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Sample records for field michoacan mexico

  1. Pilot fruit drier for Los Azufres geothermal field, Michoacan, Mexico

    SciTech Connect

    Lund, J.W.

    1993-02-01

    Comision Federal de Electricidad (CFE) has a Division in charge of the exploration of a geothermal reservoir located in Los Azufres, State of Michoacan. At present, CFE is only using the steam of the wells and rejecting the hot water that comes off associated with the steam. Based on a trip to the Los Azufres geothermal field in December of 1992, a design for a pilot geothermal fruit drier was undertaken for CFE. The details of the geothermal field and the local fruit production are detailed.

  2. Pilot fruit drier for Los Azufres geothermal field, Michoacan, Mexico

    SciTech Connect

    Lund, J.W.

    1993-02-01

    Comision Federal de Electricidad (CFE) has a Division in charge of the exploration of a geothermal reservoir located in Los Azufres, State of Michoacan. At present, CFE is only using the steam of the wells and rejecting the hot water that comes off associated with the steam. Based on a trip to the Los Azufres geothermal field in December of 1992, a design for a pilot geothermal fruit drier was undertaken for CFE. The details of the geothermal field and the local fruit production are detailed.

  3. Differentiation of cinder cone magmas from the Michoacan-Guanajuato Volcanic Field, central Mexico

    SciTech Connect

    Hasenaka, T.

    1985-01-01

    The Michoacan-Guanajuato Volcanic Field (area:40,000 km/sup 2/) contains various small volcanic centers of 3 Ma to Recent age, including 900 cinder and lava cones, and contrast to other portions of the Mexican Volcanic Belt (MVB) with large composite volcanoes. Among 224 scoria and lava samples studied for chemistry and mineralogy, 165 samples are calc-alkaline (basalt, andesite, and dacite), 21 are alkaline (mainly basalt), and 38 are transitional between the two (mainly basalt). The majority of rocks are 01 basalt and 01 andesite with pyroxene and hornblende andesites being subordinate. Their MgO content is relatively high compared with lavas from composite volcanoes in the MVB, and indicate an earlier stage of differentiation. Four samples have Mg-number >70 and Ni content >235 ppm, a criteria of magmas equilibrated with mantle olivine. They include all the rock groups but phenocryst assemblage is always 01+Cpx+Pl. Other samples are plotted between this and 1-atmosphere Ol-Cpx-Pl cotectic. Ol-liquid, two pyroxenes, and magnetite-ilmenite temperatures decrease from 1200/sup 0/C to 900/sup 0/C with increasing FeO*/MgO ratio which also corresponds to the changing mineral assemblages. Calculated oxygen fugacities are on or slightly above Ni-NiO buffer line. Calc-alkaline and alkaline basalts are not related; both are parental. Less differentiated character of cinder cone magmas may result from their transportation under local extensional stress and absence of long-lived shallow magma reservoirs is common in composite volcanoes.

  4. Rapid assessment of endemic bird areas in Michoacan, Mexico

    Treesearch

    Gilberto Chavez-Leon; Deborah M. Finch

    1999-01-01

    Non-sustainable land use practices in the state of Michoacan, Mexico, have perturbed endemic bird h~bitats for several decades. Endemic birds have a restricted geographic and ecological distribution. This feature makes them suitable to be used as indicators of biological diversity and environmental perturbation. Forty-one Mexican endemic species have been recorded in...

  5. 7 CFR 319.56-30 - Hass avocados from Michoacan, Mexico.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Hass avocados from Michoacan, Mexico. 319.56-30... § 319.56-30 Hass avocados from Michoacan, Mexico. Fresh Hass variety avocados (Persea americana) may be... of this subpart, and only under the following conditions: (a) Shipping restrictions. (1) The...

  6. 7 CFR 319.56-30 - Hass avocados from Michoacan, Mexico.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Hass avocados from Michoacan, Mexico. 319.56-30... § 319.56-30 Hass avocados from Michoacan, Mexico. Fresh Hass variety avocados (Persea americana) may be... of this subpart, and only under the following conditions: (a) Shipping restrictions. (1) The...

