from ocean- and ice-cores. Dust remains poorly known in Earth's past prior to the Cenozoic, but is increasingly recognized in the form of paleo-loess deposits, and (epeiric) marine strata that accumulated isolated from fluvio-deltaic influx. Here, we report on the growing recognition of voluminous dust deposits preserved in the Permian record of the U.S. Midcontinent (western tropical Pangaea). Fine-grained redbeds predominate in Permian strata throughout the U.S. Midcontinent, but notably in a swath extending from Oklahoma through South Dakota. These units consist predominantly of red mudstone and siltstone in commonly massive units, but sedimentary structures and bedding that signal aqueous processes (e.g. laminations, ripples) have led most to infer deltaic or tidal deposition. The absence of channel systems to deliver the sediment, as well as the predominantly massive and laterally continuous character and the uniform fine grain size signal wind transport, implying that these units record sustained dust deposition overprinted at times by sub-aqueous deposition in lakes, including ephemeral saline and acid lakes that led to evaporite cementation. Detrital zircon geochronology indicates that much of the dust originated in the relatively distant Appalachian-Ouachita orogenic systems, which formed part of the central Pangaean mountains (CPM), the collisional zone that sutured the supercontinent. Within the Anadarko basin of Oklahoma, Permian redbeds record >2 km of predominantly dust deposition, some of the thickest dust deposits yet documented in Earth's record. Yet the tropical setting is remarkably non-uniformitarian, as much Quaternary loess occurs in mid- to high-latitude regions, commonly linked to glacial genesis. We are currently investigating with both data and

  15. Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia

    USGS Publications Warehouse

    Brown, S.M.; Johnson, C.A.; Watling, R.J.; Premo, W.R.

    2003-01-01

    The Cleo gold deposit, 55 km south of Laverton in the Eastern Goldfields Province of Western Australia, is characterised by banded iron-formation (BIF)-hosted ore zones in the gently dipping Sunrise Shear Zone and high-grade vein-hosted ore in the Western Lodes. There is evidence that gold mineralisation in the Western Lodes (which occurred at ca 2655 Ma) post-dates the majority of displacement along the Sunrise Shear Zone, but it remains uncertain if the ore in both structures formed simultaneously or separately. Overall, the Pb, Nd, Sr, C. O and S isotopic compositions of ore-related minerals from both the Western Lodes and ore zones in the Sunrise Shear Zone are similar. Early low-salinity aqueous-carbonic fluids and late high-salinity fluids with similar characteristics are trapped in inclusions in quartz veins from both the Sunrise Shear Zone and the Western Lodes. The early CO2, CO2-H2O, and H2O- dominant inclusions are interpreted as being related to ore formation, and to have formed from a single low-salinity aqueous-carbonic fluid as a result of intermittent fluid immiscibility. Homogenisation temperatures indicate that these inclusions were trapped at approximately 280??C and at approximately 4 km depth, in the deeper epizonal range. Differences between the ore zones are detected in the trace-element composition of gold samples, with gold from the Sunrise Shear Zone enriched in Ni, Pb, Sn, Te and Zn, and depleted In As, Bi, Cd, Cu and Sb, relative to gold from the Western Lodes. Although there are differences in gold composition between the Sunrise Shear Zone and Western Lodes, and hence the metal content of ore fluids may have varied slightly between the different ore zones, no other systematic fluid or solute differences are detected between the ore zones. Given the fact that the ore fluids in each zone have very similar bulk properties, the considerable differences in gold grade, sulfide mineral abundance, and ore textures between the two ore zones

  16. Gold mineralisation at the Lady Bountiful Mine, Western Australia: An example of a granitoid-hosted Archaean lode gold deposit

    NASA Astrophysics Data System (ADS)

    Cassidy, K. F.; Bennett, J. M.

    1993-12-01

    The Lady Bountiful granitoid-hosted lode gold deposit, located in the mid-greenschist facies metamorphosed Ora Banda greenstone sequence, is hosted predominantly by the late-tectonic Liberty Granodiorite. Gold mineralisation is localised along quartz-veined, sinistral, brittle fault-zone(s) that transect the boundary between the Liberty Granodiorite and Mt Pleasant sill. Quartz vein textures indicate two stages of a single gold-related vein-development event, with high-grade gold mineralisation restricted to the second stage. Ore minerals include pyrite, chalcopyrite, pyrrhotite, galena, sphalerite, Au-Ag-Bi-Pb-tellurides, and native gold. Fluid infitration has resulted in narrow (<1 m) bleached wallrock alteration envelopes to the fault zones comprising albite-K-mica ±chlorite±calcite±rutile assemblages. Temperature-pressure conditions varied from Stage I (300°±50°C, ≈2 kbar) to Stage II (250°±50°C, ≈0.5 to 2 kbar), with the hydrothermal fluid in both stages characterised by X(CO2)≤0.15 and moderate salinity (≈1.28 m NaCl). Intermittent phase separation of Stage II mineralising fluids, initiated by pressure fluctuations in dilational sites, and/or fluid-dominated fluid: wallrock interaction, are invoked as the dominant depositional mechanisms. The granitoid-hosted Lady Bountiful lode gold deposit shares many features with other granitoid-hosted lode gold deposits in the Yilgarn Craton and the Superior Province. Granitoid-hosted lode gold deposits, such as the Lady Bountiful deposit, provide additional evidence that the dominant control on the localisation of gold mineralisation within a granitoid host is structure, with competency contrasts playing a significant role. Furthermore, the hydrothermal wallrock alteraction and orefluid chemistry characteristics of the granitoid-hosted lode gold deposits are comparable to those established for greenstone-hosted lode gold mineralisation.

  17. Reconstruction of Holocene coastal depositional environments based on sedimentological and palaeontological analyses, Zakynthos Island, Western Greece Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Avramidis, Pavlos; Iliopoulos, George; Papadopoulou, Penelope; Nikolaou, Konstantinos; Kontopoulos, Nikolaos; Wijngaarden, Gert

    2014-05-01

    Zakynthos Island is one of the most seismically active regions in Europe and the Holocene coastal depositional environments were influenced both by tectonic activity and sea level rise. In the present study detailed sedimentological, palaeontological and 14C dating analyses were used in order to reconstruct the Holocene coastal depositional environments as well as the different rates of sedimentation, based on data from three cores up to 30 m deep. The results of the analyses indicate changes in depositional environments from marine to brackish lagoonal and lagoon / barrier systems with temporary intrusions of marine water via storms or tsunamigenic events. High sedimentation rates in coastal areas of Zakynthos Island correspond well to the most widespread Holocene warm and humid phases. The interpretation of the sedimentological environments reveals that Zakynthos Island before 8300 BP was constituted by two islands, where the present southern part of the island was separated from the northern one by a shallow and narrow sea channel.

  18. Characteristics and genesis of mineral deposits in East Ujimqin Banner, western segment of the Great Xing'an Mountains, NE China

    NASA Astrophysics Data System (ADS)

    Zhang, Wanyi; Nie, Fengjun; Liu, Shuwen; Zuo, Liyan; Yao, Xiaofeng; Jia, Delong; Liu, Jiangtao

    2015-01-01

    The East Ujimqin Banner, located in the western segment of the Great Xing'an Mountains, NE China, has undergone a long and multi-stage tectonic evolution, which has resulted in significant Fe-Ag-Pb-Zn-Au-Cu-Mo deposits. There are two main types of mineralization: vein and skarn types. The Jilinbaolige and Aerhada vein deposits, and the Chagan Obo and Chaobuleng skarn-type deposits are four typical deposits in this area. The vein deposits mainly occur as veins with hydrothermal alteration in fractures within pre-mineralization clastic rocks and felsic volcanic rocks. The skarn-type deposits always show a temporal and spatial relationship with Mesozoic granite intruded into Paleozoic limestone. The sulfur isotope data from the sulfides in these four deposits have a very narrow range (+1‰ to +8‰), suggesting that most were derived from magma. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios range from 17.949 to 18.529, 15.370 to 15.691 and 37.653 to 38.460 respectively, indicating that the metals derive mainly from the mantle source. In the diagrams 207Pb/204Pb vs. 206Pb/204Pb and 208Pb/204Pb vs. 206Pb/204Pb, the points of lead isotope of the sulfide ores are very near or coincide to the K-feldspar, indicating that the ore-forming materials sources have the genetic relationship. It seems that there are four key factors controlling the mineralization styles in this district: the tectonic setting, magmatic activity, wall rocks, and structures. The superposition of multi-stage tectonism from a Mesozoic extensional setting on a Paleozoic subduction setting provided a remobilization and enrichment mechanism for the ore-forming elements. The magmatic activities were sources of metals and fluids, and drove them to the mineralization sites. The wall rocks are key factors for mineralization styles. When metal-bearing fluid flows into clastic rocks and felsic volcanic rocks, the mineralization is mainly vein type, and mineralization in limestone is mainly skarn type. NE

  19. The largest Au deposits in the St Ives Goldfield (Yilgarn Craton, Western Australia) may be located in a major Neoarchean volcano-sedimentary depo-centre

    NASA Astrophysics Data System (ADS)

    McGoldrick, K. L.; Squire, R. J.; Cas, R. A. F.; Briggs, M.; Tunjic, J.; Allen, C. M.; Campbell, I. H.; Hayman, P. C.

    2013-10-01

    The largest Neoarchean gold deposits in the world-class St Ives Goldfield, Western Australia, occur in an area known as the Argo-Junction region (e.g. Junction, Argo and Athena). Why this region is so well endowed with large deposits compared with other parts of the St Ives Goldfield is currently unclear, because gold deposits at St Ives are hosted by a variety of lithologic units and were formed during at least three different deformational events. This paper presents an investigation into the stratigraphic architecture and evolution of the Argo-Junction region to assess its implications for gold metallogenesis. The results show that the region's stratigraphy may be subdivided into five regionally correlatable packages: mafic lavas of the Paringa Basalt; contemporaneously resedimented feldspar-rich pyroclastic debris of the Early Black Flag Group; coarse polymictic volcanic debris of the Late Black Flag Group; thick piles of mafic lavas and sub-volcanic sills of the Athena Basalt and Condenser Dolerite; and the voluminous quartz-rich sedimentary successions of the Early Merougil Group. In the Argo-Junction region, these units have an interpreted maximum thickness of at least 7,130 m, and thus represent an unusually thick accumulation of the Neoarchean volcano-sedimentary successions. It is postulated that major basin-forming structures that were active during deposition and emplacement of the voluminous successions later acted as important conduits during mineralisation. Therefore, a correlation exists between the location of the largest gold deposits in the St Ives Goldfield and the thickest parts of the stratigraphy. Recognition of this association has important implications for camp-scale exploration.

  20. Breastfeeding practices in Chengdu, Sichuan, China.

    PubMed

    Guldan, G S; Zhang, M; Zeng, G; Hong, J; Yang, Y

    1995-03-01

    Barriers to increased breastfeeding rates in Chengdu, Sichuan were investigated in 1992 and 1993. Responses of focus groups showed that ignorance about breastfeeding and belief that the mother's milk was inadequate, and lack of support from their families, places of employment, and the health system acted as barriers to the women's breastfeeding their infants up to the age of four to six months. Subsequently, 363 mothers of 4- to 12-month-old Chengdu infants were surveyed. Although most mothers in both studies said breastmilk was the best food for their infant up to age of four to six months, only about half of the mothers breastfed for longer than one month. Both studies showed that infants who roomed with their mothers after birth were more likely to have been put to their mother's breast earlier, fed colostrum, breastfed somewhat longer, and exclusively breastfed for a somewhat longer period, although their mothers' infant feeding knowledge did not differ. The researchers conclude that Chengdu health workers should teach parents and parents-to-be more about breastfeeding, and that rooming-in be expanded in Chengdu hospitals. PMID:7718100

  1. Paleozoic sedimentary rocks in the Red Dog Zn-Pb-Ag district and vicinity, western Brooks Range, Alaska: provenance, deposition, and metallogenic significance

    USGS Publications Warehouse

    Slack, John F.; Dumoulin, Julie A.; Schmidt, J.M.; Young, L.E.; Rombach, Cameron

    2004-01-01

    The distribution and composition of Paleozoic strata in the western Brooks Range may have played a fundamental role in Zn-Pb mineralization of the Red Dog district. In our model, deposition and early lithification of biogenic chert and bedded siliceous rocks in the upper part of the Kuna Formation served as a regional hydrologic seal, acting as a cap rock to heat and hydrothermal fluids during Late Mississippian base-metal mineralization. Equally important was the iron-poor composition of black shales of the Kuna Formation (i.e., low Fe/Ti ratios), which limited synsedimentary pyrite formation in precursor sediments, resulting in significant H2S production in pore waters through the interaction of aqueous sulfate with abundant organic matter. This H2S may have been critical to the subsurface deposition of the huge quantities of Zn and Pb in the district. On the basis of this model, we propose that low Fe/Ti and S/C ratios in black shale sequences are potential basin-scale exploration guides for giant sediment-hosted, stratiform Zn-Pb-Ag deposits.

  2. Geophysical Exploration of Disseminated and Stockwork deposits associated with plutonic intrusive: A Case study in the eastern flank of the western Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Hernandez, O.; Alexander, G. C.; Pintor, I. M.

    2011-12-01

    Disseminated deposit exploration in the tropics suffers from difficult geological mapping due to thick vegetation, lack of rock outcrop, and extensive but variable saprolitic weathering. Geophysical exploration of these deposits normally includes magnetic, induced polarization and gamma ray spectrometry surveys. The largest RTP Total field magnetic anomaly highs are usually associated with the diorite porphyry intrusive bodies. Normally, diorites are less magnetic than the basaltic rocks. Therefore, where the magnetic anomaly highs are related to the intrusions they can be explained by the intensive mineralization of basic metals including magnetite that are associated with the porphyry intrusions. Regularly, the magnetic anomaly gradients help to delineate local discontinuities that can be interpreted as local faults and joints that can be mineralized. The gamma ray spectrometry is useful to determine the anomalous concentration of Potassium, Uranium and Thorium that can be interpreted in terms of alteration halos and linear discontinuities. The statistical analysis of the data also can determine the intermediate intrusive / extrusive nature of the porphyry intrusions. The use of gamma ray spectrometry helps to determine the concentration of elemental potassium, regardless of the associated potassium mineral species, enabling alteration mapping in a geological setting related to volcanic-associated massive sulphide base metals and gold. The induced polarization survey is useful in outlining sulphide distribution in porphyry deposits related to chargeability anomaly highs. The preliminary results of the geophysical exploration program of the eastern flank of the Western Cordillera in the Andes Mountains of Colombia are discussed.

  3. Field and ASTER imagery data for the setting of gold mineralization in Western Allaqi-Heiani belt, Egypt: A case study from the Haimur deposit

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem; Emam, Ashraf

    2014-11-01

    Although associated with carbonatized/listvenitized ophiolites and thrust structures, the morphology and internal structures of the auriferous quartz veins in the Haimur deposit suggest mineralization concurrent with NE-SW dextral brittle-ductile shear zones. The latter are attributed to intense transpression regime and are associated with (N)NE-trending tight to isoclinals folds that deform the early accretionary structures. Image processing techniques applicable to the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data are used for mapping structures and hydrothermal alteration associated with the Haimur deposit. The automated lineament extraction by LINE module on high resolution ASTER imagery provides efficient data for potential dilation loci. Emphasis is placed on reliability of mineral indices extracted from the ASTER band ratios for identification of possibly mineralized alteration zones associated with NE-trending shear zones. Field and remote sensing data, together with the structural fabrics along the lode-associated shear zones clearly constrain on the genetic relationship between the Haimur gold deposit and post-accretionary transpression/shearing. We conclude that hydrothermal alteration zones that are confined to tightly enfolded ophiolites and transpressive shear zones along the Western Allaqi-Heiani belt are most potential targets for new exploration plans.

  4. Geological, mineralogical and geochemical characteristics of zeolite deposits associated with borates in the Bigadiç, Emet and Kirka Neogene lacustrine basins, western Turkey

    NASA Astrophysics Data System (ADS)

    Gündogdu, M. N.; Yalçin, H.; Temel, A.; Clauer, N.

    1996-09-01

    The Bigadiç, Emet and Kirka lacustrine basins of western Turkey may be considered as Tibet-type graben structures that were developed during the Miocene within the Izmir-Ankara suture zone complex. The volcanic-sedimentary successions of these basins are made up of mudstone, carbonate (limestone and dolomite) and detrital rocks, and also of crystal or vitric tuffs about 135 to 200 m thick. The Degirmenli (Bigadiç), Emirler (Bigadiç) Köpenez (Emet) and Karaören (Kirka) tuffs constituting the zeolite deposits are situated beneath four borate deposits (colemanite, ulexite, borax). The most abundant diagenetic silicate minerals are K- and Ca-clinoptilolites in the zeolite deposits, and Li-rich trioctahedral smectites (stevensite, saponite and hectorite) and K-feldspar in the borate deposits. In the Degirmenli, Emirler, Köpenez and Karaören deposits, the following diagenetic facies were developed from rhyolitic glasses rich in K and poor in Na: (glass+smectite), (K-clinoptilolite+opal-CT), (Ca-clinoptilolite+K-feldspar±analcime± quartz) and (K-feldspar+analcime+quartz). K-feldspar which is also rarely associated with phillipsite (Karaören) and heulandite (Degirmenli and Karaören), succeeds clinoptilolite and precedes analcime in these diagenetic facies where dioctahedral smectites, opal-CT and quartz are the latest minerals. No diagenetic transformations exist between clinoptilolite, K-feldspar and analcime that were formed directly from glass. The lateral facies distributions resulted from the differences in salinity and pH of pore water trapped during deposition of the tuffs, but vertical distributions in vitric tuffs seem to have been controlled by the glass/liquid ratio of the reacting system and the permeability or diffusion rate of alkali elements. The Bigadiç, Emet and Kirka zeolite deposits which were formed in saline basins rich in Ca and Mg ions, show similar chemical changes, i.e. loss of alkalis and gain in alkaline-earth elements that have taken

  5. Uranium-series ages of corals and coexisting phosphate deposits on Pelsaert Reef Complex, Houtman-Abrolhos Islands, Western Australia

    NASA Astrophysics Data System (ADS)

    Veeh, H. Herbert; France, Roy E.

    1988-09-01

    An unusually well-defined association between guano-derived phosphate rock (apatite) and coral carbonates on Pelsaert Island has provided an opportunity to test uranium-series dating methods as applied to insular phosphorites. The phosphate deposit, which is bracketed by late Pleistocene and Holocene corals with {230Th}/{234U} ages of 120,000 and 4700 yr B.P., respectively, has {230Th}/{234U} ages ranging from 85,000 to 112,000 yr B.P. The mutually consistent results suggest that phosphate deposition commenced soon after the peak of the last interglaciation and has been largely controlled by sea-level fluctuations and probably other factors associated with late Quaternary climate in this area.

  6. Stratigraphy, sedimentology, paleontology, and paleomagnetism of Pliocene-early Pleistocene lacustrine deposits in two cores from western Utah

    USGS Publications Warehouse

    Thompson, R.S.; Oviatt, Charles G.; Roberts, A.P.; Buchner, J.; Kelsey, R.; Bracht, C.J.; Forester, R.M.; Bradbury, J.P.

    1995-01-01

    The paleoclimatic history of western Utah is being investigated as part of the USGS Global Change and Climate History Program studies of long-term climatic changes in the western United States. The initial objective of the study is to document the environmental conditions during the mid-Pliocene period of warmer-than-modern global climates (the focus of the USGS Pliocene Research, Interpretation, and Synoptic Mapping [PRISM] project). The investigation also seeks to determine how and when these conditions gave way to the late Quaternary pattern of climatic variations (in which short periods of very moist climates have been separated by long periods of arid conditions). This is a collaborative project involving specialists from the USGS, Kansas State University, and the University of California-Davis in paleontology (Thompson, Buchner, Forester, Bradbury), stratigraphy and sedimentology (Oviatt, Kelsey, Bracht), and paleomagnetism and environmental magnetism (Roberts). The data presented herein represent preliminary findings of the analyses of two cores of Pliocene and early Pleistocene sediments from the eastern Great Basin.

  7. Ca/Mg ratio and depositional cycles in marine upper Absheron substage succession in the Western flank of the South Caspian depression

    NASA Astrophysics Data System (ADS)

    Amirov, E.

    2009-04-01

    The Caspian Sea, the largest land locked basin in the world, isolated from ParaTethys at the end of Messinian. Since that time sedimentation there took place under conditions of isolated basin temporarily connected with Black Sea in Upper Pliocene (Akchagyl). The aim of this work was the reconstruction of paleotemperature of South Caspian basin in marine upper Absheron substage time by using Ca/Mg ratio from ostracoda carapaces. The results of the field works on exposures of the Lower Pleistocene deposits located in the Western flank of the South Caspian depression (Shikhov outcrop) demonstrated the high-frequency cyclicity in sedimentation accompanied by rapid lateral and vertical depositional environmental change. It is possible to observe several depositional sequences developed from low stand system tract to transgressive and high stand system tract. The quantitative changes of ostracoda composition for each interbed depending on paleotemperature fluctuations, in detail point out the tendency of increasing and decreasing of Ca/Mg ratio in carapaces as indicator of paleotemperature. It was clearly recognized that Ca/Mg ratio increases in high stand system tract and decreases in regressive systems tracts. As well as was observed positive correlation tendency between amount of ostracoda carapaces and Ca/Mg ratio, in most cases with increasing of Ca/Mg ratio, amount of ostarcoda carapaces increase and with decreasing of Ca/Mg ratio, amount of ostracoda carapaces decrease. Just in some cases we can observe invert correlation. Carried out biogeochemical analyses have shown that amount of the studied elements, including Ca and Mg considerably varies in a section, which reflects the change in paleotemperature and depositional setting during accumulation of sediments.

  8. SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis

    USGS Publications Warehouse

    Aleinikoff, John N.; Hayes, Timothy S.; Evans, Karl V.; Mazdab, Frank K.; Pillers, Renee M.; Fanning, C. Mark

    2012-01-01

    Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones. Xenotime overgrowths (1–30 μm wide) were found in polished thin sections from five ore and near-ore zones (chalcocite-chlorite, bornite-calcite, galena-calcite, chalcopyrite-ankerite, and pyrite-calcite), but not in more distant zones across the region. Thirty-two in situ SHRIMP U-Pb analyses on xenotime overgrowths yield a weighted average of 207Pb/206Pb ages of 1409 ± 8 Ma, interpreted as the time of mineralization. This age is about 40 to 60 m.y. after deposition of the Revett Formation. Six other xenotime overgrowths formed during a younger event at 1304 ± 19 Ma. Several isolated grains of xenotime have 207Pb/206Pb ages in the range of 1.67 to 1.51 Ga, and thus are considered detrital in origin. Trace element data can distinguish Spar Lake xenotimes of different origins. Based on in situ SHRIMP analysis, detrital xenotime has heavy rare earth elements-enriched patterns similar to those of igneous xenotime, whereas xenotime overgrowths of inferred hydrothermal origin have hump-shaped (i.e., middle rare earth elements-enriched) patterns. The two ages of hydrothermal xenotime can be distinguished by slightly different rare earth elements patterns. In addition, 1409 Ma xenotime overgrowths have higher Eu and Gd contents than the 1304 Ma overgrowths. Most xenotime overgrowths from the Spar Lake deposit have elevated As concentrations, further suggesting a genetic relationship between the xenotime formation and Cu-Ag mineralization.

  9. Spatial correlation of mantle heterogeneities beneath the south-western part of the East-European platform with oil-gas deposits and basic-ultrabasic magmatism.

    NASA Astrophysics Data System (ADS)

    Shumlyanska, L.

    2009-04-01

    Velocity model of mantle beneath the south-western margin of the East-European platform demonstrates its heterogeneous structure. Accordingly to the crustal structures above mantle heterogeneities were defined as: Volyno-Podolian, Ros-Bug, Ingulo-Middlednieper, Periasov, Volyno-Podolian plate, Peridnister, Peri-Blacksea, Chernigov, Dnieper, Donetsk, Eastern-Blacksea, Crimea, Western-Blacksea. These blocks are defined as regions differing in the depth of the bottom of the velocity layers that characterize velocity structure of the mantle and in the velocity characteristics of these layers. Layer boundaries are defined as intersection with 1-d reference model. Areas with residuals >0.0 km/s are considered as high-velocity while areas with residuals <0.0 km/s are defined as low-velocity. There is a spatial correlation between boundaries of mantle blocks and location of oil-gas deposits and basic-ultrabasic magmatism. Some of the mantle blocks (Peri-Blacksea, Eastern-Blacksea, Crimea, Western-Blacksea, Periasov, Volyno-Podolian plate, Peridnister) that situated beneath margin of the platform and others (Chernigov, Dnieper, Donetsk) that situated beneath the Dnieper-Donetsk depression display spatial correlation with crust-seated oil-gas provinces - Crimean, Volyno-Podolian, Pericarpathian, and Dnieper-Donetsk, correspondingly. Oil-gas field have a propensity for boundaries of mentioned above mantle blocks. Those mantle blocks (Volyno-Podolian, Ros-Bug, Ingulo-Middlednieper, Periasov) that located under the Ukrainian shield display spatial correlation with basic-ultrabasic magmatism that confined to the blocks boundaries. Age of this magmatism varies from Paleoproterozoic to Neoproterozoic. Velocity model of the south-western part of the East-European platform obtained by the method of seismic tomography employing methodology of the Taylor's approximation of the solution of the task of seismic tomography of the times of arrivals of P-waves developed by V.S. Geyko [1

  10. Imprint of North-Atlantic abrupt climate changes on western European loess deposits as viewed in a dust emission model

    NASA Astrophysics Data System (ADS)

    Sima, Adriana; Rousseau, Denis-Didier; Kageyama, Masa; Ramstein, Gilles; Schulz, Michael; Balkanski, Yves; Antoine, Pierre; Dulac, François; Hatté, Christine

    2009-12-01

    Western European loess sequences of the last glaciation (˜100,000-15,000 years BP) exhibit strong, cyclic variations of the sedimentation rate, which are coeval to the Greenland stadial/interstadial cycles and the Heinrich events. These North-Atlantic rapid climate changes appear, thus, as a potential cause for the sedimentation variations, via changes in dust intensity cycle. Here we make a first step in testing this hypothesis, by modelling the impact of the North-Atlantic abrupt climate variations on dust emission. Our dust emission calculations use meteorological fields generated by the LMDZ atmospheric general circulation model at a resolution down to 60 km over Western Europe. Three numerical experiments are run, representing a Greenland stadial, an interstadial and a Heinrich event. Orbital parameters and ice-sheet configuration correspond to conditions from Marine Isotope Stage 3 (˜60,000-25,000 years BP), a period characterized by strong millennial-scale climate variability. The only differences we impose in the boundary conditions regard the North-Atlantic surface temperature and sea-ice cover in the latitudinal band 30°-63°N. The changes in wind, precipitation, soil moisture and snow cover from one simulated state to another result in small differences in dust emission intensity. In contrast, when the inhibition of the aeolian erosion by vegetation is taken into account, the dust fluxes for the cold climate states (Greenland stadial and Heinrich event) become generally more than twice higher than those for the relatively warmer Greenland interstadial, in agreement with the loess data. These results support the hypothesis that the North-Atlantic millennial-scale variability is imprinted in Western European loess profiles, and point to vegetation changes as the main factor responsible for millennial-scale sedimentation variations. An analysis for the English Channel and southern North Sea areas, major potential dust sources, shows that the seasonality

  11. Hydrothermal alteration, ore fluid characteristics, and gold depositional processes along a trondhjemite-komatiite contact at Tarmoola, Western Australia

    USGS Publications Warehouse

    Duuring, P.; Hagemann, S.G.; Cassidy, K.F.; Johnson, C.A.

    2004-01-01

    Tarmoola is a structurally controlled Archean orogenic gold deposit hosted in greenschist facies metamorphosed komatiite and trondhjemite in the Leonora district of the Eastern Goldfields province, Yilgarn craton. High-grade (>1 g/t Au) orebodies are located in komatiite wall rock adjacent to the eastern and northeastern margins of the asymmetrical, north-south-striking, Tarmoola trondhjemite intrusion. Gold-bearing veins post-date trondhjemite emplacement (ca. 2700 Ma), quartz diorite dikes (ca. 2667 Ma), and regional greenschist facies metamorphism. Textures and crosscutting relationships in gold-bearing veins indicate two stages of hydrothermal fluid infiltration associated with a single gold-related hydrothermal event: a volumetrically dominant, but gold-poor, stage I fluid and a gold-rich stage II fluid. Gold-bearing veins contain stage I milky quartz and pyrite that are overprinted by stage II quartz-ankerite-muscovite-chalcopyrite-sphalerite-galena-gold-tellurides ?? albite ?? chlorite ?? fuchsite ?? epidote ?? scheelite. Stage I hydrothermal alteration assemblages are different in trondhjemite and komatiite due to contrasting reactions between a common ore fluid and disparate wall-rock chemistry. Stage II fluid-wall rock interaction was minor compared to stage I and is indicated by the overprinting of stage I mineral assemblages by stage II microveins. Wall-rock alteration proximal to veins in trondhjemite is characterized by replacement of igneous plagioclase, amphibole, biotite, and metamorphic chlorite by hydrothermal quartz, muscovite, ankerite, calcite, pyrite, chalcopyrite, sphalerite, galena, tellurides, and gold, whereas in proximal alteration in komatiite, metamorphic chlorite and talc are replaced by ankerite, quartz, muscovite, albite, chlorite, fuchsite, pyrite, chalcopyrite, sphalerite, galena, tellurides, and gold. The stage II fluid was enriched in H2O, CO2, Si, Ca, K, Na, S, Au, Ag, Cu, Pb, W, Bi, As, Mo, Zn, and Te. Based on fluid inclusion

  12. Mars Express HRSC View of Western Olympus Mons: Evidence for Ice-bearing Deposit and High-Altitude Glaciation

    NASA Technical Reports Server (NTRS)

    Basilevsky, A. T.; Neukam, G.; Ivanov, B. A.; Werner, S. C.; vanGesselt, S.; Head, J. W.; Hauber, E.

    2005-01-01

    This study is based on the geological analysis of the HRSC images taken on the orbit 0143 (12 m/px in nadir channel). The study area includes the western segment of Olympus Mons and the adjacent lowland plains (Fig. 1). Part of the volcano above the scarp is rather flat and is called "summit plateau" below. What is often called the volcano scarp is a slope classified into three morphologic types: Type 1 (S1 in Fig.1) is the steepest and dominated by ravines in its upper part and by talus beneath; Type 2 (S2) is intermediate in steepness and dominated by downslope trending linear depressions, part of which have channel-like morphology; and Type 3 (S3), is the most gentle and covered by lava flows, continuing from the summit plateau down to the lowland plains.

  13. Soil mineral weathering in glacial deposits in the western Sierra Nevada and implication for U/Th geochronology

    NASA Astrophysics Data System (ADS)

    Aburto Guerrero, F. A.; Southard, R.

    2012-12-01

    During the Pleistocene vast alpine glaciers capped the Sierra Nevada range l and were a dominant force in shaping the post-glacial landscape. On the west side of the Lake Tahoe basin many moraine deposits stand out from the local morphology. Since their deposition these materials have been subject to physical and chemical weathering typical of this alpine environment. There is a general lack of information about soil weathering processes and rates for till deposits in alpine environments. We present the preliminary results of the mineralogical analysis of 13 granitic-derived soils located on Tioga (aprox. 19ka) and Tahoe age (aprox.118ka) moraine crests. A new light detection and ranging (LIDAR) dataset allowed geomorphic correlation of features using field reconnaissance and computer-based 3-D LIDAR data interpretation. A suite of mineralogical and elemental analyses, including XRD, DSC/TG and pXRF was performed, We also studied in-situ mineral transformations in selected durinodes by means of electron microprobe analysis and exploratory laser ablation coupled with mass spectrometry. Despite the large age difference in the deposits, Tahoe- and Tioga-age soils have very similar field morphology, making field discrimination extremely difficult. Mineralogical analysis reveals that soils on Tahoe-age moraines have clay mineralogy dominated by biotite and hydro-biotite, plus significant quantities of gibbsite and kaolinite. On the other hand, soils on Tioga-age moraines only have traces of gibbsite and kaolinite, and biotite is only slightly weathered. Elemental analysis suggests that Si and Al have been significantly mobilized exclusively in Tahoe-age soils. Increments in Al concentration coincide with relative gibbsite and kaolinite enrichment and plagioclase depletion. Si increment at deeper horizons seems to be associated with non-crystalline phases. Tioga-age durinodes are composed of till materials cemented by silica and contain coatings of micaceous materials

  14. Tectonic controls on deposition of Middle Jurassic strata in a retroarc foreland basin, Utah-Idaho trough, western interior, United States

    NASA Astrophysics Data System (ADS)

    Bjerrum, Christian J.; Dorsey, Rebecca J.

    1995-08-01

    An electronic supplement of this material may be obtained on a diskette or Anonymous FTP from KOSMOS.AGU.ORG. (LOGIN to AGU's FTP account using ANONYMOUS as the username and GUEST as the password. Go to the right directory by typing CD APEND. Type LS to see what files are available. Type GET and the name of the file to get it. Finally, type EXIT to leave the system.) (Paper 95TC01448, Tectonic controls on deposition of Middle Jurassic strata in a retroarc foreland basin, Utah-Idaho trough, western interior, United States, Christian J. Bjerrum and Rebecca J. Dorsey). Diskette may be ordered from American Geophysical Union, 2000 Florida Avenue, N. W., Washington, DC 20009; $15.00. Payment must accompany order. A thick succession of Jurassic nonmarine and marine sedimentary rocks is exposed in a large area from northern Arizona to eastern Idaho and western Wyoming. These sediments accumulated in the Utah-Idaho trough, a deep elongate cratonal basin whose origin has recently been debated. Detailed stratigraphic analysis, subsidence analysis, and first-order flexural modeling of these deposits (this study) provide new insights into the timing and mechanisms of subsidence in the Utah-Idaho trough. Lower and Middle Jurassic strata are divided into six unconformity-bounded sequences. In contrast to the overall uniform thickness of Lower Jurassic sequences (1 and 2), Middle Jurassic strata (sequences 3 through 6) consist of distinctly westward thickening sedimentary packages in which basal shallow marine deposits onlap eastward onto bounding unconformities. Basal strata of sequences 3 through 6 pass upward into widespread progradational continental deposits that are truncated progressively toward the east (cratonward) by the next unconformity. Decompacted total subsidence curves show that the rate of subsidence in most sections increased sharply at the end of sequence 2 time (J-2 unconformity; ˜170 Ma). This is interpreted to record the onset of Middle Jurassic deposition

  15. Spatial and temporal distribution of Cu-Au-Mo ore deposits along the western Tethyan convergent margin: a link with the 3D subduction dynamics

    NASA Astrophysics Data System (ADS)

    Menant, A.; Bertrand, G.; Loiselet, C.; Guillou-Frottier, L.; Jolivet, L.

    2012-12-01

    Emplacement conditions of mineralized systems in subduction and post-subduction environments and the sources of metals such as Cu, Mo and Au have been considered in the past. However, despite their importance in exploration strategies at the continental scale, interrelationships between distribution of ore systems and subduction dynamics are still partly unclear. Along the western Tethyan convergent margin, where Tertiary subduction history is well constrained, porphyry, epithermal and skarn ore deposits show a variable evolution of their spatial distribution. Using different and complementary database on European and Middle East ore deposits, three metallogenic episodes have been highlighted: (1) a late Cretaceous - Paleocene phase characterized by a copper mineralization within the Balkan chain and in the Kaçkar mountains (eastern Turkey), (2) an Eocene phase with a few copper ore deposits in eastern Turkey and small Caucasia and (3) an Oligocene - Neogene phase with a more southern distribution along the margin and mainly constituted by epithermal Au systems in the west (Carpathians, Rhodope, Aegean and western Turkey) and by porphyry copper deposits in the east (Zagros). These changes are suspected to be controlled by complex and evolving subduction dynamics. Using paleogeographic tools, it turned out that, in the eastern Mediterranean area, the late Cretaceous - Paleocene and Oligocene - Neogene metallogenic episodes are coeval with a significant decrease of the Africa - Eurasia convergence rate, from about 1.5 to 0.4 cm/yr. Indeed, compressional tectonics in the volcanic arc domain, associated with a high convergent rate, promote the storage of large volumes of metal-rich magma and the development of an extensive MASH (melting, assimilation, storage and homogenization) zone. When this convergence rate decreases, a stress relaxation occurs in the overriding crust, inducing the ascent of a sufficient flux of this fertile magma and allowing the formation of

  16. Full depositional cycles and Ca/Mg ratio in marine upper Baku regiostage succession in the Western flank of the South Caspian depression

    NASA Astrophysics Data System (ADS)

    Amirov, Elnur

    2010-05-01

    The results of the field works on exposures of the Lower Pleistocene deposits located in the Western flank of the South Caspian depression (Shikhov outcrop) demonstrated the high-frequency cyclicity in sedimentation accompanied by rapid lateral and vertical depositional environmental change. It is possible to observe several full depositional sequences developed from low stand system tract to transgressive system tract and high stand system tract. Return to sedimentation under conditions of sea level low stand marks beginning of the next depositional cycle. The depositional setting during accumulation of this succession has changed within shore face-shelf environment. On the background of these cycles, the depositional series of higher order containing sediments formed during very small-scale sea level fall and rise occur. Below I give the lithofacial characteristics of one full depositional cycle and our interpretation of depositional environment during its sedimentation. Bedset I is subdivided into 10 interbeds with total thickness 2m70cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone, organogenic limestone and shelly sandstone. We consider these series as high stand system tract. Bedset II is the massive and homogeneous, thickness 1m10cm. Lithologically represented by organogenic limestones. We consider these series as low stand system tract. Bedset III is subdivided into 7 interbeds with total thickness 1m5cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone, organogenic limestone and shelly sandstone. We consider these series as high stand system tract. Bedset IV is the massive and homogeneous, thickness 2m. Lithologically represented by organogenic limestones. We consider these series as low stand system tract. Bedset V is subdivided into 13 interbeds with total thickness 4m30cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone and

  17. Biological N2-Fixation Increases with Peatland Age and Decreases with N Deposition in Bogs of Western Canada

    NASA Astrophysics Data System (ADS)

    Fillingim, H.; Popma, J. M.; Dynarski, K. A.; Wieder, R.; Vile, M. A.

    2013-12-01

    Most terrestrial ecosystems are thought be limited primarily by nitrogen, including boreal peatlands located in pristine regions. Bogs receive nutrients solely from atmospheric deposition. Because of the historically low rates of atmospheric nitrogen deposition in Alberta, Canada, the Sphagnum mosses that dominate bog ground cover in this region have formed relationships with diazotrophs in order to meet their nitrogen needs, making biological N2- fixation the dominant input of new nitrogen to these bogs. The process of N2-fixation is highly variable and is governed by a number of environmental factors. In Alberta, one factor is water availability, as these bogs occur in some of the driest climates in which peatlands are known to exist. More recent factors with the potential to greatly alter N2-fixation dynamics include increasing nitrogen deposition associated with the growing oil sands mining operations and wildfires increasing in frequency and severity with global climate change. To determine the potential importance of N2-fixation to the overall peatland nitrogen balance under current and future conditions, we incubated the moss Sphagnum fuscum, using the acetylene reduction assay calibrated with 15N2, from 3 bogs representing ages of 3, 13, and 30 years since fire. Each bog was fertilized 8 times throughout the growing season with 0, 10, and 20 kg N/ha/yr. N2-fixation rates were measured 5 times at each site throughout the summer of 2013 to account for variation due to season and weather. Mean rates of N2-fixation increased with bog age, with higher rates in the 30 year old bog (36.90 × 8.38) and subsequently lower rates in the 13 yr (25.08 × 5.63) and 3 yr (11.58 × 6.33) old bogs. As expected, we saw decreasing rates of N2-fixation in the 10 (16.96 × 5.39) and 20 kg N/ha/yr treatments (3.35 × 1.34), as compared to water-only controls (47.62 × 12.18). These results indicate that N2-fixation supplies abundant N to support net primary productivity for bogs

  18. Atmospheric deposition of current-use and historic-use pesticides in snow at National Parks in the Western United States

    USGS Publications Warehouse

    Hageman, K.J.; Simonich, S.L.; Campbell, D.H.; Wilson, G.R.; Landers, D.H.

    2006-01-01

    The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and ??- hexachlorocyclohexane, whereas the most frequently detected historic-use pesticides were dieldrin, ??-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air. ?? 2006 American Chemical Society.

  19. Paleogeographical evolution of Vigla western Naxos (Cyclades, Greece), depositional environment and sea level changes in Upper Holocene.

    NASA Astrophysics Data System (ADS)

    Evelpidou, Niki; Pavlopoulos, Kosmas; Vassilopoulos, Andreas; Triantafyllou, Maria; Vouvalidis, Konstantinos; Syrides, George

    2010-05-01

    The study area of Vigla coastal zone is located at the W coast of Naxos, the largest island of Cycladic plateau. The study of sea-land interactions during Holocene in relation to the eustatic sea level oscillations as well as the geomorphologic observations and analyses on deposited sediments, aims to reveal the paleogeographic evolution of the landscape and its impact to the overall cultural development of the area. A geomorphological mapping of the coastal area along with the drilling of three boreholes has been accomplished. Moreover, a micro faunal analysis has been performed. Five samples of plant material, chart coal and shells were dated using AMS and Conventional radiocarbon techniques providing temporal control of the sediments. Sea level rise along with sea-land interactions to the landscape evolution and the transgression of sea in 5000 BP have been verified.

  20. Geology, petrography, geochemistry, and genesis of sulfide-rich pods in the Lac des Iles palladium deposits, western Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Duran, Charley J.; Barnes, Sarah-Jane; Corkery, John T.

    2016-04-01

    The Lac des Iles Pd deposits are known for their Pd-rich sulfide-poor mineralization. However, previously undocumented sulfide-rich pods also occur within the intrusion that hosts the deposits. Given the complex magmatic and hydrothermal history of the mineralization at Lac des Iles, the sulfide-rich pods could have crystallized from magmatic sulfide liquids or precipitated from hydrothermal fluids. Sulfide-rich pods occur throughout the stratigraphy, in all rock types, and along comagmatic shear zones, and contain net-textured to massive sulfides. They can be divided into four main groups based on the variation in mineral assemblages: (1) pyrrhotite-pentlandite ± pyrite-chalcopyrite-magnetite-ilmenite; (2) chalcopyrite ± pyrrhotite-pentlandite-pyrite-magnetite-ilmenite; (3) pyrite ± pentlandite-chalcopyrite-pyrrhotite-magnetite-ilmenite; and (4) magnetite ± ilmenite-pyrrhotite-pentlandite-pyrite-chalcopyrite. Whole rock metal contents and S isotopic compositions do not change with the amount of pyrite present, except for slight enrichments in As and Bi. The presence of an essentially magmatic sulfide mineral assemblage (pyrrhotite-pentlandite ± chalcopyrite) with pentlandite exsolution flames in pyrrhotite in some pods suggests that the pods crystallized from magmatic sulfide liquids. The very low Cu contents of the pods suggests that they are mainly cumulates of monosulfide solid solution (MSS). We propose a model whereby sulfide liquids were concentrated into dilation zones prior to crystallizing cumulus MSS. Intermediate solid solution crystallized from the fractionated liquids at the edges of some pods leaving residual liquids enriched in Pt, Pd, Au, As, Bi, Sb, and Te. These residual liquids are no longer associated with the pods. During subsequent alteration, pyrite replaced MSS/pyrrhotite, but this did not affect the platinum-group element contents of the pods.

  1. Coal depositional models in some Tertiary and Cretaceous coal fields in the U.S. Western Interior

    USGS Publications Warehouse

    Flores, R.M.

