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Sample records for lake hovsgol nw

  1. Sedimentary Simulation for the Late Quaternary Sediments of Lake Hovsgol in Northern Mongolia: Reconstruction of Sedimentary Processes, Lake-Level Fluctuations, and Burial History

    NASA Astrophysics Data System (ADS)

    Cheong, D.; Cha, J.

    2012-12-01

    Lake Hovsgol is a tectonic lake in Baikal Rift System, located in northern Mongolia and 200 km away from southwestern Lake Baikal. In this study, SEDPAK computer simulation program is used to reconstruct the sedimentary process, lake-level and burial history. A khub012 line across the south central part in Lake Hovsgol and KDP-01, HDP-04 and HDP-06 core data drilled in nearby sites have been used for simulation modeling. Sedimentary sequences in the seismic section are divided into six sedimentary units. Input parameters of sediment supply, subsidence rate, and lake-level change for the sedimentary simulation are estimated for each sedimentary unit. As a result of sedimentary simulation, the various sedimentary processes, lake-level change, burial history, which were seriously affected from initial basin surfaces, are reconstructed for each sedimentary unit. They are main components of paleoenvironmental settings. The results are correlated with eustatic sea-level change, marine oxygen isotope record, and diatom content in Lake Baikal sediments, and they match well each other. It reflects the Hovsgol Lake sediments archive well the record of global climate change.

  2. Tectonics of the baikal rift deduced from volcanism and sedimentation: a review oriented to the Baikal and Hovsgol lake systems.

    PubMed

    Ivanov, Alexei V; Demonterova, Elena I

    2009-01-01

    As known from inland sedimentary records, boreholes, and geophysical data, the initiation of the Baikal rift basins began as early as the Eocene. Dating of volcanic rocks on the rift shoulders indicates that volcanism started later, in the Early Miocene or probably in the Late Oligocene. Prominent tectonic uplift took place at about 20 Ma, but information (from both sediments and volcanics) on the initial stage of the rifting is scarce and incomplete. A comprehensive record of sedimentation derived from two stacked boreholes drilled at the submerged Akademichesky ridge indicates that the deep freshwater Lake Baikal existed for at least 8.4 Ma, while the exact formation of the lake in its roughly present-day shape and volume is unknown. Four important events of tectonic/environmental changes at about approximately 7, approximately 5, approximately 2.5, and approximately 0.1 Ma are seen in that record. The first event probably corresponds to a stage of rift propagation from the historical center towards the wings of the rift system. Rifting in the Hovsgol area was initiated at about this time. The event of ~5 Ma is a likely candidate for the boundary between slow and fast stages of rifting. It is reflected in a drastic change of sedimentation rate due to isolation of the Akademichesky ridge from the central and northern Lake Baikal basins. The youngest event of 0.1 Ma is reflected by the (87)0Sr/ (86)Sr ratio increase in Lake Baikal waters and probably related to an increasing rate of mountain growth (and hence erosion) resulting from glacial rebounding. The latter is responsible for the reorganization of the outflow pattern with the termination of the paleo-Manzurka outlet and the formation of the Angara outlet. The event of approximately 2.5 Ma is reflected in the decrease of the (87)Sr/(86)Sr and Na/Al ratios in Lake Baikal waters. We suggest that it is associated with a decrease of the dust load due to a reorganization of the atmospheric circulations in Mainland

  3. Paleoclimatic record of the late Quaternary from a gravity core sediment of Lake Hovsgol in northern Mongolia

    NASA Astrophysics Data System (ADS)

    Cheong, D.; Kim, B.

    2007-12-01

    Gravity core sediment (HS 7) from Lake Hovsgol(Mongolia) is divided into three sedimentary units on the basis of sediments texture, water contents, occurrence of fossils and sediment color. Unit 1(27¢¦128§¯) is generally massive and is crudely stratified. Ostracods are well preserved over the all interval of Unit1, but diatoms are not well preserved. At Unit2(9¢¦27§¯), mud content is slightly low and lamination is well developed. It is dark greenish gray in the upper part, and dark greenish gray is alternating with light brownish gray in the lower part. Diatom contents increase towards the top and ostracods fragments disappear at the top of Unit 2. Unit3(0¢¦9§¯) is laminated mud in olive gray color. Diatom contents are high but ostracods are not observed in this unit. According to 14C age dating results, we assumed that Unit1 is Pleistocene sediment, Unit2 is sediment of a transitional stage and Unit 3 is Holocene sediment. Chemical composition of trace elements from ostracods show variations through Unit1, especially showing a distinct change at 95¢¦100§¯ interval. It matches to the distribution of ostracod at this interval. Contents of ostracod decrease at the interval and contents of Cytherissa lacustris decrease, but Limnocythere inopinata increase. It was interpreted that warm air was supplied to Lake Hovsgol after LGM(Last Glacial Maximum), causing ice melting. Consequently the bottom environment of Lake Hovsgol experienced some changes as the lake level increased little bit. At the top of Unit 1 appear a lots of pyrite which are arranged in line, and diatoms occure but ostracods are not observed toward the top of Unit 2, and lamination is developed in Unit 2. It means the bottom environment of Lake Hovsgol changed to anoxic condition. At that time, plenty of water was supplied into the lake, resulting in water stratification and cutting off oxygen supply to the bottom of Lake Hovsgol. It made the lake level rise higher, so that the bottom

  4. Paleoclimatic investigations during the late Quaternary using gravity core sediments of Lake Hovsgol in Mongolia

    NASA Astrophysics Data System (ADS)

    Cheong, Daekyo; Shin, Seungwon; Park, Yong-Hee; Nam, Seung Il

    2010-05-01

    The Lake Hovsgol is located in northeast Eurasia which is a tectonic lake formed by rifting, and its thick bottom sediments record climatic change of the past. The lake is a suitable site to study a rapid Quaternary climate change. This study includes analysis of smear slides, particle size analysis, data of spectrophotometer and magnetic susceptibility, trace element analysis using XRF core scanner for HS-3, 5 gravity core sediments from the middle southern Lake Hovsgol. HS-3 core sediments were measured for TOC, and HS-5 core was scrutinized for species analysis of ostracods. HS-3 core was obtained at 160 m water depth, and is divided into three sedimentary units. Unit A of HS-3 is characterized by distinct lamination, high sand contents considerably decreasing towards the upper part, and the ostracods are rarely discovered at the upper part of Unit A. Unit B is characterized by weakly lamination, and some ostracods are observed in the lower part, but diatoms are observed in the upper part of Unit B. Also grain size is getting smaller toward the upper part. Unit C consists of fine diatomaceous ooze and contains abundant diatoms. Overall organic contents are high, and lamination with black-colored organic layer is observed in the lower part of Unit C. HS-5 core was obtained at 210 m water depth and is divided into two sedimentary units with faint boundary. Unit A of HS-5 is characterized by lamination and contains abundant diatoms and ostracods. At Unit B, grain size is getting smaller toward the upper part, and occurrence change of ostracods is observed in the upper part. Framboidal pyrite were formed during the diagenesis. Four species of ostracods are observed in the core sediments, i.e. Cytherissa lacustris, Limnocythere inopinate dominate in the lower part, and Candona lepnevae, Leucocythere sp dominates in the upper part. Carbon age dating results show that sediment unit B of HS-5 and unit C of HS-3 containing rare ostracods are similar in age. The reason of

  5. Changes of clay mineral assemblages in Lake Hovsgol (Mongolia) in the course of their transportation and sedimentation

    NASA Astrophysics Data System (ADS)

    Zhdanova, A.; Solotchina, E.; Krivonogov, S.

    2009-04-01

    As known, clay minerals of lake sediments sensitively indicate climatic and environmental changes. Composition of clay mineral assemblages depends on petrography and weathering pattern of parental rocks in lake catchments. Lake Hovsgol, the second large basin in the Baikal Rift Zone, differs from the first one by extremely small drainage area: its ratio to the lake surface is 1.8 (compare with 17 of Lake Baikal). This peculiarity of lake Hovsgol defines the amount of clay minerals deposited in bottom sediments and the value of their transformation in the course of transportation We studied a number of short sediment cores (up to 1.75 m long) obtained from different parts of the lake in the framework of the Hovsgol Drilling Project, 2001-2007. Regularities of modern clay minerals transportation were studied in 80 samples from river mouths and piedmont slopes around the lake. Their mineral composition was determined by X-ray powder diffraction and IR-spectroscopy. For X-ray, we prepared the oriented mounts by transferring the suspension of bulk sample in distilled water onto a glass slide. Slides, dried at room temperature, then were solvated for about 24 hours with ethylene-glycol vapor in an evacuated desiccator. Measurements were conducted on an automated powder diffractometer with CuKα radiation, graphite monochromator. The comparative analysis of clay minerals and their crystallochemical parameters were performed by the original method of modeling X-ray diffraction profiles, based on the calculation of the interference function of the one-dimensional disordered crystals with finite thickness and using a specially developed optimization procedure. Quantitative estimations of the composition of minerals such as quartz, plagioclase, carbonate were made by IR-spectroscopy. Samples were prepared using the KBr pellet method. It was established that the mineral association in bottom sediments includes illite, smectite, chlorite, chlorite-smectite, muscovite, kaolinite

  6. Monitoring of Permafrost in the Hovsgol Mountain Region, Mongolia

    NASA Astrophysics Data System (ADS)

    Sharkhuu, A.; Natsagdorj, S.; Etzelmuller, B.; Heggem, E. S.; Nelson, F. E.; Shiklomanov, N.; Goulden, C.

    2005-12-01

    - facing ones. Intensive degradation of permafrost is also caused by human activities associated with land use. For example, initial results of short term (3 years) monitoring of permafrost in the northeastern shore valleys of Lake Hovsgol show that the depth of the active layer varies from 1.4 m in Borsog valley in the south to 4.8 m in Turag valley in the north, apparently in relation to livestock grazing pressure. We have also begun monitor active frost heaving on pingos in the eastern shore valleys and active thaw settlement (thermokarst) in the Darhad depression. In general, the permafrost in the Hovsgol Mountain Region is degrading more intensively than in the Khentei and Khangai Mountain Regions. The recent degradation of permafrost under the influence of climate warming and human activities leads to some changes in natural and ecological balance. In particular, our observations have indicated deforestation in the taiga zone and desertification in the steppe zone of the Hovsgol region.

  7. Age and growth comparisons of Hovsgol grayling (Thymallus nigrescens Dorogostaisky, 1923), Baikal grayling (T. baicalensis Dybowski, 1874), and lenok (Brachymystax lenok Pallas, 1773) in lentic and lotic habitats of Northern Mongolia

    USGS Publications Warehouse

    Tsogtsaikhan, Pureviin; Mendsaikhan, Budiin; Jargalmaa, Ganzorigiin; Ganzorig, Batsaikhanii; Weidel, Brian C.; Filosa, Christopher; Free, Christopher; Young, Talia; Jensen, Olaf P.

    2017-01-01

    Despite concern over the conservation status of many Mongolian salmonids and the importance of their ecological role in Mongolia's aquatic ecosystems, little is known about their basic biology. Hovsgol grayling (Thymallus nigrescens) is endemic to Lake Hovsgol, Mongolia and listed as endangered on the Mongolian Red List. Baikal grayling (T. baicalensis) and lenok (Brachymystax lenok) are found in lakes and rivers throughout the Selenge drainage. A detailed study of the age and growth of these three salmonids was conducted based on 1,682 samples collected from July 2006 to July 2013 in Lake Hovsgol, its outlet the Eg River, and one of the Eg's largest tributaries, the Uur River. Our results suggest that Hovsgol grayling in particular can reach a much older maximum age (17 years in our samples) than previously believed based on aging from scales. Female Hovsgol grayling were heavier at a given length than their male counterparts. Lenok had a greater average length-at-age in Lake Hovsgol compared to the rivers and greater weight-at-length in the warmer Uur River than in the Eg; female lenok from the rivers had a greater average length-at-age than their male counterparts. This study provides critical new information for the management and conservation of these threatened salmonid species in Mongolia.

  8. Influence of geomorphic setting on sedimentation of two adjacent alpine lakes, Triglav Lakes Valley (Julian Alps, NW Slovenia)

    NASA Astrophysics Data System (ADS)

    Smuc, Andrej; Skabene, Dragomir; Muri, Gregor; Vreča, Polona; Jaćimović, Radojko; Čermelj, Branko; Turšič, Janja

    2013-04-01

    The Triglav Lakes Valley is elongated, 7km long depression, located high (at places over 2000 m.a.s.l.) in the central part of the Julian Alps (NW Slovenia). It hosts 6 small isolated lakes that formed due to the combination of Neogene tectonic and Pleistocene glaciation. The study is focused on the 5th and 6th Triglav Valley Lakes that characterize lower part of the valley. The lakes are located so close to each other that they are even connected in times of high water. Thus, they share the same bedrock geology, are subjected to the same climatic forcing and share similar vegetation communities. Despite their proximity, the lakes differ in their hydrologic and geomorphic setting. The lakes have no permanent surface tributaries; however 5th is fed periodically, at times of high water level, by the Močivec spring, while additional water flows from the swamp area near its northern shore. An underground spring on the eastern side of 5th represents the lake's only permanent freshwater inflow, while drainage takes place to the west via a small ponor. 6th has only one weak underground spring on the eastern side of the lake. Water levels may fluctuate between 2 and 3 m. Additionally, the lakes have different configuration of lakes shores; the northern shores of the 5th lake are low-angle soil and debris covered plateau, while southern shores of the 5th lake and shores of the 6th lake are represented by heavily karstified carbonate base rock and covered partly by trees. The detailed sedimentary analysis of the lakes record showed some similarities, but also some significant differences. Sediments of both lakes are represented by fine-grained turbidity current deposits that are transported from lake shores during snow melt or storms. The grain-size and sedimentary rates of the lakes are however markedly different. The 5th lake has coarser grained sediments, with mean ranging from 46 to 60 µm and records higher sedimentation rates of ~0,57 cm/year, compared to the 6th lake

  9. Rock magnetic properties of sediments from Lake Sanabria and its catchment (NW Spain): paleoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Larrasoaña, J. C.; Borruel, V.; Gómez-Paccard, M.; Rico, M.; Valero-Garces, B.; Moreno-Caballud, A.; Soto, R.

    2013-12-01

    Lake Sanabria is located in the NW Spanish mountains at 1000 m a.s.l., and constitutes the largest lake of glacial origin in the Iberian Peninsula. Here we present an environmental magnetic study of a Late Pleistocene-Holocene sediment core from Lake Sanabria and from different lithologies that crop out in its catchment, which includes Paleozoic plutonic, metamorphic and vulcanosedimentary rocks, and Quaternary deposits of glacial origin. This study was designed to complement sedimentologic and geochemical studies aimed at unraveling the climatic evolution of the NW Iberian Peninsula during the last deglaciation. Our results indicate that magnetite and pyrrhotite dominate the magnetic assemblage of both the sediments from the lower half of the studied sequence (25.6 - 13 cal kyr BP) deposited in a proglacial environment, and the Paleozoic rocks that make up most of the catchment of the lake. The occurrence of these minerals both in the catchment rocks and in the lake sediments indicates that sedimentation was then driven by the erosion of a glacial flour, which suffered minimal chemical transformation in response to a rapid and short routing to the lake. Sediments from the upper half of the studied sequence, accumulated after 12.4 cal kyr BP in a fluviolacustrine environment, contain magnetite and greigite. This points to a prominent role of post-depositional reductive dissolution, driven by a sharp increase in the accumulation of organic matter into the lake and the creation of anoxic conditions in the sediments, in shaping the magnetic assemblage of Holocene sediments. Pyrrhotite is stable under reducing conditions as opposed to magnetite, which is unstable. We therefore interpret that previous pedogenic processes occurred in the then deglaciated catchment of the lake were responsible for the oxidation of pyrrhotite and authigenic formation of magnetite, which survived subsequent reductive diagenesis given its initial larger concentrations. This interpretation is

  10. The endemic mollusks reveal history of the long-lived Pliocene Lake Slavonia in NW Croatia

    NASA Astrophysics Data System (ADS)

    Mandic, Oleg; Kurečić, Tomislav; Neubauer, Thomas A.; Harzhauser, Mathias

    2015-04-01

    The present investigation deals with the fossil mollusk record of the long-lived Pliocene Lake Slavonia settled in the southern Pannonian Basin. The samples originate from Vukomeričke gorice, a low hill-range situated north of the Kupa River in the area between the towns of Zagreb, Sisak and Karlovac in NW Croatia. Representing the SW margin of the Lake Slavonia the freshwater deposits alternate there with the alluvial series, providing altogether about 400-m-thick, Pliocene continental succession, known in literature by informal name Paludina beds (acc. to a junior synonym of Viviparus). The endemic fauna of the Lake Slavonia became particularly well-known in the late 19th century after Melchior Neumayr demonstrated that the gradual evolutionary change of the mollusk phenotypes toward more complex morphology represents a function of adaptation to environmental change in the paleolake. Even Charles Darwin commented that result as by far the best case which I have ever met with, showing the direct influence of the conditions of life on the organization. The deposition in the Lake Slavonia (~4.5 to ~1.8 Ma) coincides with the Pliocene Climate Optimum (PCO), but captures also the transition into the Pleistocene climate marked by the initial Ice Age pulse at 2.59 Ma. The increase of polar temperatures resulted during PCO in a significant melting of the ice caps leading to a global sea level rise tentatively getting up to 25 m higher than today. Coincidence of the climate and geodynamic settings in southeastern Europe provided conditions supporting extended settlement of lacustrine environments including Lake Slavonia, Lake Kosovo, Lake Transylvania and Lake Dacia, all characterized by explosive adaptive radiations of viviparid snails. In particular, the latter adaptive radiations resulted in the regional phylostratigraphy of Lake Slavonia Viviparus species enabling excellent stratigraphic control for the investigated deposits. Hence, based on this evidence, the

  11. Earthquake Records of North Anatolian Fault from Sapanca Lake Sediments, NW Anatolia

    NASA Astrophysics Data System (ADS)

    Yalamaz, Burak; Cagatay, Namık; Acar, Dursun; Demirbag, Emin; Gungor, Emin; Gungor, Nurdan; Gulen, Levent

    2014-05-01

    We determined earthquake records in sediment cores of Sapanca Lake which is a pull-apart basin located along the North Anatolian Fault zone in NW Anatolia. The lake has a maximum depth of 55 m, and a surface area of 46.8 km2, measuring 16 km in E-W and 5 km in N-S directions. A systematic study of the sedimentological, physical and geochemical properties of three water-sediment interface cores, up to 75.7 cm long, located along depth transects ranging from 43 to 51.5 m water depths. The cores were analyzed using Geotek Multi Sensor Core Logger (MSCL) for physical properties, laser particle size analyzer for granulometry, TOC Analyzer for Total Organic Content (TOC) and Total Inorganic Carbon (TIC) analysis, Itrax-XRF Core Scanner for elemental analysis and digital X-RAY Radiography. The geochronology was determined using AMS radiocarbon and radionuclide methods. The Sapanca Lake earthquake records are characterized by mass flow units consisting of grey or dark grey coarse to fine sand and silty mud with sharp basal and transional upper boundaries. The units commonly show normal size grading with their basal parts showing high density, and high magnetic susceptibility and enrichment in one or more elements, such as Si, Ca, Tİ, K, Rb, Zr and Fe, indicative of coarse detrial input. Based on radionuclide and radiocarbon analyses the mass flow units are correlated with 1999 İzmit and Düzce earthquakes (Mw=7.4 and 7.2, respectively) , 1967 Mudurnu earthquake (Mw= 6,8), and 1957 Abant (Mw= 7.1) earthquake. Keywords: Sapanca Lake, North Anatolian Fault, Earthquake, Grain size, Itrax-XRF, MSCL

  12. Effect of depositional regimes on polycyclic aromatic hydrocarbons in Lake Bled (NW Slovenia) sediments.

    PubMed

    Muri, Gregor; Wakeham, Stuart G

    2009-09-01

    Polycyclic aromatic hydrocarbons (PAH) were measured in sediment cores from two contrasting depositional regimes in urban Lake Bled (NW Slovenia). The concentration of PAH in surface sediments, mostly derived from combustion, was higher in Zaka Bay where bottom waters are permanently oxic, than in the western basin where bottom waters oscillate between suboxic and anoxic (1930 vs. 1150ngPAHg(-1) dry weight (dw), respectively). This pattern is the reverse of what might be expected if PAH were to preferentially degrade under oxic conditions. Two PAH from non-combustion sources, perylene and retene, are also present in the sediments. Post-depositional diagenetic formation of perylene appeared to occur only in anoxic sediments. Differences in the source of sedimentary organic matter (autochthonous vs. allochthonous) is probably not a major factor in perylene formation, since the two locations have markedly different sources of organic matter but quite similar concentrations of perylene in deeper sediments, ranging from 250 to 350ngg(-1)dw. Thus, redox conditions may play a role in perylene generation. On the other hand, redox conditions in general can not be the only or even the major factor affecting the fate of sedimentary PAH since uniform compositions and depth distributions for pyrolytic PAH were observed in both cores, in spite of the two locations differ in redox, mixing and biota conditions. Thus, degradative loss of PAH is unlikely in Lake Bled sediments.

  13. The stability of Cladoceran communities in 32 subarctic NW Finnish Lapland lakes since pre-industrial era

    NASA Astrophysics Data System (ADS)

    Leppänen, J. J.; Siitonen, S.; Weckström, J.

    2016-12-01

    Historical and ongoing environmental changes affecting aquatic ecosystems may easily go unnoticed. These background shifts complicate the interpretation of observations and hamper restoration planning. Zooplankton is regarded as a good indicator of environmental change of which cladocerans (water fleas) are one of the most used paleobioindicators. To assess whether cladoceran assemblages had remained unchanged in lakes with low human impact and to produce background information of possible environmental changes during the last few centuries, we compared pre-industrial and modern cladoceran assemblages in 32 lakes in NW Finnish Lapland. The study area ranges from low altitude forest catchments to high altitude tundra and includes a notable ecoclimatic gradient. A data set of measured environmental variables was used to determine their explanatory power on cladoceran assemblages. Cladoceran communities have remained relatively stable, but change in the species level was clearer with a significant proportional increase in Eubosmina spp. (Wilcoxon signed rank test z = 2.75 p = 0.006). Loss on ignition (LOI) was the strongest environmental variable to explain the variation in the cladoceran community. Since LOI is strongly correlated to allochthonous and autochthonous primary production, the differences in cladoceran communities between lakes and also the increased abundance of Eubosmina spp. may eventually be related to the trophic status of the lakes. Temperature and precipitation has increased in NW Lapland during the past few decades, but factors related to climate change cannot convincingly be attributed to increased abundance of Eubosmina spp. because the studied lakes respond differently to climatic factors. Our results are in relatively good agreement with previous studies conducted in northern hemisphere. Also, the increased abundance of planktonic cladoceran taxa since pre-industrial period has been noted before. The top-bottom approach is based on two

  14. Waterborne and on-land electrical surveys to suggest the geological evolution of a glacial lake in NW Italy

    NASA Astrophysics Data System (ADS)

    Colombero, Chiara; Comina, Cesare; Gianotti, Franco; Sambuelli, Luigi

    2014-06-01

    Geophysical surveys on and around the Candia Lake, located NE of Turin (NW Italy), in the internal depression of the Ivrea Morainic Amphitheater (IMA) right frontal sector, are reported in this paper. The surveys were intended to obtain a geophysical characterization of the lakebed, to investigate the interconnection paths between surface water and groundwater and to be used as a first general survey for suggesting the geological processes which lead to the actual morphology. An extensive waterborne continuous vertical electrical sounding (CVES) survey consisting of 15 profiles, with a total length of about 19 km of acquisition, was carried out on the lake surface. The processing of the acquired profiles with a laterally constrained inversion (LCI) approach lead to the reconstruction of the lakebed sediment distribution, down to 10 m depth. Self potential (SP) data recorded on the lake surface have also been analyzed. Moreover, to verify the areal distribution of the deposits, three electrical resistivity tomographies (ERTs) were carried out on land near the northern and southern shores of the lake. The combination of the geophysical survey results with hydrogeological information and geological observations and interpretations allowed the characterization of the submerged deposits, the probable identification of the main areas of groundwater recharge and the preliminary reconstruction of the lake genesis.

  15. Using discontinuous wave-cut terraces to reconstruct the history of former glacial lake levels: the example of Lake Ojibway in NW Quebec (Canada)

    NASA Astrophysics Data System (ADS)

    Daubois, V.; Roy, M.; Veillette, J. J.

    2012-12-01

    The decay of the southern Laurentide ice sheet maring during the last deglaciation led to the development of Lake Agassiz and Lake Ojibway that covered large areas in the western prairies and in NE Ontario-NW Quebec, respectively. The history of glacial lakes is commonly based on the study of strandlines that generally consist of sandy beaches (and near-shore facies) or boulder ridges. However, the use of this approach is limited in the main Ojibway basin where the surficial geology consists predominantly of thick accumulation of fine-grained glaciolacustrine deposits that mask most deglacial landforms and the underlying bedrock. Nonetheless, earlier mapping programs in this flat-lying clay plain revealed a complex sequence of discontinuous small-scale cliffs that are made of Ojibway rhythmites. These terrace-like features range in size from 4 to 7 m in height and can generally be followed for 10 to 100's of meters, and sometimes for several kms. These small-scale features are interpreted to represent raised shorelines that were cut into glaciolacustrine sediments by lakeshore erosional processes (i.e., wave action). These so-called wave-cut benches (WCBs) occur at elevations ranging mostly from 3 to 30 m above the present level of Lake Abitibi (267 m), one of the lowest landmarks in the area. Here we evaluate the feasibility of using this type of shorelines to constrain the evolution of Ojibway lake levels in NW Quebec. For this purpose, a series of wave-cut terraces (WCBs) were measured along two north-south transects of about 40 km in length in the Lake Abitibi region. The absolute elevation of more than 70 WCBs was determined with a Digital Video Plotter software package using 1:15K air-photos, coupled with precise measurements (x,y,z coordinates) of control points, which were measured with a high-precision Global Navigation Satellite System tied up to known geodesic survey markers. Preliminary results suggest that Lake Ojibway experienced at least three

  16. Evolution of Chaka Salt Lake in NW China in response to climatic change during the Latest Pleistocene Holocene

    NASA Astrophysics Data System (ADS)

    Xingqi, Liu; Dong, Hailiang; Rech, Jason A.; Matsumoto, Ryo; Bo, Yang; Yongbo, Wang

    2008-04-01

    The Late Pleistocene and Holocene hydrologic balance of Chaka Salt Lake in the eastern Qaidam Basin of NW China was studied based on the analysis of lithostratigraphy, mineralogy, total organic carbon, and total nitrogen from a 9.0-m long sediment core. An age-depth model for the lake sediments is based on eight accelerator mass spectrometry (AMS) 14C measurements of organic matter and a 1700-year radiocarbon reservoir correction. The Pitzer model was used to calculate the sequence of minerals precipitated as a function of salinity assuming that the initial lake water was recharged from adjacent rivers and springs. Lake salinity values were derived from a good match between the calculated and observed mineral sequences. Our multi-proxy based hydrologic reconstruction of Chaka Lake indicates that it was a clastic-dominated, freshwater lake between 17.2 and 11.4 cal ka BP, which may have resulted from the input of glacial water into the lake at that time. During the Lateglacial and Holocene, a warm climatic regime predominated between 13.9 and 12.7 cal ka BP and then a cold climatic regime prevailed between 12.7 and 11.4 cal ka BP. These warm and cold periods correlate with the Bølling-Allerød and Younger Dryas events in the region. Beginning at 11.4 cal ka BP, a saline or hypersaline lake developed, which may have resulted from increased summer insolation and temperatures. These conditions persisted throughout the Holocene. Modeling indicates that lake salinity fluctuated between 66 and 223 ppt from 11.4 to 7.2 cal ka BP and then increased to 223-322 ppt between 7.2 and 6.0 cal ka BP, when most regions of China recorded high moisture availability (i.e. the so-called "mid-Holocene Climatic Optimum"). Lake salinity decreased to 66-223 ppt during a short time period between 6.0 and 5.3 cal ka BP, possibly caused by reduced evaporation. Subsequently, salinity values rapidly increased to 223-322 ppt between 5.3 and 5.2 cal ka BP and a hypersaline lake with a salinity

  17. Seismic influence on the last 1500-year infill history of Lake Sapanca (North Anatolian Fault, NW Turkey)

    NASA Astrophysics Data System (ADS)

    Leroy, Suzanne A. G.; Schwab, Markus J.; Costa, Pedro J. M.

    2010-04-01

    Lake Sapanca is located on the North Anatolian Fault Zone in NW Turkey. It occupies a pull-apart basin at the junction between the İzmit-Sapanca fault segment, the Sakarya segment and the westernmost end of the Mudurnu Valley fault. Multiproxy analyses (lithology, loss-on-ignition, geochemistry, magnetic susceptibility and palynology) of a 586-cm-long sediment core taken in the centre of the lake revealed a complex history of at least five mass-movement events. The radiocarbon chronology suggests that the sediment sequence spans approximately the last 1500 years. The bottom metre of the sequence, before c. AD 580, is a gley soil resulting from a large sublacustrine landslide, whose origin is a collapse of the floodplain between the lake and River Sakarya. Sedimentation related to this eastern floodplain decreases progressively until c. AD 910. Sedimentological and palynological indicators from sediments younger than c. AD 910 document four major episodes of mass-movement originating most likely from the southern slopes of the lake. The landslide and the following four mass-movement events are suggested to be linked to earthquakes.

  18. Evidence for former Glacial Lakes in the High Peaks and Rossendale Plateau areas, NW England.

    NASA Astrophysics Data System (ADS)

    Delaney, Cathy; Crofts, Richard; Rhodes, Ed; Jones, Christopher

    2010-05-01

    The identification of former ice-dammed lakes associated with Quaternary ice sheets is important for two reasons. Firstly, these lakes can contain varved sediments which can be used to establish a chronology related to ice margin position, and also provide a high-resolution (sub-annual) record of meltwater discharge from the ice sheet, which in turn can be related to climate. Secondly such lakes are commonly associated with sporadic outburst floods, which are an important geomorphic agent and can affect ice dynamics. This paper examines the evidence for the occurrence of ice-dammed lakes, ponded between the uplands of the South Pennines and the lowland, late Devensian, British Ice Sheet around Manchester, and explores the possibility of establishing a varve chronology for this area. The position of lakes has been reconstructed from a combination of borehole records of laminated silts and clays and associated sands, and morphological evidence, including shorelines and meltwater channels. Both lateral and pro-glacial ice-dammed lakes existed at Glacial Maximum in this area. Two former lakes, the High Peaks Lake, a pro-glacial ice-dammed lake, and Lake Rawtenstall, a lateral ice-dammed lake, are examined in more detail. Borehole records and one new borehole from the High Peaks Lake indicate varved sediments deposited in an ice-advance lake are preserved underneath glacial tills, but that post-glacial lake sediments are absent, indicating an ice-retreat lake of relatively short duration, and probable rapid reworking of exposed lakes sediments. Former Lake Rawtenstall contains much longer sequences of rhythmically laminated sediments, and may have existed for a considerable period of time (>1,000 years) across the Glacial Maximum. A number of shorelines were identified, indicating that lake level dropped as the ice margin receded and the lake surface area expanded. In its latter stages the lake is likely to have partly or fully drained periodically, causing outburst

  19. Holocene lake level fluctuations of a small alpine lake in the Qilian Mountains, NW China: a comparison of chironomid, ostracod, pollen and geochemistry data.

    NASA Astrophysics Data System (ADS)

    Mischke, S.; Herzschuh, U.

    2003-04-01

    A core of 14 m length was drilled in a small alpine lake in the Qilian Mountains, NW China. The lake Luanhaizi has a drainage area of about 30 km2 and is situated at an altitude of 3200 m which represents the altitude of the present regional upper timberline. Due to the small size of the open-basin lake (surface area about 1 km2) and the sharply outlined catchment area the lake is regarded as a very sensitively and rapidly responding ecosystem. Analyses of ostracod shells, head capsules of larval chironomids and pollen and spores were conducted and the organic and carbonate content (LOI), element concentrations and magnetic susceptibility of core samples determined. Ostracod taxa mainly comprise Candona candida, C. neglecta, C. rawsoni, Cyclocypris ovum, Cypridopsis vidua, Fabaeformiscandona caudata, F. danielopoli, F. hyalina, Herpetocypris chevreuxi, Heterocypris salina, Ilyocypris cf. bradyi, I. echinata, I. lacustris and Limnocythere inopinata. They may be used to distinguish periods of low lake levels corresponding to a dense cover of aquatic plants at the lake bottom from stages of higher lake levels and a corresponding decrease in macrophytes at the core site. Chironomid taxa belonging to Chironomus, Cladopelma, Glyptotendipes, Micropsectra, Paratanytarsus, Polypedilum, Psectrocladius and Tanytarsus further provide information on variations in benthic oxygen availability and lake level fluctuations. Several units of the core show high abundances of pollen and spores of higher aquatic and wetland plants and fungi (Cyperaceae, Hippuris, Myriophyllum and Glomus) indicating low lake levels. In contrast, algae such as Botryococcus, Pediastrum and Tetraedron were regarded to reflect higher water levels. Typha angustifolia-type, Typha latifolia, Alisma and Potamogeton were recorded in low abundances as well. The organic content of core samples averages 6 % displaying four alternating stages of distinct minima and maxima. Lowest values of about 1 % occur at the core

  20. Reconstructing Climate Change Since The Late Glacial At Amsterdamøya, NW Svalbard (80°N), Based On Lake Sediments From Lake Hakluytvatnet

    NASA Astrophysics Data System (ADS)

    Gjerde, Marthe; Bakke, Jostein; D'Andrea, William J.; Balascio, Nicholas L.; Hormes, Anne; Bradley, Raymond S.

    2015-04-01

    Records of past climatic changes are sparse and poorly resolved in the Arctic due to obvious reasons such as lack of dateable organic material and logistical challenges. Here, we present a new time series from the island of Amsterdamøya, NW Svalbard (80°N), based on lake sediments from Lake Hakluytvatnet. Located at the northernmost branch of the North Atlantic Current, this high-Arctic site is ideally placed to infer changes in past atmospheric and oceanic circulation patterns recorded as changes in precipitation and temperature. Our novel data set provides a climatic reconstruction based on multi-proxy analyses on lake sediments from a non-glacial lake. We have combined one long piston core with a shorter gravity core to capture the entire sediment infill from the bottom of the basin to the most recently accumulated sediments on top. A robust chronology has been established for the cores through 28 AMS radiocarbon (14C) ages in combination with one lead (210Pb) profile of the most recent sediments, and this gives an unprecedented age control for a lake at this latitude as well as a precise sediment accumulation rate. The Hakluytvatnet cores are analysed for physical sediment properties as well as newer scanning instruments (e.g. XRF scanning, Scanning Electron Microscope, SEM, analyses) in order to produce a high-resolution reconstruction of the climate development for the study site. A separate alkenone study will produce a high-resolution temperature curve for the area. Soil samples from the surrounding catchment have also been subject to geochemical analyses in order to distinguish between the relative influences of different sediment sources on sediment accumulation in the lake. Geomorphological mapping has been carried out to combine interpretation of the catchment development with the lake sediment record interpretation. Numerical analyses (e.g. Principal Component Analysis, PCA) are applied on the results from the lake sediment and catchment samples in

  1. DC resistivity and seismic refraction survey across the SE margin of Lake Ngami, NW Botswana

    NASA Astrophysics Data System (ADS)

    Shemang, Elisha; Molwalefhe, Loago

    2009-09-01

    Seismic refraction survey and DC resistivity measurements were made across the margin of the Lake Ngami. The structure and stratigraphy at the lake were determined. High resolution aeromagnetic data showed a prominent anomaly coinciding with the Kunyere Fault. Estimated depths to magnetic sources are increasing towards the lake. Two velocity layers were mapped. The top layer (500 m/s) is thin outside the lake and thicker inside the lake. The underlying layer (3125 m/s) has undeterminable thickness. Resistivity sounding results inside the lake showed that the low velocity layer has four sub-units: dry hard clays; diatomaceous earth; soft clays interlayered with silts; and wet whitish clays interlayered with silts. Normal faults were mapped along the profile with a total displacement up to 50 m. The results of the study indicate that the formation of the Lake Ngami basin was structurally controlled and probably initiated by the tectonics of the Okavango Rift Zone.

  2. Polychlorinated biphenyls and organochlorine pesticides in atmospheric air of the Northern Hovsgol region in 2008-2013

    NASA Astrophysics Data System (ADS)

    Mamontova, E. A.; Tarasova, E. N.; Goreglyad, A. V.; Tkachenko, L. L.; Mamontov, A. A.; Kuzmin, M. I.

    2015-10-01

    Results of the study of organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB) from the listing of the Stockholm Convention in atmospheric air of the Northern Hovsgol region at the base of the "Khankh" stationary, Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, in 2008-2013 in the absence of clear sources of these compounds are considered. Quantitative and qualitative changes in the concentration of PCB and OCP in atmospheric air of the Northern Hovsgol region in 2008-2013 characterizing the influence of natural (annual temperature variations) and anthropogenic (atmospheric transportation from the territories of neighboring countries) are shown.

  3. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu

    2016-07-01

    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  4. New paleoreconstruction of transgressive stages in the northern part of Lake Ladoga, NW Russia.

    NASA Astrophysics Data System (ADS)

    Terekhov, Anton; Sapelko, Tatyana

    2016-04-01

    Lake Ladoga is one of the largest lakes in the world and the largest in Europe. The watershed of lake Ladoga covers the North-Western part of European Russia and the Eastern Finland. Lake basin is on the border between the Baltic shield and the East European Platform. The most consistent paleoreconstructions of Lake Ladoga history are based on bottom sediments of smaller lakes, which used to be a part of Ladoga in the past. The stages of Ladoga evolution are directly connected with the history of the Baltic Ice Lake (BIL) and of the Ancylus Lake. Water level of these lakes was significant higher than nowadays level. Lake Ladoga in its present limits used to be an Eastern gulf of BIL and Ancylus Lake. The preceding paleoreconstructions of Ladoga water level oscillations were undertaken by G. de Geer, J. Ailio, E. Hyyppä, K. Markov, D. Kvasov, D. Malakhovskiy, M. Ekman, G. Lak, N. Davydova, M. Saarnisto, D. Subetto and others. The new data on multivariate analysis of bottom sediments of lakes which used to belong to Ladoga, collected in the last few years, allows to create several maps of Ladoga transgressive stages in Late Glacial period and post-glacial time. A series of maps showing the extent of Ladoga transgression was created based on lake sediments multivariate analysis and a GIS-modeling using the digital elevation data with an accuracy of several meters and an open-source software (QGIS and SAGA). Due to post-glacial rebound of the lake watershed territory, GIS-modeling should comprise the extent of the glacioisostatic uplift, so the chart of a present-day uplift velocity for Fennoscandia of Ekman and Mäkinen was used. The new digital elevation models were calculated for several moments in the past, corresponding to the most probable dates of smaller lakes isolation from Lake Ladoga. Then, the basin of Ladoga was "filled" with water into GIS program to the levels sufficient for the smaller lakes to join and to split-off. The modern coastlines of Ladoga and

  5. Lake level changes in Hala Lake(NW China) based on ostracodassemblages during the LGM and Post-LGM

    NASA Astrophysics Data System (ADS)

    Yan, D.; Wuennemann, B.

    2012-12-01

    The Hala Lake, located in the Qilian Mountains, Qinghai Province, China, at 4078 m a.s.l. may archive in its sediments hydrological and climate changes during the Late Quaternary time, as it is close to the area impacted by the East-Asian Summer monsoon and westerly-driven air masses. Based on the sediment core H7, which was taken in the center of the lake at 65m water depth,ostracod assemblages and stable isotopes from ostracode shells were investigated in details. Three main species were found, which are common species in high altitude saline lakes of the Tibetan Plateau: Leucocythere sp.,Limnocythereinopinata and Eucypris sp.They started to occur in deeper part of H7,indicating an early onset of favorable living conditions during the LGM and post-LGM periods. Besides, algae occurred between 25 and 32m water depth. According to the unevenly distributed amount of ostracods and oxygen isotope data, our results indicate important lake level changes during the global LGM and Lateglacial. The lake experienced lowest levels of 25-50 m below the present water line. Ostracods disappeared with the onset of the early Holocene.A stepwise refilling started already at ca. 16 kyr BP and reached -25 m level during the Bølling/Allerød warm phase at ca. 13.5 kyr BP.Latest at ca.7.6 kyr BP, the lake reached a stable highstand similar to the present level until ca.6 kyr BPas . The subsequent lake development remains unclear due to strong mismatches of the data but may indicate a general trend to deteriorating conditions and lake level lowstands at ca. 5.0-4.2, 2.0 and at around 0.5 kyr BP.; Ostracods Distribution in H2 ; Ostracods plate in Hala lake

  6. Depth evolution of the Meirama pit lake, A Coruña, NW Spain

    NASA Astrophysics Data System (ADS)

    Delgado, Jordi; Juncosa-Rivera, Ricardo; Cereijo-Arango, José Luis; García-Morrondo, David; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja

    2016-04-01

    The Meirama pit lake is a water mass in the process of controlled flooding that, by the end of December 2015, can be described as a steadily stratified meromictic system. The deepest portion of the lake (monimolimnion) is isolated regarding the annual mixing dynamics (December/January) of the upper water body (mixolimnion), for which the depth of mixing is restricted to a water column of 35-40 m thick. Due to the contrasting flooding history (access of groundwater at the beginning and mixed access of stream/groundwater (being dominant the stream water) the deepest portion of the lake is separated from the upper, non-mixed layer by a marked chemocline. Strictly speaking, the monimolimnion of a meromictic lake extends to the waters located beneath the mixed lake layer. In the case of the Meirama Lake the monimolimnion is internally stratified and made of two major water bodies. From hereafter the deep and upper monimolimnion will be identified as bottom and middle sections of the lake while the mixolimnion is referred to as the surface layer. The general characteristics and evolution of the Meirama Lake have been reported elsewhere. In this work we focus on a summary description of the chemical evolution of the monimolimnion of the lake based on data gathered between 2009 and 2015 from the still on-going monitoring survey. The chemical evolution of the monimolimnion of the lake differs significantly from that of the mixolimnion. In general, surface water is sensible to seasonal fluctuations due to weather conditions, rainfall and biogeochemical processes. The middle and bottom sections are not sensible, in general, to this effects and their evolution obeys to a number of internal processes. In the case of temperature we observe a nearly constant gradient increase (0.001 °C/day) in the middle and deep lake waters up to the beginning of 2012, where it remains constant. The rise in temperature is likely due to the heat provided by groundwater seepage whose temperature

  7. Source identification and sedimentary record of polycyclic aromatic hydrocarbons in Lake Bled (NW Slovenia) using stable carbon isotopes.

    PubMed

    Petrišič, Marinka Gams; Muri, Gregor; Ogrinc, Nives

    2013-02-05

    A combination of molecular and stable isotope analyses was used to trace and identify the sources of polycyclic aromatic hydrocarbons (PAH) in sediments of Lake Bled (NW Slovenia). Sediment samples were taken from two locations with contrasting depositional regimes: Zaka Bay, with permanently oxic bottom and station D, where anoxic conditions prevail throughout the year. The concentrations of PAH in surface sediments at the two locations were comparable and higher than in previous studies, reaching 4230 and 4380 ng g(-1), respectively. It was found that retene (Re) and perylene (Per) are both mainly of natural origin in Zaka Bay while, at station D, the value of δ(13)C determined at a depth of 12-14 cm in the 1950s indicated that Re was of pyrolytic origin. The distribution of δ(13)C values of other individual PAH showed that PAH input to lake sediments was of pyrolytic origin, likely dominated by coal and later in 1950s also by wood burning. PAH from vehicular emissions could also contribute to the overall isotope signatures at the depth of 12-14 cm at station D and Zaka Bay corresponding to the period 1953-1961.

  8. Persistence time series analyses, complexity applied to natural hazards and the Quaternary lake history of the Lerma Valley, NW Argentina

    NASA Astrophysics Data System (ADS)

    Malamud, Bruce D.

    This dissertation explores the Quaternary history of a NW Argentina valley, persistence in synthetic self-affine time series, and complexity applied to natural hazards. Chapter one is an introduction. Chapter two examines the Lerma Valley in NW Argentina, today an externally drained basin which in the past was partially closed and contained a large fresh-water lake. Using geologic fieldwork laboratory work, and historical data analysis, we find that the lake was extant 1-50 ky during the period 0.78-0.1 Ma, had a surface area of 800-1300 kmsp2 and sedimentation rates of 1-10 m/ky. Modern denudation rates could supply enough sediment from the drainage to account for these rates, and the modern hydrologic regime could fill the lake with water in less than 500 years. Chapter three provides a framework to examine persistence techniques in self-affine time series. By using the Fourier spectral method, a white noise is appropriately filtered so that its power spectral density (S) depends upon frequency (f) according to S˜ fsp{-beta}. We examine fractional noises and walks with {-}3≤beta≤ 5 and Gaussian and log-normal distributions. The persistence analyses compared include autocorrelation, semivariogram, rescaled-range, Fourier power spectrum, extreme-value, and wavelet power spectrum. The last two are applied for the first time. In chapter four, self-organized critical (SOC) models are compared with actual events. The models have power-law noncumulative frequency-size distributions with exponent about 1.0, and the actual data have exponents 1.3-1.5 (forest-fires) and 2.3-3.3 (landslides). Actual forest fires are compared here for the first time with the forest-fire model; their robustness in one indicator of SOC behavior. Chapter five examines recurrence intervals of floods using power-law statistics applied to partial-duration series and the federally adopted log-Pearson type 3 (LP3) distribution applied to annual series. The great Mississippi River flood of 1993

  9. The role of clay minerals in the preservation of organic matter in sediments of qinghai lake, NW China

    USGS Publications Warehouse

    Yu, B.; Dong, H.; Jiang, H.; Lv, G.; Eberl, D.; Li, S.; Kim, J.

    2009-01-01

    The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our

  10. Climate and human impacts on the vegetation in NW Turkey: palynological insights from Lake Iznik since the Last Glacial

    NASA Astrophysics Data System (ADS)

    Miebach, Andrea; Niestrath, Phoebe; Roeser, Patricia A.; Litt, Thomas

    2015-04-01

    , the vegetation was also influenced by anthropogenic activities. During an early settlement phase near Lake Iznik, beginning ca. 8 ka cal BP (Roodenberg & Schier 2001), only minor changes in the pollen assemblage are registered. Still, evidence for human activity consolidates since the Early Bronze Age: cultivated trees, crops, and secondary human indicator species appeared, and forests got cleared. Subsequent fluctuations between extensive agricultural use and regeneration of the natural vegetation can be clearly correlated to the regional archaeological history. References: Roeser, P.A. (2014): Paleolimnology of Lake Iznik (NW Turkey) during the past ~ 31 ka cal BP. PhD thesis, University of Bonn, Germany. Roodenberg, J.J. & Schier, W. (2001): Radiocarbon determinations. In: Roodenberg, J.J. & Thissen, L.C. (eds.): The Ilıpınar Excavations II. PIHANS 93, Leiden: 257-278. Zohary, M. (1973): Geobotanical foundations of the Middle East. Gustav Fischer Verlag, Stuttgart.

  11. Toxic effects of mining effluents on fish gills in a subarctic lake system in NW Russia.

    PubMed

    Tkatcheva, Victoria; Hyvärinen, Heikki; Kukkonen, Jussi; Ryzhkov, Leonid P; Holopainen, Ismo J

    2004-03-01

    The mining company Karelian Pellet in northwestern Russia extracts iron ore and processes it locally into pellets. The production operations affect the environment in the form of air pollution and wastewater emissions to lakes downstream from the factory. The toxic effects of the mining effluents on gills of perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied. In lakes close to the factory, heavy metal concentrations in gills were not high, even though the metal content in sediment was elevated. In fish gills the relative proportion of phosphatidylcholine was elevated and cholesterol reduced, while the histological structure of the gills was changed. The number of mucus cells, as well as the sizes and the lengths of open areas in the chloride cells, had increased in spring and summer. The hypertrophy of chloride cells is possibly caused by the increased ambient concentrations of K+ and Li+. Changes in gill cholesterol and phospholipid proportions increase the fluidity of membranes and possibly strengthen their protective qualities, counterbalancing the adverse changes in chloride cell structure. The bioavailability and toxic effects of metals on fish are reduced by the hardness and high pH of water discharged by the mining plant.

  12. Parasitism of Odonata by Arrenurus (Acari: Hydrachnidia) larvae in the Lake Świdwie, nature reserve (NW Poland).

    PubMed

    Zawal, Andrzej; Buczyński, Paweł

    2013-12-01

    Larvae of a vast majority of water mite species are parasites of aquatic insects. Owing to this, they migrate to new localities, and are able to survive unfavourable environmental conditions. This also concerns species from subgenus Arrenurus s. str., parasites of dragonflies. The detailed analysis of this phenomenon, however, has only been possible in the last several years, since the key to the identification of larvae from genus Arrenurus Dug. was published. In 2010, the parasitism of Arrenurus s. str. larvae on dragonflies in the Lake Świdwie reserve (NW Poland) was analysed. Larvae of 9 species of water mites were recorded on 107 imagines of dragonflies from 8 species. The following were identified as hosts of water mites for the first time: Anax imperator, Libellula quadrimaculata, and Leucorrhinia caudalis. The highest prevalence occurred in the case of: Erythromma najas and Lestes dryas (100%), Coenagrion pulchellum (96.5%), and C. puella (80.0%). Coenagrion pulchellum was infested by 9 species of parasites, C. puella by 6, and Erythromma najas and Lestes dryas by three species. The highest number of host species occurred in the case of Arrenurus maculator (5); followed by A. cuspidator, A. batillifer cf., A. bicuspidator, and A. tetracyphus (3 each); A. papillator, A. tricuspidator, and A. bruzelii (2 each), and A. claviger (1). Differentiation of preferences of particular parasites towards various parts of the host body was observed, probably related to the coevolution of parasites and hosts, and competition between the host species. The body sizes of the parasites suggest that approximately 50% of body size growth of water mites from subgenus Arrenurus s. str. occurs at the stage of parasitic larva.

  13. Structural and stratigraphic features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Morris, K.; Weeks, W. F.; Wakabayashi, H.

    1994-01-01

    Changes in Earth Remote-Sensing Satellite (ERS) 1 C band synthetic aperture radar (SAR) backscatter intensity (sigma(exp 0)) from ice growing on shallow tundra lakes at three locations in NW Alaska are described. Ice core analysis shows that all lakes on the coast at Barrow the ice, whether floating or frozen to the bottom, includes an inclusion-free layer overlying a layer of ice with tubular bubbles oriented parallel to the direction of growth. The clear ice may also be overlain by a discontinuous layer of bubbly snow ice. Backscatter is low (-16 to -22 dB) at the time of initial ice formation, probably due to the specular nature of the upper and lower ice surfaces causing the radar pulse to be reflected away from the radar. As the ice thickens during the autumn, backscatter rises steadily. Once the ice freezes to the lake bottom, regardless of the presence of foward scattering tubular bubbles, low backscatter values of -17 to -18 dB are caused by absorption of the radar signal in the lake bed. For ice that remains afloat all winter the ice-water interface and the tubular bubbles combine, presumably via an incoherent double-bounce mechanism, to cause maximum backscatter values of the order of -6 to -7 dB. The sigma(exp 0) saturates at -6 to -7 dB before maximum ice thickness and tubular bubble content are attained. A simple ice growth model suggests that the layer of ice with tubular bubbles need be only a few centimeters thick midway through the growth season to cause maximum backscatter from floating ice. During the spring thaw a previously unreported backscatter reversal is observed on the floating and grounded portions of the coastal lakes but not on the lakes farther inland. This reversal may be related to the ice surface topography and wetness plus the effects of a longer, cooler melt period by the coast. Time series of backscatter variations from shallow tundra lakes are a record of (1) the development of tubular bubbles in the ice and, by association

  14. Structural and stratigraphic features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Morris, K.; Weeks, W. F.; Wakabayashi, H.

    1994-01-01

    Changes in Earth Remote-Sensing Satellite (ERS) 1 C band synthetic aperture radar (SAR) backscatter intensity (sigma(exp 0)) from ice growing on shallow tundra lakes at three locations in NW Alaska are described. Ice core analysis shows that all lakes on the coast at Barrow the ice, whether floating or frozen to the bottom, includes an inclusion-free layer overlying a layer of ice with tubular bubbles oriented parallel to the direction of growth. The clear ice may also be overlain by a discontinuous layer of bubbly snow ice. Backscatter is low (-16 to -22 dB) at the time of initial ice formation, probably due to the specular nature of the upper and lower ice surfaces causing the radar pulse to be reflected away from the radar. As the ice thickens during the autumn, backscatter rises steadily. Once the ice freezes to the lake bottom, regardless of the presence of foward scattering tubular bubbles, low backscatter values of -17 to -18 dB are caused by absorption of the radar signal in the lake bed. For ice that remains afloat all winter the ice-water interface and the tubular bubbles combine, presumably via an incoherent double-bounce mechanism, to cause maximum backscatter values of the order of -6 to -7 dB. The sigma(exp 0) saturates at -6 to -7 dB before maximum ice thickness and tubular bubble content are attained. A simple ice growth model suggests that the layer of ice with tubular bubbles need be only a few centimeters thick midway through the growth season to cause maximum backscatter from floating ice. During the spring thaw a previously unreported backscatter reversal is observed on the floating and grounded portions of the coastal lakes but not on the lakes farther inland. This reversal may be related to the ice surface topography and wetness plus the effects of a longer, cooler melt period by the coast. Time series of backscatter variations from shallow tundra lakes are a record of (1) the development of tubular bubbles in the ice and, by association

  15. The disappearing of the largest lake in the Middle East: Geochemical clues for human impact on Urmia salt lake NW Iran

    NASA Astrophysics Data System (ADS)

    Sharifi, O.; Haeri-Ardakani, O.; Pourmand, A.