  7. 7 CFR 319.56-30 - Hass avocados from Michoacan, Mexico.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Hass avocados from Michoacan, Mexico. 319.56-30... § 319.56-30 Hass avocados from Michoacan, Mexico. Fresh Hass variety avocados (Persea americana) may be... of this subpart, and only under the following conditions: (a) Shipping restrictions. (1) The...

  8. 7 CFR 319.56-30 - Hass avocados from Michoacan, Mexico.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Hass avocados from Michoacan, Mexico. 319.56-30... § 319.56-30 Hass avocados from Michoacan, Mexico. Fresh Hass variety avocados (Persea americana) may be... of this subpart, and only under the following conditions: (a) Shipping restrictions. (1) The...

  9. The ignimbritic sequences of the Michoacan and Jalisco blocks, western Mexico

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Gogichaishvili, A.; Alva-Valdivia, L.

    2011-12-01

    The Southern-central Mexico is related to the relative motions between the Pacific and Northamerica plates involving subduction, terranes accretion, and retreat of the trench; as consequence this region has a complex geologic evolution forming the so called tectono-stratigraphic terranes. The Guerrero Terrain was define by Campa and Coney (1983) as formed by island-arcs sequences accreted in Tertiary-Late Cretaceous times. The Michoacan and Jalisco blocks belong to the Guerrero terrain. The Cretaceous-Tertiary rocks of the Jalisco block are intrusive, volcano-sedimentary, metamorphic and volcanic rocks. The youngest succession is a widespread ignimbrite sequence. As in the Jalisco block, at the Michoacan block the Cretaceous sedimentary and volcano-sedimentary rocks are mantled by an ignimbrite sequence. In the Jalisco block 11 radiometric ages have been reported for ignimbrite sequence but in the Michoacan block (between the Infiernillo dam and the Colima graben) none isotopic age has been published for the ignimbrite succession but the Servicio Geológico Mexicano gives an Eocene-Miocene age. We report our preliminary structural and geochronologic work in the Michoacan and Jalisco blocks. Radiometric results do not support an Eocene-Miocene age. We sampled a rhyolitic ignimbrite unit (called ignimbrita Laureles) south of the Tepalcatepec city for 40Ar/39Ar radiometric studies which gives an age of 70 Ma. At the same time we sampled a rhyolitic ignimbrite unit (called ignimbrita Union) isotopic age gives 66 Ma. During our field work we did not find significant deformation in the ignimbrite cover but the underlying sedimentary and volcano-sedimentary sequences are highly deformed. Campa, U. M.F., and P. Coney, 1983 Tectonostratigraphic terranes and mineral resource distribution in Mexico, Canadian Journal of Earth Sciences, v.20, p.1040-1051.

  10. Paleomagnetic study of Ar-Ar dated lava flows from Tancitaro Volcano and Tacambaro area, The Michoacan Guanajuato Volcanic Field (Western Mexico)

    NASA Astrophysics Data System (ADS)

    Maciel, R.; Gogichaishvili, A.; Garduño, V. H.; Ruiz Martinez, V. C.; Aguilar Reyes, B.; Morales Contreras, J.

    2009-05-01

    We sampled eleven fresh, apparently not altered outcrops out of 26 sites reported recently while 27 independent cooling units were collected at Tacambaro area belonging to the Michoacan Guanajuato Volcanic Field. All studied sites were dated by means of state-of-the-art 40Ar-39Ar geochronological method and span from 1.23 ± 0.2 ma to present. Low-field continuous susceptibility measurements performed in air show the presence of a single ferrimagnetic phase with Curie point compatible with Ti-poor titanomagnetite. The cooling and heating curves are reasonably reversible. Polished section observations under microscope also confirmed the presence of a near-magnetite phase associated with exsolved ilmenite of trellis or sometimes sandwich texture. In most samples a single and stable component of magnetization was observed upon thermal, alternating field or combined treatments. A secondary component, probably due to the lightning effects was present but was easily removed at very first steps of demagnetization. The mean direction is in agreement with the expected paleodirections for the late Pliocene, as derived from reference poles for the North American plate. Combining the available geochronologic data with the magnetic polarity, better constraints of the age of emplacement are achieved.

  11. Integral description of the geological heritage of Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    jose teodoro, S. G.; Gonzalez, C.; Estrada, F.; Moncayo, R.; Cruz, G.