    1979-01-01

    Detailed stratigraphic and sedimentological studies of the Tertiary Tongue River Member of the Fort Union Formation in the Powder River Basin, Wyoming, and the Cretaceous Blackhawk Formation and Star Point Sandstone in the Wasatch Plateau, Utah, indicate that the depositional environments of coal played a major role in controlling coal thickness, lateral continuity, potential minability, and type of floor and roof rocks. The potentially minable, thick coal beds of the Tongue River Member were primarily formed in long-lived floodbasin backswamps of upper alluvial plain environment. Avulsion of meandering fluvial channels contributed to the erratic lateral extent of coals in this environment. Laterally extensive coals formed in floodbasin backswamps of a lower alluvial plain environment; however, interruption by overbank and crevasse-splay sedimentation produced highly split and merging coal beds. Lacustrine sedimentation common to the lower alluvial plain, similar to the lake-covered lower alluvial valley of the Atchafalaya River Basin, is related to a high-constructive delta. In contrast to these alluvial coals are the deltaic coal deposits of the Blackhawk Formation. The formation consists of three coal populations: upper delta plain, lower delta plain, and 'back-barrier'. Coals of the lower delta plain are thick and laterally extensive, in contrast to those of the upper delta plain and 'back-barrier', which contain abundant, very thin and laterally discontinuous carbonaceous shale partings. The reworking of the delta-front sediments of the Star Point Sandstone suggests that the Blackhawk-Star Point delta was a high-destructive system. ?? 1979.

  2. Geological and geochemical characteristics in the paleo-weathering crust sedimentary type REE deposits, western Guizhou, China

    NASA Astrophysics Data System (ADS)

    Zhou, Lingjie; Zhang, Zhengwei; Li, Yujiao; You, Fuhua; Wu, Chengquan; Zheng, Chaofei

    2013-09-01

    A supergene REE deposit closely interrelated with the weathering of the Emeishan basalt formation was produced in the Xuanwei formation, the overlying stratum of the late Permian Emeishan basalt formation in West Guizhou, China. The host strata consist primarily of offwhite kaolinite clay rock and/or grayish black carbonaceous shale. Mineralogical analyses reveal that kaolinites are the major minerals in REE ores with small amounts of smectite, illite, boehmite, hornblende, pyrophyllite, calcite, dolomite and/or iron-bearing minerals, with a certain proportion of feldspar, quartz crystal debris and noncrystal debris. Geochemical analyses reveal high enrichment of trace elements like Cu, Nb, Ta, Zr and Hf. The host strata feature considerable lithological variability, close interrelation of the REE grade with the lithology and uneven spatial distribution of the REE ores, which are mostly found in Lufang, Maojiaping and Zhangsigou profiles of Weining County and can be as thick as 20 m. Of the five stratigraphic profiles, 48% have their whole-rock ∑REE higher than 1000 ppm. The REE in this framework consists primarily of ion adsorbed phases and REE-rich residual independent mineral phases. Comprehensive analyses suggest that the source may not only include the Emeishan basalt, but the intermediate acid volcanic rocks evolved from the Emeishan basalt in the later periods; the hydrothermal alteration subsequently imposed on the host strata might have boosted the mineralization of the rare earth. The preliminary genetic model should have been: the denudation product from the weathering of the parent rock was migrated to the sea-continental margin at the continent side carrying huge quantities of REE with it and was preserved by the quick marine transgression. The host strata consist primarily of kaolinite clay rock and/or carbonaceous shale, which are so far believed to be a sedimentary type REE deposit closely interrelated with weathering effect.

  3. Allochthonous deep-water basin deposits of the western US: Implications for Paleozoic paleogeography and plate margin tectonics

    SciTech Connect

    Miller, E.L. . Geology Dept.)

    1993-04-01

    The stratigraphy and sedimentology of the lower Paleozoic Roberts Mts. and upper Paleozoic Golconda allochthons can be used to reconstruct their general paleogeographic setting in the Paleozoic. Basalt pillow lavas and radiolarian chert, were once considered straightforward evidence that the allochthons represented imbricated ocean crust formed at sites far removed from continental influences. Better stratigraphic definition, provenance studies and geochemistry of lavas now indicate that clastic components were derived from the continental shelf or interior and basalts in the Roberts Mountains allochthon were erupted in an intraplate setting through thinned continental crust (Madrid, 1987). Both in the earliest Mississippian and in the Late Permian, the Antler Basin (Roberts Mts.) and the Havallah Basin (Golconda) received proximal detritus from island arc sources to the west, immediately prior to closure of the basins by thrust-faulting. These data suggest that both systems of basins formed as marginal basins by rifting on the continental shelf (Antler Basin) and along the continental margin (Havallah Basin) and were flanked to the west by active island arcs at least during part of their history. As such, their stratigraphy provides a great deal of insight regarding tectonism along the western plate margin of North America during the Paleozoic.

  4. Age and depositional setting of the Permian Black Dyke Formation: Implications for the paleogeography and structural evolution of western Nevada

    NASA Astrophysics Data System (ADS)

    Bleina, O.; Lapierre, H.; Schweickert, R. A.; Pêcher, A.; Monié, P.; Maluski, H.; Charvet, J.

    1999-09-01

    In western Nevada, the Black Dyke Formation includes volcanic rocks overlain conformably by volcaniclastic sediments. At the base, hornblende-phyric basalts with cognate hornblende-bearing gabbroic cumulates are interbedded with tuffs and pyroclastic breccia. Amphiboles give 40Ar/ 39Ar ages of 276 Ma. Clinopyroxene-phyric pillow basalts and plagioclase-phyric andesitic lava flows are present higher in the section. Facies changes between exposures reflect development near volcanic centers. According to our investigations, the Black Dyke Formation is involved in east-west-trending folds overturned toward the south, and overlain unconformably by the Mesozoic Dunlap Formation, which unconformably overlies the Mississippian-Permian Mina Formation. Interpreted until now as tectonic slices within the Luning allochthon, we suggest that the Black Dyke Formation is part of the Sonoma allochthon associated with the Mina Formation. The Sonoma records closure of the Havallah basin (Golconda allochthon), and collision of an arctrench system with the North American margin. The Black Dyke Formation exhibits similarities with the Permian arc sequence of the northern Sierra Nevada. Both sequences are characterized by amphibole-bearing breccias, clinopyroxene-phyric pillow-basalts, plagioclase-phyric andesites and overlying volcaniclastic sediments. These sequences developed in the same geodynamic environment (an islandarc).

  5. Metasedimentary rocks of the Angara-Kan granulite-gneiss block (Yenisey Ridge, south-western margin of the Siberian Craton): Provenance characteristics, deposition and age

    NASA Astrophysics Data System (ADS)

    Urmantseva, L. N.; Turkina, O. M.; Larionov, A. N.

    2012-04-01

    The Angara-Kan granulite-gneiss block (Yenisey Ridge) is one of the main basements uplift within the south-western margin of the Siberian Craton. The major part of the Angara-Kan block is composed of Early Precambrian high-grade metamorphic rocks. Metasedimentary association of the Kan granulitic complex is composed of garnet-bearing, garnet-orthopyroxene and orthopyroxene-bearing gneisses, garnet- and orthopyroxene-bearing gneisses with cordierite and sillimanite. Studied paragneisses were formed at the expense of granulite metamorphism of terrigenous rocks, ranging from graywacke to pelitic rock or mudstone. To estimate the time of sedimentation and metamorphism of the terrigenous deposits, the U-Pb zircon dating has been performed using the SHRIMP II ion microprobe. Detrital zircon cores from the biotite-orthopyroxene and high-alumina gneisses yield ages of 2.6-1.94 and 2.4-1.94 Ga, respectively. Together with the age of the magmatic zircons formed during high-grade metamorphism and partial melting (˜1.89 Ga) and metamorphic rims (˜1.87 Ga) it defines the time of sedimentation between 2.0-1.94 and 1.89-1.87 Ga. Detrital zircon ages indicate both Archean and Paleoproterozioc rocks in provenance source, that agrees with the Nd model ages of metasediments ranging in interval 2.4-2.8 Ga. Potential source of the Archean detrital zircons was the exposed basement of the southwestern Siberian Craton, whereas the Paleoproterozoic juvenile crustal source seems to be buried basement of the Tungus province of the Siberian Craton. Deposition of the Kan terrigeneous rocks was coeval with sedimentation in the southeastern part of the Sharyzhalgay uplift, where ages of detrital zircon cores and metamorphic rims from paragneisses bracket sediment deposition between 1.95 and 1.85 Ga.

  6. Geology, geochemistry and mineralogy of the lignite-hosted Ambassador palaeochannel uranium and multi-element deposit, Gunbarrel Basin, Western Australia

    NASA Astrophysics Data System (ADS)

    Douglas, Grant B.; Butt, Charles R. M.; Gray, David J.

    2011-10-01

    The Ambassador U and multi-element deposit occurs on the SW margin of the Gunbarrel Basin, Western Australia. Low-grade, flat-lying U mineralization averaging about 2 m thick at 0.03% U occurs in lignites at the redox front at the base of the weathering profile within a laterally extensive palaeochannel network. Uranium is principally associated with organic matter within the lignitic matrix, although rare discrete U minerals, such as coffinite and uraninite, are also present. The lignite is also enriched in a suite of other elements, principally base metals and sulphur, with concentrations of 0.3 ≥ 1% Cu, Pb, Ni, Co, Zn and total rare earth elements (REE) in some samples. Other element enrichments include: Cr, Cs, Sc, Se, Ta, Ti, Th, V and Zr as detrital heavy minerals of Zr, Ti and REE (oxides and silicates) or authigenic minerals of Cu, Bi, Pb, Zn, Ni, Se, Hg, Ti, Cr, Tl, V, U and REE (sulphides, vanadates, selenides, oxides, chlorides and native metals) and diffuse lignite impregnations. The Ambassador deposit probably formed from the convergence of redox-active weathering processes to unique source/host rocks, constrained within the palaeochannel. A proximal source of U and trace elements of lamproite/carbonatite origin is probable, as constrained by U-Pb isotope and U-Th disequilibria studies. Uranium and other metals were precipitated syngenetically with organic matter as it was deposited during a humid phase in the Late Eocene. Remobilization subsequently concentrated the metals in the upper 2 m of the lignite. This may have occurred during one or more periods of weathering and associated diagenesis, with the latest episode in the last 300,000 years.

  7. Dips, ramps, and rolls- Evidence for paleotopographic and syn-depositional fault control on the Western Kentucky No. 4 coal bed, tradewater formation (Bolsovian) Illinois Basin

    USGS Publications Warehouse

    Greb, S.F.; Eble, C.F.; Williams, D.A.; Nelson, W.J.

    2001-01-01

    The Western Kentucky No. 4 coal is a high-volatile B to high-volatile C bituminous coal that has been heavily mined along the southern margin of the Western Kentucky Coal Field. The seam has a reputation for rolling floor elevation. Elongate trends of floor depressions are referred to as "dips" and "rolls" by miners. Some are relatively narrow and straight to slightly curvilinear in plan view, with generally symmetric to slightly asymmetric cross-sections. Others are broader and asymmetric in section, with sharp dips on one limb and gradual, ramp-like dips on the other. Some limbs change laterally from gradual dip, to sharp dip, to offset of the coal. Lateral changes in the rate of floor elevation dip are often associated with changes in coal thickness, and in underground mines, changes in floor elevation are sometimes associated with roof falls and haulage problems. In order to test if coal thickness changes within floor depressions were associated with changes in palynology, petrography and coal quality, the coal was sampled at a surface mine across a broad. ramp-like depression that showed down-dip coal thickening. Increment samples of coal from a thick (150 cm), down-ramp and thinner (127 cm), up-ramp position at one surface mine correlate well between sample sites (a distance of 60 m) except for a single increment. The anomalous increment (31 cm) in the lower-middle part of the thick coal bed contained 20% more Lycospora orbicula spores. The rolling floor elevations noted in the study mines are inferred to have been formed as a result of pre-peat paleotopographic depressions, syn-depositional faulting, fault-controlled pre-peat paleotopography, and from compaction beneath post-depositional channels and slumps. Although the association of thick coal with linear trends and inferred faults has been used in other basins to infer syn-depositional faulting, changes in palynology within increment samples of the seam along a structural ramp in this study provide

  8. Water Availability for Shale Gas Development in Sichuan Basin, China.

    PubMed

    Yu, Mengjun; Weinthal, Erika; Patiño-Echeverri, Dalia; Deshusses, Marc A; Zou, Caineng; Ni, Yunyan; Vengosh, Avner

    2016-03-15

    Unconventional shale gas development holds promise for reducing the predominant consumption of coal and increasing the utilization of natural gas in China. While China possesses some of the most abundant technically recoverable shale gas resources in the world, water availability could still be a limiting factor for hydraulic fracturing operations, in addition to geological, infrastructural, and technological barriers. Here, we project the baseline water availability for the next 15 years in Sichuan Basin, one of the most promising shale gas basins in China. Our projection shows that continued water demand for the domestic sector in Sichuan Basin could result in high to extremely high water stress in certain areas. By simulating shale gas development and using information from current water use for hydraulic fracturing in Sichuan Basin (20,000-30,000 m(3) per well), we project that during the next decade water use for shale gas development could reach 20-30 million m(3)/year, when shale gas well development is projected to be most active. While this volume is negligible relative to the projected overall domestic water use of ∼36 billion m(3)/year, we posit that intensification of hydraulic fracturing and water use might compete with other water utilization in local water-stress areas in Sichuan Basin. PMID:26881457

  9. Depositional cycles and Fe/Mn ratio in Upper Absheron substage succession in the western flank of the South Khazarian/Caspian depression of the Azerbaijan Republic

    NASA Astrophysics Data System (ADS)

    Amirov, Elnur

    2016-04-01

    The Caspian Sea, the largest land locked basin in the world, isolated from ParaTethys at the end of Messinian. Since that time sedimentation there took place under conditions of isolated basin temporarily connected with Black Sea in Upper Pliocene (Akchagyl). For the first time very detailed study (centimeter scale) of outcrop was carried out for stratigraphy and paleoecology of the Upper absheron substage deposits cropped out in the Western flank of the South Caspian depression (Shikhovo exposure) of the Azerbaijan Republic. The data obtained demonstrated the high-frequency cyclicity in sedimentation accompanied by rapid lateral and vertical depositional environment change. Most of these system tracts have not yet been studied in detail. The depositional setting during accumulation of this succession has changed within shore face-shelf environment. On the background of these cycles, the depositional series of a higher order containing sediments deposited during very small-scale sea level fall and rise occur. Some information contained in this document is the new data, due to more recent observations and interpretations. The results of the field works on exposures of the Eopleistocene deposits exposed in the Western flank of the South Caspian depression (Shikhovo outcrop) demonstrated the high-frequency cyclicity in sedimentation. It is possible to observe several full depositional sequences developed from transgressive system tract to low stand system tract, to high stand system tract and return to sedimentation under conditions of sea level rise. The studied successions are characterized by steep foresets, about 12°, which is evidence of steep slope existed during the sediment accumulation. On the background of above mentioned cycles, the depositional series of a higher order containing sediments formed during very small-scale sea level fall and rise occur. Below we give the lithofacial characteristics of one full depositional cycle and our interpretation of

  10. Land-sea correlation between Late Holocene coastal and infralittoral deposits in the SE Iberian Peninsula (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Fernández-Salas, L. M.; Dabrio, C. J.; Goy, J. L.; Díaz del Río, V.; Zazo, C.; Lobo, F. J.; Sanz, J. L.; Lario, J.

    2009-03-01

    The well-exposed systems of prograding beach ridges on the Carchuna-Calahonda (Granada) and Campo de Dalías-Roquetas (Almería) coastal plains continue offshore as infralittoral prograding wedges (IPW). The Holocene IPW is a narrow morpho-sedimentary unit up to 2.5 km wide which develops seaward from the lower edge of the shoreface to 15-20 m depth, extending to a well-defined break of slope at water depths of 35-40 m. These IPWs have been recognized and studied using very high-resolution seismic profiles (TOPAS) and multibeam data (EM-3000D). In detail they are complex morpho-sedimentary units in which internal structures are closely linked to the pattern of progradation of the adjacent coastal plains. When longshore currents produce significant littoral drift, the IPWs are composed of several minor units arranged in offlap, which accrete parallel or oblique to the main shoreline. Therefore, it is possible to correlate progradational units in the coastal plain (H-units, sensu[Goy, J.L., Zazo, C., Dabrio, C.J., 2003. A beach-ridge progradation complex reflecting periodical sea-level and climate variability during the Holocene (Gulf of Almería, Western Mediterranean). Geomorphology 50, 251-268]) and subunits in the IPW, but special care is required depending on the local arrangement of morpho-sedimentary units. Besides, it is not realistic to draw conclusions regarding the age of the subunits inside a given IPW without adequate dating, as the number of subunits will greatly vary from place to place depending on local factors, magnitude of sea-level oscillations, and sediment supply.

  11. SHRIMP U-Pb geochronology of volcanic rocks, Belt Supergroup, western Montana: Evidence for rapid deposition of sedimentary strata

    USGS Publications Warehouse

    Evans, K.V.; Aleinikoff, J.N.; Obradovich, J.D.; Fanning, C.M.

    2000-01-01

    New sensitive high resolution ion microprobe (SHRIMP) U-Pb zircon analyses from two tuffs and a felsic flow in the middle and upper Belt Supergroup of northwestern Montana significantly refine the age of sedimentation for this very thick (15-20 km) Middle Proterozoic stratigraphic sequence. In ascending stratigraphic order, the results are (1) 1454 ?? 9 Ma for a tuff in the upper part of the Helena Formation at Logan Pass, Glacier National Park; (2) 1443 ?? 7 Ma for a regionally restricted porphyritic rhyolite to quartz latite flow of the Purcell Lava in the Yaak River region; and (3) 1401 ?? 6 Ma for a tuff in the very thin transition zone between the Bonner Quartzite and Libby Formation, west of the town of Libby. Combining these ages with those previously published by other workers for ca. 1470-Ma sills in the lower Belt in Montana and Canada indicates that all but the uppermost Belt strata (about 1700 m) were deposited over a period of about 70 million years, considerably reducing the time span from longstanding estimates ranging from 250 to 600 million years. Calculated sediment accumulation rates between dated samples indicates rapid, but not unreasonable, values for early Belt strata, with decreasing rates through time. These ages also suggest the inadequacy of previously published paleomagnetic data to resolve Belt Supergroup chronology at an appropriate level of accuracy.

  12. Phosphate and sulfate-phosphate mineralization in sillimanite-bearing rocks at the Kyakhta deposit, western Transbaikal region

    NASA Astrophysics Data System (ADS)

    Izbrodin, I. A.; Ripp, G. S.; Karmanov, N. S.

    2009-12-01

    The phosphate and sulfate-phosphate minerals in the sillimanite-bearing rocks of the Kyakhta deposit are considered. The mineral assemblages of the high-Al rocks were formed during prograde and retrograde stages of metamorphism. The first stage is characterized by the formation of sillimanite, corundum, muscovite, quartz, rutile, titanohematite, magnetite, feldspar, biotite, lazulite, and wagnerite. The muscovite composition showed that sillimanite paragenesis was formed at temperatures above 510-600°C. According to oxygen isotope thermometry, the minimum metamorphic temperature for quartz and titanohematite is 690°C. Andalusite, diaspore, quartz, pyrophyllite, muscovite, and a wide range of phosphates and sulfate-phosphates crystallized during the retrograde stage. The decrease in temperature and increase in the water content led to the following sequence of mineral formation: Mg-Fe-Al-Ca-REE-rich phosphates (lazulite, scorzalite, augelite, apatite, and monazite) → Ca-Sr sulfate-phosphates (woodhouseite and svanbergite) → sulfate (barite) → Sr-Ca-Ba aluminophosphates (goyazite, crandallite, and gorceixite). The chemical compositions of phosphates and sulfate-phosphates minerals and their formation conditions are discussed.

  13. Foraminiferal biostratigraphy of the Toarcian deposits (Lower Jurassic) from the Middle Atlas (Morocco). Comparison with western Tethyan areas

    NASA Astrophysics Data System (ADS)

    Bejjaji, Zohra; Chakiri, Saïd; Reolid, Matías; Boutakiout, Mohamed

    2010-04-01

    The Toarcian sediments of the Middle Atlas show hemipelagic facies deposited in platform to basinal environments. They are represented by: (a) marly thick sections that accumulated in troughs under restricted dysoxic conditions, and (b) condensed sections of marly limestones found on fairly high ridges. The micropaleontological study of benthic foraminifera allowed us to establish the biostratigraphic extension of the different registered species. From the stratigraphic distribution of the benthic foraminifera two renewal phases can be characterized: one at the base of the Polymorphum Zone, and the other inside the Bifrons Zone. Five biozones were thus established ( Lingulina gr. tenera and Marginulina gr. prima Biozone; Lenticulina obonensis mg Planularia Biozone; Lenticulina pennensis mg Marginulinopsis and Ichtyolaria hauffi Biozone; Nodosariapulchra and Lenticulina ferruginea mg Falsopalmula Biozone; Lenticulinadorbignyi Biozone). These stratigraphic sub-divisions based on the benthic foraminifera are a useful tool when ammonoids are scarce. The Toarcian benthic foraminifera of the Middle Atlas are similar to the foraminiferal associations from neighbouring regions in the Maghreb (Morocco and Algeria) and Southwestern Europe (Spain, France and Portugal).

  14. Effect of nine years of animal waste deposition on profile distribution of heavy metals in Abeokuta, south-western Nigeria and its implication for environmental quality.

    PubMed

    Azeez, J O; Adekunle, I O; Atiku, O O; Akande, K B; Jamiu-Azeez, S O

    2009-09-01

    Uncontrolled deposition of waste from animal farms is a common practice in south-western Nigeria, and the presence of heavy metals in soil constitutes environmental and health hazards by polluting the soil, ground water, adjoining streams and rivers. The study investigated the profile distribution of Mn, Pb, Cd, Zn, Fe, Cu, Ni and Cr in some tropical Alfisols in south-western Nigeria after nine years disposal of animal wastes. The amount of these metals in the soil horizons was high enough to cause health and phytotoxic risks. All the metals except Zn and Cr increased down the profile, while Mn, Pb, Cd, Fe, Cu and Ni accumulated at 80-120 cm depth. The increment of these metals at this depth over the top soil were 26%, 143%, 72%, 47%, 328% for Mn, Pb, Cd, Cu and Ni, respectively. It thus, shows their mobility and the possibility of polluting ground water. The Mn content at the poultry and cattle waste sites increased by 127% and 25%, respectively over the control, while that of cattle and swine dump site for Cd content were 9.82 and 15.63 mg kg(-1), respectively. Lead content also increased by 8.52 and 5.25 mg kg(-1), respectively. There was the accumulation of Zn and Cu at the swine dump site while the cattle dump site had the highest amounts of nickel and chromium. The least amount of Fe was recorded at the swine waste dump site. The reduction in organic matter with depths together with the reduced pH might have favored the mobility of the metals. The ranking of pollution among the sites was poultry>swine>cattle>sheep and could be due to the type of ration fed, the vaccination programmes, sanitation programmes and other management practices. PMID:19525105

  15. Slip rate estimation along the western segment of the Main Marmara Fault over the last 405-490 ka by correlating mass transport deposits

    NASA Astrophysics Data System (ADS)

    Grall, C.; Henry, P.; Thomas, Y.; Westbrook, G. K.; ćaǧatay, M. N.; Marsset, B.; Saritas, H.; ćifçi, G.; Géli, L.

    2013-12-01

    3-D seismic data acquired in the Sea of Marmara on the Western High, along the northwestern branch of the North Anatolian Fault (also known as the Main Marmara Fault), shed new light on the evolution of the deformation over the last 500-600 ka. Sedimentary sequences in ponded basins are correlated with glacioeustatic cycles and transitions between marine and low sea/lake environments in the Sea of Marmara. In the 3 × 11 km2 of the 3-D seismic survey, deformation over the last 405-490 ka is localized along the main fault branch and north of it, where N130°-N140° trending normal faults and N40°-N50° folding accommodated strike-slip deformation associated with active argillokinesis. There is some evidence that deformation was more distributed further back in the past, at least over the depth range (<600 m below seafloor) of our survey. A N110° basin and buried ridge system were eventually cut by the presently active fault. The southern part of the basin was then uplifted, while the northern part was folded but continued to subside along the fault. A mass transport deposits complex dated between 405-490 ka shows a lateral displacement of 7.7 ± 0.3 km, corresponding to an estimated slip rate of 15.1-19.7 mm/a. We conclude that this strand of the Main Marmara Fault on the Western High has taken up most of the strike slip motion between the Anatolian and Eurasian plates over the last 405 ka at least.

  16. Decadal trend of black carbon and refractory carbonaceous aerosol in the western rim of the North Pacific Ocean: atmospheric concentration and the retrieved record of deposition flux

    NASA Astrophysics Data System (ADS)

    Kaneyasu, Naoki; Yamaguchi, Takashi; Noguchi, Izumi; Akiyama, Masayuki; Matsumoto, Kiyoshi

    2013-04-01

    The long-term trend of light absorbing carbonaceous aerosols (or black carbon: BC) or refractory carbonaceous aerosol (or elemental carbon: EC) concentration is reported at European background sites such as Mace Head, and that of aerosol absorption coefficient are monitored in many GAW sites. On the contrary, such long-term data are relatively scarce at around the western part of the North Pacific Ocean. Thus, to understand the long-term variation of in the area, BC in fine aerosol fraction has been measured at Chichi-jima Islands, Japan. Chichi-jima Island is located 1000 km south of the Japanese mainland, and 1800 km west of the coast line of the Asian continent. BC has been measured with an Aethalometer (Magee, AE-16 and AE-30) since December, 1998 with 1 hr time resolution. Mass flowmeter embedded inside the Aethalometer is calibrated with a rotational dry gas-meter once a year. Monthly averaged BC concentration shows an obvious seasonal variation, i.e. high concentration during late autumn-winter-spring period resulting from the transport from East Asia, with maximum daily concentration above 500 ng m-3. In summer, daily concentration was usually less than 20 ng m-3, due to the clean background airmass originating from the North Pacific Anticyclone. Decadal trend of the annual averaged BC concentration showed a increasing trend from 2000 to 2007 and started to decrease after 2008, which roughly coincides with the reported emission trend of SO2 in China (Lu et al., 2010). In addition, total (i.e., wet + dry) deposition record of refractory carbon at two sites in the northern Japan (Rishiri Island: a remote island site, and Sapporo City: an urban site) are retrieved. At these sites, the local government have been measuring the chemical components in precipitation water collected by deposition gauges. In the deposition gauge, a membrane filter made of cellulose-acetate is fixed at the bottom of the funnel to remove water-insoluble particles from the precipitated

  17. [Agro-ecosystem ammonia emission in Sichuan-Chongqing region].

    PubMed

    Li, Fu-chun; Han, Shen-hui; Yang, Jun; Zhang, Xu; Li, Ru-yan; Wei, Yuan-song; Fan, Mao-hong

    2009-10-15

    Ammonia (NH3) emission from agro-ecosystem in the Sichuan-Chongqing region during 1990-2004, was estimated by the regional nitrogen cycling model IAP-N. The county level agricultural activities data were used, and Sichuan-Chongqing region was divided into four sub-areas by the geographical characteristics , environment and local climatic conditions and administrative division. The results showed that average annual ammonia emissions (in nitrogen gauge) in 1990-1994, 1995-1999, 2000-2004 were 626.7, 670.5 and 698.8 Gg x a(-1) respectively. The ammonia emission appeared increasing trend, whereas, the contribution of various ammonia sources presented little change. For instance, in 2000-2004, the contributions of NH3 emission from fertilized cropland, manure management system and field residues burning to the total ammonia emission of agro-ecosystem in the Sichuan-Chongqing region were 53%, 46% and 1%, equals to 374.9, 318.2 and 5.6 Gg x a(-1) respectively. But the contributions were variable in different regions. Ammonia emission was primarily induced by fertilized cropland in Chengdu plain and Chongqing hilly area, whereas, in northwest sub-region of Sichuan province was manure management system. The geographical distribution of ammonia emission from agro-ecosystem in the Sichuan-Chongqing region was generally "east high and west low". Ammonia emissions in sub-regions of Chongqing hilly area, Chengdu plain, southwest and northwest sub-regions were 165.6, 408.8, 85.9 and 38.8 Gg x a(-1), respectively, during 2000-2004. At the same time, ammonia density were 20 and 28 kg x (hm2 x a)(-1) in sub-regions of the Chongqing hilly area and the Chengdu plain, whereas, 9.1 and 1.6 kg x (hm2 x a)(-1) in southwest and northwest sub-regions, respectively. The results will provide a scientific basis for making fertilizer effectively applied and mitigate NH3 and GHG emissions from agro-ecosystem of Sichuan-Chongqing region. PMID:19968093

  18. Probabilistic Analysis of Earthquake-Led Water Contamination: A Case of Sichuan, China

    NASA Astrophysics Data System (ADS)

    Yang, Yan; Li, Lin; Benjamin Zhan, F.; Zhuang, Yanhua

    2015-12-01

    The objective of this paper is to evaluate seismic-led point source and non-point source water pollution, under the seismic hazard of 10 % probability of exceedance in 50 years, and with the minimum value of the water quality standard in Sichuan, China. The soil conservation service curve number method of calculating the runoff depth in the single rainfall event combined with the seismic damage index were applied to estimate the potential degree of non-point source water pollution. To estimate the potential impact of point source water pollution, a comprehensive water pollution evaluation framework is constructed using a combination of Water Quality Index and Seismic Damage Index methods. The four key findings of this paper are: (1) The water catchment that has the highest factory concentration does not have the highest risk of non-point source water contamination induced by the outbreak of potential earthquake. (2) The water catchment that has the highest numbers of cumulative water pollutants types are typically located in the south western parts of Sichuan where the main river basins in the regions flow through. (3) The most common pollutants in sample factories studied is COD and NH3-N which are found in all catchments. The least common pollutant is pathogen—found present in W1 catchment which has the best rating in the water quality index. (4) Using water quality index as a standardization parameter, parallel comparisons is made among the 16 water catchments. Only catchment W1 reaches level II water quality status which has the rating of moderately polluted in events of earthquake induced water contamination. All other areas suffer from severe water contamination with multiple pollution sources. The results from the data model are significant to urban planning commissions and businesses to strategically choose their factory locations in order to minimize potential hazardous impact during the outbreak of earthquake.

  19. Active tectonic characteristics of river terraces along the Tianquan River, Sichuan, China

    NASA Astrophysics Data System (ADS)

    Cai, Y. M.; Shyu, J. B. H.; Chang, C. P.

    2015-12-01

    The Longmenshan fold-and-thrust belt at the western edge of the Sichuan Basin has long been identified as an active tectonic belt. This has been clearly illustrated by the disastrous Wenchuan and Lushan earthquakes in the recent decade. The two earthquakes, however, have distinctive characters. In the north, the Wenchuan event occurred on major fault zones identified previously. But in the south, the Lushan event was not accompanied by surface ruptures, and the seismogenic structure is still under debate. In order to further understand the neotectonic characteristics of the Lushan earthquake region, we analyzed fluvial terraces, in the hope that such geomorphic features would provide information of active structures of the area. Along the Tianquan River, river terraces are particularly well developed near two cities, Tianquan and Shiyang. Since the terraces appear to be very wide and limited in these two basin-like areas, we suspected that they formed as filled-up lakes. However, after detailed field investigations, we found that underneath these terraces, early Tertiary bedrocks crop out below river sediments that are only several meters thick. This indicates that the Tianquan River has incised into bedrocks. The slope of the terrace surfaces is similar to that of the present-day riverbed, and the river sediments in the terrace outcrops have similar grain size distribution as current riverbed sediments. Therefore, we suggest that the terraces along the Tianquan River are not related to dammed lake, but were produced by tectonic uplift. Combining the age of terrace sediments dated by optically stimulated luminescence (OSL) and detailed topography of the terrace surfaces, we aim to establish a model for the formation mechanism of these two terrace groups. We hope the results of this study would provide more information of neotectonic characteristics of the southwestern Sichuan Basin, as well as future earthquake hazards in this densely populated region.

  20. Probabilistic Analysis of Earthquake-Led Water Contamination: A Case of Sichuan, China

    NASA Astrophysics Data System (ADS)

    Yang, Yan; Li, Lin; Benjamin Zhan, F.; Zhuang, Yanhua

    2016-06-01

    The objective of this paper is to evaluate seismic-led point source and non-point source water pollution, under the seismic hazard of 10 % probability of exceedance in 50 years, and with the minimum value of the water quality standard in Sichuan, China. The soil conservation service curve number method of calculating the runoff depth in the single rainfall event combined with the seismic damage index were applied to estimate the potential degree of non-point source water pollution. To estimate the potential impact of point source water pollution, a comprehensive water pollution evaluation framework is constructed using a combination of Water Quality Index and Seismic Damage Index methods. The four key findings of this paper are: (1) The water catchment that has the highest factory concentration does not have the highest risk of non-point source water contamination induced by the outbreak of potential earthquake. (2) The water catchment that has the highest numbers of cumulative water pollutants types are typically located in the south western parts of Sichuan where the main river basins in the regions flow through. (3) The most common pollutants in sample factories studied is COD and NH3-N which are found in all catchments. The least common pollutant is pathogen—found present in W1 catchment which has the best rating in the water quality index. (4) Using water quality index as a standardization parameter, parallel comparisons is made among the 16 water catchments. Only catchment W1 reaches level II water quality status which has the rating of moderately polluted in events of earthquake induced water contamination. All other areas suffer from severe water contamination with multiple pollution sources. The results from the data model are significant to urban planning commissions and businesses to strategically choose their factory locations in order to minimize potential hazardous impact during the outbreak of earthquake.

  1. Western Samoa.

    PubMed

    1985-12-01

    agricultural, and the village communities maintain an economy based on farming and fishing. Stagnating or declining agricultural production has resulted in an increasing dependence on imports. The islands have few resources and no deposits of commercially valuable minerals. Western Samoa suffers from a persistent current accounts deficit. The government's primary goal is to improve agricultural production. Western Samoa has particularly close relations with its Pacific island neighbors and New Zealand. The US has taken a special interest in Western Samoa's economic development. PMID:12178131

  2. Dynamic responses of the benthic bacterial community at the Western English Channel observatory site L4 are driven by deposition of fresh phytodetritus

    NASA Astrophysics Data System (ADS)

    Tait, Karen; Airs, Ruth L.; Widdicombe, Claire E.; Tarran, Glen A.; Jones, Mark R.; Widdicombe, Stephen

    2015-09-01

    The impact of the seasonal deposition of phytoplankton and phytodetritus on surface sediment bacterial abundance and community composition was investigated at the Western English Channel site L4. Sediment and water samples were collected from January to September in 2012, increasing in frequency during periods of high water column phytoplankton abundance. Compared to the past two decades, the spring bloom in 2012 was both unusually long in duration and contained higher than average biomass. Within spring months, the phytoplankton bloom was well mixed through the water column and showed accumulations near the sea bed, as evidenced by flow cytometry measurements of nanoeukaryotes, water column chlorophyll a and the appearance of pelagic phytoplankton at the sediment. Measurements of chlorophyll and chlorophyll degradation products indicated phytoplankton material was heavily degraded after it reached the sediment surface: the nature of the chlorophyll degradation products (predominantly pheophorbide, pyropheophorbide and hydroxychlorophyllone) was indicative of grazing activity. The abundance of bacterial 16S rRNA genes g-1 sediment (used as a proxy for bacterial biomass) increased markedly with the onset of the phytoplankton bloom, and correlated with measurements of chlorophyll at the surface sediment. Together, this suggests that bacteria may have responded to nutrients released via grazing activity. In depth sequencing of the 16S rRNA genes indicated that the composition of the bacterial community shifted rapidly through-out the prolonged spring bloom period. This was primarily due to an increase in the relative sequence abundance of Flavobacteria.

  3. Composition and origin of fluids associated with lode gold deposits in a Mesoarchean greenstone belt (Warrawoona Syncline, Pilbara Craton, Western Australia) using synchrotron radiation X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Thébaud, Nicolas; Philippot, Pascal; Rey, Patrice; Cauzid, Jean

    2006-10-01

    Microthermometry and Raman spectroscopy techniques are routinely use to constrain ore-fluids δ18O and molar proportions of anhydrous gas species (CO2, CH4, N2). However, these methods remain imprecise concerning the ore-fluids composition and source. Synchrotron radiation X-ray fluorescence allows access to major and trace element concentrations (Cl, Br and K, Ca, Fe, Cu, Zn, As, Rb, Sr) of single fluid inclusion. In this paper, we present the results of the combination of these routine and newly developed techniques in order to document the fluids composition and source associated with a Mesoarchaean lode gold deposit (Warrawoona Syncline, Western Australia). Fluid inclusion analyses show that quartz veins preserved records of three fluid inclusion populations. Early fluids inclusions, related to quartz veins precipitation, are characterized by a moderate to high Br/Cl ratio relative to modern seawater, CO2 ± CH4 ± N2, low to moderate salinities and significant base metal (Fe, Cu, Zn) and metalloid (As) concentrations. Late fluid inclusions trapped in secondary aqueous fluid inclusions are divided into two populations with distinct compositions. The first population consists of moderately saline aqueous brines, with a Br/Cl ratio close to modern seawater and a low concentration of base metals and metalloids. The second population is a fluid of low to moderate salinity, with a low Br/Cl ratio relative to modern seawater and significant enrichment in Fe, Zn, Sr and Rb. These three fluid inclusion populations point to three contrasting sources: (1) a carbonic fluid of mixed metamorphic and magmatic origin associated with the gold-bearing quartz precipitation; (2) a secondary aqueous fluid with seawater affinity; and (3) a surface-derived secondary aqueous fluid modified through interaction with felsic lithologies, before being flushed into the syncline. Primary carbonic fluids present similar characteristics than those ascribed to Mesoarchaean lode gold deposits

  4. Senecio changii (Asteraceae: Senecioneae), a New Species from Sichuan, China

    PubMed Central

    Ren, Chen; Tong, Tian-Jing; Hong, Yu; Yang, Qin-Er

    2016-01-01

    Senecio changii (Asteraceae: Senecioneae), a new species from Muli, Sichuan, southwestern China, is described. It is distinguished in Chinese Senecio s.s. by having lyrate-pinnatisect to pinnatisect leaves and a single terminal large discoid capitulum which is somewhat nodding. Evidence from floral micromorphology, karyology and molecular phylogenetic analyses based on the nuclear ITS/ETS sequence data all support its membership within Senecio s.s. PMID:27050905

  5. Senecio changii (Asteraceae: Senecioneae), a New Species from Sichuan, China.

    PubMed

    Ren, Chen; Tong, Tian-Jing; Hong, Yu; Yang, Qin-Er

    2016-01-01

    Senecio changii (Asteraceae: Senecioneae), a new species from Muli, Sichuan, southwestern China, is described. It is distinguished in Chinese Senecio s.s. by having lyrate-pinnatisect to pinnatisect leaves and a single terminal large discoid capitulum which is somewhat nodding. Evidence from floral micromorphology, karyology and molecular phylogenetic analyses based on the nuclear ITS/ETS sequence data all support its membership within Senecio s.s. PMID:27050905

  6. Timing and duration of supergene mineralization at the Xinrong manganese deposit, western Guangdong Province, South China: cryptomelane 40Ar/39Ar dating

    NASA Astrophysics Data System (ADS)

    Li, Jian-Wei; Vasconcelos, Paulo; Zhang, Wei; Deng, Xiao-Dong; Duzgoren-Aydin, Nurdan; Yan, Dai-Rong; Zhang, Jian-Qiang; Hu, Ming-An

    2007-04-01

    Supergene Mn-oxide deposits are widely distributed in Guangxi, Guangdong, Yunnan, and Hunan Provinces, South China, accounting for 18% of the total Mn reserves in the country. Direct dating of supergene Mn enrichment, however, is lacking. In this paper, we present high-resolution 40Ar/39Ar ages of Mn oxides from the Xinrong Mn deposit, western Guangdong, to place numerical constraints on the timing and duration of supergene Mn enrichment. A total of ten cryptomelane samples, spanning a vertical extent of 67 m, were dated using the 40Ar/39Ar laser incremental heating technique, with seven samples yielding well-defined plateau or pseudo-plateau ages ranging from 23.48 ± 0.91 to 2.06 ± 0.05 Ma (2 σ). One sample yields a staircase spectrum that does not reach a plateau; the spectrum, however, indicates the presence of two or more generations of Mn oxides in the sample, whose ages are best estimated at 22.34 ± 0.31 and 10.2 ± 0.86 Ma, respectively. The remaining two samples gave meaningless or uninterpretable results due to significant 39Ar recoil and contamination by old phases. The 40Ar/39Ar data thus reveal a protracted history of weathering and supergene Mn enrichment that started at least in the end of the Oligocene or beginning of Miocene and extending into the latest Pliocene. Staircase-apparent age spectra, resulting from banded or botryoidal samples, yield an average growth rate of Mn oxides at 0.6-0.7 × 10-3 mm kyr-1. The values indicate that a 1-mm grain of Mn oxides may host minerals precipitated during a time span of ca. 1.5 m.y., and accumulation of Mn oxides to form economic deposits under weathering environments may take millions of years. The distribution of weathering ages shows that the oldest Mn oxides occur on the top of the profile, whereas the youngest minerals are found at the bottom, suggesting downward propagation of weathering fronts. However, two samples located at the intermediate depths of the profile yield ages comparable with those

  7. Psychological distress among adolescents in Chengdu, Sichuan at 1 month after the 2008 Sichuan earthquake.

    PubMed

    Lau, Joseph T F; Yu, Xiaonan; Zhang, Jianxin; Mak, Winnie W S; Choi, Kai Chow; Lui, Wacy W S; Zhang, Jianxin; Chan, Emily Y Y

    2010-05-01

    A devastating earthquake occurred on May 12, 2008 in Sichuan, China. This study investigated the prevalence and factors in association with psychological problems among secondary school students living in Chengdu (90 km away from the disaster epicenter) in June 2008. In a cross-sectional survey, 3,324 secondary students self-administered a structured questionnaire in classroom setting. Validated scales were used in this study. Among all respondents, 22.3% reported post-traumatic stress disorder (PTSD); 22.6% were probable depression cases; 10.6% reported suicidal ideation; and 14.1% would like to receive psychological counseling. No gender differences were found. While social/emotional support from teachers or peers (OR from 0.40 to 0.78) and exposure to positive news reports (OR from 0.59 to 0.62) were found protective, prior experience of severe mental distress (OR from 1.60 to 2.68) and corporal punishment (OR from 1.31 to 1.58), worry about future aftershocks (OR from 1.64 to 3.11), absence from school when it was not closed (OR from 1.38 to 1.48), exposures to scary or sorrowful disaster media coverage (OR from 1.39 to 2.07), post-disaster visits to affected sites (OR from 1.51 to 1.59), separation from parents (OR = 1.61), etc., were risk factors predictive of some of the aforementioned psychological problems. Negative mental health impacts were prevalent among the respondents. Teachers, parents, and the mass media are all important in maintaining good mental health among adolescents that are indirectly affected by the severe earthquake. The results have important implications for earthquake preparedness and relief work in the future. PMID:20405226

  8. Multiphase origin of the Cu Co ore deposits in the western part of the Lufilian fold-and-thrust belt, Katanga (Democratic Republic of Congo)

    NASA Astrophysics Data System (ADS)

    Dewaele, S.; Muchez, Ph.; Vets, J.; Fernandez-Alonzo, M.; Tack, L.