    2012-12-01

    The water level in Lake Urmia, the third largest saline lake on earth and the largest continental lake in the Middle East, has dropped by more than 9 m over the last two decades, with no signs of improvement in recent years. Urmia is a hypersaline shallow lake (average salinity ~200 ‰) located in a closed continental drainage basin in northwestern Iran, and is surrounded by a variety of rock formations, ranging in age from Precambrian metamorphic complexes to Holocene mud deposits. Lake sediments are composed of two major components; chemical-biochemical and clastic fractions. Based on grain size analysis of samples from 24 push-cores, silt-size particles dominate the lake's sediments with clay-bearing materials mostly present near the center of the lake. Sand-size particles are dominant in the northwest, where felsic to intermediate plutonic and metamorphic rocks are located in the proximity of the lake. The water of the Urmia Lake can be classified as Na-K-Cl-Mg-SO4 brine. Based on chemical analysis of conservative lithogenic elements (e.g., Ti, Si, Al, Ca) as well as redox-sensitive elements (e.g., Fe, K, Rb, Sr) in the clastic fraction of the lake's sediment, elemental distributions are reflective of regional geology. The main sources of ions to the lake are evaporite formations with minor contribution from igneous rocks. Ion concentrations in the northern part of the lake are nearly constant throughout the year while south-southeastern parts of the lake show variable annual ion concentration due to major fresh water inflows. Chemical analysis of the surface sediment samples for heavy metals (Ni, Cr, V and Hg) indicate moderate to high degrees of contamination in the affected areas, where Hg is the most abundant heavy metal. The highest concentrations of Hg (Normalized Enrichment Factor =6) are observed in the middle part of the lake, where intensive dredging and construction activities have taken place. In contrast, the lowest concentrations of Hg in

  16. Chemical pollution in inland shallow lakes in the Mediterranean region (NW Spain): PAHs, insecticides and herbicides in water and sediments.

    PubMed

    Hijosa-Valsero, María; Bécares, Eloy; Fernández-Aláez, Camino; Fernández-Aláez, Margarita; Mayo, Rebeca; Jiménez, Juan José

    2016-02-15

    The possible effect of land uses and human-related geographic patterns (presence of roads and urban settlements) on chemical pollution was evaluated in the waters and sediments of fifty-three Mediterranean shallow lakes. The presence of fifty-nine pollutants (belonging to PAHs, insecticides and herbicides groups) was analysed in these lakes by GC-MS. The studied lakes had similar pollutant concentrations to other lakes worldwide. The distribution of the compounds between water and sediment compartments was strongly influenced by log K(ow) values (an average of 3.61 for compounds found in water and of 4.69 for compounds found in sediments). A multivariate analysis suggested that the concentration of PAHs in water could be related to agricultural activities and not related to local road traffic. When assessing nutrient levels in the lakes, it was observed that eutrophicated lakes [>300 μg L(-1) total phosphorus (TP)] appeared in areas affected by urban or industrial use (at least 2% urban use in a 1-km radius around the lake), whilst lakes with lower TP concentrations were placed in forest areas (60% of forest use in a 1-km radius); in addition, the aqueous concentrations of Σ(PAH) were lower in lakes with higher TP concentrations (>150 μg L(-1) TP), which could be related to the adsorption capacity of PAHs onto suspended matter which is present in mesotrophic and eutrophic lakes, thus being removed from the aqueous phase. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Tracking climate change in oligotrophic mountain lakes: Recent hydrology and productivity synergies in Lago de Sanabria (NW Iberian Peninsula).

    PubMed

    Jambrina-Enríquez, Margarita; Recio, Clemente; Vega, José Carlos; Valero-Garcés, Blas

    2017-07-15

    Mountain lakes are particularly sensitive to global change as their oligotrophic conditions may be rapidly altered after reaching an ecological threshold, due to increasing human impact and climate change. Sanabria Lake, the largest mountain lake in the Iberian Peninsula and with a recent history of increased human impact in its watershed, provides an opportunity to investigate recent trends in an oligotrophic, hydrologically-open mountain lake, and their relationship with climate, hydrological variability and human pressure. We conducted the first systematic and detailed survey of stable isotope compositions of Sanabria Lake and Tera River together with limnological analyses during 2009-2011. δ(18)Olakewater and δDlakewater seasonal fluctuations are strongly linked to river discharges, and follow the monthly mean isotopic composition of precipitation, which is controlled by NAO dynamics. δ(13)CPOM and δ(13)CDIC revealed higher contribution of allochthonous organic matter in winter and spring due to higher river inflow and lower primary productivity. Increased phytoplankton biomass in late summer correlated significantly with higher pH and Chl-a, and higher nutrient input and lower river inflow. However, the small δ(13)CPOM seasonal amplitude underlines the stability of the oligotrophic conditions and the isotopic variation in POM and DIC reflect small seasonal fluctuations mostly as a consequence of strong throughflow. The stability of hydrology and productivity patterns is consistent with Holocene and last millennium reconstructions of past limnological changes in Sanabria Lake. The results of this study indicate that trophic state in this hydrologically-open mountain lake is strongly controlled by climate variability, but recent changes in human-land uses have increased sediment delivery and nutrients supply to the lake and have to be considered for management policies. Monitoring surveys including isotope techniques provide snapshots of modern isotope

  18. Rapid and fundamental paleolimnological changes in Lake Iznik (NW Turkey) during the Holocene/Pleistocene transition: a multiproxy - multisite approach.

    NASA Astrophysics Data System (ADS)

    Gromig, R.; Viehberg, F. A.; Damcı, E.; Ülgen, U. B.; Assonov, S.; Franz, S. O.; Cagatay, M. N.; Litt, T.; Melles, M.; Wagner, B.; Staubwasser, M.

    2016-12-01

    The Marmara region is a key area to investigate the teleconnection and environmental changes of the Black Sea/Eastern Mediterranean Sea and northern hemisphere climate patterns. Lake Iznik, an oligohaline lake, is the largest lake in the Bosphorous region, which holds a continuous sediment archive. A hydro-acoustic survey screened the locations of three sediment cores (5 to 17 m) from previous field campaigns. The longest record reaches back almost to the Campanian Ignimbrite (39.3 cal kyr BP), which represents most likely the lowermost high amplitude reflector in hydro-acoustic profiles. The late Pleistocene ostracode fauna appears low in diversity and evolves abruptly to an abundant monospecific species assemblage of Limnocythere inopinata during the Younger Dryas after substantial alteration in the hydrocarbonate and alkalinity system of Lake Iznik. This distinct change in hydrochemistry is reflected in the appearence of different shell phenotypes and the occurence of a population with sexual reproduction (males/females). Independently, results from stable isotope analyses (δ18O and δ13C) on ostracode shells also suggest that Lake Iznik evolves from a freshwater system to a closed basin sensitive to temperature and precipitation changes.

  19. Cold active hydrolytic enzymes production by psychrotrophic Bacilli isolated from three sub-glacial lakes of NW Indian Himalayas.

    PubMed

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Kaushik, Rajeev; Saxena, Anil Kumar

    2016-03-01

    The diversity of culturable, cold-active enzymes producing Bacilli was investigated from three sub-glacial lakes of north western Indian Himalayas. Amplified ribosomal DNA restriction analysis (ARDRA) using three restriction enzymes Alu I, Msp I, and Hae III led to the clustering of 136 Bacilli into 26, 23, and 22 clusters at 75% similarity index from Chandratal Lake, Dashair Lake, and Pangong Lake, respectively. Phylogenetic analysis based on 16S rRNA gene sequencing led to the identification of 35 Bacilli that could be grouped in seven families viz.: Bacillaceae (48%), Staphylococcaceae (14%), Bacillales incertae sedis (13%), Planococcaceae (12%), Paenibacillaceae (9%), Sporolactobacillaceae (3%), and Carnobacteriaceae (1%), which included twelve different genera Bacillus, Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus, and Virgibacillus. Based on their optimal temperature for growth, 35 Bacilli were grouped as psychrophilic (11 strains), psychrotrophic (17 strains), or psychrotolerant (7 strains), respectively. The representative isolates from each cluster were screened for cold-active enzyme activities. Amylase, β-glucosidase, pectinase, and protease activities at 4 °C were detected in more than 80% of the strains while approximately 40, 31, 23, 14, 11, and 9% of strains possessed cellulase, xylanase, β-galactosidase, laccase, chitinase, and lipase activity, respectively. Among 35 Bacilli, Bacillus amyloliquefaciens, Bacillus marisflavi, Exiguobacterium indicum, Paenibacillus terrae, Pontibacillus sp., Sporosarcina globispora, and Sporosarcina psychrophila were efficient producers of different cold-active enzymes. These cold-adapted Bacilli could play an important role in industrial and agricultural processes.

  20. Shoreline change assessment using multi-temporal satellite images: a case study of Lake Sapanca, NW Turkey.

    PubMed

    Duru, Umit

    2017-08-01

    The research summarized here determines historical shoreline changes along Lake Sapanca by using Remote Sensing (RS) and Geographical Information Systems (GIS). Six multi-temporal satellite images of Landsat Multispectral Scanner (L1-5 MMS), Enhanced Thematic Mapper Plus (L7 ETM+), and Operational Land Imager Sensors (L8 OLI), covering the period between 17 June 1975 and 15 July 2016, were used to monitor shoreline positions and estimate change rates along the coastal zone. After pre-possessing routines, the Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI), and supervised classification techniques were utilized to extract six different shorelines. Digital Shoreline Analysis System (DSAS), a toolbox that enables transect-based computations of shoreline displacement, was used to compute historical shoreline change rates. The average rate of shoreline change for the entire cost was 2.7 m/year of progradation with an uncertainty of 0.2 m/year. While the great part of the lake shoreline remained stable, the study concluded that the easterly and westerly coasts and deltaic coasts are more vulnerable to shoreline displacements over the last four decades. The study also reveals that anthropogenic activities, more specifically over extraction of freshwater from the lake, cyclic variation in rainfall, and deposition of sediment transported by the surrounding creeks dominantly control spatiotemporal shoreline changes in the region. Monitoring shoreline changes using multi-temporal satellite images is a significant component for the coastal decision-making and management.

  1. Paleo-climate and paleo-environment reconstruction based on a high-resolution, multi-proxy Holocene lake record from Lake Urmia (NW Iran)

    NASA Astrophysics Data System (ADS)

    Haghipour, Negar; Eglinton, Timothy; McIntyre, Cameron; Darvishi Khatooni, Javad; Hunziker, Daniela; mohammadi, Ali

    2016-04-01

    Lake Urmia, in northwest Iran, is the largest saline lake in the Middle East with a surface area of ~ 5000km2. Historical documents indicate its existence since at least 2000 years BC, and palynological investigation of a 100 m-long core suggest it contains a sedimentary record spanning the last 200 ka. Despite this potential as an archive of paleo-climate and paleo-environmental information, to date there has been no molecular organic geochemical investigation or precise dating of these sediments. We present lake sediment core data on both geochemical proxies and sediment lipid biomarkers on two cores form different part of the Lake. Each core has 10m length and covers Holocene time scale. The age model based on calibrated radiocarbon dates shows variation of sedimentation rates between early and middle Holocene and a sudden increase in late Holocene. This is interpreted as a sudden event and mass movement. Downcore results on bulk measurements (TOC, δ13C and C/N) give evidence for a warmer and wetter climates between 0.5 and 3 kyr BP. Phytoplankton biomarkers were most abundant in this period, indicating high phytoplankton productivity. Further gradual shift to cooler and drier episodes occur between 3.5 and 7Kyr Bp, decrease in phytoplankton productivity indicating cooler climate and show terrestrial signal. The coolest and drier conditions occurred between 7-10.3 Kyr BP. This is in agreement with Carbon and Hydrogen isotopic composition of n-alkonic acids.

  2. Towards a quantitative climate reconstruction linking meteorological, limnological and sedimentological datasets: the Lake Sanabria (NW Spain) case.

    NASA Astrophysics Data System (ADS)

    Rico-Herrero, María. Teresa; Giralt, Santiago; Valero-Garcés, Blas L.; Vega, José Carlos

    2010-05-01

    It is well-known that lacustrine sediment records constitute one of the best environmental sensors to reconstruct climate variability. Nevertheless, our knowledge of how the climate signal (precipitation, temperature, wind stress) is transferred from the atmosphere to the lake water masses (through the limnological variables such as pH, nutrient inputs or water chemistry) and to the sediments is very poor. Besides there are few reliable and temporal long limnological and/or meteorological datasets. This lack also prevents the conversion of these qualitative climate reconstructions into quantitative ones. Lake Sanabria (Zamora) is located in the northwestern of the Iberian Peninsula (42°07'30' N, 06°43'00' W), at 1.000 m a.s.l. It is the largest glacial lake (368 ha, 51 m of water depth at the deepest point and 96 Hm3 of water volume) in the Iberian Peninsula. The main water and sediments input and output is the Tera River. Monthly limnological (secchi disk, water temperature profiles, conductivity, pH, dissolved oxygen), nutrients (nitrates, silicon, total phosphorous, reactive phosphorous, total chlorophyll and a-chlorophyll), hydrological (Tera river discharge) and meteorological (precipitation and air temperature from the Ribadelago meteorological station) datasets covering the period 1992 - 2005 were employed to explore the relationships between the atmosphere and the Lake Sanabria hydrological balance, and the limnological variables. X-Ray Fluorescence (XRF) core scanner data of two gravity cores (SAN04-3A and SAN07-1M) allowed us to characterize with high resolution the evolution of the chemical composition of the uppermost sedimentary infill. SAN07-1M was dated using gamma-spectrometry (210Pb) and a key bed corresponding to the dam failure of the Vega de Tera Reservoir located upstream occurred in 1959 AD. The relationships between the sedimentological and limnological datasets allowed us to characterize the transference of the climate signal from the

  3. Gravity anomaly at a Pleistocene lake bed in NW Alaska interpreted by analogy with Greenland's Lake Taserssauq and its floating ice tongue

    USGS Publications Warehouse

    Barnes, D.F.

    1987-01-01

    A possible example of a very deep glacial excavation is provided by a distinctive gravity low located at the front of a valley glacier that once flowed into glacial Lake Aniuk (formerly Lake Noatak) in the western Brooks Range. Geologic and geophysical data suggest that sediments or ice filling a glacially excavated valley are the most probable cause of the 30-50 mGal anomaly. Reasonable choices of geometric models and density contrasts indicate that the former excavation is now filled with a buried-ice thickness of 700 m or sediment thicknesses greater than 1 km. No direct evidence of efficient excavation was observed in Greenland, but efficient glacial erosion behind a floating polar ice tongue could explain the excavation that caused the Alaskan gravity anomaly. -from Author

  4. An INTIMATE Example: Into and out of the Younger Dryas at Lake Hämelsee, NW-Germany

    NASA Astrophysics Data System (ADS)

    de Bruijn, Renée; Engels, Stefan; Hoek, Wim Z.; Lane, Christine S.; Sachse, Dirk; Wagner-Cremer, Friederike

    2014-05-01

    Lake Hämelsee is a classical site with an excellent high-resolution record of Pleniglacial to Holocene climate and environment, contained in 18m of lacustrine sediments. At the centre of the lake, the Late Glacial interval consists of 2.7m of sapropelic and silty muds, that are mostly laminated (Merkt and Müller, QI 1999). In the framework of a summer school - 'An INTIMATE Example' - the lake was cored again, with the purpose of applying the latest techniques in palaeoclimatology and -ecology. Twenty international students and Early Stage Researchers (ESR's) from a wide range of backgrounds participated in lectures and field work and gained hands-on-experience with several proxies and techniques. Ongoing research by participants of the training school is focused on the timing and nature of the Allerød - Younger Dryas (YD) and YD - Preboreal transitions. Five short-term international exchange visits have provided opportunities for participants to learn and apply new techniques to the Hämelsee record, supervised by members of the INTIMATE network. A new age model will be constructed for the Late Glacial core section based on a combination of 14C-dates on macro-remains, varve chronology and tephrochronology. Tephrostratigraphic correlations will allow direct correlation of the record to both marine and ice core records from the North Atlantic region, as well as other European archives. Palaeoclimatic and -ecological research will include pollen-, chironomid-, LOI-, XRF-, lipid biomarker, stable isotope and GDGT-analysis. Temperature reconstructions will be made based on several of these proxies, providing a unique opportunity to compare independent reconstructions using material from a single record. Not only did the training school and subsequent research provide an excellent opportunity for ESR's to learn and work with international experts in the field - the collected data will also provide a high-resolution multi-proxy record of palaeoclimatology, -ecology and

  5. Geophysical, isotopic, and hydrogeochemical tools to identify potential impacts on coastal groundwater resources from Urmia hypersaline Lake, NW Iran.

    PubMed

    Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh; Kholghi, Majid

    2016-08-01

    Measurements of major ions, trace elements, water-stable isotopes, and geophysical soundings were made to examine the interaction between Urmia Aquifer (UA) and Urmia Lake (UL), northwest Iran. The poor correlation between sampling depth and Cl(-) concentrations indicated that the position of freshwater-saltwater interface is not uniformly distributed in the study area, and this was attributed to aquifer heterogeneities. The targeted coastal wells showed B/Cl and Br/Cl molar ratios in the range of 0.0022-2.43 and 0.00032-0.28, respectively. The base-exchange index (BEI) and saturation index (SI) calculations showed that the salinization process followed by cation-exchange reactions mainly controls changes in the chemical composition of groundwater. All groundwater samples are depleted with respect to δ(18)O (-11.71 to -9.4 ‰) and δD (-66.26 to -48.41 ‰). The δ(18)O and δD isotope ratios for surface and groundwater had a similar range and showed high deuterium excess (d-excess) (21.11 to 31.16 ‰). The high d-excess in water samples is because of incoming vapors from the UL mixed with an evaporated moisture flux from the Urmia mainland and incoming vapors from the west (i.e., Mediterranean Sea). Some saline samples with low B/Cl and Br/Cl ratios had depleted δ(18)O and δD. In this case, due to freshwater flushing, the drilled wells in the coastal playas and salty sediments could have more depleted isotopes, more Cl(-), and consequently smaller B/Cl and Br/Cl ratios. Moreover, the results of hydrochemical facies evolution (HFE) diagram showed that because of the existence fine-grained sediments saturated with high density saltwater in the coastal areas that act as a natural barrier, increasing the groundwater exploitation leads to movement of freshwaters from recharge zones in the western mountains not saltwater from UL. The highly permeable sediments at the junction of the rivers to the lake are characterized by low hydraulic gradient and high

  6. High-levels of microplastic pollution in a large, remote, mountain lake.

    PubMed

    Free, Christopher M; Jensen, Olaf P; Mason, Sherri A; Eriksen, Marcus; Williamson, Nicholas J; Boldgiv, Bazartseren

    2014-08-15

    Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km(-2), Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Simulating the decadal- to millennial-scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska

    NASA Astrophysics Data System (ADS)

    Kessler, M. A.; Plug, L. J.; Walter Anthony, K. M.

    2012-06-01

    Thermokarst lakes alter landscape topography and hydrology in widespread permafrost regions and mobilize significant permafrost carbon pools, including releasing methane (CH4) to the atmosphere. Despite this, the dynamics of lake evolution, permafrost thawing, and carbon mobilization are not well known. We present a 3-D numerical model of thermokarst lakes on organic-rich yedoma permafrost terrains with surface water flow and pooling naturally defining lakes that deepen, expand laterally, and drain due to talik formation, bank retreat, and both gradual and catastrophic drainage. We predict the 3-D pattern of microbial methane production within the talik over time. As a first model test and calibration, beginning with small protolakes, we simulated 10,000 years of evolution of Pear and Claudi lakes, two neighboring thermokarst features on the northern Seward Peninsula, Alaska. Simulated lakes approximated observed bathymetry, but results are sensitive to initial topography and soil ice content. Local topography caused markedly different dynamics for the two lakes. Pear expanded rapidly across low-relief topography, fully drained multiple times, and released little methane in later stages due to Pleistocene carbon depletion by the first and largest lake generation. Claudi grew slowly and continuously across high-relief topography, forming high subaerial banks; partial drainages left remnant horseshoe lakes that continued to expand into virgin yedoma, mobilizing carbon at roughly the same rate irrespective of lake drainage. The ˜2× discrepancy between simulated CH4 production and observed emission rates in Claudi likely results from misestimation of hot spot ebullition, labile carbon content, CH4:CO2 production ratio, or microbial CH4 oxidation.

  8. The preglacial sediment record of Lake Ladoga, NW Russia - first results from a multi-proxy study on a 23 m sediment record

    NASA Astrophysics Data System (ADS)

    Gromig, R.; Melles, M.; Wagner, B.; Krastel, S.; Andreev, A.; Fedorov, G.; Just, J.; Wennrich, V.; Savelieva, L.; Subetto, D.; Shumilovskikh, L.

    2016-12-01

    The joint German-Russian project 'PLOT - Paleolimnological Transect' aims to recover lake sediment sequences along a more than 6000 km long longitudinal transect across the Eurasian Arctic in order to study the Late Quaternary climatic and environmental history. The eastern end of the PLOT transect is formed by the well-studied record from Lake El'gygytgyn (NE Siberia). Lake Ladoga (N 60°50' E 31°30') is Europe's largest lake, both by size and volume and forms the westernmost end of the transect. Whereas modern sedimentation as well as the Holocene and Late Glacial history of Lake Ladoga have intensely been studied, the preglacial history of the lake is poorly studied to date by sediment cores drilled in the 1930's. A seismic survey of Lake Ladoga in summer 2013 revealed unconformities in the western lake basin, which may separate preglacial sediments in isolated depressions from Late Glacial and Holocene sediment successions above. A 23 m long sediment core (Co1309) was retrieved from one of these depressions. Core Co1309 was investigated by XRF-scanning, magnetic susceptibility measurements, as well as pollen, grain-size, and bio-geochemical analyses. An age-depth model combining radiocarbon, OSL, and paleomagnetic dates is in progress. Both, the pollen results and the OSL ages from the base of the record indicate a deposition during MIS 5e (Eemian). The well sorted reddish sands from this interval contain dinoflagellates suggesting at least brackish conditions, likely due to the existence of a gateway connecting a precursor of the Baltic Sea with the White Sea via Lake Ladoga. The Late Glacial sequence consists of greyish varved clays of decreasing thickness upwards with sporadically intercalated sand layers. The Holocene sequence is composed of brownish diatomaceous silty clay with minor proportions of sand.

  9. Lake

    ERIC Educational Resources Information Center

    Wien, Carol Anne

    2008-01-01

    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  10. Study of speciation and size fractionation of trace element between soil solution, bog, river and lake within a boreal watershed (North Karelia, NW Russia) using fractional filtration

    NASA Astrophysics Data System (ADS)

    Ilina, Svetlana M.; Lapitsky, Sergey A.; Alekhin, Yuriy V.; Pokrovsky, Oleg S.; Viers, Jerome

    2010-05-01

    This work is aimed at studying the evolution of migration forms of true dissolved compounds and colloidal entities using an integrated approach of molecular mass distribution and differences in the association of trace elements (TE) with organic matter (OM) or Fe colloids in the system soil water-bog-river-lake. Characterization of TE speciation with colloids during TE migration from the site of colloids origin (bog and soil solutions) towards the transit zone (river) and finally to the deposition, accumulation or transformation zone (lake) is a main fundamental task of this problem. The objects of study include a small stream watershed Vostochniy and the river Palayoki (North Karelia, Russia). The water samplings were performed in July and August 2008 and 2009 and included soil solution, nourishing bog, the middle part of the brook originated from the swamp, the mouth of the brook and the lake Zipringa. We sampled large volumes (50 - 100 liters), and we applied, directly in the in-field-installed "clean laboratory" the sequential frontal filtration and ultrafiltration of samples through the filters of progressively decreasing poresize 100, 20, 10, 5, 0.8, 0.4, 0.2 and 0.1 microns; 100 kDa (0.0065 micron), 10 kDa (0.003 micron) and 1 kDa (0.0014 micron). This allowed separation of organic matter, coarse and fine particulate matter and colloids. All filtrates and selected retentates were analyzed for a wide range of macro-and micronutrients using ICP-MS. In filtrates of the river water, a significant decrease of iron concentration occurred in the range of 5 micron to 0.22 micron and from 100 kDa to 1 kDa. For alkali and alkaline earth elements (Mg, K, Ca), as well as for Cu, Ni, Cr the concentrations changed after passing through the 10 kDa membrane. Na concentration remains constant in all filtrates. The filtrates of the soil solution are characterized by a significant decreases in Na, K, after 0.1 micron, Ca, Cu in the range of 0.22 micron - 100 kDa and Mg, Ni in

  11. Using radon-222 and radium-226 isotopes to deduce the functioning of a coastal aquifer adjacent to a hypersaline lake in NW Iran

    NASA Astrophysics Data System (ADS)

    Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh

    2017-10-01

    This study aims to assess the hydrogeochemistry of coastal groundwater, the occurrence of 222Rn and 226Ra, and their isotopic response to salinity and associated chemical compositions of groundwater in the coastal Urmia Aquifer (UA) at the western side of Urmia Lake (UL). The results of the PCA show that 87.3% of groundwater chemistry changes are controlled by six principal components. The interaction between groundwater and coastal igneous and metamorphic rocks in eastern areas (next to the UL) results in complex hydrogeochemical conditions than western areas. Based on correlation of U and salinity, some coastal samples display conservative and the others non-conservative behaviors. Differed from most previous studies, 226Ra and 222Rn concentrations in coastal groundwater samples of UA do not show a good correlation with salinity. Given 10% of groundwater 222Rn is originated from host rocks, the radon concentrations recorded in the coastal groundwater samples are relatively in range that can effectively be supplied by the local rocks (5-49 Bq/l). Results of different chemical and isotopic parameters in this area indicate that there is no direct connection between fresh groundwater and UL saltwater. This is because that the hard and thick salty layer in the lakebed acts as an impermeable barrier to prevent the underground hydraulic connection. Results show that removing the salty layer of UL as an option to progress in rehabilitation program of this lake may result in more hydraulic connection between the lake and groundwater resources in some areas.

  12. Au-only and Au-Ag-Base metal ores of the Sioux Lookout-Sturgeon Lake area, NW Ontario - a comparison

    SciTech Connect

    Brown, P.E.

    1985-01-01

    Contents of fluid inclusions in quartz from Au-vein ores in the Sioux Lookout-Sturgeon Lake area vary substantially. The ores are hosted by felsic and mafic metavolcanic rocks as well as felsic plutonic rocks. The host rocks are part of the Wabigoon Subprovince and are located south of the better known Pickle Lake area of the Uchi Greenstone belt. Samples from the Moede Showing south of Savant Lake contain abundant sphalerite and chalcopyrite. The 10-30 micron inclusions have halite cubes and often a second daughter salt. Salt dissolution occurs near 200/sup 0/C with liquid-vapor homogenization (L-VH) between 390 and 450/sup 0/C. Inclusions often leak near 350/sup 0/C and decrepitate above 450/sup 0/C. Most of the Au-only vein ores contain dominantly water-carbon dioxide fluids with either 2 or 3 phases at room temperature (22/sup 0/C). Quartz from the active Goldlund mine contains CO/sub 2/-rich, 2 and 3 phase inclusions. Samples from the past producing St. Anthony mine contain inclusions with 60% CO/sub 2/ which homogenize between O and 10/sup 0/C, corresponding to CO/sub 2/ densities between 0.84 and 0.93 g/cc. Inclusions from the more base metal-rich Coveney Pit have much more variable H/sub 2/O-CO/sub 2/ ratios and generally CO/sub 2/ L-VH temperatures in the range 19-28/sup 0/C. The majority of measured isochors extrapolate to between 1.1 and 2.9 kb at a temperature of 350/sup 0/C and 1.5 and 3.6 kb at 450/sup 0/C. These pressures, temperatures and salinities are consistent with the general lack of evidence for boiling Archean gold deposits and support the late epigenetic origin for most of the greenstone-hosted gold ores.

  13. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhong; Jia, Hongjuan

    2017-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  14. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhong; Jia, Hongjuan

    2016-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  15. Determination of Sinkholes with Different Geophysical Techniques; A Case Study in Yarımburgaz, Küçükçekmece Lake NW Istanbul, Turkey

    NASA Astrophysics Data System (ADS)

    Karabulut, Savas; Cengiz Cinku, Mualla; Tezel, Okan; Dedecan, Hasan; Oygo, Azat

    2016-04-01

    The Yarımburgaz cave which is located in the city of Istanbul, NW Turkey plays an important host to the first human culture and preserve significant archaeological and paleontological resources. The cave was formed as a result of a subterranean stream erosion on the limestones of the Eocene Kırklareli formation. It has been reported that a double cave with upper and lower entrance chambers exist, although no geophysical research was conducted to detect the cave's trunk passages and the extend of the sediment fill inside the cave. The aim of this study was to test the preferred order for detection the response to different geophysical methods applied on the cave. We therefore carried out an a series of geophysical study to determine the size, position, and depth of sinkholes inside the caves. Integrated methodological approaches including multichannel analysis of surface wave (MASW) 2- microtremor array method, 3-single station microtremor measurements, 4- electrical tomography (ET) measuruments and 5-microgravity imaging showed that the geophysical response was succesfully applied. Based upon the flow-chart we concluded that the microgravity survey should be applied as a first step to detect the air-filled void and the geometry of the cave. The electric tomography method was well applied showing high resistivity values across the voids. The surface wave method showed that the low-velocity zones are detected in various locations of the cave. In addition we the results of MASW and ReMi methods showed clearly the density variation in the lateral direction. Fundamental frequency value above void decraese according the properties of geological units in lateral directional, especially when they are engineering rock like limestone.

  16. Assessing the chemical behavior and spatial distribution of yttrium and rare earth elements (YREEs) in a coastal aquifer adjacent to the Urmia Hypersaline Lake, NW Iran.

    PubMed

    Sohrabi, Nassim; Kalantari, Nasrollah; Amiri, Vahab; Nakhaei, Mohammad

    2017-07-15

    This study aims to shed light on the seasonal behavior of yttrium and rare earth elements (YREEs) in the Urmia Aquifer (UA), in the immediate vicinity of Urmia Lake (UL) in Iran. Samples of groundwater, collected under dry and wet conditions in coastal wells of UA, suggest a large degree of variability in both YREE abundance and normalized patterns. Although weathering or water-rock interactions (between the surface/groundwater and rock samples) were predicted to be the most probable source in explaining YREEs in groundwater samples, results to the contrary indicate that the groundwater do not inherit aquifer rock-like YREE signatures in the study area; this might be due to the relative stability of YREEs during the process of water-rock interactions, which suggest that methods based on YREEs can be beneficial in discrimination of water sources. Furthermore, findings demonstrated no significant relationship between Ce/Ce* and salinity (0.08 and 0.05 in wet and dry seasons, respectively), and between Eu/Eu* and salinity (0.1 and -0.04 in wet and dry seasons, respectively). Dissimilarity of patterns of YREEs in rock and water samples reveals YREEs as no conservative tracers in determining the UL saltwater intrusion into coastal groundwater. Therefore, the groundwater YREE concentrations and fractionation patterns in UA warrant controlling by coastal aquifer need to be controlled by other chemical weathering, adsorption, desorption, and solution complexation reactions. Finally, comparison of REE concentration values in groundwater samples with corresponding indicative admissible drinking water concentrations (IAC) demonstrated their suitability for drinking purposes.

  17. Generation of an Archaean H/sub 2/O-CO/sub 2/ fluid enriched in Au, W and Mo by fractional crystallization in the Mink Lake intrusion, NW Ontario

    SciTech Connect

    Burrows, D.R.; Spooner, E.T.C.

    1985-01-01

    Fractional crystallization (FC) of the post-tectonic trondhjemitic Mink Lake intrusion in NW Ontario resulted in a residual H/sub 2/O-CO/sub 2/ low salinity fluid with an isotopic composition (delta /sup 13/C/sub cc/ x = -3.3 per thousand +/- 0.4 per thousand (1s), delta/sup 18/O/sub cc/ + 10.7 to 15.9 per thousand, deltaD/sub FI/ -70 +/- 9 per thousand (1s) and delta /sup 34/S/sub py/ +0.4 to +2.90 per thousand) compatible with magmatic derivation and extremely similar to that in vein quartz-carbonate-pyrite +/- scheelite, +/- tourmaline, +/- MoS/sub 2/ +/- telluride systems characteristic of major Archaean lode gold deposits. Inward FC of the granodiorite magma (69-71% SiO/sub 2/, Na/sub 2/O/K/sub 2/O = 1.6-3.9), as indicated by trace and REE data, produced a sequence of microgranites and aplitic dykes with mean values by INNA (n=10) for Au of 2.3ppb, Mo = 22ppm and W = 7.3ppm as compared to mean background values in the granodiorite of Au <1ppb, Mo less than or equal to 1ppm with W less than or equal to 3.7ppm (n=4). The latest aplites are observed to coexist with a H/sub 2/O-CO/sub 2/ mixture and are characterized by carbonate alteration selvages and minor MoS/sub 2/. Subsequent separation of the H/sub 2/O-CO/sub 2/ fluid and interaction with an otherwise fresh granodiorite within the already solidified southern margin, produced MoS/sub 2/ mineralized sub-horizontal quartz veins and larger tabular lenses of carbonate alteration without internal veining. Such zones are anomalously enriched (n=10) in Au (anti x = 153 pbb, range 2-570ppb) Mo (anti x 660ppm, range 1-2500ppm and W (anti x = 61 ppm, range 23-95 ppm).

  18. A 2400-year record of abrupt climate change from Almalou Crate Lake in NW Iran: Investigating the potential influence of solar variability on the climate of West Asia during late Holocene

    NASA Astrophysics Data System (ADS)

    Sharifi, A.; Pourmand, A.; Canuel, E. A.; Naderi Beni, A.; Lahijani, H. A.

    2013-12-01

    The Mediterranean climate of northwest Iran is influenced by mid-latitude Westerlies and the winter expansion of the Siberian Anticyclone. Given the significance of this region in development of human civilizations, high-resolution reconstructions of abrupt climate change are of particular interest during the Holocene. Almalou Crater Lake sustains the growth of plants inside the crater of a dormant volcanic cone on the eastern flank of the Sahand volcanic district in NW Iran. At an elevation of 2491 m.a.s.l., the crater is exclusively fed by rainfall during the spring and fall and snowfall during the winter. Preservation of organic matter within the crater can potentially record changes in atmospheric deposition and paleo-environmental conditions over this region. To reconstruct changes in atmospheric aeolian input, we present a high-resolution (sub-decadal) multi-proxy record of climate variability during the last 2400 years from a 3-m peat core recovered from the crater peat bog. Radiocarbon dates of eight samples along the core show a nearly constant rate of accumulation (7.7 mm yr-1, R2=0.98) since 2404×25 cal yr BP. Downcore X-ray fluorescence measurements of selected conservative lithogenic elements (e.g., Al, Si, and Ti) as well as redox-sensitive elements (e.g., Fe and Rb) at 10 mm intervals reveal several periods of elevated abundances related to enhanced atmospheric dust deposition. The co-variations between relative abundances of conservative and redox-sensitive elements as a function of time show significant agreement and attest to the ombrotrophic nature of the entire record. Intervals of enhanced dust deposition inferred from XRF data reveal three short episodes (~ 150-y) at 450-600, 1150-1300, and 1400-1550 cal yr BP, and one prolonged period (500 y) of dust accumulation from 1600 to 2070 cal yr BP. These intervals of high atmospheric dust coincide with historical records of drought and famine in Iran since 2000 BP. Wavelet analysis conducted on the

  19. Better Buildings NW Ohio

    SciTech Connect

    Moyer, Kevin

    2015-03-04

    Districts or ESIDs and what is nationally known as Property Assessed Clean Energy or PACE districts and PACE financing. The project methodology followed the identify, develop, implement, monitor and measure format. These districts began in Toledo and adjoining areas and are expanding to TLCPA’s 28 county financing agency geographic footprint. What began as the Toledo Ohio Advanced Energy Improvement Corporation is now doing business as the Northwest Ohio Advanced Energy Improvement District recognizing it expansion into creating and financing other districts in NW Ohio. The program has been sought out as an advisor by major communities and states in the process of developing similar legislation and programs and has become one of the largest most successful PACE energy improvement and financing districts in the US. The program and the energy district focused on transforming energy use, delivery, conservation and renewable energy as “options of first choice”. The significant energy savings paid for many of the improvements and created a financially viable program well beyond the grant period. The program has become a model within the State of Ohio and Nationally on how to implement and finance projects in broad energy districts including how to evolve and integrate several financing methodologies. It is a unique utilization of revolving loan funds and energy bond pooling with revenue backing primarily from energy improvement special assessments on commercial properties along with some power purchase agreement (PPA) and loan agreement revenue. The program has also incorporated Qualified Energy Conservation Bonds, State of Ohio Energy Loans (SEP), utility rebates, solar and renewable energy certificates, renewable tax incentives and grants, and owner funded equity as additional program leverage and funding. Other keys to this success have been a continual simplification and refinement of the application and documentation process to make funding available easily and

  20. Oxygen isotopic composition of bulk carbonates in recent sediments from Lake Kuhai (NW China) and implications for hydroclimatic changes in headwater areas of the Yellow River on the northeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Xiangzhong; Zhou, Xin; Liu, Weiguo; Fan, Guoqing; Cheng, Peng; Xu, Liming

    2017-02-01

    The water resource issue is one of the most significant problems in the Yellow River basin, and has received much attention from the public and government because of the dramatically decreased Yellow River streamflow in the last several years. In this study, oxygen isotopic compositions of bulk carbonates from Lake Kuhai in the headwaters of the Yellow River were evaluated as an indirect proxy of past Yellow River streamflow in order to place the recent flow reduction in a long-term context. The results indicated that δ18O values of bulk carbonates from core KHC14-1 generally vary with changes in the Yellow River streamflows related to the precipitation/evaporation (temperature) ratio above the Tangnaihai hydrological station over the past 50 years. In general, the Yellow River streamflow in the headwaters area continued to decrease from the early 1980s to the late 1990s because of decreased precipitation and increased temperature. Then, the streamflow increased with enhancing precipitation over the last two decades. In addition, δ18O values of bulk carbonates in the Lake Kuhai core roughly correlate with the streamflows of the upper reaches of the Yellow River recorded by tree ring width over the past 800 years. The enriched δ18OBC values showed that the precipitation/evaporation (P/E) ratio or streamflow was very low and the climate might be very dry in the middle of the 1400s CE in the headwaters of the Yellow River over the past 800 years. Our results suggested that changes in the P/E ratio or streamflow of the upper reaches of the Yellow River were dominated by variations in Indian Summer Monsoon precipitation over a long time scale, consistent with other records from the northeastern Tibetan Plateau.

  1. Holocene monsoon variability inferred from palaeolake sediments in NW India.

    NASA Astrophysics Data System (ADS)

    Dixit, Y.; Hodell, D. A.; Petrie, C. A.

    2012-04-01

    The plains of NW India encompasses arid, semi-arid to sub-humid zones and are characterized by numerous palaeolakes and playas. The sedimentary records from these water bodies provide a rich source of paleoclimatic information. We present a high-resolution, Holocene monsoon-variation record inferred from three palaeolakes lying across the precipitation gradient in NW India; palaeolake Karsandi in arid Rajasthan and palaeolake Riwasa, palaeolake Kotla Dahar in semi-arid and sub-humid regions, respectively, in Haryana plains. Laminated and massive gypsum deposits characterize Palaeolake Karsandi in the arid region. Oxygen isotopes are being measured on the gastropod shells and gypsum hydration of water (Hodell et al 2011) for a continuous isotopic record from Rajasthan. The oxygen isotope record from palaeolake Riwasa in the semi-arid region indicates the inception of a wet period at 9700-9500 cal yr (BP) with the establishment of a deep, permanent lake coinciding with the early Holocene maximum in the Indian monsoon. The deep, permanent-lake phase ended with a desiccation event at approximately 8200 BP coinciding with the '8.2kyr' weakening of the monsoon. In contrast, palaeolake Kotla Dahar, lying further east of Riwasa in the sub-humid region, receives 500-700mm annual rainfall. At Kotla Dahar, bulk CaCO3 (%), gastropod abundance and isotope data indicate that the deep lacustrine sequence ends at c.185 cm. Extrapolating from the AMS radio-carbon dated sediments at 135cm (4870-4650 BP) and 230cm (2000-1870 BP), places the 185 cm horizon at c.3970-3720 BP. Our results so far indicate that the Riwasa paleolake lying west of Kotla Dahar dries earlier than Kotla Dahar during the mid-Holocene. The precise date of the transition from a deep-lake water phase to an ephemeral lake in Kotla Dahar is pending, but the projected date suggests that the event coincides with the decline of the urban phase of the Indus Civilization at c. 3900 BP. These three lakes lying across

  2. Fish Lake, Utah - shallow seismic investigation of a lake-filled high-altitude graben

    NASA Astrophysics Data System (ADS)

    Harris, M. S.; Oliviera-Manna, M.; Bailey, C.; Marchetti, D. W.; Brunelle, A.; Abbott, M. B.; Larsen, D. J.; Stoner, J. S.; Grimm, E. C.; Donovan, J.; Anderson, L.; Power, M. J.; Chavez, V.; Carter, V.; Hart, I.

    2015-12-01

    Fish Lake formed in a portion of the 20-km x 2.5-km wide NE-SW trending graben within the High Plateaus of Utah, on the border between the Basin and Range to the west and the Canyon Lands east. This presentation focuses on the shallow seismic stratigraphic architecture of the lake. Marchetti et al. (this meeting) focuses details of a shallow core collected in 2014. With a lake surface at 2700m, avg. depth of 27m (max 37m), the lake is flanked NW by a 15° slope up to a formerly glaciated Hightop plateau (3545m) and is bound to the SE by a 30° NW facing slope off the Mytoge crest (3050m). The drainage basin is 74 km2 with ~75% of the catchment draining the Hightop from four distinct streams. Pelican Canyon (glaciated) and Doctor Canyon (unglaciated) provide most drainage into the basin, with Bowery and Twin creeks draining only the slope. These streams flow through organic-rich meadows at the edge of the lake. Only one small stream drains NW into the lake from the small Crater Lakes graben (2850m) off the Mytoge. Bathymetric surveys in the lake highlight a submerged moraine to the NE, a gently sloping bottom that reaches maximum depth off the steep wall to the SE, and small delta-form features off each of the creeks on the NW edge. Chirp seismic surveys (2-16 kHz) consistently penetrate the upper 40-m (up to ~55m). The oldest visible reflectors rise into the submerged moraine to the NE, ending in a complex set of truncated and discontinuous beds eluding to soft sediment push at the front of the glacier. Along the edge near the creeks to the NW, multiple sets of downlapping reflectors, gas pockets, and chaotic beds with lobate tops define what we interpret as deltaic deposition, possible lower lake levels with marsh systems, and slope failures. The majority of the lake is underlain by flat-lying reflectors that bound sedimentary packages spanning the entirety of the basin interior. The uppermost layers have recently been cored where seismic reflectors are continuous

  3. NW CSC annual report fiscal year 2013

    USGS Publications Warehouse

    Bisbal, Gustavo A.

    2013-01-01

    The Northwest Climate Science Center (NW CSC) was established in 2010 as one of eight regional Climate Science Centers created by the Department of the Interior (DOI). The NW CSC encompasses Washing-ton, Oregon, Idaho, and western Montana and has overlapping boundaries with three Landscape Conservation Cooperatives (LCCs): the Great Northern, the Great Basin, and the North Pacific. With guidance from its Executive Stakeholder Advisory Committee (ESAC), the NW CSC and its partner LCCs are addressing the highest priority regional climate science needs of Northwest natural and cultural resource managers. Climate Science Centers tap into the scientific expertise of both the U.S. Geological Survey (USGS) and academic institutions. The NW CSC is supported by an academic consortium with the capacity to generate climate science and tools in a coordinated fashion, serving stakeholders across the Northwest region. This consortium is primarily represented by Oregon State University (OSU), the University of Id-ho (UI), and the University of Washington (UW). The academic consortium and USGS provide capabilities in climate science, ecology, impacts and vulnerability assessment, modeling, adaptation planning, and advanced information technology, all necessary to address and respond to climate change in the Northwest. University members also recruit and train graduate students and early-career scientists. This Annual Report summarizes progress for the goals set out in the NW CSC Strategic Plan for 2012-2015 (http://www.doi.gov/csc/northwest/upload/Northwest-CSC-Strategic-Plan.cfm) and the NW CSC Work-plan for Fiscal Year (FY) 2013 (October 1, 2012 through September 30, 2013). The report follows the structure of the Strategic Plan, which describes the five core services (Executive, Science, Data, Communications, and Education and Training) provided by the NW CSC in support of the stated vision: Our Vision: To become nationally recognized as a best-practice model for the provision

  4. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This quarterly publication of the State Historical Society of Iowa features articles and activities for elementary school students. This summer issue focuses on the topic of lake life. The issue includes the following features: (1) "Where the Lakes Are Map"; (2) "Letter from the Lake"; (3) "Lake People"; (4)…

  5. 24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , AT SNOW FLAT. MOUNT HOFFMAN AT CENTER REAR. LOOKING NW. GIS: N-37 49 34.6 / W-119 29 58.2 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

  6. The morphometry of Lake Palmas, a deep natural lake in Brazil.

    PubMed

    Barroso, Gilberto F; Gonçalves, Monica A; Garcia, Fábio da C

    2014-01-01

    Lake Palmas (A = 10.3km2) is located in the Lower Doce River Valley (LDRV), on the southeastern coast of Brazil. The Lake District of the LDRV includes 90 lakes, whose basic geomorphology is associated with the alluvial valleys of the Barreiras Formation (Cenozoic, Neogene) and with the Holocene coastal plain. This study aimed to investigate the relationship of morphometry and thermal pattern of a LDRV deep lake, Lake Palmas. A bathymetric survey carried out in 2011 and the analysis of hydrographic and wind data with a geographic information system allowed the calculation of several metrics of lake morphometry. The vertical profiling of physical and chemical variables in the water column during the wet/warm and dry/mild cold seasons of 2011 to 2013 has furnished a better understanding of the influence of the lake morphometry on its structure and function. The overdeepened basin has a subrectangular elongated shape and is aligned in a NW-SE direction in an alluvial valley with a maximum depth (Zmax) of 50.7 m, a volume of 2.2×10(8) m3 (0.22 km3) and a mean depth (Zmv) of 21.4m. These metrics suggest Lake Palmas as the deepest natural lake in Brazil. Water column profiling has indicated strong physical and chemical stratification during the wet/warm season, with a hypoxic/anoxic layer occupying one-half of the lake volume. The warm monomictic pattern of Lake Palmas, which is in an accordance to deep tropical lakes, is determined by water column mixing during the dry and mild cold season, especially under the influence of a high effective fetch associated with the incidence of cold fronts. Lake Palmas has a very long theoretical retention time, with a mean of 19.4 years. The changes observed in the hydrological flows of the tributary rivers may disturb the ecological resilience of Lake Palmas.

  7. The Morphometry of Lake Palmas, a Deep Natural Lake in Brazil

    PubMed Central

    Barroso, Gilberto F.; Gonçalves, Monica A.; Garcia, Fábio da C.

    2014-01-01

    Lake Palmas (A = 10.3km2) is located in the Lower Doce River Valley (LDRV), on the southeastern coast of Brazil. The Lake District of the LDRV includes 90 lakes, whose basic geomorphology is associated with the alluvial valleys of the Barreiras Formation (Cenozoic, Neogene) and with the Holocene coastal plain. This study aimed to investigate the relationship of morphometry and thermal pattern of a LDRV deep lake, Lake Palmas. A bathymetric survey carried out in 2011 and the analysis of hydrographic and wind data with a geographic information system allowed the calculation of several metrics of lake morphometry. The vertical profiling of physical and chemical variables in the water column during the wet/warm and dry/mild cold seasons of 2011 to 2013 has furnished a better understanding of the influence of the lake morphometry on its structure and function. The overdeepened basin has a subrectangular elongated shape and is aligned in a NW-SE direction in an alluvial valley with a maximum depth (Zmax) of 50.7m, a volume of 2.2×108 m3 (0.22km3) and a mean depth (Zmv) of 21.4m. These metrics suggest Lake Palmas as the deepest natural lake in Brazil. Water column profiling has indicated strong physical and chemical stratification during the wet/warm season, with a hypoxic/anoxic layer occupying one-half of the lake volume. The warm monomictic pattern of Lake Palmas, which is in an accordance to deep tropical lakes, is determined by water column mixing during the dry and mild cold season, especially under the influence of a high effective fetch associated with the incidence of cold fronts. Lake Palmas has a very long theoretical retention time, with a mean of 19.4 years. The changes observed in the hydrological flows of the tributary rivers may disturb the ecological resilience of Lake Palmas. PMID:25406062

  8. Lake Tahoe

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate change, Lake Tahoe Total Maximum Daily Load (TMDL), EPA-sponsored projects, list of partner agencies.

  9. Lake Powell

    Atmospheric Science Data Center

    2014-05-15

    article title:  Lake Powell     View Larger Image ... format (14.42 mb)   This true-color image over Lake Powell was acquired by Multi-angle Imaging SpectroRadiometer (MISR) in late March 2000. Lake Powell was formed with the construction of the Glen Canyon Dam in 1963, on ...

  10. Lithospheric structure beneath NW Iran using regional and teleseismic travel-time tomography

    NASA Astrophysics Data System (ADS)

    Bavali, K.; Motaghi, K.; Sobouti, F.; Ghods, A.; Abbasi, M.; Priestley, K.; Mortezanejad, G.; Rezaeian, M.

    2016-04-01

    We compute a 2-D tomogram using the P wave arrival time readings from a temporary seismic experiment to study the seismic structure of the crust and upper mantle in NW Iran. The study area includes the western margins of the South Caspian Basin (SCB), and the Sahand and Sabalan post-collisional volcanoes in NW Iran. We invert 2780 regional and teleseismic relative P wave arrival times recorded by 23 stations along the seismic profile extending from the western shoreline of the Caspian Sea to Lake Urumieh. Our tomographic results show a higher-velocity region beneath the SCB. The observed higher velocities strongly correlate with the observed positive gravity anomalies over the southwestern margins of the Caspian Sea, suggesting an oceanic like nature for the SCB lithosphere. The tomographic results also show several lower-velocity anomalies in the crust. The Sabalan volcano is underlain by a low-velocity zone in the lower crust, which is most likely thermal in nature. In the Sahand region, the lower velocities are considerably shallower in depth and might be controlled by shallow sedimentary structures, as well as an anomalously warm upper crust. The shallow low-velocity regions are connected with deeper low-velocity zones 60-100 km deep in the upper mantle. This pattern points to a possible mantle source of post-collisional volcanism in NW Iran, i.e. the melting of a subducted slab.

  11. Glacier-induced Hazards in the Trans-Himalaya of Ladakh (NW-India)

    NASA Astrophysics Data System (ADS)

    Schmidt, Susanne; Dame, Juliane; Nüsser, Marcus

    2016-04-01

    Glaciers are important water resources for irrigated crop cultivation in the semi-arid Trans-Himalaya of Ladakh (NW-India). Due to global warming, many glaciers of South Asia have retreated over the last century and further ice loss will threaten local livelihoods in the long run. In the short term, an increase of flood events caused by melting glaciers and permafrost is expected for the Himalayan region. Beside large catastrophic events, small outburst floods are 'more' regularly reported for various parts of the region. This also holds true for the Trans-Himalayan region of Ladakh, where small glaciers exist at high altitudes. Caused by glacier retreat, a number of proglacial lakes have been formed, most of them dammed by ice filled moraines. The potential risk of these lakes is shown by recent reports on glacial lake outburst flood in the villages Nidder in October 2010 and Gya in August 2014. The 2014 flood destroyed several agricultural terraces, a new concrete bridge and two houses. Own remote sensing analyses shows the increase of a moraine dammed proglacial lake in the upper catchment area, which grew from about 0.03 to 0.08 km2 between 1969 and 2014. Because of the relatively stable altitude of the lake level, one can assume that the flood was caused by a piping process, initiated by melted ice bodies in the moraine. Already in the 1990s a small GLOF was observed in the village, which destroyed some fields. As in 2014, the lake was not completely spilled and a short-term decrease of the lake area is detectable in remote sensing data. Thus, further GLOF-events can be expected for the future. Beside physical risk factors, population growth and new infrastructure development along the streams and valleys increases potential damages of floods. Therefore, investigations are required to estimate the risks of these small glacial lakes and the potential flood effected area for the case study of Gya as well as for the whole region of Ladakh. Remote sensing data are

  12. Quantitative Evaluation of a Rapid and Severe Early Holocene Drought in NW-Montana

    NASA Astrophysics Data System (ADS)

    Sperazza, M.; Hofmann, M. H.; Moore, J. N.; Hendrix, M. S.

    2005-12-01

    surface flow and geochemical model, using MINTEQ and WATEQ, to quantify the average precipitation and evaporation rate at ~7600 cal yr. BP. Model results suggest that the lake lowering had to occur over a very short period of time to avoid precipitation of CaCO3. More specifically, the draw down had to occur in less than 20 years to keep the concentration factor in the lake below saturation index. We suggest that the surface inflow into Flathead Lake was reduced to an annual average of about 10% of its modern day annual average flow. Our observational and modeling results are consistent with a variety of studies suggesting an ice-free NW-Montana during the early and middle Holocene with a significantly thinner winter snowpack and significantly lower river discharges. The average summer precipitation-derived flow into the lake during this time had to only be reduced by ~50%, assuming negligible spring runoff. Our hydrologic modeling efforts suggest that such a low inflow requires a dramatic drop in annual net precipitation to as low as 4cm/year, for several years, and an increase in evaporation rates 10 to 20% higher than today`s rates.

  13. National Dam Safety Program. Lake Timberline Dam (MO 30156), Upper Mississippi - Mississippi - St. Louis Basin, St. Francois County, Missouri. Phase I Inspection Report.