    2013-12-01

    Geological heritage studies are among the most recent research areas incorporated into the geological sciences. These represent a new understanding of man's relationship with earth. Particularly, the Geosites Global Project was structured as an international initiative aimed to establish the geological heritage. Similarly, UNESCO in 1996 launched the Geoparks Program, in order to register in confined areas peculiar aspects for scientific research, uniqueness and beauty that could perpetuate the geological history and the processes that formed them. This initiative includes the global geological record, which selects the most representative and illustrative places. The analysis of the geological heritage can be approached in different ways, either through cataloging, valuation, preservation or disclosure, all of these activities, together, provide an integrated management model. In a first step, we addressed the first two approaches for the north-central portion of the state of Michoacan Mexico. The Paricutin and Jorullo volcanoes, the overlapping tectonic sequences Tzitzio-Huetamo, and the Michoacán-Guanajuato Volcanic Belt, are just some examples. We pretend to focus the inventory and valuation activities, to formulate protection schemes and management strategies as cultural resources.

  12. Patterns of forest use and endemism in resident bird communities of north-central Michoacan, Mexico

    Treesearch

    Santiago Garcia; Deborah M. Finch; Gilberto Chavez. Leon

    1998-01-01

    We compared breeding avian communities among 11 habitat types in north-central Michoacan, Mexico, to determine patterns of forest use by endemic and nonendemic resident species. Point counts of birds and vegetation measurements were conducted at 124 sampling localities from May through July, in 1994 and 1995. Six native forest types sampled were pine, pine-oak, oak-...

  13. Michoacan: The Region and Its People. A Unit of Study for Grades 2 & 3. Fulbright-Hays Summer Seminars Abroad, 1999 (Mexico).

    ERIC Educational Resources Information Center

    Barberena, Gretchen

    This curriculum unit, intended to be used with students in grades 2 and 3, focuses on the Mexican state of Michoacan. Lesson 1 first gives students an overview of Mexico. Lesson 2 provides an introduction to a Michoacan archeological dig, while lesson 3 focuses on the geography of Michoacan. Lesson 4 discusses Purepecha weaving. Lesson 5 presents…

  14. Receiver Function Imaging of Crustal and Lithospheric Structure Beneath the Jalisco Block and Western Michoacan, Mexico.

    NASA Astrophysics Data System (ADS)

    Reyes Alfaro, G.; Cruz-Atienza, V. M.; Perez-Campos, X.; Reyes Dávila, G. A.

    2014-12-01

    We used a receiver function technique for imaging western Mexico, a unique area with several active seismic and volcanic zones like the triple junction of Rivera, Cocos and North American plates and the Colima volcano complex (CVC), the most active in Mexico. Clear images of the distribution of the crust and the lithosphere-asthenosphere boundary are obtained using P-to-S receiver functions (RF) from around ~80 broadband stations recorded by the Mapping the Rivera Subduction Zone (MARS), the Colima Volcano Deep Seismic Experiment (CODEX) and a local network (RESCO) that allowed us to considerably increase the teleseismic database used in the project. For imaging, we constructed several 2-D profiles of depth transformed RFs to delineate the seismic discontinuities of the region. Low seismic velocities associated with the Michoacan-Guanajuato and the Mascota-Ayutla-Tapalpa volcanic fields are also observed. Most impressive, a large and well delineated magma body 100 km underneath CVC is recognized along a surely related depression of the moho discontinuity just above it. We bring more tools for a better understanding of the deep processes that ultimately control eruptive behavior in the region.

  15. Taxonomic and floristic novelties for Echeveria (Crassulaceae) in Central Michoacan, Mexico

    PubMed Central

    García-Ruiz, Ignacio; Valentín-Martínez, Dagoberto; Carrillo-Reyes, Pablo; Costea, Mihai

    2016-01-01

    Abstract A new species, Echeveria coruana, is described and illustrated from the malpaís near San Andrés Corú, Michoacan, Mexico. The species belongs to series Gibbiflorae and the new taxon was compared with Echeveria purhepecha and Echeveria patriotica, with whom it shares the closest morphological affinities. Additionally, Echeveria yalmanantlaensis an endangered species from Sierra of Manantlán Biosphere Reserve, State of Colima, was also discovered near San Andrés Corú and is reported for the first time from the State of Michoacan. The conservation status of both species was (re)evaluated according to the criteria of the International Union for Conservation of Nature. PMID:28127240