    2006-12-01

    A multiphase origin of the Cu-Co ores in the western part of the Lufilian fold-and-thrust belt in Central Africa is proposed based on literature, satellite image interpretations and petrographic and fluid inclusion analyses on samples from the stratiform mineralization of Kamoto and Musonoi (DR Congo). The various mineral occurrences in the Katanga Copperbelt can be classified in distinct categories: stratiform, supergene enrichment and vein-type. The stratiform mineralization form the largest group and can be found mainly in Lower Roan (R-2) rocks, which can be identified as ridges on satellite imagery. Ore deposits outside the R-2 occur along lineaments and result often from supergene enrichment. The main phase of the stratiform mineralization in the Katanga Copperbelt occurred during diagenesis preceding the Lufilian orogeny. Petrographic observation identified various mineralizing phases, which played a role in the formation of these stratiform mineralization. Mineralization started during early diagenesis, but mainly occurred during further burial. After the formation of early diagenetic pyrite, the circulation of diagenetic Cu-Co-rich fluids resulted in the formation of the main mineralization. Preliminary microthermometric investigation of primary inclusions in authigenic quartz, associated with the main stage of stratiform mineralization, indicates that an H 2O-NaCl fluid with a minimum temperature between 80 and 195 °C and a salinity between 8.4 and 18.4 eq. wt% NaCl circulated during the main phase of mineralization. Numerous faults and fractures formed during the Lufilian orogeny cut the stratiform mineralization. They are, however, at Kamoto and Musonoi only associated with minor sulphides. Supergene alteration along faults and fractures resulted in an enrichment of the mineralization, with the formation of secondary Cu-oxides, -carbonates and -silicates. The importance of the interaction of various processes for the formation of economic Cu-Co ore

  9. Hydrothermal remobilisation around a deformed and remobilised komatiite-hosted Ni-Cu-(PGE) deposit, Sarah's Find, Agnew Wiluna greenstone belt, Yilgarn Craton, Western Australia

    NASA Astrophysics Data System (ADS)

    Le Vaillant, Margaux; Saleem, Ahmad; Barnes, Stephen J.; Fiorentini, Marco L.; Miller, John; Beresford, Steve; Perring, Caroline

    2016-03-01

    The Sarah's Find nickel deposit, located 4.5 km north of the Mount Keith nickel mine, Western Australia, was chosen as a case study to investigate the nature and three-dimensional geometry of a geochemical halo created by the hydrothermal remobilisation of base metals and platinum group elements into the country rock surrounding a small massive Ni sulphide orebody. Portable and laboratory-based XRF analyses were carried out on samples from a shear zone localised along the basal komatiite-dacite contact that hosts the orebody. A geochemical halo was identified that extends along the shear zone up to 1780 m away from the massive sulphides, parallel to a prominent stretching lineation. Elevated Ni and Pd are associated with high As, Co, Cu and S. Palladium and Pt concentrations increase with proximity to massive sulphides (from 6 to 1190 ppb Pd). These anomalous concentrations reflect the presence of sulfarsenides and sulphides, either physically remobilised and forming veinlets close to the massive sulphides, or hydrothermally transported and redeposited within the foliation. In situ laser ablation ICP-MS indicates that Pd and Pt are hosted within these nickel sulfarsenides. This Ni-Co-As-Pd geochemical halo, observed around the Sarah's Find ore body, is interpreted as forming syn deformation, by the circulation of As-rich hydrothermal fluids dissolving base metals, Pd and Pt from the orebody and redepositing them along the sheared footwall contact. Similar Ni-Co-Pd-Pt-As geochemical haloes could potentially exist around any magmatic nickel sulphide mineral system that has undergone a phase of arsenic metasomatism and may be a generally applicable proximity indicator for nickel sulphides in hydrothermally altered terranes.

  10. Three dimensional surface displacement of the Sichuan earthquake (Mw 7.9, China) from Synthetic Aperture Radar.

    NASA Astrophysics Data System (ADS)

    de Michele, Marcello; Raucoules, Daniel; de Sigoyer, Julia; Pubellier, Manuel; Lasserre, Cecile; Pathier, Erwan; Klinger, Yann; van der Woerd, Jerome; Chamot-Rooke, Nicolas

    2010-05-01

    The Sichuan earthquake, Mw 7.9, struck the Longmen Shan range front, in the western Sichuan province, China, on 12 May 2008. It severely affected an area where little historical seismicity and little or no significant active shortening were reported before the earthquake (e.g. Gu et al., 1989; Chen et al., 1994; Gan et al., 2007). The Longmen Shan thrust system bounds the eastern margin of the Tibetan plateau and is considered as a transpressive zone since Triassic time that was reactivated during the India-Asia collision (e.g., Tapponnier and Molnar, 1977, Chen and Wilson 1996; Arne et al., 1997, Godard et al., 2009). However, contrasting geological evidences of sparse thrusting and marked dextral strike-slip faulting during the Quaternary along with high topography (Burchfiel et al., 1995; Densmore et al., 2007) have led to models of dynamically driven and sustained topography (Royden et al., 1997) limiting the role of earthquakes in relief building and leaving the mechanism of long term strain distribution in this area as an open question. Here we combine C and L band Synthetic Aperture Radar (SAR) offsets data from ascending and descending paths to retrieve the three dimensional surface displacement distribution all along the earthquake ruptures of the Sichuan earthquake. For the first time on this earthquake we present near field 3D co-seismic surface displacement, which is an important datum for constraining modelled fault geometry at depth. Our results complement other Interferometric Synthetic Aperture Radar (InSAR) and field analyses in indicating that crustal shortening is one of the main drivers for topography building in the Longmen Shan (Liu-Zeng, 2009; Shen et al., 2009; Hubbard and Shaw, 2009). Moreover, our results put into evidence a small but significant amount of displacement in the range front that we interpret as due to slip at depth on a blind structure. We verify this hypothesis by inverting the data against a simple elastic dislocation model

  11. Silver-rich telluride mineralization at Mount Charlotte and Au-Ag zonation in the giant Golden Mile deposit, Kalgoorlie, Western Australia

    NASA Astrophysics Data System (ADS)

    Mueller, Andreas G.; Muhling, Janet R.

    2013-03-01

    The gold deposits at Kalgoorlie in the 2.7-Ga Eastern Goldfields Province of the Yilgarn Craton, Western Australia, occur adjacent to the D2 Golden Mile Fault over a strike of 8 km within a district-scale zone marked by porphyry dykes and chloritic alteration. The late Golden Pike Fault separates the older (D2) shear zone system of the Golden Mile (1,500 t Au) in the southeast from the younger (D4) quartz vein stockworks at Mt Charlotte (126 t Au) in the northwest. Both deposits occur in the Golden Mile Dolerite sill and display inner sericite-ankerite alteration and early-stage gold-pyrite mineralization replacing the wall rocks. Late-stage tellurides account for 20 % of the total gold in the first, but for <1 % in the second deposit. In the Golden Mile, the main telluride assemblage is coloradoite + native gold (898-972 fine) + calaverite + petzite ± krennerite. Telluride-rich ore (>30 g/t Au) is characterized by Au/Ag = 2.54 and As/Sb = 2.6-30, the latter ratio caused by arsenical pyrite. Golden Mile-type D2 lodes occur northwest of the Golden Pike Fault, but the Hidden Secret orebody, the only telluride bonanza mined (10,815 t at 44 g/t Au), was unusually rich in silver (Au/Ag = 0.12-0.35) due to abundant hessite. We describe another array of silver-rich D2 shear zones which are part of the Golden Mile Fault exposed on the Mt Charlotte mine 22 level. They are filled with crack-seal and pinch-and-swell quartz-carbonate veins and are surrounded by early-stage pyrite + pyrrhotite disseminated in a sericite-ankerite zone more than 6 m wide. Gold grade (0.5-0.8 g/t) varies little across the zone, but Au/Ag (0.37-2.40) and As/Sb (1.54-13.9) increase away from the veins. Late-stage telluride mineralization (23 g/t Au) sampled in one vein has a much lower Au/Ag (0.13) and As/Sb (0.48) and comprises scheelite, pyrite, native gold (830-854 fine), hessite, and minor pyrrhotite, altaite, bournonite, and boulangerite. Assuming 250-300 °C, gold-hessite compositions

  12. Passion: Burning in the West--An Investigation on College Students' Volunteer Teaching in Western China

    ERIC Educational Resources Information Center

    Zhen, Li

    2008-01-01

    In this article, the author investigates college students' volunteer teaching in Western China. A series of investigations were conducted in Chongqing, Sichuan, Guizhou, Yunnan, Shanxi, Gansu, Qinghai, Ningxia, and Xinjiang. The results showed that teaching by volunteer college students played a positive role in the development of local education…

  13. Excavating the Nation: Archaeology and Control of the Past and Present in Republican Sichuan

    ERIC Educational Resources Information Center

    Kyong-McClain, Jeffrey

    2009-01-01

    This dissertation considers whether or not archaeology was an effective tool for nation-building elites in Republican China (1912-1949), by looking at the discipline's fortunes in the off-center locale of Sichuan province. Through consideration of the multiplicity of agents and motives involved in archaeological enterprise in Republican Sichuan,…

  14. Characterization of magnetic spherical fractions in sand deposits for interpretation of environmental change around the El- Zayyan temple, Kharga Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Watanabe, Makiko; Koizumi, Natsuko; Kato, Sayuri; Kikuchi, Ryohei; Kamei, Hiroyuki

    2014-05-01

    Desertification in North Africa has rapidly advanced over the last 6,000 years. Such environmental changes began in the Early Dynastic Period of Egypt (4200 - 3150 BC), and the occupation of Achaemenid Persian and Roman cultures in Egypt occurred under even drier climates. Kharga is the largest oasis of the five oases, located in the western desert of Egypt that contains a treasure trove of archaeological resources. This oasis has been highlighted to promote resource exploration and development of archaeological tourism since the 1980's. The El-Zayyan temple is located 27 km south of the central Kharga oasis. Zayyan was once called 'Tchonemyris', which has connection with the means of 'huge well' in Greek. Although major portions of the temple were rebuilt in 140 AD during the rule of the Roman Emperor Antoninus Pius, this temple is considered to be originally built in the Ptolemaic period (4c-1c BC). It is likely that the area had a sufficient water supply in the past as the El-Zayyan temple stands at the lowest point (-18 m a.s.l.) in the Kharga oasis. Furthermore, the El-Ghueita temple that stands on a hill top at 68.5 m a.s.l., 4 km northward from the El-Zayyan temple, has given name that means 'beautiful garden' in Greek. From these facts, we can imagine that the past landscape of this area contained green surroundings. The El-Ghueita temple was well known as a production centre of high quality wine since the mid-Dynastic age (2050 -1786 BC). As this area is currently arid, it is expected that there were irrigation facilities to maintain the vast farm land during the ancient period. To deepen our knowledge of how people developed their technologies and conducted their life within the natural environment of a drastic drying period, understanding the process of environmental change on a region scale is necessary. The aim of this study was to extract proxies from sand deposits in the western desert area to estimate the change in the environment. We examined the

  15. 40Ar/39Ar and (U-Th)/He - 4He/3He geochronology of landscape evolution and channel iron deposit genesis at Lynn Peak, Western Australia

    NASA Astrophysics Data System (ADS)

    Vasconcelos, Paulo M.; Heim, Jonathan A.; Farley, Kenneth A.; Monteiro, Hevelyn; Waltenberg, Kathryn

    2013-09-01

    (U-Th)/He geochronology of authigenic goethite cements from the Lynn Peak channel iron deposit (CID), Hamersley Province, Western Australia, reveals a history of mineral precipitation ranging from ca. 33 to 14 Ma. Massive goethites from nearby weathering profiles at Roy Hill North, a possible source of detrital material during the aggradation of the Lynn Peak channels, yield (U-Th)/He results as old as ca. 64 Ma. The combination of (U-Th)/He geochronology with incremental outgassing 4He/3He studies on proton-irradiated samples reveals that Lynn Peak goethites host radiogenic 4He in low retentivity (LRD) and high retentivity (HRD) domains and that the HRDs account for most of the sample mass and have lost very little of their original 4He over geologic time. Such high retentivity is especially notable given the goethites were collected from the surface, where they were subject to significant heating by solar irradiation. Minor contamination by detrital fragments of potentially 4He-rich primary phases (e.g., rutile, ilmenite, zircon) occurs in some samples. Fortunately, the 4He/3He method permits characterization of this extraneous 4He component, which is small (<10 wt.% of the total 4He in the goethite) and can be corrected out in estimating the goethite formation age. These results indicate that the Lynn Peak channel was already aggraded and undergoing goethite cementation by ca. 33 Ma. The history of aggradation and channel cementation independently measured through 40Ar/39Ar geochronology is consistent with that obtained from the (U-Th)/He and 4He/3He record. Laser incremental-heating 40Ar/39Ar geochronology of detrital and authigenic Mn oxides, primarily cryptomelane (KMn8O16·xH2O), from the same locality in the Lynn Peak channel reveals that detrital oxides are older than ca. 44 Ma (and as old as ca. 65 Ma) and authigenic oxides are younger than ca. 35 Ma and as young as ca. 16 Ma. Authigenic cryptomelane precipitation and channel cementation occurred

  16. Leaching of silica bands and concentration of magnetite in Archean BIF by hypogene fluids: Beebyn Fe ore deposit, Yilgarn Craton, Western Australia

    NASA Astrophysics Data System (ADS)

    Duuring, Paul; Hagemann, Steffen

    2013-03-01

    The ~2,752-Ma Weld Range greenstone belt in the Yilgarn Craton of Western Australia hosts several Fe ore deposits that provide insights into the role of early hypogene fluids in the formation of high-grade (>55 wt% Fe) magnetite-rich ore in banded iron formation (BIF). The 1.5-km-long Beebyn orebody comprises a series of steeply dipping, discontinuous, <50-m-thick lenses of magnetite-(martite)-rich ore zones in BIF that extend from surface to vertical depths of at least 250 m. The ore zones are enveloped by a 3-km-long, 150-m-wide outer halo of hypogene siderite and ferroan dolomite in BIF and mafic igneous country rocks. Ferroan chlorite characterises 20-m-wide proximal alteration zones in mafic country rocks. The magnetite-rich Beebyn orebody is primarily the product of hypogene fluids that circulated through reverse shear zones during the formation of an Archean isoclinal fold-and-thrust belt. Two discrete stages of hypogene fluid flow caused the pseudomorphic replacement of silica-rich bands in BIF by Stage 1 siderite and magnetite and later by Stage 2 ferroan dolomite. The resulting carbonate-altered BIF is markedly depleted in SiO2 and enriched in CaO, MgO, LOI, P2O5 and Fe2O3(total) compared with the least-altered BIF. Subsequent reactivation of these shear zones and circulation of hypogene fluids resulted in the leaching of existing hypogene carbonate minerals and the concentration of residual magnetite-rich bands. These Stage 3 magnetite-rich ore zones are depleted in SiO2 and enriched in K2O, CaO, MgO, P2O5 and Fe2O3(total) relative to the least-altered BIF. Proximal wall rock hypogene alteration zones in mafic igneous country rocks (up to 20 m from the BIF contact) are depleted in SiO2, CaO, Na2O, and K2O and are enriched in Fe2O3(total), MgO and P2O5 compared with distal zones. Recent supergene alteration affects all rocks within about 100 m below the present surface, disturbing hypogene mineral and the geochemical zonation patterns associated with

  17. Magnetostratigraphy of the Permo-Triassic boundary section at Shangsi (Guangyuan, Sichuan Province, China)

    NASA Astrophysics Data System (ADS)

    Heller, Friedrich; Lowrie, William; Huamei, Li; Junda, Wang

    1988-05-01

    Continous marine sedimentation characterizes many Late Permian to Early Triassic sections on the Yangtze terrane in South China. The Permo-Triassic (P/Tr) boundary section at Shangsi (Sichuan Province) consists of limestones intercalated with clays and mudstones which belong to the Wuchiapingian and Changxingian (Upper Permian) and the Griesbachian and Dienerian (Lower Triassic) stages. The P/Tr boundary is formed by a clay horizon with an unusually high iridium concentration. The intensity of natural remanent magnetization is very low with a mean of 0.15 mA m -1. About 40% of the samples contain secondary or unstable magnetization components only, whereas the remaining samples carry a characteristic remanent magnetization thought to reflect the polarity of the geomagnetic field during deposition with sufficient accuracy. Normal and reversed polarity of the characteristic magnetization constitute a pattern of at least six polarity zones, the P/Tr boundary being situated very close to the transition from a reversed to a normal polarity zone. The Shangsi polarity sequence represents part of the Illawarra interval of mixed polarity, the exact beginning of which has still to be determined.

  18. Dry deposition washoff and dew on the surfaces of pine foliage on the urban- and mountain-facing sides of Mt. Gokurakuji, western Japan

    NASA Astrophysics Data System (ADS)

    Chiwa, M.; Oshiro, N.; Miyake, T.; Nakatani, N.; Kimura, N.; Yuhara, T.; Hashimoto, N.; Sakugawa, H.

    Dry deposition and dew components on pine foliage were measured from 1998 to 2000 on the urban- and mountain-facing sides of Mt. Gokurakuji in order to estimate the effect of anthropogenic activities to dry deposition and dew concentration on the surfaces of pine foliage. A leaf wash experiment was employed to determine the dry deposition rates on the pine foliage. The NO 3- and SO 42- dry deposition rates per unit surface area of pine foliage were 1.47 and 0.28 μmol m -2 h -1 respectively on the urban-facing side and 0.32 and 0.09 μmol m -2 h -1 on the mountain-facing side. Dry deposition fluxes of N (NO 3-+NH 4+) and S (SO 42-) to the forest floors were 8.4 kg N ha -1 yr -1 and 2.8 kg S ha -1 yr -1 on the urban-facing, and 3.3 kg N ha -1 yr -1 and 1.8 kg S ha -1 yr -1 on the mountain-facing side, respectively. The higher dry deposition fluxes of N and S on the urban-facing side could be attributed to its proximity to traffic roads and the urban area. The concentrations of most ions in the dew were higher on the urban-facing side (U130) than on the mountain-facing side (M430). NO 3- and SO 42- concentrations in dew at U130 were 802 and 428 μeq l -1, respectively, while at M430 they were 199 and 222 μeq l -1, respectively, suggesting that higher dry deposition rates on the urban-facing side enhanced their concentrations in the dew on this side. The role of dry deposits and subsequently dissolved ones in dew on the needle surfaces is discussed in terms of pine tree damage by atmospheric depositions.

  19. Structural, mineralogical and geochemical constraints on the atypical komatiite-hosted Turret deposit in the Agnew-Mt. White district, Western Australia

    NASA Astrophysics Data System (ADS)

    Voute, F.; Thébaud, N.

    2015-08-01

    In the Norseman-Wiluna belt, Yilgarn Craton, the Agnew-Mt. White district is the host of many gold deposits. Located in the hinge of the regional Lawlers anticline, the Turret gold deposit is structurally controlled by the Table Hill shear zone that transects the Agnew Ultramafic unit. Geochemistry, coupled with petrographic data, allowed the delineation of the paragenetic sequence associated with gold mineralisation and include (1) a pervasive talc-carbonate alteration assemblage, (2) a pre-mineralisation stage associated with pervasive arsenopyrite + chalcopyrite + pyrrhotite + pyrite alteration, followed by (3) a late deformation event along a dilatational segment of the main Table Hill shear zone, leading to the formation of a breccia hosting a Cu-Bi-Mo-Au (± Ag ± Zn ± Te ± W) metal assemblage. The presence of Au-Ag-Cu alloys, native bismuth, chalcopyrite and other Bi-Te-S phases in the mineralisation stage suggest that gold may have been scavenged from the hydrothermal fluids by composite Bi-Te-Cu-Au-Ag-S liquids or melts. Using this mineral paragenetic sequence, together with mineralogical re-equilibration textures observed, we show that the gold deposition at Turret occurred over a temperature range approximately between c. 350 and 270 °C. This temperature range, together with the structural control and typical mesothermal alteration pattern including carbonate-chlorite alteration, shows that the Turret deposit shares common characteristics with the orogenic gold deposit class. However, the metal association of Cu, Au, Bi, and Mo, the quartz-poor, and high copper-sulphide content (up to 15 %) are characteristics that depart from the typical orogenic gold deposit mineralogy. Through comparison with similar deposits in the Yilgarn Craton and worldwide, we propose that the Turret deposit represents an example of a porphyry-derived Au-Cu-Bi-Mo deposit.

  20. Late-kinematic timing of orogenic gold deposits and significance for computer-based exploration techniques with emphasis on the Yilgarn Block, Western Australia

    USGS Publications Warehouse

    Groves, D.I.; Goldfarb, R.J.; Knox-Robinson, C. M.; Ojala, J.; Gardoll, S.; Yun, G.Y.; Holyland, P.

    2000-01-01

    Orogenic gold deposits are a widespread coherent group of epigenetic ore deposits that are sited in accretionary or collisional orogens. They formed over a large crustal-depth range from deep-seated low-salinity H2O-CO2 + CH4 + N2 ore fluids and with Au transported as thio-complexes. Regional structures provide the main control on deposit distribution. In many terranes, first-order faults or shear zones appear to have controlled regional fluid flow, with greatest ore-fluid fluxes in, and adjacent to, lower-order faults, shear zones and/or large folds. Highly competent and/or chemically reactive rocks are the most common hosts to the larger deposits. Focusing of supralithostatic ore fluids into dilatant zones appears to occur late during the evolutionary history of the host terranes, normally within D3 or D4 in a D1-D4 deformation sequence. Reactivation of suitably oriented pre-existing structures during a change in far-field stress orientation is a factor common to many deposits, and repeated reactivation may account for multiple mineralization episodes in some larger deposits. Absolute robust ages of mineralization support their late-kinematic timing, and, in general, suggest that deposits formed diachronously towards the end of the 100 to 200 m.y. long evolutionary history of hosting orogens. For example, in the Yilgarn Block, a region specifically emphasised in this study, orogenic gold deposits formed in the time interval between 40 and 90 m.y., with most about 60 to 70 m.y., after the youngest widespread basic-ultrabasic volcanism and towards the end of felsic magmatism. The late timing of orogenic gold deposits is pivotal to geologically-based exploration methodologies. This is because the present structural geometries of: (i) the deposits, (ii) the hosting goldfields, and (iii) the enclosing terranes are all essentially similar to those during gold mineralization, at least in their relative position to each other. Thus, interpretation of geological maps and

  1. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  2. Late Miocene termination of tectonic activity on the detachment in the Alaşehir Rift, Western Anatolia: Depositional records of the Göbekli Formation and high-angle cross-cutting faults

    NASA Astrophysics Data System (ADS)

    Sen, Fatih

    2016-04-01

    Western Anatolia is a well-known province of continental extension in the world. Most distinctive structural elements of the region are E-W trending grabens. The Alaşehir Rift/Graben is an asymmetric rift/graben trending E-W between Ahmetli and Turgutlu in its western part and continues eastwardly in a NW-SE direction to Alaşehir (Philadelphia in ancient Greek). The stratigraphy of the region consists of metamorphic rocks of the Menderes Massif (Paleozoic-lower Cenozoic) and the syn-extensional Salihli granitoid (middle Miocene) forming the basement unit and overlying sedimentary cover rocks of Neogene-Quaternary. These rocks are cut and deformed by the Karadut detachment fault and various low-angle normal faults (antithetic and synthetic faults of the Karadut detachment fault), which are also cut by various younger high-angle normal faults. It is possible to observe two continuous sequences of different time intervals in that Miocene deposits of the first rifting phase are covered by Plio-Quaternary sediments of second rifting phase with a "break-up" unconformity. In lower levels of a measured stratigraphic section (583 m) of the Göbekli formation which has lower age of late Miocene and upper age of early Pliocene, the presence of angular to sub-angular clasts of the blocks and conglomerates suggests alluvial-fun origin during an initial stage of deposition. Existence of normal-reverse graded, cross-bedding, pebble imbrications in layers of the pebbly sandstone demonstrates fluvial environment in following levels of the sequence. Existence of lenses and normal graded conglomerates in pebbly sandstones and fine grained sandstones strata evidences a low energy environment. Observed siltstone-claystone intercalations on the middle levels of the sequence indicate an environment with low dipping morphology to be formed as flat plains during this period. In the uppermost levels of the sequence, existence of the pebble imbrications inside pebbly sandstones overlying

  3. Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

    NASA Astrophysics Data System (ADS)

    Xing, Xinli; Zhang, Yuan; Yang, Dan; Zhang, Jiaquan; Chen, Wei; Wu, Chenxi; Liu, Hongxia; Qi, Shihua

    2016-08-01

    Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m-2 yr-1 to 978.58 μg m-2 yr-1 with geometric mean of 354.22 μg m-2 yr-1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p < 0.05) between annual atmospheric bulk deposition and local PAHs emission, with biomass burning as the major contribution to the total emission of PAHs. This transect acts as an important PAHs source rather than being a sink according to the ratio of deposition/emission. Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only

  4. Atmospheric deposition of SO 4-S and (NH 4+NO 3)-N at two rural sites in the Western Maracaibo Lake Basin, Venezuela

    NASA Astrophysics Data System (ADS)

    Morales, Jose Agustin; Bifano, Claudio; Escalona, Andres

    Rain samples were collected by events from November 1988 to November 1989 at La Esperanza and Catatumbo sites. Dry deposition was collected only at La Esperanza. Volume weighted average pH values of the rainfall samples were between 4.23 and 4.64, individual samples reaching as low as pH 3.0. An excess of sulfate greater than 96% was obtained at both sites. The wet deposition of hydronium and sulfate showed the same seasonal cycle. The highest inputs were obtained in April during the early rainy season, and November which is the second peak rainfall period. The amounts of (NH 4+NO 3)-N ha -1 yr -1 added by wet deposition ranged from 5.2 kg at La Esperanza to 11.4 kg at Catatumbo (ammonium accounts for about 67% of these amounts), and the corresponding amounts of SO 4-S deposited ranged from 10.5 to 12.5 kg, respectively. These amounts of S and N annually deposited by precipitation are substantially higher than those found in eastern Venezuelan sites, and slightly lower than the values reported for rural areas of Europe and North America. In La Esperanza it was estimated that wet deposition accounts for about 93% of the inorganic-N and for about 80% of the SO 4-S annually added by dry and wet deposition. It is envisaged that in Lake Maracaibo Basin large argricultural and uncultivated land areas downwind of the El Tablazo Petrochemical Complex, Cardon-Amuay and, probably, the Aruba-Curacao refineries and urban Maracaibo might already be affected by anthropogenic air pollution as evidenced by the higher level of H +, SO -24, NO -3 and NH +4 wet deposition found at the La Esperanza and Catatumbo sites in comparison with other rural sites in Venezuela.

  5. Assessment of Paleozoic shale gas resources in the Sichuan Basin of China, 2015

    USGS Publications Warehouse

    Potter, Christopher J.; Schenk, Christopher J.; Charpentier, Ronald R.; Gaswirth, Stephanie B.; Klett, Timothy R.; Leathers, Heidi M.; Brownfield, Michael E.; Mercier, Tracey J.; Tennyson, Marilyn E.; Pitman, Janet K.

    2015-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 23.9 trillion cubic feet of technically recoverable shale gas resources in Paleozoic formations in the Sichuan Basin of China.

  6. Streptococcus suis sequence type 7 outbreak, Sichuan, China.

    PubMed

    Ye, Changyun; Zhu, Xiaoping; Jing, Huaiqi; Du, Huamao; Segura, Mariela; Zheng, Han; Kan, Biao; Wang, Lili; Bai, Xuemei; Zhou, Yongyun; Cui, Zhigang; Zhang, Shouying; Jin, Dong; Sun, Na; Luo, Xia; Zhang, Ji; Gong, Zhaolong; Wang, Xin; Wang, Lei; Sun, Hui; Li, Zhenjun; Sun, Qiangzheng; Liu, Honglu; Dong, Boqing; Ke, Changwen; Yuan, Hui; Wang, Hua; Tian, Kecheng; Wang, Yu; Gottschalk, Marcelo; Xu, Jianguo

    2006-08-01

    An outbreak of Streptococcus suis serotype 2 emerged in the summer of 2005 in Sichuan Province, and sporadic infections occurred in 4 additional provinces of China. In total, 99 S. suis strains were isolated and analyzed in this study: 88 isolates from human patients and 11 from diseased pigs. We defined 98 of 99 isolates as pulse type I by using pulsed-field gel electrophoresis analysis of SmaI-digested chromosomal DNA. Furthermore, multilocus sequence typing classified 97 of 98 members of the pulse type I in the same sequence type (ST), ST-7. Isolates of ST-7 were more toxic to peripheral blood mononuclear cells than ST-1 strains. S. suis ST-7, the causative agent, was a single-locus variant of ST-1 with increased virulence. These findings strongly suggest that ST-7 is an emerging, highly virulent S. suis clone that caused the largest S. suis outbreak ever described. PMID:16965698

  7. Physicomechanical parameters of sedimentary rocks in eastern Sichuan, China

    NASA Astrophysics Data System (ADS)

    Guo, Jian; Sun, Yan; Shu, Liangshu; Zhu, Wenbin; Liu, Deliang; Wang, Feng; Li, Benliang

    2009-12-01

    Rock samples were collected and selected from the sedimentary covering strata from Cambrian to Jurassic in eastern Sichuan, China, which belongs to the Upper Yangtze plate. Physicomechanical parameters were measured systematically. Based on parametric texture characteristics and observation data of geology, five regional layer-slip systems are derived. The five layer-slip systems correspond to five reservoir-cover systems, as the incompetent beds correspond to cover beds and the competent beds to reservoir beds. In comparison with the Middle and Lower Yangtze plates, the physicomechanical parameters, lithologic composition and structural characteristics are basically similar to the Upper Yangtze plate. This comparison offers some insight into the oil and gas reservoir-cover systems in the region.

  8. Landslide erosion associated with the May 12, 2008 Sichuan Earthquake

    NASA Astrophysics Data System (ADS)

    Ouimet, W.

    2008-12-01

    The M7.9 earthquake of May 12, 2008 in Sichuan, China triggered a remarkable number of landslides. As time progresses and satellite imagery becomes available, the landslide inventory associated with this event will be a valuable dataset for understanding the dynamics and distribution of landslides triggered by large earthquakes and for constraining models of landscape evolution in steep topography where landslides are the dominant mode of hillslope erosion. The landslides associated with Sichuan earthquake will also have interesting implications for the tectonic and landscape evolution of the Longmen Shan. Preliminary analysis of satellite imagery reveals that the highest density of landslides and therefore the greatest amount of landslide driven erosion was focused along Longmen Shan front associated with steep, high relief topography and is closely tied to the region of greatest ground motion in the hanging wall of the fault rupture. The rocks underlying the highest density of landslides are Precambrian granites and gneisses, and landslide density decreases moving to the northeast in areas underlain by deformed Paleozoic sediments. Short-term erosion rates in the Longmen Shan region measured prior to the earthquake from concentrations of 10Be in quartz extracted in 5 river catchments were 0.22-0.32 mm/yr, reflecting the last 1,500-3,000 years - a time period shorter than the estimated recurrence interval of large earthquakes along the fault that ruptured. Long-term erosion rates measured by low-temperature thermochronology, meanwhile, are higher, 0.5-0.6 mm/yr (Kirby et al., 2002). This suggests that the earthquake and landslide erosion associated with it allowed the landscape to catch up and balance the tectonic growth of Longmen Shan.

  9. Characterization of depositional age and structure of sedimentary successions by U-Pb TIMS and LA-ICP-MS dating of volcanic horizons and detrital zircons: an example from the western Trondheim Nappe Complex, Scandinavian Caledonides

    NASA Astrophysics Data System (ADS)

    Gasser, Deta; Grenne, Tor; Corfu, Fernando; Eivind Augland, Lars

    2016-04-01

    Revealing the absolute depositional age of non-fossiliferous sedimentary successions represents a long-lasting challenge in Earth Sciences. Lacking age control hampers the correct interpretation of the temporal evolution of depositional systems, and, if deformed, of the architecture of fold-and-thrust belts. Dating of detrital zircons within clastic sedimentary successions has over the past decades become a popular method to approximate the absolute depositional age and to characterize the source areas of such rocks. If combined with other geochronological information, such as dating of contemporaneous volcanic horizons, a much better resolution of the stratigraphy and structure of non-fossiliferous sedimentary successions can be achieved. The western Trondheim nappe complex in the central Scandinavian Caledonides is a classical area in this respect. On top of Late Cambrian to Early Ordovician ophiolitic fragments, various volcanic, volcano-clastic and clastic successions tell a complex story of island-arc formation, ocean closure and continent collision. Several famous fossil horizons indicate deposition during the Middle to Upper Ordovician (ca. 470-445 Ma), but large areas lack an absolute age control and several contrasting stratigraphic schemes and structural interpretations have been presented in the past. In this contribution we present the results of LA-ICP-MS detrital U-Pb zircon dating of clastic horizons as well as U-Pb TIMS zircon dating of volcanic horizons and magmatic clasts in conglomerates in order to characterize the depositional age and structure of the western Trondheim nappe complex in more detail. Together with field observations, including way up criteria, the zircon data enable significant revisions of existing stratigraphic and structural models. At least four (volcano-)sedimentary successions can be distinguished above the ca. 480-485 Ma greenstones: (1) ca. 470-463 Ma shales, limestones and andesitic porphyrites (Hølonda and Fanabekken

  10. Microgranular enclaves in island-arc andesites: A possible link between known epithermal Au and potential porphyry Cu-Au deposits in the Tulasu ore cluster, western Tianshan, Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaobo; Xue, Chunji; Symons, David T. A.; Zhang, Zhaochong; Wang, Honggang

    2014-05-01

    The successful exploration for porphyry copper deposit in western Tianshan, Xinjiang, faces great challenge. Tulasu basin is an important epithermal gold ore cluster in western Tianshan, which was formed in a southwest-Pacific-type island-arc setting during the late Paleozoic by the southward subduction of the North Tianshan ocean beneath the Yili plate. Porphyry Cu-Au deposits are possibly to be found at depth or adjacent to these epithermal gold deposits. Some sulfide-mineralized microgranular enclaves of monzonite porphyry and microdiorite were found in andesites of the Tawuerbieke gold district, Tulasu basin. The enclaves are randomly distributed, with generally round or subangular shape and commonly clearly defined within their host andesite, and have a chilled surrounding margin of andesite. The monzonite porphyry enclaves (MPE) exhibit porphyritic texture with the phenocrysts of plagioclase and K-feldspar. The microdiorite enclaves (MDE) are mainly composed of plagioclase and hornblende with an aplitic texture and massive structure. The host andesites show porphyritic texture, with the phenocrysts major of plagioclase, minor of hornblende and clinopyroxene. The groundmass consists of short-column plagioclase and minor clinopyroxene with a hyalopilitic texture. Zircon grains from a MPE sample yield a weighted 206Pb/238U age of 356.2 ± 4.3 Ma (n = 13, MSWD = 1.11), which is effectively coincident with the 360.5 ± 3.4 Ma (n = 20, MSWD = 0.61) of an andesite sample within analytical error, indicating that they were coeval. In addition, the MPE, MDE and the andesite samples share similar normalized incompatible element and rare earth element patterns that are characterized by a pronounced enrichment of large ion lithophile elements and a deficit of high field strength elements. Moreover, the samples show similar Nd isotope compositions to the contemporary andesites and basaltic andesites. Detailed petrology, geochronology and geochemistry studies suggest that

  11. Structural evolution of the Mount Wall region in the Hamersley province, Western Australia and its control on hydrothermal alteration and formation of high-grade iron deposits

    NASA Astrophysics Data System (ADS)

    Dalstra, Hilke J.

    2014-10-01

    The discovery of two relatively small but high-grade iron ore deposits near Mt Wall, an intensely faulted part of the southwestern Hamersley province provides unique insights into the structural control on ore formation in this region. The deposits have many geological features typical of the high grade microplaty hematite group which also contains the much larger Mt Tom Price, Paraburdoo and Mt Whaleback deposits. The deposits are structurally controlled along early normal faults and contain abundant microplaty hematite and martite, and are largely confined to the Dales Gorge member of the Brockman Iron Formation. In addition to the microplaty hematite-martite ore, there are martite-goethite ores and rare magnetite-goethite or magnetite-hematite ores. Below the modern weathering surface, hydrothermally altered zones in wallrock BIF from the Lower Dales Gorge member contain magnetite, hematite and carbonate/talc bearing mineral assemblages. A staged ore genesis model involving early extension and fluid circulation along normal faults, hypogene silica leaching and carbonate alteration, followed by deep meteoric oxidation with microplaty hematite formation and finally weathering can explain most features of the Mt Wall deposits. The role of deformation was to provide pathways for mineralising fluids and initiate the seed points for the mineralised systems. High grade iron in the Wellthandalthaluna deposit is situated between the NW to NNW trending Boolgeeda Creek fault and a synthetic joining splay, the Northern fault. Both are high angle normal faults and formed during early extension in this part of the province. Faults are characterised by localised small scale deformation and brecciation, deep carbonate alteration and oxidation. Recent weathering has penetrated deeply into the fault zones, converting the carbonate-rich assemblages into goethite. Mineralisation in the Arochar deposit is situated in the overlap or relay zone between two segments of the Mt Wall

  12. Age constraints on Jerritt Canyon and other Carlin-type gold deposits in the western United States-relationship to mid-Tertiary extension and magmatism

    USGS Publications Warehouse

    Hofstra, A.H.; Snee, L.W.; Rye, R.O.; Folger, H.W.; Phinisey, J.D.; Loranger, R.J.; Dahl, A.R.; Naeser, C.W.; Stein, H.J.; Lewchuk, M.

    1999-01-01

    Carlin-type gold deposits are difficult to date and a wide range of ages has been reported for individual deposits. Therefore, several methods were employed to constrain the age of the gold deposits in the Jerritt Canyon district. Dated igneous rocks with well-documented crosscutting relationships to ore provided the most reliable constraints. K/Ar and 40Ar/39Ar dates on igneous rocks are as follows: andesite dikes 324 Ma, sericitic alteration in andesite dikes 118 Ma, basalt dikes 40.8 Ma, quartz monzonite dikes 39.2 Ma, and calc-alkaline ignimbrites 43.1 to 40.1 Ma. Of these, only the andesite and basalt dikes are clearly altered and mineralized. The gold deposits are, therefore, younger than the 40.8 Ma basalt dikes. The sericitic alteration in the andesite dikes is unrelated to the gold deposits. A number of dating techniques did not work. K/Ar and 40Ar/39Ar dates on mica from mineralized Ordovician to Devonian sedimentary rocks gave misleading results. The youngest date of 149 Ma from the smallest <0.1-??m-size fraction shows that the temperature (120??-260??C) and duration (?) of hydrothermal activity was insufficient to reset preexisting fine-grained micas in the host rocks. The temperature and duration was also insufficient to anneal fission tracks in zircon from Ordovician quartzites as they yield Middle Proterozoic dates in both mineralized and barren samples. Apatites were too small for fission track dating. Hydrothermal sulfides have pronounced crustal osmium isotope signatures (187Os/188Os(initial) = 0.9-3.6) but did not yield a meaningful isochron due to very low Re and Os concentrations and large analytical uncertainties. Paleomagnetic dating techniques failed because the hydrothermal fluids sulfidized nearly all of the iron in the host rocks leaving no remnant magnetism. When published isotopic dates from other Carlin-type deposits in Nevada and Utah are subject to the rigorous evaluation developed for the Jerritt Canyon study, most deposits can be

  13. Nitrogen isotope chemostratigraphy across the Permian-Triassic boundary at Chaotian, Sichuan, South China

    NASA Astrophysics Data System (ADS)

    Saitoh, M.; Ueno, Y.; Nishizawa, M.; Isozaki, Y.; Takai, K.; Yao, J.; Ji, Z.

    2014-12-01

    Nitrogen isotopic compositions of upper Permian to lowermost Triassic rocks were analyzed at Chaotian, Sichuan, China, to clarify changes in the oceanic N cycle around the Permian-Triassic boundary (P-TB) including the entire Changhsingian (Late Late Permian) prior to the extinction. The analyzed ca. 40 m thick interval across the P-TB at Chaotian consists of three stratigraphic units: the upper Wujiaping Formation, the Dalong Formation, and the lowermost Feixianguan Formation, in ascending order. The upper Wujiaping Formation is composed of dark gray limestone with diverse shallow-marine fossils, such as calcareous algae, deposited on the shallow shelf. In contrast, the overlying Dalong Formation, ca. 25 m thick, is mainly composed of thinly bedded black mudstone and siliceous mudstone containing abundant radiolarians, deposited on the relatively deep slope/basin. Absence of bioturbation, substantially high TOC contents, and abundant occurrence of pyrite framboids in the Dalong Formation indicate deposition under anoxic conditions. The lowermost Feixianguan Formation is composed of thinly bedded gray marl and micritic limestone with minor fossils, deposited on the relatively shallow slope. δ15N values are in positive values around +1 to +2‰ in the upper Wujiaping Formation implying denitrification and/or anammox in the ocean. δ15N values gradually decrease to -1‰ in the lower Dalong Formation and are consistently low (around 0‰) in the middle Dalong to lowermost Feixianguan Formation. No clear δ15N shift is recognized across the extinction horizon. The consistently low δ15N values suggest the enhanced N fixation in the ocean during the Changhsingian at Chaotian. Composite profiles based on previous and the present studies demonstrate the substantial δ15N variation on a global scale in the late Permian to earliest Triassic; a systematic δ15N difference by low and high latitudes is particularly clarified. Although the enhanced N fixation throughout the

  14. Nitrogen isotope chemostratigraphy across the Permian-Triassic boundary at Chaotian, Sichuan, South China

    NASA Astrophysics Data System (ADS)

    Saitoh, Masafumi; Ueno, Yuichiro; Nishizawa, Manabu; Isozaki, Yukio; Takai, Ken; Yao, Jianxin; Ji, Zhansheng

    2014-10-01

    Nitrogen isotopic compositions of upper Permian to lowermost Triassic rocks were analyzed at Chaotian in northern Sichuan, South China, in order to clarify changes in the oceanic nitrogen cycle around the Permian-Triassic boundary (P-TB) including the entire Changhsingian (Late Late Permian) prior to the extinction. The analyzed ca. 40 m thick interval across the P-TB at Chaotian consists of three stratigraphic units: the upper Wujiaping Formation, the Dalong Formation, and the lowermost Feixianguan Formation, in ascending order. The upper Wujiaping Formation, ca. 10 m thick, is mainly composed of dark gray limestone with diverse shallow-marine fossils such as calcareous algae and brachiopods, deposited on the shallow shelf. In contrast, the overlying Dalong Formation, ca. 25 m thick, is mainly composed of thinly bedded black mudstone and siliceous mudstone containing abundant radiolarians, deposited on the relatively deep slope/basin. Absence of bioturbation, substantially high total organic carbon contents (up to 15%), and abundant occurrence of pyrite framboids in the main part of the Dalong Formation indicate deposition under anoxic condition. The lowermost Feixianguan Formation, ca. 5 m thick, is composed of thinly bedded gray marl and micritic limestone with minor fossils such as ammonoids and conodonts, deposited on the relatively shallow slope. δ15NTN values are in positive values around +1 to +2‰ in the upper Wujiaping Formation implying denitrification and/or anammox in the ocean. δ15NTN values gradually decrease to -1‰ in the lower Dalong Formation and are consistently low (around 0‰) in the middle Dalong to lowermost Feixianguan Formation. No clear δ15NTN shift is recognized across the extinction horizon. The consistently low δ15NTN values suggest the enhanced nitrogen fixation in the ocean during the Changhsingian at Chaotian. Composite profiles based on previous and the present studies demonstrate the substantial δ15N variation on a global

  15. Petrographic characterization of Kentucky coals. Final report. Part II. Depositional settings of the coal bearing, upper Tradewater Formation in western Kentucky with emphasis on the Mannington (No. 4) coal zone

    SciTech Connect

    Baynard, D.N.; Hower, J.C.

    1983-01-01

    Depositional settings were determined in the coal bearing, Middle Pennsylvanian, upper Tradewater Formation in western Kentucky with emphasis on the Mannington (No. 4) coal zone. The coals have been analyzed for maceral contents, lithotypes, dry sulfur/ash percentages, vitrinite reflectance values, pyrite/marcasite contents, and associated lithologies at different vertical and lateral scales. This study concludes that: (1) the thin coarsening - or fining upward sequences, under the Mannington (No. 4) coal zone are possibly shallow bayfill and channel-fill deposits that provided an environment that has slight differences in topography, (2) rapid vertical and lateral change in total vitrinite, dry sulfur/ash percentages and lithotypes at different scales in the Mannington (No. 4) coal zone are indicative of wideranging Eh and pH values and possibly result from slight changes in paleotopography, and (3) the Davis (No. 6) coal was deposited after a period of thick coarsening - or fining upward sequences, possibly providing a relatively flat-stable surface for peat development. The consistent total vitrinite, dry sulfur/ash values, and thickness trends indicate a more restricted environment (pH and Eh) in the Davis (No. 6) swamp. 41 references, 25 figures, 3 tables.

  16. Trace Element Determination from the Guliya Ice Core to Characterize Aerosol Deposition over the Western Tibetan Plateau during the Last 500 Years

    NASA Astrophysics Data System (ADS)

    Sierra Hernandez, R.; Gabrielli, P.; Beaudon, E.; Wegner, A.; Thompson, L. G.