    DTIC Science & Technology

    1979-01-01

    State highway bridge over Big River, and one large chicken farm complex. Lake Timberline Dam is in the I intermediate size classification since it is...been observed: dip 750 - 800 strike 650 NW dip verticle strike 600 NW dip 8 0 strike 400 NW dip vertical strike NW I Some joints are horizontal...crossing, one State highway over Big River, and one large chicken farm complex. *I t I 1I I m SECTION 6 - STRUCTURAL STABILITY 6.1 EVALUATION OF

  14. 9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  15. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

    ... Swiss shores of Lake Constance at the town of Rorschach. Eutrophication, or the process of nutrient enrichment, is rapidly accelerated ... of the value of Lake Constance, efforts to mitigate eutrophication were initiated in the 1970's. MISR was built and is managed ...

  16. Lake Powell

    NASA Image and Video Library

    2007-09-20

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001. The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude. This image from NASA Terra satellite. http://photojournal.jpl.nasa.gov/catalog/PIA10614

  17. Great Lakes

    NASA Image and Video Library

    2017-09-28

    Bands of lake effect snow drift eastward from the western Great Lakes in this true-color image captured by the NOAA/NASA Suomi NPP satellite's Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on January 5, 2017. National Weather Service forecasters expect light to moderate lake effect snow showers to continue throughout the day today and into Saturday (1/7). Lake-effect snow forms when cold air passes over the warmer waters of a lake. This causes some lake water to evaporate into the air and warm it. This warmer, wetter air rises and cools as it moves away from the lake. When it cools, it releases that moisture and, if it’s cold enough, that moisture turns into snow. Although true-color images like this may appear to be photographs of Earth, they aren't. They are created by combining data from the three color channels on the VIIRS instrument sensitive to the red, green and blue (or RGB) wavelengths of light into one composite image. In addition, data from several other channels are often also included to cancel out or correct atmospheric interference that may blur parts of the image. Credit: NOAA/NASA/Suomi NPP via NOAA's Environmental Visualization Laboratory

  18. Holocene versus modern catchment erosion rates at 300 MW Baspa II hydroelectric power plant (India, NW Himalaya)

    NASA Astrophysics Data System (ADS)

    Draganits, Erich; Gier, Susanne; Hofmann, Christa-Ch.; Janda, Christoph; Bookhagen, Bodo; Grasemann, Bernhard

    2014-08-01

    300 MW Baspa II is India's largest private hydroelectric facility, located at the Baspa River which is an important left-hand tributary to the Sutlej River in the NW Himalaya (India). In this valley the Sangla palaeo-lake has been dammed around 8200 yr BP behind a rock-avalanche dam and Baspa II is located exactly on top of this palaeo-lake. This special location represents a very rare possibility to evaluate the short-term, river load and hydrological parameters measured during the planning and operational stages of Baspa II with the long-term parameters gained from the palaeo-lake sediments from the catchment. Sedimentological and geomorphological investigations of the lacustrine sediments have been used to reconstruct environmental changes during >2500 years of its existence. The Mid-Holocene erosion rates of the Baspa catchment estimated from the volume and duration of deposition of the exposed lake sediments are at 0.7-1.0 mm yr-1, almost identical with the modern erosion rates calculated from river gauge data from Baspa II. Several charcoal layers and charcoal pieces from the uppermost palaeo-lake levels around 5000 cal yr BP might be related to woodland clearance and they possibly represent one of the oldest evidences for human presence in the Baspa Valley during Neolithic time.

  19. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao )

    1996-01-01

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  20. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao

    1996-12-31

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil & gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  1. Continental rift-setting and evolution of Neoproterozoic Sindreth Basin in NW-India

    NASA Astrophysics Data System (ADS)

    Schöbel, Stefan; Sharma, Kamal K.; Hörbrand, Thorsten; Böhm, Theresa; Donhauser, Ines; de Wall, Helga

    2017-08-01

    The Neoproterozoic Sindreth Basin, NW India, and its surrounding area represent a half graben structure situated between the undeformed Malani Igneous Suite (MIS) in the west and a corridor of coeval Cryogenian ductile deformation, anatexis and granite intrusion in the east. The main lithologies observed in the basin are conglomerate, fanglomerate, debris flow and lake deposits derived from a nearby continental provenance, intercalated with concurrent mafic and felsic lava flows. Based on geological traverses across the strike of the basin, we propose a three-fold classification comprising Lower Clastic Unit and an Upper Clastic Unit and a Bimodal (basalt-rhyolite) Volcanic Unit separating the two. Tilting due to basin inversion and faulting has been observed; however, the rocks are unmetamorphosed and show undisturbed primary sedimentary features. The stratigraphic record of the basin is characteristic for deposition and magmatism in a fault-related continental setting. Implications of the findings have been discussed in the context of Neoproterozoic crustal dynamics in NW India. This study provides conclusive evidence for a continental setting for Sindreth Basin evolution and contests the recent models of active subduction setting (either back-arc basin or accretionary sediments over a subduction zone).

  2. White Lake AOC

    EPA Pesticide Factsheets

    White Lake is in Muskegon County along the eastern shore of Lake Michigan. It was named an Area of Concern on the Great Lakes under the Great Lakes Water Quality Agreement of 1987 and delisted in 2014.

  3. Principles of lake sedimentology

    SciTech Connect

    Janasson, L.

    1983-01-01

    This book presents a comprehensive outline on the basic sedimentological principles for lakes, and focuses on environmental aspects and matters related to lake management and control-on lake ecology rather than lake geology. This is a guide for those who plan, perform and evaluate lake sedimentological investigations. Contents abridged: Lake types and sediment types. Sedimentation in lakes and water dynamics. Lake bottom dynamics. Sediment dynamics and sediment age. Sediments in aquatic pollution control programmes. Subject index.

  4. Geomorphological analysis of the drainage system on the active convergent system in Azerbaijan, NW Iran

    NASA Astrophysics Data System (ADS)

    Kaveh Firouz, Amaneh; Burg, Jean-Pierre; Giachetta, Emanuele

    2016-04-01

    Rivers are important landforms to reconstruct recent tectonic history because they are sensitive to surface movements, especially uplift and tilting. The most important drainage basins of NW Iran are, from north to south, the Arax River, the Urmia Lake and the Ghezel Ozan River catchment. The morphology of the two adjacent catchments draining into the Caspian Sea, the Arax and Ghezel Ozan were studied to better understand the active tectonics and the effect of fault activity on morphology and erosion rate of NW Iran. We performed a quantitative analysis of channel steepness and concavity, from slope-area plots calculated from digital elevation model. This information has been combined with GPS velocity vectors and seismicity. Both catchments developed under uniform climate conditions. Results show that the two rivers are in morphological disequilibrium; they exhibit profiles with prominent convexities and knickpoints. The Arax River shows higher channel steepness and concavity index in downstream part of the profile. Distribution of knickpoints show scattered elevation between 700m and 3000m. GPS rates display shortening 10 ± 2 mma-1 and 14 ± 2 mma-1 in upstream and downstream, respectively. The river profiles of Ghezel Ozan River and its tributaries reveal more disequilibrium downstream where channel steepness and concavity index are higher than upstream. Most knickpoints occur between 1000m and 2000m. The amount of shortening by GPS measurement changes from upstream 13 ± 2 mma-1to downstream 14 ± 2 mma-1. Recorded earthquakes, such as Rudbar earthquake (Mw=7.3, 1990), are more frequent downstream. The Urmia Lake is surrounded by many small and large catchments. Only major catchments were considered for the analysis. One of the most active faults, the north Tabriz fault, corresponds to a major knickpoints on the Talkhe rud River. Concordance between river profile analysis, GPS and seismotectonic records suggests that the characteristics of the river profiles

  5. Lake Powell

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001.

    The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  6. 10. Side view of cane mill looking NW with steam ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Side view of cane mill looking NW with steam engine in background. - Hacienda Azucarera La Esperanza, Steam Engine & Mill, 2.65 Mi. N of PR Rt. 2 Bridge over Manati River, Manati, Manati Municipio, PR

  7. 4. Water treatment plant, view to NW, berm in foreground ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Water treatment plant, view to NW, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  8. BLDG 240, NW SIDE AND SW END. BLDG 241 IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BLDG 240, NW SIDE AND SW END. BLDG 241 IN BACKGROUND. - Naval Magazine Lualualei, West Loch Branch, Inert Storehouse Type, East of A Avenue between Third & Fourth Streets, Pearl City, Honolulu County, HI

  9. 35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL RAIL AND ROAD CUT IN DISTANCE. MONTEZUMA VALLEY OVERLOOK IS JUST TO RIGHT OF DISTANT ROAD CUT. - Mesa Verde National Park Main Entrance Road, Cortez, Montezuma County, CO

  10. 2. Photocopy of c. 1906 photograph looking NW at water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of c. 1906 photograph looking NW at water tower with mill pond and pump house in right center foreground; fuel oil storage tank in right background. - Laurel Valley Sugar Plantation, State Route 308, Thibodaux, Lafourche Parish, LA

  11. 7. NW corner of Blacksmith Shop showing roof truss connection ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. NW corner of Blacksmith Shop showing roof truss connection at top of brick wall. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Blacksmith Shop, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  12. 2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. - Philadelphia & Reading Railroad, Pedestrian Suspension Bridge, Foot of Sixth Street at Schuylkill River (formerly spanned Philadelphia & Reading main line at Reading Depot), Reading, Berks County, PA

  13. 6. Spiral staircase and brass firepole; located in NW corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Spiral staircase and brass firepole; located in NW corner of building, looking W. (Ceronie and Harms) - Rock Island Arsenal, Building No. 225, Rodman Avenue between Flagler Street & Gillespie Avenue, Rock Island, Rock Island County, IL

  14. Threequarter view looking NW at E (front) elevation with Train ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Three-quarter view looking NW at E (front) elevation with Train Shed extending behind. - Central of Georgia Railway, Passenger Station & Train Shed, Corner of Louisville (Railroad) Road & West Broad Street, Savannah, Chatham County, GA

  15. Perspective view NW by 310. Note the concrete pier extending ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view NW by 310. Note the concrete pier extending from the bridge in the foreground. This way to allow maximum water flow during floods and rainy periods. - Weaverland Bridge, Quarry Road spanning Conestoga Creek, Terre Hill, Lancaster County, PA

  16. 8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED IN SEQUENCE TO REDUCE OR CONCENTRATE BEET JUICE. - Utah Sugar Company, Garland Beet Sugar Refinery, Factory Street, Garland, Box Elder County, UT

  17. 2. Oblique view of north corner shows mostly NW side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of north corner shows mostly NW side and how stack connects to NE side of building. - Pacific Creosoting Plant, Boiler Building, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  18. 18. View looking NW towards Manhattan showing approach road in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. View looking NW towards Manhattan showing approach road in foreground. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  19. 17. Long distance view looking NW towards Manhattan showing access ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Long distance view looking NW towards Manhattan showing access ramps to bridge. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  20. 46. View looking NW towards lower Manhattan showing suspension system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. View looking NW towards lower Manhattan showing suspension system and superstructure. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  1. 3. Top surface of dock including railroad tracks; looking NW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Top surface of dock including railroad tracks; looking NW from shore end. Paving block mill location is partially visible on right one half of photo. - Pacific Creosoting Plant, West Dock, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  2. 9. View of NW corner showing truss framing at hip ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. View of NW corner showing truss framing at hip gable. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Carpentry Shop, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  3. Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain.

    PubMed

    Sanchís, J; Sánchez-Andrade, R; Macchi, M I; Piñeiro, P; Suárez, J L; Cazapal-Monteiro, C; Maldini, G; Venzal, J M; Paz-Silva, A; Arias, M S

    2013-01-16

    The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors. In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR=3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR=3), the youngest bovines (<2.5 years) and dairy cattle (Friesians). Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5-7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years. It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.

  4. Basal topography of Kronebreen, NW Svalbard

    NASA Astrophysics Data System (ADS)

    O'Sadnick, M.; Kohler, J.; Langley, K.; Kehrl, L. M.; Berthier, E.

    2010-12-01

    Kronebreen is a tidewater outlet glacier draining the icefield Holtedahlfonna, in the Kongsfjord area of NW Svalbard. Like most glaciers in Svalbard, Kronebreen has been in retreat since the first front positions were recorded, with the exception of a brief advance during the surge of the neighboring glacier Kongsvegen around 1948. Kronebreen is one of the fastest non-surging glaciers in Svalbard, with average annual velocities near the calving front of around 450 m/yr. It has not been possible until recently to calculate ice fluxes, however, since the bottom topography of Kronebreen has been unknown. In 2009, ice thickness data were obtained using low frequency radar from helicopter over the heavily crevassed Kronebreen. These new thickness data are combined with surface elevation maps, older ice depth data, and fjord bathymetry data to create an expanded bed map of the Kongsfjord area. Velocity data of Kronebreen derived from feature tracking of high-res visible imagery is also combined with thickness data to calculate estimates of flux throughout the glacier. Analysis of this new data will give a better understanding of Kronebreen's retreat history, its mass balance and flux into Kongsfjord, and help in making predictions of when and how quickly further glacier retreat may occur.

  5. Geology of the Naturita NW quadrangle, Colorado

    USGS Publications Warehouse

    Cater, Fred W.; Vogel, J.D.

    1953-01-01

    The Naturita NW quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles were mapped by the U.S. Geological Survey on behalf of the U.S. Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear ro be related to certain sedimentary structures in sandstones of favorable composition.

  6. Great Lakes

    USGS Publications Warehouse

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  7. Lake Bonneville

    USGS Publications Warehouse

    Gilbert, Grove Karl

    1890-01-01

    This volume is a contribution to the later physical history of the Great Basin. As a geographic province the Great Basin is characterized by a dry climate, changes of drainage, volcanic eruption, and crustal displacement. Lake Bonneville, the special theme of the volume, was a phenomenon of climate and drainage, but its complete history includes an account of contemporaneous eruption and displacement.

  8. NW-MILO Acoustic Data Collection

    SciTech Connect

    Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.; Jones, Mark E.

    2010-02-17

    There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight of Juan de Fuca, which contains part of the border between the U.S. and Canada. Table 1 lists the specific components used for the NW-MILO system. The acoustic sensor is a hydrophone permanently deployed at a mean depth of about 3 meters. In addition to a hydrophone, the other sensors in the system are a marine radar, an electro-optical (EO) camera and an infra-red (IR) camera. The radar is integrated with a vessel tracking system (VTS) that provides position, speed and heading information. The data from all the sensors is recorded and saved to a central server. The data has been validated in terms of its usability for characterizing the

  9. Multiproxy Investigations on Tso Moriri Lake, Indian Himalayas provide clues to climate controlled lake level changes

    NASA Astrophysics Data System (ADS)

    Mishra, P. K.; Dietze, E.; Schettler, G.; Anoop, A.; Menzel, P.; Gaye, B.; Jehangir, A.; Prasad, S.

    2013-12-01

    The available data on Holocene climate variability from Asia indicates spatio-temporal changes in the precipitation over this vast region. Timing, duration, regionality, and causes of these fluctuations are not well understood, especially over the Indian subcontinent. We present high resolution studies on radiocarbon dated lake sediments from the Tso Moriri lake, NW Himalaya (78°14'-78°25'N and 32°40'-33°02'E; altitude: 4500 m, max depth: 105m). The lake is situated in the transition zone between both mid latitude westerlies and Indian summer monsoon zone. Detailed geochemical, sedimentological and statistical analysis of modern surface sediments from the lake, and the catchment area has been carried out to develop multiple proxies to infer past environmental conditions. Based on our investigations, we concluded that i) the allochthonous contribution is controlled by meltwater inflow and monsoon runoff, and the sedimentological and mineralogical characteristics can be used to infer the relative contributions of the two transport mechanisms; ii) the formation of authigenic aragonite is related to lake water chemistry which in turn is governed by the relative changes in melt water inflow and monsoon precipitation; iii) grain size variability reflects the energy and mode of transport and can be used as an indicator of shore line proximity and lake level changes. Based on the developed proxies on modern sediments we have identified five different periods of lake level changes from the core sediments retrieved from the deepest part of the lake (105 m water depth): a) Period V: (728.0-585.0 cm; >19.50 cal kyr. BP): Lake establishment. b) Period IV: (425.0-585 cm; 19.50-16.56-cal kyr BP): Shallow lake with high organic productivity. c) Period III: (320.0-425.0 cm; 12.52-16.56 cal kyr BP): Increasing the lake level marked by the dominance of medium silt. d) Period II: (130.0-320.0 cm; 12.52- 4.1-cal kyr. BP): Highest lake level, possibly linked to increased monsoon

  10. Ancient lakes on Mars?

    NASA Technical Reports Server (NTRS)

    Goldspiel, J. M.; Squyres, S. W.

    1989-01-01

    The valley systems in Mars' ancient cratered terrain provide strong evidence for a warmer and wetter climate very early in planetary history. The valley systems in some instances debouch into closed depressions that could have acted as local ponding basins for the flow. A survey of the Martian equatorial region shows that numerous local depressions at the confluence of valley systems exist. These depressions (approximately 100 km) typically are characterized by many valleys flowing into them and few or none flowing out. If ponding did take place, these basin would have contained lakes for some period during Mars' early warmer epoch. Although the collection basins are numerous, location of ones that have not suffered significant subsequent geologic modification is difficult. Some morphologic features suggest that volcanic lavas may have filled them subsequent to any early fluvial activity. Two detailed maps of valley systems and local ponding basins in USGC 1:2,000,000 subquadrangles were completed and a third is in progress. The completed regions are in Mare Tyrrhenum (MC-22 SW) and Margarifter Sinus (MC-19 SE), and the region in progress is in Iapygia (MC-21 NW). On the maps, the valley systems and interpreted margins of ponding basins are indicated. The depressions are of interest for two reasons. First, the depressions were surely the sites in which the materials eroded from the valleys were deposited. Such sediments could preserve important information about the physical conditions at the time of deposition. Second, the sediments could preserve evidence of water-atmosphere interactions during the early period of the Martian climate. Atmospheric carbon dioxide would dissolve in water, and solid carbonate minerals would tend to precipitate out to form carbonate sedimentary deposits. Formation of carbonates in this manner might account for some of the CO2 lost from the early more dense atmosphere.

  11. Active tectonics and Holocene versus modern catchment erosion rates at 300 MW Baspa II hydroelectric power plant (NW Himalaya, India)

    NASA Astrophysics Data System (ADS)

    Draganits, Erich; Grasemann, Bernhard; Gier, Susanne; Hofmann, Christa-Charlotte; Janda, Christoph; Bookhagen, Bodo; Preh, Alexander

    2015-04-01

    The Baspa River is one of the most important tributaries to the Sutlej River in the NW Himalaya (India). Its catchment is 1116 km2 in size, ranges from c. 6400 m asl to 1770 m asl and contains India's largest private hydroelectric facility, the 300 MW Baspa II. Geologically, the hydroelectric installation is located in the Higher Himalayan Crystalline, just above the active Karcham Normal Fault, which is reactivating the Early Miocene Main Central Thrust, one of the principal Himalayan faults. The area is seismically active and mass-movements are common. Around 8200 yrs BP the Baspa was dammed by a rock-avalanche dam, leading to the formation of the originally c. 260 m deep palaeo-lake Sangla palaeo-lake. Detailed sedimentological investigations and radiocarbon dating indicate that the palaeo-lake was completely filled with sediments until c. 5100 yrs BP. This makes the Sangla palaeo-lake to a very rare example of a mass-movement dam with very long duration and its lacustrine sediments represent a valuable archive for geological processes and environmental proxies within the Baspa catchment during the c. 3100 years of its existence - which are the aim of our study. At least 5 levels of soft-sediment deformation have been recorded in the exposed part of the lacustrine sediments of Sangla palaeo-lake, including brecciated laminae, overturned laminae, folds, faults and deformation bands, separated by undeformed deposits. They are interpreted as seismites, indicating at least 5 earthquakes within 2500 years strong enough to cause liquefaction. The 300 MW Baspa II hydro-electric power plant has been built exactly on top of this palaeo-lake. This special location represents a very rare possibility to evaluate the short-term, river load and hydrological parameters measured during the planning and operational stages of Baspa II with the long-term parameters gained from the palaeo-lake sediments from the catchment. This data show that the Mid-Holocene erosion rates of the

  12. Lake Mackay, Australia

    NASA Image and Video Library

    2014-10-27

    This image from NASA Terra spacecraft shows Lake Mackay, the largest of hundreds of ephemeral lakes scattered throughout Western Australia and the Northern Territory, and is the second largest lake in Australia.

  13. Emplacement of the Solarya Pluton (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Ünal, Alp; Altunkaynak, Şafak

    2017-04-01

    The Solarya pluton is one of the major plutons located in NW Anatolia. It consists of three plutonic rock groups: K-feldspar megacrystalline granodiorite (KFMG), microgranite-granodiorite (MGG) and haplogranite (HG). Also mafic dikes and mafic microgranular enclaves (MME) are common within the plutonic body. The northern and southern parts of the pluton present different textural properties. At the northern part of the pluton, K-feldspar megacrystalline granodiorite with porphyritic texture is dominant while southern part of the pluton is formed from microgranite-granodiorite with microgranular texture. Haplogranite, which is typical with its graphic/granophyric texture, outcrops between KFMG and country rocks as a thin aureole. The emplacement of the Solarya pluton began forcefully at the deeper levels of the epizone and then reached to shallow levels in the crust. The northern and southern part of the pluton displays textural and structural indicators of this different emplacement levels. At the northern part, between KFMG and the country rocks, pluton developed a narrow contact metamorphic zone characterized by the hornblend-hornfels facies. Additively, through the northern and eastern margin, the structural properties of the regional metamorphic rocks have changed depending on the emplacement of pluton indicating a forceful emplacement. The basement rocks at the southern boundary represent a "roof pendant" on the MGG. In some places of southern margin, MGG gradually passes into the subvolcanic rocks (microgranodiorite-quartzdiorite porphyries) which were emplaced into the ring and radial faults connected to pluton emplacement. The amphibole-plagioclase geothermobarometer results of Solarya pluton indicate that, for MGG 0.8-1.0 kb and 626-678 C and for K-feldspar megacrystalline granodiorite 1.8-2.3 kbar and 737-752 C pressure and temperature emplacement conditions are calculated. This data suggest that while the southern part of the pluton were emplaced into

  14. Quo vadis NW Black Sea benthic ecosystems?

    NASA Astrophysics Data System (ADS)

    Traian Gomoiu, Marian

    2016-04-01

    / thalasoterapy. Black Sea ecosystem restoration - Certainties and Uncertainties: Pressure on the Danube and other rivers has decreased, chemical discharges have decreased obviously, and yet there appear phenomena of water flowering - "red waters", hypoxia is still present at times and there is mass mortality of fish and other benthic organisms. Why? Signs of recovery should be considered cautiously and uncertainties may be resolved only in a longer time by increasing our scientific efforts. The results of the EU FP7 Project PERSEUS led to the identification of three important issues that should be resolved in order to achieve good environmental status: • Applying an adaptive management to increase the resilience of the ecosystems and to diminish the vulnerability of biodiversity; • Necessity of participative approach by stakeholders; • Identifying and obtaining adequate financial support for new R-D-I projects. Who are the actors in addressing and implementing the actions? • Academic educational and research institutions for adequate working condition; • More specialists trained for taxonomic groups; • Reasonable diversity of coordinating specialists, capable team leaders / satisfactory work packages; • Attracting NGO members towards nature conservation issues; • Resonable stakeholders committed to environmental issues. Studying the results of researches carried out by GeoEcoMar on the Romanian Black Sea coast in recent years, the author concluded that the major problems hampering progress towards a good ecosystem in NW Bent Black Sea are: • lack of diversity in the fields of research, both in theoretical and applied realms; • structural and functional consequences of ecological pressures and the disordered state of the ecosystems in the periods of paroxysmal eutrophication / pollution at the end of the 20th Century; • scarcity of data and knowledge on the Social-Economic System; • high costs of the new marine technology used directly in the sea and

  15. Groundwater hydrochemistry evolution in cyclone driven hydrological regimes, NW Australia

    NASA Astrophysics Data System (ADS)

    Skrzypek, G.; Dogramaci, S.; Grierson, P.

    2013-12-01

    Groundwater reserves supply the water needs of many arid regions around the world. Aquifer recharge in these regions is primarily depended on the amount and distribution of rainfall, coupled with exceedingly high rates of evaporation and interactions with both local and regional geomorphology and geology. In semi-arid northwest Australia, the majority of rainfall is delivered by large but infrequent cyclonic events and relatively more frequent but low intensity frontal systems. Changes to rainfall patterns due to global climate change may impact hydrological regimes, recharge rates and groundwater hydrochemistry. These changes may significantly restrict freshwater resources in the future. Between 2008 and 2012, we analysed >400 groundwater, surface and rainwater samples for stable isotope composition (δ2H and δ18O) and major ion chemistry. We then developed conceptual geochemical models of groundwater evolution for the Hamersley Basin (>100,000 km2) and a salt inventory for the Fortescue Marsh (the largest wetland in NW Australia) [1,2]. Fresh groundwater from the alluvium (-8.02 × 0.83‰) and fractured aquifers (-8.22 × 0.70‰) were hydrochemically similar and characterised by a very narrow range of δ18O [1]. In contrast, δ18O of saline and brine groundwater (TDS >10 g L-1) varies in wide range from +2.5 to -7.2‰ [2]. Most of the fresh and brackish groundwater reflects modern recharge and is evaporated by <20% prior to recharge. In contrast, highly saline and brine groundwater reflects mixing between modern rainfall, brackish water and older deep groundwater. The Fortescue Marsh primarily acts as a terminal basin for surface water from the upper Fortescue River catchment [2]. The stable isotope composition of the deep brine groundwater under the Marsh suggests a complex evolution, which cannot be explained by evaporation under current climatic conditions. The observed salinity and δ18O values may result from progressive evaporation from highly saline

  16. Active tectonics in Eastern Lunana (NW Bhutan): Implications for the seismic and glacial hazard potential of the Bhutan Himalaya

    NASA Astrophysics Data System (ADS)

    Meyer, M. C.; Wiesmayr, G.; Brauner, M.; HäUsler, H.; Wangda, D.

    2006-06-01

    Paleoseismological investigations, brittle fault analysis, and paleostrain calculations combined with the interpretation of satellite imagery and flood wave modeling were used to investigate the seismic and associated glacial hazard potential in Eastern Lunana, a remote area in NW Bhutan. Seismically induced liquefaction features, cracked pebbles, and a surface rupture of about 6.8 km length constrain the occurrence of M ≥ 6 earthquakes within this high-altitude periglacial environment, which are the strongest earthquakes ever been reported for the Kingdom of Bhutan. Seismicity occurs along conjugate sets of faults trending NE-SW to NNW-SSE by strike-slip and normal faulting mechanism indicating E-W extension and N-S shortening. The strain field for these conjugate sets of active faults is consistent with widespread observations of young E-W expansion throughout southern Tibet and the north Himalaya. We expect, however, that N-S trending active strike-slip faults may even reach much farther to the south, at least into southern Bhutan. Numerous glacial lakes exist in the investigation area, and today more than 100 × 106 m3 of water are stored in moraine-dammed and supraglacial lakes which are crosscut by active faults. Strong earthquakes may trigger glacial lake outburst floods, and the impact of such flash floods may be worst 80 km downstream where the valley is broad and densely populated. Consequently, tectonic models of active deformation have to be closely linked with glacial hazard evaluation and require rethinking and modification.

  17. View south up 27th Street rightofway NW (formerly Lyons Mill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View south up 27th Street right-of-way NW (formerly Lyons Mill Road) along western edge of Female Union Band Cemetery. Vegetation obscures the cemetery's terraces. - Mount Zion Cemetery/ Female Union Band Cemetery, Bounded by 27th Street right-of-way N.W. (formerly Lyons Mill Road), Q Street N.W., & Mill Road N.W., Washington, District of Columbia, DC

  18. Okanagan Lake, British Columbia

    NASA Image and Video Library

    1994-10-01

    STS068-155-011 (30 September-11 October 1994) --- (Okanagan Lake, British Columbia) View southward down the lake; Vernon is in the foreground, Kelowna just before the bend in the lake, and Penticton at the far end of the lake. Green crops are still vigorous despite the season (early October); clear-cuts dot the forested hillsides.

  19. 1. Creosote plant site (NW side) as viewed with a ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Creosote plant site (NW side) as viewed with a telephoto lens from Winslow ferry terminal. Eagle Harbor is in foreground. Buildings include Machine Shop on left, Boiler Building with stack, and Engine Room Building at center. Office is at far right next to tree. - Pacific Creosoting Plant, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  20. 3. View of partially excavated mill ruins looking NW showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View of partially excavated mill ruins looking NW showing unidentified pit in right foreground, masonry base for steam engine and cane mill in left center, purging house and chimney in background. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR

  1. 46. View of end bay of NW corner of mill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. View of end bay of NW corner of mill ruins showing where flue emerged from area of Jamaican Train. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR

  2. 5. View looking NW showing all major buildings on grandstand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. View looking NW showing all major buildings on grandstand side of track, beginning on left with Jockey Building, followed by the Paddock Club, Clubhouse, Original Grandstand, Second Grandstand and North Grandstand. (August 1993) - Longacres, 1621 Southwest Sixteenth Street, Renton, King County, WA

  3. 25. Stereo view version of Southeast Light looking NW with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. Stereo view version of Southeast Light looking NW with picket fence ca. 1890. From a contact print of a glass negative from the Mansfield Collection. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

  4. 17. Detail of base of 'Flying Ram' in NW corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Detail of base of 'Flying Ram' in NW corner of foyer. Camera is looking SW. First doorway beyond fountain leads to basement and men's lounge seen in WA-197-44. Second doorway leads to storefront corner at Seventh Ave. and Olive Way. (Aug. 1991) - Fox Theater, Seventh Avenue & Olive Way, Seattle, King County, WA

  5. 21. View of N room of mill looking NW through ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. View of N room of mill looking NW through arched passageway in wall separating N and S rooms. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR

  6. 30. Interior view of N room of mill, looking NW, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Interior view of N room of mill, looking NW, showing cast-iron columns and arches. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR

  7. 33. Interior view of N room of mill, looking NW, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. Interior view of N room of mill, looking NW, showing interior of W wall and cast-iron columns and arches. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR

  8. 70. View from Promenade looking NW towards Manhattan up one ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. View from Promenade looking NW towards Manhattan up one of the center main cables with Brooklyn Tower in background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  9. 42. View from top of Brooklyn Tower looking NW showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. View from top of Brooklyn Tower looking NW showing main cables and suspendors with lower Manhattan in the background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  10. MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON SE CORNER. NYSTROM VILLAGE, LIKE ATCHISON VILLAGE (HAER CA-326-N), HOUSED WORKERS DURING WORLD WAR II - Rosie the Riveter National Historical Park, Nystrom Village, Marina & Maine Streets, Richmond, Contra Costa County, CA

  11. 21. (Credit JTL) View looking NW at south elevations of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. (Credit JTL) View looking NW at south elevations of boiler room, old high service pumping room (1887) and beginning of 1900 filter room addition; wash water tank (1926) in background. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  12. 34. GENERAL VIEW LOOKING NW SHOWING (LEFT TO RIGHT), WIRE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. GENERAL VIEW LOOKING NW SHOWING (LEFT TO RIGHT), WIRE MILL NO. 1, WIRE MILL NO. 2, SCALE HOUSE, BUILDING NO. 69B. (ABUTS NJ-122E-33). - John A. Roebling's Sons Company, Kinkora Works, Support Systems, Roebling, Burlington County, NJ

  13. Perspective view of NW corner south feed pens and portion ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view of NW corner south feed pens and portion of middle feed pen on left. Main barn is in distance. Camera is pointed SE. - Kosai Farm, Feed Pens, B Street north of Northwest Twenty-ninth Street, Auburn, King County, WA

  14. 2. Oblique view of west corner shows mainly NW side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of west corner shows mainly NW side of partially dismantled building. In 1994 circular braces still supported retorts in which wood was processed with creosote. - Pacific Creosoting Plant, Engine Room Building, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  15. Rediscovery of lake balls in Lake Michigan

    USGS Publications Warehouse

    Schloesser, Donald W.; Hiltunen, Jarl K.; Owens, Randall W.

    1983-01-01

    For the first time in 70 years, the occurrence of a 'lake ball' in Lake Michigan is here reported in the literature. According to a published system of classification, the object we collected in 1978 was a 'false' lake ball. Dissection revealed that it was colonized by 5 chironomid larvae and 162 oligochaetes. The species and numerical proportions of the oligochaetes indicated that it was formed in or near the mouth of a eutrophic tributary rather than in the open waters of Lake Michigan where it was found. Because of their mobility, false lake balls may be ecologically important, serving as natural vehicles for the dispersal of invertebrates.

  16. Evidence for volcanism in NW Ishtar Terra, Venus

    NASA Technical Reports Server (NTRS)

    Gaddis, L.; Greeley, Ronald

    1989-01-01

    Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

  17. Lake Volta, Ghana

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of Lake Volta in Ghana was acquired March 31, 2002 by the Moderate Resolution Imaging Spectroradiometer (MODIS). Lake Volta is one of the world's largest artificially created lakes. Lake Volta is actually a reservoir formed from the damming of the Volta River, and extends 250 miles north of the Akosombo Dam. The lake covers an area of 8,482 square km. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  18. Lake Chad, Chad, Africa

    NASA Image and Video Library

    1990-04-29

    Africa's Lake Chad where the borders of Chad, Niger, Nigeria and Cameroon merge (13.0N, 14.0E) has been undergoing change for the past 25 to 30 years when it was first noticed that the lake is drying up. Since then, astronauts have been photographing it on a regular basis to record the diminishing lake bed. This lake was once the aproximate size of Lake Erie but is now only about half that size and is still receeding.

  19. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change.

    PubMed

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-25

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake.

  20. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change

    NASA Astrophysics Data System (ADS)

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-01

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake.

  1. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change

    PubMed Central

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-01

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake. PMID:26805936

  2. Tales from Two Cores: Bayesian Re-Analyses of the Summit Lake and Blue Lakes Pollen Cores

    NASA Astrophysics Data System (ADS)

    Hall, M.

    2016-12-01

    Pollen cores from Summit Lake and Blue Lakes in Humboldt Co., Nevada provide palaeoclimatic information for the last 2000 yearsin the NW Great Basin. Summit Lake is in the northern Black Rock Range (41.5 N -119.1 W) and is at an elevation of 1780 m. The Blue Lakes sit at an elevation of 2434 m in the southern Pine Forest Range (41.6 N -118.6 W). The distance between the two lakes is 33.5 km. The cores were originally taken to reconstruct the fire history in the NW Great Basin. In this study, stochastic climate histories are created using a Bayesian methodology as implemented in the Bclim program. This Bayesian approach takes: 1) a multivariate approach based on modern pollen analogs, 2) accounts for the non-linear and non-Gaussian relationship between the climate and the pollen proxy, and 3) accounts for the uncertainties in the radiocarbon record and climate histories. For both cores, the following climatic variables are reported for the last 2 kya: Mean Temperature of the Coldest month (MTCO), Growing Degree Days above 5 Centigrade (GDD5), the ratio of Actual to Potential Evapotranspiration (AET/PET). Because it was sequentially sampled,the Artemesia/Chenopodiaceae ratio (A/C), an indicator of wetness, and the Grasses/Shrubs (G/S) ratio, an indicator of thevegetation communities, is calculated for each section of the Summit Lake core. Bayesian changepoint analyses of the Summit Lake core indicates that there is no significant difference in the mean or variance of the A/C ratio for the last 2 kya cal BP, but there is a significant decrease in G/S ratio dating to circa 700 ya cal BP. At Summit Lake, a statistically significant decrease in the GDD5 occurs at 1.4-1.5 kya cal BP, and a significant increase in the GDD5 occurs for the last 200 ya cal BP. The GDD5 and MTCO for Blue Lakes has a significant increase at 600 ya cal BP, and afterwards decreases in the next century. The regional archaeological record will be discussed in light of these changes.

  3. Source field effects in the auroral zone: Evidence from the Slave craton (NW Canada)

    NASA Astrophysics Data System (ADS)

    Lezaeta, Pamela; Chave, Alan; Jones, Alan G.; Evans, Rob

    2007-09-01

    We present an investigation of source field effects on the magnetic fields from multiple long period magnetotelluric (MT) data collected on the floors of lakes throughout the Slave craton (NW Canada) from 1998 to 2000. Monthly and daily power spectra of the magnetic fields suggest a dynamic and seasonally varying source, with atypical geomagnetic activity in year 2000. Bounded influence MT and GDS responses were obtained for periods ranging between 80 and 25,000 s over selected monthly time segments. The responses at periods over 4000 s vary, suggesting source field effects. A frequency domain principal component (PC) method was applied to the array to investigate the spatial form of the source field variations. The PC analysis was tested with synthetic data from a regional 3D model with a uniform external source to study the sensitivity of the eigenvectors to conductivity structure, demonstrating a negligible influence with increasing penetration depth. We conclude that magnetic fields at periods near one half day are subject to a 1D polarized source of relatively homogeneous morphology over the survey area during any month recorded, except for the summer month of July 2000 that had particularly high geomagnetic activity. In general, the source space approaches two polarizations at periods below one half day, with the dominant NS component seen quasi-homogeneous over the survey area at periods over 1000 s.

  4. Lake Nasser and Toshka Lakes, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Nasser (center) and the Toshka Lakes (center left) glow emerald green and black in this MODIS true-color image acquired March 8, 2002. Located on and near the border of Egypt and Norther Sudan, these lakes are an oasis of water in between the Nubian (lower right) and Libyan Deserts (upper left). Also visible are the Red Sea (in the upper right) and the Nile River (running north from Lake Nasser). Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  5. Measurements, Fingerprint, Modeling - Compiling a sediment budget in a data scarce catchment in NW Jordan

    NASA Astrophysics Data System (ADS)

    Kraushaar, Sabine; Schumann, Thomas; Wilkinson, Scott; Ollesch, Gregor; Siebert, Christian; Vogel, Hans-Jörg

    2013-04-01

    In regard to the quantitative and qualitative water problems in Jordan the soil layer and its physical integrity is important to slow down runoff, guarantee infiltration, and a sensible parameter in terms of hydrologic modeling. Erosion harms this potential and needs to be better understood and quantified in the region. Therefore, a multiple response approach was implemented to compile a sediment budget for the research area Wadi Al-Arab in the NW of Jordan (263,5km2). The climate is Mediterranean to semi-arid with <300 to 550mm of rain in winter. Mainly marl and limestone of the Upper Cretaceous and the Paleocene make up the catchment's geology. The area is characterized by an agricultural basin in the east and an increase in relief energy to the west and south. Different field measurements were implemented on relevant sediment sources, such as olive orchards, agricultural fields, natural vegetated slopes and exposed rock with patchy vegetation as well as the Wadi Al Arab Dam Lake as the final sink. The focus involved the quantification of the yearly sediment yields and the deposition in the lake, respectively. In a second step a multiple sediment fingerprint was applied including the geochemical differentiation of the sources with inorganic elements and radio nuclides. The relative importance of each source could be calculated on the basis of lake sediment samples. Results of these two approaches cover different spatial scales and only partly integrate the transport way. Hence, they cannot be directly compared but consider the problem from different perspectives and are used in the final step to calibrate and validate the setup of the SedNet model (Wilkinson et al. 2008) for the catchment. The model offers the possibility to incorporate additional raster information, includes additional sources such as gully and bank erosion, and takes account for different areas of deposition according to the measured and regionalized discharge in the region. Its' implementation

  6. Lake Huron LAMPs

    EPA Pesticide Factsheets

    The approach in Lake Huron differs from the Lakewide Management Plans of the other Great Lakes: no formal binational designation of lakewide beneficial use impairments, nor extensive lakewide modeling of chemical loadings

  7. Lake Tahoe Projects

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate, change, Lake Tahoe Total Maximum Daily Load TMDL), EPA-sponsored projects, list of partner agencies.

  8. The Great Lakes

    EPA Pesticide Factsheets

    The Great Lakes form the largest surface freshwater system on Earth. The U.S. and Canada work together to restore and protect the environment in the Great Lakes Basin. Top issues include contaminated sediments, water quality and invasive species.

  9. Lakes on Titan

    NASA Image and Video Library

    2006-07-24

    The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan north pole

  10. Looking Down on Lakes

    NASA Image and Video Library

    2014-04-07

    NASA Cassini spacecraft peers down though layers of haze to glimpse the lakes of Titan northern regions. Titan has a hydrological cycle similar to Earth, but instead of water, Titan lakes and seas are filled with liquid methane and ethane.

  11. Lakes Ecosystem Services Online

    EPA Science Inventory

    Northeastern lakes provide valuable ecosystem services that benefit residents and visitors and are increasingly important for provisioning of recreational opportunities and amenities. Concurrently, however, population growth threatens lakes by, for instance, increasing nutrient ...

  12. National Lakes Assessment

    EPA Pesticide Factsheets

    The National Lakes Assessment is a collaborative, statistical survey of the nation's lakes. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  13. About Lake Tahoe

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate, change, Lake Tahoe Total Maximum Daily Load TMDL), EPA-sponsored projects, list of partner agencies.

  14. Lakes Ecosystem Services Online

    EPA Science Inventory

    Northeastern lakes provide valuable ecosystem services that benefit residents and visitors and are increasingly important for provisioning of recreational opportunities and amenities. Concurrently, however, population growth threatens lakes by, for instance, increasing nutrient ...

  15. Lake trout rehabilitation in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

    1995-01-01

    Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

  16. A Killer Lake

    ERIC Educational Resources Information Center

    Horvath, Thomas

    2005-01-01

    In 1986, Lake Nyos, a volcanic lake in Cameroon, released a huge amount of carbon dioxide gas, killing over 1,700 people in the surrounding area. This case study, developed for use in a limnology or aquatic biology course, explores that event, introducing students to concepts relating to lake formation, thermal stratification, and dissolved gases.…

  17. Lake Layers: Stratification.

    ERIC Educational Resources Information Center

    Brothers, Chris; And Others

    This teacher guide and student workbook set contains two learning activities, designed for fifth through ninth grade students, that concentrate on lake stratification and water quality. In the activities students model the seasonal temperature changes that occur in temperate lakes and observe the resulting stratification of lake waters. Students…

  18. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Chicago, IL. Great Lakes National Program Office.

    This book contains lesson plans that provide an integrated approach to incorporating Great Lakes environmental issues into elementary subjects. The book is divided into three subject areas: (1) History, which includes the origins of the Great Lakes, Great Lakes people, and shipwrecks; (2) Social Studies, which covers government, acid rain as a…

  19. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

    The Tenth Great Lakes Regional Meeting of the American Chemical Society met to assess current Chemical Research activity in the Great Lakes Basin, and addressed to the various aspects of the theme, Chemistry of the Great Lakes. Research areas reviewed included watershed studies, atmospheric and aquatic studies, and sediment studies. (BT)

  20. A Killer Lake

    ERIC Educational Resources Information Center

    Horvath, Thomas

    2005-01-01

    In 1986, Lake Nyos, a volcanic lake in Cameroon, released a huge amount of carbon dioxide gas, killing over 1,700 people in the surrounding area. This case study, developed for use in a limnology or aquatic biology course, explores that event, introducing students to concepts relating to lake formation, thermal stratification, and dissolved gases.…

  1. Great Lakes in January

    NASA Image and Video Library

    2017-09-28

    This image taken on January 13, 2015 from the Suomi NPP satellite's VIIRS instrument shows the Great Lakes and surrounding areas. The latest Great Lakes Surface Environmental Analysis (GLSEA) from the NOAA Great Lakes Environmental Research Laboratory shows total ice cover of 29.3% as of January 13th. Credit: NOAA/NASA/NPP Via NOAA Environmental Visualization Laboratory

  2. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

    The Tenth Great Lakes Regional Meeting of the American Chemical Society met to assess current Chemical Research activity in the Great Lakes Basin, and addressed to the various aspects of the theme, Chemistry of the Great Lakes. Research areas reviewed included watershed studies, atmospheric and aquatic studies, and sediment studies. (BT)

  3. Lake Effects: The Lake Superior Curriculum Guide.

    ERIC Educational Resources Information Center

    Beery, Tom; And Others

    This curriculum guide was launched in response to a need for Lake Superior-specific educational materials and contains lessons and activities that can be used to teach about Lake Superior. The lessons in this book are divided into four sections. Each of the first three sections has a background section that provides basic information about Lake…

  4. Lake Effects: The Lake Superior Curriculum Guide.

    ERIC Educational Resources Information Center

    Beery, Tom; And Others

    This curriculum guide was launched in response to a need for Lake Superior-specific educational materials and contains lessons and activities that can be used to teach about Lake Superior. The lessons in this book are divided into four sections. Each of the first three sections has a background section that provides basic information about Lake…

  5. Comparison between mechanisms of CO2 degassing from El Chichon volcanic lake, México, and Specchio di Venere lake, Pantelleria, Italia.

    NASA Astrophysics Data System (ADS)

    Jácome Paz, M. P.; Taran, Y.; Inguaggiato, S.; Collard, N.; Vita, F.; Pecoraino, G.

    2014-12-01

    We present results of the CO2 diffuse emission from the surface of two volcanic lakes: El Chichón (EC) in Mexico and Specchio di Venere (SV) on Pantelleria Island, Italy. Both lakes are drainless, have similar sizes (~2x105 m2) and similar input-output dynamics. However, they are drastically different in water chemistry. The SV lake is alkaline (pH >9) and of a high near constant salinity, whereas EC lake is acidic (pH 2.3) and of a low variable salinity. In the vicinity of both lakes there are thermal grounds with steam vents and hot springs and a high CO2 soil flux. The SV lake has high alkalinity (~70 meq/L), whereas the EC lake is characterized by high concentration of dissolved CO2. CO2 flux measurements from the surface of both lakes were made with the "floating" accumulation chamber. During the flux measuring, gas samples were taken for carbon isotopic analysis. Soil flux measurements were also made in the crater of El Chichon volcano and on the area adjacent to the SV lake. The preliminary results of CO2 fluxes indicate EC lake has a high CO2 flux with a mean value of 3500 g m-2 d-1, with the highest values alignment across NW-SE and NE-SW faults and a high degassing by bubbling gases, especially near the strongest NE fumarolic field. While SV has a mean value of the CO2 flux ~ 10 g m-2 d-1 and limited bubbling on the lake surface. High CO2 flux was measured from the soil near the lake at the Mofeta place. A net mean diffusion flux (without bubbles) from EC lake is about 350 times higher than that from SV lake (3500 g m-2 d-1 vs 10 g m-2 d-1). SV has the total CO2 flux by diffusion of ~3 ton d-1 from an area of 0.3 km2 and the total flux of 0.44 ton d-1 by bubbling areas at SW and S zones. The EC lake has the total CO2 flux of 840 ton d-1 from an area of 0.24 km2. The total CO2 output from SV is nevertheless about two times higher taking into account the seepage from the lake (~ 8 kg s-1) of highly carbonated water.

  6. The Enigma of the Origin of Round, Deep, Rimed Lakes in the Russian Heartland-Was Lake Smerdyachie Formed During the Impact of an Extraterrestrial Body?

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Gusiakov, V. K.; Kiselev, A.; Amelin, I. I.; Breger, D. L.; McCafferty, P.

    2014-12-01

    The heartland of Russia has many enigmatic deep lakes. Shallow lakes have a more obvious origin, perhaps as kettle lakes, oxbow lakes or subsidence features. Deep lakes, particularly round lakes with partial or complete rims are more problematic. Traditionally, round or nearly round lakes with rims are candidates for Holocene age impact structures. The problem is that there are too many such lakes in the Russian heartland- a minimum of 15 deep, round lakes with diameters between 0.2 and 3 km. Even with a possibly increased impact rate during the Holocene, these deep lakes would represent the entire budget of Holocene impacts concentrated in one small region of the Earth. We examine here Lake Smerdyachie, a previously proposed impact lake. Smerdyachie is perfectly round with a raised rim. It has a diameter of about 350 meters and a maximum water depth of over 30 m. The basement at Smerdyachie is at~40 meters depth. It consists of Carboniferous age carbonate rock with fossils of brachiopods, crinoids and gastropods. The overlying material consists of unconsolidated, sand and silt-sized, quartz-rich sediments. We found clasts of brachiopod, crinoid and gastropod-bearing Carboniferous carbonate rock up to 32 cm in diameter on the SE rim of Smerdyachie. These clasts are present over about 1/3 of the total circumference of the lake. We also made panned concentrates of the sediment on the rim. To the NW, the concentrated sediment has a negative magnetic susceptibility (-0.07 to -0.03 cgs units), consistent with a higher concentration of pulverized limestone. To the SE, the sediment has a positive magnetic susceptibility (0.06 to 0.35 cgs units). The areas of positive magnetic susceptibility lie on the SE two-thirds of the rim of the lake. The highest susceptibility value is from the sample taken closest to the lake shoreline on the SE rim. This spatial distribution of susceptibility could mean that there is a higher concentration of iron rich material on the SE side of

  7. The Last Transition From Extreme Glacial to Extreme Interglacial Climate in NW Patagonia: Regional and Global Implications

    NASA Astrophysics Data System (ADS)

    Moreno, P. I.

    2004-12-01

    The study of interhemispheric climate linkages during and since the last ice age has benefited from the recent development of high-resolution ice core and marine records from the mid- and high latitudes of the Southern Hemisphere. Few paleoclimate records from terrestrial environments in these regions, however, have the temporal continuity, time resolution, and adequate chronologic control to allow a detailed examination of the timing, rates, direction, and phasing of climate change at millennial timescales. Stratigraphic, palynologic, and charcoal records from small, high-sediment accumulating lakes in the Chilean Lake District (41ºS) afford useful data for examining the interval between the LGM to the early Holocene (25-8 ka, ka=cal kyr BP). Millennial-scale changes in glacier extent and vegetation patterns within this interval match key events both in the Northern Hemisphere and Antarctic records, in particular the EPICA Dome C data, highlighting the role of an atmosphere-based conduit for the global propagation of abrupt climate changes. The onset of the last termination in NW Patagonia is marked by glacial collapse and the expansion of rainforest trees at 17.7 ka. An apparent antiphase relationship among the polar hemispheres between 17.7-14.7 ka, might reflect the hemispheric-scale effects of a quasi-total shut down of Atlantic Meridional Overturning circulation driven by Heinrich event 1. Extreme glacial and interglacial modes in the position/strength of the westerlies at multi-millennial timescales in the southern westerlies accompany important shifts in the abundance and composition of rainforest communities during the last termination and the early Holocene. At millennial timescales, this interval is characterised by successive warming pulses interrupted by a generalized reversal in trend with cooling events starting at 14.7 and 13.4 ka. Fires between 12.9-11.5 ka, i.e. Younger Dryas Chron (YDC), led to the expansion of opportunistic rainforest species

  8. Holocene hydrological changes and human presence in NW Arabia: Insights from lipid biomarker analysis of the Tayma palaeolake sediment record

    NASA Astrophysics Data System (ADS)

    Dräger, Nadine; Schwab, Valérie F.; Plessen, Birgit; Neugebauer, Ina; Dinies, Michèle; Engel, Max; Brauer, Achim; Gleixner, Gerd

    2017-04-01

    Holocene hydrological changes in NW Arabia and their influence on human migration and settlement are scarcely studied due to the lack of suitable climate archives. In particular, mechanisms and sources of increased moisture availability as well as the onset of oasis cultivation and culture during the early Holocene humid period are still not well understood. Here, we present the first Holocene lipid biomarker record of the Arabian Peninsula from the Tayma palaeolake sediment sequence. We applied a combined approach of aquatic, terrestrial and faecal lipid biomarker and compound specific hydrogen isotope analyses, which allow tracing both hydrological and anthropogenic signals in the sediment deposits. Our investigations focused on the early Holocene annually laminated (varved) sediment section (ca. 8500 to 8000 cal. a BP) presenting a phase of maximum lake levels probably caused by increased moisture availability (Dinies et al., 2015; Engel et al., 2012). During the early Holocene high lake level phase our results show increased concentrations of long-chain n-alkanes and faecal biomarkers suggesting grassland expansion and probably human occupation. The increase in grassland during this time is further supported by results from pollen analysis (Dinies et a., 2015). However, the increase in n-alkanes and faecal biomarkers did not occur simultaneously. While the rise of n-alkane concentrations predates the onset of varved sediments by about one century, the increase in faecal biomarker coincides with the beginning of varve preservation. Moreover, comparisons with sedimentological and geochemical data (i.e. diatom layer thickness, organic carbon content, δ13Ccarbonate) suggest a coincidence of highest concentrations of faecal biomarkers and increased lake productivity. We discuss possible causes for these coincidences including prehistoric human activities as well as climate and environmental changes. This study is a contribution to the research project "CLEAR

  9. Stream, Lake, and Reservoir Management.

    PubMed

    Dai, Jingjing; Mei, Ying; Chang, Chein-Chi

    2017-10-01

    This review on stream, lake, and reservoir management covers selected 2016 publications on the focus of the following sections: Stream, lake, and reservoir management • Water quality of stream, lake, and reservoir • Reservoir operations • Models of stream, lake, and reservoir • Remediation and restoration of stream, lake, and reservoir • Biota of stream, lake, and reservoir • Climate effect of stream, lake, and reservoir.

  10. Hazardous crater lakes studied

    NASA Astrophysics Data System (ADS)

    Kusakabe, Minoru

    Crater lakes usually sit on top of volcanic conduits and act as condensers of magmatic vapor. Studies of crater lakes can therefore provide information on both deep magmatic activity and variations in the degassing state of a shallow magmatic body. The Lake Nyos gas disaster of August 1986 and a similar event in August 1984 at Lake Monoun, both in Cameroon, resulted from the accumulation of magmatic CO2 in the bottom layers of the lakes. Geochemical monitoring of crater lakes is a promising tool for forecasting not only limnic but also volcanic eruptions. Acid-mineralized waters formed by condensation of hot magmatic volatiles in crater lakes are thought to bear some resemblance to hydrothermal fluids acting in the genesis of acid-sulfate alteration and Au-Cu-Ag mineralization of volcanic-hosted precious metal deposits.