  16. Taxonomic and floristic novelties for Echeveria (Crassulaceae) in Central Michoacan, Mexico.

    PubMed

    García-Ruiz, Ignacio; Valentín-Martínez, Dagoberto; Carrillo-Reyes, Pablo; Costea, Mihai

    2016-01-01

    A new species, Echeveria coruana, is described and illustrated from the malpaís near San Andrés Corú, Michoacan, Mexico. The species belongs to series Gibbiflorae and the new taxon was compared with Echeveria purhepecha and Echeveria patriotica, with whom it shares the closest morphological affinities. Additionally, Echeveria yalmanantlaensis an endangered species from Sierra of Manantlán Biosphere Reserve, State of Colima, was also discovered near San Andrés Corú and is reported for the first time from the State of Michoacan. The conservation status of both species was (re)evaluated according to the criteria of the International Union for Conservation of Nature.

  17. Parasite search in strawberries from Irapuato, Guanajuato and Zamora, Michoacan (Mexico).

    PubMed

    Spíndola Félix, N; Rojas Wastavino, G; de Haro Arteaga, I; Cabrera Bravo, M; Salazar Schettino, P M

    1996-01-01

    A seasonal research was carried out in Irapuato, Guanajuato and Zamora, Michoacan, Mexico, the location of the most important producers of strawberries, in order to assess fecal contamination through the finding of protozoan cysts and helminth eggs, specifically of Taenia sp eggs. Three techniques were used: direct observation, flotation and sedimentation. Low numbers of protozoan cysts and only one Ascaris egg were found. What is most interesting is that no Taenia eggs were identified. Results indicate that although strawberries are contaminated with human feces, contamination is minimal.

  18. Altitudinal genetic variation among Pinus oocarpa populations in Michoacan, Mexico: implications for seed zoning, conservation, tree breeding and global warming

    Treesearch

    Cuauhtemoc Saenz-Romero; R. Ricardo Guzman-Reyna; Gerald E. Rehfeldt

    2006-01-01

    Pinus oocarpa has a large natural distribution in the sub-tropical forests of Mexico. Populations, however, are rapidly disappearing particularly in the Michoacan State as native forests are converted to avocado (Persea sp.) orchards.We investigated the patterning of genetic variation among P. oocarpa populations...

  19. Strong ground motion from the michoacan, Mexico, earthquake.

    PubMed

    Anderson, J G; Bodin, P; Brune, J N; Prince, J; Singh, S K; Quaas, R; Onate, M

    1986-09-05

    The network of strong motion accelerographs in Mexico includes instruments that were installed, under an international cooperative research program, in sites selected for the high potenial of a large earthquake. The 19 September 1985 earthquake (magnitude 8.1) occurred in a seismic gap where an earthquake was expected. As a result, there is an excellent descripton of the ground motions that caused the disaster.

  20. June 2006 seismic swarm and dike injection event beneath the Michoacan-Guanajuato volcanic field

    NASA Astrophysics Data System (ADS)

    Cox, T. F.; Gardine, M.; West, M.

    2008-12-01

    A seismic swarm of approximately 700 events, magnitude 2.5-3.5, occurred in June of 2006 approximately 15 km from the summit of the cinder cone Paricutin, in the Michoacan-Guanajuato Volcanic Field in central Mexico. The swarm was detected and located as part of an effort to develop a catalog of regional seismicity using stations fortuitously in place as part of two concurrent IRIS/PASSCAL supported projects- the Mapping of the Rivera Subduction Zone (MARS) project run by the University of Texas at Austin and New Mexico State University, and the Colima Volcano Deep Seismic Experiment (CODEX), run by the University of Alaska Fairbanks. Over a two-week period in June 2006, relocated hypocenters clearly show a shallowing trend with time, indicative of a possible dike injection event. The rate of injection appears to be 346 m/day. Following the injection, there is a period of earthquakes, which all occurred at approximately 5 km in depth, but which migrated southwards. The waveforms of all of these events show similarities within three major groupings: from May 28 to June 1, June 2 to June 9 (which marks the end of the ascent), and from June 9 to July 2.