    2014-12-01

    The Tibetan Plateau or Third Pole covers over 5 million km2, and has ~46,000 glaciers that collectively contain one of the Earth's largest stores of fresh water. The Guliya ice cap located in the western Kunlun Shan on the Qinghai-Tibetan Plateau, China, is the largest (> 200 km2) ice cap in the subtropical zone. In 1992, a 308.6 m ice core to bedrock was recovered from the Guliya ice cap. The deepest 20 meters yielded the first record extending back through the last glacial cycle found outside of the Polar Regions. Because of its continental location on the northwestern side of the Tibetan Plateau, the atmospheric circulation over the Guliya ice cap is dominated by westerly air flow from the Eurasian region. Therefore the site is expected to be unaffected by the fallout of anthropogenic trace metals originating from the inner Asian continent and rather may serve to characterize trace metal emissions from the western countries. Here we present preliminary results of the determination of 29 trace elements, Rb, Sr, Nb, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Ta, Tl, Pb, Bi, U, Li, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and As, from Guliya ice core samples spanning the period 1500 - 1992 AD at seasonal (1750-1992 AD) and annual (1500-1750 AD) resolution. This Guliya trace element record will complement the developing records from the Dasuopu glacier, central Himalaya, and from the Puruogangri ice cap in the western Tanggula Shan in central Tibetan Plateau, which in contrast to Guliya are influenced by the monsoon. We investigate the possible sources both natural and anthropogenic of atmospheric trace elements and their fluxes over the Tibetan Plateau during the last 500 years.

  17. Ground deformation associated with the 2008 Sichuan Earthquake in China, estimated using a SAR offset-tracking method

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Takada, Y.; Furuya, M.; Murakami, M.

    2008-12-01

    Introduction: A catastrophic earthquake struck China"fs Sichuan area on May 12, 2008, with the moment magnitude of 7.9 (USGS). The hypocenter and their aftershocks are distributed along the western edge of the Sichuan Basin, suggesting that this seismic event occurred at the Longmeng Shan fault zone which is constituted of major three active faults (Wenchuan-Maowen, Beichuan, and Pengguan faults). However, it is unclear whether these faults were directly involved in the mainshock rupture. An interferometry SAR (InSAR) analysis generally has a merit that we can detect ground deformation in a vast region with high precision, however, for the Sichuan event, the surface deformation near the fault zone has not been satisfactorily detected from the InSAR analyses due to a low coherency. An offset-tracking method is less precise but more robust for detecting large ground deformation than the interferometric approach. Our purpose is to detect the detail ground deformation immediately near the faults involved in the Sichuan event with applying the offset-tracking method. Analysis Method: We analyzed ALOS/PALSAR images, which have been taken from Path 471 to 476 of ascending track, acquired before and after the mainshock. We processed SAR data from the level-1.0 product, using a software package from Gamma Remote Sensing. For offset-tracking analysis we adopt intensity tracking method which is performed by cross-correlating samples of backscatter intensity of a master SAR image with samples from the corresponding search area of a slave image in order to estimate range and azimuth offset fields. We reduce stereoscopic effects that produce apparent offsets, using SRTM3 DEM data. Results: We have successfully obtained the surface deformation in range (radar look direction) component, while in azimuth (flight direction) no significant deformation can be detected in some orbits due to "gazimuth streaks"h that are errors caused by ionospheric effects. Some concluding remarks are

  18. Response of lake chemistry to atmospheric deposition and climate in selected Class I wilderness areas in the western United States, 1993-2009

    USGS Publications Warehouse

    Mast, M. Alisa

    2011-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, conducted a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. Understanding how and why lake chemistry is changing in mountain areas is essential for effectively managing and protecting high-elevation aquatic ecosystems. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) were evaluated over a similar period of record. A main objective of the study was to determine if changes in atmospheric deposition of contaminants in the Rocky Mountain region have resulted in measurable changes in the chemistry of high-elevation lakes. A second objective was to investigate linkages between lake chemistry and air temperature and precipitation to improve understanding of the sensitivity of mountain lakes to climate variability.

  19. Provenance of Pliocene and recent sedimentary deposits in western Amazônia, Brazil: Consequences for the paleodrainage of the Solimões-Amazonas River

    NASA Astrophysics Data System (ADS)

    Horbe, Adriana Maria Coimbra; Motta, Marcelo Batista; de Almeida, Carolina Michelin; Dantas, Elton Luiz; Vieira, Lucieth Cruz

    2013-10-01

    Integrated data on paleocurrents, the morphology of detrital minerals and zircon grains, chemical compositions and U-Pb geochronology, reveal that the flow of the modern Solimões-Amazonas River has changed from west to east since the Plio-Pleistocene. This finding is supported by several lines of evidence, including paleocurrent directions and detrital mineral assemblages in the Içá Formation and in recent sediments. The Içá Formation, which was most likely deposited during the Pliocene, has NE and SE paleocurrents, a high proportion of stable detrital mineral assemblages and U-Pb zircon ages that we interpreted as being derived from the Amazonian craton (e.g., the Rondonian-San Ignácio and Sunsas-Grenvillian geochronologic provinces) and neighboring provinces, including the Neoproterozoic to Cambrian Brazilian Pampean mobile belts. A small proportion is derived from the Cambrian to Silurian Famatinian continental arch. Another source is the Precambrian and Paleozoic basement from the Andes cordillera, which includes several metamorphic inliers in Colombia, Peru and Bolivia. The overlying recent deposits have different provenances and are characterized by a more variable detrital assemblage with zircon grains that are enriched in trace elements and depleted in Si and have Mesoproterozoic ages. In our interpretation, the erosion of the Iquitos Arch after deposition of the Içá Formation allowed the westward expansion of the Solimões-Amazonas system in the Plio-Pleistocene.

  20. Foraminiferal biostratigraphy, depositional environments and hydrocarbon source rock potential of sediments from five wells in the western offshore region of the Niger delta, Nigeria

    SciTech Connect

    Adekoya, A.A.

    1987-01-01

    The Tertiary lithostratigraphy of the Niger delta consists of three units: The Akata, Agbada and Benin Formations. The Akata formation is characterized by a uniform development of grey, silty, undercompacted marine shales, containing lenses of abnormally high pressured fine grained sandstones. These pro-delta shales were deposited predominantly under anoxic conditions, on the continental slope. The Akata Formation is of Paleocene to Early Miocene age. The Agbada Formation is of Miocene-Pliocene age, and consists of a paralic sequence of alternating sandstones and shales. These were deposited on the delta front, distributary channels and lower delta plain environments. The Benin Formation consists predominantly of massive, porous, freshwater-bearing sands, with local thin shale interbeds. This formation was deposited in alluvial environments, including the braided stream and meander belt systems of the upper delta plain. Foraminiferal biostratigraphic analyses were made of sediments from the Akata and Agbada Formations in the Okan-74, Mesan-B, Meji-29, ET-1, and EA-5 wells. Index planktonic foraminifera enabled the zonation of the individual stratigraphic sequences. Five benthonic foraminiferal zones and ten biofacies/biofacies complexes are defined and correlated across the study area. Rock evaluation pyrolysis results indicate that the sediments contain adequate organic matter for hydrocarbon generation, while the Tmax data confirm burial to depths corresponding to the oil generation window. The vitrinite reflectance data confirm that some of the sediments are mature, and hydrocarbons (predominantly gas) generation has taken place from the predominant type III kerogens present in the organic matter.

  1. Lead-isotopic compositions of diverse igneous rocks and ore deposits from southwestern New Mexico and their implications for early Proterozoic crustal evolution in the western United States.

    USGS Publications Warehouse

    Stacey, J.S.; Hedlund, D.C.

    1983-01-01

    Basement rocks in this area are 1750 m.y. old and extend northward through Colorado to Utah. Galena data show that the fraction of older sialic lead in these rocks increases toward the the Archaean craton in Wyoming. The crust apparently developed southward from Wyoming in stages at 2400 m.y. ago or before, 2100 m.y. ago and 1750 m.y. ago. The Laramide alkali to calc-alkaline rocks and their associated porphyry Cu and massive replacement deposits have similar 206Pb/204Pb ratios and are the least radiogenic in the region; their 206Pb/204Pb ratios are all 18.0. Pb isotopes in this region offer some criteria for prospecting purposes. The 206Pb/204Pb values for the larger ore deposits related to Laramide activity are all <18.0, particularly for the larger ones. Within the mid- Tertiary group, the same criteria apply - i.e. the largest deposits have the lowest 206Pb/204Pb ratios. -L.C.H.

  2. Genesis of the Bangbule Pb-Zn-Cu polymetallic deposit in Tibet, western China: Evidence from zircon U-Pb geochronology and S-Pb isotopes

    NASA Astrophysics Data System (ADS)

    Kan, Tian; Zheng, Youye; Gao, Shunbao

    2016-04-01

    The Banbule Pb-Zn-Cu skarn deposit is located in the Longger-Gongbujiangda volcanic magma arc in the Gangdese-Nyainqentanglha Plate. It is the only lead-zinc polymetallic deposit discovered in the westernmost Nyainqentanglha metallogenic belt. The measured and indicated resources include 0.9 Mt of Pb+Zn (4.77% Pb and 4.74% Zn, respectively), 6499 t of Cu, and 178 t of Ag (18.75g/t Ag). The orebodies mainly occur as lenses, veins and irregular shapes in the contact zone between the quartz-porphyry and limestone of the Upper Permian Xiala Formation, or in the boundaries between limestone and sandstone. Pb-Zn-Cu mineralization in the Banbule deposit is closely associated with skarns. The ore minerals are dominated by galena, sphalerite, chalcopyrite, bornite, and magnetite, with subordinate pyrite, malachite, and azurite. The gangue minerals are mainly garnet, actinolite, diopside, quartz, and calcite. The ore-related quartz-porphyry displays LA-ICP-MS zircon U-Pb age of 77.31±0.74 Ma. The δ34S values of sulfides define a narrow range of -0.8 to 4.7‰ indicating a magmatic source for the ore-forming materials. Lead isotopic systematics yield 206Pb/204Pb of 18.698 to 18.752, 207Pb/204Pb of 15.696 to 15.760, and 208Pb/204Pb of 39.097 to 39.320. The data points are constrained around the growth curves of upper crust and orogenic belt according to the tectonic discrimination diagrams. The calculated Δβ ‑ Δγ values plot within the magmatic field according to the discrimination diagram of Zhu et al. (1995). The S-Pb isotopic data suggest that Bangbule is a typical skarn deposit, and the Pb-Zn-Cu mineralization is genetically related to the quartz-porphyry in the mining district. The discovery of the Bangbule deposit indicates that there is metallogenic potential in the westernmost Nyainqentanglha belt, which is of great importance for the exploration work in this area.

  3. Nature, diversity of deposit types and metallogenic relations of South China

    USGS Publications Warehouse

    Zaw, K.; Peters, S.G.; Cromie, P.; Burrett, C.; Hou, Z.

    2007-01-01

    The South China Region is rich in mineral resources and has a wide diversity of deposit types. The region has undergone multiple tectonic and magmatic events and related metallogenic processes throughout the earth history. These tectonic and metallogenic processes were responsible for the formation of the diverse styles of base and precious metal deposits in South China making it one of the resource-rich regions in the world. During the Proterozoic, the South China Craton was characterised by rifting of continental margin before eruption of submarine volcanics and development of platform carbonate rocks, and the formation of VHMS, stratabound copper and MVT deposits. The Phanerozoic metallogeny of South China was related to opening and closing of the Tethyan Ocean involving multiple orogenies by subduction, back-arc rifting, arc-continent collision and post-collisional extension during the Indosinian (Triassic), Yanshanian (Jurassic to Cretaceous) and Himalayan (Tertiary) Orogenies. The Late Palaeozoic was a productive metallogenic period for South China resulting from break-up and rifting of Gondwana. Significant stratabound base and precious metal deposits were formed during the Devonian and Carboniferous (e.g., Fankou and Dabaoshan deposits). These Late Palaeozoic SEDEX-style deposits have been often overprinted by skarn systems associated with Yanshanian magmatism (e.g., Chengmenshan, Dongguashan and Qixiashan). A number of Late Palaeozoic to Early Mesozoic VHMS deposits also developed in the Sanjiang fold belt in the western part of South China (e.g., Laochang and Gacun). South China has significant sedimentary rock-hosted Carlin-like deposits, which occur in the Devonian- to Triassic-aged accretionary wedge or rift basins at the margin of the South China Craton. They are present in a region at the junction of Yunnan, Guizhou, and Guangxi Provinces called the 'Southern Golden Triangle', and are also present in NW Sichuan, Gansu and Shaanxi, in an area known as

  4. Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland - article no. GB2016

    SciTech Connect

    Cloy, J.M.; Farmer, J.G.; Graham, M.C.; MacKenzie, A.B.; Cook, G.T.

    2008-05-15

    Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (C-14, Pb-210) and analyzed (ICP-OES, ICP-MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e. g., Pb-206/Pb-207), clear indications of Pb contamination during the pre-Roman/Roman, post-Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were the most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian-Pb-influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the post industrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (similar to 10 to 40 mg m{sup -2} a{sup -1}) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m{sup 2} a{sup -1} by the early 2000s.

  5. Geologic map of the western Haji-Gak iron deposit, Bamyan Province, Afghanistan, modified from the 1965 original map compilation of V.V. Reshetniak and I.K. Kusov

    USGS Publications Warehouse

    Renaud, Karine M.; Tucker, Robert D.; Peters, Stephen G.; Stettner, Will R.; Masonic, Linda M.; Moran, Thomas W.

    2011-01-01

    This map is a modified version of Geologic-prospecting plan of western area of Hajigak iron-ore deposit, scale 1:2,000, which was compiled by V.V. Reshetniak and I.K. Kusov in 1965. (Refer to the References Cited section in the Map PDF for complete citations of the original map and related reports.) USGS scientists, in cooperation with the Afghan Geological Survey and the Task Force for Business and Stability Operations of the U.S. Department of Defense, studied the original documents and also visited the field area in November 2009. This modified map illustrates the geological structure of the western Haji-Gak iron deposit and includes cross sections of the same area. The map reproduces the topology (contacts, faults, and so forth) of the original Soviet map and includes modifications based on our examination of that document. We constructed the cross sections from data derived from the original map. Elevations on the cross sections are derived from the original Soviet topography and may not match the newer topography used on the current map. We have attempted to translate the original Russian terminology and rock classification into modern English geologic usage as literally as possible without changing any genetic or process-oriented implications in the original descriptions. We also use the age designations from the original map. The unit colors on the map and cross sections differ from the colors shown on the original version. The units are colored according to the color and pattern scheme of the Commission for the Geological Map of the World (CGMW) (http://www.ccgm.org).

  6. Regional geology of the low-permeability, gas-bearing Cleveland Formation, western Anadarko Basin, Texas Panhandle: Lithologic and depositional facies, structure, and sequence stratigraphy

    NASA Astrophysics Data System (ADS)

    Hentz, Tucker F.

    1992-09-01

    The Upper Pennsylvania (lower Missourian) Cleveland formation produces gas from low-permeability ('tight') sandstone reservoirs in the western Anadarko Basin of the northeastern Texas Panhandle. In the six-county region, these reservoirs had produced more than 412 Bcf of natural gas through December 31, 1989. Because of their typically low permeability, the Cleveland sandstones require acidizing and hydraulic fracture treatment to produce gas at economic rates. Since 1982, the Gas Research Institute has supported geological investigations throughout the United States to develop the scientific and technological knowledge for producing from low-permeability, gas-bearing sandstones. As part of the program and the GRI Tight Gas Sands project, the Bureau of Economic Geology has been conducting research on low-permeability sandstones in the Cleveland formation and on several other sandstone units of similar character in Texas and Wyoming.

  7. Distribution and Mobilization of Arsenic in the Ganges plain sedimentary deposits of South-western Bangladesh; implications from field and laboratory observations

    NASA Astrophysics Data System (ADS)

    Rahman, M.; Mano, A.; Udo, K.; Ishibashi, Y.; Han, Y.

    2011-12-01

    The variation of arsenic concentration depending on sediment size and its depositional age in a variety of sediments extracted from four As contaminated sites of the southwestern Bangladesh were studied to elucidate the aquifer geological parameters that controls the vertical As distribution and mobilization in the sediment-water interface. It was found that sediment size, reactive surface area, relative depositional age and presence of other carrier minerals having higher affinity to adsorb As, may greatly dominate the arsenic accumulation. Sorption of As onto sediment surfaces was found to vary based on the variation of the particle diameters (2 to 250 μm), which eventually reflects the role of geological materials in controlling the As distribution in various depositional layers. Medium sands commonly found in the deeper aquifer (~150m), being older in age (> 7000 yrs BP) and having relatively larger diameter (φ~250 μm) were found to contain relatively low amount of As (0.8 μg/g) whereas higher As (5 to 25 μg/g) was identified noticeably in the recently deposited and reasonably younger (100 to 1000 yrs BP) sediment particles including clay and finer sands that commonly have moderately smaller diameter (φ~2 to 90 μm). These observations were supported strongly by the findings obtained from the laboratory batch adsorption tests conducted with those sediments. Presence of As was also observed to be greatly dependent on the availability of its carrier minerals particularly Fe and Al oxide/hydroxide along the aquifer depths. Clay particles with relatively moderate Fe and Al oxide minerals was found to adsorb as much as 70 μg/g As whereas medium sand with less Fe and Al oxide minerals were noticed to capture only 4 μg/g of As in the batch adsorption test. In laboratory leaching test, significant amount of As (12 μg/g) coupled with Fe (4.8 mg/g) were found to be leached out from the shallower brown clay by using sodium bicarbonate (pH~9) as the leaching agent

  8. The hydrologic and biogeochemical response of undisturbed mountain ecosystems in the Western United States to multiple stressors: Interactions between climate variability and atmospheric deposition of contaminants

    NASA Astrophysics Data System (ADS)

    Campbell, D. H.; Mast, M. A.; Clow, D. W.; Ingersoll, G. P.; Nanus, L.

    2004-12-01

    Wilderness areas and national parks of the West are largely protected from acute changes in land use such as urbanization and natural resource development. However, the ecosystems in these areas are sensitive to both climate variability and atmospheric deposition of acids, nitrogen (N), and toxic contaminants, and these stressors interact in ways that we are just beginning to understand. Here we examine some examples of the interactions between climate variability and nitrogen and mercury cycling in high elevation watersheds. During the recent drought, which began in 2000, streamwater nitrate concentrations nearly doubled in the Loch Vale watershed in Rocky Mountain National Park, exceeding 60 μ M during early snowmelt. Much of the elevated nitrate resulted from an increased percentage contribution to streamwater of nitrate-rich shallow groundwater. In a nearby pond used for breeding by a threatened amphibian species, nitrate concentrations were negligible but ammonium concentrations were extremely high (850 μ M) during the drought. In this case, organic N in pond sediments was likely mineralized and released during cycles of drying and rewetting of pond sediments. Even after 2 years of near-average precipitation, water levels remained below normal and ammonium concentrations remained elevated, indicating that the hydrologic response of this small system has a timescale of many years. Mercury (Hg) deposition at high elevations of the Rocky Mountains is comparable to that of the Midwest and Northeast, but the processes that control Hg cycling in alpine/subalpine ecosystems are not well understood. Methylation and bioaccumulation of Hg must occur before Hg reaches levels harmful to the ecosystem or human health, and both climate and nutrient cycling affect these processes. Fluctuating water levels caused by climate variability can mobilize Hg from lake and pond sediments, increasing reactivity and bioavailability of Hg in the ecosystem. Increased nutrient release

  9. OSL chronology of onshore cyclone deposits at Point Lefroy (Exmouth Gulf, Western Australia) - Implications for washover fan formation and regional cyclone activity

    NASA Astrophysics Data System (ADS)

    Brill, Dominik; May, Simon Matthias; Shah-Hosseini, Majid; Leopold, Matthias; Callow, Nik; Engel, Max; Scheffers, Anja; Brückner, Helmut

    2016-04-01

    Although frequently occurring, little is known about the geological imprint of (pre)historical tropical cyclones (TCs) in Northwestern Australia. Large washover fans at Point Lefroy (Exmouth Gulf) provide unambiguous morphological evidence of flooding by TCs capable to overtop and breach the local coastal barrier. Based on ground penetrating radar, unmanned aerial vehicle survey techniques, as well as geomorphological, sedimentological and chronological investigations, this research aims at reconstructing the formation of the washover fans, and understanding their significance for recording past TC activity. The stratigraphy of the washover fans is characterized by multiple depositional units, which are separated by palaeosurfaces with initial pedogenesis. Combining the chronostratigraphical record of the different washover fans at Point Lefroy is assumed to reflect the regional TC magnitude-frequency pattern, reaching far beyond historical records. While reworking of calcareous faunal remains biases the application of radiocarbon dating, we carried out optically stimulated luminescence (OSL) dating in order to establish a robust chronology of TC-induced washover deposition. OSL dating was challenged by spatially heterogeneous dose rates within the poorly sorted mixture of quartz and coral fragments, by incomplete signal resetting, and by sediment mixing during and, most likely, after transportation. However, by successfully constraining the contribution of each of these factors - using a combination of single-grain quartz dating, quasi-continuous luminescence profiling, spatially resolved dose rate determination, and dose rate modelling - the final chronology gives insight into the evolution of the geo-archive and, ultimately, into the local to regional TC history. Based on up to three sediment profiles from each fan structure, two different washover fans were OSL dated. While contemporaneous deposition at both landforms suggest that the two geomorphological

  10. Genesis of ilmenite-series I-type granitoids at the Baogutu reduced porphyry Cu deposit, western Junggar, NW-China

    NASA Astrophysics Data System (ADS)

    Cao, MingJian; Qin, KeZhang; Li, GuangMing; Evans, Noreen J.; Hollings, Pete; Jin, LuYing

    2016-03-01

    The Baogutu porphyry Cu deposit is a typical reduced porphyry Cu deposit, likely related to ilmenite-series I-type granitoids. However, the nature of the granitoids (ilmenite-series or magnetite-series) and the genesis of the Baogutu deposit are still under debate. In order to resolve these issues, whole-rock magnetic susceptibility, geochemistry and Sr-Nd-Pb isotopic, zircon U-Pb dating and Hf-O isotopic compositions were carried out. Three different intrusive phases are recognized within the deposit, from oldest to youngest, they are diorite with trace gabbro, diorite-granodiorite porphyry, and hornblende diorite porphyry, all of which were emplaced in the Late Carboniferous (320-306 Ma) and show a metaluminous, calc-alkaline I-type granitoid character with typical supra-subduction zone geochemical affinities. The intrusions are characterized by widespread primary pyrrhotite without anhydrite and hematite, dominant ilmenite over magnetite, low whole rock magnetic susceptibility (< 1 × 10- 4 emu g- 1 oe- 1 or < 3 × 10- 3 SI unit) and low whole rock Fe2O3/FeO ratios (< 0.4), indicating that the granitoids are ilmenite- rather than magnetite-series I-type granitoids. Whole rock Sr-Nd-Pb isotopic compositions show limited variation but slightly enriched characteristics with (87Sr/86Sr)i values of 0.70357-0.70404, εNd (t) of + 6.3 to + 7.8, 206Pb/204Pb of 18.20-19.54 and 208Pb/204Pb of 37.97-39.55. Zircon Hf-O isotopic compositions show εHf (t) values of + 10.7 to + 15.8 and δ18O of 5.3-7.4‰. Zircon and apatite saturation thermometries yield temperatures of 720 to 920 °C with relatively higher temperatures for the porphyries than for the diorite. Limited variations in Sr-Nd-Pb-Hf-O isotopic compositions and extremely young whole rock T2DM (Nd) (430 to 570 Ma) and zircon TDMC (Hf) (310 to 640 Ma) do not indicate significant crustal contamination during magma ascent or emplacement. Rather the Baogutu ilmenite-series I-type granitoids were probably formed by

  11. SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho: Implications for rifting of western Laurentia and synchroneity of Sturtian glacial deposits

    USGS Publications Warehouse

    Lund, K.; Aleinikoff, J.N.; Evans, K.V.; Fanning, C.M.

    2003-01-01

    In central Idaho roof pendants, a northwest-trending belt of metamorphosed strata, correlative with the Windermere Supergroup, links northern and southern segments of the western Laurentia Neoproterozoic rift belt. Nine newly named formations within the Gospel Peaks sequence-A through Gospel Peaks sequence-D record Cryogenian preglacial, rift-glacial, and postglacial events as well as Neoproterozoic III glacial and rift events. The Edwardsburg Formation of Gospel Peaks sequence B includes interfingered bimodal rift-related volcanic and glaciogenic diamictite strata. Zircons from a rhyodacite flow in the lower Edwardsburg Formation and from a rhyolite flow at its top, dated by using the sensitive high-resolution ion microprobe (SHRIMP), yielded a weighted average of 685 ?? 7 Ma and 684 ?? 4 Ma. Reevaluation of geochronology and correlations indicates that Cryogenian rifting may have been (1) protracted between 780 and 685 Ma, (2) diachronous along the Cordillera, and/or (3) stepwise with a Cordilleran-wide event at ca. 685 Ma that initiated the formation of the Cordilleran miogeocline and set its geometry. Reevaluation of the Cryogenian glacial record indicates that (1) two associated ca. 685 Ma glacial intervals in the Edwardsburg Formation correlate with the Rapitan glaciation, (2) the Sturtian snowball Earth event must be reevaluated on the basis of revision of Rapitan glaciation from 750-700 Ma to ca. 685 Ma, and (3) there were older Cryogenian glaciations or Cryogenian glaciations were not globally synchronous. New dates and correlations significantly impact the number and synchroneity of possible snowball Earth events and the paleolatitudes of Cryogenian glaciations. Western Laurentian events at ca. 685 Ma particularily affect Neoproterozoic paleocontinental reconstructions by indicating diachronous and multi step breakup of supercontinent Rodinia.

  12. A new geoarchaeology of Aboriginal artefact deposits in western NSW, Australia: establishing spatial and temporal geomorphic controls on the surface archaeological record

    NASA Astrophysics Data System (ADS)

    Fanning, Patricia C.; Holdaway, Simon J.; Rhodes, Ed J.

    2008-10-01

    Surface deposits of stone artefacts are the most common feature of the Australian Aboriginal archaeological record, but they remain difficult for archaeologists to interpret. Among the many reasons is a lack of understanding of geomorphic processes that have exposed the artefacts at the surface. We describe research on the geomorphic environments in arid Australia from which we have developed a new geoarchaeological framework for describing and analysing surface artefact deposits. Optically Stimulated Luminescence dating of sediments upon which the artefacts currently rest demonstrates that the landscape, and the archaeological record it preserves, is spatially and temporally discontinuous. Exposure and/or burial of artefacts is controlled by geomorphic processes operating on timescales ranging from a few decades to thousands of years and spatial scales of tens to many thousands of square meters. These same processes, operating on similar scales, also determine whether or not artefact scatters are preserved in the contemporary landscape or in the sedimentary record of past landscapes, and hence whether or not they become part of the archaeological record. Models of settlement behavior in hunter-gatherer peoples that are largely derived from analysis of surface 'sites' must take account of these discontinuities.

  13. Apparent constant exhumation of the Western European Alps during the last 5 Ma: constraints from detrital apatite thermochronology from foreland deposits

    NASA Astrophysics Data System (ADS)

    Glotzbach, C.; Bernet, M.; van der Beek, P.

    2009-12-01

    Sediment budgets and a compilation of in-situ thermochronological data independently suggest an increase at ~5 Ma of both the sediment flux out of, and the exhumation rates in the European Alps (Cederbom et al. 2004; Kuhlemann 2000; Vernon et al. 2008). A simultaneous climate change was used to argue for a climatic control on the ‘5 Ma event’ (Cederbom et al. 2004; Willett et al., 2006). More local low-temperature thermochronological studies, however, have failed to clearly record this exhumation event, but suggest an increase in exhumation at different times, for instance before 6.5 Ma and after 3 Ma in the Mont Blanc massif (Glotzbach et al. 2008). In this study we applied detrital apatite fission-track thermochronology to Pliocene-Miocene Molasse and modern river sediments in the Chambaran foreland basin remnant of the French Western Alps. The main aim of this study is to better resolve the controversially discussed exhumation and erosion history of the Alps and their tectonic and climatic driving forces. In total 14 Molasse sediments and 3 modern river samples were dated. Resulting age probability plots suggest that today and during the Messinian Salinity Crisis (Uppermost Miocene) a large fraction of sediments originate from recycling of older Miocene sediments. Additionally, marine Miocene sediments are characterized by the presence of pre-Alpine AFT ages (up to 1.2 Ga), with peak ages dating to the Jurassic and Late Cretaceous. These ‘old’ ages are most likely delivered from the nearby Massif Central basement, supported by similar in-situ AFT ages in that area and sedimentological studies, which suggest that in general sediments are originated from erosion of the Western Alps but with a minor contribution from the Massif Central. Comparing the stratigraphic age of the samples with the youngest predicted age peak suggests a constant lag-time of ~6 Myr throughout the Pliocene, in contrast to lag-times <5 Myr for the Miocene samples. This implies that

  14. Trace elements in corundum, chrysoberyl, and zircon: Application to mineral exploration and provenance study of the western Mamfe gem clastic deposits (SW Cameroon, Central Africa)

    NASA Astrophysics Data System (ADS)

    Kanouo, Nguo Sylvestre; Ekomane, Emile; Yongue, Rose Fouateu; Njonfang, Emmanuel; Zaw, Khin; Changqian, Ma; Ghogomu, Tanwi Richard; Lentz, David R.; Venkatesh, Akella Satya

    2016-01-01

    Trace element abundances in three indicator minerals (corundum, chrysoberyl, and zircon grains) from the western Mamfe gem placers, as determined by LA-ICP-MS analytical techniques, are shown to be sensitive to their crystallization conditions and source rock types. Corundum is dominantly composed of Al (standardized at 529,300 ppm), Fe (2496-12,899 ppm), and Ti (46-7070 ppm). Among element ratios, Fe/Mg (73-1107), Fe/Ti (0.5-245.0), Ti/Mg (1-175), and Ga/Mg (4-90) are generally higher whereas, Cr/Ga (<0.072) is low. The Fe (≤12,899), Ga (≤398), Mg (2-62), Cr (1.1-33.0), and V (3.0-93.0) contents (in ppm) mostly typify corundum grains formed in magmatic rocks, although some are metamorphic affiliated. A very higher Ti and significantly low Ga, Ta and Nb contents in some blue grains, suggest interesting concentrations of those high-tech metals in their source rocks. Chrysoberyl is dominantly composed of Al (standardized at 425,000 ppm) and Be (62701-64371 ppm). Iron (7605-9225 ppm), Sn (502-3394 ppm), and Ti (33-2251 ppm) contents are high, whereas Ga (333-608 ppm), Ta (<456.0 ppm), and Nb (<3.0 ppm) are significantly low. The high (Be and Sn) and significantly low Ga-Rb abundances, and Ta > Nb in the western Mamfe chrysoberyls show that they were crystallized in granitic pegmatites, with some of those source rocks being enriched in Ta and Sn. Zirconium oxide (ZrO2: standardized at 66.1 wt.%)) is the only major oxide in analysed coarse-grained zircons. Within the minor elementary suites: Hf (4576-12,565 ppm) and Y (48-2805 ppm) contents are significantly high. The trace element suites include: Th (7-1565 ppm), U (13-687 ppm), and ∑REE (50-2161 ppm), whose values are significantly low. The (Yb/Sm)N, Ce/Ce*, and Eu/Eu* anomalies range from 1.0 to 227.0, 0 to 308, and 0.08 to 1.7 respectively. They are Hf-Y-HREE enriched and depleted zircons mainly crystallized in magmatic oxidized environments. They were mainly sorted from granitoids, syenites and kimberlites.

  15. Concentrations of selected metals in Quaternary-age fluvial deposits along the lower Cheyenne and middle Belle Fourche Rivers, western South Dakota, 2009-10

    USGS Publications Warehouse

    Stamm, John F.; Hoogestraat, Galen K.

    2012-01-01

    The headwaters of the Cheyenne and Belle Fourche Rivers drain the Black Hills of South Dakota and Wyoming, an area that has been affected by mining and ore-milling operations since the discovery of gold in 1875. A tributary to the Belle Fourche River is Whitewood Creek, which drains the area of the Homestake Mine, a gold mine that operated from 1876 to 2001. Tailings discharged into Whitewood Creek contained arsenopyrite, an arsenic-rich variety of pyrite associated with gold ore, and mercury used as an amalgam during the gold-extraction process. Approximately 18 percent of the tailings that were discharged remain in fluvial deposits on the flood plain along Whitewood Creek, and approximately 25 percent remain in fluvial deposits on the flood plain along the Belle Fourche River, downstream from Whitewood Creek. In 1983, a 29-kilometer (18-mile) reach of Whitewood Creek and the adjacent flood plain was included in the U.S. Environmental Protection Agency's National Priority List of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, commonly referred to as a "Superfund site." Listing of this reach of Whitewood Creek was primarily in response to arsenic toxicity of fluvial deposits on the flood plain. Lands along the lower Cheyenne River were transferred to adjoining States and Tribes in response to the Water Resources Development Act (WRDA) of 1999. An amendment in 2000 to WRDA required a study of sediment contamination of the Cheyenne River. In response to the WRDA amendment, the U.S. Geological Survey completed field sampling of reference sites (not affected by mine-tailing disposal) along the lower Belle Fourche and lower Cheyenne Rivers. Reference sites were located on stream terraces that were elevated well above historical stream stages to ensure no contamination from historical mining activity. Sampling of potentially contaminated sites was performed on transects of the active flood plain and adjacent terraces that could

  16. A mixture of mantle and crustal derived He-Ar-C-S ore-forming fluids at the Baogutu reduced porphyry Cu deposit, western Junggar

    NASA Astrophysics Data System (ADS)

    Cao, MingJian; Qin, KeZhang; Li, GuangMing; Evans, Noreen J.; He, HuaiYu; Jin, LuYing

    2015-02-01

    Most large to huge porphyry Cu deposits (PCDs) are oxidized, making the Baogutu reduced porphyry Cu deposit (RPCD) a relative rarity. CH4-bearing ore-forming fluids formed at several hydrothermal stages, however, their source is still unclear. To address this issue, isotopic investigations of sulfide He-Ar-S and calcite C were conducted. Fluid inclusions hosted in sulfides (arsenopyrite, chalcopyrite and pyrite) showed 3He/4He ratios of 0.06-0.30 Ra (Ra is the 3He/4He ratio of air = 1.39 × 10-6), 40Ar/36Ar of 311-405, 40Ar∗/4He of 0.06-1.01, and F4He ratios of 902-11,074 (sample BGT-Py 2 yielded a ratio of 100), indicating a predominantly crustal source for the fluids with minor mantle input (less than 5%). The δ13C values of carbonate yielded a value of -7.8‰ (n = 3), implying that CO2 was probably sourced from mantle or juvenile lower crust. According to the restricted sulfide δ34S values, the total S isotopic composition of the hydrothermal system was estimated to be 0.0-0.5‰, suggesting that the sulfur was derived from mantle or lower crust magmatic source. According to the published granitoids Nd isotopic compositions at the Baogutu RPCD, fairly young TDM model ages (450-650 Ma) suggest that the granitoids were derived from partial melting of a juvenile basaltic lower crust. Thus, we propose that small proportion of mantle-derived fluids (less than 5%), probably rise up and then mix with the fluids of juvenile lower crust under an extensional tectonic setting, forming the mantle-derived Sr-Nd-Pb-S-C but crustal He-Ar isotopic compositions.

  17. Relationships of silica, barite, organic material, and sulfide minerals at the Red Dog Zn-Pb-Ag deposit, western Brooks Range, Alaska

    SciTech Connect

    Sims, D.B. . Dept. of Geosciences)

    1992-01-01

    Relationships of silica, barite, organic material, and sulfide minerals at Cominco Alaska's Red Dog mine indicate that organic material was driven from carbonaceous shale during one or more silicification and mineralization events, and deposited with barite on the seafloor. Red Dog is a strata-bound accumulation of barite, silica, and sulfide minerals. Massive sulfide mineralization consisting of sphalerite, pyrite, marcasite, and galena is concentrated within the upper portion of the Mississippian-Pennsylvanian Ikalukrok shale, and the lower portion of the conformably overlying Ikalukrok barite. Mineralization below the massive sulfide horizon comprises veins and disseminated grains of sulfide minerals in silicified shale. The concentration of sulfide minerals and silica decreases, and the total organic carbon content of shale increases with depth. Mineralization above the massive sulfide horizon comprises silicified barite with disseminated and vein-controlled sulfide minerals. The total organic carbon content of ore is generally low. Silicified Ikalukrok shale has been depleted of organic carbon with respect to unaltered shale. Within the mineralized shale and massive sulfide horizons, trace amounts of organic material occur with barite in small vugs and veins that cross-cut mineralized and silicified rock. Similar organic material also occurs in the barite section. Where the barite is silicified, the organic material pre-dates silica. Sulfide minerals pre-date, and are cogenetic with silica in altered and mineralized barite. These relationships indicate that organic material was displaced from shale and transported with a fluid that deposited it with barite on the seafloor. The zone of silica and sulfide replacement migrated or expanded upward from the shale into the barite as the thickness of the barite section increased.

  18. Descriptive and geoenvironmental model for Co-Cu-Au deposits in metasedimentary rocks: Chapter G in Mineral deposit models for resource assessment

    USGS Publications Warehouse

    Slack, John F.; Johnson, Craig A.; Causey, J. Douglas; Lund, Karen; Schulz, Klaus J.; Gray, John E.; Eppinger, Robert G.

    2013-01-01

    Additional geologically and compositionally similar deposits are known, but have average Co grades less than 0.1 percent. Most of these deposits contain cobalt-rich pyrite and lack appreciable amounts of distinct Co sulfide and (or) sulfarsenide minerals. Such deposits are not discussed in detail in the following sections, but these deposits may be revelant to the descriptive and genetic models presented below. Examples include the Scadding Au-Co-Cu deposit in Ontario, Canada; the Vähäjoki Co-Cu-Au deposit in Finland; the Tuolugou Co-Au deposit in Qinghai Province, China; the Lala Co-Cu-UREE deposit in Sichuan Province, China; the Guelb Moghrein Cu-Au-Co deposit in Mauritania; and the Great Australia Co-Cu, Greenmount Cu-Au-Co, and Monakoff Cu-Au-Co-UAg deposits in Queensland, Australia. Detailed information on these deposits is presented in appendix 2.

  19. A regional record of expanded Holocene wetlands and prehistoric human occupation from paleowetland deposits of the western Yarlung Tsangpo valley, southern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Hudson, Adam M.; Olsen, John W.; Quade, Jay; Lei, Guoliang; Huth, Tyler E.; Zhang, Hucai

    2016-07-01

    The Asian Monsoon, which brings ∼80% of annual precipitation to much of the Tibetan Plateau, provides runoff to major rivers across the Asian continent. Paleoclimate records indicate summer insolation and North Atlantic paleotemperature changes forced variations in monsoon rainfall through the Holocene, resulting in hydrologic and ecologic changes in plateau watersheds. We present a record of Holocene hydrologic variability in the Yarlung Tsangpo (YT) valley of the southern Tibetan Plateau, based on sedimentology and 14C dating of organic-rich 'black mats' in paleowetlands deposits, that shows changes in wetlands extent in response to changing monsoon intensity. Four sedimentary units indicate decreasing monsoon intensity since 10.4 ka BP. Wet conditions occurred at ∼10.4 ka BP, ∼9.6 ka BP and ∼7.9-4.8 ka BP, with similar-to-modern conditions from ∼4.6-2.0 ka BP, and drier-than-modern conditions from ∼2.0 ka BP to present. Wetland changes correlate with monsoon intensity changes identified in nearby records, with weak monsoon intervals corresponding to desiccation and erosion of wetlands. Dating of in situ ceramic and microlithic artifacts within the wetlands indicates Epipaleolithic human occupation of the YT valley after 6.6 ka BP, supporting evidence for widespread colonization of the Tibetan Plateau in the early and mid-Holocene during warm, wet post-glacial conditions.

  20. Metamorphic Study along the Wenchuan Thrust (Longmen Shan, Sichuan, China); a Key to Understand the Two Phases of Thickening of the Eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    de Sigoyer, J.

    2015-12-01

    The Longmen Shan mountain belt, represents the eastern margin of Tibetan plateau (Sichuan, China) and culminated over 7000m. Despite very low convergent rate observed across his belt, it is active as attested by the Wenchuan earthquake Mw 7.9 (2008) that rupture and out of sequence thrust in this belt. The formation of this mountain bet results from two orogenic phase, one at the end of Trias (due to the closure of the Paleotethys), and one during Cenozoic time following the Indian Asia collision. This study aims to identify the deformation and metamorphism related to Mesozoic event and those relate to Cenozoic evolution. Structural, microstructural, metamorphic observations, PT estimates (graphitization of carbonaceous material, quantified X-ray images, chlorite-phengite-quartz-water multi-equilibrium and thermodynamic modelling) and U-Pb geochronology are used to describe the tectono-metamorphic evolution of the Xuelongbao area in the internal part of the Longmen Shan belt (eastern border of the Tibetan plateau, Sichuan, China). The Xuelongbao granite is dated at 765±7 Ma (in situ U/Pb dating on zircon), indicating that it forms part of the western Neoproterozoic South China block basement. The deformation in the western sedimentary cover above the Xuelongbao massif is intense, with step cleavage, twisted fold axes and CS structures with top to the SE thrusting vergence. Four stages of deformation are described, three of them are related to the Mesozoic wedge thickening, and the last one is due to the Cenozoic deformation. An inverted metamorphic gradient from 470°C, 8 kbar to 620°C, 13 kbar is identified in the cover above the Xuelongbao basement, suggesting a stack of sedimentary slices during the propagation of the Mesozoic accretionary wedge on the South China block margin. This decollement zone has been exhumed during the Cenozoic D4 exhumation of the Xuelongbao basement along the Wenchuan thrust, where greenschist overprint is observed.

  1. A Landslide Monitoring Network based on Multi-source Spatial Sensors in Li County, Sichuan Province, China

    NASA Astrophysics Data System (ADS)

    Lu, P.

    2014-12-01

    A multi-source spatial sensor network has been established to strengthen the landslide monitoring activities in the mountainous areas in Western China. The focused Xishancun landslide is in Li County in Sichuan Province, located in the upper Minjiang River areas that is thought as very unstable slope areas after the "5.12" Wenchuan Earthquake. This spatial sensor chiefly concentrates on constructing a monitoring network with four hierarchies of observation: (1) space-borne sensors including VHR optical images (P5, IKONOS, WorldView-1,2 and ZY-3) and a series of X-band TerraSAR-X SAR images; (2) aerial observation by a group of UAV scanning schemes with the ground-based controlling platform, the produced the 1:2000 scale DOM mosaic images and the generated high resolution DEM; (3) ground-based sensors involving in-situ sensors such as inclinometers and piezometers with a smart self-forming seamless real-time data communication and terrestrial remote sensing platform of laser scanning and ground-based SAR; and (4) internal investigation from geophysical approaches such as seismological and electromagnetic analyses. This landslide monitoring system based on spatial sensor network is expected to provide solid monitoring data for landslide models and data assimilation for potential landslide hazard prediction and risk assessment.