  11. Potential for Great Thrust Earthquakes in NE Colombia & NW Venezuela

    NASA Astrophysics Data System (ADS)

    Bilham, R. G.; Mencin, D.

    2013-05-01

    Sixty-five percent of the ≈19 mm/yr eastward velocity of the Caribbean Plate north of Aruba and the Guajira peninsula relative to the South American plate is accommodated by dextral slip on the Bocono Fault system in NW Venezuela at 12±1 mm/yr, the remaining ~3 mm/yr of shear apparently distributed to the NW of the fault (Perez et al., 2011). The N40E strike of the Bocono fault system, however, requires that 10.6±1 mm/yr of convergence should accompany this partitioned dextral shear, but GPS measurements reveal that less than 25% of this convergence occurs across the Venezuelan Andes. The remaining 6-8 mm of convergence is presumably accommodated by incipient subduction between the Bocono fault and a trench 300 km NW of the northern coast of Colombia. Hence NW Venezuela and NE Colombia may occasionally host great earthquakes. Our current poor understanding of the geometry of the plate interface permits the plate to be locked 300 km down-dip and possibly 600 km along-strike, and if the plate slips in 10 m ruptures it could do so every 1200 years in a M~9 earthquake. No great earthquake has occurred since 1492, since when ~4 m of potential slip has developed, but should slip occur on just 10% of the hypothesized décollement (100x150 km) it could do so now in an Mw=8.2 earthquake. In that a potential Mw>8 earthquake poses a future seismic and tsunami threat to the Caribbean it is important to examine whether great earthquakes have occurred previously near the NW Venezuela coast. It is possible that creep accommodates the entire convergence signal, since there is no suggestion from microseismicity for an abrupt locked-to-sliding transition, as, for example, signifies its location in the Himalaya. An alternative measure of future potential seismic energy release is to identify the locus and rate of present-day strain contraction. To this end, Venezuelan, Colombian and US (CU and UNAVCO) investigators are installing an array of more than a dozen continuous operating

  12. Water quality of Lake Austin and Town Lake, Austin, Texas

    SciTech Connect

    Andrews, F.L.; Wells, F.C.; Shelby, W.J.; McPherson, E.M.

    1988-01-01

    Lake Austin and Town Lake are impoundments on the Colorado River in Travis County, central Texas, and are a source of water for municipal industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Small vertical temperature variations in both lakes were attributed to shallow depths in the lakes and short retention times of water in the lakes during the summer months. The largest areal variations in dissolved oxygen generally occur in Lake Austin during the summer as a result of releases of water from below the thermocline in Lake Travis. Except for iron, manganese, and mercury, dissolved concentrations of trace elements in water collected from Lake Austin and Town Lake did not exceed the primary or secondary drinking water standards set by the US Environmental Protection Agency. Little or no effect of stormwater runoff on temperature, dissolved oxygen, or minor elements could be detected in either Lake Austin or Town Lake. Little seasonal or areal variation was noted in nitrogen concentrations in Lake Austin or Town lake. Total phosphorus concentrations generally were small in both lakes. Increased concentrations of nitrogen and phosphorus were detected after storm runoff inflow in Town Lake, but not in Lake Austin; densities of fecal-coliform bacteria increased in Lake Austin and Town Lake, but were substantially greater in Town Lake than in Lake Austin. 18 refs., 38 figs., 59 tabs.

  13. Lake trout rehabilitation in Lake Huron

    USGS Publications Warehouse

    Eshenroder, Randy L.; Payne, N. Robert; Johnson, James E.; Bowen, Charles; Ebener, Mark P.

    1995-01-01

    Efforts to restore lake trout (Salvelinus namaycush) in Lake Huron after their collapse in the 1940s were underway in the early 1970s with completion of the first round of lampricide applications in tributary streams and the stocking of several genotypes. We assess results of rehabilitation and establish a historical basis for comparison by quantifying the catch of spawning lake trout from Michigan waters in 1929-1932. Sixty-eight percent of this catch occurred in northern waters (MH-1) and most of the rest (15%) was from remote reefs in the middle of the main basin. Sea lampreys (Petromyzon marinus) increased in the early 1980s in the main basin and depressed spawning populations of lake trout. This increase was especially severe in northern waters and appeared to be associated with untreated populations in the St. Marys River. Excessive commercial fishing stemming from unresolved treaty rights also contributed to loss of spawning fish in northern Michigan waters. Seneca-strain lake trout did not appear to be attacked by sea lampreys until they reached a size > 532 mm. At sizes > 632 mm, Seneca trout were 40-fold more abundant than the Marquette strain in matched-planting experiments. Natural reproduction past the fry stage has occurred in Thunder Bay and South Bay, but prospects for self-sustaining populations of lake trout in the main basin are poor because sea lampreys are too abundant, only one side of the basin is stocked, and stocking is deferred to allow commercial gillnetting in areas where most of the spawning occurred historically. Backcross lake trout, a lake trout x splake (s. Fontinalis x s. Namaycush) hybrid, did not reproduce in Georgian Bay, but this genotype is being replaced with pure-strain lake trout, whose early performance appears promising.

  14. Extensional Tectonics Evidenced in Recent Sediments of Lake Van, Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Sengul, M. Alper; Koral, Hayrettin; Elmas, M. Ali

    2016-04-01

    The Lake Van region is characterized by NE-SW trending faults with a left-lateral normal-slip component, NW-SE trending faults with a right-lateral normal-slip component and E-W trending reverse/thrust-slip faults, suggesting a N-S trending compressional stress orientation. Tectonic effects in the region continue to be manifested by recent seismicity as in the earthquake of October 23, 2011 (Mw=7.1). Although this earthquake has not produced many earthquake-related surface deformation, evidences of recent tectonics are rather extensive in the Quaternary sediments surrounding the lake. Therefore ages of sediments are important in determining the timing of tectonic activity. Optically stimulated luminescence (OSL) method was used to determine the age of lake sediments to the north of the lake. Also, shells of gastropods available in the sediments are dated by C14. Ages suggest that to the NE of Lake Van youngest activity on the NW-SE trending Erciş Fault with right-lateral normal-slip component is to be 34 ka. Activity on other normal faults in the same area is dated between 10-14 ka and 20 ka. Also, samewhat to the south of this region in vicinity of the Canik area, reverse faulting is dated to be younger than 40 ka. All ages indicate the region has been affected during the Pleistocene locally by an extensional regime contemporaneously with the contractional regime. The evidence of a one meter dip-slip displacement measured on a fault plane in a quarry supports the view of local extension in the NE sector of the lake. Key Words: Lake Van, OSL dating, neotectonics, active tectonics

  15. Metaheuristic Technique for Finding Earthquake Locations in NW Himalayan Region

    NASA Astrophysics Data System (ADS)

    Yadav, Anupam; Deep, Kusum; Kumar, Sushil; Sushil, Rama

    In this article, we have used a new metaheuristic technique particle swarm optimization (PSO) for development of the earthquake location models. Two models of different crustal structures has been taken based on the arbitrary tardiness structure that defines the heterogeneity of the earth’s crust. The problem of earthquake location is modeled as a least square function of travel times and solved by using the randomized search algorithm PSO. We have solved the problem by using an advanced version of PSOs. A real life data of earthquake in the NW Himalayan region has been taken for testing these developed models. The new locations are better than the existing results.

  16. 14. Stairs in far NW corner of the North Section, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Stairs in far NW corner of the North Section, as viewed from atop pier. This photo, along with phot WA-116-E-1, are the only photographs of the North Section of Drydock 3 that were approved by the U.S. Navy for inclusion in this HAER report. The brick building in center distance is the Building 59, the Pattern Shop, which has been documented in the HAER report No. WA-116-A. - Puget Sound Naval Shipyard, Drydock No. 3, Farragut Avenue, Bremerton, Kitsap County, WA

  17. Origin of lacustrine carbonate-dominated clinoforms in the lower- Permian Lucaogou low-order cycle, southern Bogda Mountains, NW China

    NASA Astrophysics Data System (ADS)

    Lu, Yiran

    Lacustrine carbonate clinoforms deposit can reflect ancient lake condition like paleoclimate and lake type. Complex lithofacies of a carbonate-dominated clinoform package in lower Permian Lucaogou low order cycle, Bogda Mountains, NW China, provide clues on clinoform-forming processes in a half-graben lake. The clinoform package is 5.2 m thick, prograding from S to N for 200 m with a maximum 15o dip angle, and spans 4 km laterally. A clinoform consists of a lower siliciclastic-rich and an upper carbonate-rich beds, forming a clinoform cycle. Results of petrographic study of 30 thin sections suggest that the clinoform package is composed of mixed siliciclasticcarbonate rocks. Carbonate-rich bed is composed of diagenetically-altered lithic packstone and wackestone, and siliciclastic-rich clinoform of micritic sandstone. The foundation rock is mainly microbial boundstone, indicating a shallow littoral environment. The carbonate-rich beds mainly consist of coarse peloids, rip-up intraclasts, aggregate grains, and volcanic lithics. The siliciclastic-rich clinoform is rich in coarse volcanic lithics. Both types of clinoforms contain abundant current laminations, indicating frequent strong current activities. The lack of evidence of unidirectional current flow suggests that the carbonate-dominated clinoform package was probably primarily formed by wave and longshore current processes. Unlike grains in wave-built terrace in the Glenns Ferry Formation (Swirydczuk et al., 1979, 1980), few ooids were observed in the studied strata, which do not have local sediments as nucleus and are often broken. This indicates that the wave was not facing the lake margin directly but was more oblique to the lake margin. The carbonate-dominated clinoform package is thus interpreted as a bar or spit, controlled primarily by lake shoreline morphology and strong wave and current activities. The shift between carbonate and siliciclastic rich clinoform beds within a clinoform cycle suggests high

  18. Backscatter from ice growing on shallow tundra lakes near Barrow, Alaska, winter 1991-1992

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Wakabayashi, H.; Weeks, W. F.; Morris, K.

    1993-01-01

    The timing of freeze-up and break-up of Arctic lake ice is a potentially useful environmental indicator that could be monitored using SAR. In order to do this, it is important to understand how the properties and structure of the ice during its growth and decay affect radar backscatter and thus lake ice SAR signatures. The availability of radiometrically and geometrically calibrated digital SAR data time series from the Alaska SAR Facility has made it possible for the first time to quantify lake ice backscatter intensity (sigma(sup o)) variations. This has been done for ice growing on shallow tundra lakes near Barrow, NW Alaska, from initial growth in September 1991 until thawing and decay in June 1992. Field and laboratory observations and measurements of the lake ice were made in late April 1992. The field investigations of the coastal lakes near Barrow confirmed previous findings that, (1) ice frozen to the lake bottom had a dark signature in SAR images, indicating weak backscatter, while, (2) ice that was floating had a bright signature, indicating strong backscatter. At all sites, regardless of whether the ice was grounded or floating, there was a layer of clear, inclusion-free ice overlaying a layer of ice with dense concentrations of vertically oriented tubular bubbles. At some sites, there was a third layer of porous, snow-ice overlaying the clear ice.

  19. Stage fluctuations of Wisconsin lakes

    USGS Publications Warehouse

    House, Leo B.

    1985-01-01

    This report describes lake-stage fluctuations of 83 gaged lakes in Wisconsin and presents techniques for estimating stage fluctuation at ungaged lakes. Included are stage information at 83 lakes and stage-frequency data for 32 of these lakes that had sufficient record for analysis. Lakes are classified by a hydrologic-topographic lake classification scheme as ground-water flowthrough (GWF) lakes, surface-water drainage (SWD) lakes, and surface-water flow-through (SWF) lakes. Lakes within the same class were found to have similar water-level fluctuations. The lake-stage records indicate that most annual maximums occur during the months of May and June for all three classes. Annual minimum lake levels generally occur in September for surface-water drainage lakes, in March for surface-water flowthrough lakes, and in November for ground-water flow-through lakes. Data for each lake include location, period of water-level record, hydrologic classification, drainage area, surface area, lake volume, maximum depth, long-term mean stage and its standard deviation, maximum and minimum observed lake stage, and the average annual lake-stage fluctuation.

  20. Salting our freshwater lakes.

    PubMed

    Dugan, Hilary A; Bartlett, Sarah L; Burke, Samantha M; Doubek, Jonathan P; Krivak-Tetley, Flora E; Skaff, Nicholas K; Summers, Jamie C; Farrell, Kaitlin J; McCullough, Ian M; Morales-Williams, Ana M; Roberts, Derek C; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C; Weathers, Kathleen C

    2017-04-10

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L(-1)), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.

  1. Lake Balkhash, Kazakhstan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of crescent-shaped Lake Balkhash was taken by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on April 27, 2000. Lake Balkhash is located in eastern Kazakhstan, north of the Tian-Shan mountains. The Ili River flows into the western end of the lake, filling it with bright sediment. This sediment highlights the difference between the freshwater western side of the lake and the saline eastern side. A sandbar prevents mixing between the lake's two sections.Other features in this image include Lake Sayram in the lower right (southeast) corner, which is surrounded by the Borohoro Shan mountain range. At center right, just north of the Borohoro Shan, are lakes Sasykkol (left) and Alakol (right). The Karatal River flows northward through an arid and sandy landscape into the center of Lake Balkhash. The full-size image compares the region on April 27th image with one from the 18th. In that time sediments in lakes Balkhash and Sasykol increased noticeably, probably due to snowmelt-note the decrease in snowcover on the region's mountains. Also, the ice on Lake Sayram melted. These images were retrieved by the SeaWiFS high-resolution ground station in Mongolia, which recently began sending data to Goddard Space Flight Center. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  2. Salting our freshwater lakes

    PubMed Central

    Bartlett, Sarah L.; Burke, Samantha M.; Doubek, Jonathan P.; Krivak-Tetley, Flora E.; Skaff, Nicholas K.; Summers, Jamie C.; Farrell, Kaitlin J.; McCullough, Ian M.; Morales-Williams, Ana M.; Roberts, Derek C.; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C.; Weathers, Kathleen C.

    2017-01-01

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L−1), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue. PMID:28396392

  3. Brittle-fault deformation history in the NW Himalaya (Himachal Pradesh, India)

    NASA Astrophysics Data System (ADS)

    Hintersberger, E.; Decker, K.; Thiede, R.; Strecker, M.

    2009-04-01

    The Himalayan mountain belt and the Tibetan Plateau are the manifestations of intense crustal shortening and uplift along the southern margin of Eurasia associated with the India-Eurasia collision. While crustal shortening has been focused at lower elevations until the present day along the southern boundary of the Lesser Himalaya and the Siwalik ranges, several generations of both, orogen-parallel and orogen-perpendicular extensional structures have developed. These structures characterize the higher-elevation regions within the Higher and Tethyan Himalaya, suggesting syntectonic extension. In the NW Himalaya (India), extending from the deeply cut gorges of the Sutlej and Spiti rivers to the Garhwal Himalaya, closely spaced young normal faults, focal mechanisms of earthquakes with magnitudes between 5.2 and 6.8, and regional GPS measurements reveal ongoing E-W extension. Surprisingly, and in contrast to other extensional features observed in the Himalaya, this direction is neither parallel nor perpendicular to the NE-SW regional shortening direction. Here, we present new data obtained from structural geological mapping, fault kinematic analysis of hundreds of brittle faults, and remote sensing spanning the area between the Tso Morari Lake in the Tibetan Himalaya in the north and the mountain front in the Garhwal Himalaya in the south (30°-33°N/77°-79°E). In addition, we integrated published data on extensional phenomena in this region of the Himalaya. In the Garhwal Himalaya and the Sutlej-Spiti region, we collected and analyzed outcrop-scale brittle fault-planes with displacements of up to several cm. To analyze fault kinematic data (strike and dip of the fault, slip direction and sense of slip) for these micro-faults, we calculated strain axes for approx. 100 outcrop locations using the TectonicsFP program. This data set, as well as field observations on crosscutting relationships, mineralization of fault planes, and correlations with deformation structures

  4. New data on the Lateglacial period of SW Europe: a high resolution multiproxy record from Laguna de la Roya (NW Iberia)

    NASA Astrophysics Data System (ADS)

    Muñoz Sobrino, C.; Heiri, O.; Hazekamp, M.; van der Velden, D.; Kirilova, E. P.; García-Moreiras, I.; Lotter, A. F.

    2013-11-01

    High-resolution multiproxy analyses were performed on a 128 cm section of organic sediments accumulated in a small mountain lake in NW Iberia (Laguna de la Roya, 1608 m asl). The pollen stratigraphy together with radiocarbon dating provided the basis for a chronology ranging from 15,600 to 10,500 cal yr BP. Chironomid-inferred July air temperatures suggest a temperature range from 7 to 13 °C, also evidencing two well-established cold periods which may be equivalent to the INTIMATE stages GS-2a and GS-1. Furthermore, a number of short cold events (with summer temperatures dropping about 0.5-1 °C) appear intercalated within the Lateglacial Interstadial (possibly equivalent to the INTIMATE cold events GI-1d, GI-1c2 and GI-1b) and the early Holocene (possibly equivalent to the 11.2 k event). The temperature variations predicted by our reconstruction allow explaining the changes in local conditions and productivity of the lake inferred from the biological record of the same sediment core. Furthermore, they also agree with the local and regional vegetation dynamics, and the main oscillations deduced for the vegetation belts. Based on its chronology our multiproxy record indicates a similar temperature development in NW Iberia as inferred by the Greenland δ18O record, the marine deep-sea records off the Atlantic Iberian Margin, and other chironomid-based Lateglacial temperature reconstructions from Europe. Nevertheless, the impact of most of the less intense Lateglacial/early Holocene cold events in NW Iberia was most probably limited to very sensitive sites that were very close to ecotonal situations. Particularly, our new pollen record indicates that they were represented as three minor environmental crises occurring during the Lateglacial Interestadial in this area. The Older Dryas event (in our usage corresponding to the Aegelsee Oscillation in Central Europe and event GI-1d in central Greenland) has previously been described in this region, but its age and

  5. View of Lake Sabrina Dam and Lake Sabrina from east ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Lake Sabrina Dam and Lake Sabrina from east ridge showing spillway at photo center, view southwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  6. In-lake Modeling Recommendation Report for Lake Champlain TMDL

    EPA Pesticide Factsheets

    This report describes the recommended modeling approach for the in-lake modeling component of the Lake Champlain TMDL project. The report was prepared by Tetra Tech, with input from the Lake Champlain modeling workgroup. (TetraTech, 2012b)

  7. 9. GRANT LAKE AND MONO LAKE IN DISTANCE, LOOKING NORTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. GRANT LAKE AND MONO LAKE IN DISTANCE, LOOKING NORTHEAST - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  8. Ocean - ice sheet interaction along the NW European margin during the last glacial phases

    NASA Astrophysics Data System (ADS)

    Becker, L. W. M.; Sejrup, H. P.; Haflidason, H.; Hjelstuen, B. O. B.

    2015-12-01

    The NW European continental margin was repeatedly covered by shelf edge glaciations during the last glacial cycles. Here, we present a compilation of new and previously published data from a SW to NE transect of 8 sediment cores raised along the upper continental slope. This study aims to investigate the interaction between sea surface conditions and the variability seen in the British Irish Ice Sheet (BIIS) and the Fennoscandian Ice Sheet (FIS) during the last 13-40 ka BP. Ice Rafted Debris (IRD) counts, IRD flux data, grain size data, the content of the polar planktonic foraminifera Neogloboquadrina pachyderma (sin) and ∂18O measurements were compiled and combined with new Bayesian age models. From 40-24.5 ka BP the build up and consecutive confluence of the BIIS and the FIS are reflected in sediment composition and flux data. Pulses of large quantities of fine material to the southern part of the transect suggest riverine BIIS related influx. The sediment composition in cores close to the Norwegian channel indicates that the Norwegian Channel Ice Stream (NCIS) was only active between 24.5-18.5 ka BP during the last glacial stage. The planktonic foraminifera data during this period strongly suggests a dependence of NCIS extent variability and pulses in warm Atlantic water entering the Nordic Seas. In the northernmost cores rapidly deposited, laminated sediments and ∂18O spikes in planktonic foraminifera dated to 18.5 ka BP were interpreted as meltwater plume deposits. This may reflect NCIS retreat allowing BIIS and FIS to unzip and route ice dammed lake- and meltwater to the margin. In conclusion, the investigation suggests a close co-variation in extent of marine based parts of the BIIS, the FIS and ocean circulation while demonstrating the strong influence of the local glacial history on standard open marine proxies. This suggests that tuning chronologies of single marine records to ice cores in some regions might be more challenging than previously

  9. Numerical modeling of Drangajökull Ice Cap, NW Iceland

    NASA Astrophysics Data System (ADS)

    Anderson, Leif S.; Jarosch, Alexander H.; Flowers, Gwenn E.; Aðalgeirsdóttir, Guðfinna; Magnússon, Eyjólfur; Pálsson, Finnur; Muñoz-Cobo Belart, Joaquín; Þorsteinsson, Þorsteinn; Jóhannesson, Tómas; Sigurðsson, Oddur; Harning, David; Miller, Gifford H.; Geirsdóttir, Áslaug

    2016-04-01

    Over the past century the Arctic has warmed twice as fast as the global average. This discrepancy is likely due to feedbacks inherent to the Arctic climate system. These Arctic climate feedbacks are currently poorly quantified, but are essential to future climate predictions based on global circulation modeling. Constraining the magnitude and timing of past Arctic climate changes allows us to test climate feedback parameterizations at different times with different boundary conditions. Because Holocene Arctic summer temperature changes have been largest in the North Atlantic (Kaufman et al., 2004) we focus on constraining the paleoclimate of Iceland. Glaciers are highly sensitive to changes in temperature and precipitation amount. This sensitivity allows for the estimation of paleoclimate using glacier models, modern glacier mass balance data, and past glacier extents. We apply our model to the Drangajökull ice cap (~150 sq. km) in NW Iceland. Our numerical model is resolved in two-dimensions, conserves mass, and applies the shallow-ice-approximation. The bed DEM used in the model runs was constructed from radio echo data surveyed in spring 2014. We constrain the modern surface mass balance of Drangajökull using: 1) ablation and accumulation stakes; 2) ice surface digital elevation models (DEMs) from satellite, airborne LiDAR, and aerial photographs; and 3) full-stokes model-derived vertical ice velocities. The modeled vertical ice velocities and ice surface DEMs are combined to estimate past surface mass balance. We constrain Holocene glacier geometries using moraines and trimlines (e.g., Brynjolfsson, etal, 2014), proglacial-lake cores, and radiocarbon-dated dead vegetation emerging from under the modern glacier. We present a sensitivity analysis of the model to changes in parameters and show the effect of step changes of temperature and precipitation on glacier extent. Our results are placed in context with local lacustrine and marine climate proxies as well

  10. Radon as an earthquake precursor in NW Himalayas, India

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Singh, Surinder; Singh Bajwa, Bikramjit; Mahajan, Sandeep; Dhar, Sunil; Walia, Vivek

    2010-05-01

    The continuous soil gas radon and daily monitoring of radon concentration in water is carried out at Amritsar (Punjab), Kangra and Chamba Valleys of NW Himalayas India to study the correlation of radon anomalies in relation to seismic activities in the region. In this study, radon monitoring in soil was carried out by using barasol probe manufactured by Algade France whereas the radon content in water was recorded using RAD7 radon monitoring system of Durridge Company USA. The radon anomalies observed in the region have been correlated with the seismic events of M ≥ 2 recorded in NW Himalayas by Wadia Institute of Himalayas Geology Dehradoon and Indian Meteorological Department, New Delhi. The effect of meteorological parameters viz. temperature, pressure, wind velocity and rainfall on radon emission has been studied. The correlation coefficient between radon and meteorological parameters has been evaluated. The equation for the correction of these correlations to obtain a corrected radon concentration that shows less variability is derived. Empirical equations between earthquake magnitude, epicentral distance and precursor time have been examined and respective constants were determined

  11. 2016 Lake Michigan Lake Trout Working Group Report

    USGS Publications Warehouse

    Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

    2017-01-01

    This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

  12. Origins of rainbow smelt in Lake Ontario

    USGS Publications Warehouse

    Bergstedt, Roger A.

    1983-01-01

    The first rainbow smelt (Osmerus mordax) to enter Lake Ontario were probably migrants from an anadromous strain introduced into New York's Finger Lakes. Since the upper Great Lakes were originally stocked with a landlocked strain from Green Lake, Maine, subsequent migration to Lake Ontario from Lake Erie makes Lake Ontario unique among the Great Lakes in probably having received introductions from two distinct populations.

  13. Hydrology of Indiana lakes

    USGS Publications Warehouse

    Perrey, Joseph Irving; Corbett, Don Melvin

    1956-01-01

    The stabilization of lake levels often requires the construction of outlet control structures. A detailed study of past lake-level elevations and other hydologic date is necessary to establish a level that can be maintained and to determine the means necessary for maintaining the established level. Detailed lake-level records for 28 lakes are included in the report, and records for over 100 other lakes data are available in the U.S. Geological Survey Office, Indianapolis, Ind. Evaporation data from the four Class A evaporation station of the U. S. Weather Bureau have been compiled in this report. A table showing the established legal lake level and related data is included.

  14. Mono Lake, California

    NASA Image and Video Library

    2017-03-24

    In eastern California, along the western edge of the Great Basin, sits Mono Lake. This is a salty remnant of a wetter era. Estimates are that the lake existed for at least 760,000 years. Now surrounded by mountain ranges, however, Mono Lake has no outlet; water entering the lake can only evaporate away, so Mono Lake is saltier than the ocean. South of the lake appear some of the geologic features known as Mono Craters. Geologists estimate that the Mono Craters last erupted about 650 years ago. The image was acquired July 7, 2016, covers an area of 22.6 by 34 km, and is located at 37.9 degrees north, 119 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA21518

  15. Lake Enriquillo, Dominican Republic

    NASA Image and Video Library

    2017-08-15

    Lake Enriquillo is a hypersaline lake in the Dominican Republic. In 2004, the lake covered an area of 164 square kilometers; by 2011, it had doubled in size and grown to 350 km2, inundating farmland and homes. Various reasons for the flooding include increases in rainfall; increase of sediments going into the lake, raising the lakebed; and milder temperatures, reducing surface evaporation. The lake is home to the largest population of American crocodiles in the Caribbean. The images were acquired October 26, 2003 and June 10, 2017, cover an area of 22.7 by 45.4 km, and are located at 18.5 degrees north, 71.6 degrees west. An image of Lake Enriquillo taken in 2003 is available at https://photojournal.jpl.nasa.gov/catalog/PIA21815

  16. Speciation in ancient lakes.

    PubMed

    Martens, K

    1997-05-01

    About a dozen lakes in the world are up to three orders of magnitude older than most others. Lakes Tanganyika (East Africa) and Baikal (Siberia) have probably existed in some form for 12-20 million years, maybe more. Such lakes can have different origins, sizes, shapes, depths and limnologies, but, in contrast to short-lived (mostly post-glacial) lakes, they have exceptionally high faunal diversity and levels of endemicity. A multitude of and processes accounting for these explosive radiations have recently been documented, most of them based on particular groups in certain lakes, but comparative research can detect repeated patterns. No special speciafion mechanism, exclusive to ancient lakes has been demonstrated, although cases of ultra-rapid speciation have been documented. Extant diversity results not by simple accumulation, but by a complex process of immigration, speciation and extinction.

  17. David Morrison on Lake Vostok

    NASA Image and Video Library

    Dr. David Morrison discusses the implications of research possibilities at Lake Vostok, one of the largest subglacial lakes located over two miles beneath the ice in Antarctica. The lake has been c...

  18. Aquatic biogeochemistry: Cleaner Chinese lakes

    NASA Astrophysics Data System (ADS)

    Corman, Jessica

    2017-07-01

    Phosphorus loading can cause eutrophication of lakes. Analyses of lake chemistry in China reveal that policies have led to lower phosphorus levels overall, but increasing trends in some lakes suggest that expanded policies may be needed.

  19. Lake Mead, NV

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead.

  20. Stacked uppermost mantle layers within the Slave craton of NW Canada as defined by anisotropic seismic discontinuities

    NASA Astrophysics Data System (ADS)

    Snyder, David B.

    2008-08-01

    A 20-station seismic array in NW Canada recorded 336 teleseismic events with distribution in back azimuth and epicentral distance sufficient to characterize uppermost mantle discontinuities between depths typical of the Mohorovicic and Lehman discontinuities. Following wavefield decomposition, groups of seismograms were source-normalized through simultaneous deconvolution to estimate the near-receiver impulse response and thus detect major discontinuities beneath each seismic station. Stations within the Lac de Gras kimberlite field display an unusually strong negative impulse on the radial component within the NW quadrant and two moderate impulses on the transverse component. Forward modeling of these impulses suggests a mantle layer dipping at 22° to the southeast with a mildly anisotropic (2%) upper discontinuity at 120-135 km depth and another mildly anisotropic (2%) discontinuity at about 170 km depth. Superimposed on these layers is another, stronger anisotropic (4%) layer between 110 and 180 km depths that dips to the west. Stations outside of the Lac de Gras field, but within the southeastern Slave craton, display more numerous, but weaker, impulses. The most prominent of these occurs at about 150 km depth on the transverse component and has opposite polarity to that observed farther north. The prominent negative impulse observed on the radial component is interpreted to arise from structural-preferred orientation in the form of a stockwork of wehrlite dykes beneath the Lac de Gras field. Interpretation of the other layers in the context of known surface geology as well as xenolith petrology and garnet geochemistry of diamondiferous kimberlites favors previous suggestions that they represent 4000-2900 Ma depleted harzburgite and eclogite layers underthrust from the northwest at 2600 or 1880 Ma. The layer beneath the SE Slave craton has a similar, but distinct, tectonic history of NW-verging underthrusting associated with the 2635-2615 Ma Defeat Suite of

  1. Great Lakes Literacy Principles

    NASA Astrophysics Data System (ADS)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

    Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

  2. Structural Evolution of the Incipient Okavango Rift Zone, NW Botswana

    NASA Astrophysics Data System (ADS)

    Atekwana, E. A.; Kinabo, B. D.; Modisi, M. P.; Hogan, J. P.; Wheaton, D. D.

    2005-05-01

    Studies of the East African Rift System (EARS) and other continental rifts have significantly improved our understanding of rifting processes; however, we particularly lack studies of the embryonic stages of rift creation. The Okavango Rift Zone (ORZ), NW Botswana is one of few places worldwide where one can study the early stages of continental extension prior to the accumulation of significant amounts of sediments, volcanism, and multiphase deformation that obscure the investigation of these early time processes in more evolved continental rift zones. In this study, gravity and aeromagnetic data have been used to examine the initiation and development of the nascent ORZ. The Okavango basin in NW Botswana is located at the southern tip of the southwestern branch of the EARS. The rift is hosted within the Proterozoic fold and thrust belt of the Ghanzi-Chobe formation. Our objectives include (1) assessing the role of pre-existing structures on the development of rift faults and basin architecture, (2) Examining fault linkage patterns and boarder fault development, and (3) determining the shallow subsurface basin geometry. Aeromagnetic data from the ORZ suggest two main structural trends: 1) northeast-southwest (030- 070o) and 2) northwest - southeast (290 - 320o). The 030- 070o structures occur within the rift zone and throughout the surrounding basement. They form the main bounding fault system of this incipient rift. The NE - SW orientations of rift faults mirror the fold axes and foliation of the basement rocks, suggesting that the basement fabric played an important role in localizing the development of faults within the stress regime present during the initiation of this rift. Additionally, the greatest throw (~400- ~700 m) occurs along the Kunyere (NW dipping) and Tsau faults (SE dipping), defining a full graben as observed on gravity models. This differs from the half-graben model typical of most continental rift zones. Thus, it appears the basin geometry was

  3. Glacial legacy control on landslide mobility in NW Washington

    NASA Astrophysics Data System (ADS)

    Perkins, J. P.; Schmidt, K. M.; Reid, M. E.; Slaughter, S.

    2016-12-01

    The occurrence of the deadly SR 530 landslide along the North Fork Stillaguamish river valley in 2014 spurred a heightened interest in understanding landslide hazards in NW Washington, and recent work (e.g., Haugerud et al. 2014; LaHusen et al., 2016) shows that high-volume, long-runout landslides such as the SR 530 slide are a common feature in this valley's geologic past. Adjacent valleys do not show this same pattern, however, and it is presently unclear what governs the mobility and spatial distribution of the longest runout slides in the region. Given that landslide runout length may depend strongly upon both lithology and material properties of the hillslope before failure (e.g., Iverson et al., 2000; 2015), we use LiDAR data for NW Washington to characterize the mobility of 150 landslides across a range of lithologic and geomorphic settings. The highest mobility landslides, as characterized by the ratio of runout length, L, to fall height, H, uniformly occur in terraces of Pleistocene glacial outwash and ice-marginal (e.g., lacustrine) deposits that spatially cluster with the maximum extent of the Cordilleran ice sheet (median L/H of 6, maximum L/H of 12). Knickpoints along longitudinal profiles of major drainages project from bedrock-dominated uplands to downstream glacial drift terrace surfaces and suggest rivers along the Western Cascades are still slowly responding to the retreat of the Cordilleran ice sheet. Downstream of knickpoints, landslides appear to cluster along terraced valley walls that exceed a threshold relief. However, a large range in runout length exists for high H values within drift terraces, indicating that additional processes are likely influencing runout distances. We hypothesize that material heterogeneity between deposits (e.g., the relative abundance and stratigraphic sequencing of lacustrine sediments and high porosity glacial outwash deposits) may exert a fundamental control on potential mobility. Together these findings suggest

  4. Lakes, Lagerstaetten, and Evolution

    NASA Astrophysics Data System (ADS)

    Kordesch, E. G.; Park, L. E.

    2001-12-01

    The diversity of terrestrial systems is estimated to be greater than in the marine realm. However no hard data yet exists to substantiate this claim. Ancient lacustrine deposits may preserve an exceptionally diverse fossil fauna and aid in determining continental faunal diversities. Fossils preserved in lake deposits, especially those with exceptional preservation (i.e. Konservat Lagerstaetten), may represent a dependable method for determining species diversity changes in the terrestrial environment because of their faunal completeness. Important Konservat Lagerstaetten, such as the Green River Formation (US) and Messel (Germany), both Eocene in age, are found in lake sediments and show a remarkable faunal diversity for both vertebrates and invertebrates. To date information from nearly 25 lake lagerstaetten derived from different types of lake basins from the Carboniferous to the Miocene have been collected and described. Carboniferous sites derive from the cyclothems of Midcontinent of the US while many Cenozoic sites have been described from North and South America as well as Europe and Australia. Asian sites contain fossils from the Mesozoic and Cenozoic. With this data, insight into the evolutionary processes associated with lake systems can be examined. Do lakes act as unique evolutionary crucibles in contrast to marine systems? The speciation of cichlid fishes in present-day African lakes appears to be very high and is attributed to the diversity of environments found in large rift lakes. Is this true of all ancient lakes or just large rift lakes? The longevity of a lake system may be an important factor in allowing speciation and evolutionary processes to occur; marine systems are limited only in the existence of environments as controlled by tectonics and sea level changes, on the order of tens of millions of years. Rift lakes are normally the longest lived in the millions of years. Perhaps there are only certain types of lakes in which speciation of

  5. Lake level and climate records of the last 90 ka from the Northern Basin of Lake Van, eastern Turkey

    NASA Astrophysics Data System (ADS)

    Çağatay, M. N.; Öğretmen, N.; Damcı, E.; Stockhecke, M.; Sancar, Ü.; Eriş, K. K.; Özeren, S.

    2014-11-01

    Sedimentary, geochemical and mineralogical analyses of the ICDP cores recovered from the Northern Basin (NB) of Lake Van provide evidence of lake level and climatic changes related to orbital and North Atlantic climate system over the last 90 ka. High lake levels are generally observed during the interglacial and interstadial periods, which are marked by deposition of varved sediments with high total organic carbon (TOC), total inorganic carbon (TIC), low detrital influx (high Ca/F) and high δ18O and δ13C values of authigenic carbonate. During the glacial and stadial periods of 71-58 ka BP (Marine Isotope Stage 4, MIS4) and end of last glaciation-deglaciation (30-14.5 ka BP; MIS3) relatively low lake levels prevailed, and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates. Millennial-scale variability of the proxies during 60-30 ka BP (MIS3 is correlated with the Dansgaard-Oeschger (D-O)) and Holocene abrupt climate events in the Atlantic. These events are characterized by laminated sediments, with high TOC, TIC, Ca/Fe, δ18O and δ13C values. The Lake Van NB records correlate well in the region with the climate records from the lakes Zeribar and Urmia in Iran and the Sofular Cave in NW Anatolia, but are in general in anti-phase to those from the Dead Sea Basin (Lake Lisan) in the Levant. The relatively higher δ18O values (0 to -0.4‰) for the interglacial and interstadial periods in the Lake Van NB section are due to the higher temperature and seasonality of precipitation and higher evaporation, whereas the lower values (-0.8 to -2‰) during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation. The high δ18O values (up to 4.2‰) during the Younger Dryas, together with the presence of dolomite and low TOC contents, supports evaporative conditions and low lake level. A gradual decrease in the δ18O values from an

  6. Hydrogeochemical processes and chemical characteristics around Sahand Mountain, NW Iran

    NASA Astrophysics Data System (ADS)

    Pazand, Kaveh; Hezarkhani, Ardeshir

    2013-06-01

    The chemical analysis of 21 water wells in Sahand area, NW of Iran has been evaluated to determine the hydrogeochemical processes and ion, heavy and trace metal concentration background in the region. The dominated hydrochemical types are Ca-Mg-HCO3, Ca-SO4 and Na-Cl that vary in different group sample. The pH and Eh of the groundwater in the study area indicating an acidic to alkaline nature of the samples in group II, acidic nature in group I and neutral in group III. Also in Group III than Group I and II, the oxidizing condition is dominant, while in the other groups relative reducing conditions prevail. Due to Cu and other metal mineralization in I and II site, Cu, As, Au and other metal concentration in this water groups is higher than group III.

  7. 51. (Credit JTL) Interior view (looking NW) of new pumping ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. (Credit JTL) Interior view (looking NW) of new pumping room built in 1921. In the right foreground is #1 low service pump built in 1897. Installed at McNeil in 1898, it was not moved during the building of this room in 1921. Beyond is a 5 mgd capacity Worthington-Snow cross-compound, duplex crank-and-fly-wheel engine built in 1920. Behind the worthington is an 8 mgd Allis-Chalmers engine of the same configuration. it was built in 1911, but not installed at McNeil until 1927. Both engines have condensers. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  8. Resolution experiments for NW Pacific subduction zone tomography

    NASA Technical Reports Server (NTRS)

    Spakman, Wim; Van Der Hilst, Rob; Wortel, Rinus; Stein, Seth

    1989-01-01

    Results are reported from an investigation of the resolving power of ISC/NEIC P travel-time data in tomographic inversions for the geometry of the subduction zones in the NW Pacific. From thermal models for the Kurile, Janan, Izu-Bonin, Mariana, and Ryukyu slabs, three-dimensional synthetic velocity anomalies for subducting slabs are generated and projected onto a cell model for the uppermost 1400 km of the mantle. These synthetic models are used to compute synthetic delay times for ray paths corresponding to the source and receiver locations used for the actual data, add Gaussian noise, invert the synthetic data, and compare the resulting velocity structure to the initial synthetic models. This comparison is illustrated for sections through the Kuriles and the Mariana arcs. A variety of resolution artifacts are observed, which in many cases resemble features visible in the tomographic results obtained from inverting the actual ISC/NEIC data.

  9. Atypical coastal environmental change during Copper Age - Bronze Age transition (Rio de Moinhos, NW Portugal) - preliminary results

    NASA Astrophysics Data System (ADS)

    Granja, Helena; Danielsen, Randi

    2015-04-01

    The research is part of an ongoing project of geo-archaeology from Rio de Moinhos beach (Esposende, NW Portugal), where an extensive area of dark sedimentary outcrops and a large amount of ceramic remains from a Roman shipwreck are present. The dark sedimentary deposit, presenting tree stumps and roots in life position, partially covers a rocky platform that extends seawards. Over the platform, that presents many pits of sea urchins (infralittoral environment) as well as salt pans (supratidal environment), a marine rusty conglomerate is present in some places. Several hand gauge cores were extracted in the sedimentary deposit whose maximum depth do not exceed 50cm. Samples from cores and outcrops were analysed for grain size, mineralogical composition, pollen and diatom content and radiocarbon dated. This work concerns sediment size analysis, dating and pollen. Tree stumps and roots of Alnus glutinosa dated 6310-6220 cal BP are in the base of the sedimentary sequence that presents a gradual passage from very fine sands to clayey silts, all of them organic and very poorly sorted. Pollen analysis revealed an initial wetland habitat containing Alnus, inundated ca 5645-5585 cal BP due to rising sea level at the time. A brackish lagoon formed at the site presumably protected by a clastic barrier seaward. Similar formations of lagoons are detected all along the Portuguese coast, typically disappearing with time due to sand infilling. In this case, however, the brackish lagoon turned into a fresh water lake ca 4485-4440 cal BP. This may have been a natural development caused by permanent closing of the clastic barrier but human interference cannot be excluded as anthropic activity was detected since formation of the lagoon. The lake seems to have filled in with sand at some point in time subsequent to ca 3750-3725 cal BP, the date of the top lake sediment. However, shipwreck vestiges from the Roman Period presently dispersed over the lake sediment, suggests a later date

  10. An investigation of the origin of Rock City and cause of piping problems at Mountain Lake, Giles County, Virginia

    NASA Astrophysics Data System (ADS)

    Atallah, Nidal Walid

    Mountain Lake is one of only two natural lakes in the state of Virginia. The lake's origin has been attributed to either a natural solution-collapse basin, or to a landslide damming the valley of northwesterly flowing Pond Drain, or to a NW-SE trending fracture lineation. The lake is located within the breached northwest limb of a gently plunging anticline, a part of the larger Valley and Ridge physiographic province. In recent years, the lake drained almost completely, exposing the lake bottom and revealing the presence of four sinkhole-like depressions, containing piping holes at their sides and bottoms, at the northeastern and northwestern margins of the lake. This study focuses on the most likely origin of large sandstone blocks present at the northern end of the lake in an area locally referred to as "Rock City", including mapping of the block locations and analyzing the mode and extent of displacement that they have undergone. An additional objective is to investigate the piping potential of the lake-bottom sediment and its role in seepage out of the lake basin causing lake-level fluctuations. Mapping of Rock City was conducted by taking GPS readings at the corners of the rock blocks and using ArcMap Software. Investigations of the displacement mode of the rock blocks was done by comparing the measured orientations of principal discontinuity sets, forming the rock-block boundaries, with discontinuity orientations of undisturbed outcrops within the headscarp, using stereonet analysis. Grain size analysis, Atterberg limits, and a compaction-mold permeameter test were used to evaluate lake sediment's susceptibility to piping. Field observations and discontinuity data analysis indicate that Rock City is a landslide that dammed the valley of Pond Drain, consequently forming the lake. The primary mode of slope movement involves lateral spreading that is associated with extension occurring along discontinuities. The Tuscarora Sandstone rock blocks comprising Rock

  11. Great Lakes: Great Gardening.

    ERIC Educational Resources Information Center

    New York Sea Grant Inst., Albany, NY.

    This folder contains 12 fact sheets designed to improve the quality of gardens near the Great Lakes. The titles are: (1) "Your Garden and the Great Lakes"; (2) "Organic Gardening"; (3) "Fruit and Vegetable Gardening"; (4) "Composting Yard Wastes"; (5) "Herbicides and Water Quality"; (6)…

  12. Utah: Salt Lake Region

    Atmospheric Science Data Center

    2014-05-15

    ... mountains including the Wasatch Range to the east, and the temperature difference between the Great Salt Lake and the overlying atmosphere ... snow cover between the winter and summer views, water color changes in parts of the Great Salt Lake are apparent in these images. The ...

  13. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

    Describes a study that included classroom lessons on hydroelectric power, the history and construction of a nearby lake, data recording, the use of field guides, and methods of counting natural populations. The study culminated in a field trip to the lake. (JRH)

  14. Great Lakes Teacher's Guide.

    ERIC Educational Resources Information Center

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  15. The Great Lakes.

    ERIC Educational Resources Information Center

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  16. The lakes of Titan.

    PubMed

    Stofan, E R; Elachi, C; Lunine, J I; Lorenz, R D; Stiles, B; Mitchell, K L; Ostro, S; Soderblom, L; Wood, C; Zebker, H; Wall, S; Janssen, M; Kirk, R; Lopes, R; Paganelli, F; Radebaugh, J; Wye, L; Anderson, Y; Allison, M; Boehmer, R; Callahan, P; Encrenaz, P; Flamini, E; Francescetti, G; Gim, Y; Hamilton, G; Hensley, S; Johnson, W T K; Kelleher, K; Muhleman, D; Paillou, P; Picardi, G; Posa, F; Roth, L; Seu, R; Shaffer, S; Vetrella, S; West, R

    2007-01-04

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

  17. The lakes of Titan

    USGS Publications Warehouse

    Stofan, E.R.; Elachi, C.; Lunine, J.I.; Lorenz, R.D.; Stiles, B.; Mitchell, K.L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.

    2007-01-01

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70?? north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table. ??2007 Nature Publishing Group.

  18. Great Lakes Teacher's Guide.

    ERIC Educational Resources Information Center

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  19. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

    Describes a study that included classroom lessons on hydroelectric power, the history and construction of a nearby lake, data recording, the use of field guides, and methods of counting natural populations. The study culminated in a field trip to the lake. (JRH)

  20. Lake Wobegon Dice

    ERIC Educational Resources Information Center

    Moraleda, Jorge; Stork, David G.

    2012-01-01

    We introduce Lake Wobegon dice, where each die is "better than the set average." Specifically, these dice have the paradoxical property that on every roll, each die is more likely to roll greater than the set average on the roll, than less than this set average. We also show how to construct minimal optimal Lake Wobegon sets for all "n" [greater…

  1. Lake Wobegon Dice

    ERIC Educational Resources Information Center

    Moraleda, Jorge; Stork, David G.

    2012-01-01

    We introduce Lake Wobegon dice, where each die is "better than the set average." Specifically, these dice have the paradoxical property that on every roll, each die is more likely to roll greater than the set average on the roll, than less than this set average. We also show how to construct minimal optimal Lake Wobegon sets for all "n" [greater…

  2. Great Salt Lake, Utah

    USGS Publications Warehouse

    Stephens, Doyle W.; Gardner, Joe F.

    1999-01-01

    This document is intended as a source of general information and facts about Great Salt Lake, Utah. This U.S. Geological Survey information sheet answers frequently asked questions about Great Salt Lake. Topics include: History, salinity, brine shrimp, brine flies, migratory birds, and recreation. Great Salt Lake, the shrunken remnant of prehistoric Lake Bonneville, has no outlet. Dissolved salts accumulate in the lake by evaporation. Salinity south of the causeway has ranged from 6 percent to 27 percent over a period of 22 years (2 to 7 times saltier than the ocean). The high salinity supports a mineral industry that extracts about 2 million tons of salt from the lake each year. The aquatic ecosystem consists of more than 30 species of organisms. Harvest of its best-known species, the brine shrimp, annually supplies millions of pounds of food for the aquaculture industry worldwide. The lake is used extensively by millions of migratory and nesting birds and is a place of solitude for people. All this occurs in a lake that is located at the bottom of a 35,000-square-mile drainage basin that has a human population of more than 1.5 million.

  3. Evaporation From Lake Superior

    NASA Astrophysics Data System (ADS)

    Spence, C.; Blanken, P.; Hedstrom, N.; Leshkevich, G.; Fortin, V.; Charpentier, D.; Haywood, H.

    2009-05-01

    Evaporation is a critical component of the water balance of each of the Laurentian Great Lakes, and understanding the magnitude and physical controls of evaporative water losses are important for several reasons. Recently, low water levels in Lakes Superior and Michigan/Huron have had socioeconomic, ecological, and even meteorological impacts (e.g. water quality and quantity, transportation, invasive species, recreation, etc.). The recent low water levels may be due to increased evaporation, but this is not known as operational evaporation estimates are currently calculated as the residual of water or heat budgets. Perhaps surprisingly, almost nothing is known about evaporation dynamics from Lake Superior and few direct measurements of evaporation have been made from any of the Laurentian Great Lakes. This research is the first to attempt to directly measure evaporation from Lake Superior by deploying eddy covariance instrumentation. Results of evaporation rates, their patterns and controlling mechanisms will be presented. The direct measurements of evaporation are used with concurrent satellite and climate model data to extrapolate evaporation measurements across the entire lake. This knowledge could improve predictions of how climate change may impact the lake's water budget and subsequently how the water in the lake is managed.

  4. The Great Lakes.

    ERIC Educational Resources Information Center

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  5. Structural Setting of the Emerson Pass Geothermal Anomaly, Pyramid Lake Paiute Reservation, Western Nevada

    NASA Astrophysics Data System (ADS)

    Anderson, R. B.; Faulds, J. E.

    2012-12-01

    The Pyramid Lake area is favorable for geothermal development due to the tectonic setting of the region. The Walker Lane belt, a dextral shear zone that accommodates ~20% relative motion between the Pacific and North American plates, terminates northwestward in northeast California. NW-directed dextral shear is transferred to WNW extension accommodated by N-to -NNE striking normal faults of the Basin and Range. As a consequence, enhanced dilation occurs on favorably oriented faults generating high geothermal potential in the northwestern Great Basin. The NW-striking right-lateral Pyramid Lake fault, a major structure of the northern Walker Lane, terminates at the southern end of Pyramid Lake and transfers strain to the NNE-striking down to the west Lake Range fault, resulting in high geothermal potential. Known geothermal systems in the area have not been developed due to cultural considerations of the Pyramid Lake Paiute Tribe. Therefore, exploration has been focused on discovering blind geothermal systems elsewhere on the reservation by identifying structurally favorable settings and indicators of past geothermal activity. One promising area is the northeast end of Pyramid Lake, where a broad left step between the west-dipping range-bounding faults of the Lake and Fox Ranges has led to the formation of a broad, faulted relay ramp. Furthermore, tufa mounds, mineralized veins, and altered Miocene rocks occur proximal to a thermal anomaly discovered by a 2-m shallow temperature survey at the north end of the step-over in Emerson Pass. Detailed geologic mapping has revealed a system of mainly NNE-striking down to the west normal faults. However, there are three notable exceptions to this generality, including 1) a prominent NW-striking apparent right-lateral fault, 2) a NW-striking down to the south fault which juxtaposes the base of the mid-Miocene Pyramid sequence against younger late Tertiary sedimentary rocks, and 3) a NNE-striking down to the east normal fault

  6. Structural Analysis of Active North Bozgush Fault Zone (NW Iran)

    NASA Astrophysics Data System (ADS)

    Saber, R.; Isik, V.; Caglayan, A.

    2013-12-01

    NW Iran is one of the seismically active regions between Zagros Thrust Belt at the south and Caucasus at the north. Not only large magnitude historical earthquakes (Ms>7), but also 1987 Bozgush, 1997 Ardebil (Mw 6.1) and 2012 Ahar-Varzagan (Mw 6.4) earthquakes reveal that the region is seismically active. The North Bozgush Fault Zone (NBFZ) in this region has tens of kilometers in length and hundreds of meters in width. The zone has produced some large and destructive earthquakes (1593 M:6.1 and 1883 M:6.2). The NBFZ affects the Cenozoic units and along this zone Eocene units thrusted over Miocene and/or Plio-Quaternary sedimentary units. Together with morphologic features (stream offsets and alluvial fan movements) affecting the young unites reveal that the zone is active. The zone is mainly characterized by strike-slip faults with reverse component and reverse faults. Reverse faults striking N55°-85°E and dip of 40°-50° to the SW while strike-slip faults show right lateral slip with N60°-85°W and N60°-80°E directions. Our structural data analysis in NBFZ indicates that the axis direction of σ2 principal stress is vertical and the stress ratio (R) is 0.12. These results suggest that the tectonic regime along the North Bozgush Fault Zone is transpressive. Obtained other principal stresses (σ1, σ3) results are compatible with stress directions and GPS velocity suggested for NW Iran.

  7. Buried Quaternary Valleys In NW Europe - Aquifers and Drilling Hazards

    NASA Astrophysics Data System (ADS)

    Huuse, M.; Lykke-Andersen, H.; Piotrowski, J.

    Buried Quaternary valleys are extremely widespread in the formerly glaciated, low- land areas of NW Europe (Huuse &Lykke-Andersen 2000, Fig. 4). The valleys may be several hundred metres deep, some kilometres across and few to several tens of kilometres long. Most of the deep valleys have irregular length profiles with sills and basins, unlike standard subaerial river systems. We interpret these as overdeepened valleys, formed mainly by subglacial meltwater erosion. Buried valleys located on- shore often provide sheltered reservoirs of clean groundwater, and much attention is presently focused on locating onshore valleys and quantifying their potential as groundwater aquifers. In nearshore areas, buried valleys may be a risk factor by pro- viding pathways of salt-water intrusion of onshore groundwater aquifers. Far offshore, buried valleys are located in the shallow subsurface above the prolific oil and gas fields of the central North Sea. Here, the valleys pose a risk for drilling operations by hosting shallow gas and potentially unstable sediments. The central North Sea is now largely covered by 3D seismic data, which often image the buried valleys in a level of de- tail much greater than that available onshore. Hence offshore valleys imaged by 3D seismic data may be used as analogues for groundwater reservoirs onshore NW Eu- rope. Here, we present examples of buried valleys from onshore, nearshore and far offshore locations, to illustrate how genetically and morphologically identical valleys may benefit or hamper the exploitation of subsurface accummulations of groundwater and hydrocarbons. Huuse, M. &Lykke-Andersen, H. 2000. Buried Quaternary valleys in the eastern Dan- ish North Sea: morphology and origin. Quaternary Science Reviews 19, 1233-1253.