  1. The 27 May 1937 catastrophic flow failure of gold tailings at Tlalpujahua, Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Macias, J. L.; Corona-Chavez, P.; Sanchez-Nunez, J. M.; Martinez-Medina, M.; Garduno-Monroy, V. H.; Capra, L.; Garcia-Tenorio, F.; Cisneros-Maximo, G.

    2015-05-01

    On 27 May 1937, after one week of sustained heavy rainfall, a voluminous flood caused the death of at least 300 people and the destruction of the historic El Carmen church and several neighborhoods in the mining region of Tlalpujahua, Michoacan, central Mexico. This destructive flood was triggered by the breaching of the impoundment of the Los Cedros tailings and the sudden release of circa 16 Mt of water-saturated waste materials. The muddy silty flood, moving at estimated speeds of 20-25 m s-1, was channelized along the Dos Estrellas and Tlalpujahua drainages and devastated everything along its flow path. After advancing 2.5 km downstream, the flood slammed into El Carmen church and surrounding houses at estimated speeds of ~ 7 m s-1, destroying many construction walls and covering the church floor with ~ 2 m of mud and debris. Revision of eyewitness accounts and newspaper articles, together with analysis of archived photographic materials, indicated that the flood consisted of three muddy pulses. Stratigraphic relations and granulometric data for selected proximal and distal samples show that the flood behaved as a hyperconcentrated flow along most of its trajectory. A total volume of the Lamas flood deposit was estimated as 1.5 x 106 m3. The physically based bidimensional (2-D) hydraulic model FLO-2D was implemented to reproduce the breached flow (0.5 sediment concentration) with a maximum flow discharge of 8000 m3 s-1 for a total outflow volume (sediment + water) of 2.5 x 106 m3, similar to the calculations obtained using field measurements. Even though premonitory signs of possible impoundment failure were reported days before the flood, and people living downstream were alerted, authorities ordered no evacuations or other mitigative actions. The catastrophic flood at Tlalpujahua provides a well-documented, though tragic, example of impoundment breaching of a tailings dam caused by the combined effects of intense rainfall, dam weakness, and inadequate

  2. Sintacs Aquifer Vulnerability in the Definition of the Natural Protected Area Los Chorros Del Varal, Los Reyes, Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Silva, J.; Ramiro, R.; Estrada, F.; Ochoa, S.

    2006-12-01

    In Michoacan State, Mexico, the use of aquifer vulnerability assessment is been incorporated in the regional policies of aquifer protection. A hydrogeological evaluation and aquifer vulnerability assessment using the SINTACS method was done in the natural protected area, NPA, Los Chorros del Varal in Michoacan State, Central Mexico. This place is a discharge area. An spectacular spring is feeding a stream. The predominant rocks are volcanic. By means of the SINTACS method a contamination risk zoning was obtained. The research permitted the expansion of the protection area of Los Chorros del Varal: a surrounding area to avoid anthropogenic impacts. This NPA is the preferential recharge area of the regional aquifer. This aquifer is the main water supply source for more than 200,000 inhabitants. A high to medium vulnerability was calculated. These vulnerable parts must be protected impeding risky projects such as dumps or industries producing wastewaters. Low values were obtained in clayey environments and also in volcanic rocks with scarce fracturing.

  3. Seroprevalence of and risk factors for brucellosis of goats in herds of Michoacan, Mexico.

    PubMed

    Solorio-Rivera, J L; Segura-Correa, J C; Sánchez-Gil, L G

    2007-12-14

    Our objectives were to estimate the seroprevalence of Brucella melitensis, and to identify some risk factors associated with goat seropositivity in Michoacan, Mexico. Blood samples were collected from 5114 animals from 79 herds. Sera were tested for antibodies against B. melitensis using the Rose Bengal plate test and the complement-fixation test. Information regarding the herds and each animal sampled were recorded through a personal interview at the farm. We used random-effects multivariable logistic regression to analyze our data. Fifty-six herds of the 79 tested had at least one seropositive animal. The animal-level true seroprevalence was 9.8% (CI=8.8, 10.7). Animals in large herds (>34 animals), in herds with high stock density (>3.5 animals/m(2)) or animals >24 months old had higher odds of seropositivity (2.0, 1.7 and 1.8, respectively) than those in small herds, in herds with low stock density or animals < or =24 months old.