  2. Minerals and clay minerals assemblages in organic-rich facies: the case study of the Sinemurian-Pliensbachian carbonate deposits of the western Lusitanian Basin (Portugal)

    NASA Astrophysics Data System (ADS)

    Caniço, Ana; Duarte, Luís V.; Silva, Ricardo L.; Rocha, Fernando; Graciano Mendonça Filho, João

    2015-04-01

    The uppermost Sinemurian-Pliensbachian series of the western part of the Lusitanian Basin is composed by hemipelagic carbonates particularly enriched in organic matter. Great part of this succession, considered to be one of the most important potential source rock intervals of Portugal, crops out in the S. Pedro de Moel and Peniche sectors, belonging to the Água de Madeiros and Vale das Fontes formations. In this study, supported by a detailed and integrated stratigraphic framework, we analyzed 98 marly samples (whole-rock mineralogy and clay minerals assemblages) from the aforementioned formations in the S. Pedro de Moel and Peniche sectors. X-ray Diffraction analysis followed the standard procedures and the semi-quantification of the different mineral phases was calculated using MacDiff 4.2.6. The goals of this work are to demonstrate the vertical variability of the mineral composition of these two units and investigate the relationship between the clay minerals assemblages and the content in organic matter (Total organic carbon: TOC). Besides the abundance of calcite and phyllosilicates, whole-rock mineralogy revealed the presence of quartz, potassium feldspar, dolomite, and pyrite (trace amounts). Other minerals like anhydrite, barite and gypsum occur sporadically. The clay minerals assemblages are dominated by illite+illite/smectite mixed-layers (minimum of 59%), always associated with kaolinite (maximum of 37%) and chlorite (maximum of 25%); sporadically smectite occurs in trace amounts. Generally, high TOC levels (i.e., black shale facies with TOC reaching up to 22 wt.% in both units, see Duarte et al., 2010), show a major increase in chlorite and kaolinite (lower values of illite+illite/smectite mixed layers). A kaolinite enrichment is also observed just above the Sinemurian-Pliensbachian boundary (base of Praia da Pedra Lisa Member of Água de Madeiros Formation; values varying between 30 and 37%). This event is associated with a second-order regressive

  3. Psychological Distress among Adolescents in Chengdu, Sichuan at 1 Month after the 2008 Sichuan Earthquake

    PubMed Central

    Yu, Xiaonan; Zhang, Jianxin; Mak, Winnie W. S.; Choi, Kai Chow; Lui, Wacy W. S.; Zhang, Jianxin; Chan, Emily Y. Y.

    2010-01-01

    A devastating earthquake occurred on May 12, 2008 in Sichuan, China. This study investigated the prevalence and factors in association with psychological problems among secondary school students living in Chengdu (90 km away from the disaster epicenter) in June 2008. In a cross-sectional survey, 3,324 secondary students self-administered a structured questionnaire in classroom setting. Validated scales were used in this study. Among all respondents, 22.3% reported post-traumatic stress disorder (PTSD); 22.6% were probable depression cases; 10.6% reported suicidal ideation; and 14.1% would like to receive psychological counseling. No gender differences were found. While social/emotional support from teachers or peers (OR from 0.40 to 0.78) and exposure to positive news reports (OR from 0.59 to 0.62) were found protective, prior experience of severe mental distress (OR from 1.60 to 2.68) and corporal punishment (OR from 1.31 to 1.58), worry about future aftershocks (OR from 1.64 to 3.11), absence from school when it was not closed (OR from 1.38 to 1.48), exposures to scary or sorrowful disaster media coverage (OR from 1.39 to 2.07), post-disaster visits to affected sites (OR from 1.51 to 1.59), separation from parents (OR = 1.61), etc., were risk factors predictive of some of the aforementioned psychological problems. Negative mental health impacts were prevalent among the respondents. Teachers, parents, and the mass media are all important in maintaining good mental health among adolescents that are indirectly affected by the severe earthquake. The results have important implications for earthquake preparedness and relief work in the future. PMID:20405226

  4. Carbon-isotope stratigraphy of Early Cretaceous (Urgonian) shoal-water deposits: Diachronous changes in carbonate-platform production in the north-western Tethys

    NASA Astrophysics Data System (ADS)

    Huck, S.; Heimhofer, U.; Immenhauser, A.; Weissert, H.

    2013-05-01

    photozoan-dominated rudist-rich platform ecosystem, referred to as Urgonian limestones sensu stricto, occurred at the Early-Late Barremian transition. The onset of changes in the carbonate production mode ("heterozoan" versus "mixed heterozoan-photozoan" versus "photozoan") clearly predates the onset of similar lithological changes in the Helvetic realm by about 1.0 to 1.2 Myr. The established chronostratigraphic framework points to a link between the change towards photozoan-dominated limestones and fading palaeoenvironmental perturbations related to the mid-Barremian event, which is associated with major faunal turnovers and the onset of cyclic black-shale deposition in the central Tethyan realm. Judging from palaeoenvironmental proxies including kaolinite, phosphorus and black marl-limestone ratios, oscillating predominantly humid and relatively arid greenhouse conditions modulated the observed pattern in Urgonian carbonate platform production mode and the varying frequencies of black-shale deposits in the Tethyan and Boreal realms. Transient blooms of the orbitolinid foraminifera Palorbitolina lenticularis at the onset of a marked Upper Barremian positive carbon-isotope shift are interpreted to reflect increasing nutrient influx, most probably related to accelerated hydrological cycling and/or sea-level rise. These strata do not represent an over-regional correlatable lithostratigraphic unit, but likely an expression of progressive Northern Tethyan environmental and oceanographic change possibly related to Ontong Java large igneous province volcanism in the prelude of oceanic anoxic event 1a (OAE).

  5. The geology and mineral deposits of part of the western half of the Hailey 1 degree x 2 degrees quadrangle, Idaho; with sections on the Neal mining district and the Dixie mining district

    USGS Publications Warehouse

    Bennett, Earl H.

    2001-01-01

    Rocks in the western half of the Hailey 1 ?? 2 ? quadrangle of south-central Idaho include various units of the Atlanta lobe of the Idaho batholith (biotite granodiorite to two-mica granite) of Cretaceous age and plutons and dikes of Tertiary (Eocene to Miocene) age that intrude the batholith. Eocene plutonic rocks consist of a bimodal suite of anorogenic granite and tonalite-granodiorite and hypabyssal rhyolite and rhyodacite dikes. Rocks of the Eocene Challis Volcanics are scarce in the map area but are widespread to the east. Rhyolite ash flows of the Miocene Idavada Volcanics and basalt of the Snake River Plain crop out in the southern part of the area. Lacustrine rocks of probable Eocene to Holocene age are present in the vicinity of Anderson Ranch Reservoir. Quaternary basalts and gravels are widespread on the South Fork of the Boise River, and alluvial deposits are common along active drainages. Metasedimentary rocks of unknown age crop out on House Mountain, Chimney Peak, and on the ridges east of Anderson Ranch Reservoir. Older structures in the Idaho batholith include a major fault beneath House Mountain that may be a decollement for one of the large thrust sheets in eastern Idaho or part of an extensional core complex. The southern part of the Atlanta lobe of the Idaho batholith is cut by northeast-striking faults (parallel with the Trans-Challis fault system) that are related to Eocene extension and by northwest-oriented faults that formed during basin and range extension in the Miocene. The basin and range faults have prominent scarps typical of basin and range topography. The combination of northeast and northwest faults has broken the batholith into a series of rhomboid blocks. Some of these northeast and northwest faults are older structures that were reactivated in the Eocene or Miocene, as indicated by Ar 40 /Ar 39 dates on mineralized rock contained in some of the structures. The Idaho batholith and associated rocks in the map area host several

  6. Mineralogy, geochemistry and petrogenesis of the V-Ti-bearing and chromiferous magnetite deposits hosted by Neoarchaean Channagiri Mafic-Ultramafic Complex, Western Dharwar Craton, India: Implications for emplacement in differentiated pulses

    NASA Astrophysics Data System (ADS)

    Devaraju, Tadasore; Jayaraj, Kallada; Sudhakara, Thavaraghatta; Alapieti, Tuomo; Spiering, Beate; Kaukonen, Risto

    2014-12-01

    The Channagiri Mafic-Ultramafic Complex occupies lowermost section of the Neoarchaean Shimoga supracrustal group in the Western Dharwar Craton. It is a segmented body occupying the interdomal troughs of granitoids. The magnetite deposits occur in the northeastern portion; typically occupying the interface zone between gabbro and anorthositic. Mineralogically, the deposits are simple with abundant magnetite and ilmenite. Hogbomite is a consistent minor mineral. Magnetites are typically vanadiferous (0.7-1.25% V2O5). Ilmenite consistently analyses more MgO and MnO than coexisting magnetite. Chlorite, almost the only silicate present; lies in the range of ripidolite, corundophilite and sheridanite. The chromiferous suit occupying eastern side of Hanumalapur block (HPB) contains Fe-Cr-oxide analysing 37.8-11.9% Cr2O3 and 40.5-80% FeOt. In these too, chlorite, typically chromiferous (0.6-1.2% Cr2O3), is the most dominant silicate mineral. Geochemistry of V-Ti-magnetite is dominated by Fe, Ti and V with Al, Si, Mg and Mn contributing most of the remaining. Cr, Ni, Zn, Co, Cu, Ga and Sc dominate trace element geochemistry. The Cr-magnetite is high in Cr2O3 and PGE. Two separate cycles of mafic magmatism are distinguished in the CMUC. The first phase of first cycle, viz., melagabbro-gabbro, emplaced in the southeastern portion, is devoid of magnetite deposits. The second phase, an evolved ferrogabbroic magma emplaced in differentiated pulses, occupying northeastern portion of the complex, consists of melagabbro→gabbro-anorthosite→V-Ti magnetite→ferrogabbro sequence. Increase in oxygen fugacity facilitated deposition of V-Ti magnetite from ferrogabbroic magma pulse emplaced in late stages. The second cycle of chromiferous PGE mineralized suite comprises fine-grained ultramafite→alternation of pyroxinite-picrite→Crmagnetite sequence formed from fractionation of ferropicritic magma. HPB also includes >65m thick sill-like dioritic phase at the base of the ferriferous

  7. Mineralogy, geochemistry and petrogenesis of the V-Ti-bearing and chromiferous magnetite deposits hosted by Neoarchaean Channagiri Mafic-Ultramafic Complex, Western Dharwar Craton, India: Implications for emplacement in differentiated pulses

    NASA Astrophysics Data System (ADS)

    Devaraju, Tadasore C.; Jayaraj, Kallada R.; Sudhakara, Thavaraghatta L.; Alapieti, Tuomo T.; Spiering, Beate; Kaukonen, Risto J.

    2014-12-01

    The Channagiri Mafic-Ultramafic Complex occupies lowermost section of the Neoarchaean Shimoga supracrustal group in the Western Dharwar Craton. It is a segmented body occupying the interdomal troughs of granitoids. The magnetite deposits occur in the northeastern portion; typically occupying the interface zone between gabbro and anorthositic. Mineralogically, the deposits are simple with abundant magnetite and ilmenite. Hogbomite is a consistent minor mineral. Magnetites are typically vanadiferous (0.7-1.25% V2O5). Ilmenite consistently analyses more MgO and MnO than coexisting magnetite. Chlorite, almost the only silicate present; lies in the range of ripidolite, corundophilite and sheridanite. The chromiferous suit occupying eastern side of Hanumalapur block (HPB) contains Fe-Cr-oxide analysing 37.8-11.9% Cr2O3 and 40.5-80% FeO t . In these too, chlorite, typically chromiferous (0.6-1.2% Cr2O3), is the most dominant silicate mineral. Geochemistry of V-Ti-magnetite is dominated by Fe, Ti and V with Al, Si, Mg and Mn contributing most of the remaining. Cr, Ni, Zn, Co, Cu, Ga and Sc dominate trace element geochemistry. The Cr-magnetite is high in Cr2O3 and PGE. Two separate cycles of mafic magmatism are distinguished in the CMUC. The first phase of first cycle, viz., melagabbro-gabbro, emplaced in the southeastern portion, is devoid of magnetite deposits. The second phase, an evolved ferrogabbroic magma emplaced in differentiated pulses, occupying northeastern portion of the complex, consists of melagabbro→gabbro-anorthosite→V-Ti magnetite→ferrogabbro sequence. Increase in oxygen fugacity facilitated deposition of V-Ti magnetite from ferrogabbroic magma pulse emplaced in late stages. The second cycle of chromiferous PGE mineralized suite comprises fine-grained ultramafite→alternation of pyroxinite-picrite→Crmagnetite sequence formed from fractionation of ferropicritic magma. HPB also includes >65m thick sill-like dioritic phase at the base of the

  8. Euxinia prior to end-Permian main extinction at Xiaojiaba section, Sichuan Province, South China

    NASA Astrophysics Data System (ADS)

    Wei, H.; Algeo, T. J.; Chen, D.; Yu, H.

    2013-12-01

    Redox conditions in the global ocean prior to, during, and following the end-Permian mass extinction at 252.28 Ma remain contentious. Previous studies in western Australia, South China, and East Greenland have shown that photic-zone euxinia was present at least intermittently from the early Changhsingian through the Dienerian1-3. Here we report a study of organic carbon isotopes, pyrite sulfur isotopes, TOC, pyritic sulfur content, REE, and major and trace elements from the Upper Permian Xiaojiaba section in the Chaotian district of Guangyuan City, Sichuan Province, China. During the Permian-Triassic transition, this section was located on the northwestern margin of the South China Block, facing the Paleo-Tethys Ocean. Our results indicate that suboxic conditions prevailed during the Wuchiapingian and suboxic to anoxic conditions with several pulses of euxinia during the Changhsingian. δ13Corg values are mostly -28‰ to -26‰ but show three positive excursions (to -22‰) prior to the end-Permian mass extinction horizon. These positive excursions are associated with higher Spy concentrations (to ~1%). δ34Spy values are variable (from -41‰ to +5‰) but show a sharp negative excursion in the late Changhsingian (to -43.4‰) that coincided with the most positive δ13Corg values. This horizon is also associated with increases in Eu/Eu*, Baxs, ∑REE, Si, and redox-sensitive metals such as V. These patterns reflect linkage of the C and S cycles during the latest Permian, possibly in response to redox controls. The observed positive excursions in δ13Corg may be due to organic inputs from green sulfur bacteria, which exhibit a smaller photosynthetic fractionation (-12.5‰4) than eukaryotic algae. The pronounced negative excursion of δ34Spy corresponds to a sulfate-sulfide S isotope fractionation of about -60‰, suggesting a large flux of syngenetic framboidal pyrite, which would be indicative of euxinic water-column conditions. We infer that the euxinia prior

  9. Geochemistry of rare earth elements in the Baba Ali magnetite skarn deposit, western Iran - a key to determine conditions of mineralisation

    NASA Astrophysics Data System (ADS)

    Zamanian, Hassan; Radmard, Kaikosrov

    2016-03-01

    The Baba Ali skarn deposit, situated 39 km to the northwest of Hamadan (Iran), is the result of a syenitic pluton that intruded and metamorphosed the diorite host rock. Rare earth element (REE) values in the quartz syenite and diorite range between 35.4 and 560 ppm. Although the distribution pattern of REEs is more and less flat and smooth, light REEs (LREEs) in general show higher concentrations than heavy REEs (HREEs) in different lithounits. The skarn zone reveals the highest REE-enriched pattern, while the ore zone shows the maximum depletion pattern. A comparison of the concentration variations of LREEs (La-Nd), middle REEs (MREEs; Sm-Ho) and HREEs (Er-Lu) of the ore zone samples to the other zones elucidates two important points for the distribution of REEs: 1) the distribution patterns of LREEs and MREEs show a distinct depletion in the ore zone while representing a great enrichment in the skarn facies neighbouring the ore body border and decreasing towards the altered diorite host rock; 2) HREEs show the same pattern, but in the exoskarn do not reveal any distinct increase as observed for LREEs and MREEs. The ratio of La/Y in the Baba Ali skarn ranges from 0.37 to 2.89. The ore zone has the highest La/Y ratio. In this regard the skarn zones exhibit two distinctive portions: 1) one that has La/Y >1 beingadjacent to the ore body and; 2) another one with La/Y < 1 neighbouring altered diorite. Accordingly, the Baba Ali profile, from the quartz syenite to the middle part of the exoskarn, demonstrates chiefly alkaline conditions of formation, with a gradual change to acidic towards the altered diorite host rocks. Utilising three parameters, Ce/Ce*, Eu/Eu* and (Pr/Yb)n, in different minerals implies that the hydrothermal fluids responsible for epidote and garnet were mostly of magmatic origin and for magnetite, actinolite and phlogopite these were of magmatic origin with low REE concentration or meteoric water involved.

  10. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes

    NASA Astrophysics Data System (ADS)

    Tuttle, Michele L.; Goldhaber, Martin B.

    1993-07-01

    The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and δ 34S values, and long-term evolutionary trends in δ 34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (S Av), disulfide (S Di > 70% of total sulfur), sulfate (S SO4) and organosulfur (S Org); isotopic composition of separated sulfur phases (δ 34S Di,Av up to +49‰); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, δ 34S Di,Av, and δ 34S Org have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H 2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H 2S:SO 4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H 2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to δ 34S values much greater than that of inflow sulfate, which is

  11. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagnetic processes in saline alkaline lakes

    SciTech Connect

    Tuttle, M.L.; Goldhaber, M.B. )

    1993-07-01

    The sulfur geochemistry of the lacustrine Paleogene Green River Formation is unlike that of most marine and lacustrine rocks. Chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides enriched in [sup 34]S, cyclical trends in sulfur abundance and [delta][sup 34]S values, and long-term evolutionary trends in [delta][sup 34]S values. Mineralogy, morphology, [delta][sup 34]S[sub Di,Av], and [delta][sup 34]S[sub Org] have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H[sub 2]S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H[sub 2]S:SO[sub 4] ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H[sub 2]S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to [delta][sup 34]S values much greater than that of inflow sulfate, which is estimated to have been +20[per thousand]. A six-million-year interval within Lake Uinta cores records this evolution as well as smaller systematic changes in [delta][sub 34]S, interpreted to reflect [approximately]100,000-year lake-level cycles. When porewater was exceptionally reducing, unstable FeS phases eventually recrystallized to pyrrhotite during diagenesis. A later reaction altered pyrrhotite to marcasite. 96 refs., 10 figs., 1 tab.

  12. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes

    USGS Publications Warehouse

    Tuttle, M.L.; Goldhaber, M.B.

    1993-01-01

    The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and ??34S values, and long-term evolutionary trends in ??34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (SAv), disulfide (SDi > 70% of total sulfur), sulfate (SSO4) and organosulfur (SOrg); isotopic composition of separated sulfur phases (??34SDi,Av up to +49???); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, ??34SDi,Av, and ??34SOrg have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H2S:SO4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to ??34S values much greater than that of inflow sulfate, which is estimated to have

  13. Natural Hazard Public Policy Implications of the May 12, 2008 M7.9 Wenchuan Earthquake, Sichuan, China

    NASA Astrophysics Data System (ADS)

    Cydzik, K.; Hamilton, D.; Stenner, H. D.; Cattarossi, A.; Shrestha, P. L.

    2009-12-01

    The May 12, 2008 M7.9 Wenchuan Earthquake in Sichuan Province, China killed almost 90,000 people and affected a population of over 45.5 million throughout western China. Shaking caused the destruction of five million buildings, many of them homes and schools, and damaged 21 million other structures, inflicting devastating impacts to communities. Landslides, a secondary effect of the shaking, caused much of the devastation. Debris flows buried schools and homes, rock falls crushed cars, and rockslides, landslides, and rock avalanches blocked streams and rivers creating massive, unstable landslide dams, which formed “quake lakes” upstream of the blockages. Impassable roads made emergency access slow and extremely difficult. Collapses of buildings and structures large and small took the lives of many. Damage to infrastructure impaired communication, cut off water supplies and electricity, and put authorities on high alert as the integrity of large engineered dams were reviewed. During our field reconnaissance three months after the disaster, evidence of the extent of the tragedy was undeniably apparent. Observing the damage throughout Sichuan reminded us that earthquakes in the United States and throughout the world routinely cause widespread damage and destruction to lives, property, and infrastructure. The focus of this poster is to present observations and findings based on our field reconnaissance regarding the scale of earthquake destruction with respect to slope failures, landslide dams, damage to infrastructure (e.g., schools, engineered dams, buildings, roads, rail lines, and water resources facilities), human habitation within the region, and the mitigation and response effort to this catastrophe. This is presented in the context of the policy measures that could be developed to reduce risks of similar catastrophes. The rapid response of the Chinese government and the mobilization of the Chinese People’s Liberation Army to help the communities affected

  14. [Inventory and environmental impact of VOCs emission from the typical anthropogenic sources in Sichuan province].

    PubMed

    Han, Li; Wang, Xing-Rui; He, Min; Guo, Wei-Guang

    2013-12-01

    Based on Sichuan province environmental statistical survey data and other relevant activity data, volatile organic compounds (VOCs) emissions from typical anthropogenic sources in Sichuan province were calculated for the year of 2011 by applying the emission factor method. Besides, ozone and secondary organic aerosol formation potentials of these typical anthropogenic sources were discussed. The total VOC emission from these sources was about 482 kt in Sichuan province, biomass burning, solvent utilization, industrial processes, storage and distribution of fuel, and fossil fuel combustion contributed 174 kt, 153 kt, 121 kt, 21 kt and 13 kt, respectively; architecture wall painting, furniture coating, wood decoration painting and artificial board were the major emission sectors of the solvent utilization; while for the industrial processes, 19.4% of VOCs emission was from the wine industry. Chengdu was the largest contributor compared to the other cities in Sichuan, whose VOCs emission from these typical anthropogenic sources in 2011 was 112 kt. OFP of these sources was 1,930 kt altogether. Solvent utilization contributed 50.5% of the total SOA formation potentials, biomass burning and industrial processes both contributed about 23% , with storage and distribution of fuel and fossil fuel combustion accounting for 1% and 1.4%, respectively. PMID:24640887

  15. Left-Behind Children in Rural Primary Schools: The Case of Sichuan Province

    ERIC Educational Resources Information Center

    Liang, Wenyan; Hou, Longlong; Chen, Wentao

    2008-01-01

    During China's economic transformation, much of the rural population migrated to urban areas in search of employment opportunities. "Left-behind children" are the product of this phenomenon and need significant attention. Our study adopted elementary school students in Sichuan province as the subjects. After carefully studying their academic…

  16. Epidemiology of human hookworm infections among adult villagers in Hejiang and Santai Counties, Sichuan Province, China.

    PubMed

    Changhua, L; Xiaorong, Z; Dongchuan, Q; Shuhua, X; Hotez, P J; Defu, Z; Hulian, Z; Mingden, L; Hainan, R; Bing, Z; Haichou, X; Hawdon, J; Zheng, F

    1999-10-15

    Hookworm infection as well as other intestinal nematodiases are endemic to Sichuan Province in China. In order to research the prevalence and intensity of these infections we visited two villages in Hejiang County (southern Sichuan Province) and Santai County (northwestern Sichuan Province) between July and October of 1997. Fecal examinations were performed on adult villagers over the age of 15 years (currently children under this age are dewormed annually with anthelmintic drugs). Among 310 residents of Lugao Village (Hejiang County), 87, 63 and 60% were infected with hookworm, Ascaris or Trichuris, respectively. The prevalence of hookworm determined to rise linearly with age (r = 0.97). High intensity infections with hookworm still occur in this region as 22% of the residents have over 3000 eggs per gram (PEG) of feces as determined by quantitative egg counts. The majority of these individuals harbored mixed infection with Necator americanus and Ancylostoma duodenale, although the former predominated when adult hookworms were collected from 30 village residents treated with pyrantel pamoate. In contrast, among the 334 Xinjian villagers examined (Santai County) the majority harbored predominantly light hookworm infections--66.1% of the residents has less than 400 EPG by quantitative fecal examination and only 3.7% exhibited greater than 3000 EPG. Again, N. americanus was the predominant hookworm seen after worm expulsion. We have round that despite economic development which is occurring in some parts of China, significant hookworm infections and clinical hookworm anemia still exist in areas of Sichuan Province. In Hejiang County we found that the intensity of hookworm infection has actually risen within the last 10 years. Hookworm is a medical problem among the elderly in Sichuan. PMID:10546842

  17. Petrogenesis of the Yaochong granite and Mo deposit, Western Dabie orogen, eastern-central China: Constraints from zircon U-Pb and molybdenite Re-Os ages, whole-rock geochemistry and Sr-Nd-Pb-Hf isotopes

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Xu, Zhaowen; Qiu, Wenhong; Li, Chao; Yu, Yang; Wang, Hao; Su, Yang

    2015-05-01

    The Dabie orogen is among the most famous continent-continent collisional orogenic belts in the world, and is characterized by intensive post-collisional extension, magmatism and Mo mineralization. However, the genetic links between the mineralization and the geodynamic evolution of the orogen remain unresolved. In this paper, the Yaochong Mo deposit and its associated granitic stocks were investigated to elucidate this issue. Our new zircon U-Pb ages yielded an Early Cretaceous age (133.3 ± 1.3 Ma) for the Yaochong granite, and our molybdenite Re-Os dating gave a similar age (135 ± 1 Ma) for the Mo deposit. The Yaochong stock is characterized by high silica and alkali but low Mg, Fe and Ca. It is enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs: Rb, K, Th and U), but strongly depleted in heavy REEs, and high field strength elements (HFSEs: Nb, Ta, Ti and Y). The Yaochong granite has initial 87Sr/86Sr ratios of 0.7087-0.7096, and Pb isotopic ratios of (206Pb/204Pb)i = 16.599-16.704, (207Pb/204Pb)i = 15.170-15.618 and (208Pb/204Pb)i = 36.376-38.248. The granite has εNd(t) of -18.0 to -16.3 and εHf(t) values of -26.5 to -20.0. All these data indicate that the Yaochong granite is a high-K calc-alkaline fractionated I-type granite, and may have originated from partial melting of the thickened Yangtze continental crust. The Mo ores also show low radiogenic Pb isotopes similar to the Yaochong stock. Medium Re content in molybdenite (21.8-74.8 ppm) also suggests that the ore-forming materials were derived from the thickened lower crust with possibly minor mixing with the mantle. Similar to the Eastern Dabie orogen, the thickened crust beneath the Western Dabie orogen may also have experienced tectonic collapse, which may have exerted fundamental geodynamic controls on the two-stage Mo mineralization in the region.

  18. Determination of (226)Ra, (232)Th, (40)K, (235)U and (238)U activity concentration and public dose assessment in soil samples from bauxite core deposits in Western Cameroon.

    PubMed

    Mekongtso Nguelem, Eric Jilbert; Moyo Ndontchueng, Maurice; Motapon, Ousmanou

    2016-01-01

    Determination of activity concentrations in twenty five (25) soil samples collected from various points in bauxite ore deposit in Menoua Division in Western of Cameroon was done using gamma spectrometry based Broad Energy Germanium (BEGe6530) detector. The average terrestrial radionuclides of (40)K, (226)Ra, (232)Th, (235)U and (238)U were measured as 671 ± 272, 125 ± 58, 157 ± 67, 6 ± 3 and 99 ± 69 Bq kg(-1), respectively. The observed activity concentrations of radionuclides were compared with other published values in the world. The outdoor absorbed dose rate in air varied from 96.1 to 321.2 nGy h(-1) with an average of 188.2 ± 59.4 nGy h(-1). The external annual effective dose rate and external hazard index were estimated as 0.23 ± 0.07 mSv year(-1) for outdoor, 0.92 ± 0.29 mSv year(-1) for indoor and 1.13 for the external hazard index, respectively. These radiological safe parameters were relatively higher than the recommended safe limits of UNSCEAR. Consequently, using of soil as building material might lead to an increase the external exposure to natural radioactivity and future applications research need to be conducted to have a global view of radioactivity level in the area before any undergoing bauxite ore exploitation. PMID:27536536

  19. Western USA

    Atmospheric Science Data Center

    2014-05-15

    article title:  Western United States Beyond the Four Corners ... to examine Earth's land, oceans, atmosphere, ice, and life as a total integrated system. MISR was built and is managed by NASA's ... D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. The MISR data were obtained from the NASA ...

  20. Natural and artificial radionuclide measurements and radioactivity assessment of soil samples in eastern Sichuan province (China).

    PubMed

    Wang, Zhonghai; He, Jun; Du, Yu; He, Yang; Li, Zhiqian; Chen, Zhihua; Yang, Chaowen

    2012-07-01

    The activity concentrations of natural and artificial radionuclides were measured in the eastern region of Sichuan province (China). One hundred and ninety-three soil samples from this region were collected and analysed by high-purity germanium gamma spectrometry. The measured results show that the average radioactivity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in the soil samples are 26, 49, 440 and 6 Bq kg(-1), respectively. The calculated average radium equivalent activity is 130 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1). The absorbed dose rate and annual effective dose are 60 nGy h(-1) and 74 µSv, respectively. This is the first time the absorbed dose rate in the east region of Sichuan has been mapped. Overall, the environmental radiation background is greater in the southern part of the area studied than in the northern. PMID:22128351

  1. [A survey of nutrition knowledge-attitudes-practices of Sichuan urban and rural adults].

    PubMed

    Zhang, Y P; Guldan, G S; Li, Z Q

    1993-01-01

    To provide a basis for designing nutrition education, two nutrition knowledge--attitudes--practices (KAP) surveys of adults aged 18 to 55 were conducted in 1989 in an urban (N = 1004) and a rural (N = 506) area of Sichuan. The results indicated that the nutrition levels in both sites were low, and an awareness of the relationship between nutrition and certain common diseases was lacking. However, both urban and rural adults possessed good attitudes toward nutrition and nutrition education. Large differences existed between urban and rural adults' food patterns, with the rural diet more monotonous than the urban one. The rural women will be a hard-to-reach audience requiring more intensive efforts. The findings suggest that nutrition education efforts for Sichuan urban and rural area adults will require different contents and emphases, different methods of delivery, and language suitable for each group, in order to obtain good results. PMID:8325173

  2. Preliminary investigation of some large landslides triggered by the 2008 Wenchuan earthquake, Sichuan Province, China

    USGS Publications Warehouse

    Wang, F.; Cheng, Q.; Highland, L.; Miyajima, M.; Wang, Hongfang; Yan, C.

    2009-01-01

    The M s 8.0 Wenchuan earthquake or "Great Sichuan Earthquake" occurred at 14:28 p.m. local time on 12 May 2008 in Sichuan Province, China. Damage by earthquake-induced landslides was an important part of the total earthquake damage. This report presents preliminary observations on the Hongyan Resort slide located southwest of the main epicenter, shallow mountain surface failures in Xuankou village of Yingxiu Town, the Jiufengchun slide near Longmenshan Town, the Hongsong Hydro-power Station slide near Hongbai Town, the Xiaojiaqiao slide in Chaping Town, two landslides in Beichuan County-town which destroyed a large part of the town, and the Donghekou and Shibangou slides in Qingchuan County which formed the second biggest landslide lake formed in this earthquake. The influences of seismic, topographic, geologic, and hydro-geologic conditions are discussed. ?? 2009 Springer-Verlag.

  3. Molecular epidemiology of Porcine torovirus (PToV) in Sichuan Province, China: 2011–2013

    PubMed Central

    2014-01-01

    Background Porcine torovirus (PToV) is a member of the genus Torovirus which is responsible for gastrointestinal disease in both human beings and animals with particular prevalence in youth. Torovirus infections are generally asymptomatic, however, their presence may worsen disease consequences in concurrent infections with other enteric pathogens. Methods A total of 872 diarrheic fecal samples from pigs of different ages were collected from 12 districts of Sichuan Province in the southwest of China. RT-PCR was done with PToV S gene specific primers to detect the presence of PToV positive samples. M gene specific primers were used with the PToV positive samples and the genes were sequenced. A phylogenetic tree was constructed based on the M gene nucleotide sequences from the 19 selected novel Sichuan strains and 21 PToV and BToV M gene sequences from GenBank. Results A total of 331 (37.96%, 331/872) samples were found to be positive for PToV and the highest prevalence was observed in piglets aged from 1 to 3 weeks old. Through phylogenetic inference the 40 PToV M gene containing sequences were placed into two genotypes (I & II). The 19 novel Sichuan strains of genotype I showed strong correlations to two Korean gene sequences (GU-07-56-11 and GU-07-56-22). Amino-acid sequence analysis of the 40 PToV M gene strains revealed that the M gene protein was highly conserved. Conclusions This study uncovered the presence of PToV in Sichuan Province, and demonstrated the need for continuous surveillance PToV of epidemiology. PMID:24903213

  4. Salt-related tectonics in the eastern Sichuan Basin, South China

    NASA Astrophysics Data System (ADS)

    Gu, Zhidong; Yin, Jifeng; Yuan, Miao; Zhai, Xiufen

    2015-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze platform of South China, and East Sichuan is situated between Huaying Mountain fault and Qiyue Mountain fault. The surface Jura type folds are very famous with barrier parallel folds, but the cause of folds formation have not been completely understood. Stratigraphic units are composed of thick competent flexural layers separately by relatively thin incompetent ductile layers that can act as detachments.Multiple detachment layers are developed in the eastern Sichuan and result in distinct structural domains. In addition to the basal, Triassic and Silurian system detachment layers, we recognize a regionally extensive salt layer in the Middle and Lower Cambrian. The recognition of salt layer is by the synthetical studies of outcrop, drilling well, and chaotic seismic reflection configuration. The Middle and Lower Cambrian salt forms a tectonic domain boundary that can be observed by seismic reflection profile in subsurface. The stratigraphic intervals above and below the salt develop characteristic salt-related tectonics. And the folds formation is by flow in and flow out of salt movement of the Middle and Lower Cambrian and flexural slip and grouding of the overlying units. Above the salt, the thrust fault-related folds were generated by the contractional action from southeast to northwest, including the fault-bend fold, fault-propagation fold, and thrust wedge fold, and so on. Below the salt, the broad anticlines were formed due to the basal detachment. Hydrocarbon traps are formed above and below the salt, and they are potential gas exploration domains in the eastern Sichuan Basin.

  5. Rapid sea-level change in the Late Guadalupian (Permian) on the Tethyan side of South China: litho- and biostratigraphy of the Chaotian section in Sichuan

    PubMed Central

    Isozaki, Yukio; Yao, Jianxin; Ji, Zhangshen; Saitoh, Masafumi; Kobayashi, Noritada; Sakai, Harutaka

    2008-01-01

    The Capitanian (Late Guadalupian) Maokou Formation at Chaotian in northern Sichuan, South China, is composed mainly of shallow marine shelf carbonates deposited on the Tethyan side of South China. By detailed field mapping and scientific drilling, we newly found out unique fossil assemblages and a sharp lithologic change in the upper part of the Maokou Formation. The main part of the Maokou Formation (over 130 m thick) is composed of algal packstone with Wordian-Capitanian large-tested fusulines, rugose corals and other sessile benthos, whereas the Uppermost Member (13 m thick) is composed of black limy mudstone/chert with Capitanian offshore biota (ammonoids, radiolarians, and conodonts). The topmost Capitanian conodont zones are missing; however, the Maokou Formation is disconformably overlain by 260 ± 4 Ma volcanic ash (Wangpo bed) and the Early Lopingian Wujiaping Formation with plant-bearing coaly mudstone and shallow marine carbonates (packstone). The newly identified facies change indicates that northern Sichuan has experienced rapid sea-level changes in the late Guadalupian, i.e., first a transgression in the mid-Capitanian and then a regression across the Guadalupian-Lopingian boundary. As the end-Guadalupian is characterized by a global regression, such a volatile sea-level fluctuation, in particular the sea-level rise, is unique to the Tethyan side of South China. The newly recognized relatively deep-water late Guadalupian sequence adds new paleo-environmental information and further provides a paleotectonic interpretation of the low-latitude eastern Tethyan margin immediately before the end-Guadalupian mass extinction. PMID:18941307

  6. Molecular Epidemiology of Porcine Cytomegalovirus (PCMV) in Sichuan Province, China: 2010–2012

    PubMed Central

    Xu, Zhiwen; Zhou, Yuancheng

    2013-01-01

    Porcine cytomegalovirus (PCMV) is an immunosuppressive virus that mainly inhibits the immune function of the macrophage and T-cell lymphatic systems, and has caused huge economic losses to the porcine breeding industry. Molecular epidemiological investigation of PCMV is important for prevention and treatment, and this study is the first such investigation in Sichuan Province, Southwest China. A PCMV positive infection rate of 84.4% (865/1025) confirmed that PCMV is widely distributed in Sichuan Province. A phylogenetic tree was constructed based on the PCMV glycoprotein B gene (gB) nucleotide and amino acid sequences from 24 novel Sichuan isolates and 18 other PCMV gB sequences from Genbank. PCMV does not appear to have evolved into different serotypes, and two distinct sequence groups were identified (A and B). However, whether PCMV from this region has evolved into different genotypes requires further research. Analysis of the amino acid sequences confirmed the conservation of gB, but amino acid substitutions in the major epitope region have caused antigenic drift, which may have altered the immunogenicity of PCMV. PMID:23762243

  7. Production of hybrids between western gray wolves and western coyotes

    USGS Publications Warehouse

    Mech, L. David; Christensen, Bruce W.; Asa, Cheryl S.; Callahan, Magaret; Young, Julie K.

    2014-01-01

    Using artificial insemination we attempted to produce hybrids between captive, male, western, gray wolves (Canis lupus) and female, western coyotes (Canis latrans) to determine whether their gametes would be compatible and the coyotes could produce and nurture offspring. The results contribute new information to an ongoing controversy over whether the eastern wolf (Canis lycaon) is a valid unique species that could be subject to the U. S. Endangered Species Act. Attempts with transcervically deposited wolf semen into nine coyotes over two breeding seasons yielded three coyote pregnancies. One coyote ate her pups, another produced a resorbed fetus and a dead fetus by C-section, and the third produced seven hybrids, six of which survived. These results show that, although it might be unlikely for male western wolves to successfully produce offspring with female western coyotes under natural conditions, western-gray-wolf sperm are compatible with western-coyote ova and that at least one coyote could produce and nurture hybrid offspring. This finding in turn demonstrates that gamete incompatibility would not have prevented western, gray wolves from inseminating western coyotes and thus producing hybrids with coyote mtDNA, a claim that counters the view that the eastern wolf is a separate species. However, some of the difficulties experienced by the other inseminated coyotes tend to temper that finding and suggest that more experimentation is needed, including determining the behavioral and physical compatibility of western gray wolves copulating with western coyotes. Thus although our study adds new information to the controversy, it does not settle it. Further study is needed to determine whether the putative Canis lycaon is indeed a unique species.

  8. Production of hybrids between western gray wolves and western coyotes.

    PubMed

    Mech, L David; Christensen, Bruce W; Asa, Cheryl S; Callahan, Margaret; Young, Julie K

    2014-01-01

    Using artificial insemination we attempted to produce hybrids between captive, male, western, gray wolves (Canis lupus) and female, western coyotes (Canis latrans) to determine whether their gametes would be compatible and the coyotes could produce and nurture offspring. The results contribute new information to an ongoing controversy over whether the eastern wolf (Canis lycaon) is a valid unique species that could be subject to the U. S. Endangered Species Act. Attempts with transcervically deposited wolf semen into nine coyotes over two breeding seasons yielded three coyote pregnancies. One coyote ate her pups, another produced a resorbed fetus and a dead fetus by C-section, and the third produced seven hybrids, six of which survived. These results show that, although it might be unlikely for male western wolves to successfully produce offspring with female western coyotes under natural conditions, western-gray-wolf sperm are compatible with western-coyote ova and that at least one coyote could produce and nurture hybrid offspring. This finding in turn demonstrates that gamete incompatibility would not have prevented western, gray wolves from inseminating western coyotes and thus producing hybrids with coyote mtDNA, a claim that counters the view that the eastern wolf is a separate species. However, some of the difficulties experienced by the other inseminated coyotes tend to temper that finding and suggest that more experimentation is needed, including determining the behavioral and physical compatibility of western gray wolves copulating with western coyotes. Thus although our study adds new information to the controversy, it does not settle it. Further study is needed to determine whether the putative Canis lycaon is indeed a unique species. PMID:24586418

  9. Production of Hybrids between Western Gray Wolves and Western Coyotes

    PubMed Central

    Mech, L. David; Christensen, Bruce W.; Asa, Cheryl S.; Callahan, Margaret; Young, Julie K.

    2014-01-01

    Using artificial insemination we attempted to produce hybrids between captive, male, western, gray wolves (Canis lupus) and female, western coyotes (Canis latrans) to determine whether their gametes would be compatible and the coyotes could produce and nurture offspring. The results contribute new information to an ongoing controversy over whether the eastern wolf (Canis lycaon) is a valid unique species that could be subject to the U. S. Endangered Species Act. Attempts with transcervically deposited wolf semen into nine coyotes over two breeding seasons yielded three coyote pregnancies. One coyote ate her pups, another produced a resorbed fetus and a dead fetus by C-section, and the third produced seven hybrids, six of which survived. These results show that, although it might be unlikely for male western wolves to successfully produce offspring with female western coyotes under natural conditions, western-gray-wolf sperm are compatible with western-coyote ova and that at least one coyote could produce and nurture hybrid offspring. This finding in turn demonstrates that gamete incompatibility would not have prevented western, gray wolves from inseminating western coyotes and thus producing hybrids with coyote mtDNA, a claim that counters the view that the eastern wolf is a separate species. However, some of the difficulties experienced by the other inseminated coyotes tend to temper that finding and suggest that more experimentation is needed, including determining the behavioral and physical compatibility of western gray wolves copulating with western coyotes. Thus although our study adds new information to the controversy, it does not settle it. Further study is needed to determine whether the putative Canis lycaon is indeed a unique species. PMID:24586418

  10. Western Canada

    SciTech Connect

    Hay, P.W.; Robertson, D.C.

    1981-10-01

    In 1980, a third successive all-time drilling record was set in western Canada, with 8865 wells being drilled, up 20% since 1979. Exploratory drilling increased 30%, to 3744 wells, and development drilling increased 14%, to 5121 wells. The exploratory success rate increased to 66% in 1980, based on 1017 oil discoveries and 1463 gas discoveries. The development success rate increased marginally to 89%, with 1774 oil discoveries and 2778 gas discoveries. Average well depth increased in all four western provinces, and total land sales reached the record $1 billion mark in Alberta and a record $78 million in Saskatchewan. British Columbia land sales declined slightly to $181 million. Alberta drilling activity continued in the deeper portions of the Alberta basin and foothills, with major gas discoveries at Hanlan, Big Mountain, Blackstone, and Elmworth. Significant oil discoveries were made in the West Pembina Nisku pinnacle reefs, in the Upper Devonian at Del Bonita and Eaglesham, and in the Lower Cretaceous glauconite river channels in southern Alberta between Countess and Grand Forks. British Columbia successes occurred as the Elmworth Deep Basin play spilled over into British Columbia with gas discoveries at Tupper and Steeprock. Gas finds were also made at West Sierra and Murray. The Arctic Islands continued to yield the largest discoveries. Two major successes occurred in the Beaufort Sea, in an oil and gas discovery by Esso at Issungnak and a reentry oil discovery by Dome at Tarsuit. However, 1980 will especially be remembered for the introduction of the federal government's National Energy Program during October, with new taxes on revenue, lower than expected wellhead price increases, and major emphasis on increasing Canadian ownership and self-sufficiency. Industry and provincial government reaction was highly critical, and a major downturn in exploration is expected in western Canada in 1981. 3 figures, 8 tables.

  11. Western Conifers Research Cooperative 1987 research plan

    SciTech Connect

    Olson, R.K.

    1987-08-01

    The Western Conifers Research Cooperative is part of the national Forest Response Program (FRP). The FRP is a federal program designed to determine the current and potential effects of atmospheric deposition on forests in the United States. Research is conducted regionally within four research Cooperatives. The Western Cooperative is concerned with the effects of atmospheric deposition on coniferous forests in the eleven conterminous western states. The 1987 Research Plan first outlines the objectives and research strategy of the FRP. The objectives and strategy of the Western Cooperative are then described in the context of the parent organization. The 1986 Western Cooperative program is reviewed followed by a description of the 1987 program. Brief descriptions of each of the individual 1987 research projects are also given.