  8. Assessing the potential environmental impact of Athabasca oil sands development in lakes across Northwest Saskatchewan

    NASA Astrophysics Data System (ADS)

    Ahad, J. M.; Cumming, B. F.; Das, B.; Sanei, H.

    2011-12-01

    The continued development of Canada's Athabasca oil sands poses a significant environmental challenge. Low buffered boreal lakes located downwind of the prevailing eastward wind direction may be threatened by acidification and elevated inputs of airborne contaminants such as polycyclic aromatic hydrocarbons (PAHs). An accurate assessment of the impact that increased levels of bitumen production may have on lakes in the region requires an understanding of the historic variability within these systems prior to at least the past several decades. Here we report concentrations of PAHs, δ13C and δ15N of organic matter (OM), Rock-Eval pyrolysis analyses, and distributions of n-alkanes in dated sediment cores from ten lakes located across NW Saskatchewan. Concentrations of PAHs were relatively low (< 100 ng/g for Σ 16 EPA Priority PAHs at each lake) and in general showed no substantial increases over the past 30 years. Retene, which is often associated with the combustion of coniferous wood, was generally the most abundant PAH amongst those reported, demonstrating the importance of forest fires as a principal PAH source. Plots of Hydrogen Index (HI) versus Oxygen Index (OI) fell within a relatively narrow range typical for sediments containing a high content of algal-derived OM. Relatively lower C/N ratios and higher abundances of C17 n-alkane in more recent sediments pointed to an increasingly larger component of algal-derived OM. In all ten lakes δ13C showed gradual upcore depletions that fell within the expected range for fossil fuel combustion (i.e., Suess effect), although this alone may not explain the up to ~3% depletion observed in several of the lakes. In conjunction with the other upcore trends these data may suggest a possible increase in primary productivity over the past several decades in many of the lakes studied. δ15N signatures were more variable, showing upcore increases in some lakes and upcore depletions in others. The increasingly lighter values

  9. Water quality of Lake Austin and Town Lake, Austin, Texas

    USGS Publications Warehouse

    Andrews, Freeman L.; Wells, Frank C.; Shelby, Wanda J.; McPherson, Emma

    1988-01-01

    Water-quality data collected from Lake Austin and Town Lake, following runoff, generally were not adequate to fully determine the effects of runoff on the lakes. Data collection should not to be limited to fixed-station sampling following runoff, and both lakes need to be sampled simultaneously as soon as possible following significant precipitation.

  10. Lake trout in northern Lake Huron spawn on submerged drumlins

    USGS Publications Warehouse

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  11. Lake Superior revisited 1984

    USGS Publications Warehouse

    MacCallum, Wayne R.; Selgeby, James H.

    1987-01-01

    The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably at or near pre-sea lamprey abundance. Stocks of lake whitefish (Coregonus clupeaformis) appear to have fully recovered; commercial catches are at or above historical levels. Lake herring (Coregonus artedii) are recovering rapidly in U.S. waters and are abundant in western Canadian waters. The population of rainbow smelt (Osmerus mordax), which declined in the 1970s, is recovering. Pacific salmon (Oncorhynchus) are becoming more abundant as a result of increased stocking in U.S. waters and are reproducing in most suitable tributaries; they have become significant in anglers' creels.

  12. Lake Morphometry for NHD Lakes in California Region 18 HUC

    EPA Pesticide Factsheets

    Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic systems. The lake morphometry dataset included here contains estimates of Surface Area, Shoreline Length, Shoreline Development, Maximum Depth, Mean Depth, Lake Volume, Maximum Lake Length, Mean Lake Width, Maximum Lake Width, and Fetch for each of the ??lakepond?? waterbodies in the NHDPlus V2. The current release of the datasets is version 0.1 and future refinements to the data are expected.

  13. Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

    EPA Pesticide Factsheets

    Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic systems. The lake morphometry dataset included here contains estimates of Surface Area, Shoreline Length, Shoreline Development, Maximum Depth, Mean Depth, Lake Volume, Maximum Lake Length, Mean Lake Width, Maximum Lake Width, and Fetch for each of the ??lakepond?? waterbodies in the NHDPlus V2. The current release of the datasets is version 0.1 and future refinements to the data are expected.

  14. Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

    EPA Pesticide Factsheets

    Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic systems. The lake morphometry dataset included here contains estimates of Surface Area, Shoreline Length, Shoreline Development, Maximum Depth, Mean Depth, Lake Volume, Maximum Lake Length, Mean Lake Width, Maximum Lake Width, and Fetch for each of the ??lakepond?? waterbodies in the NHDPlus V2. The current release of the datasets is version 0.1 and future refinements to the data are expected.

  15. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A.

    2003-01-01

    Six Fathom Bank-Yankee Reef, an offshore reef complex, was an historically important spawning area believed to represent some of the best habitat for the rehabilitation of lake trout Salvelinus namaycush in Lake Huron. Since 1986, lake trout have been stocked on these offshore reefs to reestablish self-sustaining populations. We sampled with beam trawls to determine the abundance of naturally reproduced age-0 lake trout on these offshore reefs during May-July in 1994-1998 and 2000-2002. In total, 123 naturally reproduced lake trout fry were caught at Six Fathom Bank, and 2 naturally reproduced lake trout fry were caught at nearby Yankee Reef. Our findings suggest that this region of Lake Huron contains suitable habitat for lake trout spawning and offers hope that lake trout rehabilitation can be achieved in the main basin of Lake Huron.

  16. Multiple oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)

    NASA Astrophysics Data System (ADS)

    Bos, Johanna A. A.; De Smedt, Philippe; Demiddele, Hendrik; Hoek, Wim Z.; Langohr, Roger; Marcelino, Vera; Van Asch, Nelleke; Van Damme, Dirk; Van der Meeren, Thijs; Verniers, Jacques; Boeckx, Pascal; Boudin, Mathieu; Court-Picon, Mona; Finke, Peter; Gelorini, Vanessa; Gobert, Stefan; Heiri, Oliver; Martens, Koen; Mostaert, Frank; Serbruyns, Lynn; Van Strydonck, Mark; Crombé, Philippe

    2017-04-01

    This paper presents the results of multi-disciplinary research carried out on the deposits of Moervaart depression, NW Belgium, one of the largest palaeolakes (∼25 km2) that existed during the Lateglacial interstadial in NW Europe. The multi-proxy study, including physical (organic matter and calcium carbonate, magnetic susceptibility, micromorphological), botanical (pollen, macrofossils, diatoms), zoological (ostracods, molluscs, chironomids) and chemical analyses (stable carbon and oxygen isotopes) has resulted in a detailed reconstruction of the Lateglacial landscape as well of the local conditions that prevailed in the lake itself. A chronology of the record was provided by radiocarbon dating and comparison with radiocarbon dates of the nearby Rieme site. These yielded a good match with the regional biostratigraphy. During the Lateglacial, vegetation and geomorphology of the landscape in general changed from a tundra landscape to a boreal forest. The vegetation development, however, was interrupted by a number of cold reversals. Three centennial-scale cold oscillations are present in the record: 1) the so-called Older Dryas corresponding to GI-1d in the Greenland ice-cores, 2) a short and pronounced cold event during the early Allerød, which could be correlated to GI-1c2 and 3) a cooling event during the late Allerød probably corresponding to the Intra Allerød Cold Period (IACP) or GI-1b. The latter most likely was responsible for the disappearance of the Moervaart palaeolake.

  17. High-resolution palaeoecological and sedimentological records as a tool for understanding pre- and protohistoric settlement and land-use systems in Sandy Flanders (NW Belgium)

    NASA Astrophysics Data System (ADS)

    Court-Picon, Mona; Polfliet, Tim; Serbruyns, Lynn; de Smedt, Phillippe; Zwertvaegher, Ann; Bats, Machteld; de Reu, Jeroen; Werbrouck, Ilke; Verniers, Jacques; Crombe, Philippe

    2010-05-01

    The area of Sandy Flanders, situated between the North Sea coast and the lower course of the Scheldt River in NW Belgium, is a relatively flat and low-lying area situated at the southern limit of the lowland cover sand region of the NW European plain. During the Late Pleniglacial and the Late Glacial, numerous, generally small but elongated sand dunes, shallow lakes and wet depressions were formed. During the last three decades intense archaeological prospection has taken place in this region, which is now one of the most intensively surveyed areas of NW Europe. This has led to the production of archaeological distribution maps, which show a distinct pattern regarding the temporal and spatial distribution of these archaeological sites. Some areas with a presumed high ecological value, such as the large but shallow Late Glacial fossil lake of the Moevaart Depressie (ca. 15km long and 2,5km wide), seem to have been attractive settlement locations in Prehistory, given the high amount of close-lying sites along its borders and on the cover sand ridge on its northern border. Habitation however seems to have ‘moved' in time, and is completely absent in Protohistory and even the Roman Period. During the Late Glacial and Holocene the landscape in the Belgian area of Sandy Flanders was subjected to major changes due to climatic fluctuations, and besides human factors, environmental conditions such as topography, soil, vegetation, but also hydrology and climate, may have influenced settlement conditions throughout time and played a role in this change in site location and the occupational history of the region. In this light an inter-disciplinary project 'Prehistoric settlement and land-use systems in Sandy Flanders (NW Belgium): a diachronic and geoarchaeological approach' (GOA project, UGent), involving archaeology, geography, palaeoecology, sedimentology and geophysical survey, has been undertaken. The study of both "empty" and densely inhabited areas is ongoing and

  18. Lake whitefish and lake herring population structure and niche in ten south-central Ontario lakes

    USGS Publications Warehouse

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

    This study compares simple fish communities of ten oligotrophic lakes in south-central Ontario. Species densities and population size structure vary significantly among these lake communities depending on fish species present beyond the littoral zone. Lake whitefish are fewer and larger in the presence of lake herring than in their absence. Diet analysis indicates that lake whitefish shift from feeding on both plankton and benthic prey when lake herring are absent to a primarily benthic feeding niche in the presence of lake herring. When benthic round whitefish are present, lake whitefish size and density decline and they move lower in the lake compared to round whitefish. Burbot are also fewer and larger in lakes with lake herring than in lakes without herring. Burbot, in turn, appear to influence the population structure of benthic coregonine species. Lower densities of benthic lake whitefish and round whitefish are found in lakes containing large benthic burbot than in lakes with either small burbot or where burbot are absent. Predation on the pelagic larvae of burbot and lake whitefish by planktivorous lake herring alters the size and age structure of these populations. As life history theory predicts, those species with poor larval survival appear to adopt a bet-hedging life history strategy of long-lived individuals as a reproductive reserve.

  19. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    USGS Publications Warehouse

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  20. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    USGS Publications Warehouse

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  1. Whiting in Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Satellites provide a view from space of changes on the Earth's surface. This series of images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard the Orbview-2 satellite shows the dramatic change in the color of Lake Michigan during the summer. The bright color that appears in late summer is probably caused by calcium carbonate-chalk-in the water. Lake Michigan always has a lot of calcium carbonate in it because the floor of the lake is limestone. During most of the year the calcium carbonate remains dissolved in the cold water, but at the end of summer the lake warms up, lowering the solubility of calcium carbonate. As a result, the calcium carbonate precipitates out of the water, forming clouds of very small solid particles that appear as bright swirls from above. The phenomenon is appropriately called a whiting event. A similar event occured in 1999, but appears to have started later and subsided earlier. It is also possible that a bloom of the algae Microcystis is responsible for the color change, but unlikely because of Lake Michigan's depth and size. Microcystis blooms have occured in other lakes in the region, however. On the shore of the lake it is possible to see the cities of Chicago, Illinois, and Milwaukee, Wisconsin. Both appear as clusters of gray-brown pixels. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  2. Yellowstone lake nanoarchaeota.

    PubMed

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P; Nealson, Kenneth; McDermott, Timothy R

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  3. Yellowstone Lake Nanoarchaeota

    PubMed Central

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E.; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P.; Nealson, Kenneth; McDermott, Timothy R.

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations. PMID:24062731

  4. Ecology under lake ice.

    PubMed

    Hampton, Stephanie E; Galloway, Aaron W E; Powers, Stephen M; Ozersky, Ted; Woo, Kara H; Batt, Ryan D; Labou, Stephanie G; O'Reilly, Catherine M; Sharma, Sapna; Lottig, Noah R; Stanley, Emily H; North, Rebecca L; Stockwell, Jason D; Adrian, Rita; Weyhenmeyer, Gesa A; Arvola, Lauri; Baulch, Helen M; Bertani, Isabella; Bowman, Larry L; Carey, Cayelan C; Catalan, Jordi; Colom-Montero, William; Domine, Leah M; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N; Jolley, Jeff C; Kahilainen, Kimmo K; Kaup, Enn; Kehoe, Michael J; MacIntyre, Sally; Mackay, Anson W; Mariash, Heather L; McKay, Robert M; Nixdorf, Brigitte; Nõges, Peeter; Nõges, Tiina; Palmer, Michelle; Pierson, Don C; Post, David M; Pruett, Matthew J; Rautio, Milla; Read, Jordan S; Roberts, Sarah L; Rücker, Jacqueline; Sadro, Steven; Silow, Eugene A; Smith, Derek E; Sterner, Robert W; Swann, George E A; Timofeyev, Maxim A; Toro, Manuel; Twiss, Michael R; Vogt, Richard J; Watson, Susan B; Whiteford, Erika J; Xenopoulos, Marguerite A

    2017-01-01

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer 'growing seasons'. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass.

  5. Whiting in Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Satellites provide a view from space of changes on the Earth's surface. This series of images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard the Orbview-2 satellite shows the dramatic change in the color of Lake Michigan during the summer. The bright color that appears in late summer is probably caused by calcium carbonate-chalk-in the water. Lake Michigan always has a lot of calcium carbonate in it because the floor of the lake is limestone. During most of the year the calcium carbonate remains dissolved in the cold water, but at the end of summer the lake warms up, lowering the solubility of calcium carbonate. As a result, the calcium carbonate precipitates out of the water, forming clouds of very small solid particles that appear as bright swirls from above. The phenomenon is appropriately called a whiting event. A similar event occured in 1999, but appears to have started later and subsided earlier. It is also possible that a bloom of the algae Microcystis is responsible for the color change, but unlikely because of Lake Michigan's depth and size. Microcystis blooms have occured in other lakes in the region, however. On the shore of the lake it is possible to see the cities of Chicago, Illinois, and Milwaukee, Wisconsin. Both appear as clusters of gray-brown pixels. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  6. 3. Mass Movements, Erosion Patterns and Sediment Transport along the Sutlej River (NW-Himalaya)

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Thiede, R. C.; Strecker, M. R.

    2003-04-01

    The spatial and temporal distribution of mass movements in active orogens can provide valuable insights into the relation between sedimentation and erosion processes. In areas of high relief, hillslope processes dominate surface geomorphology and can lead to the damming of rivers and formation of lakes upstream. These basins provide a record of natural climatic variations along the river profile and divide the regions in different sedimentational and erosional compartments. To characterize the variations, digital elevation models were used for quantitative analysis of topography, basin-fill volume, and active channel gradients. High-resolution spatial data (digitized 1:25,000 to 1:100,000 topographic maps) and ASTER-derived digital elevation models (DEM) were processed to analyze topography. Combined with geological field measurements and observations we could distinguish erosional patterns within several study areas in the NW Himalayas. Precipitation data were derived from calibrated passive microwave satellite data (SSMI), providing information on a 10 year time series at sufficient spatial resolution (12.5 km2). Modern sediment flux and transport, discharge, geomorphic field observations including river width and slope define the boundary conditions for surface erosion calculations. The Sutlej Valley (32N, 78E) in NW India is dominated by the antecedent Sutlej River, the third-largest river in the Himalayas. It flows perpendicular through the orogen and cuts through all major geologic units of the Tethyan Himalaya, High and Lesser Himalayan Crystallines, and Lower Himalayan units. The geomorphologic changes across thrust faults bounding these units provide valuable insights into the evolution of the orogen. Tectonically active sectors of the orogen are manifested by pronounced knickpoints in longitudinal river profiles that cross active thrust faults. In contrast to other parts of the Himalayas, no (re-) activation of the MCT and STDS can be seen in the

  7. Ecology of playa lakes

    USGS Publications Warehouse

    Haukos, David A.; Smith, Loren M.

    1992-01-01

    Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

  8. Landscape History of Grosses Moos, NW Swiss Alpine Foreland.

    NASA Astrophysics Data System (ADS)

    Joanna Heer, Aleksandra; Adamiec, Grzegorz; Veit, Heinz; May, Jan-Hendrik; Novenko, Elena; Hajdas, Irka

    2017-04-01

    The western Swiss Plateau with Lake Neuchâtel is part of the alpine foreland and among the key areas for the reconstruction of environmental changes since the last postglacial. This study was carried out in a landscape located NE of the lake and called Grosses Moos (The Large Fen) - currently designated the Swiss largest, continuous farming area, after the fen was drained in course of landscape engineering projects performed in Switzerland at the end of the 19th century. The study contributes new results from nine excavations of littoral ridges identified in Grosses Moos, and integrates sedimentology, paleo-environmental analysis and three independent chronological methods. Radiocarbon dating, pollen analysis and optically stimulated luminescence (OSL) were applied to the sediments. While pollen and radiocarbon follow the standard procedures, the evaluation of the luminescence age estimates demanded adjustment according to the physical and microdosimetric properties of the alpine quartz, and consideration of the peculiarities of the changing littoral environments of Grosses Moos. The Grosses Moos landscape developed on the temporary surface of the post-Last Glacial sedimentary infill of the over-deepened glacial Aare valley. In this study the landscape history has been fitted into the existing supraregional time scales of NGRIP, the Swiss bio-zones system and the human history based on archaeological and historic records and covers a time span of up to 15'000 yr b2k. The wide-ranging suite of geomorphic features and sedimentary sequences, including littoral lake sediments, beach ridges, dunes, palaeo-channels, peat and colluvial deposits, enable the extensive reconstruction of spatially and temporally variable natural shaping processes. In addition, our results indicate remobilization of soil, colluvium, and sediment due to human settlement activities since the Neolithic - with an important increase in sediment load and spatial variability since the Bronze Age

  9. Lake Tengiz from space

    NASA Image and Video Library

    2017-09-28

    In orbit above the semi-desert grasslands in Kazakhstan, an astronaut aboard the International Space Station spotted one of the few features that stand out. Lake Tengiz is the only large lake (1590 square kilometers, 615 square miles) in northern Kazakhstan. Through white wisps of cloud, the crew member photographed the 50 kilometer-long eastern shore of the lake, with its thin, winding islands and white beaches. The islands and intervening waterways make a rich habitat for birds in this part of Asia. At least 318 species of birds have been identified at the lake; 22 of them are endangered. It is the northernmost habitat of the pink flamingo. The lake system is Kazakhstan’s first UNESCO World Heritage Site, and it has been declared a RAMSAR wetland site of international importance. Part of the richness of area is its complex hydrology. Fresh water enters the system via the Kulanutpes River, so there are small lakes (lower right) full of fresh water. But in this closed basin, the water in the main lake (top) slowly evaporates, becoming salty. Winds stir up bigger waves on the main lake, dispersing sediment and salt and making the water a cloudier and lighter blue-green. (Another astronaut photograph shows the entire lake system, while this story provides more information.) The strange shape of the islands is not easy to interpret. They may be drowned remnants of delta distributaries of the Kulanutpes River. Westerly winds probably have had a smoothing effect on the shorelines, especially in a shallow lake like Tengiz, which is only about 6 meters (20 feet) deep. The lake has an exciting history for people who follow space exploration. In 1976, a Soyuz spacecraft landed in the lake near the north shore (top right). The capsule crashed through the ice and sank during an October snowstorm when temperatures were -22°C (-8°F). Because of low power, the capsule was unheated and the crew was feared lost. It was many hours before the airtight capsule was located and

  10. Lake Mead, NV

    NASA Image and Video Library

    1973-06-22

    SL2-03-192 (22 June 1973) --- Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red. Photo credit: NASA

  11. Lake Mead, NV

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red.

  12. Yamzho Yumco Lake, Tibet

    NASA Image and Video Library

    2017-02-01

    Yamzho Yumco (Sacred Swan) Lake in Tibet is surrounded by snow-capped mountains and is one of the three largest sacred lakes. It is highly crenellated with many bays and inlets. The lake is home to Samding Monastery, headed by a female re-incarnation (Wikipedia). The image was acquired March 6, 2014, covers an area of 49.8 by 60 km, and is centered at 28.9 degrees north, 90.6 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA21304

  13. Lake Poopo, Bolivia

    NASA Image and Video Library

    2017-04-28

    In the high plains of the Andes in Bolivia, Lake Poopo has virtually vanished, as shown in this image from NASA Terra spacecraft. Once covering over 3,000 square kilometers, the lake essentially dried up in 2015. What led to Lake Poopo's demise? Water diversions upstream, weather extremes and recurrent droughts are thought to blame. The images cover an area of 48.9 by 55.1 km, were acquired February 14, 2001 and November 6, 2016, and are located near 18.7 degrees south, 67.1 degrees west. https://photojournal.jpl.nasa.gov/catalog/PIA21546

  14. National Lakes Assessment Data

    EPA Pesticide Factsheets

    The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S. Environmental Protection Agency (EPA) worked with states and tribes to conduct the assessment in 2007. Data for each parameter sampled in the National Lakes Assessment (NLA) are available for downloading in a series of files as comma separated values (*.csv). Each *.csv data file has a companion text file (*.txt) that lists a dataset label and individual descriptions for each variable. Users should view the *.txt files first to help guide their understanding and use of the data.

  15. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    EPA Pesticide Factsheets

    Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic systems. The lake morphometry dataset included here contains estimates of Surface Area, Shoreline Length, Shoreline Development, Maximum Depth, Mean Depth, Lake Volume, Maximum Lake Length, Mean Lake Width, Maximum Lake Width, and Fetch for each of the ??lakepond?? waterbodies in the NHDPlus V2. The current release of the datasets is version 0.1 and future refinements to the data are expected.

  16. A Holocene speleothem record from Morocco, NW Africa

    NASA Astrophysics Data System (ADS)

    Wassenburg, Jasper; Fietzke, Jan; Richter, Detlev; Immenhauser, Adrian

    2010-05-01

    A well dated Holocene speleothem (stalagmite) from the Middle Atlas Mountains in Morocco has been investigated for its continental climate record. The aim is to compile an improved understanding of the climatically complex triple point of the North Atlantic, Mediterranean and Saharan / Monsoonal climate realms in NW Africa. At present, only few studies concerning continental climate reconstructions from NW Africa have been published (Lamb et al. 1995, Cheddadi et al. 1998, Genty et al. 2006). Given the significance of this region, this lack of data forms a strong motivation for additional, well dated climate records. The speleothem (GP2) was sampled in the 'Grotte de Piste' (ca 800 m above sea level), mean annual precipitation is about 930 mm (mainly falling in the winter season) and the mean annual temperature is about 13° C. GP2 is 60 cm tall and grew - based on U/Th MC-ICP-MS data - continuously between 11.5 kyr BP (early Holocene) and 2.9 kyr BP (late Holocene). X-Ray Diffraction data indicate a mainly aragonitic mineralogy. 'Hendy tests' suggest that CaCO3 precipitation was close to isotopic equilibrium with respect to oxygen isotopes, however kinetic effects might have influenced carbon isotopes. Carbon and oxygen isotope data have been measured along a transect with increments of approximately 1 mm representing a resolution of about 15 yrs. Highly covariant oscillations in δ13C and δ18O with an average cyclicity of about 410 yrs. are observed. These oscillations coincide with macroscopically visible high density and low density layers, possibly reflecting a higher or lower amount of inclusions and perhaps higher and lower growth rates. Geochemical analysis of speloan aragonite is accompanied by cave monitoring that has started in November 2009. Parameters quantified include: drip water parameters, cave air humidity, pCO2 and cave air temperature. Precipitation experiments using watch glasses will also be performed. References Cheddadi, R., Lamb, H. F

  17. Can lake sensitivity to desiccation be predicted from lake geometry?

    NASA Astrophysics Data System (ADS)

    Torabi Haghighi, Ali; Menberu, Meseret Walle; Aminnezhad, Mousa; Marttila, Hannu; Kløve, Bjørn

    2016-08-01

    Declining lake levels (Aral Sea syndrome) can be caused by changes in climate, increased water use or changed regulation patterns. This paper introduces a novel lake geometry index (LGI) to quantify lake hydrological characteristics. The index was developed using a large representative dataset of lake hypsographic characteristics from 152 lakes and man-made reservoirs. Using the LGI index, lakes can be classified into five groups: groups 1-4 when LGI is 0.5-2.5, 2.5-4.5, 4.5-6.5 and 6.5-8.5, respectively, and group 5 when LGI is >8.5. Naturally shallow and vast lakes and wetlands fall into the first group and deep man-made reservoirs in narrow valleys are in group 5. The response of three different lake systems (LGI 0.75, 2.75 and 6.5) to different water flow scenarios was then simulated using the water balance equation. From this, the index 'potential lake area' (Apot) was developed to show lake responses to changed hydro-climatological conditions. Apot and LGI can be used to classify lakes into open or closed systems. Simulations showed that lakes with low LGI have a shorter response time to flow and climate changes. As a result, the impact of water balance restoration is faster for lakes with low LGI than for lakes with high LGI. The latter are also more vulnerable to climate variation and change.

  18. 14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED CONCRETE FORMS, August 1976 - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

  19. 52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR THE AMMONIA DISTILLATE IN FOREGROUND. MAY 21, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  20. Lake Ilopango, El Salvador

    NASA Image and Video Library

    2015-03-10

    Lake Ilopango is a crater lake which fills a volcanic caldera in central El Salvador, immediately east of the capital city San Salvador. The caldera collapsed most recently in about 500 AD, producing 20 times as much ash as the Mount St. Helens eruption, and blanketing an area of at least 10,000 square kilometers waist-deep in ash. The only historical eruption occurred in 1879, forming lava domes, now islets in the lake. Quetzaltepec is the stratovolcano just west of the city. Its last eruption in 1917 produced lavas flowing down the northwest flank, and evaporated the crater lake. The image was acquired March 5, 2006, covers an area of 27 by 42 km, and is located at 13.7 degrees north, 89.1 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19237

  1. Challenges to the Lake

    EPA Science Inventory

    During the past decade we have extensively studied coastal ecosystems in the Great Lakes. Some research efforts have linked coastal receiving systems to conditions in their contributing watersheds; others have focused on developing invasive species detection and monitoring strat...

  2. About Deer Lake AOC

    EPA Pesticide Factsheets

    Named an Area of Concern under the Great Lakes Water Quality Agreement of 1987, due to beneficial use impairments caused by mercury contamination: consumption restrictions, deformities or reproductive problems, eutrophication.

  3. Pompton Lakes Photo Gallery

    EPA Pesticide Factsheets

    This gallery provides representative photographs of the soil removal and dredging operations within the Pompton Lake Study Area (PLSA) performed starting in 2016 through the present. It will be periodically updated in conjunction with the progress of the

  4. Lake Sharpe, South Dakota

    NASA Image and Video Library

    2014-03-26

    NASA Terra spacecraft views central South Dakota, where the Missouri River forms a meander bend, creating Lake Sharpe. Eventually, the Missouri River will cut through the skinny peninsula, creating a shorter path.

  5. Challenges to the Lake

    EPA Science Inventory

    During the past decade we have extensively studied coastal ecosystems in the Great Lakes. Some research efforts have linked coastal receiving systems to conditions in their contributing watersheds; others have focused on developing invasive species detection and monitoring strat...

  6. Is Lake Tahoe Terminal?

    NASA Astrophysics Data System (ADS)

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.

    2014-12-01

    Lake Tahoe, an iconic ultra-oligotrophic lake in the central Sierra Nevada, has been studied intensively since 1968, with the goal of understanding and ultimately controlling its eutrophication and loss of clarity. Research on the lake has included a) periodic profiles of primary productivity, nutrients, temperature, and plankton; b) Secchi depth; c) nutrient limitation experiments; d) analysis of sediment cores; e) radiocarbon dating of underwater in-place tree stumps; g) analysis of long-term temperature trends. Work in its watershed has included a) monitoring of stream discharge, sediment and nutrients at up to 20 stream gaging stations; b) monitoring of urban runoff water quality at selected sites; c) development of a GIS data base, including soils, vegetation, and land use. Based on these studies, we know that a) primary productivity in the lake is limited by phosphorus, and continues to increase; b) the loss of clarity continues, but at a declining rate; c) the lake has been warming since 1970, and its resistance to deep mixing is increasing; d) historically the lake level drops below the outlet elevation about one year in seven; e) 6300 to 4300 yrs BP lake level was below the present outlet elevation long enough for large trees to grow; f) the date of the peak snowmelt runoff is shifting toward earlier dates; g) after accounting for annual runoff, loads of nutrients and suspended sediment have declined significantly in some basin streams since 1980. Downscaled outputs from GCM climatic models have recently been used to drive hydrologic models and a lake clarity model, projecting future trends in the lake and watersheds. Results show a) the temperature and thermal stability will likely continue to increase, with deep mixing shutting down in the latter half of this century; b) the lake may drop below the outlet for an extended period beginning about 2085; c) the annual snowpack will continue to decline, with earlier snowmelt and shift from snowfall to rain; d

  7. Antarctic subglacial lake discharges

    NASA Astrophysics Data System (ADS)

    Pattyn, Frank

    Antarctic subglacial lakes were long time supposed to be relatively closed and stable environments with long residence times and slow circulations. This view has recently been challenged with evidence of active subglacial lake discharge underneath the Antarctic ice sheet. Satellite altimetry observations witnessed rapid changes in surface elevation across subglacial lakes over periods ranging from several months to more than a year, which were interpreted as subglacial lake discharge and subsequent lake filling, and which seem to be a common and widespread feature. Such discharges are comparable to jökulhlaups and can be modeled that way using the Nye-Röthlisberger theory. Considering the ice at the base of the ice sheet at pressure melting point, subglacial conduits are sustainable over periods of more than a year and over distances of several hundreds of kilometers. Coupling of an ice sheet model to a subglacial lake system demonstrated that small changes in surface slope are sufficient to start and sustain episodic subglacial drainage events on decadal time scales. Therefore, lake discharge may well be a common feature of the subglacial hydrological system, influencing the behavior of large ice sheets, especially when subglacial lakes are perched at or near the onset of large outlet glaciers and ice streams. While most of the observed discharge events are relatively small (101-102 m3 s-1), evidence for larger subglacial discharges is found in ice free areas bordering Antarctica, and witnessing subglacial floods of more than 106 m3 s-1 that occurred during the middle Miocene.

  8. Lake Superior, Duluth, MN

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

  9. Dragon Lake, Siberia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nicknamed 'Dragon Lake,' this body of water is formed by the Bratskove Reservoir, built along the Angara river in southern Siberia, near the city of Bratsk. This image was acquired in winter, when the lake is frozen. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on December 19, 1999. This is a natural color composite image made using blue, green, and red wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  10. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The fluctuating water levels of Lake Chad, (13.0N, 15.0E) at the intersection of the borders of Chad, Niger and Cameroon in the Sahara Desert, is an index of the drought in Africa. The lake level continues to decrease as indicated by the growing number and extent of emerging islands as previously submerged ancient sand dunes become visible. The water impounded between the dunes is probably because of local rainfall rather than a reversal of desertification.

  11. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The fluctuating water levels of Lake Chad, (13.0N, 15.0E) at the intersection of the borders of Chad, Niger and Cameroon in the Sahara Desert, is an index of the drought in Africa. The lake level continues to decrease as indicated by the growing number and extent of emerging islands as previously submerged ancient sand dunes become visible. The water impounded between the dunes is probably because of local rainfall rather than a reversal of desertification.

  12. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Once a great inland lake, Lake Chad (13.0N, 14.0E) in the Sahara Desert at the intersection of the African nations of Chad, Niger, Nigeria and Cameroon, is now in decline. The larger northern lobe is almost totally dry and slowly filling in with encroaching sand dunes. The southern lobe, still retains some water in the lower center but the water surface area is less than 2000 square kilometers and sand dunes are filling in the north end.

  13. Dragon Lake, Siberia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nicknamed 'Dragon Lake,' this body of water is formed by the Bratskove Reservoir, built along the Angara river in southern Siberia, near the city of Bratsk. This image was acquired in winter, when the lake is frozen. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on December 19, 1999. This is a natural color composite image made using blue, green, and red wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  14. Reprocessing and Interpretation of the High Resolution Seismic Data from Northern Marmara Continental Shelf, NW Turkey

    NASA Astrophysics Data System (ADS)

    Nasif, Aslıhan; Dondurur, Derman; Ergintav, Semih; Cifci, Gunay

    2015-04-01

    The Marmara Sea is an inland sea located in the NW of Turkey with a maximum depth of 1270 m, and consists of a 3 major sub-basins. The active dextral North Anatolian Fault (NAF) passes through the basins, which shapes the general morphology and forms the tectonic settlement of the Marmara Sea. The investigations for the Marmara Sea are now important since İstanbul city, which is the most populous and economically the most important city of Turkey, is located just north of the Marmara Sea, quite close to the NAF. In order to define the morphology and structural state of the northern continental shelf of the Marmara Sea, we collected 224 km of multichannel high resolution seismic and 338 km of Chirp subbottom profiler data along the shallow shelf in 2007. A 600 m long, 96 channel digital seismic streamer, and a Generator-Injector (GI) gun was used to obtain high resolution seismic data. The Chirp data was collected a 2.75-6.75 kHz over-the-side-mount transducer system. The data have been processed using a conventional data processing flow. The scope of the present study is to re-process and to interpret the seismic and Chirp data between Silivri and Sarayburnu on the northern Marmara shelf up to 100 m water depth. The active tectonic characteristics of the area, especially its geological connection with the terrestrial area, are investigated using acoustic data. In addition, offshore continuity of the of the Çatalca Fault zone is investigated. The Çatalca Fault enters the shelf along the B. Çekmece Lake and can be tracked in the SSE direction on the seismic data. The seismic data is tied to North Marmara-1 well located on the central part of the shelf area, and distributions and thicknesses of the pre-Miocene sediments are mapped using a jump-correlation to the well information. The seismic data located at the southernmost part of the shelf along the shelf break also indicate the presence of active sediment erosion. Behind the shelf break, the slope inclination

  15. Ba-rich sanidine megacrysts in trachytic rocks of Eslamy volcano, NW Iran

    NASA Astrophysics Data System (ADS)

    Aßbichler, Donjá; Asadpour, Manijeh; Heuss-Aßbichler, Soraya; Kunzmann, Thomas

    2016-04-01

    The Eslamy volcano is located on a peninsula at the eastern coast of Urumieh lake, NW Iran. The complex stratovolcano with gentle slope flanks exposes a collapsed caldera in the central part. Specific features are different sanidine rich rocks that occur in form of ejecta and flows. According to the field observations they are products of one volcanic event. XRF measurements show they all have trachytic compositions. Typical for this locality are the large sanidine phenocrysts. In the trachytic flow the sanidine crystals reach average size of ~4 cm embedded in a greenish-blue matrix consisting mainly of crystallized feldspar and subordinate pyroxen. Occasionally feldspar megacrysts of approx. 10 cm were observed. Na content of the sanidine megacrysts varies between 0.05 - 0.5 pfu with higher concentrations in the cores. Furthermore they show oscillatory zoning patterns caused by variations of Ba content (0-0.04 pfu). The matrix of the trachytic flow consist mainly of interlocking sanidine crystals (0.05-0.45 pfu Na) partly with Ba-rich cores containing up to 0.06 pfu Ba. In contrast to the megacrysts they show slightly higher Fe contents (0.025-0.035 pfu). The volcanic ejecta with bombs of approx. 50 cm in size were found in one distinct layer within a pyroclastic horizon. The average diameter of the feldspar phenocrysts is much smaller (0.5-2 cm). Sanidine is the main phase of these rocks (up to 80 %). As mafic phase up to 30 % pyroxen (mainly diospide) ± biotite can be observed. Accessories are magnetite ± apatite ± titanite ± zircon. In contrast to the flow rocks the main phase of the matrix of the ejecta is always glass with higher Fe2O3 (total) contents (up to 6 wt.-%) indicating a fast cooling of the sample due to ejection. They are completely depleted in Ba. In two samples zoned feldspar relicts enclosed in glass show remolten rims. Similar to flow rocks the feldspar phenocrysts of all ejecta show a complex zoning pattern, e.g. three samples expose high

  16. Semiquantitative multi-hazard risk assessment concepts for a himalayan watershed in NW-Bhutan

    NASA Astrophysics Data System (ADS)

    Brauner, M.; Leber, D.; Haeusler, H.; Agner, P.; Payer, T.; Tobgay, T.; Wangda, D.

    2003-04-01

    In the Pho Chhu watershed in NW-Bhutan, settlement activity concentrates on broad and pro-duc-tive valley areas, 50 to 80 kilometres downstream of glacial flood sources. Despite an time lag of 5 to 7 hours between initiation and arrival of the breach flood, the low reliability of telecommunication line results in a short pre-warning time. Upstreams, at the main Himalayan ridge, several glaciers coalescence at the valley end, forming a glacial environment with highly inter-linked, possibly hazardous glacial and gravitational processes, which also endanger small isolated settlements nearby the glaciers. Here glacial lake outbursts may be triggered by glacier surges out of water pockets, surge waves due to ice or rock fall and inherent in-stability of the moraines themselves. During flood propagation lateral gravitational processes in loose sediments and tills may result in temporal blockage. Therefore a three stage risk management concept is proposed, dividing into: (1) Local, quickly to establish countermeasures, such as technical measures with low maintenance expenditure and low failure risk, manual monitoring and improved manual telecommunication line. (2) Regional hazard zone delineation to enable hazard awareness and preparedness, and limited relocation activity. (3) And finally regional implementation of an technical early warning system. Hazard risk assessment is carried out by means of qualitative mapping of gravitative processes and quantitative process simulation of dam stability, dam breaching and flood propagation. As time series for identification of accurate time-magnitude relations are not available or questionable due to the changing environmental con-ditions, scenario modelling of the governing processes is utilised to account for process magnitude relation and process inter-linkage. Based on these procedures a semi-quantitative hazard zonation concept, taking into account quantitative process influence zones and qualitative frequency estimation has

  17. Soil organic matter contribution to the NW Mediterranean (Invited)

    NASA Astrophysics Data System (ADS)

    Kim, J.; Buscail, R.; Blokker, J.; Kerhervé, P.; Schouten, S.; Ludwig, W.; Sinninghe Damsté, J. S.

    2009-12-01

    The BIT (Branched and Isoprenoid Tetraether) index has recently been introduced as a proxy for soil organic matter input and is based on the relative abundance of non-isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs) derived from organisms living in terrestrial environments versus a structurally related isoprenoid GDGT “crenarchaeol” produced by marine Crenarchaeota (Hopmans et al., 2004). In this study, detailed spatial distribution patterns of BIT index were investigated in combination with other organic parameters in the continental margin of the north western Mediterranean. Based on a transect sampling strategy from source (land) to sink (sea) via river, we analysed a variety of soils from the Têt and Rhône basins, suspended particulate matter in waters of the Têt and Rhône rivers flowing into the Gulf of Lions, and marine surface sediments from the Gulf of Lions collected before and after a flood occurred in June 2008. Our study allows us to track BIT values along the transport pathway of soil organic matter and thus to estimate soil organic matter contribution in marine sediments in the Gulf of Lions (NW Mediterranean), a river-dominated continental margin. Hopmans, E.C., Weijers, J.W.H., Schefuss, E., Herfort, L., Sinninghe Damsté, J.S., Schouten, S., 2004. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoidtetraether lipids. Earth and Planetary Science Letters 224, 107-116.

  18. Past Glaciation in the Sierra Aconquija, NW Argentina

    NASA Astrophysics Data System (ADS)

    D'Arcy, M. K.; Mey, J.; Schildgen, T. F.

    2016-12-01

    Multiple Pleistocene glaciations have occurred in the subtropical Andes, leaving behind extensive moraines in areas that are now arid and completely unglaciated. These are important terrestrial palaeoclimate records, yet we have a poor understanding of their timings and the regional changes in temperature and moisture transport that caused them. Here, we present an analysis of past glaciation in the Sierra Aconquija ( 27° S), NW Argentina. This mountain range has peak elevations above 5000 m and lies in a climatically sensitive location, receiving heavy precipitation on its eastern side from the South American Monsoon (>1500 mm/yr), while also creating a powerful rain shadow on its western side ( 250 mm/yr). The range has no glaciers today, but exhibits clear evidence for past glacial activity. We develop a new method for discriminating between different generations of moraines at a high spatial resolution, using new Sentinel-2 multispectral satellite imagery. We characterise three distinct glacial advances in the Sierra Aconquija, which each terminate at significantly different elevations between 3500 and 4400 m. We map their spatial extents in detail in order to explore the sensitivity of past glaciation to the strong orographic gradient in climate at this location. Finally, we model the deviations in temperature and precipitation that are needed to explain these past glacial episodes in this part of the Andes, and explore the implications for climatic reorganisation in the region.

  19. Assessment of Quercus flowering trends in NW Spain.

    PubMed

    Jato, V; Rodríguez-Rajo, F J; Fernandez-González, M; Aira, M J

    2015-05-01

    This paper sought to chart airborne Quercus pollen counts over the last 20 years in the region of Galicia (NW Spain) with a view to detecting the possible influence of climate change on the Quercus airborne pollen season (APS). Pollen data from Ourense, Santiago de Compostela, Vigo and Lugo were used. The Quercus airborne pollen season was characterized in terms of the following parameters: pollen season start and end dates, peak pollen count, pollen season length and pollen index. Several methods, dates and threshold temperatures for determining the chill and heat requirements needed to trigger flowering were applied. A diverse APS onset timing sequence was observed for the four cities as Quercus flowers few days in advance in Vigo. The variations observed could be related to differences in the meteorological conditions or the thermal requirements needed for flowering. Thermal requirements differed depending on local climate conditions in the study cities: the lowest values for chilling accumulation were recorded in Vigo and the highest in Lugo, whereas the lowest heat accumulation was achieved in Vigo. Differences in APS trends between cities may reflect variations in weather-related trends. A significant trend towards rising Quercus pollen indices and higher maximum daily mean pollen counts was observed in Ourense, linked to the more marked temperature increase across southern Galicia. A non-uniform trend towards increased temperatures was noted over the study period, particularly in late summer and early autumn in all four study cities. Additionally, an increase in spring temperatures was observed in south-western Galicia.

  20. Neoproterozoic Geography of Baltica: Palaeomagnetic Results From NW Russia

    NASA Astrophysics Data System (ADS)

    Popov, V.; Iosifidi, A.; Tait, J.; Bachtadse, V.; Khramov, A.

    Classical exposures of Upper Vendian sediments exposed to the north of Achangelsk, NW Russia have been the subjected to a detailed palaeomagnetic study. Samples were collected from two localities, at Zimnie Gory along the White Sea Coast, and along the shores of the Zolotica River. More than 600 samples have been subjected to detailed thermal demagnetisation experiments, and up to 3 palaeomagnetic directions can be identified. Two intermediate temperature single-polarity components, labelled compo- nents B and C are isolated. Both magnetisations are synfolding in character yielding maximum k values at 55 and 40 per cent unfolding respectively. Folding occurred in Cretaceous times, and comparison of the resulting palaeopoles with the APWP for Baltica indicates that these directions correspond to remagnetisation events of Or- dovician and Late Permian age. Reasons for the remagnetisation, however, remain elusive. The third and high temperature palaeomagnetic component is identified with dual polarity, passes both the reversal (classification B) and the fold test (99 per cent confidence) and is considered to be primary and Late Vendian in age. The resulting palaeopole for this high temperature component places Baltica in low northern lati- tudes and requires modification of the most recent Apparent Polar Wander Paths for Baltica.

  1. Geochemistry and origin of granitic rocks, Scourian Complex, NW Scotland

    NASA Astrophysics Data System (ADS)

    Pride, C.; Muecke, G. K.

    1982-11-01

    Concordant granite sheets from the granulite facies Scourian Complex, N.W. Scotland exhibit the following features: 1) a common planar fabric with their host pyroxene granulites; 2) the presence of an exsolved ternary feldspar phase; 3) a low-pressure, water-saturated minimum composition; 4) K/Rb ratios (450 1,350) distinctly higher than most upper crustal granites but similar to the surrounding granulites; 5) low absolute concentrations of the rare earth elements (REEs), light REE enrichment, and large positive Eu anomalies. It is proposed that the granite sheets have originated by anatexis of gneisses undergoing granulite facies metamorphism — gneisses that were already essentially dry and depleted in incompatible elements. Their unusual trace element chemistry may be explained by either disequilibrium melting and/or sub-solidus reequilibration of the granite sheets with the surrounding gneisses. Isotopic and trace element data suggest that cross-cutting, potash-rich pegmatites represent reworking of the granite sheets during a later amphibolitization.

  2. Early Pleistocene lake formation and hominin origins in the Turkana-Omo rift

    NASA Astrophysics Data System (ADS)

    Lepre, Christopher J.

    2014-10-01

    Prior research has correlated the formation of Plio-Pleistocene lakes in East Africa to global/regional climate changes and interpreted the lacustrine basins as significant settings of hominin evolution. Paleo-Lake Lorenyang from the Turkana-Omo rift is important to these issues, as its marginal deposits contain some of, if not the earliest currently known specimens of Acheulian stone tools and African Homo erectus. Magnetostratigraphic and sedimentological evidence indicates that the oldest preserved paleo-Lake Lorenyang deposits are dated at 2.148-2.128 Ma and derive from the NW Turkana basin, predating those from the Omo basin by ˜100 kyr and the NE Turkana basin by ˜190 kyr. Apparently, the lake expanded asynchronously in the rift, potentially due to a volcano-tectonic influence on the location of drainage networks, depositional slopes, or topographic elevation differences within and between the basins at the time of flooding. The onset of the lake temporally coincides with the eruption of basalt lava flows dated to 2.2-2.0 Ma that blocked the southeast outlet of the Turkana basin. This provides a plausible mechanism for hydrologic closure and lacustrine basin formation through volcano-tectonic impounding. It also points to a non-climatic cause for the initial formation of paleo-Lake Lorenyang at ˜2.14 Ma. First appearances for African H. erectus (˜1.87 Ma) and Acheulian tools (˜1.76 Ma) in the Turkana-Omo rift postdate the lake's initial formation by about 270 kyr and 380 kyr, respectively. Such timing differences contrast with studies that correlate all three to the 400-kyr-eccentricity maximum at 1.8 Ma. Although the Turkana-Omo rift is just one example, it does provide alternative insights to views that link climate, hominin evolution, and lake formation in East Africa.

  3. Lake retention of manufactured nanoparticles.

    PubMed

    Koelmans, A A; Quik, J T K; Velzeboer, I

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hydraulic loadings covered the widest possible range among existing lakes. Sedimentation accounted for natural colloid as well as suspended solid settling regimes. An ENP-specific mixed sedimentation regime is proposed. This regime combines ENP sedimentation through slow settling with natural colloids from the water column, with faster settling with suspended solids from a selected part of the water column. Although sedimentation data and hydrodynamic concepts as such were not new, their first time combination or application to ENPs shows in which cases lake retention is important for these particles. In combination with ENP emission data, lake retention translates directly into potential risks of ENPs for lake benthic communities.

  4. Lake Garda, Italy

    NASA Image and Video Library

    2001-07-21

    This ASTER image was acquired on July 29, 2000 and covers an area of 30 by 57 km in northern Italy. Lake Garda was formed by glaciers during the last Ice Age, and is Italy's largest lake. Lago di Garda lies in the provinces of Verona, Brescia, and Trento, and is 51 kilometers (32 miles) long and from 3 to 18 kilometers (2 to 11 miles) wide. The Sarca is its chief affluent, and the lake is drained southward by the Mincio, which discharges into the Po River. Many villas are situated on its shores. On the peninsula of Sirmione, at the southern end of the lake, are the ruins of a Roman villa and a castle of the Scaligers, an Italian family of the 16th century. The RIGHT image has the land area masked out, and a harsh stretch was applied to the lake values to display variations in sediment load. Also visible are hundreds of boats and their wakes, criss-crossing the lake. The image is centered at 45.6 degrees north latitude, 10.6 degrees east longitude. http://photojournal.jpl.nasa.gov/catalog/PIA02671

  5. Schistosomiasis in Lake Malawi.

    PubMed

    Cetron, M S; Chitsulo, L; Sullivan, J J; Pilcher, J; Wilson, M; Noh, J; Tsang, V C; Hightower, A W; Addiss, D G

    1996-11-09

    Schistosomiasis is a parasitic infection caused by trematodes. Humans are infected through skin contact with free-swimming cercariae which develop in freshwater snails. Schistosomiasis has been endemic to Malawi for several decades, but the open waters and shores of Lake Malawi have long been thought to be risk-free with regard to schistosomiasis transmission. However, in 1992, two US Peace Corps volunteers developed central nervous system schistosomiasis due to infection with Schistosoma haematobium following recreational water exposure at Cape Maclear on Lake Malawi. In light of these infections, a cross-sectional survey of resident expatriates and visitors to Malawi was subsequently conducted during March-April 1993 to determine the transmission potential and risk for acquiring schistosomiasis in the lake. 305 US citizens and 650 non-US foreign nationals participated in the study. Serological evidence of current or past schistosome infection was identified in 303 subjects. Indeed, seroprevalence was 32% among expatriates whose freshwater exposure was limited to Lake Malawi; S. haematobium antibodies were found in 135 of 141 seropositive specimens. The risk of seropositivity increased with the number of freshwater exposures at Lake Malawi resorts. While many resort areas in the southwestern lake region posed a significant risk, Cape Maclear was the location most strongly associated with seropositivity. Schistosome-infected Bulinus globosus, the snail vector of S. haematobium in Malawi, were found at Cape Maclear and other locations along the lakeshore.

  6. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  7. Overview: Ancient Lake Creede

    USGS Publications Warehouse

    Bethke, Philip M.; Hay, Richard L.

    2000-01-01

    Lake Creede was moderately saline closed-basin lake that developed in the 26.9 Ma Creede caldera in the San Juan Mountains in the southwest Colorado. The volcaniclastic sediments deposited within the late Oligocene lake were first described and named as the Creede Formation by Emmons and Larsen (1923). The lake and its sedimentary fill are of interest first as representatives of a caldera-hosted lake in a silicic volcanic terrane, and second because of the likely involvement of lake fluids or related pore waters in the deposition of the 25 Ma silver and base-metal ores of the Creede mining district north of the Creede caldera (Fig. 1), as proposed Bethke and Rye (1979). Much of the material presented in this volume is based on observation of core samples and on downhole geophysical measurements obtained as part of a U.S. Continental Scientific Drilling Program in the moat of the Creede caldera. These core and downhole studies are supplemented by outcrop studies, some initiated in support of the drilling program (Bethke and Lipman, 1987), and by conceptual studies of the evolution of the Creede caldera and its surrounding landscape. Not surprisingly, not all authors agree on all interpretation. Most disagreements are pointed out in this overview chapter, and may present opportunities for future study.

  8. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  9. Is Lake Chabot Eutrophic?

    NASA Astrophysics Data System (ADS)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

  10. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    EPA Science Inventory

    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  11. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    EPA Science Inventory

    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  12. Glacial lake inventory and lake outburst potential in Uzbekistan.

    PubMed

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-03-16

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m(2). As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions.

  13. Great Lakes, No Clouds

    NASA Image and Video Library

    2017-09-28

    NASA image acquired August 28, 2010 Late August 2010 provided a rare satellite view of a cloudless summer day over the entire Great Lakes region. North Americans trying to sneak in a Labor Day weekend getaway on the lakes were hoping for more of the same. The Great Lakes comprise the largest collective body of fresh water on the planet, containing roughly 18 percent of Earth's supply. Only the polar ice caps contain more fresh water. The region around the Great Lakes basin is home to more than 10 percent of the population of the United States and 25 percent of the population of Canada. Many of those people have tried to escape record heat this summer by visiting the lakes. What they found, according to The Hamilton Spectator, was record-breaking water temperatures fueled by record-breaking air temperatures in the spring and summer. By mid-August, the waters of Lake Superior were 6 to 8°C (11 to 14°F) above normal. Lake Michigan set records at about 4°C (7°F) above normal. The other three Great Lakes – Huron, Erie, and Ontario -- were above normal temperatures, though no records were set. The image was gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite at 1:30 p.m. Central Daylight Time (18:30 UTC) on August 28. Open water appears blue or nearly black. The pale blue and green swirls near the coasts are likely caused by algae or phytoplankton blooms, or by calcium carbonate (chalk) from the lake floor. The sweltering summer temperatures have produced an unprecedented bloom of toxic blue-green algae in western Lake Erie, according to the Cleveland Plain Dealer. NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Mike Carlowicz. Instrument: Aqua - MODIS Click here to see more images from NASA Goddard’s Earth Observatory NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft

  14. Contaminants in American alligator eggs from Lake Apopka, Lake Griffin, and Lake Okeechobee, Florida

    USGS Publications Warehouse

    Heinz, G.H.; Percival, H.F.; Jennings, Michael L.

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A larger sample of eggs was collected in 1985, but only from Lakes Griffin, a lake where eggs were relatively clean, and Apopka, where eggs were most contaminated. In 1985, hatching success of artificially incubated eggs was lower for Lake Apopka, and several organochlorine pesticides were higher than in eggs from Lake Griffin. However, within Lake Apopka, higher levels of pesticides in chemically analyzed eggs were not associated with reduced hatching success of the remaining eggs in the clutch. Therefore, it did not appear that any of the pesticides we measured were responsible for the reduced hatching of Lake Apopka eggs.

  15. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex

    USGS Publications Warehouse

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.

    2006-01-01

    The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry, and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

  16. Big lake records preserved in a little lake's sediment: An example from Silver Lake, Michigan, USA

    USGS Publications Warehouse

    Fisher, T.G.; Loope, W.L.; Pierce, W.; Jol, H.M.