  4. Geomorpho-edaphic mapping of Atécuaro catchment (Michoacan, Mexico) and indigenous soil classification

    NASA Astrophysics Data System (ADS)

    Alanís González, N.; Alcalá de Jesús, M.; Arellano Reyes, A.; Jordán, A.; Zavala, L. M.

    2012-04-01

    The needs of management and conservation of land involve the study of natural resources and their internal relationships. Over time, these resources, including soil, have been used in an uncontrolled manner, resulting in species extinction and environmental degradation processes. The main reason for this in developing areas is the lack of soil and geomorphological information for an adequate land use planning. Often, ethnopedological knowledge and the inclusion of indigenous communities as beneficiaries of the agricultural technology are indispensable premises to make a better use of soil. A geomorphology and soil survey was conducted in the Atécuaro catchment (4591 ha), in the municipality of Morelia (Michoacan, Mexico). The Atécuaro catchment is located in the Mil Cumbres area, and is characterized by an irregular relief and a diversity of landforms and substrates (andesite, rhyolite, basalt, tuff and Quaternary sediments). The main land uses are oak and pine forest, shrubland, grassland and dryland farming. Results of the soil survey and the analysis of geoforms were studied and incorporated in a geographycal information system. Preliminary geoform and soil units maps were overlapped in order to get a map of geomorpho-edaphic units. Up to 30 different geomorpho-edaphic units were classified. Finally, map units were correlated with local indigenous soil classification.

  5. Climate-Floods relationship in the mountainous volcanic region of Morelia, Michoacan, Mexico.

    NASA Astrophysics Data System (ADS)

    Vinson, D.; Gratiot, N.; Saenz-Romero, C.; Prat, C.; Esteves, M.

    2009-04-01

    The present study provides an analysis of the water flows in the mountainous volcanic watershed of Cointzio, Michoacan (Mexico). Daily precipitations and river flows data, gathered over the period 1940-2007, were analysed to estimate the dynamic of superficial waters and its change over years. Precipitation data pointed out the intensity of rains in this tropical region with 5% of the yearly precipitation occurring during a single day. It also reveals an unexpected feature with some extreme events occurring during the dry season. This obviously as some major consequences for the floods and sediment transport within the watershed. For the studied period, the precipitation (mean annual and extreme values) did not reveal any major change while the water flows increased significantly. This specific behaviour is examined in terms of land use change through the evolution of an aridity index over years and literature data. Predictions from a global climate change model for the decades centred in the years 2030, 2060 and 2090 indicate (in comparison to a normalized period of years 1961 to 1990) an increment in mean annual temperature of 1.6, 2.5 and 4.4 °C and a decrease in precipitation of 15.4, 19.1 and 27.7 %, respectively. The consequent increment of aridity leads to expect a reduction of the vegetation coverage and an increment of the runoff with erosive effects.

  6. 52,000 yr. of Environmental History in Zacapu Basin, Michoacan, Mexico: the Magnetic Record

    NASA Astrophysics Data System (ADS)

    Ortega, B.; Caballero, C.; Schaaf, P.; Israde, I.

    2001-12-01

    Many lake sediments in Central Mexico have been found to record not only the natural climatic variations but also have experienced alterations due to volcanism, active tectonics and human activity. With the aim to obtain a record of the climatic and environmental changes spanning the Last Glacial Maximum, a 10.90 m long core was drilled in Zacapu basin, Michoacan, Mexico (19º 50' N; 101º 44' W). Sedimets were characterized by the mesurement of total organic carbon (TOC), Xlf, ARM, MR, MS, BCR, BC, S300 ratio, and low temperature (10-300 K) remanence and frequency dependence susceptibility measurements. X, ARM/MR and S300 ratios, and TOC were chosen to represent magnetic concentration, grain size, and hardness, and organic productivity, in order to obtain a reliable characterization of the sediments that allow an environmental interpretation. Volcanic activity is clearly one of the most affecting events in the environment. Last glacial sediments record the existence of a shallow lake. Low lake levels are characterized by fine, relatively unaltered Ti-magnetite and probably of biogenic magnetite, and episodes of drying are characterized by coarse magnetic grains, and a high proportion of goethite. Late glacial sediments have high SP content. A deeper phase between 43ka and 39ka yr BP is characterized by coarser grains and higher quantities of a magnetic hard phase, presumably goethite. At 35ka yr BP low TOC and Xf, finer and softer minerals reflect the onset of relatively dry conditions. Drier than previous conditions persisted throughout the Late Glacial and mid Holocene, and were particularly dry between ca. 14ka and 4.8ka yr BP. There is also a marked decrease in the SP fraction, interpreted as result of the decline of soil forming processes. Late Holocene is characterized by increased TOC, likely to eutrophication, which reflects the human impact in the basin.