  12. Chemical characteristics of rainwater in Sichuan basin, a case study of Ya'an.

    PubMed

    Li, Yun-Chun; Zhang, Meng; Shu, Man; Ho, Steven Sai Hang; Liu, Zi-Fang; Wang, Xian-Xiang; Zhao, Xiao-Qing

    2016-07-01

    Rainwater chemistry was investigated at a semi-rural site in Ya'an, Sichuan basin with rain samples collected from May 2013 to July 2014. The rainwater pH values ranged from 3.25 to 6.86, with an annual volume-weighted mean (VWM) of 4.38, and the acid rain frequency was 74 %. Such severe acidification, 15 % of the total events showed a pH below 4.0, attributed to the deficiency of Ca(2+), significant anthropogenic pollution contribution, and rainy pattern to this area. The annual VWM of total ions concentration was 477.19 μeq/L. NH4 (+) was the most abundant ionic species, followed by SO4 (2-), NO3 (-), Ca(2+), Cl(-), Na(+), K(+), Mg(2+), and F(-) in a descending order. The total ionic concentrations presented a seasonal trend of lower values in autumn and summer but higher ones in winter and spring. Based on enrichment factor, correlation analysis and principle component analysis, three factors were identified: factor 1 (NH4 (+), SO4 (2-), NO3 (-), K(+), and Cl(-), 47.45 % of the total variance) related to anthropogenic sources (coal/fuel combustion, biomass burning and agriculture), factor 2 (Ca(2+), Mg(2+), Na(+), and Cl(-), 34.01 % of the total variance) associated with natural sources, and factor 3 (H(+), 11.78 % of the total variance) related to free acidity. Back trajectory analysis indicates that the rainwater chemistry in Ya'an was mainly affected by regional air masses from Sichuan basin. Long-range transported air masses from southwest with heavy anthropogenic pollution increased the total ion concentration and acidity of rainwater. Considering its special topography, anthropogenic emissions from regional and long-range transport (especially from southwest) must be controlled effectively to improve the acid rain condition of non-urban areas in Sichuan basin. PMID:27000115

  13. The evolution of eastern Sichuan basin, Yangtze block since Cretaceous: Constraints from low temperature thermochronology

    NASA Astrophysics Data System (ADS)

    Shi, Hongcai; Shi, Xiaobin; Glasmacher, Ulrich A.; Yang, Xiaoqiu; Stockli, Daniel F.

    2016-02-01

    In Yangtze block (South China), there is a well-developed Mesozoic thrust system extended through the Xuefeng and Wuling mountains in the southeast to the Sichuan basin in the northwest. We present 11 apatite fission-track (AFT) data and 11 (U-Th-Sm)/He ages to unravel the low temperature thermal history of a part of the system located in the eastern Sichuan basin. The fission-track data are interpreted using a grain-age deconvolution algorithm with inverse thermal modeling of track length, grain ages and mineral composition proxy data. Results suggest that apatite fission-track ages range between 99.3 ± 8.1 and 51.0 ± 4.0 Ma, and the apatite (U-Th-Sm)/He ages between 58.3 ± 3.5 Ma and 14.2 ± 0.9. The spatial distribution of these ages shows a trend decreased from SE to NW gradually, which supports the idea of a prolonged, steady-state rock uplift and erosion process across the eastern Sichuan basin. Thermal history modeling of the combined FT and (U-Th-Sm)/He datasets reveal a common three stage cooling history: (1) initial stage of rapid cooling that younger to the east during pre-Cretaceous, (2) following by a period of relative (but not perfect) thermal stability at ∼65-50 °C, (3) and then a new rapid cooling stage that initiated in all samples between ∼15 and 20 Ma. The first rapid cooling at a rate of ⩾1.5 °C/Ma is associated with coeval tectonism in nearby regions, which result in folds and faults of the eastern Sichuan basin. Early-mid Cenozoic thermal stability is contributed to the extension widely occurring in the eastern China continent at which the average cooling rate decreased to ∼0.16 °C/Ma. Causes for speculative accelerated cooling after ca. 20-15 Ma with a rate of ⩾1.2 °C/Ma may be a far-field effect of upward and eastward growth of the Tibetan Plateau but could also be related to climate effects. In a whole, this paper analyzes the several Mesozoic and Cenozoic tectonic events influence to the patters of regional denudation.

  14. A new species of Triplophysa Rendahl (Cypriniformes, Nemacheilidae) from Sichuan Province, China

    PubMed Central

    YAN, Si-Li; SUN, Zhi-Yu; GUO, Yan-Shu

    2015-01-01

    Triplophysa yajiangensis sp. nov. is described from the upper and middle reaches of the Yalong River, Yangtze Basin, Ganzi Prefecture, Sichuan Province, China. This new species can be distinguished from other congeneric species by the following characters: body surface smooth and scaleless; lateral line complete; caudal peduncle compressed and tapered slightly; lower jaw shovel-shaped; head shorter than caudal peduncle; dorsal-fin origin anterior to pelvic-fin origin and closer to tip of snout than to caudal-fin base, last unbranched ray hard; pelvic-fin reaches or exceeds anus; posterior chamber of gas bladder absent; intestine spiral type with 3-5 winding coils. PMID:26452694

  15. [Formation of popular medical books in Sichuan Province in late Qing Dynasty and its influence].

    PubMed

    He, Z

    1994-01-01

    Among the traditional Chinese medical works in the Qing Dynasty is Sichuan province, popular ones occupied the major part. This author investigates its causes from the angles of economics, population and characteristics of physicians in this province. He also discusses the abridgement or re-compilation on the basis of those authors by their own clinical experience, who either imitated the stkyle, recompiled, or even attached their own work to Chen Xiuyuan's medical books. The influence, significance and role of these medical books are also mentioned. PMID:11615222

  16. A new species of Triplophysa Rendahl (Cypriniformes, Nemacheilidae) from Sichuan Province, China.

    PubMed

    Yan, Si-Li; Sun, Zhi-Yu; Guo, Yan-Shu

    2015-09-18

    Triplophysa yajiangensis sp. nov. is described from the upper and middle reaches of the Yalong River, Yangtze Basin, Ganzi Prefecture, Sichuan Province, China. This new species can be distinguished from other congeneric species by the following characters: body surface smooth and scaleless; lateral line complete; caudal peduncle compressed and tapered slightly; lower jaw shovel-shaped; head shorter than caudal peduncle; dorsal-fin origin anterior to pelvic-fin origin and closer to tip of snout than to caudal-fin base, last unbranched ray hard; pelvic-fin reaches or exceeds anus; posterior chamber of gas bladder absent; intestine spiral type with 3-5 winding coils. PMID:26452694

  17. Co-seismic ruptures of the 12 May 2008, Ms 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet

    USGS Publications Warehouse

    Liu-Zeng, J.; Zhang, Z.; Wen, L.; Tapponnier, P.; Sun, Jielun; Xing, X.; Hu, G.; Xu, Q.; Zeng, L.; Ding, L.; Ji, C.; Hudnut, K.W.; van der Woerd, J.

    2009-01-01

    The Ms 8.0, Wenchuan earthquake, which devastated the mountainous western rim of the Sichuan basin in central China, produced a surface rupture over 200??km-long with oblique thrust/dextral slip and maximum scarp heights of ~ 10??m. It thus ranks as one of the world's largest continental mega-thrust events in the last 150??yrs. Field investigation shows clear surface breaks along two of the main branches of the NE-trending Longmen Shan thrust fault system. The principal rupture, on the NW-dipping Beichuan fault, displays nearly equal amounts of thrust and right-lateral slip. Basin-ward of this rupture, another continuous surface break is observed for over 70??km on the parallel, more shallowly NW-dipping Pengguan fault. Slip on this latter fault was pure thrusting, with a maximum scarp height of ~ 3.5??m. This is one of the very few reported instances of crustal-scale co-seismic slip partitioning on parallel thrusts. This out-of-sequence event, with distributed surface breaks on crustal mega-thrusts, highlights regional, ~ EW-directed, present day crustal shortening oblique to the Longmen Shan margin of Tibet. The long rupture and large offsets with strong horizontal shortening that characterize the Wenchuan earthquake herald a re-evaluation of tectonic models anticipating little or no active shortening of the upper crust along this edge of the plateau, and require a re-assessment of seismic hazard along potentially under-rated active faults across the densely populated western Sichuan basin and mountains. ?? 2009 Elsevier B.V.

  18. Séquences de dépôt à l'articulation plate-forme urgonienne bassin (intervalle Barrémien Albien) dans le Prébalkan occidental (Bulgarie du Nord-Ouest)Depositional sequences at the Urgonian platform/basin transition (Barremian Albian interval) in the western Fore-Balkan (northwest Bulgaria).

    NASA Astrophysics Data System (ADS)

    Peybernès, Bernard; Ivanov, Marin; Nikolov, Todor; Ciszak, Richard; Stoykova, Kristalina

    2000-04-01

    In the western Fore-Balkan (northwest Bulgaria), the characterization of numerous depositional sequences within the Barremian-Albian interval allows us to reconstruct from southeast to northwest the successive palaeogeographies of this part of the north Tethyan margin: two carbonate (Urgonian) platforms flanking a central terrigenous basin during the Barremian; a single centrifugal terrigenous basin (Aptian) marked, along its axis, by an olistostrome and siliciclastic turbidites; a single Albian basin characterized by the stacking of glauconite-rich condensation sections and anoxic black marls.

  19. Western Gas Sands Subprogram

    SciTech Connect

    Not Available

    1983-12-01

    The Western Gas Sands Subprogram (WGSS) is a multidisciplinary research effort within the US Department of Energy program on Unconventional Gas Recovery. The subprogram, managed by DOE's Morgantown Energy Technology Center, is directed towards the development of tight (very low permeability) lenticular gas sands in the western United States. The purpose of the subprogram is to demonstrate the feasibility of economically producing natural gas from low-permeability reservoirs. The subprogram has two broad goals: (1) to reduce the uncertainty of the reservoir production potential and (2) to improve the extraction technology. With input from the gas industry, universities, and geologic and engineering consulting firms, the WGSS was broadened to include more fundamental research and development. Consequently, for the last five years it has focused on improving diagnostic instrumentation, geophysical and engineering interpretation, and stimulation techniques. Integrated geologic studies of the three priority basins containing tight sands and selected by DOE as research targets have also been pursued as part of this new effort. To date, the following tentative conclusions have evolved: Permeability of the tight gas sands can be as much as three to four orders of magnitude lower than conventional gas deposits. Nineteen western geologic basins and trends containing significant amounts of tight gas have been identified. Gas resources in the priority geologic basins are Piceance Basin, 49 tcf., Uinta Basin, 20 tcf., and Greater Green River Basin, 136 tcf. The presence of natural micro-fractures within the production zone of a reservoir and the effective propped length of hydraulically-induced fractures are the critical parameters for successful development of tight sand resources. 8 figures.

  20. Changed trends of major causes of visual impairment in Sichuan, China from 1987 to 2006

    PubMed Central

    Chen, Hui; Fan, Ying-Chuan; He, Qi-Hong; Wu, Xiao-Yun; Wei, Min; Eichner, June E.; Farris, Bradley K.; Hildebrand, P. Lloyd; Lei, Chun-Tao; Wu, Shu-Hua; Yang, Jing-Yun

    2014-01-01

    AIM To study the trends of major causes of visual impairment (VI) in adults in Sichuan, China and evaluate the effect of aging on the trends. METHODS We used data from the National Sample Survey on Disabilities (NSSD) in Sichuan province conducted in 1987 and 2006. The age-adjusted prevalence of major causes of VI and the prevalence stratified by age in each cause were calculated and compared. The association between age and each cause of VI was also analyzed. RESULTS Retinal disease increased and became the second leading cause of VI in 2006 while blinding trachoma decreased markedly. Cataract and non-trachomatous corneal diseases were among the leading causes of VI in both years. We found associations between age and causes of VI, with age showing the strongest association with cataract and relatively lower associations with other causes. CONCLUSION In the last two decades, dramatic changes occurred in the major causes of VI with significantly increased retinal disease and decreased blinding trachoma. Aging of the population might be an important factor accounting for the changed trends of VI. Understanding the prevalence of VI, its major causes and trends over time can assist in prioritizing and developing effective interventional strategies and monitoring their impact. PMID:24634880

  1. Factors associated with drinking alcohol before visiting female sex workers among men in Sichuan Province, China.

    PubMed

    Yang, Cui; Latkin, Carl; Luan, Rongsheng; Nelson, Kenrad

    2013-02-01

    Alcohol use in commercial sex is highly prevalent globally and alcohol use in conjunction with sexual activity might increase the probability of risky behaviors. In the current study, we explored individual and contextual factors associated with drinking alcohol before visiting female sex workers (FSWs) among 560 male clients in Sichuan province, China. A cross-sectional survey was conducted in Sichuan province, China. Over one-fifth (21.1 %) of the participants reported always using alcohol before having sex with FSWs. As compared to those who reported not always drinking alcohol before having sex with FSWs, male clients who reported always drinking alcohol before having sex with FSWs had higher income, were more likely to have main sex partners, to drink alcohol daily, to report minor depressive symptoms and were more likely to visit FSWs with friends rather than by themselves. Results from this study highlight the importance of addressing alcohol use among men who pay for sex in China. Future interventions should promote alcohol-related norms in reducing the harms associated with consuming alcohol. PMID:22806054

  2. Weaning practices and growth in rural Sichuan infants: a positive deviance study.

    PubMed

    Guldan, G S; Zhang, M Y; Zhang, Y P; Hong, J R; Zhang, H X; Fu, S Y; Fu, N S

    1993-06-01

    To understand some of the factors involved in weaning and growth faltering in rural China, a cross-sectional positive deviance study was undertaken among 389 rural 4-12-month-old infants from two townships of a county in Sichuan. The infants' mothers were interviewed about their child-feeding practices and other sociodemographic information, and anthropometric measurements were made on their infants. Positive deviant infants (those growing adequately in environments in which the majority of the children suffer from growth retardation and malnutrition) were identified from the Chinese WAZ-scores calculated from the anthropometric measurements. Feeding practices found to be associated with the better growth of the positive deviant infants included breastfeeding through age 12 months, feeding soybean milk, liver and pork blood products on a more than weekly basis during the ages of 7-9 months, not feeding rice flour (mifen) before age 7 months, and not giving supplements or tonics. Mothers' nutrition knowledge was also associated with positive deviance status. The relevance of the findings is discussed with respect to designing nutrition education interventions for rural Sichuan. PMID:8326537

  3. Distribution of the Crustal Magnetic Field in Sichuan-Yunnan Region, Southwest China

    PubMed Central

    Bai, Chunhua; Kang, Guofa; Gao, Guoming

    2014-01-01

    Based on the new and higher degree geomagnetic model NGDC-720-V3, we have investigated the spatial distribution, the altitude decay characteristics of the crustal magnetic anomaly, the contributions from different wavelength bands to the anomaly, and the relationship among the anomaly, the geological structure, and the geophysical field in Sichuan-Yunnan region of China. It is noted that the most outstanding feature in this area is the strong positive magnetic anomaly in Sichuan Basin, a geologically stable block. Contrasting with this feature, a strong negative anomaly can be seen nearby in Longmen Mountain block, an active block. This contradiction implies a possible relationship between the magnetic field and the geological activity. Completely different feature in magnetic field distribution is seen in the central Yunnan block, another active region, where positive and negative anomalies distribute alternatively, showing a complex magnetic anomaly map. Some fault belts, such as the Longmen Mountain fault, Lijiang-Xiaojinhe fault, and the Red River fault, are the transitional zones of strong and weak or negative and positive anomalies. The corresponding relationship between the magnetic anomaly and the geophysical fields was confirmed. PMID:25243232

  4. Relationship Between Heat Flows and Geological Structures in the Sichuan Basin, P.R. China

    SciTech Connect

    Zeng, Y.; Yu, H.; Wang, X.

    1995-01-01

    Based on an extensive data collection and analysis, this research has provided reliable representations of the features of the geothermal fields, their heat flow, and relationships with geological structures in the Sichuan Basin. The isotherms below a depth of 1,000 m show high values in the Central Uplift and the Southwest Uplift, and low values in the Northwest and Southeast Depressions. These features probably indicate undulation of crystalline basement and structural depression. At depths greater than 3,000 m, the isotherms tend to become simpler and regionalized. The mean heat flow in the basin is 69.1 mW/m{sup 2}. In the Central Uplift, the Northwest Depression and the East of the basin, heat-flow values range from 58.6 to 71.2 mW/m{sup 2}, with a mean value of 66.1 mWE/m{sup 2}. In the south and southwest, it varies from 76.6 to 100.5 mW/m{sup 2}, with a mean value of 86.2 mW/m{sup 2}. High heat-flow values occur within the uplift of the crystalline basement in the southwest Sichuan, and the heat flow decreases from the south, through the central area, to the northwest.

  5. Acid Deposition

    EPA Science Inventory

    This indicator presents acid deposition trends in the contiguous U.S. from 1989 to 2007. Data are broken down by wet and dry deposition and deposition of nitrogen and sulfur compounds. Acid deposition is particularly damaging to lakes, streams, and forests and the plants and a...

  6. Active fold-thrust belts in the foreland of eastern Tibet, the Longquan and Xiongpu anticlines in Sichuan, China

    NASA Astrophysics Data System (ADS)

    Lee, Jian-Cheng; Chan, Yu-Chang; Lu, Chia-Yu; Chen, Chih-Tung; Chu, Hao-Tsu; Liu, Yuiping; Li, Jianzhong

    2016-04-01

    The 2008 M7.9 Wenchuan earthquake ruptured from the Longmenshan fault system, which is the frontal thrust system in eastern Tibet. Further east toward the foreland area in the Sichuan basin, it sits two anticlinal structures, the Longquan and Xiongpu anticlines, which trends sub-parallel to the Longmenshan range with a distance of about 70-100 km to the mountain front. It is widely considered that these two anticlinal features are attributed to propagation of the eastward extrusion of the eastern Tibetan plateau, similar to the stress system the Wenchuan earthquake. In this study, we carried out field investigations on these two active anticlinal structures in order to characterize the bulk deformation of the anticlines. We also conducted fracture analysis and fault-slip data analysis, in an attempt to characterize the fracture developments of the rock and the paleostress states related to the faulting events associated growth of the anticlines. We thus constructed a series of geological cross sections along these two anticlines. Our results show that the Longquan anticline is characterized by pop up structure with a dominant west-vergent thrust (i.e., backthrust) on the western limb. On the other hand to the eastern limb, an east-vergent thrust only well developed in the middle part of the anticline and die out toward the north and the south. For the Xiongpu anticline, it is characterized by a pre-dominant west-vergent backthrust system without developing an east-vergent thrust. A strike-slip fault and a series of N-S-trending pop-up thrusts cut across the Xiongpu anticline indicate a rather complex stress system with two dominant compression directions, NW-SE and E-W, subsequently or alternatively affected the area. Finally, the fracture analysis revealed that 2-3 pre-dominant bedding-perpendicular fracture sets are commonly developed in the massive sandstone layers. Most of them seemingly are of the characteristics of the mode I open joint, without clear

  7. The zeolite deposits of Greece

    USGS Publications Warehouse

    Stamatakis, M.G.; Hall, A.; Hein, J.R.

    1996-01-01

    Zeolites are present in altered pyroclastic rocks at many localities in Greece, and large deposits of potential economic interest are present in three areas: (1) the Evros region of the province of Thrace in the north-eastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene age and are rich in heulandite and/or clinoptilolite. Those of Kimolos and Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrological system by the action of meteoric water, and those of the western Aegean islands in a similar way but under conditions of high heat flow, whereas the deposits in Samos were formed in a saline-alkaline lake.

  8. Global deposition of airborne dioxin.

    PubMed

    Booth, Shawn; Hui, Joe; Alojado, Zoraida; Lam, Vicky; Cheung, William; Zeller, Dirk; Steyn, Douw; Pauly, Daniel

    2013-10-15

    We present a global dioxin model that simulates one year of atmospheric emissions, transport processes, and depositions to the earth's terrestrial and marine habitats. We map starting emission levels for each land area, and we also map the resulting deposits to terrestrial and marine environments. This model confirms that 'hot spots' of deposition are likely to be in northern Europe, eastern North America, and in parts of Asia with the highest marine dioxin depositions being the northeast and northwest Atlantic, western Pacific, northern Indian Ocean and the Mediterranean. It also reveals that approximately 40% of airborne dioxin emissions are deposited to marine environments and that many countries in Africa receive more dioxin than they produce, which results in these countries being disproportionately impacted. Since human exposure to dioxin is largely through diet, this work highlights food producing areas that receive higher atmospheric deposits of dioxin than others. PMID:23962732

  9. [How to launch the activity of propaganda month of family planning in Sichuan province].

    PubMed

    Wan, C; Tan, S S

    1983-01-29

    In mid-July to the end of August 1982, the Sichuan Provincial Party Committee and the Sichuan Provincial People's Government launched a 1-time family planning propaganda month in all of its cities and villages. The purpose was to promote and to carry out consistently and thoroughly the "Going a Step Further in Family Planning Work Directive" of the Central Committee of the Chinese Communist Party and the State Council. Through the propaganda efforts, cadres and masses of Sichuan became familiar with the Party's family planning policy and the basis for population theory, thereby benefitting the nation, its people and future generations. In addition, people sensed the urgency, glory, and responsibility of population control. Based on incomplete data, during the month of propaganda, there were 174,182 new applications for 1 Child Certificates, which was 94.82% of the certificates applied for in the 1st half of 1982; 419,696 cases of contraceptive use, or 43.32% of those using them in the 1st 6 months of the year; 247,808 cases of those taking remedial measures, or 35.62% of those doing so in the 1st half of the year. The 1 child rate rose from a June 1982 figure of 68.21% to 68.71%; the multiple child rate dropped from 8.24% to 8%. The projected birthrate for 1982 is 16-17/1000. The success of the propaganda month was attained through: 1) organized responsibility, clearly defined goals and complete preparations that existed at all provincial Party and provincial Governmental levels; 2) the propaganda effort that was a priority of all governmental leaders, who utilized every propaganda tool available; At every level, propaganda sessions of every kind were convened, the entire propaganda machine was mobilized, and propaganda was brought into the home and to individuals; 3) propaganda, experience, and implementation that were all utilized simultaneously; and 4) the organization and administration of propaganda work that was systematized. PMID:12312939

  10. Retrieval and spatial-temporal analysis of aerosol in Sichuan province based on multi-source remote sensing

    NASA Astrophysics Data System (ADS)

    Liu, Zhihong; Liu, Hu; Zhang, Yang; Ge, Ying

    2015-04-01

    Sichuan Basin is one of the serious haze regions in China. It has great significance to monitor the atmospheric haze in Sichuan Basin. In this study, MOD04 product , OMI-NO2 product and OMI-SO2 product were used to analysis the spatial and temporal distribution characteristic of atmospheric pollutants in Sichuan from year 2008 to 2012. Micro pulse lidar (MPL) and HJ-1 satellites were used to retrieve the aerosol extinction coefficient and aerosol optical depth (AOD). Also we established a linear relationship between the AOD and PM10. The MOD04 data showed that the AOD in west Sichuan plateau was relatively low. The annual AOD-average in the regions such as Kangding, Maerkang, Xichang and Yaan was about 0.2. The Sichuan Basin such as Chengdu, Deyang, Mianyang has relatively higher annual AOD-average which was about 0.8 to 1.0, and it had obvious seasonal change feature. The spatial and temporal distribution of aerosol optical depth in Chendu showed obvious urban characteristics. These characteristics are related to the industrial situation, the location and the climate condition of Sichuan. Year 2011 has this highest annual AOD-average value. The OMI-NO2 product showed that the distribution characteristic of NO2 in Sichuan was similar with aerosol. The NO2 concentration was about 0.7 molec/cm2 in west Sichuan plateau and greater than 4.2 molec/cm2 in Chengdu, Deyang, Mianyang. However, the SO2 distribution characteristic was slightly different. The SO2 concentration was low in west Sichuan plateau with an annual average concentration of 0.2 DU. Zigong, Yibin, Luzhou were the main high value areas with an annual average concentration of 1.1 DU. Fernald method was used to retrieve the aerosol extinction coefficient based on the MPL. The result showed that the daily maximum was appeared about 07:00 am and the highest aerosol extinction coefficient season was winter. The aerosol extinction coefficient was higher below the altitude of 300 m. Based on the data of HJ-1

  11. Re-emerging schistosomiasis in hilly and mountainous areas of Sichuan, China.

    PubMed Central

    Liang, Song; Yang, Changhong; Zhong, Bo; Qiu, Dongchuan

    2006-01-01

    Despite great strides in schistosomiasis control over the past several decades in Sichuan Province, China the disease has re-emerged in areas where it was previously controlled. We reviewed historical records and found that schistosomiasis had re-emerged in eight counties by the end of 2004 - seven of 21 counties with transmission control and one of 25 with transmission interruption as reported in 2001 were confirmed to have local disease transmission. The average "return time" (from control to re-emergence) was about eight years. The onset of re-emergence was commonly signalled by the occurrence of acute infections. Our survey results suggest that environmental and sociopolitical factors play an important role in re-emergence. The main challenge would be to consolidate and maintain effective control in the longer term until "real" eradication is achieved. This would be possible only by the formulation of a sustainable surveillance and control system. PMID:16501732

  12. A data-based model to locate mass movements triggered by seismic events in Sichuan, China.

    PubMed

    de Souza, Fabio Teodoro

    2014-01-01

    Earthquakes affect the entire world and have catastrophic consequences. On May 12, 2008, an earthquake of magnitude 7.9 on the Richter scale occurred in the Wenchuan area of Sichuan province in China. This event, together with subsequent aftershocks, caused many avalanches, landslides, debris flows, collapses, and quake lakes and induced numerous unstable slopes. This work proposes a methodology that uses a data mining approach and geographic information systems to predict these mass movements based on their association with the main and aftershock epicenters, geologic faults, riverbeds, and topography. A dataset comprising 3,883 mass movements is analyzed, and some models to predict the location of these mass movements are developed. These predictive models could be used by the Chinese authorities as an important tool for identifying risk areas and rescuing survivors during similar events in the future. PMID:24085622

  13. Female victimization and intimate partner violence after the May 12, 2008, Sichuan earthquake.

    PubMed

    Chan, Ko Ling; Zhang, Yulian

    2011-01-01

    This study investigates the impact of the earthquake that occurred on May 12, 2008 in Sichuan, China on stressed families already experiencing domestic violence. We hypothesized that cumulative postdisaster stress would increase marital aggression and that the well-being of victims would deteriorate following the quake. A total of 186 women were recruited for this study. Results show that all types of family violence, including psychological aggression and physical violence between partners, increased after the earthquake. We provided preliminary evidence that psychological aggression was significantly associated with the detrimental effects on victims' mental and physical functioning. The findings support the need for violence assessment among victims of earthquakes, and we recommend that violence prevention be considered as part of the intervention during such natural disasters. PMID:21846023

  14. A qualitative study on commercial sex behaviors among male clients in Sichuan Province, China

    PubMed Central

    Yang, Cui; Latkin, Carl A.; Liu, Peng; Nelson, Kenrad E.; Wang, Cunlin; Luan, Rongsheng

    2015-01-01

    Males who seek commercial sex have been identified as an important “bridging population” in the transmission of HIV. There is little information on the HIV-related risk perceptions and behaviors among commercial sex male clients (CSMCs) in China. This study reports qualitative findings from six focus groups and 41 in-depth interviews with CSMCs in Sichuan Province, China. Commercial sex visits were described as a group activity and associated with patterns of social-network specific interactions and norms. Primary motivations for visiting female sex workers included peer pressure, stress reduction, and fulfilling a need for an intimate and emotional support. Male clients’ decisions about condom use were influenced by their perceived norms of condom use, susceptibility of HIV infection, and the condom policy and availability in the establishments. Implications of these findings for further research and interventions are discussed. PMID:20390503

  15. The loss of genetic diversity in Sichuan taimen as revealed by DNA fingerprinting.

    PubMed

    Wu, Xue-Chang

    2006-06-01

    Species endangerment often derives from the "endangerment" of genetic diversity, thus loss of genetic diversity is an important cause of species extinction. Since historical specimens were unavailable, previous studies mainly described the genetic diversity status in the current population rather than the loss of genetic variation over time. In this study, we collected samples during 1998-1999 and obtained historical specimens from 1957 to 1958. Based on the two sets of fish, we determined the changes in genetic diversity of Sichuan taimen using DNA fingerprinting. The differences in genetic parameters between the present samples and historical taimens revealed their loss of genetic variation. As a result, the existing populations have lower viability, and proper management has to be implemented to preserve genetic diversity. PMID:16944294

  16. Diversity and phylogeny of rhizobia associated with Desmodium spp. in Panxi, Sichuan, China.

    PubMed

    Xu, Kai Wei; Zou, Lan; Penttinen, Petri; Zeng, Xiangzhong; Liu, Ming; Zhao, Ke; Chen, Cuiping; Chen, Yuan Xue; Zhang, Xiaoping

    2016-02-01

    Thirty-four rhizobial isolates were obtained from root nodules of four wild Desmodium species growing in Panxi, Sichuan, China. According to the combined ARDRA and IGS-RFLP (CACAI) cluster analysis, Rhizobium, Pararhizobium and Mesorhizobium isolates outnumbered Bradyrhizobium isolates. In general, the isolates representing the same species from the same site clustered together. Furthermore, the four Desmodium species were all nodulated by more than one rhizobial species. AFLP and phenotypic analyses showed that the 34 isolates represented at least 32 distinct strains. None of the strains were found from more than one site or host, indicating a high degree of rhizobial diversity in Panxi. In the multilocus sequence analysis, the isolates were assigned to Pararhizobium giardinii, Bradyrhizobium japonicum, Mesorhizobium septentrionale, and to undescribed species of the genera Rhizobium, Bradyrhizobium and Agrobacterium. PMID:26654528

  17. The public health system response to the 2008 Sichuan province earthquake: a literature review and interviews.

    PubMed

    Lin, Leesa; Ashkenazi, Isaac; Dorn, Barry C; Savoia, Elena

    2014-10-01

    This paper describes and analyses the public health system response to the deadly earthquake in Sichuan province, China, in May 2008. Drawing on an experiential learning project consisting of a literature review and field research, including a series of interviews with medical and public health professionals, policy-makers and first responders, a conceptual framework was developed to describe the response. This approach emphasises the pre-existing preparedness level of the medical and public health systems, as well as social, economic and geo-political factors that had an impact on mitigation efforts. This framework was used to conduct post-disaster analyses addressing major response issues and examining methods employed during the public health response to the disaster. This framework could be used to describe and analyse the emergency response to other disasters. PMID:25196335

  18. Posttraumatic stress disorder symptoms among adult survivors of the 2008 Sichuan earthquake in China.

    PubMed

    Chan, Cecilia Lai Wan; Wang, Chong-Wen; Qu, Zhiyong; Lu, Ben Qibin; Ran, Mao-Sheng; Ho, Andy Hau Yan; Yuan, Yin; Zhang, Braven Qiang; Wang, Xiying; Zhang, Xiulan

    2011-06-01

    This study examined the estimated prevalence rate of posttraumatic stress disorder (PTSD) symptoms and associated risk factors among Chinese adult survivors 7 to 8 months after the 2008 Sichuan earthquake. The sample was recruited from 2 areas close to the epicenter but of different distances. The estimated rate of PTSD symptoms was 55.6% and 26.4% respectively in the two areas. Loss of a child was a strong predictive factor for PTSD symptoms for the parents. Other predictive factors included female gender, loss of a parent, loss of friends or neighbors, residential house damage or collapse, and proximity to the epicenter. Effective and sustainable mental health services are needed and should be directed particularly to bereaved survivors. PMID:21608035

  19. [Survey of suicidal mortality rate in several districts of Sichuan province].

    PubMed

    Hu, Z; Liu, X; Huo, K; Zhang, W

    1992-09-01

    A survey of the suicidal mortality rates in two cities and six districts in Sichuan province was carried out from 1980 to 1988 by the authors. The average suicidal mortality rate (ASMR) in these districts from 1980 to 1988 was 15.5/10(5), and the population and suicidal mortality rate positively correlated, r = 0.53. The ASMR in the male was 14.9/10(5), in the female 17.1/10(5), in the urban area 9.4/10(5), in the rural area 21/10(5), and the ASMR in the urban area was higher than that in the rural area (P < 0.05). The peak age of suicidal mortality was around twenty years. PMID:1304550

  20. Molecular investigation of Torque teno sus virus in geographically distinct porcine breeding herds of Sichuan, China

    PubMed Central

    2013-01-01

    Background Torque teno sus virus (TTSuV), infecting domestic swine and wild boar, is a non-enveloped virus with a circular, single-stranded DNA genome. which has been classified into the genera Iotatorquevirus (TTSuV1) and Kappatorquevirus (TTSuV2) of the family Anelloviridae. A molecular study was conducted to detect evidence of a phylogenic relationship between these two porcine TTSuV genogroups from the sera of 244 infected pigs located in 21 subordinate prefectures and/or cities of Sichuan. Results Both genogroups of TTSuV were detected in pig sera collected from all 21 regions examined. Of the 244 samples, virus from either genogroup was detected in 203 (83.2%), while 44 animals (18.0%) were co-infected with viruses of both genogroups. Moreover, TTSuV2 (186/244, 76.2%) was more prevalent than TTSuV1 (61/244, 25%). There was statistically significant difference between the prevalence of genogroups 1 infection alone (9.4%, 23/244) and 2 alone (64.8%, 158/244), and between the prevalence of genogroups 2 (76.2%, 186/244) and both genogroups co-infection (18.0%, 44/244). The untranslated region of the swine TTSuV genome was found to be an adequate molecular marker of the virus for detection and surveillance. Phylogenetic analysis indicated that both genogroups 1 and 2 could be further divided into two subtypes, subtype a and b. TTSuV1 subtype b and the two TTSuV2 subtypes are more prevalent in Sichuan Province. Conclusions Our study presents detailed geographical evidence of TTSuV infection in China. PMID:23705989

  1. Onsite infectious agents and toxins monitoring in 12 May Sichuan earthquake affected areas.

    PubMed

    Yao, Maosheng; Zhu, Tong; Li, Kejun; Dong, Shuofei; Wu, Yan; Qiu, Xinghua; Jiang, Bo; Chen, Liansheng; Zhen, Shiqi

    2009-11-01

    At 14:28 on 12 May 2008, Sichuan Province of China suffered a devastating earthquake measuring 8.0 on the Richter scale with more than 80 000 human lives lost and millions displaced. With inadequate shelter, poor access to health services, and disrupted ecology, the survivors were at enormous risk of infectious disease outbreaks. This work, believed to be unprecedented, was carried out to contain a possible outbreak through onsite monitoring of airborne biological agents in the high-risk areas. In such a mission, a mobile laboratory was developed using a customized vehicle along with state-of-art bioaerosol and molecular equipment and tools, and deployed to Sichuan 11 days after the earthquake. Using a high volume bioaerosol sampler (RCS High Flow) and Button Inhalable Aerosol Sampler equipped with gelatin filters, a total of 55 air samples, among which are 28 filter samples, were collected from rubble, medical centers, and camps of refugees, troops and rescue workers between 23 May and 9 June, 2008. After pre-treatment of the air samples, quantitative polymerase chain reaction (qPCR), gel electrophoresis, limulus amebocyte lysate (LAL) assay and enzyme-linked immunosorbent assay (ELISA) were applied to detect infectious agents and to quantify environmental toxins and allergens. The results revealed that, while high levels of endotoxin (180 approximately 975 ng/m3) and (1,3)-beta-d-glucans (11 approximately 100 ng/m3) were observed, infectious agents such as Bacillus anthracis, Bordetella pertussis, Neisseria meningitidis, Mycobacterium tuberculosis, influenza A virus, bird flu virus (H5N1), enteric viruses, and Meningococcal meningitis were found below their detection limits. The total bacterial concentrations were found to range from 250 to 2.5 x 10(5) DNA copies/L. Aspergillus fumigatus (Asp f 1) and dust mite allergens (Der p 1 and Der f 1) were also found below their detection limits. PMID:19890556

  2. Thickness of western mare basalts

    NASA Technical Reports Server (NTRS)

    Dehon, R. A.

    1979-01-01

    An isopach map of the basalt thickness in the western mare basins is constructed from measurements of the exposed external rim height of partially buried craters. The data, although numerically sparse, is sufficiently distributed to yield gross thickness variations. The average basalt thickness in Oceanus Procellarum and adjacent regions is 400 m with local lenses in excess of 1500 m in the circular maria. The total volume of basalt in the western maria is estimated to be in the range of 1.5 x 10 to the 6th power cu km. The chief distinction between the eastern and western maria appears to be one of basalt volumes erupted to the surface. Maximum volumes of basalt are deposited west of the central highlands and flood subjacent terrain to a greater extent than on the east. The surface structures of the western maria reflect the probability of a greater degree of isostatic response to a larger surface loading by the greater accumulation of mare basalt.

  3. EVIDENCE OF AIRBORNE CONTAMINATION OF WESTERN NORTH AMERICAN MOUNTAIN ECOSYSTEMS

    EPA Science Inventory

    There is emerging evidence that mountain ecosystems in the western USA are receiving deposition of persistent bioaccumulative toxicants with origins in North America and elsewhere in the Northern Hemisphere. The toxic materials include metals and organic compounds. Of particula...

  4. Population Genetic Structure and the Migration of Puccinia striiformis f. sp. tritici Between the Gansu and Sichuan Basin Populations of China.

    PubMed

    Liang, Junmin; Liu, Xiufeng; Li, Yong; Wan, Qiong; Ma, Zhanhong; Luo, Yong

    2016-02-01

    Puccinia striiformis f. sp. tritici is the causal pathogen of interregional epidemics of wheat stripe rust in China via long-distance migration. Gansu Province serves as putative inoculum center providing oversummering inoculum, while Sichuan Basin area serves as a region providing huge amounts of overwintering inoculum. Thus, the relationship between these two regions in population exchange and migration become important in prediction of interregional epidemics. In this study, we compared the population genetic structure and race composition between Gansu and Sichuan Basin populations to infer their migration relationships. A total of 526 isolates, spanning 3 years, were genotyped using eight pairs of amplified fragment length polymorphism markers, and a subset of 98 isolates were inoculated onto 19 Chinese differentials to perform the race analysis. Twenty-three common races and 26 shared genotypes supplied molecular evidence for migration between Gansu and Sichuan Basin populations. Bayesian assignment and principal component analysis revealed that the genetic group assignment of the Sichuan Basin populations (10SB and 11SB) changed in the spring to align with the fall Gansu populations in the prior seasons (09GS and 10GS), which indicated an asymmetric migration from Gansu Province to the Sichuan Basin area. The linkage disequilibrium and the parsimony tree length permutation test revealed a strong annual recombination signal in the Gansu populations and an inconsistent signal in the Sichuan Basin populations. PMID:26506459

  5. Review of lignite resources of western Tennessee and the Jackson Purchase area, western Kentucky

    USGS Publications Warehouse

    Hackley, Paul C.; Warwick, Peter D.; Thomas, Roger E.; Nichols, Douglas J.

    2006-01-01

    Introduction: This review of the lignite deposits of western Tennessee and the Jackson Purchase area in western Kentucky (Fig. 1) is a preliminary report on part of the U.S. Geological Survey's National Coal Resource Assessment of the Gulf Coastal Plain Coal Province. Lignite deposits of western Kentucky and Tennessee are an extension of the Gulf Coastal Plain Coal Province (Cushing and others, 1964), and currently are not economic to mine. These deposits have not been extensively investigated or developed as an energy resource. This review includes a description of the geology of the lignite-bearing units, a discussion of the available coal quality data, and information on organic petrology. Palynological data for lignite samples collected in Kentucky and Tennessee as part of this work are presented in an Appendix.

  6. The diatom genus Actinocyclus in the Western United States

    USGS Publications Warehouse

    Bradbury, J. Platt, (Edited By); Krebs, William N.

    1995-01-01

    Ten new and four known taxa of the diatom genus Actinocyclus are described, illustrated, and (or) noted from middle Miocene lake deposits in the Western United States. A key is presented to help separate the taxa based on morphological criteria visible in the light microscope. The geologic ranges of Actinocyclus species in the Western United States are discussed based on examination of over 100 localities of diatomaceous lacustrine deposits.

  7. Geochronology of cave deposits at Liang Bua and of adjacent river terraces in the Wae Racang valley, western Flores, Indonesia: a synthesis of age estimates for the type locality of Homo floresiensis.

    PubMed

    Roberts, R G; Westaway, K E; Zhao, J-x; Turney, C S M; Bird, M I; Rink, W J; Fifield, L K

    2009-11-01

    A robust timeframe for the extant cave deposits at Liang Bua, and for the river terraces in the adjoining Wae Racang valley, is essential to constrain the period of existence and time of extinction of Homo floresiensis and other biota that have been excavated at this hominin type locality. Reliable age control is also required for the variety of artifacts excavated from these deposits, and to assist in environmental reconstructions for this river valley and for the region more broadly. In this paper, we summarize the available geochronological information for Liang Bua and its immediate environs, obtained using seven numerical-age methods: radiocarbon, thermoluminescence, optically- and infrared-stimulated luminescence (collectively known as optical dating), uranium-series, electron spin resonance, and coupled electron spin resonance/uranium-series. We synthesize the large number of numerical age determinations reported previously and present additional age estimates germane to questions of hominin evolution and extinction. PMID:19254806

  8. Chronic health needs immediately after natural disasters in middle-income countries: the case of the 2008 Sichuan, China earthquake.

    PubMed

    Chan, Emily Y Y; Kim, Jackie

    2011-04-01

    Few studies have focused on chronic health needs immediately after natural disasters in middle-income countries. This study examines chronic medical needs during the acute phase after the 2008 Sichuan earthquake. A descriptive, cross-sectional study was conducted in an emergency triage clinic in Sichuan, China. Information on physical, social, and public health preparedness was collected in predesigned templates. Descriptive and Pearson's χ association analyses were conducted. One hundred and eighty-two evacuees were received at the triage site. Of these, 54% required trauma treatment and 77% of evacuated patients who required care had underlying chronic medical conditions. Tetanus immunizations and the possession of chronic health medication were low, particularly among older patients. Chronic health needs constituted a significant proportion of emergency care during the acute phase in the study population. Effective post-disaster assistance requires attention to demographic and epidemiological population profiles. PMID:20679898

  9. Phylogenetic analysis reveals that Japanese encephalitis virus genotype III is still prevalent in swine herds in Sichuan province in China.

    PubMed

    Wu, Rui; Wang, Qiao; Liu, Hongming; Chai, Chunxia; He, Bo; Huang, Xiaobo; Wen, Yiping; Wen, Xintian; Yan, Qiguai; Ma, Xiaoping; Cao, Sanjie

    2016-06-01

    The genome of JEV strain SC201301, which was isolated from an aborted fetal piglet in 2013 in Sichuan province in China, was completely sequenced and phylogenetically analyzed. Sequence alignments showed that the SC201301 strain shared 97-100% sequence identity with other genotype III strains but showed less similarity to genotype I representative JEVs. Phylogenetic analysis indicated that the SC201301 strain belonged to genotype III and was most closely related to representative strains such as SA14-14-2, HW and SH0601. Our findings suggest that JEV genotype III is still prevalent in swine herds in Sichuan province in China, and thus, there is an urgent need to monitor the infection status of JEV among swine herds in China. PMID:26976139

  10. Metal Distribution and Contamination Assessment in Drainage Ditch Water in the Main Rice/Vegetable Area of Sichuan Hilly Basin.