    2007-01-01

    We reconstruct postglacial lake-level history within the Lake Michigan basin using soil stratigraphy, ground-penetrating radar (GPR), sedimentology and 14C data from the Silver Lake basin, which lies adjacent to Lake Michigan. Stratigraphy in nine vibracores recovered from the floor of Silver Lake appears to reflect fluctuation of water levels in the Lake Michigan basin. Aeolian activity within the study area from 3,000 years (cal yr. B.P.) to the present was inferred from analysis of buried soils, an aerial photograph sequence, and GPR. Sediments in and around Silver Lake appear to contain a paleoenvironmental record that spans the entire post-glacial history of the Lake Michigan basin. We suggest that (1) a pre-Nipissing rather than a Nipissing barrier separated Silver Lake basin from the Lake Michigan basin, (2) that the Nipissing transgression elevated the water table in the Silver Lake basin about 6,500 cal yr. B.P., resulting in reestablishment of a lake within the basin, and (3) that recent dune migration into Silver Lake is associated with levels of Lake Michigan.

  17. Long term monitoring system integrated in an elevational gradient in NW Argentina

    NASA Astrophysics Data System (ADS)

    Carilla, J.; Malizia, A.; Osinaga, O.; Blundo, C.; Grau, R.; Malizia, L.; Aráoz, E.

    2013-05-01

    Ecological trends and ranges of variability are poorly known in the tropical and subtropical Andes. Long term studies are powerful tools to detect the response of vegetation dynamics, biodiversity and hydrological cycle to these trends. We present a long term monitoring system in NW Argentinean mountains, including forest permanent plots at different elevations and high elevation grasslands, encompassing more than 3.000 m elevation range. Long term studies include: 1) 66 ha of mountain forest permanent plots along the Yungas elevational gradient from c. 400 to 2500 masl , and latitudinal gradient (22-28S) with 45 plots in mature forests and 28 in secondary forests originated in grazing, agriculture and selective logging. Some of these permanent plots have achieved 20 years of monitoring and all of them are included in the "Red de Bosques Andinos" a network created recently, together with c. 10 institutions and more than 130 (c. 120 ha) forest permanent plots from Argentina to Colombia Andes. 2) Two GLORIA (Global Observation Research Initiative in Alpine Environments) sites, above 4000 masl with more than 170 species recorded, including one re-measurement. This system is included in GLORIA network (www.gloria.ac.at) and in GLORIA Andes (http://www.condesan.org/gloria), and 3) more than 15 satellite monitored high Andean lakes and a wide extension of vegas (75800 ha in Argentinean puna). A digital database is being implemented to organize and provide access to the information generated by these three systems coordinated by the Instituto de Ecología Regional (http://www.iecologia.com.ar). These monitoring data are analyzed together with instrumental and dendrochronological data to describe the dynamics of these ecosystems over an area of 20 million hectares distributed between 22 and 28°S. Some of the most significant results to date include: 1) secondary mountain forests are expanding over grasslands and agriculture lands, and tend to converge toward mature forest

  18. Winter Lake Breezes near the Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Crosman, Erik T.; Horel, John D.

    2016-05-01

    Case studies of lake breezes during wintertime cold air pools in Utah's Salt Lake Valley are examined. While summer breezes originating from the Great Salt Lake are typically deeper, of longer duration, and have higher wind speeds than winter breezes, the rate of inland penetration and cross-frontal temperature differences can be higher during the winter. The characteristics of winter breezes and the forcing mechanisms controlling them (e.g., snow cover, background flow, vertical stability profile, clouds, lake temperature, lake sheltering, and drainage pooling) are more complex and variable than those evident in summer. During the afternoon in the Salt Lake Valley, these lake breezes can lead to elevated pollution levels due to the transport of fine particle pollutants from over the Great Salt Lake, decreased vertical mixing depth, and increased vertical stability.

  19. Crater Lake revealed

    USGS Publications Warehouse

    Ramsey, David W.; Dartnell, Peter; Bacon, Charles R.; Robinson, Joel E.; Gardner, James V.

    2003-01-01

    Around 500,000 people each year visit Crater Lake National Park in the Cascade Range of southern Oregon. Volcanic peaks, evergreen forests, and Crater Lake’s incredibly blue water are the park’s main attractions. Crater Lake partially fills the caldera that formed approximately 7,700 years ago by the eruption and subsequent collapse of a 12,000-foot volcano called Mount Mazama. The caldera-forming or climactic eruption of Mount Mazama drastically changed the landscape all around the volcano and spread a blanket of volcanic ash at least as far away as southern Canada. Prior to the climactic event, Mount Mazama had a 400,000 year history of cone building activity like that of other Cascade volcanoes such as Mount Shasta. Since the climactic eruption, there have been several less violent, smaller postcaldera eruptions within the caldera itself. However, relatively little was known about the specifics of these eruptions because their products were obscured beneath Crater Lake’s surface. As the Crater Lake region is still potentially volcanically active, understanding past eruptive events is important to understanding future eruptions, which could threaten facilities and people at Crater Lake National Park and the major transportation corridor east of the Cascades. Recently, the lake bottom was mapped with a high-resolution multibeam echo sounder. The new bathymetric survey provides a 2m/pixel view of the lake floor from its deepest basins virtually to the shoreline. Using Geographic Information Systems (GIS) applications, the bathymetry data can be visualized and analyzed to shed light on the geology, geomorphology, and geologic history of Crater Lake.

  20. Lake Sarez, Tajikistan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Sarez (top), deep in the Pamir mountains of Tajikistan, was created 90 years ago when a strong earthquake triggered a massive landslide that, in turn, became a huge dam along the Murghob River, now called the Usoi Dam. The resulting lake is perched above surrounding drainages at an elevation greater than 3000m, and is part of the watershed that drains the towering Akademi Nauk Range (see the regional image, lower). The lake is 61 km long and as deep as 500 m, and holds an estimated 17 cubic km of water. The area experiences considerable seismic activity, and scientists fear that part of the right bank may slump into the lake, creating a huge wave that will top over and possibly breach the natural dam. Such a wave would create a catastrophic flood downstream along the Bartang, Panj and Amu Darya Rivers, perhaps reaching all the way to the Aral Sea. Currently, central Asian governments, as well as the World Bank and the UN are monitoring the dam closely, and have proposed gradually lowering the lake level as a preventive measure. More information about the lake is available at the following web sites: Lake Sarez Study group, UN Report, Reliefweb Digital photograph numbers ISS002-E-7771 and ISS002-E-7479 were taken in the spring of 2001 from Space Station Alpha and are provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  1. The Wandering Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In the area at the very far eastern corner of China's Taklimakan Desert, Lop Nor Lake was located up until some years ago. Lop Nor, also called the 'the heart of the heart' of Asia, was the place where the waters of the largest inner basin (i.e., not flowing into the sea) of the world-including the Tarim and Kum-daria Rivers-were collected. Depending on the balance between rainfall water yield and evaporation, both position and size of the lake were strongly variable, thus giving rise to the legend of the Wandering Lake. 'Lop City' was the place where Marco Polo took his last rest before facing the one-year long crossing of the Gobi Desert. Starting from the end of the 19th century, several explorers tried to find the legendary place. One such explorer was Sven Hedin, who was commissioned by the Governor of Nanjing to lead an expedition to find the lake. In 1937, the Swedish explorer published his book entitled The Wandering Lake. Comparing this very precise map from Sven Hedin's book with the above Moderate-resolution Imaging Spectroradiometer (MODIS) false-color image (acquired on October 28, 2001), one can find a faint sign on the soil where the Lop Nor was located. This image, derived using a combination of MODIS' near-infrared and red channels (vegetation in red), shows where the Tarim River waters currently end their flow. The Wandering Lake does not exist anymore. The combination of climate change and human exploitation of water resources for agriculture caused the disappearance of the lake. This image was processed by Telespazio, Earth Observation division, new products development facility in Rome, Italy. The MODIS sensor flies aboard NASA's Terra spacecraft, launched in December 1999. Caption and image courtesy Luca Pietranera, Telespazio, Rome, Italy, based on data from the MODIS Science Team

  2. The Wandering Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In the area at the very far eastern corner of China's Taklimakan Desert, Lop Nor Lake was located up until some years ago. Lop Nor, also called the 'the heart of the heart' of Asia, was the place where the waters of the largest inner basin (i.e., not flowing into the sea) of the world-including the Tarim and Kum-daria Rivers-were collected. Depending on the balance between rainfall water yield and evaporation, both position and size of the lake were strongly variable, thus giving rise to the legend of the Wandering Lake. 'Lop City' was the place where Marco Polo took his last rest before facing the one-year long crossing of the Gobi Desert. Starting from the end of the 19th century, several explorers tried to find the legendary place. One such explorer was Sven Hedin, who was commissioned by the Governor of Nanjing to lead an expedition to find the lake. In 1937, the Swedish explorer published his book entitled The Wandering Lake. Comparing this very precise map from Sven Hedin's book with the above Moderate-resolution Imaging Spectroradiometer (MODIS) false-color image (acquired on October 28, 2001), one can find a faint sign on the soil where the Lop Nor was located. This image, derived using a combination of MODIS' near-infrared and red channels (vegetation in red), shows where the Tarim River waters currently end their flow. The Wandering Lake does not exist anymore. The combination of climate change and human exploitation of water resources for agriculture caused the disappearance of the lake. This image was processed by Telespazio, Earth Observation division, new products development facility in Rome, Italy. The MODIS sensor flies aboard NASA's Terra spacecraft, launched in December 1999. Caption and image courtesy Luca Pietranera, Telespazio, Rome, Italy, based on data from the MODIS Science Team

  3. Lake Sarez, Tajikistan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Sarez (top), deep in the Pamir mountains of Tajikistan, was created 90 years ago when a strong earthquake triggered a massive landslide that, in turn, became a huge dam along the Murghob River, now called the Usoi Dam. The resulting lake is perched above surrounding drainages at an elevation greater than 3000m, and is part of the watershed that drains the towering Akademi Nauk Range (see the regional image, lower). The lake is 61 km long and as deep as 500 m, and holds an estimated 17 cubic km of water. The area experiences considerable seismic activity, and scientists fear that part of the right bank may slump into the lake, creating a huge wave that will top over and possibly breach the natural dam. Such a wave would create a catastrophic flood downstream along the Bartang, Panj and Amu Darya Rivers, perhaps reaching all the way to the Aral Sea. Currently, central Asian governments, as well as the World Bank and the UN are monitoring the dam closely, and have proposed gradually lowering the lake level as a preventive measure. More information about the lake is available at the following web sites: Lake Sarez Study group, UN Report, Reliefweb Digital photograph numbers ISS002-E-7771 and ISS002-E-7479 were taken in the spring of 2001 from Space Station Alpha and are provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  4. Examining indirect effects of lake trout recovery

    EPA Science Inventory

    With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths < 60 m, and siscowet lake trout occupied depths > 60 m...

  5. Examining indirect effects of lake trout recovery

    EPA Science Inventory

    With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths < 60 m, and siscowet lake trout occupied depths > 60 m...

  6. Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia

    NASA Astrophysics Data System (ADS)

    Roningen, J. M.; Burbey, T. J.

    2011-12-01

    Mountain Lake in Giles County, Virginia has a documented history of severe natural lake-level changes involving groundwater seepage that extend over the past 4200 years. Featured in the 1986 movie Dirty Dancing, the natural lake dried up completely in September 2008 and levels have not yet recovered. A hydrogeologic investigation was undertaken in an effort to determine the factors influencing lake level changes. A daily water balance, dipole-dipole electrical resistivity surveying, well logging and chemical sampling have shed light on: 1) the influence of a fault not previously discussed in literature regarding the lake, 2) the seasonal response to precipitation of a forested first-order drainage system in fractured rock, and 3) the possibility of flow pathways related to karst features. Geologic controls on lake level were investigated using several techniques. Geophysical surveys using dipole-dipole resistivity located possible subsurface flowpaths both to and from the lake. Well logs, lineament analysis, and joint sampling were used to assess structural controls on lake hydrology. Major ions were sampled at wells, springs, streams, and the lake to evaluate possible mixing of different sources of water in the lake. Groundwater levels were monitored for correlation to lake levels, rainfall events, and possible seismic effects. The hydrology of the lake was quantified with a water balance on a daily time step. Results from the water balance indicate steady net drainage and significant recharge when vegetation is dormant, particularly during rain-on-snow melt events. The resistivity survey reveals discrete areas that represent flow pathways from the lake, as well as flowpaths to springs upgradient of the lake located in the vicinity of the fault. The survey also suggests that some flowpaths may originate outside of the topographic watershed of the lake. Chemical evidence indicates karst may underlie the lakebed. Historical data suggest that artificial intervention

  7. Recent Increases in Snow Accumulation and Decreases in Sea-Ice Concentration Recorded in a Coastal NW Greenland Ice Core

    NASA Astrophysics Data System (ADS)

    Osterberg, E. C.; Thompson, J. T.; Wong, G. J.; Hawley, R. L.; Kelly, M. A.; Lutz, E.; Howley, J.; Ferris, D. G.

    2013-12-01

    A significant rise in summer temperatures over the past several decades has led to widespread retreat of the Greenland Ice Sheet (GIS) margin and surrounding sea ice. Recent observations from geodetic stations and GRACE show that ice mass loss progressed from South Greenland up to Northwest Greenland by 2005 (Khan et al., 2010). Observations from meteorological stations at the U.S. Thule Air Force Base, remote sensing platforms, and climate reanalyses indicate a 3.5C mean annual warming in the Thule region and a 44% decrease in summer (JJAS) sea-ice concentrations in Baffin Bay from 1980-2010. Mean annual precipitation near Thule increased by 12% over this interval, with the majority of the increase occurring in fall (SON). To improve projections of future ice loss and sea-level rise in a warming climate, we are currently developing multi-proxy records (lake sediment cores, ice cores, glacial geologic data, glaciological models) of Holocene climate variability and cryospheric response in NW Greenland, with a focus on past warm periods. As part of our efforts to develop a millennial-length ice core paleoclimate record from the Thule region, we collected and analyzed snow pit samples and short firn cores (up to 20 m) from the coastal region of the GIS (2Barrel site; 76.9317 N, 63.1467 W) and the summit of North Ice Cap (76.938 N, 67.671 W) in 2011 and 2012, respectively. The 2Barrel ice core was sampled using a continuous ice core melting system at Dartmouth, and subsequently analyzed for major anion and trace element concentrations and stable water isotope ratios. Here we show that the 2Barrel ice core spanning 1990-2010 records a 25% increase in mean annual snow accumulation, and is positively correlated (r = 0.52, p<0.01) with ERA-Interim precipitation. The 2Barrel annual sea-salt Na concentration is strongly correlated (r = 0.5-0.8, p<0.05) with summer and fall sea-ice concentrations in northern Baffin Bay near Thule (Figure 1). We hypothesize that the positive

  8. Stacked uppermost mantle layers within the Slave craton of NW Canada as defined by anisotropic seismic discontinuities

    NASA Astrophysics Data System (ADS)

    Snyder, D. B.

    2007-12-01

    A 20-station seismic array in NW Canada recorded 336 teleseismic events with distribution in back azimuth and epicentral distance sufficient to characterize uppermost mantle discontinuities between depths typical of the Mohorovicic and Lehman discontinuities. Following wave field decomposition, groups of seismograms were source-normalized through simultaneous deconvolution to estimate the near-receiver impulse response and thus detect major discontinuities beneath each seismic station. Stations within the Lac de Gras kimberlite field display an unusually strong negative impulse on the radial component within the NW quadrant and two moderate impulses on the transverse component. Forward modeling of these impulses suggests a mantle layer dipping at 22° to the southeast with a mildly anisotropic upper discontinuity at 120 to 135 km depth and another mildly anisotropic discontinuity at about 170 km depth. Superimposed on these layers is another, stronger anisotropic layer between 110 and 180 km depths that dips to the west. Stations outside of the Lac de Gras field, but within the southeastern Slave craton, display more numerous, but weaker impulses. The most prominent of these occurs at about 150 km depth on the transverse component and has opposite polarity to that observed further north. The prominent negative impulse on the radial component is interpreted to arise from structural- preferred orientation in the form of a stockwork of wehrlite dykes beneath the Lac de Gras field. Interpretation of the other layers in the context of known surface geology as well as xenolith petrology and garnet geochemistry of diamondiferous kimberlites favors previous suggestions that they represent 4000-2900 Ma depleted harzburgite and eclogite layers underthrust from the northwest at 2600 or 1880 Ma. The layer beneath the SE Slave has a similar, but distinct tectonic history of underthrusting associated with the 2635 to 2615 Ma Defeat Suite of plutonism. Taken together, these

  9. A study of petroleum system in Chuhuangkeng anticline, NW Taiwan

    NASA Astrophysics Data System (ADS)

    Yiang, S.; Tsai, L. Y.

    2015-12-01

    Since energy demand is still increasing in the world, the exploration of unconventional fossil fuel becomes more and more important today. Miaoli area of the NW Western Foothill Belt, Taiwan, had been a major oil and gas producing field in the past, important oil/gas producing structures include Tiechenshen, Chinshui and Chuhuangkeng anticline. The reservoir rocks of unconventional resources need to be examined to illustrate the remaining hydrocarbon potential of Chuhuangkeng anticline. A standard evaluation procedure for assessing integrated geochemical parameters can thus be established. In this study, we combine various geochemical parameters including TOC, porosity, Rock-Eval pyrolysis, vitrinite reflectance measurement to assess the HC potential of shale gas reservoirs. The results show that Wuchishan and Mushan Formations possess the best hydrocarbon potential in Chuhuangkeng anticline. The maturation of Wuchishan and Mushan Formations are both in oil window (Ro of Wuchishan formation =1.7% , Ro of Mushan =1.01~1.53% ). The maturation of Shitih Formation barely reached oil window, however the shallower depth and less exploration cost are the advantages of Shitih Formation. Moreover, Wuchishan Formation is a dry gas field and Mushan Formation is a condensate gas field. The results of porosity show that there are secondary porosity existed in Mushan Formation which provides the extra storage space for hydrocarbon. Additionally, Piling Shale is a good cap rock on top of Mushan formation, it further benefits the conservation of oil and gas in Mushan Formation. In conclude, Mushan Formation is the most potential HC target in future shale gas exploration.

  10. The Pliocene-Pleistocene sedimentary tectonic history of NW California

    SciTech Connect

    Stone, L.; Moley, K.; Aalto, K.R. . Dept. of Geology); Renne, P.R. . Berkeley Geochronology Center)

    1993-04-01

    A thick sequence of Late Miocene to Pleistocene sediments thought to represent deposition in a Neogene forearc basin are preserved in the structural basin referred to as the Eel River basin' located offshore of NW California and SE Oregon. The southern portion of this structural basin comes on land in the vicinity of Eureka where the marine and fluvial Wildcat Group is exposed. Basal Wildcat Group sediments are fluvial and littorial. Marine sandstones of the Wildcat Group contain K-spar concentrations of 5.5% and are believed to represent a fresh source. [sup 40]Ar/[sup 39]Ar laser probe analyses of Wildcat Group micas yield dates of 52--57, 66--75, 128.5 and 299--303 Ma. The presence of Idaho detritus throughout the Neogene Wildcat Group indicates that the Klamath Mountains remained low during the Pliocene and early Pleistocene. Younger fluvial sediments in this region contain primarily locally derived detritus indicating local uplift of the Klamath Mountains. To the north, at Crescent City, thin remnants of the near-shore Saint George Formation and the eastern estuarine and fluvial Wimer Formation are lowermost Pliocene in age (5 ma). The presence of the highly erodible Wilmer Formation on uplifted plateaus in an area of extreme rainfall suggest that these sediments represent only the lowermost portion of an originally much thicker sequence. Consequently, the sediments confined to the present day Eel River basin do not represent the lateral extent of the original forearc basin. Sandstones and conglomerates of the Saint George and Wimer Formation indicate a local Klamath provenance derivation.

  11. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    PubMed

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin.

  12. ERUPTIVE VARIABLE STARS AND OUTFLOWS IN SERPENS NW

    SciTech Connect

    Hodapp, Klaus W.; Chini, Rolf; Watermann, Ramon; Lemke, Roland

    2012-01-01

    We study the outflow activity, photometric variability, and morphology of three very young stellar objects in the Serpens NW star-forming region: OO Serpentis, EC 37 (V370 Ser), and EC 53 (V371 Ser). High spatial resolution Keck/NIRC2 laser guide star adaptive optics images obtained in 2007 and 2009 in broadband K and in a narrowband filter centered on the 1-0 S(1) emission line of H{sub 2} allow us to identify the outflows from all three objects. We also present new, seeing-limited data on the photometric evolution of the OO Ser reflection nebula and re-analyze previously published data. We find that OO Ser declined in brightness from its outburst peak in 1995 to about 2003, but that this decline has recently stopped and actually reversed itself in some areas of the reflection nebula. The morphology and proper motions of the shock fronts MHO 2218 near EC 37 suggest that they all originate in EC 37 and that this is an outflow seen nearly along its axis. We identify an H{sub 2} jet emerging from the cometary nebula EC 53. The star illuminating EC 53 is periodically variable with a period of 543 days and has a close-by, non-variable companion at a projected distance of 92 AU. We argue that the periodic variability is the result of accretion instabilities triggered by another very close, not directly observable, binary companion and that EC 53 can be understood in the model of a multiple system developing into a hierarchical configuration.

  13. Timing and Spatial Distribution of Loess in Xinjiang, NW China

    PubMed Central

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess–paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin. PMID:25970617

  14. Mesozooplankton metabolism and feeding in the NW Iberian upwelling

    NASA Astrophysics Data System (ADS)

    Isla, José Alejandro; Ceballos, Sara; Anadón, Ricardo

    2004-09-01

    Mesozooplankton size-fractionated biomass, feeding, and metabolic rates were investigated during a cruise conducted off NW Spain in August 1998. Based on different hydrographic conditions observed throughout the study area (upwelling events nearshore and stratified waters offshore), the sampling area was divided into coastal and oceanic zones. Both phytoplankton and mesozooplankton biomass were higher in the coastal upwelling than in the offshore zone. Size structure analysis shows that the small fraction (200-500 μm) of mesozooplankton was more important than the larger fractions (500-1000 μm and >1000 μm) in the open ocean in terms of both biomass and grazing activity. The relationship between copepod ingestion rate and the concentration of chlorophyll a >5 μm resembled a type II functional response. Saturation occurred at the coastal stations, where copepod gut contents were highest. The grazing impact on both phytoplankton biomass and primary production seemed to be higher offshore (5.7 and 12.9%, respectively) than in upwelled waters (5.2 and 5.2%), although the differences were not statistically significant. Phytoplankton ingestion was enough to fulfil the basal metabolism of mesozooplankton in the upwelling area (102.1% of the minimum carbon requirements met) but not in the offshore (45.9%). Feeding activity and metabolic measurements on mesozooplankton point to a herbivorous food web in the coastal upwelling zone and a multivorous food web in the stratified open oceanic waters. The amount of metabolic end products released by mesozooplankton was higher in the coastal zone, but mesozooplankton played a more important role as nutrient regenerators in the multivorous food web (30.3 and 21.7% of the nitrogen and phosphorus phytoplankton demand accounted for ammonium and phosphate excretion, respectively) than in the herbivorous one (3.8% for ammonium and 2.6% for phosphate).

  15. Deformation and Fluid Flow in the Etendeka Plateau, NW Namibia

    NASA Astrophysics Data System (ADS)

    Salomon, Eric; Koehn, Daniel; Passchier, Cees; Davis, Jennifer; Salvona, Aron; Chung, Peter

    2014-05-01

    We studied deformation bands in sandstone and breccia veins in overlying basalts of the Etendeka Plateau, NW Namibia, regarding their development and history of fluid flow within. The studied deformation bands can be divided into disaggregation bands and cataclastic bands. The former appear to develop in unsorted sandstone, whereas the latter form in well sorted sandstone. We estimated the porosity of the bands and host rock in thin sections using a simple image analysis software (ImageJ). Results show, that no or only a minor decrease in porosity occur in disaggregation bands, while the porosity in cataclastic bands is decreased by up to 82 % with respect to the host rock. These observations are in agreement with results of existing studies (e.g. Fossen et al., 2007). Hence the cataclastic bands form a seal to fluid flow in the host rock, yet it is observed in outcrops that deformation bands can develop into open fractures which in turn increase the permeability of the rock. Breccia veins in the overlying basalts show intense fracturing where the basalt is locally fractured into elongated chips. Mineral precipitation in these breccia veins indicates a hydrothermal origin of the fluids since the precipitates consist of extremely fine-grained quartz aggregates. Secondary mineralization with large crystals indicates that a long-lived fluid circulation through tubular networks was active at a later stage, which eventually sealed the veins completely. We propose that the Etendeka basalts on top of the sandstone formation produced a localized deformation along deformation bands and heated up fluid below the lavas. At a later stage fluid pressures were either high enough to break through the basalt or fracturing due to ongoing extension produced fluid pathways. References Fossen, H., Schultz, R., Shipton, Z. and Mair, K. (2007). Deformation bands in sandstone: a review. J. Geol. Soc., 164, 755-769.

  16. Earthquakes, Uplift, and Landscape Evolution in the NW Himalayas

    NASA Astrophysics Data System (ADS)

    Shahzad, F.; Mahmood, S.; Gloaguen, R.

    2009-05-01

    The terrain between Main Mantle Thrust to Salt Range Thrust in the NW Himalayas has been characterized by surface and subsurface features with variable tectonic activity. These features show relatively variable tectonic activity, existence of blind faults and basement faulting. In the present study, we use seismological and remote sensing analysis backed by field observations to investigate the relationship between earthquakes, uplift, and landscape evolution. We use nonlinear analysis to understand the earthquake dynamics in relation to surface faults and blind faults. The fractal analysis of the seismicity in three subsurface features of the area is used to characterize the roughness of the faults' surface. We find a high fault surface roughness in the Indus Kohistan Seismic Zone (IKSZ). It is concluded that the area is in the process of being uplifted and landscape is evolving. This evolution is further investigated using a set of geomorphological analyses consisting of extracting a drainage network from digital elevation models (DEM). The extracted streams are analysed using to calculate geomorphic indices and relative uplift rates. These analyses were applied on Indus, Swat, Kabul, Kunhar, Kishanganga, Poonch, Jehlum, Swan and Kurram, Kabul Rivers and their associate tributaries. The analyses provide us with the spatial variation of relative uplift based upon specific streams. We found that the Hazara Kashmir Syntaxis and Nanga Parbat Haramosh Massif are subject to a relatively high uplift. It is observed that the neotectonic activities are linearizing the drainage network from meandering pattern. We analyse the complete drainage texture using fractal dimension and lacunarity analysis. The analysis of the fractal dimension (D) employing box counting methods is calculated with a moving window approach and the lower values of D demonstrate the effect of neotectonic activity. The locations with lower but similar D values are further differentiated using

  17. Miocene to recent extension in NW Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Advokaat, Eldert L.; Hall, Robert; White, Lloyd T.; Watkinson, Ian M.; Rudyawan, Alfend; BouDagher-Fadel, Marcelle K.

    2017-10-01

    The Malino Metamorphic Complex (MMC) in the western part of the North Arm of Sulawesi (Indonesia) has previously been suggested to be a metamorphic complex exhumed in the Early - Middle Miocene. This idea was based on limited K-Ar and 40Ar/39Ar age data, but no structural data were presented to provide evidence for the mechanism of exhumation. Here we present new field observations, micro-structural analyses and a revised stratigraphy of NW Sulawesi based on new age data, to provide better constraints on the timing and mechanism of exhumation. The data presented here suggest that the MMC is a metamorphic core complex which underwent lithospheric extension during the Early - Middle Miocene. Although the MMC experienced significant extension, there is no evidence that it was exhumed during this time. There is no contact between the MMC and the Pliocene Ongka Volcanics, contradicting a previously inferred unconformable contact. Pliocene undeformed granitoids intruding the MMC indicate the complex was still at depth during their emplacement. Furthermore, Pliocene and Pleistocene cover sequences do not contain metamorphic detritus. A second phase of extensional uplift was accommodated by brittle faulting from the Late Miocene-Pliocene onwards, during which the MMC was exhumed. This extension is widespread, as indicated by synchronous exhumation of the adjacent Palu Metamorphic Complex in West Sulawesi, and rapid subsidence offshore in Gorontalo Bay. It is linked to northward slab rollback of the southward-subducting Celebes Sea since the Pliocene. GPS data show rapid northward motion of the North Arm of Sulawesi with respect to the Celebes Sea, indicating that this process is ongoing at present day.

  18. Petrography, palynology and depositional environment of Gelibolu coals, NW Turkey

    NASA Astrophysics Data System (ADS)

    Demirtaş, Ferdi; Bozcu, Mustafa; Koşun, Erdal

    2014-05-01

    Upper Oligocene and Miocene coal samples collected from two outcrops in the Gelibolu Peninsula, NW Turkey were analyzed petrographically and palynologically to determine the depositional environment of the coals. Microscopic studies reveal that the studied coal samples from both locations are characterized by high amount of huminite group macerals, ranging from 46 to 78% (mineral-included basis). The prevailing maceral from this group is gelinite (31-65%), it can be easily seen on all studied samples, indicative of high gelification degree of organic matter. Relatively low amount of liptinite (does not exceed 9%) and inertinite (does not exceed 8%) are also observed in the coals. The mineral matter content is variable but generally high, varying from 5 to 37%, as in other Turkish coals and consists mostly of clay minerals, quartz, calcite and pyrite. The mean reflectance values range from 0.502 to 0.564% suggesting that rank of coal is subbituminous (ASTM). The chemical properties of coal including calorific value, volatile matter and fixed carbon content are also in accordance with rank of coal. Facies indices based on maceral ratios (Tissue Preservation Index vs. Gelification Index and ABC ternary diagrams) were used to interpret to depositional environment of coals. Low tissue preservation index (TPI) and high gelification index (GI) values are observed. These indices indicate that the coals deposited in limnic environment. High pH and strongly reducing conditions inferred from the presence of framboidal pyrite and also evidenced by low TPI values. The palynological assembly of the coals dominated by angiosperm pollen and spore, however, gymnosperms were rarely seen. Herbaceous/sedge plants are common in Miocene coal samples.

  19. Density Variations in the NW Star Stream of M31

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W.; Irwin, Mike; Ibata, Rodrigo A.; Dotter, Aaron L.; Chapman, Scott; Fardal, Mark; Ferguson, A. M. N.; Lewis, G. F.; Navarro, Julio F.; Puzia, Thomas H.; Valls-Gabaud, David

    2011-04-01

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10-5. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study. Based on observations obtained with MegaPrime / MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  20. DENSITY VARIATIONS IN THE NW STAR STREAM OF M31

    SciTech Connect

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W. E-mail: richer@astro.ubc.ca

    2011-04-20

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10{sup -5}. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study.

  1. Chemours Pompton Lakes Works Site, Pompton Lakes, NJ

    EPA Pesticide Factsheets

    E.I. DuPont De Nemours & Company is located at 2000 Cannonball Road, Pompton Lakes, New Jersey. The DuPont Pompton Lakes Works site (DuPont) occupies approximately 570 acres of land in Pompton Lakes and Wanaque.

  2. National Lakes Assessment: A Collaborative Survey of the Nation's Lakes

    EPA Science Inventory

    The National Lakes Assessment A Collaborative Survey of the Nation's Lakes presents the results of an unprecedented assessment of the nation’s lakes. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed to provide the pub...

  3. View of Lake Sabrina Dam and dry Lake Sabrina Basin ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Lake Sabrina Dam and dry Lake Sabrina Basin with the upstream side of the outlet structure visible at photo center, view to north-northwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  4. National Lakes Assessment: A Collaborative Survey of the Nation's Lakes

    EPA Science Inventory

    The National Lakes Assessment A Collaborative Survey of the Nation's Lakes presents the results of an unprecedented assessment of the nation’s lakes. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed to provide the pub...

  5. Predicting Lake Depths from Topography to Map Global Lake Volume

    NASA Astrophysics Data System (ADS)

    Holtzman, N.; Pavelsky, T.

    2016-12-01

    The depth of a lake affects its role in climate and biogeochemical cycling. There is a lack of lake depth data due to the difficulty of measuring bathymetry, which impedes the accurate inclusion of lakes in climate models and the assessment of global water resources and carbon storage. However, lake depths can be estimated from land topography, for which remotely-sensed DEM data is available. We develop a simple statistical model to predict lake depth from two explanatory variables: the mean relief above the lake surface of a buffer surrounding the lake, and whether the lake's location was glaciated in the last ice age. The model is based on 328 lakes with known depths, located on all continents but Antarctica, and has an r2 of 0.57. We then apply this model to a set of over 200,000 lakes from the Global Lakes and Wetlands Database to produce global gridded maps of predicted total lake volume and average depth. The realistic depth estimates provided by our model may improve the accuracy of future studies of climate and water resources.

  6. Lake Michigan lake trout PCB model forecast post audit

    EPA Science Inventory

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  7. Lake Michigan lake trout PCB model forecast post audit

    EPA Science Inventory

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  8. 42. Peaks of Otter, Abbott Lake. View across lake to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. Peaks of Otter, Abbott Lake. View across lake to peaks of Outter Lodge, completed in 1964. Construction of the lake got underway in 1964. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  9. The Quaternary Tahoe-Medicine Lake trough: The western margin of the Basin and Range transition, NE California

    SciTech Connect

    Page, W.D. . Geoscience Dept.); Sawyer, T.L. ); Mclaren, M.K.; Savage, W.U.; Wakabayashi, J.

    1993-04-01

    The Tahoe-Medicine Lake trough is a series of small right-stepping, en echelon tectonic depressions that extend 400 km NNW from Lake Tahoe to near the Oregon border. The trough developed since the Miocene, and forms the eastern edge of the Sierra Nevada and southern Cascade Mountains, and the western boundary of the Plumas province and Modoc Plateau, which are transitional to the Basin and Range. The geomorphic expression of the trough indicates late Pleistocene and Holocene fault activity along its length. The continuity of the structure, however, has been masked in places by volcanic deposits that have filled or partly filled the tectonic lows. Moderate historical earthquakes (M5-6) have occurred only along the southern trough. Microearthquakes prominently follow the trough from Lake Tahoe north [omega] Lake Almanor. From there northward, seismicity patterns are predominantly shallow (<5 km) volcanic-related clusters at Mt. Lassen, Medicine Lake, and Tennent and Stephens passes. Geologic and seismicity data indicate that the NW-trending south-central section has a significant component of right-slip, which appears to be related to the Walker Lane shear zone. To the south, the trough is the NNW-striking, 10- to 20-km-wide Tahoe depression, which extends from Lake Tahoe to the Sierra Valley and is partly filled with Quaternary volcanic deposits near Truckee. The escarpment and probable displaced moraines along this section indicate late Pleistocene and possibly Holocene activity. Seismicity is diffuse except in the vicinity of the 1966 Truckee earthquake (M6.0). Northward, from Sierra Valley to American Valley, the trough changes trend to the NW, and is the 6-km-wide Plumas trench, which down-faults the Mehrten Fm. (Miocene to early Pliocene) about 1,000 m.

  10. Real-estate lakes

    USGS Publications Warehouse

    Rickert, David A.; Spieker, Andrew Maute

    1971-01-01

    Since the dawn of civilization waterfront land has been an irresistible attraction to man. Throughout history he has sought out locations fronting on oceans, rivers, and lakes. Originally sought for proximity .to water supply and transportation, such locations are now sought more for their esthetic qualities and for recreation. Usable natural waterfront property is limited, however, and the more desirable sites in many of our urban areas have already been taken. The lack of available waterfront sites has led to the creation of many artificial bodies of water. The rapid suburbanization that has characterized urban growth in America since the end of World War II, together with increasing affluence and le-isure time, has created a ready market for waterfront property. Accordingly, lake-centered subdivisions and developments dot the suburban landscape in many of our major urban areas. Literally thousands of lakes surrounded by homes have materialized during this period of rapid growth. Recently, several "new town" communities have been planned around this lake-centered concept. A lake can be either an asset or a liaoility to a community. A clean, clear, attractively landscaped lake is a definite asset, whereas a weed-choked, foul-smelling mudhole is a distinct liability. The urban environment poses both problems and imaginative opportunities in the development of lakes. Creation of a lake causes changes in all aspects of the environment. Hydrologic systems and ecological patterns are usually most severely altered. The developer should be aware of the potential changes; it is not sufficient merely to build a dam across a stream or to dig a hole in the ground. Development of Gl a successful lake requires careful planning for site selection and design, followed by thorough and cc ntinual management. The purpose of this report is to describe the characteristics of real-estate lakes, to pinpoint potential pmblems, and to suggest possible planning and management guidelines

  11. Cyclostratigraphy of Uppermost Carboniferous-to-Lower Triassic Terrestrial Deposits in Bogda Mountains, NW China - A Potential Astrostratigraphic Proxy Section

    NASA Astrophysics Data System (ADS)

    Yang, W.; Tabor, N. J.; Crowley, J. L.; Miggins, D. P.; Obrist, J.

    2012-12-01

    Lithologic and stratigraphic evidence from the uppermost Carboniferous-Lower Triassic fluvial-lacustrine deposits in the Tarlong-Taodonggou half-graben of southern Bogda Mountains, NW China shows 3 orders of depositional cyclicity. The section is thick (~1,700 m), relatively complete, and well-constrained by radiometric ages, as a potential candidate for Permo-Triassic astrostratigraphy in the mid-latitude of NE Pangea. 10 low-order cycles (LCs) are defined by their dominant depositional environments and prominent cycle boundaries. Upper Gzhelian-mid Sakamarian Lower, Middle, and Upper Daheyan LCs are composed mainly of meandering and braided stream deposits, formed during initial and early rifting. The Upper Daheyan LC contains mature Calcisols, indicating a subhumid-semi-arid climatic change. They were transgressed conformably by lake-margin, deltaic, and profundal deposits of the mid-Sakamarian-Artinskian Lucaogou and Hongyanchi LCs, indicating rapid graben subsidence. Contrasting lithologies suggest highly-fluctuating arid-subhumid conditions at the intermediate and high-order cycle scales. The two LCs are separated by a fluvial-incision and correlative deltaic downlap surface, indicating an uplifting event. Lake regression and fluvial peneplanation at the end of Hongyanchi LC is indicated by fluvial erosion and deposition of the thin (1-10s m) Lower Quanzijie LC, suggesting a tectonic uplift and/or climatic change. The basal two mature Calcisols and top Gleysols of the Upper Quanzijie LC containing fluvial and loess (?) deposits indicate an arid-to-humid climatic change. The two Quanzijie LCs span over Kungurian (?)-Capitanian ages and signify the beginning of late rifting. The humid condition magnified in overlying thick (~800 m) Lopingian-lower Induan Wutonggou LC, composed of deltaic, lake-margin, and meandering stream deposits. The overlying fluvial-lake margin deposits of the Induan Jiucaiyuan LC indicate a combination of tectonic uplift and a climatic

  12. Great Lakes Initiative (GLI) Clearinghouse

    EPA Pesticide Factsheets

    The Great Lakes Initiative Toxicity Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting documents used in developing water quality standards in the Great Lakes watershed.

  13. National Lakes Assessment 2007 Results

    EPA Pesticide Factsheets

    The National Lakes Assessment samples over 1,000 lakes, ponds and reservoirs across the country. Key findings from this assessment in 2007 include the biological condition and most widespread stressors of these waterbodies.

  14. Different Looks for Titan Lakes

    NASA Image and Video Library

    2013-01-08

    Lakes on Saturn moon Titan reflect radio waves in varying ways in this image from NASA Cassini spacecraft. If a lake is fully liquid, it looks dark, but if it is only partially liquid, it looks brighter.

  15. Regional Lake quality patterns: Their relationship to lake conservation and management decisions

    SciTech Connect

    Peterson, S.A.; Hughes, R.M.; Larsen, D.P.; Paulsen, S.G.; Omernik, J.M.

    1996-05-01

    Understanding regional lake quality patterns is important to lake restoration. It puts specific lake conditions into perspective, provides a basis for establishing lake quality goals, identifies lakes most likely to benefit from restoration and forms a framework for assessing restoration success. Two techniques used to characterize regional lake quality patterns are discussed. Combining the two approaches provides an effective means to describe lake regions management goals and restoration success. Case examples illustrate the significant of regional lake quality to specific lake restoration projects.

  16. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    PubMed

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Preliminary Vertical Slip Rate for the West Tahoe Fault from six new Cosmogenic 10Be Exposure Ages of Late Pleistocene Glacial Moraines at Cascade Lake, Lake Tahoe, California

    NASA Astrophysics Data System (ADS)

    Pierce, I. K. D.; Wesnousky, S. G.; Kent, G. M.; Owen, L. A.

    2015-12-01

    The West Tahoe Fault is the primary range bounding fault of the Sierra Nevada at the latitude of Lake Tahoe. It is a N-NW striking, east dipping normal fault that has a pronounced onshore quaternary scarp extending from highway 50 southwest of Meyers, CA to Emerald Bay. At Cascade Lake, the fault cuts and progressively offsets late Pleistocene right lateral moraines. The fault vertically offsets the previously mapped Tahoe moraine ~83 m and the Tioga moraine ~23 m, measured from lidar data. Seventeen samples were collected for 10Be cosmogenic age analysis from boulders on both the hanging and footwalls of the fault along the crests of these moraines.We report here the initial analysis of 6 of these boulders and currently await processing of the remainder. The 10Be exposure ages of 3 boulders each on the younger Tioga and older Tahoe moraines range from 12.7 +/- 1.6 to 20.7 +/- 3.3 ka and 13.3 +/- 2.1 to 72.5 +/- 8.8 ka, respectively. Using the oldest ages as minima, these preliminary results suggest that the slip rate has averaged ~1 mm/yr since the penultimate glaciation, in accord with estimates of previous workers, and place additional bounds on the age of glaciation in the Lake Tahoe basin. The Last Glacial Maxima and penultimate glaciation near Lake Tahoe thus appear to coincide with the Tioga and Tahoe II glaciations of the Eastern Sierra.

  18. ERS-1 SAR backscatter changes associated with ice growing on shallow lakes in Arctic Alaska

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Wakabayashi, H.; Weeks, W. F.

    1993-01-01

    Spatial and temporal backscatter intensity (sigma(sup o)) variations from ice growing on shallow lakes during winter 1991-92 near Barrow, NW Alaska, have been quantified for the first time using ERS-I C-band SAR data acquired at the Alaska SAR Facility. A field and laboratory validation program, including measurements of the thickness and structure-stratigraphy of the ice, indicates that sigma(sup o) values are strongly dependent on whether the ice freezes to the lake bottom, or remains afloat. Backscatter intensity decreases significantly when the ice grounds on the bottom. Strong backscatter from floating ice is attributed to a specular ice-water interface and vertically oriented tubular bubbles. During the spring thaw, backscatter undergoes a reversal; sigma(sup o) values from ice that was grounded increase, while sigma(sup o) values from ice that was afloat decrease. This phenomenon has not previously been reported.

  19. Sanctuaries for lake trout in the Great Lakes

    USGS Publications Warehouse

    Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

    1987-01-01

    Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

  20. The April-June 2007 Trichonis Lake earthquake swarm (W. Greece): New implications toward the causative fault zone

    NASA Astrophysics Data System (ADS)

    Kassaras, I.; Kapetanidis, V.; Karakonstantis, A.; Kaviris, G.; Papadimitriou, P.; Voulgaris, N.; Makropoulos, K.; Popandopoulos, G.; Moshou, A.

    2014-01-01

    On 10 April 2007, three moderate earthquakes with Mw = 4.9-5.1 occurred in the vicinity of Trichonis Lake (W. Greece). A local network composed of 12 three-component digital seismographs was installed in the epicentral area and recorded more than 1600 events. The double-difference algorithm HYPODD, incorporating both catalog and waveform cross-correlation differential travel-time data, was applied for the successful relocation of 1490 earthquakes. The latter led to the distinction of a main NW-SE trending and NE-dipping zone, as well as of three neighboring faults; a conjugate NW-SE striking and SW-dipping marginal fault mapped along the northeastern flanks of the lake; a E-W trending and south-dipping low-angle normal fault, possibly related to the major Agrinio Fault Zone (AFZ), parallel to the northern bank of the lake; a NE-SW striking and NW-dipping normal fault, likely related to a segment of the active Evinos fault, located south of the lake. Calculation of the Coulomb stress induced by the combination of the 1975 Mw = 6.0 event and the three largest events of 10 April 2007 on the inferred structures, reveals that most of the seismicity lies within the "stress-loaded" region, except for the westernmost activity, which probably belongs to the deep part of the AFZ. A total of 178 reliable focal mechanisms were determined by regional and local body-wave modeling (5 largest events) and P-wave first motion polarity data. The types of the obtained focal mechanisms are predominantly normal and strike-slip, however, numerous earthquakes were found to exhibit reverse faulting. Inversion of focal mechanism data showed that the prevailing principal horizontal component σ3 is quite homogeneous throughout the activated area with a roughly NW-SE trend, parallel to the strike of the Hellenides. On the contrary, the compressional field σ1 appears in two patterns: NE-SW trending onshore and NW-SE trending beneath the lake. This apparent rotation of σ1 by 90° reveals a

  1. Michigan: The Great Lakes State

    ERIC Educational Resources Information Center

    McKay, Sandra Lee; La Luzerne-Oi, Sally

    2009-01-01

    Although Michigan is often called the "Wolverine State," its more common nickname is the "Great Lakes State." This name comes from the fact that Michigan is the only state in the United States that borders four of the five Great Lakes. Also referred to as the "Water Wonderland," Michigan has 11,000 additional lakes,…

  2. AirMISR Rogers Lake

    Atmospheric Science Data Center

    2014-04-25

    AirMISR ROGERS LAKE 2001 Project Title:  AirMISR Discipline:  ... ER-2 Spatial Coverage:  Rogers Lake, California (34.75, 35.33)(-118.06, -117.51) Spatial ... Data Readme Files:  Readme Rogers Lake Read Software Files :  IDL Code ...

  3. Red Lake Forestry Greenhouse Program

    Treesearch

    Gloria Whitefeather-Spears

    2002-01-01

    In 1916, The Red Lake Indian Forest Act was created. The Red Lake Band of Chippewa in Minnesota stood alone and refused to consent to allotment. Consequently, The Red Lake Band is the only tribe in Minnesota for which a congressional act was passed to secure a permanent economic foundation for the band and its future.

  4. Viruses in Antarctic lakes

    NASA Technical Reports Server (NTRS)

    Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

    1998-01-01

    Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

  5. Viruses in Antarctic lakes

    NASA Technical Reports Server (NTRS)

    Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

    1998-01-01

    Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

  6. Lake-level frequency analysis for Devils Lake, North Dakota

    USGS Publications Warehouse

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

    An annual lake-volume model and a statistical water mass-balance model were used to estimate future lake-level probabilities for Devils Lake. Comparison of the models indicates upper exceedance levels of the water mass-balance model increase much more rapidly than those of the annual lake-volume model. For simulation year 5, the 99-percent exceedance is 1,417.6 feet above sea level for the annual lake-volume model and 1,423.2 feet above sea level for the water mass-balance model.

  7. Lake Superior, Deluth, MN

    NASA Image and Video Library

    1973-06-22

    SL2-05-454 (22 June 1973) --- This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo. Photo credit: NASA

  8. The Great Lakes whitefish

    USGS Publications Warehouse

    Van Oosten, John; Elliot, Charles

    1942-01-01

    In every one of the Great Lakes- Ontario, Erie, Huron, Michigan, and Superior- the most valuable fishes are declining, and there is no evidence that this trend will be reversed. Under existing conditions of a diversity of regulations that vary between states and between the two countries, and with the present methods of fishing, the Great Lakes fisheries are doomed. This chapter deals with the common whitefish, a valuable species which many believe to be the next that will go unless positive action is forthcoming soon.

  9. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  10. Megasplash at Lake Tahoe

    NASA Astrophysics Data System (ADS)

    Moore, J. G.; Schweickert, R. A.

    2013-12-01

    Backwash from a major ~10 km3 landslide in Lake Tahoe washed away Tioga age (21 ka) moraines (Schweickert, et al 2000; Howle, 2012). Coring in the lake demonstrates a 7700-8000 yr Mt. Mazama ash is widely distributed in lake sediments that overlie the landslide blocks. Moreover, core stratigraphy and radiocarbon ages indicate that all of the sediments cored (to about 3 m depth reaching back 12 ka) were deposited after the landslide (Smith et al., 2013). The age of the landslide is hence constrained at 12-21 ka. Fifteen major subaqueous sand wave channels 2.5 to 10.2 km in length originate from subaqueous delta-terraces at depths of 5-28 m on the margins of the lake. The channels, apparently formed by turbidity currents, are distinctly erosional in their upper part, and transform to deposition aprons in their lower part as they approach the flat lake floor at 500 m depth. The channels contain wave forms (giant ripple marks) convex upstream with maximum wavelengths of 450 m. The lower depositional aprons are surfaced by sand waves convex downstream with maximum wavelengths of 100-300 m. Sand wave convexity mimics the contour of the substrate. The sand wave channel systems are mantled by the post-slide 12 ka sediments and hence have been inactive since that time. These channel-fan structures were apparently produced by backwash from the giant Tahoe landslide, which splashed ~5 km3 of water onto the surrounding countryside thereby lowering lake level by ~10 m. The sediment-charged backwash first deposited the delta-terraces at the lowered lake level and then partly eroded them to generate the sand wave channels, within minutes or hours, while seiche activity resurfaced the delta-terraces. A remarkably similar, though smaller, presently-forming system of turbidity sand wave channels has been imaged at the mouth of the Squamish River in British Columbia (Hughes Clark et al., 2012). The Tahoe splash-induced backwash was briefly equivalent to more than fifteen Squamish

  11. Reevaluation of lake trout and lake whitefish bioenergetics models

    USGS Publications Warehouse

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  12. Maturity schedules of lake trout in Lake Michigan

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.

    1998-01-01

    We determined maturity schedules of male and female lake trout (Salvelinus namaycush) in Lake Michigan from nearshore populations and from an offshore population on Sheboygan Reef, which is located in midlake. Gill nets and bottom trawls were used to catch lake trout in fall 1994 and 1995 from two nearshore sites and Sheboygan Reef. Each lake trout was judged immature or mature, based on visual examination of gonads. Probit analysis, coupled with relative potency testing, revealed that age-at-maturity and length-at-maturity were similar at the two nearshore sites, but that lake trout from the nearshore sites matured at a significantly earlier age than lake trout from Sheboygan Reef. However, length at maturity for the nearshore populations was nearly identical to that for the offshore population, suggesting that rate of lake trout maturation in Lake Michigan was governed by growth rather than age. Half of the lake trout males reached maturity at a total length of 580 mm, whereas half of the females were mature at a length of 640 mm. Over half of nearshore males were mature by age 5, and over half the nearshore females matured by age 6. Due to a slower growth rate, maturity was delayed by 2 years on Sheboygan Reef compared with the nearshore populations. Documentation of this delay in maturation may be useful in deciding stocking allocations for lake trout rehabilitation in Lake Michigan.

  13. Gas exchange on Mono Lake and Crowley Lake, California

    NASA Technical Reports Server (NTRS)

    Wanninkhof, Rik; Ledwell, James R.; Broecker, Wallace S.

    1987-01-01

    Gas exchange coefficients (k) have been determined for freshwater Crowley Lake and saline Mono Lake through the use of a man-made purposefully injected gas, SF6. The concentration decreased from an initial value of 40 to 4 pmol/L for Mono Lake and from 20 to 1 pmol/L for Crowley lake over a period of 6 wks. Wind-speed (u) records from anemometers on the shore of each lake made it possible to determine the relationship between k and u. The average u and k values for the experiment were identical for the two lakes, despite the large chemical differences. It is estimated that, for the u values observed over Mono Lake from July to December 1984, the exchange of CO2 occurred 2.5 times faster than without chemical enhancement. This is a factor of 4 lower than needed to explain the high invasion rate of C-14 produced by nuclear bomb tests.

  14. Gas exchange on Mono Lake and Crowley Lake, California

    NASA Technical Reports Server (NTRS)

    Wanninkhof, Rik; Ledwell, James R.; Broecker, Wallace S.

    1987-01-01

    Gas exchange coefficients (k) have been determined for freshwater Crowley Lake and saline Mono Lake through the use of a man-made purposefully injected gas, SF6. The concentration decreased from an initial value of 40 to 4 pmol/L for Mono Lake and from 20 to 1 pmol/L for Crowley lake over a period of 6 wks. Wind-speed (u) records from anemometers on the shore of each lake made it possible to determine the relationship between k and u. The average u and k values for the experiment were identical for the two lakes, despite the large chemical differences. It is estimated that, for the u values observed over Mono Lake from July to December 1984, the exchange of CO2 occurred 2.5 times faster than without chemical enhancement. This is a factor of 4 lower than needed to explain the high invasion rate of C-14 produced by nuclear bomb tests.

  15. Testing a numerical model for thermokarst lake expansion using morphologic measurements, N. Seward Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Plug, L. J.; Walter, K.; Grosse, G.; Anthony, P.; Smith, M.