  7. Ungoverned Spaces in Mexico: Autodefensas, Failed States, and the War on Drugs in Michoacan

    DTIC Science & Technology

    2014-12-01

    recognized leaders of those 72 Presidencia de la Republica , “5 Ejes para Lograr una Democracia de...Police],” Parametria, accessed August 25, 2014, http://parametria.com.mx/carta_parametrica.php?cp=4514 91 Gobierno de la Republica , “Plan Nacional...es.insightcrime.org/noticias-del-dia/nuevo-cartel-michoacan-refuerza- temores-criminalizacion-autodefensas Presidencia de la Republica . “5 Ejes para Lograr una

  8. Laramide thrusting and Tertiary deformation Tierra Caliente, Michoacan and Guerrero States, southwestern Mexico

    SciTech Connect

    Johnson, C.A.; Harrison, C.G.A. ); Lang, H. ); Barros, J.A.; Cabral-Cano, E.

    1990-05-01

    Field investigations and detailed interpretations of Landsat Thematic Mapper images are in progress to improve understanding of regional structure and tectonics of the southernmost extension of the North American cordillera. Two areas have been selected within the Ciudad Altamirano 1:250,000 topographical sheet for geologic mapping and structural interpretation at 1:50,000 scale. The authors results to date require modification of previous ideas concerning the style and timing of deformations, the role and timing of terrane accretion in the overall tectonic history of the region, and the importance of southern Mexico to investigations of the tectonic evolution of the plates in the region. The relative sequence of deformation in the area correlates well with variations in relative motion between North America and plates in the Pacific. Post-Campanian thrusts and generally eastward-verging folds deformed the Mesozoic sequence during the (Laramide equivalent) Hidalgoan orogeny, associated with high-velocity east-west convergence with the Farallon plate that began about 70 Ma. The resulting unconformity was covered by the Tertiary Balsas Formation, a thick sequence of mostly continental clastics. The Tertiary stratigraphy is regionally and sometimes locally variable, but it can be divided into two members. The lower member is relatively volcanic poor and more deformed, and it lies below a regionally significant mid-Tertiary unconformity, which may mark a change to northeast-directed convergence with the Farallon plate sometime prior to 40 Ma. Continued mid-Tertiary deformation in southern Mexico may be related to eastward movement of the Chortis block and the resulting truncation of the Pacific margin of Mexico. The authors also suggest a tentative correlation between the volcaniclastic member of the Lower Cretaceous San Lucas Formation and the protolith of the Roca Verde metamorphics to the east.

  9. High blood lead levels in ceramic folk art workers in Michoacan, Mexico.

    PubMed

    Fernandez, G O; Martinez, R R; Fortoul, T I; Palazuelos, E

    1997-01-01

    Ceramic folk art workers are at risk for developing lead intoxication. These workers live in small settlements, which often lack sanitation services, and these individuals work with ceramics in their homes. The study population comprised individuals of all ages from three rural communities in central Michoacan (Tzintzuntzan, Tzintzunzita, and Colonia Lazaro Cardenas). A survey questionnaire, which was provided to each individual, included questions about household characteristics, presence of a clay oven in the home, and use of lead oxide ("greta") and other hazardous products. Venous blood samples were obtained from the workers. We found lead exposure to be reduced if the home floor was covered and if the house had been painted < or =1 y prior to study. Blood lead levels exceeded the maximum level permitted, but the levels were lower than those found in the 1970s, during which time study techniques for analyzing samples differed from those used in the present study. In addition, activity patterns of the populations differed during the two studies.

  10. Seroprevalence of Toxoplasma gondii infection in dairy goats in Michoacan, Mexico

    USDA-ARS?s Scientific Manuscript database

    Seroprevalence of Toxoplasma gondii infection in goats in Michoacán, Mexico is largely unknown. Antibodies to T. gondii were determined in 341 dairy goats in Michoacán, Mexico using the modified agglutination test. Goats were raised in 9 farms in 6 municipalities. Overall, antibodies to Toxoplasma w...