    PubMed

    Kumwimba, Mathieu Nsenga; Zhu, Bo; Wang, Tao; Yuan, Zhao; Muyembe, Diana Kavidia

    2016-02-01

    In order to assess the impact of four land use changes on metal concentrations in the hilly Sichuan Basin of China, 71 surface water samples were collected in July and November 2014. Samples from residential ditch water were found to have higher metal concentrations than those in other types of ditches, while the lowest occurred in barren land ditch water. However, the selected metals were below the Chinese surface water quality standards and WHO (2011). The pollution index of four determined land use types was also below the critical pollution index, suggesting there were low levels of pollution in Sichuan Basin. Arsenic was the most important pollutant of concern. Results indicate steps should be taken to control and reduce the risk of metals released from residential ditch water. PMID:26662271

  11. Simulated seasonal variations in wet acid depositions over East Asia.

    PubMed

    Ge, Cui; Zhang, Meigen; Zhu, Lingyun; Han, Xiao; Wang, Jun

    2011-11-01

    The air quality modeling system Regional Atmospheric Modeling System-Community Multi-scale Air Quality (RAMS-CMAQ) was applied to analyze temporospatial variations in wet acid deposition over East Asia in 2005, and model results obtained on a monthly basis were evaluated against extensive observations, including precipitation amounts at 704 stations and SO4(2-), NO3-, and NH4+ concentrations in the atmosphere and rainwater at 18 EANET (the Acid Deposition Monitoring Network in East Asia) stations. The comparison shows that the modeling system can reasonably reproduce seasonal precipitation patterns, especially the extensive area of dry conditions in northeast China and north China and the major precipitation zones. For ambient concentrations and wet depositions, the simulated results are in reasonable agreement (within a factor of 2) with observations in most cases, and the major observed features are mostly well reproduced. The analysis of modeled wet deposition distributions indicates that East Asia experiences noticeable variations in its wet deposition patterns throughout the year. In winter, southern China and the coastal areas of the Japan Sea report higher S04(2-) and NO3- wet depositions. In spring, elevated SO4(2-) and NO3-wet depositions are found in northeastern China, southern China, and around the Yangtze River. In summer, a remarkable rise in precipitation in northeastern China, the valleys of the Huaihe and Yangtze rivers, Korea, and Japan leads to a noticeable increase in SO4(2-) and NO3- wet depositions, whereas in autumn, higher SO4(2-) and NO3-wet depositions are found around Sichuan Province. Meanwhile, due to the high emission of SO2, high wet depositions of SO4(2-) are found throughout the entire year in the area surrounding Sichuan Province. There is a tendency toward decreasing NO3- concentrations in rainwater from China through Korea to Japan in both observed and simulated results, which is a consequence of the influence of the continental

  12. The structure and sedimentary sequence of intracratonic rift from Late Sinian to Early Cambrian in the Sichuan Basin, South China

    NASA Astrophysics Data System (ADS)

    Gu, Zhidong; Zhang, Baomin; Lu, Weihu; Zhai, Xiufen; Jiang, Hua

    2016-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze craton of South China, and there is developed an intracratonic rift from Late Sinian to Early Cambrian in the middle of Sichuan Basin, and the paper systematically discusses the structure and sedimentary sequence of the intracratonic rift based on the fields, drilling and seismic data, and so on. Detailed structural interpretation of 2D and 3D seismic profiles displays the development of two stages of intracratonic rift due to regional extension with the depth of 2000m, and plane distribution of intracratonic rift presents the V-pattern from the northwest to the southeast in the middle of Sichuan Basin with the width from 100km to 20km. The drilling data from the intracratonic rift shows the obvious thinning of Upper Sinian and thickening of Lower Cambrian. And field outcrops situated in the intracratonic rift reveal that the Upper Sinian is mainly composed of siliceous rock, shale and carbonate, with the thickness of less than 100m, but the thickness of Upper Sinian on the platform reaches 1000m by contrast; They also reveals that Lower Cambrian is mainly composed of shale, mudstone, and siltstone with the development of gravity current, and the thickness of Lower Cambrian reaches 2000m. The formation of intracratonic rift may be initiated by pre-existing basement weakness zone and deep mantle dynamics.

  13. Study on suitable distribution areas of Notopterygium incisum in Sichuan province based on remote sensing and GIS.

    PubMed

    Shang, Xue; Dong, Li-jun; Wen, Lu-jun; Peng, Wen-fu; Xu, Xin-liang; Fang, Qing-mao

    2015-07-01

    Notopterygium incisum is the important medicinal materials of the Tibetan-Qiang medical system in China, also one of the rare and endangered medicinal materials in the Plateau areas in the meantime. Taking the planting of in Sichuan province as an example, research on the N. incisum in Sichuan utilize remote sensing and GIS techniques, bind growth environment factor, including height factor, average annual precipitation, average annual temperature, forest information, were chosen according to habitat conditions. And combine field measurement to verify. The results indicate that N. incisum resources in Sichuan province were mainly distributed in the alpine valley and the northwest of the plateau, which suitability distribution areas of 4145 km2 approximately and accounting for 2% of the total area. Suitability areas accounting for more than 2% of the respective total area in Heishui county, Lixian county, Xiaojin county, Kangding county, ect. According to the field investigation and the related document information record, drawn that the suitability distribution based on RS and GIS were corresponded with the actual distribution areas of N. incisum resources. It's feasible to divide the suitability distribution area of N. incisum using RS and GIS, which will provide a scientific basis for a comprehensive investigation of the distribution as well as its rational exploitation and protection. PMID:26697677

  14. Present-day kinematics of the eastern Tibetan Plateau and Sichuan Basin: Implications for lower crustal rheology

    NASA Astrophysics Data System (ADS)

    Rui, X.; Stamps, D. S.

    2016-05-01

    The Sichuan Province comprises the cratonic Sichuan Basin and the eastern Tibetan Plateau separated by the recently activated Longmen Shan fault zone, thus providing a natural laboratory to study interseismic and postseismic processes. In this work we compute a new regional geodetic velocity solution from most of the continuous Global Navigation Satellite Systems (GNSS)/GPS data available in the Sichuan Province that we assess for transient postseismic deformation. For 11 continuous sites in close proximity to the Wenchuan 2008 event epicenter that were operational during the Wenchuan event we find an average short-term relaxation time of 11 days with maximum amplitude of 6.6 mm for the postseismic transient and no resolvable long-term transient. Using tests for block rigidity guided by previous kinematic studies we elucidate a longer-term transient in GNSS/GPS observations collected after the Wenchuan event that spans an extensive region of the eastern Tibetan Plateau. We correct for transients, produce an updated secular velocity field, and revise the kinematics of the region using elastic block modeling. Our results indicate that predicted slip rates are in good agreement with both geological and GNSS/GPS velocity profile-derived results, and we resolve two independent blocks with the expanded GNSS/GPS data set. Our constraints on the spatial extent of long-term postseismic deformation support models of ductile lower crust in the eastern margin of the Tibetan Plateau.

  15. Identification of differentially expressed genes between hepatocytes of Landes geese (Anser anser) and Sichuan White geese (Anser cygnoides).

    PubMed

    Pan, Zhixiong; Wang, Jiwen; Han, Chunchun; Zhai, Ningfeng; Lv, Jia; Zhou, Zehui; Tang, Hui; Xiang, Shuxia; Wang, Jing; Li, Liang

    2010-12-01

    In this study, we examined gene expression in order to identify genes that are differentially expressed between the hepatocytes of Sichuan White geese and Landes geese. We hypothesized that such genes may be involved in the different predispositions between these two species to develop hepatic steatosis. RNA was isolated from primary hepatocytes of the two species, and suppression subtractive hybridization was employed to screen for genes that showed differences in mRNA expression. We built and characterized two reciprocal cDNA libraries that were enriched in genes up-regulated in Landes geese or Sichuan White geese. Using dot blot analysis we identified 128 of 600 randomly selected sequences that demonstrated differential expression between the two species. Of these differentially expressed genes, 115 sequences shared high homology with 46 known genes and 13 sequences corresponded to eight novel expressed sequence tags (ESTs). Based on functional clustering, up and down-regulated genes were mostly related to lipid metabolism, nuclear mRNA splicing, enzyme activity and transcription control. The expression of 18 selected clones was further studied by quantitative PCR. The data showed that eight clones similar to the genes ACSL5, CTGF, CIDEA, PPARγ, PCK, GSTS1, RPS4X, and THBS1 had significantly higher expression levels in the hepatocytes of Landes geese. In contrast, seven clones similar to the genes ADH5, YBX1, ASAH1, UCB, AOPVLDL, SCD-1, and ELOVL-6 had significantly higher expression levels in the hepatocytes of Sichuan White geese. PMID:20238173

  16. Generation of isotopically and compositionally distinct water during thermochemical sulfate reduction (TSR) in carbonate reservoirs: Triassic Feixianguan Formation, Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Jiang, Lei; Worden, Richard H.; Cai, Chunfang

    2015-09-01

    Thermochemical sulfate reduction (TSR), the reaction of petroleum with anhydrite in reservoirs resulting in the growth of calcite and the accumulation of H2S, has been documented in the Feixianguan Formation dolomite reservoir in the Sichuan Basin, China. Fluid inclusion salinity and homogenization temperature data have shown that TSR results in a decrease in salinity from a pre-TSR value of 25 wt.% down to 5 wt.% as a result of water created as a byproduct of progressive TSR. We have studied the isotopic character of the water that resulted from TSR in the Feixianguan Formation by analyzing the oxygen isotopes of TSR calcite and determining the oxygen isotopes of the water in equilibrium with the TSR calcite at the temperatures determined by aqueous fluid inclusion analysis. We have compared these TSR-waters to water that would have been in equilibrium with the bulk rock, also at the temperatures determined by aqueous fluid inclusion analysis. We have found that the TSR-waters are relatively depleted in oxygen isotopes (by up to 8‰ compared to what would be expected at equilibrium between the bulk rock and water) since this type of water was specifically derived from anhydrite. The generation of relatively large volumes of low salinity, low δ18O water associated with advanced TSR in the Feixianguan Formation has also been reported in the Permian Khuff Formation in Abu Dhabi and from sour Devonian fields in the Western Canada Basin. This suggests that TSR-derived water may be a common phenomenon, the effects of which on mesogenetic secondary porosity and reservoir quality have previously been underappreciated.

  17. Erosional and depositional contourite features at the transition between the western Scotia Sea and southern South Atlantic Ocean: links with regional water-mass circulation since the Middle Miocene

    NASA Astrophysics Data System (ADS)

    Pérez, Lara F.; Hernández-Molina, F. Javier; Esteban, Federico D.; Tassone, Alejandro; Piola, Alberto R.; Maldonado, Andrés; Preu, Benedict; Violante, Roberto A.; Lodolo, Emanuele

    2015-08-01

    The aim of the present study was to characterise the morpho-sedimentary features and main stratigraphic stacking pattern off the Tierra del Fuego continental margin, the north-western sector of the Scotia Sea abyssal plain (Yaghan Basin) and the Malvinas/Falkland depression, based on single- and multi-channel seismic profiles. Distinct contourite features were identified within the sedimentary record from the Middle Miocene onwards. Each major drift developed in a water depth range coincident with a particular water mass, contourite terraces on top of some of these drifts being associated with interfaces between water masses. Two major palaeoceanographic changes were identified. One took place in the Middle Miocene with the onset of Antarctic Intermediate Water flow and the enhancement of Circumpolar Deep Water (CDW) flow, coevally with the onset of Weddell Sea Deep Water flow in the Scotia Sea. Another palaeoceanographic change occurred on the abyssal plain of the Yaghan Basin in the Late Miocene as a consequence of the onset of Southeast Pacific Deep Water flow and its complex interaction with the lower branch of the CDW. Interestingly, these two periods of change in bottom currents are coincident with regional tectonic episodes, as well as climate and Antarctic ice sheet oscillations. The results convincingly demonstrate that the identification of contourite features on the present-day seafloor and within the sedimentary record is the key for decoding the circulation of water masses in the past. Nevertheless, further detailed studies, especially the recovery of drill cores, are necessary to establish a more robust chronology of the evolutionary stages at the transition between the western Scotia Sea and the southern South Atlantic Ocean.

  18. Quaternary Glacial Mapping in Western Wisconsin Using Soil Survey Information

    ERIC Educational Resources Information Center

    Oehlke, Betsy M.; Dolliver, Holly A. S.

    2011-01-01

    The majority of soils in the western Wisconsin have developed from glacial sediments deposited during the Quaternary Period (2.6 million years before present). In many regions, multiple advances and retreats have left a complex landscape of diverse glacial sediments and landforms. The soils that have developed on these deposits reflect the nature…

  19. Data base for the analysis of compositional characteristics of coal seams and macerals. Part 7. Petrographic variation due to depositional setting of the lower Kittanning seam, western Pennsylvania. Final report

    SciTech Connect

    Allshouse, S.D.; Davis, A.

    1984-01-01

    Detailed megascopic and microscopic petrographic analyses were conducted on samples of the Lower Kittanning seam from western Pennsylvania. Relationships were sought between the paleoenvironmental setting of the coal swamp and the vertical and lateral variability of lithotypes, maceral composition and vitrinite types. Megascopically, the four samples collected from the freshwater facies of the seam are similar in appearance and relative lithotype composition, and display no distinct vertical zonations. The sample from the marine-influenced central portion of the basin (PSOC-1340) possesses a marked vertical zonation into a bright lower zone and a dull upper zone. The lower zone is similar in appearance to the freswater samples. Detailed microscopic analyses revealed that the vertical zonation of PSOC-1340 is apparent in both the maceral and vitrinite type composition. No similar zonation is apparent in the microscopic analysis of the four freshwater facies samples. Similarities between the lower zone of PSOC-1340 and the whole seam of the freshwater samples are most apparent in the vitrinite-type analysis. The lower zone of PSOC-1340 and the whole seam from the freshwater facies are considered to be laterally equivalent coal types. The dull upper zone of PSOC-1340 is considered to have formed in response to a major change in the paleoenvironment of the swamp, probably a marine transgression. 49 references, 25 figures, 15 tables.

  20. Organic matter and sandstone-type uranium deposits: a primer

    USGS Publications Warehouse

    Leventhal, Joel S.

    1979-01-01

    Organic material is intimately associated with sandstone-type uranium deposits in the western United States.. This report gives details of the types of organic matter and their possible role in producing a uranium deposit. These steps include mobilization of uranium from igneous rocks, transportation from the surface, concentration by organic matter, reduction by organic matter, and preservation of the uranium deposit.

  1. Diversity, bioactivities, and metabolic potentials of endophytic actinomycetes isolated from traditional medicinal plants in Sichuan, China.

    PubMed

    Qiu, Peng; Feng, Zhi-Xiang; Tian, Jie-Wei; Lei, Zu-Chao; Wang, Lei; Zeng, Zhi-Gang; Chu, Yi-Wen; Tian, Yong-Qiang

    2015-12-01

    The present study was designed to determine the taxonomic diversity and metabolic activity of the actinomycetes community, including 13 traditional medicinal plants collected in Sichuan province, China, using multiple approaches such as morphological and molecular identification methods, bioactivity assays, and PCR screening for genes involved in antibiotics biosynthesis. 119 endophytic actinomycetes were recovered; 80 representative strains were chosen for 16S rRNA gene partial sequence analyses, with 66 of them being affiliated to genus Streptomyces and the remaining 14 strains being rare actinomycetes. Antimicrobial tests showed that 12 (15%) of the 80 endophytic actinomycetes displayed inhibitory effects against at least one indicator pathogens, which were all assigned to the genus Streptomyces. In addition, 87.5% and 58.8% of the isolates showed anticancer and anti-diabetic activities, respectively. Meanwhile, the anticancer activities of the isolates negatively correlated with their anti-diabetic activities. Based on the results of PCR screening, five genes, PKS-I, PKS-II, NRPS, ANSA, and oxyB, were detected in 55.0%, 58.8%, 90.0%, 18.8% and 8.8% of the 80 actinomycetes, respectively. In conclusion, the PCR screening method employed in the present study was conducive for screening and selection of potential actinomycetes and predicting potential secondary metabolites, which could overcome the limitations of traditional activity screening models. PMID:26721714

  2. Salmonella Typhimurium outbreak associated with a contaminated food container in a school in Sichuan Province, China.

    PubMed

    Liu, L G; Zhou, X Y; Lan, Z; Li, L; Li, Z; Chen, W; Wang, J Y; Zhang, L J

    2016-01-01

    On 13 June 2013, a fever and diarrhoea outbreak occurred in a boarding school in Sichuan Province. We conducted a field investigation and compared food exposure of 81 case students and 104 control students (years 7 and 8) in order to identify the source of infection. There were 401 cases identified (399 students and two cooks). The attack rates were 23-46% in nursery, primary, and secondary schools, but 0% in the high school. Eighty-five percent of case students, consumed cowpea salad compared to 60% of control students at lunch on 12 June (odds ratio 3·1, 95% confidence interval 1·3-7·8). The cowpeas were stored at room temperature for 3 h in a bucket previously used to store raw ingredients. The bucket was cleaned using water without a disinfectant. There were two buckets of cowpea, one for the high-school students and another for the other students. This Salmonella outbreak was likely caused by the cowpea salad due to cross-contamination via a storage bucket. PMID:26119077

  3. Electrophysiological evidence of personal experiences in the great Sichuan earthquake impacting on selective attention.

    PubMed

    Qiu, Jiang; Li, Hong; Zhang, QingLin; Huang, LiHui; Guo, YaQiao; Tu, Shen; Wang, Ting; Wei, DongTao

    2009-07-01

    Event-related brain potentials (ERPs) were measured when 24 Chinese subjects performed the earthquake color-matching Stroop task. All of them have experienced the great Sichuan earthquake (5.12), with 12 subjects in each of Chengdu city and Chongqing city (different earthquake experiences) groups. The behavioral data showed that the earthquake Stroop task yielded robust the earthquake interference effect as indexed by longer RT for earthquake-related (Related) words than earthquake-unrelated (Unrelated) words only in the Chengdu group. Scalp ERP analysis also revealed the neurophysiological substrate of the interference effect: a greater positivity (P350-450) in Related words as compared to Unrelated words was found between 350 and 450 ms post-stimulus over fronto-central scalp regions in the Chengdu group, while the interference effect was not found in the Chongqing group. The P350-450 might reflect an earthquake experience interference, but also attention enhancing, effect of earthquake-related words. Dipole source analysis of the difference wave (Related-Unrelated) showed that a generator was localized in the parahippocampal gyrus, which was possibly associated with flashbulb memory (personal earthquake experience). The results indicated that different personal earthquake experiences might be critical in engaging the neural mechanisms that underlie the modulation of selective attention. PMID:19641874

  4. Effect of target animacy on hand preference in Sichuan snub-nosed monkeys (Rhinopithecus roxellana).

    PubMed

    Zhao, Dapeng; Tian, Xiangling; Liu, Xinchen; Chen, Zhuoyue; Li, Baoguo

    2016-09-01

    Twenty-eight captive Sichuan snub-nosed monkeys (Rhinopithecus roxellana) were involved in the current study. Many individuals showed handedness, with a modest tendency toward left-hand use especially for animate targets, although no group-level handedness was found. There was no significant gender difference in the direction and strength of hand preference for both targets. Females showed a significantly higher overall rate of actions toward animate targets than inanimate targets for both hands, whereas males displayed almost the reversed pattern. There were no significant interactions between lateral hand use and target animacy for either males or females. Most individuals showed rightward or leftward laterality shift trends between inanimate and animate targets. These findings to some extent support the existence of a potential trend concerning a categorical neural distinction between targets demanding functional manipulation (inanimate objects) and those demanding social manipulation (animate objects), even though specialized hand preference based on target animacy has not been fully established in this arboreal Old World monkey species. PMID:27271775

  5. Toward sustainable and comprehensive control of schistosomiasis in China: lessons from Sichuan.

    PubMed

    Seto, Edmund Y W; Remais, Justin V; Carlton, Elizabeth J; Wang, Shuo; Liang, Song; Brindley, Paul J; Qiu, Dongchuan; Spear, Robert C; Wang, Long-De; Wang, Tian-Ping; Chen, Hong-Gen; Dong, Xing-Qi; Wang, Li-Ying; Hao, Yang; Bergquist, Robert; Zhou, Xiao-Nong

    2011-10-01

    Triggered by a fascinating publication in the New England Journal of Medicine detailing China's new multi-pronged strategy to control and eventually interrupt the transmission of Schistosoma japonicum, this PLoS Neglected Tropical Diseases Debate critically examines the generalizability and financial costs of the studies presented from the marshlands of the lake region. Edmund Seto from the University of California and colleagues emphasize that the epidemiology and control of schistosomiasis varies according to the social-ecological context. They conjecture that the successful intervention packages piloted in the lake region is not fully fit for the hilly and mountainous environments in Sichuan and Yunnan provinces, and hence call for more flexible, setting-specific, and less expensive control strategies. In response, Xiao-Nong Zhou from the National Institute of Parasitic Diseases at the Chinese Center of Disease Control and Prevention and colleagues explain the steps from designing pilot studies to the articulation and implementation of a new national control strategy through a careful process of scaling-up and adaptations. Finally, the two opponents converge. The need for integrated, intersectoral, and setting-specific control measures is stressed, supported by rigorous surveillance and continuous research. Experiences and lessons from China are important for shaping the schistosomiasis elimination agenda. PMID:22039563

  6. Factors Associated with Resilience of Adult Survivors Five Years after the 2008 Sichuan Earthquake in China

    PubMed Central

    Ni, Cuiping; Chow, Meyrick Chum Ming; Jiang, Xiaolian; Li, Sijian; Pang, Samantha Mei Che

    2015-01-01

    Given the paucity of quantitative empirical research on survivors’ resilience and its predictors in the context of long-term recovery after disasters, we examined how resilience predictors differed by gender among adult survivors five years after the Sichuan earthquake. This was a cross-sectional survey study of adult survivors (N = 495; aged 18–60) living in reconstructed communities five years into the recovery process after the Wenchuan earthquake. The instruments we used included assessments of sociodemographic characteristics and earthquake exposure level, the Connor-Davidson Resilience Scale, and the Social Support Rating Scale. Support-seeking behaviors emerged as a significant predictor of male survivors’ resilience, while subjective support and marital status were found to be predictors of female survivors’ resilience. Annual household income and chronic disease were predictors for both male and female groups. The findings of this study can be used in devising methods to boost survivors’ resilience by promoting their satisfaction with social support and their ability to obtain effective support. Additionally, the results suggest how to assist survivors who may have relatively poor resilience. PMID:25811775

  7. Survey of coccidial infection of rabbits in Sichuan Province, Southwest China.

    PubMed

    Yin, Guangwen; Goraya, Mohsan Ullah; Huang, Juhui; Suo, Xun; Huang, Zhijian; Liu, Xianyong

    2016-01-01

    Coccidiosis is a challenging disease of wild and domestic rabbits both, caused by Eimeria and thereby leads enormous economic losses at rabbit farms. The present study carried out to survey the prevalence and intensity of coccidial infection among the rabbits in Sichuan Province, southwest China. A total of 110 faecal samples were collected from 11 farms situated in eight main rabbits rearing administrative regions. Oocysts in faecal samples were purified, sporulated and identified according to morphological features. The overall prevalence of infection was 56.4 % (62/110), with prevalence of 64 % (47/75) for local meat breeds of rabbit and 51.4 % (18/35) for Rex Rabbits (local fur rabbits). Weanling rabbits had the highest prevalence (74 %, 37/50), followed by young rabbits (45 %, 13/29) and the adult rabbits showed the lowest prevalence (42 %, 13/31). Concurrent infection with two to seven Eimeria species was found. In total, 9 species of Eimeria were identified from oocyst-positive samples. E. perforans was the most prevalent specie (42.73 %), followed in order by Eimiera media, E. irresidua, E. magna, and E. intestinalis with prevalences of 35.45, 34.55, 31.82, and 23.64 %, respectively. Results of the present investigation indicated that the prevalence of coccidial infection is high among the rabbit population in southwest China. This study also elucidate about the coccidial infection and emphasis to adopt control strategies in commercial rabbitories. PMID:27386319

  8. Depression and posttraumatic stress disorder in temporary settlement residents 1 year after the Sichuan earthquake.

    PubMed

    Cheng, Zhang; Ma, Ning; Yang, Lei; Agho, Kingsley; Stevens, Garry; Raphael, Beverley; Cui, Lijun; Liu, Yongqiao; Yan, Baoping; Ma, Hong; Yu, Xin

    2015-03-01

    The authors sought to determine the prevalence and risk factors for major depressive disorder and posttraumatic stress disorder (PTSD) among survivors living in temporary accommodation in the Yongxing settlement in Mianyang city 1 year after the Sichuan earthquake for further interventions. They interviewed 182 residents, using the Structured Clinical Interview for DSM-IV Axis I Disorders and a self-report questionnaire. The 12-month prevalence of depressive disorder and PTSD were 48.9% and 39.6%, respectively. Multivariate analysis indicated that bereaved survivors were 5.51 times (adjusted odds ratio [AOR] = 5.51; 95% confidence interval [CI] =2.14-14.22) more likely to report PTSD and 2.42 times (AOR = 2.42; 95%CI =1.00-5.48) more likely to report depressive disorder than nonbereaved survivors. Older age and receipt of government financial support were significantly associated with 12-month PTSD. Depressive disorder 12 months after the earthquake was associated with receipt of government financial support, pre-earthquake physical illness, single marital status, being currently employed, and Han ethnicity. PMID:23666829

  9. Infant formula crisis in china: a cohort study in sichuan province.

    PubMed

    Tang, Li; Binns, Colin W; Lee, Andy H

    2015-03-01

    China has become the largest market of infant formula in the world. The consumption of infant formula is widespread across the country. This study investigated the opinions of Chinese mothers on infant formula. A prospective cohort study (n=695) was undertaken in 2011 in Sichuan province of China two years after the melamine scandal. Infant-feeding practices and mothers' opinions on infant formula-use were documented in detail. A total of 674 mothers (97%) had initiated breastfeeding by discharge. Of the 21 mothers who did not commence breastfeeding, 13 made a decision to exclusively feed their babies with infant formula because of hepatitis B virus infection. Nearly 70% of newborns received infant formula as their first feed, and the prevalence increased to 88% within one month. Having insufficient breastmilk was perceived by the majority (77%) of mothers as the reason behind infant formula feeding. About half (46%) of the mothers agreed with or were ambivalent that infant formula feeding does not reduce their breastmilk production. More than one-third (38%) of women thought that formulafed infants sleep longer at night than those who are breastfed. In addition, this perception was positively associated with the use of formula within one month postpartum (p=0.003). In conclusion, mothers' opinions appear to influence the use of infant formula in China. There is a need for further education on breastfeeding and infant-feeding options to maintain and improve breastfeeding outcomes in China. PMID:25995728

  10. Infant Formula Crisis in China: A Cohort Study in Sichuan Province

    PubMed Central

    Binns, Colin W.; Lee, Andy H.

    2015-01-01

    ABSTRACT China has become the largest market of infant formula in the world. The consumption of infant formula is widespread across the country. This study investigated the opinions of Chinese mothers on infant formula. A prospective cohort study (n=695) was undertaken in 2011 in Sichuan province of China two years after the melamine scandal. Infant-feeding practices and mothers’ opinions on infant formula-use were documented in detail. A total of 674 mothers (97%) had initiated breastfeeding by discharge. Of the 21 mothers who did not commence breastfeeding, 13 made a decision to exclusively feed their babies with infant formula because of hepatitis B virus infection. Nearly 70% of newborns received infant formula as their first feed, and the prevalence increased to 88% within one month. Having insufficient breastmilk was perceived by the majority (77%) of mothers as the reason behind infant formula feeding. About half (46%) of the mothers agreed with or were ambivalent that infant formula feeding does not reduce their breastmilk production. More than one-third (38%) of women thought that formulafed infants sleep longer at night than those who are breastfed. In addition, this perception was positively associated with the use of formula within one month postpartum (p=0.003). In conclusion, mothers’ opinions appear to influence the use of infant formula in China. There is a need for further education on breastfeeding and infant-feeding options to maintain and improve breastfeeding outcomes in China. PMID:25995728

  11. Is the Returning Farmland to Forest Program a Success? Three Case Studies from Sichuan

    PubMed Central

    Trac, Christine Jane; Schmidt, Amanda H.; Harrell, Stevan; Hinckley, Thomas M.

    2015-01-01

    China’s tuigeng huanlin or “Returning Farmland to Forest” (RFFP) program has been widely praised as the world’s largest and most successful payment for ecosystem services program, as well as a major contributor to China’s dramatic increase in forest cover from perhaps as low as 8% in 1960 to about 21% today. By compensating rural households for the conversion of marginal farmland to forestland and financing the afforestation of barren mountainsides, the program, in addition to expanding forestland, aims to reduce soil erosion and alleviate poverty. This paper presents qualitative and quantitative studies conducted on the local implementation of RFFP in three diverse townships in Sichuan. We find the actual results to be more mixed than the official figures would indicate. Though there have been some positive results, we identify problems with site and species selection, compensation for land taken out of cultivation, shift of labor to off-farm activities, and monitoring of replanted sites, which challenge the ecological and economic impacts of these programs and reveal much of the effort of the program has been misdirected. We suggest that efforts are misplaced because of the top-down, panacea nature of the program, which in turn is a feature of Chinese bureaucratic management. PMID:26213492

  12. Comparison of two large earthquakes: the 2008 Sichuan Earthquake and the 2011 East Japan Earthquake.

    PubMed

    Otani, Yuki; Ando, Takayuki; Atobe, Kaori; Haiden, Akina; Kao, Sheng-Yuan; Saito, Kohei; Shimanuki, Marie; Yoshimoto, Norifumi; Fukunaga, Koichi

    2012-01-01

    Between August 15th and 19th, 2011, eight 5th-year medical students from the Keio University School of Medicine had the opportunity to visit the Peking University School of Medicine and hold a discussion session titled "What is the most effective way to educate people for survival in an acute disaster situation (before the mental health care stage)?" During the session, we discussed the following six points: basic information regarding the Sichuan Earthquake and the East Japan Earthquake, differences in preparedness for earthquakes, government actions, acceptance of medical rescue teams, earthquake-induced secondary effects, and media restrictions. Although comparison of the two earthquakes was not simple, we concluded that three major points should be emphasized to facilitate the most effective course of disaster planning and action. First, all relevant agencies should formulate emergency plans and should supply information regarding the emergency to the general public and health professionals on a normal basis. Second, each citizen should be educated and trained in how to minimize the risks from earthquake-induced secondary effects. Finally, the central government should establish a single headquarters responsible for command, control, and coordination during a natural disaster emergency and should centralize all powers in this single authority. We hope this discussion may be of some use in future natural disasters in China, Japan, and worldwide. PMID:22410538

  13. Gender and HIV risk behavior among intravenous drug users in Sichuan Province, China.

    PubMed

    Choi, Susanne Y P; Cheung, Yuet Wah; Chen, Kanglin

    2006-04-01

    Using data from a community-based study of injection drug users (IDUs) in Sichuan Province in China, this study compared the level of HIV risk behavior (needle sharing and unsafe sex) amongst female and male IDUs, and examined the risk factors separately for these two groups. Five risk factors were examined in the analysis, including a lack of family support, having an IDU primary sex partner, economic pressure, lack of access to a methadone program, and younger age. Regression results showed that male and female IDUs had different risk factors. For male IDUs, younger age and a lack of family support increased their level of HIV risk behavior. For female IDUs, having an IDU primary sex partner and economic pressure were predictive of their HIV risk behavior. Sex differences in risk factors are explained with respect to gender norms surrounding HIV risk behavior in the context of social relations. Female IDUs who were sex workers suffered additional HIV risk due to their powerlessness in negotiating safe sex with male customers. Practical implications of the findings for HIV/AIDS prevention and intervention work in China are discussed. PMID:16185801

  14. Genetic diversity and population structure of a Sichuan sika deer (Cervus sichuanicus) population in Tiebu Nature Reserve based on microsatellite variation

    PubMed Central

    HE, Ya; WANG, Zheng-Huan; WANG, Xiao-Ming

    2014-01-01

    Cervus sichuanicus is a species of sika deer (Cervus nippon Group). To date, research has mainly focused on quantity surveying and behavior studies, with genetic information on this species currently deficient. To provide scientific evidence to assist in the protection of this species, we collected Sichuan sika deer fecal samples from the Sichuan Tiebu Nature Reserve (TNR) and extracted DNA from those samples. Microsatellite loci of bovine were used for PCR amplification. After GeneScan, the genotype data were used to analyze the genetic diversity and population structure of the Sichuan sika deer in TNR. Results showed that the average expected heterozygosity of the Sichuan sika deer population in TNR was 0.562, equivalent to the average expected heterozygosity of endangered animals, such as Procapra przewalskii. Furthermore, 8 of 9 microsatellite loci significantly deviated from the Hardy-Weinberg equilibrium and two groups existed within the Sichuan sika deer TNR population. This genetic structure may be caused by a group of Manchurian sika deer (Cervus hortulorum) released in TNR. PMID:25465089

  15. Genetic diversity and population structure of a Sichuan sika deer (Cervus sichuanicus) population in Tiebu Nature Reserve based on microsatellite variation.

    PubMed

    He, Ya; Wang, Zheng-Huan; Wang, Xiao-Ming

    2014-11-18

    Cervus sichuanicus is a species of sika deer (Cervus nippon Group). To date, research has mainly focused on quantity surveying and behavior studies, with genetic information on this species currently deficient. To provide scientific evidence to assist in the protection of this species, we collected Sichuan sika deer fecal samples from the Sichuan Tiebu Nature Reserve (TNR) and extracted DNA from those samples. Microsatellite loci of bovine were used for PCR amplification. After GeneScan, the genotype data were used to analyze the genetic diversity and population structure of the Sichuan sika deer in TNR. Results showed that the average expected heterozygosity of the Sichuan sika deer population in TNR was 0.562, equivalent to the average expected heterozygosity of endangered animals, such as Procapra przewalskii. Furthermore, 8 of 9 microsatellite loci significantly deviated from the Hardy-Weinberg equilibrium and two groups existed within the Sichuan sika deer TNR population. This genetic structure may be caused by a group of Manchurian sika deer (Cervus hortulorum) released in TNR. PMID:25465089

  16. Western gas sands

    SciTech Connect

    Not Available

    1985-03-01

    The purpose of this research is to demonstrate the feasibility of economically producing natural gas from low-permeability reservoirs. Two broad research goals have been defined: (1) reducing the uncertainty of the reservoir production potential, and (2) improving the extraction technology. These goals are being pursued by conducting research and encouraging industrial efforts in developing the necessary technology, including: (1) providing fundamental research into the nature of tight, lenticular gas sands and the technologies for diagnosing and developing them: (2) developing and verifying the technology for effective gas production; and (3) promoting the transfer of research products and technology advances to the gas industry in usable forms. The focus of the research for the last several years has been improving diagnostic instrumentation for reservoir and stimulation performance evaluation, geophysical and engineering interpretation, and stimulation techniques. Integrated geologic studies of three basins containing tight lenticular sands, which were selected by DOE as priority research targets, have also been pursued as part of this new effort. To date, the following tentative conclusions have been formed: Permeability of the tight gas sands can be as much as three to four orders of magnitude lower than that of conventional gas deposits. Nineteen western geologic basins and trends containing significant volumes of tight gas have been identified. Gas resources in the priority geologic basins have been estimated - Piceance Basin 49 Tcf.; Greater Green River Basin, 136 Tcf.; Uinta Basin, 20 Tcf. Presence of natural micro-fractures within a reservoir and the effective propped length of hydraulically induced fratures are the critical parameters for successful development of tight sand resources. Stimulation technology at the present time is insufficient to efficiently recover gas from lenticular tight reservoirs. 8 figs., 3 tabs.

  17. Depositional setting of the Upper Jurassic Hith Anhydrite of the Arabian Gulf: An analog to holocene evaporites of the United Arab Emirates and Lake MacLeod of Western Australia

    SciTech Connect

    Alsharhan, A.S. ); Kendall, C.G.St.C. )

    1994-07-01

    The Upper Jurassic Hith Anhydrite is a major hydrocarbon seal in the Arabian Gulf region. Outcrops, core samples from the subsurface, and the literature indicate that the Hith Formation is composed mainly of anhydrite. In most locations where a section of the Hith Formation has been measured, this unit contains less than 20% carbonate much of which is in the form of thin laminations. This lack of carbonate, locally thick layers of salt, and the predominance of anhydrite favor a playa for the setting in which this sediment was accumulated. In fact, much of the Hith has the sedimentary characteristics of the Holocene Lake MacLeod playa of Western Australia, which is dominated by layers of gypsum and halite (what little carbonate that occurs is found in layers at the base of the section). Locally the Hith appears to have accumulated in a sabkha setting, particularly toward central Abu Dhabi where it pinches out into shallow-water, and peritidal carbonate. This sabkha setting is indicated by the interbedded relationship of the Hith anhydrites with these carbonates and the local predominance of horizontally flattened nodules and enterolithic layers of anhydrite. These latter features match some of the characteristic fabrics found in the Holocene coastal sabkhas of the United Arab Emirates. As with the local occurrences in the Hith, the Holocene sabkhas are dominated by carbonates and are divisible into a series of lateral facies belts. These are also expressed as equivalent vertical layers. Traced from seaward to landward, or from the base of the vertical sequence upward, these facies are characterized by (1) algal mat, (2) a layer of a gypsum crystal mush (3) active anhydrite replacement of gypsum (4) anhydrite with no gypsum mush, and (5) recycled eolianite and storm-washover sediments.

  18. Geological, rare earth elemental and isotopic constraints on the origin of the Banbanqiao Zn-Pb deposit, southwest China

    NASA Astrophysics Data System (ADS)

    Li, Bo; Zhou, Jia-Xi; Huang, Zhi-Long; Yan, Zai-Fei; Bao, Guang-Ping; Sun, Hai-Rui

    2015-11-01

    The newly discovered Banbanqiao Zn-Pb deposit in the southeastern part of the Sichuan-Yunnan-Guizhou (SYG) Pb-Zn metallogenic province is located on the western Yangtze Block, southwest China. Ore bodies of the Banbanqiao deposit are stratiform type, host in dolomitic limestone and dolostone of the Lower Carboniferous Dapu Formation and occur within the NNE-trending Banbanqiao anticline. More than 1.5 million tones (Mt) Zn-Pb ores at grades of 0.26-10.32 wt.% Pb and 0.81-28.8 wt.% Zn have been controlled until now. δ13CPDB and δ18OSMOW values of calcite separates range from -2.8‰ to -0.7‰ (average -1.1‰) and +14.1‰ to +17.0‰ (average +15.5‰), respectively. The δ13CPDB values are similar to those of marine carbonate rocks, but higher than those of mantle and significantly different from those of sedimentary organic matter. However, the δ18OSMOW values are among those of mantle, marine carbonate rocks and sedimentary organic matter. δ34SCDT values of sulfide separates range from +3.2‰ to +9.9‰ (average +6.5‰), unlike mantle-derived sulfur (0 ± 3‰), whilst lower than evaporites (+22‰ to +28‰) within host strata. 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values of country shale and dolostone whole-rock samples are 18.47, 15.66 and 38.70, and 18.44-18.60, 15.66-15.85 and 38.70-39.14, respectively. Sulfide separates have 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values ranging from 18.03 to 18.73, 15.65 to 15.78 and 38.15 to 39.14, respectively. These Pb isotopic data indicate a clearly crustal source of Pb in the plot of 207Pb/204Pb vs. 206Pb/204Pb. Total REE (ΣREE) contents of country shale and dolostone whole-rock samples are 2.63 ppm and 0.72-86.2 ppm with δEu values are 2.79 and 0.34-0.70, respectively. Pyrite, sphalerite, galena and calcite samples have ΣREE contents of 5.3-36.4 ppm, 0.29-3.39 ppm, 0.52 ppm and 22.0-41.1 ppm, respectively, and δEu values of 0.64-0.86, 0.94-2.86, 0.32 and 0.21-0.45, respectively. These rare earth

  19. Molecular and phylogenetic analysis of the porcine kobuvirus VP1 region using infected pigs from Sichuan Province, China

    PubMed Central

    2013-01-01

    Background Porcine kobuvirus (PKoV) is a member of the Kobuvirus genus within the Picornaviridae family. PKoV is distributed worldwide with high prevalence in clinically healthy pigs and those with diarrhea. Methods Fecal and intestinal samples (n = 163) from pig farms in Sichuan Province, China were obtained to determine the presence of PKoV using reverse transcription polymerase chain reaction assays. Specific primers were used for the amplification of the gene encoding the PKoV VP1 protein sequence. Sequence and phylogenetic analyses were conducted to clarify evolutionary relationships with other PKoV strains. Results Approximately 53% (87/163) of pigs tested positive for PKoV. PKoV was widespread in asymptomatic pigs and those with diarrhea. A high prevalence of PKoV was observed in pigs younger than 4 weeks and in pigs with diarrhea. Phylogenetic analysis of 36 PKoV VP1 protein sequences showed that Sichuan PKoV strains formed four distinct clusters. Two pigs with diarrhea were found to be co-infected with multiple PKoV strains. Sequence and phylogenetic analyses revealed diversity within the same host and between different hosts. Significant recombination breakpoints were observed between the CHN/SC/31-A1 and CHN/SC/31-A3 strains in the VP1 region, which were isolated from the same sample. Conclusion PKoV was endemic in Sichuan Province regardless of whether pigs were healthy or suffering from diarrhea. Based on our statistical analyses, we suggest that PKoV was the likely causative agent of high-mortality diarrhea in China from 2010. For the first time, we provide evidence for the co-existence of multiple PKoV strains in one pig, and possible recombination events in the VP1 region. Our findings provide further insights into the molecular properties of PKoV, along with its epidemiology. PMID:24025093

  20. The Prevalence of Distress and Depression among Women in Rural Sichuan Province

    PubMed Central

    Qiu, Peiyuan; Caine, Eric D.; Hou, Fengsu; Cerulli, Catherine; Wittink, Marsha N.; Li, Jin

    2016-01-01

    Background In this paper, we report findings regarding the prevalence of expressed distress and depressive conditions among women living in a rural region of Sichuan Province. As well, we know of no data among women in rural China that examine whether “depression,” as categorically defined in classifications such as the DSM, adequately captures the expressed distress and symptomatic complaints of women in rural China. Methods A multistage sampling method was employed to recruit the target population. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to measure distress symptoms, and MINI International Neuropsychiatric Interview (MINI) was employed to determine the prevalence of diagnosable depression and other disorders. Results Among 1898 rural women, 12.4% (236) scored ≥16 on the CES-D, indicative of distress, and a subset of 7.7% (146) had scores ≥21, highly suggestive of a clinically significant disorder. We found that 49.8% women with ≥16 CES-D score were identified as showing features consistent with a current major depressive episode (MDE) vs. 1.9% in a sample of randomly selected women with <16 CES-D score. Among respondents, 30 of 84 (35.7%) scoring 16–20 and 83 of 143 (58.0%) scoring ≥21 reported symptoms consistent with MDE. 25.1% of women with a positive CES-D score did not describe symptoms consistent with any DSM-IV disorder. Conclusions We found a higher portion of women reporting significant distress than previously described. Among them, there was a clear gradient, such that 41.7% of women with moderate distress did not have a psychiatric diagnosis, and even among those with more severe symptoms, 15.4% did not manifest a DSM-specific psychiatric condition. PMID:27526182

  1. Total Vertical Offset for the Beichuan Fault (Longmen Shan, Sichuan, China) Deduced from Metamorphic Minerals

    NASA Astrophysics Data System (ADS)

    Airaghi, L.; de Sigoyer, J.; Vidal, O.; Lanari, P.; Tan, X. B.; Xu, X.; Guillot, S.

    2015-12-01

    The paradox of high topography but low convergence rates in the Longmen Shan mountain belt, at the eastern margin of Tibetan plateau (Sichuan, China) leaded to an underestimation of the seismic hazard prior to the Wenchuan earthquake Mw 7.9 (2008). The rupture affected the crustal Beichuan fault, with both thrusting and dextral slide slip components. This fault is responsible for the exhumation of the basement over Triassic sediments. Several paleoseismological studies have well constrained the Quaternary activity of this fault, and thermochronological data show a rapid exhumation starting from Oligocene. The total offset of the Beichuan fault remains unknown. Samples collected in the hanging wall of the Beichuan fault, yield stable white mica, chlorite, epidote and quartz. Chemical and thermobarometric analyses of metamorphic minerals yield metamorphic peak conditions at 300±50°C and 7-8 kbar. Such P,T conditions suggest burial to 18-20 km depth, and represent the maximum vertical offset of the Beichuan fault. Comparison of results from distant sampled sites along the Beichuan fault reveals the spatial continuity of this offset along the Beichuan fault. The attainment of peak pressure conditions will be dated using in-situ laser ablation 40Ar/39Ar dating of the metamorphic micas. This will help constrain the onset of Beichuan fault activation, which corresponds to the onset of thick skin deformation in the Longmen Shan. [CW1]I deleted all this stuff below because I thought it was too much information for a conference abstract - but you do have space to put it back.