    2008-12-01

    The initiation and growth of thermokarst lakes are major factors in the dynamics of ice-rich permafrost lowlands in N. America and Siberia. These landscapes may be a globally-significant influence to past and present climates, because they store Pleistocene and Holocene C and may release it as CH4 to the atmosphere over relatively rapid time-scales. A numerical model that combines thermal processes (heat flow in lake water and permafrost) and geomorphic processes (thaw subsidence and mass movement) is a new and promising tool to investigate the influence of substrate, ground ice content, and climate on the expansion of thermokarst lakes. Models also might be used to predict dynamics of lakes and related biogeochemical processes in coming decades, given anticipated continued warming in high latitude regions. The geomorphic processes that shape natural thaw lake margins include a complicated range of diffusive and advective processes spanning simple creep to more complicated mechanisms including ice wedge melting, thaw slumping, peat-block toppling, turbidity flows, and possibly animal disturbance. The model treats the combined and time-averaged effect of these processes using new and relatively simple algorithms for slope failure and transport distance, which together produce both diffusive and advective behavior. Initial comparisons of the model with measured lake bluffs and bathymetry indicated a good match, but more measurements are needed to fully test and calibrate the model. We measured the bluff morphology and bathymetry of selected lakes of various sizes and age in the Kitluk River, Seward Peninsula, NW Alaska using sonar and DGPS. The region is characterized by continuous permafrost, a highly dissected and dynamic thermokarst landscape, uplands of Late Pleistocene permafrost deposits with high excess ice contents, and a large total volume of permafrost-stored carbon. We drive the model using approximate ground ice conditions for each lake, and compare

  16. Fish Lake, Utah - a promising long core site straddling the Great Basin to Colorado Plateau transition zone

    NASA Astrophysics Data System (ADS)

    Marchetti, D. W.; Abbott, M. B.; Bailey, C.; Wenrich, E.; Stoner, J. S.; Larsen, D. J.; Finkenbinder, M. S.; Anderson, L.; Brunelle, A.; Carter, V.; Power, M. J.; Hatfield, R. G.; Reilly, B.; Harris, M. S.; Grimm, E. C.; Donovan, J.

    2015-12-01

    Fish Lake (~7x1.5 km and 2696 m asl) is located on the Fish Lake Plateau in central Utah. The Lake occupies a NE-striking tectonic graben; one of a suite of grabens on the Plateau that cut 21-26 Ma volcanic rocks. The lake outflows via Lake Creek to the NE where it joins Sevenmile Creek to become the Fremont River, a tributary to the Colorado River. A bathymetric survey reveals a mean depth of 27 m and a max depth of 37.2 m. The lake bottom slopes from NW to SE with the deepest part near the SE wall, matching the topographic expression of the graben. Nearby Fish Lake Hightop (3545 m) was glaciated with an ice field and outlet glaciers. Exposure ages indicate moraine deposition during Pinedale (15-23 ka) and Bull Lake (130-150 ka) times. One outlet glacier at Pelican Canyon deposited moraines and outwash into the lake but the main basin of the lake was never glaciated. Gravity measurements indicate that lake sediments thicken toward the SE side of the lake and the thickest sediment package is modeled to be between 210 and 240 m. In Feb 2014 we collected cores from Fish Lake using a 9-cm diameter UWITECH coring system in 30.5 m of water. A composite 11.2-m-long core was constructed from overlapping 2 m drives that were taken in triplicate to ensure total recovery and good preservation. Twelve 14C ages and 3 tephra layers of known age define the age model. The oldest 14C age of 32.3±4.2 cal ka BP was taken from 10.6 m. Core lithology, CT scans, and magnetic susceptibility (ms) reveal three sediment packages: an organic-rich, low ms Holocene to post-glacial section, a fine-grained, minerogenic glacial section with high ms, and a short section of inferred pre-LGM sediment with intermediate composition. Extrapolating the age model to the maximum estimated sediment thicknesses suggest sediments may be older than 500-700 ka. Thus Fish Lake is an ideal candidate for long core retrieval as it likely contains paleoclimatic records extending over multiple glacial cycles.

  17. Glacimarine sedimentation in Petermann Fjord and Nares Strait, NW Greenland

    NASA Astrophysics Data System (ADS)

    Hogan, Kelly; Jakobsson, Martin; Mayer, Larry; Mix, Alan; Nielsen, Tove; Kamla, Elina; Reilly, Brendan; Heirman, Katrina An; Stranne, Christian; Mohammed, Rezwan; Eriksson, Bjorn; Jerram, Kevin

    2017-04-01

    thinning and acceleration of NW Greenland's marine-terminating outlet glaciers.

  18. Distribution Strategies for Solar and Wind Renewables in NW Europe

    NASA Astrophysics Data System (ADS)

    Smedley, Andrew; Webb, Ann

    2017-04-01

    Whilst the UNFCCC Paris Agreement Climate change was ratified in November, 2016 saw the highest global temperature anomaly on record at 1.2°C above pre-industrial levels. As such there is urgent need to reduce CO2 emissions by a move away from fossil fuels and towards renewable electricity energy technologies. As the principal renewable technologies of solar PV and wind turbines contribute an increasing fraction to the electricity grid, questions of cumulative intermittency and the large-scale geographic distribution of each technology need to be addressed. In this study our initial emphasis is on a calculation of a relatively high spatial resolution (0.1° × 0.1°) daily gridded dataset of solar irradiance data, over a 10 year period (2006-2015). This is achieved by coupling established sources of satellite data (MODIS SSF level2 instantaneous footprint data) to a well-validated radiative transfer model, here LibRadTran. We utilise both a morning and afternoon field for two cloud layers (optical depth and cloud fraction) interpolated to hourly grids, together with aerosol optical depth, topographic height and solar zenith angle. These input parameters are passed to a 5-D LUT of LibRadTran results to construct hourly estimates of the solar irradiance field, which is then integrated to a daily total. For the daily wind resource we rely on the 6 hourly height-adjusted ECMWF ERA-Interim reanalysis wind fields, but separated into onshore, offshore and deep water components. From these datasets of the solar and wind resources we construct 22 different distribution strategies for solar PV and wind turbines based on the long-term availability of each resource. Combining these distributions with the original daily gridded datasets enables each distribution strategy to be then assessed in terms of the day-to-day variability, the installed capacity required to maintain a baseline supply, and the relative proportions of each technology. Notably for the NW European area

  19. An Operational Coastal Forecasting System in Galicia (NW Spain)

    NASA Astrophysics Data System (ADS)

    Balseiro, C. F.; Carracedo, P.; Pérez, E.; Pérez, V.; Taboada, J.; Venacio, A.; Vilasa, L.

    2009-09-01

    The Galician coast (NW Iberian Peninsula coast) and mainly the Rias Baixas (southern Galician rias) are one of the most productive ecosystems in the world, supporting a very active fishing and aquiculture industry. This high productivity lives together with a high human pressure and an intense maritime traffic, which means an important environmental risk. Besides that, Harmful Algae Blooms (HAB) are common in this area, producing important economical losses in aquiculture. In this context, the development of an Operational Hydrodynamic Ocean Forecast System is the first step to the development of a more sophisticated Ocean Integrated Decision Support Tool. A regional oceanographic forecasting system in the Galician Coast has been developed by MeteoGalicia (the Galician regional meteorological agency) inside ESEOO project to provide forecasts on currents, sea level, water temperature and salinity. This system is based on hydrodynamic model MOHID, forced with the operational meteorological model WRF, supported daily at MeteoGalicia . Two grid meshes are running nested at different scales, one of ~2km at the shelf scale and the other one with a resolution of 500 m at the rias scale. ESEOAT (Puertos del Estado) model provide salinity and temperature fields which are relaxed at all depth along the open boundary of the regional model (~6km). Temperature and salinity initial fields are also obtained from this application. Freshwater input from main rivers are included as forcing in MOHID model. Monthly mean discharge data from gauge station have been provided by Aguas de Galicia. Nowadays a coupling between an hydrological model (SWAT) and the hydrodynamic one are in development with the aim to verify the impact of the rivers discharges. The system runs operationally daily, providing two days of forecast. First model verifications had been performed against Puertos del Estado buoys and Xunta de Galicia buoys network along the Galician coast. High resolution model results

  20. Structure of the Rangel alkaline complex (Salta, NW Argentina)

    NASA Astrophysics Data System (ADS)

    Vegas, Nestor; Hongn, Fernando; María Tubía, José; Menegatti, Nilda; Aranguren, Aitor; Rodriguez-Méndez, Lidia

    2017-04-01

    The alcaline complex of the Sierra de Rangel is a Cretaceous granitoid emplaced in the Puna Region, at the province of Salta (NW Argentina). This granitoid spreads over 9 km2 and is elongated following a NE-SW trend. The Rangel complex intrudes Quaternary sediments of the Salinas Grandes salt flat towards the east and Ordovician quartzites and metapelites to the west. There are three main facies in the Rangel granitoid: the easternmost part of the intrusion is composed by sienites that crop out in three hills isolated into the salt flat; the central part of the stock made of alkaline granites and quartz-sienites; and the westernmost side composed by alkaline granites. The available rubidium-strontium ages point out two magmatic pulses: 134±1,6Ma for the granites and quartz-sienites and the sienites of the central and eastern part and 122±1,5 Ma for the alkaline granites of the western border. The most common structure in the host quartzites and metapelites is N55oE-trending schistosity that dips around 60o to the SE. This schistosity is parallel to the axial surface of asymmetric folds with axes plunging to the east. The sharp western contact of the Rangel complex with the host rocks display a N30oE strike and dips around 40o to the SE. This contact is parallel to the intra-magmatic contact between the western and central facies and to the NE-SW elongation of the granitoid. The study of the magnetic fabrics carried on 52 sites of the Rangel complex outline the presence of two sets of tabular intrusions: a main group of overlapping NE-trending sheets that dip to the SE; and a minor group roughly perpendicular to the previous one. The integration of the magnetic fabrics results and the structural data suggest that the former set of intrusions are feeder dykes of the NE-trending sheeted intrusions. Moreover, the radiometric data suggest that the oldest pulse corresponds to the upper part of the granitoid. This fact would imply that the emplacement was controlled by

  1. SAR measurements of coastal features in the NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Redondo, Jose M.; Martinez Benjamin, Juan Jose; Diez, Margarita; Lopez Gonzalez-Nieto, Pilar

    2013-04-01

    The Synthetic Aperture Radar (SAR) is a useful tool to study both marine water dynamics and its pollution, this is relevant near the coastline, where river pollution may be also important. Oil spills and natural slicks are detected with SAR [1-3] to reveal river and vessel pollution as well as the complex eddy and current interaction in the ocean surface near the coastline. In the framework of the ESA and European Union contracts, more than 1000 SAR images of the North-west Mediterranean Sea area taken between December 1996 and December 2008 are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, oil spills and tensioactive slicks that eventually allow predicting the behaviour of different tracers and pollutants in the NW Mediterranean Sea. Thanks to different polarization and intensity levels in satellite imagery can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar as a function of spill parameters, environmental conditions and history of both oil release and weather conditions. (Environmental factors determine [4] spreading, drift and weathering of oil on the sea surface - see: Behaviour oil at sea). Detecting the low contrast patches depends also on the speckle noise which always presents in the image. Application of different filters (available for example in several image processing software (Matlab, Envi, IDL) to the radar data decreases noise level and improves the feature detecting in the image [1] Bezerra, M.O., Diez, M., Medeiros, C., Rodriguez, A., Bahia, E., Sanchez-Arcilla, A. and Redondo, J.M. 1998. Study on the influence of waves on coastal diffusion using image analysis. Applied Scientific Research 59, pp.191-204. [2] Carrillo, A., A., Sanchez,, M

  2. Environmental Magnetic Record of the Harletz (NW Bulgaria) Loess Sequence

    NASA Astrophysics Data System (ADS)

    Lagroix, F.; Jordanova, D.; Jordanova, N.; Rousseau, D. D.; Antoine, P.; Lomax, J.; Fuchs, M.; Melot, L.; Habel, T.; Petrov, P.; Taylor, S. N.; Moine, O.; Debret, M.; Hatte, C.; Till, J. L.

    2016-12-01

    The Harletz loess sequence is located in NW Bulgaria on the western bank of the Ogosta River, a tributary of the Danube. The sequence is exposed on a cliff face carved by the meandering paleo-Ogosta River. A 20 m section, sitting on top of the river's alluvial plain was cleaned and sampled for a multi-disciplinary study. OSL age determinations and field observations suggest that the section spans the last two glacial-interglacial cycles equivalent to marine oxygen isotope stage (MOIS) 7 to the present. High-resolution continuous bulk sampling was carried out to characterise the composition, grain-size and concentration of the magnetic mineral assemblage. In addition to features observed in the field, environmental magnetism data reveal unobserved pedogenic alteration likely related to MOIS 3. Oscillations in, for example, coercivity of remanence, are also detected through MOIS 6 unaltered loess, which may be indicative of two different sources. Both low and high coercivity minerals are by-products of pedogenesis in all paleosols of the Harletz sequence supported by peaks in their respective concentration parameters and superparamagnetic behaviour is detected in most paleosols and the topsoil. Finally, evidence for tephra material is unambiguous at about 12 m depth and likely at about 1.5 m depth. Given the OSL age model for the Harletz sequence (Lomax et al., in preparation), the stratigraphic position of the lower tephra is similar to occurrences in other loess sequences of the region (ex. Mostistea in Romania) and the upper tephra, if confirmed, would correlate temporally with the Campanian tephra. Oriented samples were collected for anisotropy of magnetic susceptibility (AMS) analyses. Triaxial oblate AMS fabrics with horizontal foliation planes are obtained from 15 m depth through the top of MOIS 6 loess. A biaxial oblate AMS fabric with a horizontal foliation plane characterizes the soil complex of the last interglacial. Last glacial loess displays an

  3. Active tectonics coupled to fluvial erosion in the NW Himalaya

    NASA Astrophysics Data System (ADS)

    Vannay, J.-C.; Grasemann, B.; Rahn, M.; Frank, W.; Carter, A.

    2003-04-01

    Both syntaxial extremities of the Himalaya show a spatial correlation between active exhumation of deep crustal rocks and the presence of powerful rivers, the Indus and the Tsangpo-Brahmaputra, cutting across the range two of the deepest gorges on Earth. These features strongly suggests that vigorous fluvial erosion can locally enhance isostatic and tectonic uplift, which in turn contributes to heat advection and weakening of the crust, as well as to maintain steep topographic gradients [Zeitler et al., 2001]. In order to test this positive feedback model, we combined structural and geochronological data to constrain the tectono-thermal evolution along the Sutlej (NW India), the third largest river cross-cutting entirely the Himalaya. The Himalayan crystalline core zone exposed along the Sutlej Valley is composed of two gneiss sheets, that were successively underthrusted and tectonically extruded as a consequence of the foreland-directed propagation of deformation in the Indian plate margin. During Early to Middle Miocene, combined thrusting along the Main Central Thrust (MCT) and extension along the Sangla Detachment induced the rapid exhumation and cooling of the amphibolite facies to migmatitic High Himalayan Crystalline Sequence [Vannay &Grasemann, 2001]. Underthrusting beneath the MCT led to the creation of the amphibolite facies Lesser Himalayan Crystalline Sequence (LHCS). The LHCS cooled rapidly from Late Miocene to Pleistocene, as a consequence of tectonic extrusion controlled by thrusting along the Munsiari Thrust, and extension in the MCT hanging wall. This phase is still active, as indicated by: (1) cooling rates in excess of 100^oC/Myr during the past ˜3 Myr in the LHCS; (2) Holocene neo-tectonic activity; (3) present-day hydrothermal activity testifying to elevated near-surface geothermal gradients; and (4) seismic activity along the Munsiari Thrust. Modelling of fluvial erosion in the Himalaya indicate that the Sutlej Valley corresponds to the main

  4. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    USGS Publications Warehouse

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  5. Temperature Trends in Montane Lakes

    NASA Astrophysics Data System (ADS)

    Melack, J. M.; Sadro, S.; Jellison, R.

    2014-12-01

    Long-term temperature trends in lakes integrate hydrological and meteorological factors. We examine temperature trends in a small montane lake with prolonged ice-cover and large seasonal snowfall and in a large saline lake. Emerald Lake, located in the Sierra Nevada (California), is representative of high-elevation lakes throughout the region. No significant trend in outflow temperature was apparent from 1991to 2012. Snowfall in the watershed accounted for 93% of the variability in average summer lake temperatures. Mono Lake (California) lies in a closed, montane basin and is hypersaline and monomictic or meromictic. Temperature profiles have been collected from 1982 to 2010. In the upper water column, the July-August-September water temperatures increased 0.8-1.0°C over the 29 years. This rate of warming is less than published estimates based on satellite-derived skin temperatures and will discussed in the context of general limnological interpretation of temperature trends.

  6. The Mack Lake fire.

    Treesearch

    Albert J. Simard; Donald A. Haines; Richard W. Blank; John S. Frost

    1983-01-01

    Describes the Mack Lake Fire near Mio, Michigan. Few documented wildfires have exceeded its average spread rate (2 mi/h) and energy release rate (8,800 Btu/ft/sec). The extreme behavior resulted from high winds, low humidity, low fuel moisture and jack pine fuels. Horizontal roll vortices may have contributed to the death of one firefighter.

  7. The People's Lake

    ERIC Educational Resources Information Center

    Carlson, Karen Townsend

    1975-01-01

    Citizen action to stop the disposal of taconite tailings into Lake Superior was unsuccessful when the courts settled in the favor of industry. Although citizen research revealed a form of asbestos, as well as other toxic chemicals in the discharged wastes, company representatives stated that there were no health hazards. (MA)

  8. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Chicago, IL. Great Lakes National Program Office.

    This booklet introduces an environmental curriculum for use in a variety of elementary subjects. The lesson plans provide an integrated approach to incorporating Great Lakes environmental issues into the subjects of history, social studies, and environmental sciences. Each of these sections contains background information, discussion points, and a…

  9. Finger Lakes LPG

    EPA Pesticide Factsheets

    Finger Lakes LPG Storage, LLC; Two Brush Creek Blvd, Suite 200; Kansas City; Missouri 64112 (Applicant) has applied to the U.S. Environmental Protection Agency (EPA) under the provisions of the Safe Drinking Water Act, 42 U.S.C. 300f et. seq (the Act), for

  10. Lake Ontario: Nearshore Variability

    EPA Science Inventory

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  11. Lake Michigan: Nearshore Variability

    EPA Science Inventory

    We conducted a high-resolution survey in the nearshore of Lake Michigan at a 20 meter contour using towed electronic instrumentation. The nearly 1200 km survey was conducted Sep 8-15, 2010. We also conducted six cross-contour tows. Along the survey tracks we sampled fixed stat...

  12. Lake Naivasha, Kenya

    NASA Image and Video Library

    2008-02-29

    If you live in Europe and buy roses, the chance is good that they were grown in Kenya -- specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Image from NASA Terra satellite.

  13. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

    ... mountains surrounding Salt Lake City are renowned for the dry, powdery snow that results from the arid climate and location at the ... should be used with the red filter placed over your left eye. The canyons and peaks of the Uinta and Wasatch Mountains are ...

  14. Quebec: Lake Manicouagan

    Atmospheric Science Data Center

    2013-04-17

    ... kilometers in diameter and is composed of impact-brecciated rock. Glaciation and other erosional processes have reduced the extent of the ... about 5 kilometers. The lake is bounded by erosion-resistant metamorphic and igneous rocks, and shock metamorphic effects are abundant in ...

  15. Lake classification in Vermont

    NASA Technical Reports Server (NTRS)

    Garrison, V.; Bryant, N.

    1981-01-01

    In order to comply with the Federal Clean Water Act and, in so doing, develop a procedure to periodically update the classification, the State of Vermont evaluated the ability of LANDSAT to detect general water quality and specific water quality parameters in Vermont lakes. Unsupervised and supervised classifications as well as regression analyses were used to examine LANDSAT data from Lake Champlain and from four small nearby lakes. Unsupervised and supervised classifications were found to be of somewhat limited value. Regression analyses revealed a good correlation between depth-integrated total phosphorus concentrations and LANDSAT band 4 data (r2= 0.92) and between Secchi disk transparencies and LANDSAT band 4 data (r2 - 0.85). No correlation was found between depth-integrated chlorophyll-a samples and LANDSAT data. Vermont is expanding this LANDSAT evaluation to include the remaining lakes in the state greater than twenty acres and steps are being taken to incorporate LANDSAT into the state's ongoing water quality monitoring programs.

  16. The Great Lakes

    NASA Image and Video Library

    2017-09-27

    NASA image captured March 28, 2011 The Great Lakes Satellite: Terra NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook

  17. The People's Lake

    ERIC Educational Resources Information Center

    Carlson, Karen Townsend

    1975-01-01

    Citizen action to stop the disposal of taconite tailings into Lake Superior was unsuccessful when the courts settled in the favor of industry. Although citizen research revealed a form of asbestos, as well as other toxic chemicals in the discharged wastes, company representatives stated that there were no health hazards. (MA)

  18. Mono Lake, California

    NASA Image and Video Library

    1994-10-01

    STS068-150-020 (30 September-11 October 1994) --- An exceptionally clear, high-contrast view of the desert basins east and south of Mono Lake, California. Light clouds dot the mountain ranges; the clouds were transparent to radar beams from the Space Radar Laboratory 2 (SRL-2) payload.

  19. Poet Lake Crystal Approval

    EPA Pesticide Factsheets

    This September 19, 2016 letter from EPA approves the petition from Poet Biorefining-Lake Crystal, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the RFS

  20. Temperate Lakes Discovered on Titan

    NASA Astrophysics Data System (ADS)

    Vixie, Graham; Barnes, Jason W.; Jackson, Brian; Wilson, Paul

    2012-04-01

    We have discovered two temperate lakes on Titan using Cassini's Visual and Infrared Mapping Spectrometer (VIMS). Three key features help to identify these surface features as lakes: morphology, albedo, and specular reflection. The presence of lakes at the mid-latitudes mean liquid can accumulate and remain stable outside of the poles. We first identify a lake surface by looking for possible shorelines with a lacustrine morphology. Then, we apply a simple atmospheric correction that produces an approximate surface albedo. Next, we prepare cylindrical projection maps of the brightness of the sky as seen from any points on the surface to identify specular reflections. Our techniques can then be applied to other areas, such as Arrakis Planitia, to test for liquid. Currently, all the known lakes on Titan are concentrated at the poles. Lakes have been suggested in the tropic zone by Griffith et al. Our discovery of non-transient, temperate lakes has important implications for Titan's hydrologic cycle. Clouds have been recorded accumulating in the mid-latitudes and areas have been darkened by rainfall but later brightened after evaporation (Turtle et al. 2011). Stable temperate lakes would affect total rainfall, liquid accumulation, evaporation rates, and infiltration. Polaznik Macula (Figure 1) is a great candidate for lake filling, evaporation rates, and stability. References: Griffith, C., et al.: "Evidence for Lakes on Titan's Tropical Surface". AAS/Division for Planetary Sciences Meeting Abstracts #42, Vol. 42, pp. 1077, 2010. Turtle, E. P., et al.: "Rapid and Extensive Surface Changes Near Titan's Equator: Evidence of April Showers". Science, Vol. 331, pp. 1414-, 2011. Figure 1: Polaznik Macula is the large, dark area central to the figure. The encircled dark blue areas represent positively identified lake regions in the T66 flyby. The light blue areas represent lake candidates still under analysis. The green circle marks a non-lake surface feature enclosed by a

  1. The 2000/60/EC Water Framework Directive and the Flooding of the Brown Coal Meirama Open Pit (NW Spain)

    NASA Astrophysics Data System (ADS)

    Delgado, J.; Juncosa, R.

    2009-04-01

    Coal mining in Galicia (NW Spain) has been an important activity which came to an end in December, 2007. Hence, for different reasons, the two large brown coal mines in Galicia (the As Pontes mine, run by ENDESA GENERACIÓN, and the Meirama mine, owned by Lignitos de Meirama, S.A., LIMEISA), have started closure procedures, both of which are considering the flooding of the mine pits to create two large lakes (~8 km2 in As Pontes and ~2 km2 in Meirama). They will be unique in Galicia, a nearly lake-free territory. An important point to consider as regards the flooding of the lignite mine pits in Galicia is how the process of the creation of a body of artificial water will adapt to the strict legal demands put forth in the Water Framework Directive. This problem has been carefully examined by different authors in other countries and it raises the question of the need to adapt sampling surveys to monitor a number of key parameters -priority substances, physical and chemical parameters, biological indicators, etc.- that cannot be overlooked. Flooding, in both cases consider the preferential entrance into the mine holes of river-diverted surface waters, in detriment of ground waters in order to minimize acidic inputs. Although both mines are located in the same hydraulic demarcation (i.e. administrative units that, in Spain, are in charge of the public administration and the enforcement of natural water-related laws) the problems facing the corresponding mine managers are different. In the case of Meirama, the mine hole covers the upper third part of the Barcés river catchment, which is a major source of water for the Cecebre reservoir. That reservoir constitutes the only supply of drinking water for the city of A Coruña (~250.000 inhabitants) and its surrounding towns. In this contribution we will discuss how mine managers and the administration have addressed the uncertainties derived from the implementation of the Water Framework Directive in the particular case of

  2. Microbiology of Lonar Lake and other soda lakes.

    PubMed

    Antony, Chakkiath Paul; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-03-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence.

  3. Microbiology of Lonar Lake and other soda lakes

    PubMed Central

    Paul Antony, Chakkiath; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-01-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

  4. Movements of hatchery-reared lake trout in Lake Superior

    USGS Publications Warehouse

    Pycha, Richard L.; Dryer, William R.; King, George R.

    1965-01-01

    The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed. The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets. Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in 3A? hr. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2-4 miles (3.2-6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated. Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

  5. Lake trout rehabilitation in Lake Erie: a case history

    USGS Publications Warehouse

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  6. Late Miocene Rise of C4 Vegetation in NW Africa from Leaf Wax Biomarkers

    NASA Astrophysics Data System (ADS)

    Rose, C. A.; deMenocal, P. B.; Polissar, P. J.

    2014-12-01

    When and why did NW Africa become dry? The answers to these important questions have proven elusive. Strong climate controls on African vegetation today make knowledge of past changes a valuable proxy for understanding NW Africa's climate evolution. Various lines of geologic and paleobotanical evidence indicate that NW African landscapes changed from more humid conditions in the late Oligocene/early Miocene to arid/hyper-arid environments by the late Pliocene. As proxies for the paleohydrological and paleovegetation signatures of this event, we analyzed leaf wax n-alkane stable isotopes (δDwax and δ13Cwax) at Ocean Drilling Program Site 659 (20°N), offshore West Africa, from 0 - 25 Ma. Between 25 to 10 Ma, n-alkane δ13Cwax values were persistently very low (-31‰) suggesting that C3 vegetation dominated NW African landscapes over this interval. Between 10-7 Ma there is a marked, positive secular δ13Cwax shift (in excess of 4‰) suggesting the initial growth and establishment of C4 Sahel grasslands. δ13Cwax shows a sustained positive trend (>7‰ total) until 1 Ma. The 10-7 Ma date for the establishment of NW African C4 grasslands is earlier than comparable records from South Africa and South Asia. We will also present low-resolution isotope data from equatorial ODP Site 959 (3°N) and compare these data with Site 659 (20°N) to reconstruct the development of the modern vegetation and hydrological gradients in NW Africa over this time span.

  7. Subsurface structural mapping of Northern Nasser Lake region, Aswan, Egypt, using Bouguer data

    NASA Astrophysics Data System (ADS)

    Saleh, Salah

    2011-01-01

    In this study, we attempt to delineate the subsurface structures for the tectonic active region of Northern Nasser Lake using integrated interpretation techniques of gravity data with seismicity. The depths to the gravity sources, and the locations of the contacts of density contrast were estimated. Two methods were used for estimating source depths and contact locations: horizontal gradient (HG) and Euler deconvolution methods. Moreover, power spectral analysis, bandpass and upward continuation techniques were applied to evaluate the shallow and deep seated structures. Shallow depth structures were ranging between 0.30 km and 0.80 km. However, two average levels (interfaces) at depth 3.1 km and 7.2 km below the measuring level were revealed for the intermediate and deep seated structures respectively. Results of Euler deconvolution method suggested that, in the eastern part of the area, the basement could be observed on the ground and has become deeper in the central part. The interpreted structural map reveals that the area is affected by a set of faults trending mainly in the NW, E-W, N-S and NE-SW directions. Actually, this map has confirmed the idea that the intersections between the N-S and E-W striking faults along Nasser Lake area have generated seismic pulses. Moreover, three seismic zones (Z1, Z2 and Z3) are well correlated with the fault trends of the subsurface structures as derived from the horizontal gradient map. The present results suggest that there exist seismically-active fault east of High Dam, passing throughout Aswan reservoir from north to south. This fault is occupying region of high stress values which may generate large earthquakes in future, as it has long extension over several kilometers. Furthermore, the evaluated intruded volcanic bodies are found almost at the intersections between the E-W and NW oriented faults. Finally, the area is dissected by basement uplifts and troughs controlled mainly by the NW-SE faults.

  8. Evolution of alkaline lakes - Lake Van case study

    NASA Astrophysics Data System (ADS)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction < 63 µm assuming that it represents only carbonates precipitating in the water column. Microfossil assemblage consists of three different species of ostracods (Candona spp, Loxoconcha sp, Amnicythere spp.), diatoms, gastropods and bivalves. Brakish-water ostracods, Loxoconcha sp and Amnicythere sp occur more often after 530 ka. Additionaly, Loxoconcha sp is a shallow-water species relaying on plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic

  9. Late Holocene Lake Level Fluctuations at Laguna Arapa, Peru and Connections to Human Demography

    NASA Astrophysics Data System (ADS)

    Hillman, A. L.; Abbott, M. B.; Werne, J. P.; Arkush, E.; Thompson, L. G.; Ferland, T.; Holmes, E.; Puhnaty, C.; Woods, A.

    2016-12-01

    The relationship between variations in hydroclimate and human demography on the Peruvian Altiplano has significant implications for understanding how people in the past have adapted to changes in freshwater resources. To investigate these human-environmental interactions, this project presents a 2,000 year sediment record from Laguna Arapa, a large lake that is <20 km NW of Lake Titicaca. Using sedimentology and stratigraphy as well as a suite of organic geochemical proxies including fecal 5β-stanols and leaf waxes (long chain n-alkanoic acids), we aim to tie together proxies of human population with indicators of regional hydroclimate. Preliminary results of sedimentology and stratigraphy show notable transitions from sand to silt to clay, suggesting rising lake level sequences at 500 and 700 AD. The last 1,300 years of sediment are characterized by alternating layers of organic rich material with abundant charcoal and black inorganic clay, suggesting intermittent periods of aridity and/or anthropogenic fire-setting. These layers are particularly frequent during the Medieval Climate Anomaly, which was characterized by dry and warm conditions. These results agree well with other records of hydroclimate from regional lakes as well as accumulation rate and temperature from the Quelccaya ice cap. Organic geochemical work is currently in progress and shows promise for linking together proxies of human demography with hydroclimate to understand the relationship between human settlement and climate change.

  10. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    USGS Publications Warehouse

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  11. Predicting Maximum Lake Depth from Surrounding Topography

    EPA Science Inventory

    Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

  12. Predicting Maximum Lake Depth from Surrounding Topography

    EPA Science Inventory

    Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

  13. Lake Erie...Take a Bow.

    ERIC Educational Resources Information Center

    Canning, Maureen; Dunlevy, Margie

    This elementary school teaching unit was developed as a part of a series of teaching units that deal with Lake Erie. This unit was developed to enable children to: (1) identify the Great Lakes and pick out Lake Erie on a map; (2) demonstrate knowledge of Lake Erie's origin and geography; (3) list some uses of Lake Erie; and (4) give examples of…

  14. Lake Mead--clear and vital

    USGS Publications Warehouse

    Wessells, Stephen M.; Rosen, Michael

    2013-01-01

    Lake Mead – Clear and Vital” is a 13 minute documentary relating the crucial role of science in maintaining high water quality in Lake Mead. The program was produced coincident with release of the Lakes Mead and Mohave Circular a USGS publication covering past and on-going research in the lakes and tributaries of the Lake Mead National Recreation Area.

  15. Documenting deformation patterns and exhumation across Gianbul Dome, NW India

    NASA Astrophysics Data System (ADS)

    Bowman-Kamaha'o, M.; Lee, J.; Cosca, M. A.

    2012-12-01

    The channel flow model explains the development of the parallel and coeval opposing slip sense structures in the Himalayan orogeny, the southern Tibetan detachment system (STDS) and Main central thrust (MCT). In addition to predicting these two key structures, the channel flow model predicts the development of gneiss domes by several mechanisms. We tested the gneiss dome formation mechanisms by completing detailed deformation, kinematic shear sense, quartz lattice, and deformation temperature analyses, and 40Ar/39Ar thermochronology on middle crustal rocks exposed in Gianbul Dome (GD), NW India. GD comprises high Himalayan crystalline rocks with a sillimanite-grade migmatite core mantled semi-concentrically by lower metamorphic grade kyanite, staurolite, and garnet-bearing units and intruded by prominent mid-Miocene leucogranites. The northeast flank of the dome is buttressed by the Zanskar shear zone, a NE-dipping, down to the northeast normal sense shear zone and the westward continuation of the STDS. The southwest flank of the dome is delineated by the Khanjar shear zone, a SW-dipping down to the southwest normal sense shear zone. A pervasive foliation (S2) exposed across the dome dips ~20-25° NE on the northeast flank of the dome and ~25-30° SW on the southwest flank and includes a down dip stretching lineation (Ls2). Sillimanite, kyanite, staurolite, and garnet grew within the S2 foliation and in places defined the Ls2 lineation indicating that these structures formed at peak-metamorphic conditions (<8 kbar and <800°T, Robyr et al 2006). Quartz and feldspar deformation temperatures across the dome preserve higher temperature textures, 500-700°C, in the core and progressively lower temperature textures, 400-500°C toward the flanks. Contours of deformation temperatures yield a domal geometry, similar to the domed S2 foliation and the temperature conditions provide additional support for the S2 foliation forming at peak metamorphic conditions. Quartz

  16. Characterizing Methane Emission Response to the Past 60 Years of Permafrost Thaw in Thermokarst Lakes

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Walter Anthony, K. M.; Regmi, P.; Engram, M. J.; Wirth, L.; Grosse, G.

    2016-12-01

    In this NASA ABoVE-funded project, we combine geospatial data products derived from airborne and spaceborne remote sensing (RS) data with targeted field observations and modeling in order to quantify ecosystem responses to Arctic and boreal environmental change. Specifically, we quantify methane (CH4) ebullition (bubbling) emissions associated with 60 years of permafrost thaw in thousands of Alaskan and NW Canadian lakes by direct observation with RS systems. To achieve our goals, we have developed statistically-significant models that are using SAR, optical and infrared RS data in order to detect and quantify CH4 ebullition emissions at intra-, whole- and regional-lake scales. We also established a relationship between observed CH4 ebullition and average annual soil organic carbon (SOC) inputs to a handful of Alaskan lakes via thermokarst-margin expansion during recent decades using field data, radiocarbon dating and modeling. Our paper we will provide an overview of the goals, datasets, and methods used for the various components of this project. We will present on (1) the collection of new and synthesis of existing field data on CH4 ebullition, thaw-bulbs and SOC; (2) the analysis of existing data from aerial surveys, SAR and optical RS of CH4 in lake ice; (3) the orthorectification of historic aerial photos for comparison to high-resolution satellite imagery to produce fine-scale regional maps of lake area change, (4) the modelling of permafrost SOC quantities eroded into lakes; (5) the radiocarbon dating of CH4 and SOC, (6) GIS modeling to produce multi-temporal regional maps of historic lake area change, associated CH4 emissions, and permafrost SOC stocks; and (7) outreach to stakeholders at Alaska village and rural community field sites. To demonstrate the scientific relevance of our work we will also showcase a set of research results that we have been able to achieve so far. These will include (1) first regional-scale RS-based estimates of lake-borne CH4

  17. Lake Garda, Italy

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This ASTER image was acquired on July 29, 2000 and covers an area of 30 by 57 km in northern Italy. Lake Garda was formed by glaciers during the last Ice Age, and is Italy's largest lake. Lago di Garda lies in the provinces of Verona, Brescia, and Trento, and is 51 kilometers (32 miles) long and from 3 to 18 kilometers (2 to 11 miles) wide. The Sarca is its chief affluent, and the lake is drained southward by the Mincio, which discharges into the Po River. Many villas are situated on its shores. On the peninsula of Sirmione, at the southern end of the lake, are the ruins of a Roman villa and a castle of the Scaligers, an Italian family of the 16th century. The RIGHT image has the land area masked out, and a harsh stretch was applied to the lake values to display variations in sediment load. Also visible are hundreds of boats and their wakes, criss-crossing the lake.

    The image is centered at 45.6 degrees north latitude, 10.6 degrees east longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for

  18. Sediment Transforms Lake Michigan

    NASA Image and Video Library

    2017-09-27

    NASA image acquired December 17, 2010 In mid-December 2010, suspended sediments transformed the southern end of Lake Michigan. Ranging in color from brown to green, the sediment filled the surface waters along the southern coastline and formed a long, curving tendril extending toward the middle of the lake. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured these natural-color images on December 17, 2010 (top), and December 10, 2010 (bottom). Such sediment clouds are not uncommon in Lake Michigan, where winds influence lake circulation patterns. A scientificpaper published in 2007 described a model of the circulation, noting that while the suspended particles mostly arise from lake-bottom sediments along the western shoreline, they tend to accumulate on the eastern side. When northerly winds blow, two circulation gyres, rotating in opposite directions, transport sediment along the southern shoreline. As the northerly winds die down, the counterclockwise gyre predominates, and the smaller, clockwise gyre dissipates. Clear water—an apparent remnant of the small clockwise gyre—continues to interrupt the sediment plume. George Leshkevich, a researcher with the U.S. National Oceanic and Atmospheric Administration, explains that the wind-driven gyres erode lacustrine clay (very fine lakebed sediment) on the western shore before transporting it, along with re-suspended lake sediments, to the eastern shore. On the eastern side, the gyre encounters a shoreline bulge that pushes it toward the lake’s central southern basin, where it deposits the sediments. The sediment plume on December 17 followed a windy weather front in the region on December 16. NASA image courtesy MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott. Instrument: Aqua - MODIS NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard

  19. Lake Garda, Italy

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This ASTER image was acquired on July 29, 2000 and covers an area of 30 by 57 km in northern Italy. Lake Garda was formed by glaciers during the last Ice Age, and is Italy's largest lake. Lago di Garda lies in the provinces of Verona, Brescia, and Trento, and is 51 kilometers (32 miles) long and from 3 to 18 kilometers (2 to 11 miles) wide. The Sarca is its chief affluent, and the lake is drained southward by the Mincio, which discharges into the Po River. Many villas are situated on its shores. On the peninsula of Sirmione, at the southern end of the lake, are the ruins of a Roman villa and a castle of the Scaligers, an Italian family of the 16th century. The RIGHT image has the land area masked out, and a harsh stretch was applied to the lake values to display variations in sediment load. Also visible are hundreds of boats and their wakes, criss-crossing the lake.

    The image is centered at 45.6 degrees north latitude, 10.6 degrees east longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for

  20. Revising the Limit of the NW Laurentide Ice Sheet: extensive glaciation in NE Beringia

    NASA Astrophysics Data System (ADS)

    Furze, Mark; England, John; Doupé, Jonathan

    2010-05-01

    deglacial sediments associated with marine limit record near-synchronous ice retreat from M'Clure Strait and Dundas Peninsula to north-central Victoria Island ~11.5 ka BP. Along the adjacent coast of Banks Island, deglacial shorelines also record the retreat of Laurentide ice both eastward through M'Clure Strait and southward into the island's interior. The elevation and age (~11.5 ka BP) of deglacial marine limit at both localities are fully compatible with the record of ice retreat on Melville Island. The last retreat of ice from Mercy Bay (northern Banks Island), previously assigned to northward retreat into M'Clure Strait during the Early Wisconsinan, is contradicted by geomorphic evidence for southward retreat into the island's interior during the Late Wisconsinan. This revision of the pattern and age of ice retreat across northern Banks Island results in a significant simplification of the previous Quaternary model. Our observations support the amalgamation of multiple till sheets - previously assigned to at least three pre-Late Wisconsinan glaciations - into the Late Wisconsinan. This revision also removes their formally named marine transgressions and proglacial lakes for which evidence is lacking. An extensive Late Wisconsinan Laurentide Ice Sheet across the western Canadian Arctic is compatible with similar evidence for extensive Laurentide ice entering the Richardson Mountains (Yukon) farther south and with the Innuitian Ice Sheet to the north. Widespread Late Wisconsinan ice, in a region previously thought to be too arid to sustain it, has important implications for modelling of the NW Laurentide Ice Sheet, clarifying the northeast limit of Beringia, understanding the rate of development of periglacial landforms in a landscape rich in buried ice, and identifying the source of ice and sediment delivery to the Arctic Ocean where evidence for former enigmatic ice sheets have been widely reported.

  1. Future volcanic lake research: revealing secrets from poorly studied lakes

    NASA Astrophysics Data System (ADS)

    Rouwet, D.; Tassi, F.; Mora-Amador, R. A.

    2012-04-01

    Volcanic lake research boosted after the 1986 Lake Nyos lethal gas burst, a limnic rather than volcanic event. This led to the formation of the IAVCEI-Commission on Volcanic Lakes, which grew out into a multi-disciplinary scientific community since the 1990's. At Lake Nyos, a degassing pipe is functional since 2001, and two additional pipes were added in 2011, aimed to prevent further limnic eruption events. There are between 150 and 200 volcanic lakes on Earth. Some acidic crater lakes topping active magmatic-hydrothermal systems are monitored continuously or discontinuously. Such detailed studies have shown their usefulness in volcanic surveillance (e.g. Ruapehu, Yugama-Kusatsu-Shiran, Poás). Others are "Nyos-type" lakes, with possible gas accumulation in bottom waters and thus potentially hazardous. "Nyos-type" lakes tend to remain stably stratified in tropical and sub-tropical climates (meromictic), leading to long-term gas build-up and thus higher potential risk. In temperate climates, such lakes tend to turn over in winter (monomictic), and thus liberating its gas charge yearly. We line out research strategies for the different types of lakes. We believe a complementary, multi-disciplinary approach (geochemistry, geophysics, limnology, biology, statistics, etc.) will lead to new insights and ideas, which can be the base for future following-up and monitoring. After 25 years of pioneering studies on rather few lakes, the scientific community should be challenged to study the many poorly studied volcanic lakes, in order to better constrain the related hazard, based on probabilistic approaches.

  2. Genetic diversity of Diporeia in the Great Lakes: comparison of Lake Superior to the other Great Lakes

    EPA Science Inventory

    Abundances of Diporeia have dropped drastically in the Great Lakes, except in Lake Superior, where data suggest that population counts actually have risen. Various ecological, environmental, or geographic hypotheses have been proposed to explain the greater abundance of Lake Supe...

  3. Genetic diversity of Diporeia in the Great Lakes: comparison of Lake Superior to the other Great Lakes

    EPA Science Inventory

    Abundances of Diporeia have dropped drastically in the Great Lakes, except in Lake Superior, where data suggest that population counts actually have risen. Various ecological, environmental, or geographic hypotheses have been proposed to explain the greater abundance of Lake Supe...

  4. Evidence of spring spawning lake trout in Lake Superior

    USGS Publications Warehouse

    Bronte, Charles R.

    1993-01-01

    In 1992, the U. S. Fish and Wildlife Service began research on the life history, population dynamics, and stock delineation of siscowet lake trout Salvelinus namaycush siscowet in Lake Superior. Siscowet were captured with gill nets in 80-150 m of water on 23-26 April 1992 north of the Apostle Islands in western Lake Superior. Of 91 captured siscowets, one male had fully developed testes in nearly ripe condition and one female had eggs running from the vent. This observation represents the earliest dates that lake trout of any morphotype have been found in spawning or near-spawning condition.

  5. Electrical Conductivity Model of the Mantle Lithosphere of the Slave Craton (NW Canada) and its tectonic interpretation in the context of Geochemical Results

    NASA Astrophysics Data System (ADS)

    Lezaeta, P.; Chave, A.; Evans, R.; Jones, A. G.; Ferguson, I.

    2002-12-01

    The Slave Craton, northwestern Canada, contains the oldest known rocks on Earth, with exposed outcrop over an area of about 600x400 km2. The discovery of economic diamondiferous kimberlite pipes during the early 1990s motivated extensive research in the region. Over the last six years, four types of deep-probing magnetotelluric (MT) surveys were conducted within the framework of diverse geoscientific programs, aimed at determining the regional-scale electrical structures of the craton. Two of the surveys involved novel acquisition; one through frozen lake ice along ice roads during winter, and the second deploying ocean-bottom instrumentation from float planes during summer. The latter surveys required one year of recording between summers, thus allowing long period transfer functions that lead to mantle penetration depths of over 300 km. Two-dimensional modeling of the MT data from along the winter road showed the existence of a high conductivity zone at depths of 80-120 km beneath the central Slave craton. This anomalous region is spatially coincident with an ultradepleted harzburgitic layer in the upper mantle that was interpreted by others to be related to a subducted slab emplaced during the mid-Archean. A 3-D electrical conductivity model of the Slave lithosphere has been obtained, by trial and error, to fit the magnetic transfer and MT response functions from the lake experiments. This 3-D model traces the central Slave conductor as a NE-SW oriented mantle structure. Its NE-SW orientation coincides with that of a late fold belt system, with the first phase of craton-wide plutonism at ca 2630-2590 Ma, three-part subdivision of the craton based on SKS results, and with a G10 (garnet) geochemical mantle boundaries. All of these highlight a NE-SW structural grain to the lithospheric mantle of the craton, in sharp contrast to the N-S grain of the crust. Constraints on the depth range and lateral extension of the electrical conductive structure are obtained

  6. Salt Lake City, Utah

    NASA Image and Video Library

    2002-02-07

    The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This simulated natural color image presents a late spring view of north central Utah that includes all of the Olympic sites. The image extends from Ogden in the north, to Provo in the south; and includes the snow-capped Wasatch Mountains and the eastern part of the Great Salt Lake. This image was acquired on May 28, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. http://photojournal.jpl.nasa.gov/catalog/PIA03464

  7. Dongting Lake, China

    NASA Image and Video Library

    2002-09-15

    These images show dramatic change in the water at Dongting Lake in Hunan province, China. A flood crest surged down the Yangtze River in late August of this year, but the embankments made by residents there held. The left image was acquired on September 2, 2002 and shows the extent of the lake. The right image was obtained March 19, 2002 before the flooding began. These images were acquired on September 2, 2002 and March 19, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. http://photojournal.jpl.nasa.gov/catalog/PIA03858

  8. Lake Mead and Drought

    NASA Image and Video Library

    2015-07-20

    Lake Mead supplies water for Arizona, California, Mexico, and other western states. On June 23, the water level fell to 1075 feet, a record low. In 2000, for comparison, the water level was at 1214 feet. A 15-year drought and increased demands for water are to blame for the critical status of the water supply. The difference in 15 years is seen in this pair of images of the western part of Lake Mead, acquired June 21, 2000 by Landsat 7, and June 21, 2015 by ASTER. The images cover an area of 22.5 x 28.5 km, and are located at 36.1 degrees north, 114.7 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19731

  9. Hydrology of Lake County, Florida

    USGS Publications Warehouse

    Knochenmus, Darwin D.; Hughes, G.H.

    1976-01-01

    Lake County includes a 1,150 square-mile area consisting of ridges, uplands, and valleys in central-peninsular Florida. About 32 percent of the county is covered by lakes, swamps, and marshes. Water requirements in 1970 averaged about 54 million gallons per day. About 85 percent of the water was obtained from wells; about 15 percent from lakes. The Floridan aquifer supplies almost all the ground water used in Lake County. Annual recharge to the Floridan aquifer averages about 7 inches over the county; runoff average 8.5 inches. The quality of ground and surface water in Lake County is in general good enough for most uses; however, the poor quality of Floridan-aquifer water in the St. John River Valley probably results from the upward movement of saline water along a fault zone. Surface water in Lake County is usually less mineralized than ground water but is more turbid and colored. (Woodard-USGS)

  10. Modelling lake-water photochemistry: three-decade assessment of the steady-state concentration of photoreactive transients (·OH, CO3(-·) and (3)CDOM(∗)) in the surface water of polymictic Lake Peipsi (Estonia/Russia).

    PubMed

    Minella, Marco; De Laurentiis, Elisa; Buhvestova, Olga; Haldna, Marina; Kangur, Külli; Maurino, Valter; Minero, Claudio; Vione, Davide

    2013-03-01

    Over the last 3-4 decades, Lake Peipsi water (sampling site A, middle part of the lake, and site B, northern part) has experienced a statistically significant increase of bicarbonate, pH, chemical oxygen demand, nitrate (and nitrite in site B), due to combination of climate change and eutrophication. By photochemical modelling, we predicted a statistically significant decrease of radicals ·OH and CO3(-·) (site A, by 45% and 35%, respectively) and an increase of triplet states of chromophoric dissolved organic matter ((3)CDOM(∗); site B, by ∼25%). These species are involved in pollutant degradation, but formation of harmful by-products is more likely with (3)CDOM(∗) than with ·OH. Therefore, the photochemical self-cleansing ability of Lake Peipsi probably decreased with time, due to combined effects of climate change and eutrophication. In different environments (e.g. Lake Maggiore, NW Italy), ecosystem restoration policies had the additional advantage of enhancing sunlight-driven detoxification, suggesting that photochemical self-cleansing would be positively correlated with lake water quality. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Great Lakes Demonstration 2

    DTIC Science & Technology

    2012-06-01

    Representatives from CG Districts 1, 5 , 13, and 17  Enbridge Pipeline, Co.  EPA  National Oceanic and Atmospheric Administration (NOAA)  Observers (CG...distances from the vessel‟s hull. (Figure 5 ) In that configuration, the recovery hose and hydraulic lines dragged across the surface of the nearby...No. CG-D-08-12 2. Government Accession Number 3. Recipient’s Catalog No. 4. Title and Subtitle Great Lakes Demonstration 2 Final Report 5

  12. Angora Fire, Lake Tahoe

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  13. Method for lake restoration

    DOEpatents

    Dawson, Gaynor W.; Mercer, Basil W.

    1979-01-01

    A process for removing pollutants or minerals from lake, river or ocean sediments or from mine tailings is disclosed. Magnetically attractable collection units containing an ion exchange or sorbent media with an affinity for a chosen target substance are distributed in the sediments or tailings. After a period of time has passed sufficient for the particles to bind up the target substances, a magnet drawn through the sediments or across the tailings retrieves the units along with the target substance.

  14. Great Lakes Energy Institute

    SciTech Connect

    Alexander, J. Iwan

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  15. Archaea in Yellowstone Lake.

    PubMed

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E; Inskeep, William P; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R; Nealson, Kenneth

    2011-11-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (~51,000 pyrosequencing reads; V1 and V2 regions) and Sanger sequencing of 200 near-full-length polymerase chain reaction (PCR) clones. Automated classifiers (Ribosomal Database Project (RDP) and Greengenes) were problematic for the 454-FLX reads (wrong domain or phylum), although BLAST analysis of the 454-FLX reads against the phylogenetically placed full-length Sanger sequenced PCR clones proved reliable. Most of the archaeal diversity was associated with vents, and as expected there were differences between the vents and the near-surface photic zone samples. Thaumarchaeota dominated all samples: vent-associated organisms corresponded to the largely uncharacterized Marine Group I, and in surface waters, ~69-84% of the 454-FLX reads matched archaeal clones representing organisms that are Nitrosopumilus maritimus-like (96-97% identity). Importance of the lake nitrogen cycling was also suggested by >5% of the alkaline vent phylotypes being closely related to the nitrifier Candidatus Nitrosocaldus yellowstonii. The Euryarchaeota were primarily related to the uncharacterized environmental clones that make up the Deep Sea Euryarchaeal Group or Deep Sea Hydrothermal Vent Group-6. The phylogenetic parallels of Yellowstone Lake archaea to marine microorganisms provide opportunities to examine interesting evolutionary tracks between freshwater and marine lineages.

  16. Archaea in Yellowstone Lake

    PubMed Central

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E; Inskeep, William P; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R; Nealson, Kenneth

    2011-01-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (∼51 000 pyrosequencing reads; V1 and V2 regions) and Sanger sequencing of 200 near-full-length polymerase chain reaction (PCR) clones. Automated classifiers (Ribosomal Database Project (RDP) and Greengenes) were problematic for the 454-FLX reads (wrong domain or phylum), although BLAST analysis of the 454-FLX reads against the phylogenetically placed full-length Sanger sequenced PCR clones proved reliable. Most of the archaeal diversity was associated with vents, and as expected there were differences between the vents and the near-surface photic zone samples. Thaumarchaeota dominated all samples: vent-associated organisms corresponded to the largely uncharacterized Marine Group I, and in surface waters, ∼69–84% of the 454-FLX reads matched archaeal clones representing organisms that are Nitrosopumilus maritimus-like (96–97% identity). Importance of the lake nitrogen cycling was also suggested by >5% of the alkaline vent phylotypes being closely related to the nitrifier Candidatus Nitrosocaldus yellowstonii. The Euryarchaeota were primarily related to the uncharacterized environmental clones that make up the Deep Sea Euryarchaeal Group or Deep Sea Hydrothermal Vent Group-6. The phylogenetic parallels of Yellowstone Lake archaea to marine microorganisms provide opportunities to examine interesting evolutionary tracks between freshwater and marine lineages. PMID:21544103

  17. Not so Great Lakes?

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, “September of My Years” “Early Bird,” the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  18. Not so Great Lakes?

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, "September of My Years;" "Early Bird," the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  19. Angora Fire, Lake Tahoe

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  20. THOUSAND LAKES WILDERNESS, CALIFORNIA.

    USGS Publications Warehouse

    Till, Alison B.; McHugh, Edward L.

    1984-01-01

    A mineral survey of the Thousand Lakes Wilderness in northern California indicated little promise for the occurrence of mineral resources. Volcanic stone and cinders occur, but similar materials are found in abundance outside the wilderness. The wilderness is in the Cascade Volcanic Province, a setting locally favorable for geothermal resource potential. No geothermal potential was identified in the wilderness; subsurface potential cannot be evaluated without regional studies and drilling.

  1. Where This Occurs: Lakes and Rivers

    EPA Pesticide Factsheets

    Nutrient pollution builds up in our nation's lakes, ponds, and streams. EPA's 2010 National Lakes Assessment found that almost 20 percent of the 50,000 lakes surveyed had been impacted by nitrogen and phosphorus pollution.