  2. Culturally appropriate nutrition education improves infant feeding and growth in rural Sichuan, China.

    PubMed

    Guldan, G S; Fan, H C; Ma, X; Ni, Z Z; Xiang, X; Tang, M Z

    2000-05-01

    Chinese studies indicate that the growth of rural infants and children lags behind that of their urban counterparts after 4 mo of age and that the gap is widening. However, the rural areas are home to >85% of China's 300 million children. Clearly, culturally appropriate rural complementary feeding interventions are needed to close the growth and health gaps. After a 1990 survey of infants in rural Sichuan confirmed that poor infant feeding practices rather than inadequate household food resources were responsible for the growth faltering, a year-long community-based pilot nutrition education intervention (n congruent with 250 infants each in Education and Control groups) was undertaken in four townships. The goal was to improve infant growth by improving infant feeding practices. Features of the intervention included the training and mobilizing of village nutrition educators who made monthly growth monitoring and complementary feeding counseling visits to all pregnant women and families with infants born during the intervention in the study villages. After 1 y, the Education group mothers showed significantly higher nutrition knowledge and better reported infant feeding practices than their Control group counterparts. Also, the Education group infants were significantly heavier and longer, but only at 12 mo (weight-for-age -1.17 vs. -1.93; P = 0.004; height-for-age -1.32 vs. -1.96; P = 0.022), had higher breast-feeding rates overall (83% vs. 75%; P = 0.034) and lower anemia rates (22% vs. 32%; P = 0.008) than the Control group infants. We conclude that these methods have potential for adaptation and development to other rural areas in the county, province and nation. PMID:10801920

  3. Resource Assessment for Xu jiahe formation of Chuanzhong District in Sichuan Basin

    NASA Astrophysics Data System (ADS)

    Hu, Junwen; Guo, Giulin

    2016-04-01

    Xu-2, the second member of Xu jiahe formation of Chuanzhong district in Sichuan Basin, is the tight sandstone gas reservoirs. The sum of conventional gas traps was used to evaluate it before, but the evaluation results are not reasonable enough. According to the characteristics of great-area continuous tight sandstone gas, this paper puts forward a kind of resource abundance analogy method to research the distribution of gas reservoirs and resources potential of Xu-2 of chuanzhong district. Firstly, we build 18 scale areas of tight sandstone gas accumulation at home and abroad and use relevance analysis and parameters preference skills to confirm the key parameters and set up the parameter evaluation system and determine the criterion of the parameters. Then, based on the analysis of conditions for tight gas accumulation of Xu-2, second member of Xu jiahe formation, Chuanzhong district(area 40000km2)is divided into 10 blocks, we contrast scale areas of tight sandstone gas accumulation with the blocks respectively, and calculate the related coefficient of analogy, finally compute resource of each block. The results demonstrate that: the total tight sandstone gas resources in Xu-2 reach to about 2,200 billion cubic meters, and the resource enrichment value is about 0.05 billion m3/km2, which shows the bright prospect of exploration of tight sandstone gas. There are high abundance gas reservoirs around the areas of A-B-C and D-E-F, and abundance values have reached to 0.12 billion m3/km2 and 0.11 billion m3/km2 respectively, which provides the directions for exploration of tight sandstone gas in Chuanzhong district.

  4. Limited and localized outbreak of newly emergent type 2 vaccine-derived poliovirus in Sichuan, China.

    PubMed

    Yan, Dongmei; Zhang, Yong; Zhu, Shuangli; Chen, Na; Li, Xiaolei; Wang, Dongyan; Ma, Xiaozhen; Zhu, Hui; Tong, Wenbin; Xu, Wenbo

    2014-07-01

    From August 2011 to February 2012, an outbreak caused by type 2 circulating vaccine-derived poliovirus (cVDPV) occurred in Aba County, Sichuan, China. During the outbreak, four type 2 VDPVs (≥0.6% nucleotide divergence in the VP1 region relative to the Sabin 2 strain) were isolated from 3 patients with acute flaccid paralysis (AFP) and one close contact. In addition, a type 2 pre-VDPV (0.3% to 0.5% divergence from Sabin 2) that was genetically related to these type 2 VDPVs was isolated from another AFP patient. These 4 patients were all unimmunized children 0.7 to 1.1 years old. Nucleotide sequencing revealed that the 4 VDPV isolates differed from Sabin 2 by 0.7% to 1.2% in nucleotides in the VP1 region and shared 5 nucleotide substitutions with the pre-VDPV. All 5 isolates were closely related, and all were S2/S3/S2/S3 recombinants sharing common recombination crossover sites. Although the two major determinants of attenuation and temperature sensitivity phenotype of Sabin 2 (A481 in the 5' untranslated region and Ile143 in the VP1 protein) had reverted in all 5 isolates, one VDPV (strain CHN16017) still retained the temperature sensitivity phenotype. Phylogenetic analysis of the third coding position of the complete P1 coding region suggested that the cVDPVs circulated locally for about 7 months following the initiating oral poliovirus vaccine (OPV) dose. Our findings reinforce the point that cVDPVs can emerge and spread in isolated communities with immunity gaps and highlight the emergence risks of type 2 cVDPVs accompanying the trivalent OPV used. To solve this issue, it is recommended that type 2 OPV be removed from the trivalent OPV or that inactivated polio vaccine (IPV) be used instead. PMID:24850620

  5. River capture by earthquake caused the transition of ancient Sichuan civilizations

    NASA Astrophysics Data System (ADS)

    Fan, N.; Wu, B.; Nie, R.; Liu, X.; Cao, S.

    2014-12-01

    About three thousand years ago, Sanxingdui Civilization in Sichuan, China suddenly disappeared in its flourishing stage, following by a new Civilization called Jinsha locates about 40 kilometers southwest of Sanxingdui. The previous reasons such as flood or war was not so convincing to explain the sudden extinction of Sanxingdui and the heritage of Jinsha. Nevertheless, no sufficient attention has been paid to the special geomorphologic characters of Yanmen Ravine (a tributary of Minjiang River), Jianjiang River and Baishui River (a tributary of Jianjiang River), either. Based on field investigation conducted in the relevant areas, in addition with 3S (Remote Sensing RS, Geographical information System GIS and Global Positioning System GPS) technologies, it is found that Yanmen Ravine, Baishui River and Jianjiang River (all are bed rock rivers) are too wide in according with the small flow discharge. Some cirques locate in high areas of Mount Gauangguang, which is the divide of the current Yanmen Ravine and Baishui River, but no cirques exist near the proposed old channel. As a result, it proves that Baishui River and Jianjiang River are beheaded rivers and Yanmen Ravine is a reversed river. All the demonstrations above prove that Minjiang River used to flow southeast into Tuojiang River through Mount Guangguang along Baishui River and Jianjiang River. The profiles of Minjing River, Zagunao River, Yanmen Ravine and Wenzheng Ravine also demonstrate that river capture once happened. Combining historic records and archaeological materials, it is concluded that a strong earthquake happened in 1099B.C. triggered rock avalanches and landslides, the old Minjiang River was dammed in Mount Guangguang and river capture happened. The avulsion of river resulted in sharp decreasing of the flow discharge of the river flowing by Sanxingdui Civilization. As a result, for the short of water resources, Sanxingdui Civilization was forced to migrate and finally found the big river in

  6. An Investigation on Self-Rated Health of Adolescent Students and Influencing Factors From Sichuan, China

    PubMed Central

    Zhang, Fengying; Zhao, Li; Feng, Xianqiong; Hu, Xiuying

    2016-01-01

    To investigate adolescent students' self-rated health status and to identify the influencing factors that affect students' health status. A stratified cluster sampling method and the Self-assessed General Health Questionnaires were used to enroll 503 adolescent students from Sichuan Province, Southwest part of China. Most adolescent students perceived their self-rated health as “Fair” (29.4%), “Good” (52.1%), or “Very Good” (16.3%). Regarding the sleep quality, most of them rated them as “Fair” (24.9%), “Good” (43.1%), or “Very Good” (19.7%), but 59.7% students reported to sleep less than 8 hours a day, even a few reported to sleep less than 6 hours (4.4%) or more than 9 hours (9.7%). A considerable number of students (41.1%) reported that they “Never” or just “Occasionally” participated in appropriate sports or exercises. As to the dietary habit, a significant number of students (15.7%) reported that they “Never” or “Occasionally” have breakfast. Students from different administrative levels of schools (municipal level, county level, and township level) rated differently (P < 0.05) in terms of their self-rated health, Health Behaviors, Sleeping, Dietary behaviors, Safety Awareness, and Drinking and Smoking behaviors. In general, Chinese teenage students perceived their own health status as fairly good. However, attention needs to be paid to health problems of some of the students, such as lack of sleep and exercise and inadequate dietary habits, etc. More concerns need to be addressed to students from different administrative levels of schools, and strategies should be put forward accordingly. PMID:27058576

  7. Application of Time Series Insar Technique for Deformation Monitoring of Large-Scale Landslides in Mountainous Areas of Western China

    NASA Astrophysics Data System (ADS)

    Qu, T.; Lu, P.; Liu, C.; Wan, H.

    2016-06-01

    Western China is very susceptible to landslide hazards. As a result, landslide detection and early warning are of great importance. This work employs the SBAS (Small Baseline Subset) InSAR Technique for detection and monitoring of large-scale landslides that occurred in Li County, Sichuan Province, Western China. The time series INSAR is performed using descending scenes acquired from TerraSAR-X StripMap mode since 2014 to get the spatial distribution of surface displacements of this giant landslide. The time series results identify the distinct deformation zone on the landslide body with a rate of up to 150mm/yr. The deformation acquired by SBAS technique is validated by inclinometers from diverse boreholes of in-situ monitoring. The integration of InSAR time series displacements and ground-based monitoring data helps to provide reliable data support for the forecasting and monitoring of largescale landslide.

  8. Implication of fault interaction to seismic hazard assessment in Sichuan-Yunnan provinces of Southeastern China

    NASA Astrophysics Data System (ADS)

    Gkarlaouni, C.; Papadimitriou, E. E.; Karakostas, V. G.; Wen, Xue–Ze; Jin, Xue–Shen; Kilias, A.; Pan, Hua

    2009-04-01

    Strong seismicity in China and adjacent regions is distributed over specific zones that configure rigid lithospheric subplates often bounded by active faults. Sichuan and Yunnan provinces correspond to a so-called rhombic shaped subplate that experiences the strongest intraplate seismicity in the territory of China. The region exhibits a complicated tectonic regime that consists of various rupture zones and different faulting types with strike slip prevailing, consistent with the regional stress field and geological background. During the 20th century, 35 devastating earthquakes with magnitude Ms≥6.5 occurred nearby densely populated areas causing a majority of casualties and deaths. The fact that Sichuan and Yunnan provinces are densely populated and industrially developed urges the necessity for investigating the occurrence pattern of the region's stronger events through the stress evolutionary model and also identifying the structures that are apt to produce a potential strong seismic event in the future. The tectonic complexity reveals a real challenge for our investigation, since the interaction is sought among different faulting types. Stress transfer seems not to be restricted in a single however segmented fault but also expands over the adjacent faults or conjugate zones often bringing them toward rupture. The characteristic of the tectonic setting is that various long strike slip, normal and some thrust faults exist within the same area, interacting with each other. Such interaction of strong earthquakes has been proved by previous investigation concerning the Xianshuihe fault zone (Papadimitriou et al., 2004) and the stress evolution for the northeast Tibetan Plateau from 1920 till present for a viscoelastic model (Wan et al., 2007). A feature characterizing long fault zones is that they are found segmented and distinct parts of faults rupture each time until they complete a seismic cycle. Although fault surfaces are irregular and ruptures are more

  9. What Is Western Civilization?

    ERIC Educational Resources Information Center

    Birken, Lawrence

    1992-01-01

    Discusses opposing tendencies in the interpretation of Western Civilization. Describes the expanded definition that includes Byzantine and Islamic cultures as heirs of the Greco-Roman cultures. Suggests that a limited definition of Western culture will facilitate a problems approach, emphasize diversity among cultures, and integrate the classical…

  10. Molecular and phenotypic characterization of Colletotrichum species associated with anthracnose disease in peppers from Sichuan Province, China

    PubMed Central

    Liu, Fangling; Tang, Guiting; Zheng, Xiaojuan; Li, Ying; Sun, Xiaofang; Qi, Xiaobo; Zhou, You; Xu, Jing; Chen, Huabao; Chang, Xiaoli; Zhang, Sirong; Gong, Guoshu

    2016-01-01

    The anthracnose caused by Colletotrichum species is an important disease that primarily causes fruit rot in pepper. Eighty-eight strains representing seven species of Colletotrichum were obtained from rotten pepper fruits in Sichuan Province, China, and characterized according to morphology and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) sequence. Fifty-two strains were chosen for identification by phylogenetic analyses of multi-locus sequences, including the nuclear ribosomal internal transcribed spacer (ITS) region and the β-tubulin (TUB2), actin (ACT), calmodulin (CAL) and GAPDH genes. Based on the combined datasets, the 88 strains were identified as Colletotrichum gloeosporioides, C. siamense, C. fructicola, C. truncatum, C. scovillei, and C. brevisporum, and one new species was detected, described as Colletotrichum sichuanensis. Notably, C. siamense and C. scovillei were recorded for the first time as the causes of anthracnose in peppers in China. In addition, with the exception of C. truncatum, this is the first report of all of the other Colletotrichum species studied in pepper from Sichuan. The fungal species were all non-host-specific, as the isolates were able to infect not only Capsicum spp. but also Pyrus pyrifolia in pathogenicity tests. These findings suggest that the fungal species associated with anthracnose in pepper may inoculate other hosts as initial inoculum. PMID:27609555

  11. Spatio-Temporal Pattern and Socio-Economic Factors of Bacillary Dysentery at County Level in Sichuan Province, China.

    PubMed

    Ma, Yue; Zhang, Tao; Liu, Lei; Lv, Qiang; Yin, Fei

    2015-01-01

    Bacillary dysentery (BD) remains a big public health problem in China. Effective spatio-temporal monitoring of BD incidence is important for successful implementation of control and prevention measures. This study aimed to examine the spatio-temporal pattern of BD and analyze socio-economic factors that may affect BD incidence in Sichuan province, China. Firstly, we used space-time scan statistic to detect the high risk spatio-temporal clusters in each year. Then, bivariate spatial correlation and Bayesian spatio-temporal model were utilized to examine the associations between the socio-economic factors and BD incidence. Spatio-temporal clusters of BD were mainly located in the northern-southern belt of the midwest area of Sichuan province. The proportion of primary industry, the proportion of rural population and the rates of BD incidence show statistically significant positive correlation. The proportion of secondary industry, proportion of tertiary Industry, number of beds in hospitals per thousand persons, medical and technical personnel per thousand persons, per capital GDP and the rate of BD incidence show statistically significant negative correlation. The best fitting spatio-temporal model showed that medical and technical personnel per thousand persons and per capital GDP were significantly negative related to the risk of BD. PMID:26469274

  12. Molecular and phenotypic characterization of Colletotrichum species associated with anthracnose disease in peppers from Sichuan Province, China.

    PubMed

    Liu, Fangling; Tang, Guiting; Zheng, Xiaojuan; Li, Ying; Sun, Xiaofang; Qi, Xiaobo; Zhou, You; Xu, Jing; Chen, Huabao; Chang, Xiaoli; Zhang, Sirong; Gong, Guoshu

    2016-01-01

    The anthracnose caused by Colletotrichum species is an important disease that primarily causes fruit rot in pepper. Eighty-eight strains representing seven species of Colletotrichum were obtained from rotten pepper fruits in Sichuan Province, China, and characterized according to morphology and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) sequence. Fifty-two strains were chosen for identification by phylogenetic analyses of multi-locus sequences, including the nuclear ribosomal internal transcribed spacer (ITS) region and the β-tubulin (TUB2), actin (ACT), calmodulin (CAL) and GAPDH genes. Based on the combined datasets, the 88 strains were identified as Colletotrichum gloeosporioides, C. siamense, C. fructicola, C. truncatum, C. scovillei, and C. brevisporum, and one new species was detected, described as Colletotrichum sichuanensis. Notably, C. siamense and C. scovillei were recorded for the first time as the causes of anthracnose in peppers in China. In addition, with the exception of C. truncatum, this is the first report of all of the other Colletotrichum species studied in pepper from Sichuan. The fungal species were all non-host-specific, as the isolates were able to infect not only Capsicum spp. but also Pyrus pyrifolia in pathogenicity tests. These findings suggest that the fungal species associated with anthracnose in pepper may inoculate other hosts as initial inoculum. PMID:27609555

  13. Organochlorine pesticide residues in surface water from Sichuan Basin to Aba Prefecture profile, east of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, Hongxia; Hu, Ying; Qi, Shihua; Xing, Xinli; Zhang, Yuan; Yang, Dan; Qu, Chengkai

    2014-09-01

    Organochlorine pesticides (OCPs) found in rivers from the Sichuan Basin to Aba Prefecture profile were analyzed to assess possible health risks to adults and children who use the river as a source of drinking water. OCP concentrations in surface water ranged between 22.29-274.28 ng·L-1. Compared with other published data around the world, OCP levels in this study were moderate. Among all OCPs, hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) were the predominant compounds. Higher concentrations of OCPs were attributed close to the agricultural fields of the Sichuan Basin, current OCPs inputs, and long-range atmospheric transport from abroad. Various spatial patterns of OCPs in the profile might be affected by the usage and physicochemical properties of the pesticides, in addition to the adjacent geographical environment. The health risk assessment indicated that most OCPs had little impact on human health according to the acceptable risk level for carcinogens (10-6) recommended by the US EPA. However, carcinogenic effects caused by heptachlor, Aldrin, HCB, and α-HCH might occur in drinking water. The risk of negative impacts caused by OCPs is much higher for children than for adults.

  14. Morphological and molecular taxonomic analysis of Pseudopoda Jäger, 2000 (Araneae: Sparassidae: Heteropodinae) in Sichuan Province, China.

    PubMed

    Jäger, Peter; Li, Shuqiang; Krehenwinkel, Henrik

    2015-01-01

    The genus Pseudopoda Jäger, 2000 is revised from material collected in Sichuan province. A molecular analysis shows the utility of DNA markers to support taxonomic hypotheses in Sparassidae. Two new species are described: Pseudopoda coenobium spec. nov. from Emeishan (male, female) and Pseudopoda wu spec. nov. from Lugu Lake at the border to Yunnan (male, female). The latter species exhibits a unique reduction of the conductor and a strongly developed embolus. The female of Pseudopoda virgata (Fox, 1936) is described for the first time, the male is redescribed, the known range of the geographical distribution is considerably extended to the East (Baoxing and Tienqiang County), the vertical distribution range is extended from 300 m to slightly more than 2000 m. The male of Pseudopoda signata Jäger, 2001 is described for the first time, the female is redescribed, the known distribution range of this species is extended from Muge Cuo Lake over Kangding town to the valleys of Paomashan, Gonggashan and Yanzi. It shows a strong morphological variation, which may be interpreted as developing subspecies status in different valleys. However, according to results from a molecular analysis it is clearly considered intraspecific variability. Three further species are recorded from Sichuan: Pseudopoda emei Zhang et al., 2013, Pseudopoda sp. cf. yunnanensis (Yang & Hu, 2001) and Pseudopoda rivicola Jäger and Vedel, 2007. PMID:26623582

  15. Organochlorine pesticide residues in surface water from Sichuan Basin to Aba Prefecture profile, east of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, Hongxia; Hu, Ying; Qi, Shihua; Xing, Xinli; Zhang, Yuan; Yang, Dan; Qu, Chengkai

    2015-06-01

    Organochlorine pesticides (OCPs) found in rivers from the Sichuan Basin to Aba Prefecture profile were analyzed to assess possible health risks to adults and children who use the river as a source of drinking water. OCP concentrations in surface water ranged between 22.29-274.28 ng·L-1. Compared with other published data around the world, OCP levels in this study were moderate. Among all OCPs, hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) were the predominant compounds. Higher concentrations of OCPs were attributed close to the agricultural fields of the Sichuan Basin, current OCPs inputs, and long-range atmospheric transport from abroad. Various spatial patterns of OCPs in the profile might be affected by the usage and physicochemical properties of the pesticides, in addition to the adjacent geographical environment. The health risk assessment indicated that most OCPs had little impact on human health according to the acceptable risk level for carcinogens (10-6) recommended by the US EPA. However, carcinogenic effects caused by heptachlor, Aldrin, HCB, and α-HCH might occur in drinking water. The risk of negative impacts caused by OCPs is much higher for children than for adults.

  16. Spatio-Temporal Pattern and Socio-Economic Factors of Bacillary Dysentery at County Level in Sichuan Province, China

    PubMed Central

    Ma, Yue; Zhang, Tao; Liu, Lei; Lv, Qiang; Yin, Fei

    2015-01-01

    Bacillary dysentery (BD) remains a big public health problem in China. Effective spatio-temporal monitoring of BD incidence is important for successful implementation of control and prevention measures. This study aimed to examine the spatio-temporal pattern of BD and analyze socio-economic factors that may affect BD incidence in Sichuan province, China. Firstly, we used space-time scan statistic to detect the high risk spatio-temporal clusters in each year. Then, bivariate spatial correlation and Bayesian spatio-temporal model were utilized to examine the associations between the socio-economic factors and BD incidence. Spatio-temporal clusters of BD were mainly located in the northern-southern belt of the midwest area of Sichuan province. The proportion of primary industry, the proportion of rural population and the rates of BD incidence show statistically significant positive correlation. The proportion of secondary industry, proportion of tertiary Industry, number of beds in hospitals per thousand persons, medical and technical personnel per thousand persons, per capital GDP and the rate of BD incidence show statistically significant negative correlation. The best fitting spatio-temporal model showed that medical and technical personnel per thousand persons and per capital GDP were significantly negative related to the risk of BD. PMID:26469274

  17. Search for uranium in western United States

    USGS Publications Warehouse

    McKelvey, Vincent Ellis

    1953-01-01

    The search for uranium in the United States is one of the most intensive ever made for any metal during our history. The number of prospectors and miners involved is difficult to estimate but some measure of the size of the effort is indicated by the fact that about 500 geologists are employed by government and industry in the work--more than the total number of geologists engaged in the study of all other minerals together except oil. The largest part of the effort has been concentrated in the western states. No single deposit of major importance by world standards has been discovered but the search has led to the discovery of important minable deposits of carnotite and related minerals on the Colorado Plateau; of large, low grade deposits of uranium in phosphates in the northwestern states and in lignites in the Dakotas, Wyoming, Idaho and New Mexico; and of many new and some promising occurrences of uranium in carnotite-like deposits and in vein deposits. Despite the fact that a large number of the districts considered favorable for the occurrence of uranium have already been examined, the outlook for future discoveries is bright, particularly for uranium in vein and in carnotite-like deposits in the Rocky Mountain States.

  18. Two novel Fusarium species that cause canker disease of Sichuan pepper (Zanthoxylum bungeanum Maxim.) in northern China form a novel clade with F. torreyae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canker disease of Sichuan pepper (Zanthoxylum bungeanum) has caused a decline in the production of this economically important spice in northern China over the past twenty-five years. To identify the etiological agent, 38 fungal strains were isolated from symptomatic tissues from trees in five provi...

  19. Emerging Yr26-virulent races of Puccinia striiformis f. sp. tritici are threatening the wheat production in the Sichuan Basin, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici , is one of the most destructive diseases of wheat in the world. The Sichuan Basin is one of the most important regions of wheat production and stripe rust epidemics in China. Stripe rust resistance gene Yr26 (the same gene as Yr24) has bee...

  20. Assessing Soil Erosion Rates on Manually-tilled Hillslopes in the Sichuan Hilly Basin Using 137Cs and 210Pbex Radionuclides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopeland. But quantitative assessment of the erosion rate is difficult due to the manually-tilled small patches of lands, sophistic structure of land use, and steep hil...

  1. Case 3. "Jiang Tao v. Chengdu Branch, People's People's Bank of China": Opinion by the People's Court in Wuhou District, Chengdu, Sichuan Province

    ERIC Educational Resources Information Center

    Chinese Education and Society, 2006

    2006-01-01

    This article presents the decision of the People's Court in Wuhou District, Chengdu, Sichuan Province on the Jiang Tao v. Chengdu Branch, People's People's Bank of China case. Jiang Tao, the plaintiff, claimed that the defendant Chengdu Branch placed an announcement in the "Chengdu Business Daily" to "recruit tellers for Chengdu Branch" on…

  2. Characteristics and origins of carbonaceous aerosol in the Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Xie, Shaodong; Luo, Bin; Zhai, Chongzhi

    2014-09-01

    The Sichuan Basin is a low visibility area in southwest China, where the hilly and basin topography, plus humid and stagnant weather, lead to unique pollution patterns. To identify the characteristics and sources of carbonaceous aerosols, one-year record of 24-h PM2.5 samples were analyzed for organic carbon (OC) and elemental carbon (EC) content following the thermal/optical transmission protocol at three cities (Chengdu (CD), Neijiang (NJ), and Chongqing (CQ)) in the region during May 2012 to April 2013. The annual average concentrations were 19.0 ± 13.3 μg OC m-3 and 4.6 ± 2.6 μg EC m-3 in CD, 18.3 ± 8.4 μg OC m-3 and 4.1 ± 1.8 μg EC m-3 in NJ, and 15.2 ± 8.4 μg OC m-3 and 4.0 ± 1.6 μg EC m-3 in CQ, respectively. Organic matter (1.6OC) plus EC contributed about 40% of PM2.5 mass and displayed weak regional uniformity. Relatively high ratios of OC to EC were observed in the region with 4.3 for CD, 4.6 for NJ, and 3.8 for CQ, respectively. OC and EC pollution in the region exhibited interesting season-dependent characteristics with the lowest concentrations and OC/EC ratios in summer, but higher levels in other seasons. Higher OC/EC ratios in spring and autumn resulted from biomass burning, and in winter were from the enhanced secondary organic aerosol formation under favorable conditions. The exceptionally high OC and EC levels in May and October, mostly notable in CD, resulted from the burning of agricultural residues during harvest period. The high K+ concentrations and the high Kexcess/EC ratios implied the persistent influence of biomass burning throughout the year. Using a novel technique combing the EC tracer method and potassium mass balance in the aerosols, a K/EC ratio of 1.22 was used to retrieve the OC from biomass burning and the estimated contributions were 30.8%, 28.3%, and 21.9% in CD, NJ, and CQ, respectively, while secondary OC contributions to OC were 26.7%, 24.6%, and 25.7% in CD, NJ, and CQ, respectively.

  3. Summit geomorphology of western Pacific guyots

    NASA Astrophysics Data System (ADS)

    Van Waasbergen, Robert J.; Winterer, Edward L.

    Bathymetric and seismic reflection data for 21 guyots in the Japanese, Wake and Mid Pacific Mountains seamount groups show that many guyots bear thick shallow-water limestone deposits that represent nearly undeformed Cretaceous rudist-reef-bounded carbonate platforms. Three types of guyot summits are distinguished: those with more than 200 m of shallow-water limestone, sufficient to bury the underlying volcanic relief, follow the same basic morphologic patterns as their coral/algal-dominated modern counterparts. Surface morphology is controlled by the original reef/platform configuration, modified by subaerial erosion and by long-term deformation of the sedimentary deposits and the underlying volcanic edifice. These seamounts range in age from Barremian to Aptian, with Barremian or Aptian to late Albian limestone deposits. Guyots with thin limestone deposits represent reef-bearing volcanic islands at various stages of fringing-reef and barrier-reef development. These edifices and their overlying limestone deposits are of Albian age. Reef growth on these was suddenly halted when regional emergence led to cessation of shallow-water-limestone accumulation on all guyots in the western Pacific, probably during the latest Albian. The karstic surfaces were resubmerged by middle Turonian time and, in latitudes south of about 20°N, blanketed by pelagic ooze. Guyots without reef deposits appear to be products of post-Albian volcanism and erosion at sea level. Among the three types of summit-configurations a range of stages of development of Cretaceous carbonate-platforms can be observed. The exposure of the guyot summits indicated by the occurence of karstic relief of 100-200 m on many of the limestone caps suggests that the sea floor of the western Pacific was raised several hundred meters. The age and platform thickness-relationships among the different types of guyots suggests that this uplift occurred at late Albian time.

  4. Hesperian age for western Medusae Fossae Formation, Mars.

    PubMed

    Zimbelman, James R; Scheidt, Stephen P

    2012-06-29

    The Medusae Fossae Formation (MFF) on Mars is an intensely eroded deposit north of the cratered highlands. It is widely thought that MFF materials were emplaced through ignimbrite eruptions. Recent geologic mapping of western MFF identified outliers of MFF materials well beyond the previously mapped western extent for the deposit, including outliers close to Gale crater. We report counts of impact craters on the MFF units that have implications for our understanding of the general history of MFF and the uppermost layered materials on the Gale crater mound. PMID:22628559

  5. Geochemical characteristics of the Triassic Tethys-turbidites in northwestern Sichuan, China: Implications for provenance and interpretation of the tectonic setting

    NASA Astrophysics Data System (ADS)

    Gu, X. X.

    1994-11-01

    The Triassic Tethys graywacke-slate turbidites in the northwestern Sichuan, China have been analysed for major and trace elements and petrographically studied. Compared to Phanerozoic turbidites, the turbidites in this study are quartz-intermediate (average 55%) in composition and are characterized geochemically by their moderate Fe 2O ∗3 + MgO (9.28 ± 2.84%), TiO 2 (0.72 ± 0.17%) contents and Al 2O 3/SiO 2 (0.25 ± 0.10) ratios; moderate abundances of ferromagnesian trace elements ( Co = 15 ± 8 ppm, Cr = 113 ± 72 ppm, Ni = 14 + 9 ppm, Sc = 12 ± 4 ppm, etc.); and moderate contents of incompatible elements, such as Th (11 ± 3 ppm), U (3 ± 0.7 ppm), Zr (170 ± 64 ppm), Hf (4 ± 1 ppm) and total REEs (159 ± 33 ppm). In general, the slates show systematically higher Fe 2O ∗3 + MgO, Sc, Co and Eu/Eu∗, but lower solLa/Sc and Th/Sc than the associated graywackes, suggesting that various provenance components may separate into different grain-size fractions during sedimentary sorting processes, that is, the more mafic materials tended to incorporate into the sedimentary record for the clay-size fraction. Framework modes and geochemical data indicate that the turbidites were mainly derived from a recycled orogenic provenance characterized chiefly by sedimentary-metasedimentary rocks and granite-gneisses, similar to the upper continental crust, but with a variable admixture of continental island arc volcanic components. Flysch deposition took place in a back arc basin situated between an active continental margin (the Kunlun-Qinling fold belt) and a continental island arc (the Yidun island arc). Weathering conditions in the source area significantly influenced the composition and distribution of elements in the sediments. With the elapse of time during sedimentation, the degree of chemical weathering in the provenance became intense while the tectonic activity decreased gradually.

  6. The World Revolution of Westernization.

    ERIC Educational Resources Information Center

    Von Laue, Theodore H.

    1987-01-01

    Discusses the history of westernization from a global perspective. Analyzes the reasons for perceived Western "superiority," how these reasons contributed to the buildup of western power, and its attractiveness to non-Western cultures. Indicates the necessity for a trans-national, culturally non-specific view of history to meet this age of global…

  7. Postconflict Conciliation within One-Male Breeding Units in Sichuan Snub-Nosed Monkeys in the Qinling Mountains, China.

    PubMed

    Zhao, Hai-Tao; Li, Jia-Xuan; Wang, Xiao-Wei; Zhang, Jian; Wang, Cheng-Liang; Qi, Xiao-Guang; Guo, Song-Tao; Li, Bao-Guo

    2015-01-01

    This study analyzed conflict and postconflict (PC) conciliation between males and females within one-male breeding units in Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China. The PC matched-control and time rule methods were used to collect and analyze data recorded from September 2013 to June 2014. The conciliatory tendency among individuals following conflict was 82.07%, and affiliation occurred within a few minutes after the conflict, which was not significantly different between mating and nonmating seasons. The PC conciliation scenarios were different from those reported from captivity. Lumbar hold and grooming were the most common expressions in reconciliation. In addition, bystander affiliation was uniquely found, which may be associated with the more terrestrial locomotion of R. roxellana, compared with other colobines. PMID:26575480

  8. New characteristics of intensity assessment of Sichuan Lushan "4.20" M s7.0 earthquake

    NASA Astrophysics Data System (ADS)

    Sun, Baitao; Yan, Peilei; Chen, Xiangzhao

    2014-08-01

    The post-earthquake rapid accurate assessment of macro influence of seismic ground motion is of significance for earthquake emergency relief, post-earthquake reconstruction and scientific research. The seismic intensity distribution map released by the Lushan earthquake field team of the China Earthquake Administration (CEA) five days after the strong earthquake ( M7.0) occurred in Lushan County of Sichuan Ya'an City at 8:02 on April 20, 2013 provides a scientific basis for emergency relief, economic loss assessment and post-earthquake reconstruction. In this paper, the means for blind estimation of macroscopic intensity, field estimation of macro intensity, and review of intensity, as well as corresponding problems are discussed in detail, and the intensity distribution characteristics of the Lushan "4.20" M7.0 earthquake and its influential factors are analyzed, providing a reference for future seismic intensity assessments.

  9. Rings dominate western Gulf

    NASA Astrophysics Data System (ADS)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  10. Western coal marketing days

    SciTech Connect

    Dahle, H.

    1983-01-01

    Fifteen papers were presented covering the following: the outlook for Powder River Basin Coals; markets for medium-range Western coals; outlook for domestic coal sales; Canada - the reliable coal supplier; coal requirements and procurement policies; coal procurement at Nevada Power Co; Nebraska Public Power District coal fired power plants - specifications and projections; NSP and its fuel needs; coal procurement at Grand River Dam Authority; Son of OPEC: Western Fuels and its coal contracting procedures; an update of the coal supply and demand situation of China Light and Power Co. Ltd; maximum rate guidelines - deja vu or the real thing.; Western coal shippers concerns; domestic and export movements; 1984-eleven years later. Most of the papers are in the form of transcripts.

  11. Molecular Characterization and Seroprevalence in Pigs of SC0806, a Cat Que Virus Isolated from Mosquitoes in Sichuan Province, China

    PubMed Central

    Zhang, Jiake; Wang, Jinglin; Wang, Lihua; Fu, Shihong; Li, Minghua; Zhao, Guoyan; Zhu, Wuyang

    2015-01-01

    Abstract The Simbu serogroup currently consists of a highly diverse group of related arboviruses that infect both humans and economically important livestock species. Cat Que virus (CQV), a Simbu serogroup virus of the genus Orthobunyavirus (family Bunyaviridae), was first isolated in 2004 from mosquitoes during surveillance of arbovirus activity in acute pediatric encephalitis in northern Vietnam. We report here the complete genome sequence of SC0806 isolated from mosquitoes (Culex tritaeniorhynchus) in Sichuan Province, China. Consistent with the genomic organization of Simbu serogroup viruses, the SC0806 genome comprises three RNA segments—a large (L) segment (6928 nucleotides) that encodes the 2261-amino-acid RNA-dependent RNA polymerase, a medium (M) segment (4481 nucleotides) that encodes the 1433-amino-acid polyprotein, and a small (S) segment (984 nucleotides) that encodes a 234-amino-acid nucleocapsid protein and a 95-amino-acid nonstructural protein. The respective lengths of the 5′-untranslated region (UTR) and 3′-UTR of L, M, and S are 56 and 86, 43 and 136, and 44 and 238 nucleotides. Sequence (nucleotide and deduced amino acid) comparison and phylogenetic analysis revealed that SC0806 was closely related to the reported Vietnam isolate CQV. This is the first time that CQV has been isolated in Sichuan Province, China. Anti-SC0806 immunoglobulin M (IgM) and IgG antibodies were found in pigs reared locally, indicating that CQV has formed a natural cycle in the local area. Surveillance of the distribution and pathogenicity of SC0806 should be strengthened. PMID:26186514

  12. CRF07_BC Strain Dominates the HIV-1 Epidemic in Injection Drug Users in Liangshan Prefecture of Sichuan, China.

    PubMed

    Li, Lin; Wei, Daying; Hsu, Wan-Ling; Li, Tianyi; Gui, Tao; Wood, Charles; Liu, Yongjian; Li, Hanping; Bao, Zuoyi; Liu, Siyang; Wang, Xiaolin; Li, Jingyun

    2015-05-01

    The Liangshan prefecture in Sichuan province is an area in China severely affected by the HIV epidemic, with intravenous drug use (IDU) as the main risk factor. No reports on HIV subtypes prevalent in IDUs in Liangshan prefecture could be found. In this study, we have characterized the genotypes of HIV-1 in the IDU population in Liangshan prefecture and further determined the phylogenetic relationship of the CRF07_BC strains to HIV-1 sequences from the other regions of China, including Xinjiang and Yunnan provinces, to explore the pattern and possible diffusion pathway of HIV-1 in these regions. HIV-1-seropositive drug-naive IDUs identified in Liangshan prefecture, Sichuan province were enrolled in 2009. Full-length gag and pol genes were amplified by reverse transcription and nested PCR and then sequenced. All of the sequences were subtyped. Phylogenetic trees were constructed using the neighbor-joining and maximum likelihood methods. Divergence times were estimated using a Bayesian molecular clock approach. CRF07_BC was found to be the predominant strain in IDUs in Liangshan prefecture (95.5%). The CRF07_BC strains from Liangshan prefecture were found to be intermixed with those from Yunnan province in phylogenetic trees. The CRF07_BC sequences from Xinjiang province can be grouped into several clusters, suggesting that the expansion of the CRF07_BC epidemic in Xinjiang province was the result of a local epidemic driven by multiple independent introductions in the late 1990s. Only low-level drug-resistant viruses were found in the IDU population. CRF07_BC strains from Liangshan prefecture were more similar to those from Yunnan province than those from Xinjiang province. This finding will contribute to our understanding of the distribution, the evolution, and the potential source of CRF07_BC founder strains, and will also provide useful information for the development of strategies to prevent transmission. PMID:25560398

  13. CRF07_BC Strain Dominates the HIV-1 Epidemic in Injection Drug Users in Liangshan Prefecture of Sichuan, China

    PubMed Central

    Li, Lin; Wei, Daying; Hsu, Wan-Ling; Li, Tianyi; Gui, Tao; Wood, Charles; Liu, Yongjian; Li, Hanping; Bao, Zuoyi; Liu, Siyang; Wang, Xiaolin

    2015-01-01

    Abstract The Liangshan prefecture in Sichuan province is an area in China severely affected by the HIV epidemic, with intravenous drug use (IDU) as the main risk factor. No reports on HIV subtypes prevalent in IDUs in Liangshan prefecture could be found. In this study, we have characterized the genotypes of HIV-1 in the IDU population in Liangshan prefecture and further determined the phylogenetic relationship of the CRF07_BC strains to HIV-1 sequences from the other regions of China, including Xinjiang and Yunnan provinces, to explore the pattern and possible diffusion pathway of HIV-1 in these regions. HIV-1-seropositive drug-naive IDUs identified in Liangshan prefecture, Sichuan province were enrolled in 2009. Full-length gag and pol genes were amplified by reverse transcription and nested PCR and then sequenced. All of the sequences were subtyped. Phylogenetic trees were constructed using the neighbor-joining and maximum likelihood methods. Divergence times were estimated using a Bayesian molecular clock approach. CRF07_BC was found to be the predominant strain in IDUs in Liangshan prefecture (95.5%). The CRF07_BC strains from Liangshan prefecture were found to be intermixed with those from Yunnan province in phylogenetic trees. The CRF07_BC sequences from Xinjiang province can be grouped into several clusters, suggesting that the expansion of the CRF07_BC epidemic in Xinjiang province was the result of a local epidemic driven by multiple independent introductions in the late 1990s. Only low-level drug-resistant viruses were found in the IDU population. CRF07_BC strains from Liangshan prefecture were more similar to those from Yunnan province than those from Xinjiang province. This finding will contribute to our understanding of the distribution, the evolution, and the potential source of CRF07_BC founder strains, and will also provide useful information for the development of strategies to prevent transmission. PMID:25560398

  14. [Near infrared spectrum analysis and meaning of the soil in 512 earthquake surface rupture zone in Pingtong, Sichuan].

    PubMed

    Yi, Ze-bang; Cao, Jian-jin; Luo, Song-ying; Wang, Zheng-yang; Liao, Yi-peng

    2014-08-01

    Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Ping- tong town,Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite; talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region. By analyzing and comparing it was revealed that part of mineral compositions of the soil are in accordance with the characteristics of the rock mineral compositions below the rupture zone, indicating that part of the minerals of the soil's evolution is closely related to the rock compositions in this area; and the compositions of the clay mineral in the rupture zone is similar to the Ma Lan loess in the north of China, so it is presumed that the clay minerals in these two kinds of soil have the same genetic type. The characteristic of the mineral composition of the soil is in accordance with evolution characteristics of the rocks which is bellow the rupture zone, also it was demonstrated that the results of soil minerals near-infrared analysis can effectively analyze the mineral particles in the soil and indicate the pedogenic environment. Therefore, the result shows the feasibility of adopting modern near-infrared spectrum for rapid analysis of mineral particles of the soil and research of geology. Meanwhile, the results can be the foundation of this region's soil mineral analysis, and also provide new ideas and methods for the future research of soil minerals and the earthquake rupture zone. PMID:25508716

  15. [Near infrared spectrum analysis and meaning of the soil in 512 earthquake surface rupture zone in Pingtong, Sichuan].

    PubMed

    Yi, Ze-bang; Cao, Jian-jin; Luo, Song-ying; Wang, Zheng-yang; Liao, Yi-peng

    2014-08-01

    Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Ping- tong town,Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite; talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region. By analyzing and comparing it was revealed that part of mineral compositions of the soil are in accordance with the characteristics of the rock mineral compositions below the rupture zone, indicating that part of the minerals of the soil's evolution is closely related to the rock compositions in this area; and the compositions of the clay mineral in the rupture zone is similar to the Ma Lan loess in the north of China, so it is presumed that the clay minerals in these two kinds of soil have the same genetic type. The characteristic of the mineral composition of the soil is in accordance with evolution characteristics of the rocks which is bellow the rupture zone, also it was demonstrated that the results of soil minerals near-infrared analysis can effectively analyze the mineral particles in the soil and indicate the pedogenic environment. Therefore, the result shows the feasibility of adopting modern near-infrared spectrum for rapid analysis of mineral particles of the soil and research of geology. Meanwhile, the results can be the foundation of this region's soil mineral analysis, and also provide new ideas and methods for the future research of soil minerals and the earthquake rupture zone. PMID:25474937

  16. Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Jia, Dong; Yin, Hongwei; Liu, Mancang; Xie, Wuren; Wei, Guoqi; Li, Yongxiang

    2016-02-01

    The organic-rich lower Silurian shale of the Longmaxi Formation in the Sichuan Basin is the most important target for shale-gas exploration in China. Most Paleozoic rocks of the Sichuan Basin have experienced extraordinarily pervasive remagnetizations. To test a hypothesized connection between hydrocarbon generation and remagnetization and contribute to shale-gas exploration in the region, we undertook an integrated magnetic, geochemical, and petrographic study of 160 specimens from the shale. The results suggest that the shale contains a reliable remanent magnetization (Dec = 41.4°, Inc = 40.8°, and α95 = 6.8°). The magnetization predates tilting, and the paleopole plots close to the Late Triassic segment of the south China apparent polar wander path. The rock magnetic data and scanning electron microscope (SEM) observations confirm that framboidal magnetites carry the bulk of the magnetization, which suggest a Late Triassic chemical remanent magnetization in the shale. 87Sr/86Sr and magnetic analyses indicate that the amount of magnetite was unaffected by fluid alterations around the veins but is strongly covariant with the amount of total organic matter. Moreover, SEM observations reveal possible evidence of the replacement of pyrite framboids by magnetite, probably in the presence of organic acids. These analyses, therefore, suggest that the remagnetization was caused by organic maturation rather than orogenic fluids and that the maturation occurred in the Late Triassic. This timing of organic maturation has been validated by independent modeling studies and provides important constraints on the complex thermal history of the Longmaxi Shale as well as contributing to shale-gas exploration efforts.

  17. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    This viewgraph presentation reviews the work of the Western Aeronautical Test Range (WATR). NASA's Western Aeronautical Test Range is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). Maps show the general location of the WATR area that is used for aeronautical testing and evaluation. The products, services and facilities of WATR are discussed,

  18. Energy options and strategies for Western europe.

    PubMed

    Häfele, W; Sassin, W

    1978-04-14

    Western Europe, now largely dependent on oil imports, has to prepare for strong competition for oil and energy imports in general before the year 2000. The more unlikely it is for Western Europe to secure from outside rich supplies of coal or uranium at readily acceptable economic and political conditions, the more serious this competition becomes. Even exceptionally low projections of economic growth and optimistic assumptions about energy conservation urgently call for vigorous and simultaneous development of indigenous coal and nuclear sources, including the breeder. Long-term contracts for the possession and deployment of foreign oil, gas, and coal deposits are mandatory and should be negotiated in view of the possible aggravation of north-south confrontation. PMID:17818793