  2. Mariano Lake Mine: Legal Documents and Settlements

    EPA Pesticide Factsheets

    Mariano Lake Mine Administrative Order on Consent (AOC) with Statement of Work (SOW) and Mariano Lake Mine Site Settlement Agreement for Engineering Evaluation/Cost Analysis and Statement of Work (SOW) for the Mariano Lake Mine Site.

  3. Landsat analysis of lake quality

    NASA Technical Reports Server (NTRS)

    Scarpace, F. L.; Fisher, L. T.; Holmquist, K. W.

    1979-01-01

    The trophic status of a number of inland lakes in Wisconsin has been assessed. The feasibility of using both photographic and digital representations of Landsat imagery was investigated during the lake classification project. The result of the investigation has been a semi-automatic data acquisition and handling system which, in conjunction with an analytical categorization scheme, can be used to classify all the significant lakes in the state.

  4. Lake Erie Wastewater Management Study.

    DTIC Science & Technology

    1983-06-01

    Lake Erie water quality problem which It has been recognized for many years, dating back this program focused on may be succinctly described Ito...mechanisms fo’ detachment and less. As will be discussed , the costs of achieving fur- transport of sediment and phosphorus to the lake. Fur- ther...WETLANDS FOREST MIXED URBAN OTHER WATER TRANSPORTATION I UTILITIES MISSING are extensively grown in the Lake Erie Basin, especial- measurement by U.S

  5. 10 years of protein crystallography at AR-NW12A beamline

    NASA Astrophysics Data System (ADS)

    Chavas, L. M. G.; Yamada, Y.; Hiraki, M.; Igarashi, N.; Matsugaki, N.; Wakatsuki, S.

    2013-03-01

    The exponential growth of protein crystallography can be observed in the continuously increasing demand for synchrotron beam time, both from academic and industrial users. Nowadays, the screening of a profusion of sample crystals for more and more projects is being implemented by taking advantage of fully automated procedures at every level of the experiments. The insertion device AR-NW12A beamline is one of the five macromolecular crystallography (MX) beamlines at the Photon Factory (PF). Currently the oldest MX beamline operational at the High Energy Accelerator Research Organization (KEK), the end-station was launched in 2001 as part of an upgrade of the PF Advanced Ring. Since its commissioning, AR-NW12A has been operating as a high-throughput beamline, slowly evolving to a multipurpose end-station for MX experiments. The development of the beamline took place about a decade ago, in parallel with a drastic development of protein crystallography and more general synchrotron technology. To keep the beamline up-to-date and competitive with other MX stations in Japan and worldwide, new features have been constantly added, with the goal of user friendliness of the various beamline optics and other instruments. Here we describe the evolution of AR-NW12A for its tenth anniversary. We also discuss the plans for upgrades for AR-NW12A, the future objectives in terms of the beamline developments, and especially the strong desire to open the beamline to a larger user community.

  6. Geomorphological Map of the Lower NW Flank of Hecates Tholus Volcano, Mars

    NASA Astrophysics Data System (ADS)

    de Pablo, M. A.; Centeno, J. D.

    2012-03-01

    We present our 1:100,000-scale geomorphological map of the NW flank of Hecates Tholus volcano, Mars, by the use of CTX images and HRSC-derived DTM. This map will allow us to study in detail the geology and glacial history of this volcano.

  7. 4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W WING, SHOWING THE PILASTERS, TERRA COTTA PANELS, AND THE EGYPTIAN MOTIF DECORATIVE CORNICE ELEMENTS; LOOKING ENE. (Harms) - Veterans Administration Medical Center, Building No. 1, Old State Route 13 West, Marion, Williamson County, IL

  8. 7. 3/4 view of sugar mill looking NW showing entry ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. 3/4 view of sugar mill looking NW showing entry ramp, S and E elevations. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR

  9. 13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW of Amory. St. Louis and San Francisco RR bridge. Steam locomotive and coal train cross bridge on 10 August 1921. Credit: Owned by Jack Donnell, Columbus, Ms., photographer. Copied by Sarcone Photography, Columbus, Ms. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  10. Mineralogical Characteristics of Specimens of a Pseudometeorite ``Fall'' from NW Iran

    NASA Astrophysics Data System (ADS)

    Pourkhorsandi, H.; Mirnejad, H.

    2014-09-01

    In the early hours of October 22, 2011, people of Khameneh town in NW of Iran, noticed sounds of some colliding objects to home roofs and yard floors. Mineralogical investigations revealed the terrestrial and man-made origin of these stony objects.

  11. Chitin nanowhisker (ChNW)-functionalized electrospun PVDF membrane for enhanced removal of Indigo carmine.

    PubMed

    Gopi, Sreerag; Balakrishnan, Preetha; Pius, Anitha; Thomas, Sabu

    2017-06-01

    In this study, an active functional adsorbent membrane developed by combining both hydrophilic bio polymer filler such as chitin nanowhiskers (ChNW) which contains two functional groups and a hydrophobic polymer matrix such as polyvinylidene fluoride (PVDF) using electrospinning technique. Here ChNW were successfully extracted by excluding proteins and mineral and well characterized using FTIR, XRD, SEM and TEM. The optimized combination of PVDF/ChNW (15%:1%) membrane was fabricated and well characterized using SEM, water contact angle and FTIR spectroscopy. There was a remarkable difference in contact angle observed for PVDF/ChNW (22.72°) compared to neat PVDF (93.1°) membrane. Ultimately the membrane used for indigo carmine (IC) adsorption and an enhanced removal efficiency (88.9%) and adsorption capacity (72.6mgg(-1)) were observed compared to neat PVDF. In the future, the overall idea can make leads to various applications such as proteins, virus and hormones adsorption from the contaminated sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Photochemical production of organic matter triplet states in water samples from mountain lakes, located below or above the tree line.

    PubMed

    De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio; Brigante, Marcello; Mailhot, Gilles; Vione, Davide

    2012-08-01

    The production of triplet states (T(*)) of chromophoric dissolved organic matter (CDOM), reacting with the probe molecule 2,4,6-trimethylphenol (TMP) was measured upon irradiation of water samples, taken from lakes located in a mountain area (NW Italy) between 1450 and 2750 m above sea level. The lakes are located below or above the tree line and surrounded by different vegetation types (trees, alpine meadows or exposed rocks). The most photoactive samples belonged to lakes below the tree line and their fluorescence spectra and CDOM optical features suggested the presence of a relatively elevated amount of humic (allochthonous) material. The lowest (negligible) photoactivity was found for a lake surrounded by exposed rocks. Its CDOM showed an important autochthonous contribution (due to in-lake productivity) and considerably higher spectral slope compared to the other samples, suggesting low CDOM molecular weight and/or aromaticity. Among the samples, CDOM photoactivity (measured as the rate of TMP-reactive T(*) photoproduction) decreased with changing vegetation type in the order: trees, meadows, rocks. It could be connected with decreasing contribution from catchment runoff and increasing contribution from autochthonous processes and possibly precipitation.

  13. Magnetic and seismic reflection study of Lake Cheko, a possible impact crater for the 1908 Tunguska Event

    NASA Astrophysics Data System (ADS)

    Gasperini, L.; Cocchi, L.; Stanghellini, C.; Stanghellini, G.; Del Bianco, F.; Serrazanetti, M.; Carmisciano, C.

    2012-05-01

    A major explosion occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2,000 km2 of taiga; pressure and seismic waves detected as far as 1,000 km away; bright luminescence in the night skies of Northern Europe and Central Asia; and other unusual phenomena. This "Tunguska Event" is probably related to the impact with the Earth of a cosmic body that exploded about 5-10 km above ground, releasing in the atmosphere 10-15 Mton of energy. Fragments of the impacting body have never been found, and its nature (comet or asteroid) is still a matter of debate. We report here results from a magnetic and seismic reflection study of a small (˜500 m diameter) lake, Lake Cheko, located about 8 km NW of the inferred explosion epicenter, that was proposed to be an impact crater left by a fragment of the Tunguska Cosmic Body. Seismic reflection and magnetic data revealed a P wave velocity/magnetic anomaly close to the lake center, about 10 m below the lake floor; this anomaly is compatible with the presence of a buried stony object and supports the impact crater origin for Lake Cheko.

  14. Limited Regulation of Lake Erie.

    DTIC Science & Technology

    1983-11-01

    Ontario,, Cedar Point in Ohio, Presque Isle in Pennsylvania and Hamlin in New York. Recreational boating is a significant activity on Lake Erie . Along...RD-Al47 936 LIMITED REGULATION OF LAKE ERIE (U) INTERNATIONAL LAKE i/i ERIE REGULATION STUDY BOARD NOV 83 UNCLASSIFIED F/G 13/2 N lhhhhh..hEmhhI...o lake Erie ’Governmen of 4,- % * L CTE " 84100400 .- Canad Unite Stte INTRNAIONL OIN COMISIO 4WD’ This document hais been ow for public rleoe and so

  15. Great Lakes' regional climate regimes

    NASA Astrophysics Data System (ADS)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  16. Progress toward lake trout restoration in Lake Michigan

    USGS Publications Warehouse

    Holey, Mark E.; Rybicki, Ronald W.; Eck, Gary W.; Brown, Edward H.; Marsden, J. Ellen; Lavis, Dennis S.; Toneys, Michael L.; Trudeau, Tom N.; Horrall, Ross M.

    1995-01-01

    Progress toward lake trout restoration in Lake Michigan is described through 1993. Extinction of the native lake trout fishery by sea lamprey predation, augmented by exploitation and habitat destruction, resulted in an extensive stocking program of hatchery-reared lake trout that began in 1965. Sea lamprey abundance was effectively controlled using selective chemical toxicants. The initial stocking produced a measurable wild year class of lake trout by 1976 in Grand Traverse Bay, but failed to continue probably due to excessive exploitation. The overall lack of successful reproduction lakewide by the late 1970s led to the development and implementation in 1985 of a focused inter-agency lakewide restoration plan by a technical committee created through the Lake Committee structure of the Great Lakes Fishery Commission. Strategies implemented in 1985 by the plan included setting a 40% total mortality goal lakewide, creating two large refuges designed to encompass historically the most productive spawning habitat and protect trout stocked over their home range, evaluating several lake trout strains, and setting stocking priorities throughout the lake. Target levels for stocking in the 1985 Plan have never been reached, and are much less than the estimated lakewide recruitment of yearlings by the native lake trout stocks. Since 1985, over 90% of the available lake trout have been stocked over the best spawning habitat, and colonization of the historically productive offshore reefs has occurred. Concentrations of spawning lake trout large enough for successful reproduction, based on observations of successful hatchery and wild stocks, have developed at specific reefs. Continued lack of recruitment at these specific sites suggests that something other than stotk abundance has limited success. Poor survival of lake trout eggs, assumed to be related to contaminant burden, occurred in the late 1970s and early 1980s, but survival has since increased to equal survival in the

  17. Glacioisostasy and Lake-Level Change at Moosehead Lake, Maine

    USGS Publications Warehouse

    Balco, G.; Belknap, D.F.; Kelley, J.T.

    1998-01-01

    Reconstructions of glacioisostatic rebound based on relative sea level in Maine and adjacent Canada do not agree well with existing geophysical models. In order to understand these discrepancies better, we investigated the lake-level history of 40-km-long Moosehead Lake in northwestern Maine. Glacioisostasy has affected the level of Moosehead Lake since deglaciation ca. 12,500 14C yr B.P. Lowstand features at the southeastern end and an abandoned outlet at the northwestern end of the lake indicate that the lake basin was tilted down to the northwest, toward the retreating ice sheet, by 0.7 m/km at 10,000 14C yr B.P. Water level then rose rapidly in the southeastern end of the lake, and the northwestern outlet was abandoned, indicating rapid relaxation of landscape tilt. Lowstand features at the northwestern end of the lake suggest that the lake basin was tilted to the southeast at ca. 8750 14C yr B.P., possibly as the result of a migrating isostatic forebulge. After 8000 14C yr B.P., water level at the southeastern end was again below present lake level and rose gradually thereafter. We found no evidence suggesting that postglacial climate change significantly affected lake level. The rebound history inferred from lake-level data is consistent with previous interpretations of nearby relative sealevel data, which indicate a significantly steeper and faster-moving ice-proximal depression and ice-distal forebulge than geophysical models predict. ?? 1998 University of Washington.

  18. Lake Powell Half Empty

    NASA Image and Video Library

    2017-09-27

    After 14 years of drought, Lake Powell was at 42 percent of its capacity as of May 20, 2014. The low water levels are evident in these images, which were acquired by the Landsat 8 satellite on May 13, 2014. White bleached rock show where Lake Powell’s shore is when the reservoir is at capacity. It is normal for water levels to fluctuate in the reservoir depending on how much water flows in from snow and rain and how much flows out to meet needs. However, it has been dry in all but three of the past 14 years. At the beginning of 2000, Lake Powell was at 94 percent of capacity. By October 2013 (the beginning of the 2014 water year), water levels had dropped to a low of 50 percent capacity, according to the Bureau of Reclamation, the agency that manages the reservoir. The Earth Observatory’s World of Change shows this annual fluctuation and overall decline. With slightly above average snowpack in the basin that feeds the lake, water levels are expected to rebound to about 51 percent of capacity by October 2014, the end of the water year. While the drop in water levels are worrying for those who generate electricity or use the water for agriculture, the lower water levels may be a draw for recreation. Boaters coming to Lake Powell in the spring of 2014 will find beaches and rock formations that are usually underwater. Bullfrog Bay is the starting point for many boat rentals. The popularity of the spot is evident in the lower image: boats dot the surface of the water, just tiny white flecks at this scale. NASA Earth Observatory image by Robert Simmon, using Landsat data from the U.S. Geological Survey. Caption by Holli Riebeek. Instrument(s): Landsat 8 - OLI Read more: 1.usa.gov/1hck6NX Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by

  19. Lake Charles CCS Project

    SciTech Connect

    Leib, Thomas; Cole, Dan

    2015-06-30

    In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture and Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO2 generated in a large industrial gasification process and sequester the CO2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials

  20. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    SciTech Connect

    Wright, P.J.; Tillitt, D.E.

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  1. Grand Canyon, Lake Powell, and Lake Mead

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A snowfall in the American West provides contrast to the landscape's muted earth tones and indicates changes in topography and elevation across (clockwise from top left) Nevada, Utah, Colorado, New Mexico, Arizona, and California. In Utah, the southern ranges of the Wasatch Mountains are covered in snow, and the Colorado River etches a dark ribbon across the red rock of the Colorado Plateau. In the center of the image is the reservoir created by the Glen Canyon Dam. To the east are the gray-colored slopes of Navaho Mountain, and to the southeast, dusted with snow is the region called Black Mesa. Southwest of Glen Canyon, the Colorado enters the Grand Canyon, which cuts westward through Arizona. At a deep bend in the river, the higher elevations of the Keibab Plateau have held onto snow. At the end of the Grand Canyon lies another large reservoir, Lake Mead, which is formed by the Hoover Dam. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  2. Grand Canyon, Lake Powell, and Lake Mead

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A snowfall in the American West provides contrast to the landscape's muted earth tones and indicates changes in topography and elevation across (clockwise from top left) Nevada, Utah, Colorado, New Mexico, Arizona, and California. In Utah, the southern ranges of the Wasatch Mountains are covered in snow, and the Colorado River etches a dark ribbon across the red rock of the Colorado Plateau. In the center of the image is the reservoir created by the Glen Canyon Dam. To the east are the gray-colored slopes of Navaho Mountain, and to the southeast, dusted with snow is the region called Black Mesa. Southwest of Glen Canyon, the Colorado enters the Grand Canyon, which cuts westward through Arizona. At a deep bend in the river, the higher elevations of the Keibab Plateau have held onto snow. At the end of the Grand Canyon lies another large reservoir, Lake Mead, which is formed by the Hoover Dam. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  3. Holocene lake-level fluctuations of Lake Aricota, Southern Peru

    USGS Publications Warehouse

    Placzek, C.; Quade, Jay; Betancourt, J.L.

    2001-01-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ???2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

  4. Geographical distributions of lake trout strains stocked in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Schaner, Ted

    1996-01-01

    Geographical distributions of lake trout (Salvelinus namaycush) stocked at seven locations in U.S. waters and at four locations in Canadian waters of Lake Ontario were determined from fish caught with gill nets in September in 17 areas of U.S. waters and at 10 fixed locations in Canadian waters in 1986-95. For fish of a given strain stocked at a given location, geographical distributions were not different for immature males and immature females or for mature males and mature females. The proportion of total catch at the three locations nearest the stocking location was higher for mature fish than for immature fish in all 24 available comparisons (sexes combined) and was greater for fish stocked as yearlings than for those stocked as fingerlings in all eight comparisons. Mature fish were relatively widely dispersed from stocking locations indicating that their tendency to return to stocking locations for spawning was weak, and there was no appreciable difference in this tendency among strains. Mature lake trout were uniformly distributed among sampling locations, and the strain composition at stocking locations generally reflected the stocking history 5 to 6 years earlier. Few lake trout moved across Lake Ontario between the north and south shores or between the eastern outlet basin and the main lake basin. Limited dispersal from stocking sites supports the concept of stocking different genetic strains in various parts of the lake with the attributes of each strain selected to match environmental conditions in the portion of the lake where it is stocked.

  5. The near extinction of lake trout in Lake Michigan

    USGS Publications Warehouse

    Eschmeyer, Paul H.

    1957-01-01

    Comparisons in 1949 and 1950 of numbers of legal-sized lake trout caught in large-mesh nets with numbers of small fish taken in chub nets showed that both large and small lake trout declined over the same period, and that by these years the decline may have been greater among small than among legal-sized fish.

  6. HABITAT: LAKE SUPERIOR - STATE OF THE LAKE 2005

    EPA Science Inventory

    This presentation briefly describes the state of research and management in Lake Superior concerning fisheries and their association to habitat. It discusses a general habitat classification for the lake and an increasing interest in the nearshore, summarizing the status of cont...

  7. ARE LAKES GETTING WARMER? REMOTE SENSING OF LARGE LAKE TEMPERATURES

    EPA Science Inventory

    Recent studies (Levitus et al., 2000) suggest a warning of the world ocean over the past 50 years. Freshwater lakes could also be getting warmer but thermal measurements to determine this are lacking. Large lake temperatures are vertically and horizontally heterogeneous and vary ...

  8. Delineation of sympatric morphotypes of lake trout in Lake Superior

    USGS Publications Warehouse

    Moore, Seth A.; Bronte, Charles R.

    2001-01-01

    Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

  9. ARE LAKES GETTING WARMER? REMOTE SENSING OF LARGE LAKE TEMPERATURES

    EPA Science Inventory

    Recent studies (Levitus et al., 2000) suggest a warning of the world ocean over the past 50 years. Freshwater lakes could also be getting warmer but thermal measurements to determine this are lacking. Large lake temperatures are vertically and horizontally heterogeneous and vary ...

  10. Active and Fossil Geothermal Activity at Lake Chapala, Mexico

    NASA Astrophysics Data System (ADS)

    Zârate-del Vall, P.

    2002-12-01

    Geothermal systems are very abundant in the tectonically active zones of the earth's crust and the Citala rift, where Lake Chapala is located, is not the exception. The Lake Chapala basin is characterized by its paleo- and actual geothermal activity that includes: thermal springs, fossil sinter deposits and hydrothermal petroleum manifestations. Thermal springs occur both inside and outside the lake. The spring water in out-shore thermal springs around Lake Chapala is carbonate (Medina-Heredia A, 1986). To the NE area is San Luis Agua Caliente (69°C; ~ 240 mg L-1 [HCO3]1) in the NW at Jocotepec (36°C; ~263mg L-1 [HCO3]-); in the South we find Tuxcueca and Tizap n El Alto (30°C; 193 mg L-1 [HCO3]-). However, there is an exception, the spring water at the San Juan Cosal sector (North), which is sulfate (64-83°C; ~479 mg L-1, [SO4]-2). Examples of in-shore thermal springs are "Los Gorgos" (near South shore) and "El Fuerte" (near East shore and temporary "out-shore" because of actual severe drought); the characterisation of water of this in-shore sites is in progress. On the SE shore and five km NW from Regules village, outcrops a carbonate deposit named "La Calera". This carbonate fossil sinter outcrops 2 km in E-W direction and 600 m in N-S direction and overlays andesitic rock. With a thickness of approximately 5m and a roughly horizontal attitude, the carbonated sinter material is characterized by both massive and banded structure. When massive, it is colored in yellow brownish and grey and elsewhere it shows a pseudo-brecciated structure and when banded, alternated of yellow and dark millimetre bands can be seen; is characterized by vuggy porosity and silica (quartz and chalcedony) vein lets. Under microscope a pseudo-micritic texture is observed; vugs coated by iron oxides, are filled with calcite, and/or quartz, chalcedony and clay minerals. Six samples of carbonate of "La Calera" deposit were analysed for their stable isotopes (LODC-UParis VI). From δ 13

  11. Porewater salinity reveals past lake-level changes in Lake Van, the Earth's largest soda lake.

    PubMed

    Tomonaga, Yama; Brennwald, Matthias S; Livingstone, David M; Kwiecien, Olga; Randlett, Marie-Ève; Stockhecke, Mona; Unwin, Katie; Anselmetti, Flavio S; Beer, Jürg; Haug, Gerald H; Schubert, Carsten J; Sturm, Mike; Kipfer, Rolf

    2017-03-22

    In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about -200 m at about 30 ka BP during the last ice age.

  12. Lake Evaporation: a Model Study

    NASA Astrophysics Data System (ADS)

    Amayreh, Jumah Ahmad

    1995-01-01

    Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evaporation and weather data measurements were used to understand the mechanism of evaporation in the lake, determine lake-related parameters (such as roughness lengths, heat storage, net radiation, etc.), and examine and evaluate existing lake evaporation methods. This enabled the development of a modified and flexible model incorporating the tested methods for hourly and daily best estimates of lake evaporation using nearby simple land-based weather data and, if available, remotely sensed data. Average evaporation from Bear Lake was about 2 mm/day during the summer season (March-October) of this two-year (1993-1994) study. This value reflects the large amount of energy consumed in heating the water body of the lake. Moreover, evaporation from the lake was not directly related to solar radiation. This observation was clear during night time when the evaporation continued with almost the same rate as daytime evaporation. This explains the vital role of heat storage in the lake as the main driving energy for evaporation during night time and day time cloudy sky conditions. When comparing over-lake and nearby land-based weather parameters, land-based wind speed was the only weather parameter that had a significant difference of about 50% lower than over-lake measurements. Other weather parameters were quite similar. The study showed that evaporation from the lake can be accurately estimated using Penman-type equations if related parameters such as net radiation, heat storage, and

  13. The Lake Ohrid SCOPSCO project

    NASA Astrophysics Data System (ADS)

    Wagner, Bernd; Wilke, Thomas; Krastel, Sebastian; Zanchetta, Giovanni; Sulpizio, Roberto; Leng, Melanie J.; Francke, Alexander; Baumgarten, Henrike; Cvetkoska, Aleksandra; Giacco, Biagio; Lacey, Jack H.; Leicher, Niklas; Levkov, Zlatko; Lindhorst, Katja; Reed, Jane M.; Zhang, Xiaosen; Sadori, Laura; Vogel, Hendrik; Wagner-Cremer, Friederike; Wonik, Thomas

    2015-04-01

    The ICDP SCOPSCO project at Lake Ohrid in Macedonia and Albania was one of the most successful lake drilling campaigns worldwide. Drilling took place from April to June 2013 and yielded more than 2000 m of sediments from four different sites in the lake. The maximum penetration was 569 m below lake floor and the overall recovery at all drill sites was > 95 %. Almost two years after the drilling operation, core opening and processing as well as biological and geological analyses are still ongoing. However, most of the cores from the main drill site, the so-called DEEP site in the centre of the lake, are meanwhile opened and reveal a unique record of lake history. The extraordinary quality of seismic, borehole logging and core data allows us to achieve the major goals of the SCOPSCO project. Seismic data, diatoms and coarse-grained sediments in the basal cores indicate that Lake Ohrid had no marine origin, as it was speculated in the past. The data show that Lake Ohrid established in a highly dynamic pull-apart basin with varying fluvial and shallow water conditions. On top of these basal sediments, borehole logging data, XRF scanning data, carbonate, and the amount of organic matter indicate a complete and high resolution succession of glacial / interglacial cycles and interspersed stadials and interstadials. This allows us to determine the establishment of Lake Ohrid by means of chronostratigraphic tuning to about 1.3 to 1.5 Ma ago. Additional, independent age control is given by paleomagnetic data and by numerous tephra layers, which can be correlated with well-dated proximal tephra deposits in Italy. The uppermost 350 m of the sediment record contain more than 30 tephras, which makes the Lake Ohrid record to the rosetta stone of distal Italian tephra deposits in the Balkan region. The unique sediment record of Lake Ohrid is fundamental to obtain crucial information on the overall goal of the SCOPSCO project, i.e. to clarify why Lake Ohrid has one of highest

  14. Forecasting Lake-Effect Snow in the Great Lakes Using NASA Satllite Data

    NASA Technical Reports Server (NTRS)

    Cipullo, Michelle; Molthan, Andrew; Shafer, Jackie; Case, Jonathan; Jedlovec, Gary

    2011-01-01

    This slide presentation reviews the forecast of the lake effect snow in the Great Lakes region using models and infrared estimates of Great Lake Surface Temperatures (GLSTs) from the MModerate Resolution Imaging Spectroradiometer (MODIS) instrument on Terra and Aqua satellites, and other satellite data. This study analyzes Lake Erie and Lake Ontario which produce storm total snowfall ranged from 8-18 inches off of Lake Ontario and 10-12 inches off of Lake Erie for the areas downwind.

  15. Feeding competition between larval lake whitefish and lake herring

    USGS Publications Warehouse

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

    The potential for competition for food between larval lake whitefish (Coregonus clupeaformis) and lake herring (C. artedi) 1- to 8-wk of age was explored in a series of 1-h laboratory feeding studies. Feeding started at 2-wk post-hatch. Learning and fish size appear to be more important than prey density at the onset of feeding. Species differed in their feeding behavior and consumption noticeably by 5-wk and substantially by 8-wk. Lake whitefish generally were more aggressive foragers than lake herring, attacking and capturing more prey. At high plankton density at 8-wk, lake herring feeding was depressed in mixed-fish treatments. This difference in competitive food consumption between the two coregonids occurs at a critical life stage, and when combined with other biotic and abiotic factors, may have a significant impact on recruitment.

  16. PCB concentrations in lake trout (Salvelinus namaycush) are correlated to habitat use and lake characteristics.

    PubMed

    Guildford, S J; Muir, D C G; Houde, M; Evans, M S; Kidd, K A; Whittle, D M; Drouillard, K; Wang, X; Anderson, M R; Bronte, C R; Devault, D S; Haffner, D; Payne, J; Kling, H J

    2008-11-15

    This study considers the importance of lake trout habitat as a factor determining persistent organochlorine (OC) concentration. Lake trout is a stenothermal, cold water species and sensitive to hypoxia. Thus, factors such as lake depth, thermal stratification, and phosphorus enrichment may determine not only which lakes can support lake trout but may also influence among-lake variability in lake trout population characteristics including bioaccumulation of OCs. A survey of 23 lakes spanning much of the natural latitudinal distribution of lake trout provided a range of lake trout habitat to test the hypothesis that lake trout with greater access to littoral habitat for feeding will have lower concentrations of OCs than lake trout that are more restricted to pelagic habitat. Using the delta13C stable isotope signature in lake trout as an indicator of influence of benthic littoral feeding, we found a negative correlation between lipid-corrected delta13C and sigmaPCB concentrations supporting the hypothesis that increasing accessto littoral habitat results in lower OCs in lake trout. The prominence of mixotrophic phytoplankton in lakes with more contaminated lake trout indicated the pelagic microbial food web may exacerbate the biomagnification of OCs when lake trout are restricted to pelagic feeding. A model that predicted sigmaPCB in lake trout based on lake area and latitude (used as proximate variables for proportion of littoral versus pelagic habitat and accessibility to littoral habitat respectively) explained 73% of the variability in sigmaPCBs in lake trout in the 23 lakes surveyed.

  17. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    SciTech Connect

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  18. Surface seiches in Flathead Lake

    NASA Astrophysics Data System (ADS)

    Kirillin, G.; Lorang, M. S.; Lippmann, T. C.; Gotschalk, C. C.; Schimmelpfennig, S.

    2014-12-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion and bottom sediment transport and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss the lake management problems related to of the spatial seiche distribution, such as shoreline erosion, floods and transport of sediments and invasive species in Flathead Lake.

  19. Surface seiches in Flathead Lake

    NASA Astrophysics Data System (ADS)

    Kirillin, G.; Lorang, M. S.; Lippmann, T. C.; Gotschalk, C. C.; Schimmelpfennig, S.

    2015-06-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion, and bottom sediment transport, and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes, we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin to the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake, including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss lake management problems related to the spatial seiche distribution, such as shoreline erosion, floods, and transport of sediments and invasive species in Flathead Lake.

  20. The Great Lakes Food Web.

    ERIC Educational Resources Information Center

    Baker, Marjane L.

    1997-01-01

    Presents a play for students in grades four to nine that incorporates the scientific names, physical characteristics, feeding habits, interactions, and interdependence of the plants and animals that make up the Great Lakes food web to facilitate the learning of this complex system. Includes a Great Lakes food web chart. (AIM)

  1. The Great Lakes Food Web.

    ERIC Educational Resources Information Center

    Baker, Marjane L.

    1997-01-01

    Presents a play for students in grades four to nine that incorporates the scientific names, physical characteristics, feeding habits, interactions, and interdependence of the plants and animals that make up the Great Lakes food web to facilitate the learning of this complex system. Includes a Great Lakes food web chart. (AIM)

  2. An urban lake remediation experiment

    SciTech Connect

    Castelli, S.E.; Gardner, K.H.; Jennings, A.A.

    1998-07-01

    Circumstances provided the opportunity to study a small urban lake as the surrounding municipalities attempted to improve its aesthetic quality by dredging. This manuscript focuses primarily on the sediments in the system: accumulation rates, the expected dynamics of the lake bed drying process, and the influence of the sediments on water quality.

  3. Pyramid Lake Renewable Energy Project

    SciTech Connect

    John Jackson

    2008-03-14

    The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

  4. NATIONAL LAKE ASSESSMENT MONITORING DESIGN

    EPA Science Inventory

    The USEPA designed the National Lake Assessment in 2005-6 with field sampling being completed in 2007. The objective of the assessment is to estimate the ecological condition of lakes and reservoirs nationally. The objective of this paper is to describe the national survey desi...

  5. "Lake Woebegone," Twenty Years Later

    ERIC Educational Resources Information Center

    Cannell, John Jacob

    2006-01-01

    Almost 20 years ago, the author wrote--and then privately published--the two "Lake Woebegone" reports, named after Garrison Keillor's mythical Minnesota town where "all the women are strong, all the men are good-looking, and all the children are above average." The first "Lake Woebegone" report documented that all 50 states were testing above the…

  6. NATIONAL LAKE ASSESSMENT MONITORING DESIGN

    EPA Science Inventory

    The USEPA designed the National Lake Assessment in 2005-6 with field sampling being completed in 2007. The objective of the assessment is to estimate the ecological condition of lakes and reservoirs nationally. The objective of this paper is to describe the national survey desi...

  7. Planktonic diatoms of Lake Ontario

    USGS Publications Warehouse

    Reinwand, Jerry F.

    1969-01-01

    The major species of diatoms in surface collections from Lake Ontario in September 1964 were Asterionella formosa, Fragilaria crotonensis, and Tabellaris fenestrata. Dominant species in the deep-water samples were Stephanodiscus astraea, S. astraea var. mintula, and F. crotonensis. The diatom flora in surface collections varied among several stations in the eastern end of the lake.

  8. Lake Mackay, Australia

    NASA Image and Video Library

    2017-09-27

    Lake Mackay is the largest of hundreds of ephemeral lakes scattered throughout Western Australia and the Northern Territory, and is the second largest lake in Australia. The darker areas indicate some form of desert vegetation or algae, moisture within the soils, and lowest elevations where water pools. The image was acquired on September 19, 2010 and covers an area of 27 x 41 km. With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C. More information about ASTER is available at asterweb.jpl.nasa.gov/. Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

  9. Lava Lakes on Io?

    NASA Astrophysics Data System (ADS)

    Lopes, R. M. C.; Kamp, L. W.; Smythe, W. D.; Howell, R.; Mouginis-Mark, P.; Kargel, J. S.; Radebaugh, J.; Turtle, E. P.; Perry, J.; Williams, D. A.; Carlson, R. W.; Doute, S.; Galileo NIMS Team

    2003-05-01

    At least 152 active volcanic centers have been identified on Jupiter's moon Io [Lopes et al., 2003, submitted to Icarus]. Eruptions at these centers include lava flows (``Promethean" type eruptions), explosive ``Pillanian" eruptions [Keszthelyi et al., 2001, JGR 106, 33,025-52] and volcanism confined within patera walls (``Lokian", Lopes et al., 2003). Understanding the Lokian eruption mechanism is particularly important because paterae are the most ubiquitous volcanic constructs on Io's surface [Radebaugh et al. 2001, JGR, 106, 33,005-33,020] and patera volcanism is the most common eruption type on Io. We use observations from Galileo's Near-Infrared Mapping Spectrometer (NIMS) and compare them with images from Galileo's Solid State Imaging system (SSI) to map the distribution of thermal emission at several Ionian paterae. This allows us to examine how thermal emission correlates with visible features, and to investigate how thermal emission varies with time. Galileo's close fly-bys of Io from 1999 to 2001 allowed NIMS to observe the volcanoes at relatively high spatial resolution (1-30 km pixel). At these scales, observations of the several paterae reveal that the greatest thermal emission occurs at the edges. This can be explained as the crust of a lava lake breaking up against the base of the patera (caldera) walls, similar to what has been observed at lava lakes on Earth. Comparison with terrestrial analogs shows that several Ionian active paterae, such as Loki, Tupan, and Emakong, have thermal properties consistent with relatively inactive lava lakes on Earth. We discuss these results and their implications for eruption styles and resurfacing on Io. This work was supported in part by NASA's Planetary Geology and Geophysics Program.

  10. Lake-floor sediment texture and composition of a hydrothermally-active, volcanic lake, Lake Rotomahana

    NASA Astrophysics Data System (ADS)

    Pittari, A.; Muir, S. L.; Hendy, C. H.

    2016-03-01

    Young volcanic lakes undergo a transition from rapid, post-eruptive accumulation of volcaniclastic sediment to slower pelagic settling under stable lake conditions, and may also be influenced by sublacustrine hydrothermal systems. Lake Rotomahana is a young (129 year-old), hydrothermally-active, volcanic lake formed after the 1886 Tarawera eruption, and provides a unique insight into the early evolution of volcanic lake systems. Lake-bottom sediment cores, 20-46 cm in length, were taken along a transect across the lake and characterised with respect to stratigraphy, facies characteristics (i.e., grain size, componentry) and pore water silica concentrations. The sediments generally comprise two widespread facies: (i) a lower facies of light grey to grey, very fine lacustrine silt derived from the unconsolidated pyroclastic deposits that mantled the catchment area immediately after the eruption, which were rapidly reworked and redeposited into the lake basin; and (ii) an upper facies of dark, fine-sandy diatomaceous silt, that settled from the pelagic zone of the physically stable lake. Adjacent to sublacustrine hydrothermal vents, the upper dark facies is absent, and the upper part of the light grey to grey silt is replaced by a third localised facies comprised of hydrothermally altered pale yellow to yellowish brown, laminated silt with surface iron-rich encrustations. Microspheres, which are thought to be composed of amorphous silica, although some may be halloysite, have precipitated from pore water onto sediment grains, and are associated with a decrease in pore water silicon concentration. Lake Rotomahana is an example of a recently-stabilised volcanic lake, with respect to sedimentation, that shows signs of early sediment silicification in the presence of hydrothermal activity.

  11. Seasonal bathythermal distribution of juvenile lake trout in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; Schneider, Clifford P.

    1987-01-01

    Bathythermal distributions of hatchery-reared lake trout (Salvelinus namaycush) of three genetic strains (Lake Superior; Clearwater Lake, Manitoba; and Seneca Lake, New York) were described from catches with bottom trawls in Lake Ontario during April-May, June, July-August, and October, 1978–1984. This work was part of a program to evaluate post-stocking performance of hatchery-reared fish and identify strains for continued use in rehabilitation of lake trout in Lake Ontario. All age groups of Lake Superior fish were in deeper water in April-May than in June each year; mean depth of capture was greatest at age II and became progressively shallower at ages III and IV. Mean depth of capture in April-May was positively correlated with severity of the preceding winter as judged by heating degree days and average wind speed. During July-August, the fish were concentrated between the epilimnion and 50 m, with no consistent trend in depth by age; however, 92% were captured at water temperatures of 12°C or lower. Mean temperatures of capture for Lake Superior fish during the four respective sampling periods were 3.9, 7.5, 6.9, and 9.5° C for fish of age II and 3.9, 8.4, 6.9, and 8.7° C for fish of age III. The age-II Clearwater Lake fish were consistently at shallower depths than age-II Lake Superior fish. Mean temperatures of capture were 4.2, 9.7, 9.6, and 10.7° C during the four respective sampling periods; during July-August, 91% were taken in water of 12° C or lower. The distribution of Seneca Lake fish was similar to that of the Lake Superior strain. Mean temperatures at which the three strains were captured were well below published preferred temperatures of yearlings in the laboratory. Annual variations in depth distributions during a given season were probably due to differing thermal regimes resulting from annual variations in the weather.

  12. Phosphorous Loading in Lake Champlain

    NASA Astrophysics Data System (ADS)

    Hoffman, H.; Halliday, B.; Lane, T.

    2016-12-01

    Phosphate movement from different sources into Lake Champlain is a problem. Excess phosphate generates algae growth causing eutrophication. This excessive growth known as algae blooms leads to poor water quality (State of Lake Report, 2015). Phosphate moves primarily by attachment to soil particles (Busman, Lamb, 09). Historically its movement has been limited to spring, summer and fall. Spring runoff is thought to contribute the most phosphate to Lake Champlain (Jensen, Tiessen, 11). With changes in global and local temperatures effecting weather patterns and the winter season, does phosphate continue to move into Lake Champlain during the winter months? Water samples from two tributaries to Lake Champlain were collected biweekly year around for the past three years. These samples were then tested for total suspended solids and phosphate levels. The results indicate that phosphate loading occurs throughout the year even during the winter months.

  13. L-Lake macroinvertebrate community

    SciTech Connect

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  14. Choking Lake Winnipeg

    NASA Astrophysics Data System (ADS)

    Byrne, J. M.; Little, L. J.; Dodgson, K. A.; MacDonald, R. J.; Graham, J.

    2009-12-01

    The problems of waterway eutrophication and coastal zone hypoxia are reaching epidemic proportions. Fresh water and coastal marine environments around the world are suffering unprecedented pollution loadings. We are developing an education program to address the dramatic need for public, community and K-12 education about the harsh impacts of elevated nutrient loads on fresh and marine water environments. The Lake Winnipeg watershed is adopted as the poster child of fresh water eutrophication in western North America. The watershed, one of the largest on the continent, is in rapid decline due to pollution, population pressures and water diversion. A concerted education program is needed to change personal and society actions that negatively impact the Winnipeg watershed; and the confluence of the watershed - Lake Winnipeg. But the education program goes beyond Lake Winnipeg. Negative impacts of nutrient loads are adversely affecting environments right to the oceans. Major dead zones that are expanding on our continental shelves due to nutrient overloading threaten to coalesce into extensive regions of marine life die-off. This presentation outlines the documentary education production process under development. We are building a series of Public Service Announcements (PSAs) for national television networks. The PSAs will direct educators, stakeholders and citizens to an associated website with educational video clips detailing the issues of eutrophication and hypoxia. The video clips or webisodes, present interviews with leading scientists. The discussions address the causes of the problems, and presents workable solutions to nutrient overloads from a variety of sources. The webisodes are accompanied by notes and advice to teachers on ways and means to use the webisodes in classrooms. The project is fully funed by a group of Canadian Community Foundations, with the understanding the work wil be available free to educators anywhere in the world. Our education

  15. Lake Shasta, California

    NASA Image and Video Library

    2015-06-17

    This image from NASA Terra spacecraft shows Shasta Lake in northern California, which has an area of 12,000 ha, making it the state largest reservoir. Impacts of the continuing drought in the western US is evident in the two ASTER images acquired 9 years apart. The images were acquired September 9, 2005 and September 2, 2014. They cover an area of 27.6 x 40.4 km, and are located at 40.6 degrees north, 122.4 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19492

  16. Great Lakes Harbors Study

    DTIC Science & Technology

    1966-11-01

    Locally.assigned Library of Congress number: HE396 S25 U55 Nj 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) 1. HARBORS 2... WATER TRANSPORTATION 3. ECONOMIC ANALYSIS 4. GREAT LJAKES - 20. ABSTRACT (Continue on ie.er.se side It necesaty nd identify by blocA number) Harbor...Scope 2 DESCRIPTION AND ECONOMIC DEVELOPMENT 3 Great Lakes-St. Lawrence Navigation System 2 4 Navigation Season 3 5 Water Levels 4 6 Tributary Area 6

  17. Lake Carnegie, Western Australia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Ephemeral Lake Carnegie, in Western Australia, fills with water only during periods of significant rainfall. In dry years, it is reduced to a muddy marsh. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on May 19, 1999. This is a false-color composite image made using shortwave infrared, infrared, and red wavelengths. The image has also been sharpened using the sensor's panchromatic band. Image provided by the USGS EROS Data Center Satellite Systems Branch. This image is part of the ongoing Landsat Earth as Art series.

  18. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Lake Erie Reenactment; Lake Erie, Put-in-Bay, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... vicinity of Put-In-Bay, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during Battle of Lake Erie Reenactment near Put-In-Bay. This temporary safety zone is necessary...

  19. Isotopic composition of Lake Agassiz-Ojibway water just prior to final drainage

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, C.; Helie, J.; McKay, J.; Lalonde, A.

    2006-12-01

    Controversies persist with respect to the impact of the final drainage of Lake Agassiz-Ojibway on the thermohaline circulation of the North Atlantic, some 8.4 ka ago. The lack of response of planktic foraminifer isotope records, off Hudson Strait (i.e., at the outlet of the drainage channel) constitutes one of the most puzzling elements in this debate. However, data on the isotopic composition of drainage waters are needed to estimate the response of the 18-O-salinity relationship in NW Atlantic surface waters. In the literature, a large array of isotopic compositions have been suggested, notably for modeling experiment purposes. Scattered information about the isotopic composition of Lake Agassiz water does exist. It includes isotopic measurements of pore waters of lacustrine sediments [1], analyses of oxygen isotopes in cellulose from algal or plant remains [2], and stable isotope compositions of concretions from varves [3]. Whereas, relatively low oxygen isotope values (apx. -25 per mil vs. VSMOW) are inferred for Lake Agassiz waters during cold pulses of the deglaciation, most data suggest much higher values during the final stages of Lake Agassiz-Ojiway, just prior to its drainage. Calcareous concretions from Lake Ojibway varves (not necessarily contemporaneous to the lacustrine stage) yielded oxygen isotope compositions of about -10 per mil (vs. VPDB), suggesting values as high as -14 per mil (vs. VSMOW) for pore waters (assuming a 0-4 degrees C temperature range). Similar high values (as high as -8 per mil vs. VSMOW [1]) were also estimated from pore water analyses of contemporaneous Lake Agassiz sediments. Here, we used a core raised from Eastern Hudson Bay, off Great Whale River, to further document isotopic compositions of the lake waters prior to their drainage into the North Atlantic. The 7.40 m long core has an apx. 1.3 m-thick lacustrine layer at its base, including the drainage sub- layer. It is overlain by Tyrrell Sea clays. Scarce valves of Candona

  20. The oscillating fringe and paleo-intensity of the East Asian monsoon reconstructed using closed-basin lake-area and dDwax

    NASA Astrophysics Data System (ADS)

    Goldsmith, Y.; Broecker, W. S.; Polissar, P. J.; Xu, H.; Lan, J.; Zhou, W.; An, Z.; deMenocal, P. B.

    2016-12-01

    The magnitude, rate and extent of East Asian Monsoon (EAM) rainfall changes during the late Pleistocene-Holocene is reconstructed using the first well-dated northeastern China lake-area record from a closed-lake basin, which enables reconstructing quantitative absolute paleo-rainfall amounts. In addition, compound specific hydrogen isotopes (dDwax) from lake-sediments are used to reconstruct the isotopic composition of rainwater (dP). Lake-levels were 60m higher than present during the early and middle Holocene. Requiring an absolute increase in mean annual rainfall to at least two times higher than today and a 400 km northward expansion. The EAM intensity and northern extent alternated abruptly between wet and dry periods on time scales of a few centuries. Both the onset ( 60 m rise at 11.5 ka BP) and termination ( 35 m drop at 5.5 ka BP) of the Holocene humid period occurred abruptly, within centuries. dDwax is negatively correlated with the lake area record (R2=0.77), showing for the first time, the co-evolution of dP and local rainfall amount. Lake level is also highly correlated with Both North and South Chinese stalagmite records. These results indicate that local distillation is a significant control on dP in East China, and that local rainfall amount is correlated with the intensity of the large EAM system. These results resolve a current debate regarding the use of dP as a proxy for rainfall amount and validate the "intensity-based" interpretations of the Chinese cave deposit records. The lake is located at the modern NW boundary of the EAM, therefore, lake level is governed by the northward extent of the EAM. The covariation of lake level and the intensity of the monsoon indicate that intensity and northward expansion of the EAM are linked and that during intense (weak) EAM periods the EAM northwestern boundary shifts northward (southward).

  1. Mineralogy, geochemistry and genesis of the modern sediments of Seyfe Lake, Kırşehir, central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Önalgil, Nergis; Kadir, Selahattin; Külah, Tacit; Eren, Muhsin; Gürel, Ali

    2015-02-01

    Seyfe Lake (Kırşehir, Turkey) is located within a depression zone extending along a NW-SE-trending fault in central Anatolia. Evaporite and carbonate sediments occur at the bottom of the lake which is fed by high-sulfate spring and well waters circulating N-S through salt domes. The recent sediments of Seyfe Lake are deposited in delta, backshore, beach, mud-flat and shallow lake environments. In the mud-flat environment, calcite, gypsum, halite, and thenardite are associated with fine-grained detrital sediments. Sediments from the margin to the lake center are distributed as calcite, gypsum and halite ± thenardite, yielding an annular distribution pattern. An increase in Na2O, SO3, and S, and a decrease in CaO toward the lake center are due to sediment distribution. On the other hand, a positive correlation of SiO2 with MgO, K2O, Na2O, Al2O3, and Fe2O3 + TiO2 is attributed to the presence of smectite, illite and feldspar. In addition, a positive correlation of Sr and Ba with CaO is related to the amount of gypsum in the sediments. Strontium is associated with in situ gypsum crystals; it increases in the intermediate and central zones of the lake as a result of a relative increase in salinity toward the lake center. The association of Sr with gypsum in the sediments suggests that Ca and Sr were derived from Sr-bearing evaporites and their carbonate host rocks, which were the likely aquifers for the brine. The S- and O-isotopic compositions of sulfate crystals range from +19.1‰ to +21.7‰ and from +16.9‰ to +20.9‰ SMOW, respectively, suggesting precipitation in a closed lake system. A relative increase of oxygen and sulfur isotope ratios toward the lake center suggests dissolution of gypsum in the host rock, with contributions from circulating groundwater and sulfate reduction (possibly by bacterial reduction). 87Sr/86Sr isotope ratios range from 0.707286 to 0.707879, suggesting a non-marine Oligo-Pliocene evaporitic host rock source for precipitation in

  2. Will Lake Michigan lake trout meet the Great Lakes Strategy 2002 PCB reduction goal?

    PubMed

    Stow, Craig A; Lamon, E Conrad; Qian, Song S; Schrank, Candy S

    2004-01-15

    The Great Lakes Strategy 2002 establishes the long-term goal that all Great Lakes fish should be safe to eat without restriction. As an indicator of progress toward that goal, the Strategy specifies that lake trout PCBs will decline 25% from 2000 to 2007. We estimated the plausibility of achieving this near-term goal by examining a time-series of Lake Michigan lake trout PCB concentrations from 1972 to 2000. We used two different Bayesian approaches, Bayesian model averaging (BMA) and dynamic linear models (DLM), to model the trajectory of these historical data and forecast concentrations through 2007. Both approaches indicate that the probability of a 25% reduction from 2000 to 2007 is negligible. The most likely lake trout PCB declines predicted by the BMA and DLM over this time period are 6.8% and 8.9%, respectively. Our results suggest that declines in lake trout PCBs will be in the range of 5-10% assuming conditions similar to recent years. This rate of decline will be difficult to discern without adequate data collection. If sufficient data are not gathered to document further declines, then the relaxation of lake trout consumption advisories is indeed a long-term prospect.

  3. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Special requirements, Lake Campbell and... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports. Each person operating an aircraft to or from Lake Campbell or Sixmile Lake Airport shall conform to the flow...

  4. PLAT X41601 EAST (SALT LAKE CITY CEMETERY LOCATER), SALT LAKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PLAT X-4-160-1 EAST (SALT LAKE CITY CEMETERY LOCATER), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT CEMETERY BETWEEN OLIVE STREET (1020 EAST) AND 1000 EAST STREET, REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 12049, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  5. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Sixmile Lake Airports. 93.69 Section 93.69 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports. Each person operating an aircraft to or from Lake Campbell or Sixmile Lake Airport shall conform to the...

  6. 77 FR 39638 - Safety Zone; Barbara Harder Wedding Fireworks, Lake Erie, Lake View, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... No. USCG-2012-0568] RIN 1625-AA00 Safety Zone; Barbara Harder Wedding Fireworks, Lake Erie, Lake View... temporary safety zone on Lake Erie, Lake View, NY. This safety zone is intended to restrict vessels from a portion of Lake Erie during the Barbara Harder Wedding Fireworks. This temporary safety zone is necessary...

  7. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ... temporary safety zone upon the navigable waters of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix. This temporary safety zone is necessary to provide for the safety...

  8. 75 FR 13232 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... Pipe from Lake Mead throughout 2010. This safety zone is necessary to ensure non-authorized personnel...

  9. 78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ... temporary safety zone within the navigable waters of Lake Havasu and the London Bridge Channel for the Lake... Triathlon will consist of 600 participants. The waterside swim course consists of 1500 meters in Lake Havasu...

  10. 76 FR 2579 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... blasting operations for the placement of a water intake pipe in Lake Mead during the first 6 months of 2011...

  11. Congener specific PCB distribution in lake trout/siscowets and walleye from the Great Lakes

    SciTech Connect

    Zabik, M.J.; Zabik, M.E.; Booren, A.M.; Daubenmire, S.; Pascall, M.; Dickmann, G.; Khedr, G.

    1995-12-31

    Lean lake trout (Salvelinus namaycush) from Lakes Huron, Michigan and Ontario and siscowets (fat lake trout) from Lake Superior as well as walleye (Stizotedium vitreum vitreum) from Lakes Erie, Huron and Michigan were analyzed for 53 PCB congeners commonly found in Aroclor 1254. The average PCB congener pattern is presented for a minimum of 12 fish from each species from each lake and the distribution of PCB congeners among species and lakes is compared. Greater differences were found for the lake source of the lake trout than for the walleye. Lake trout from Lake Ontario had high levels of congener 198. Lake trout from Lakes Huron and Superior also tended to have higher levels of higher chlorinated congeners while lake trout from Lake Michigan had the highest levels of the lower chlorinated congeners. Fewer lake effect differences were found for distribution of PCB congeners for the walleye. Walleye from Lake Huron had a greater percentage of the total PCB congeners with lower chlorination than did lake trout but the pattern of percent of total for lake trout and walleye from Lake Michigan was quite similar.

  12. NASA Satellite Scares Up An Eerie Image of Haunted Lakes and Ghost Ships

    NASA Image and Video Library

    2011-10-29

    NASA Terra satellite presents this false color view of portions of Wisconsin and Michigan, including Devil Lake, Druid Lake, Ghost Lake, Spider Lake, and Witches Lake in Wisconsin; and Bat Lake, Corpse Pond and Witch Lake in Michigan.

  13. EPA Research Strengthens Great Lakes Restoration Initiative

    EPA Science Inventory

    As the largest group of freshwater lakes on Earth, the Great Lakes (Lakes Erie, Huron, Michigan, Ontario and Superior) are a source of economic prosperity, recreation and raw materials. Human activity, however, has resulted in pollution and other stressors. The Great Lakes curren...

  14. TOXAPHENE IN THE GREAT LAKES. (R825246)

    EPA Science Inventory

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  15. EPA Research Strengthens Great Lakes Restoration Initiative

    EPA Science Inventory

    As the largest group of freshwater lakes on Earth, the Great Lakes (Lakes Erie, Huron, Michigan, Ontario and Superior) are a source of economic prosperity, recreation and raw materials. Human activity, however, has resulted in pollution and other stressors. The Great Lakes curren...

  16. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...; then (3) Along the shoreline until the point where the Lake Carlos shoreline parallels an unlabeled... point at BM 1411; then (7) North from BM 1411 in a straight line to the south shoreline of Lake Miltona; then (8) Generally west along the south shoreline of Lake Miltona onto the Lake Miltona West, Minn....

  17. TOXAPHENE IN THE GREAT LAKES. (R825246)

    EPA Science Inventory

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  18. 27 CFR 9.127 - Cayuga Lake.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area is...

  19. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Finger Lakes. 9.34 Section... Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural area...

  20. 33 CFR 125.08 - Great Lakes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Great Lakes. 125.08 Section 125... VESSELS § 125.08 Great Lakes. The term Great Lakes as used in the regulations in this subchapter shall include the Great Lakes and their connecting and tributary waters. ...