  11. Contamination in marine turtle (Dermochelys coriaca) egg shells of Playon de Mexiquillo, Michoacan, Mexico

    SciTech Connect

    Vazquez, G.F.; Reyes, M.C.; Fenandez, G.

    1997-02-01

    Concern for the decreasing population sizes of marine turtles around the world is growing. Potential contamination within habitats of marine turtles, and human activities, such as poaching, modification of nesting sites, and capture of adult turtles, may be responsible for their decreasing populations. Little is known about the baseline levels and physiological effects of environmental contaminants on marine turtle populations. Responding to this concern, the Mexican government has designated areas along the Mexican coastline to preserve marine turtle nesting habitats. {open_quotes}Playon de Mexiquillo{close_quotes}, Michocan, Mexico is one of the coastal preservation areas located near the mouth of Rio la Manzanilla which flows between Sierra Madre del Sur and the Pacific Ocean. Samples of seawater, sand, and marine turtle egg (Dermochelys Coriaca) shells were collected monthly from October, 1992-March, 1993. Contaminants investigated were oil and grease, and metals (cadmium, copper, zinc, nickel, and lead). Seawater samples were collected where the turtles lay eggs in the preservation area and sand samples were taken from the area surrounding the eggs. 12 refs., 1 fig., 4 tabs.

  12. Rock magnetic properties and ore microscopy of the iron ore deposit of Las Truchas, Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Urrutia-Fucugauchi, J.

    1998-02-01

    Iron ore and host rocks have been sampled (90 oriented samples from 19 sites) from the Las Truchas mine, western Mexico. A broad range of magnetic parameters have been studied to characterize the samples: saturation magnetization, Curie temperature, density, susceptibility, remanence intensity, Koenigsberger ratio, and hysteresis parameters. Magnetic properties are controlled by variations in titanomagnetite content, deuteric oxidation, and hydrothermal alteration. Las Truchas deposit formed by contact metasomatism in a Mesozoic volcano-sedimentary sequence intruded by a batholith, and titanomagnetites underwent intermediate degrees of deuteric oxidation. Post-mineralization hydrothermal alteration, evidenced by pyrite, epidote, sericite, and kaolin, seems to be the major event that affected the minerals and magnetic properties. Magnetite grain sizes in iron ores range from 5 to >200 μm, which suggest dominance of multidomain (MD) states. Curie temperatures are 580±5°C, characteristic of magnetite. Hysteresis parameters indicate that most samples have MD magnetite, some samples pseudo-single domain (PSD), and just a few single domain (SD) particles. AF demagnetization and IRM acquisition indicate that NRM and laboratory remanences are carried by MD magnetite in iron ores and PSD-SD magnetite in host rocks. The Koenigsberger ratio falls in a narrow range between 0.1 and 10, indicating the significance of MD and PSD magnetites.

  13. Low frequency (<1Hz) Large Magnitude Earthquake Simulations in Central Mexico: the 1985 Michoacan Earthquake and Hypothetical Rupture in the Guerrero Gap

    NASA Astrophysics Data System (ADS)

    Ramirez Guzman, L.; Contreras Ruíz Esparza, M.; Aguirre Gonzalez, J. J.; Alcántara Noasco, L.; Quiroz Ramírez, A.

    2012-12-01

    We present the analysis of simulations at low frequency (<1Hz) of historical and hypothetical earthquakes in Central Mexico, by using a 3D crustal velocity model and an idealized geotechnical structure of the Valley of Mexico. Mexico's destructive earthquake history bolsters the need for a better understanding regarding the seismic hazard and risk of the region. The Mw=8.0 1985 Michoacan earthquake is among the largest natural disasters that Mexico has faced in the last decades; more than 5000 people died and thousands of structures were damaged (Reinoso and Ordaz, 1999). Thus, estimates on the effects of similar or larger magnitude earthquakes on today's population and infrastructure are important. Moreover, Singh and Mortera (1991) suggest that earthquakes of magnitude 8.1 to 8.4 could take place in the so-called Guerrero Gap, an area adjacent to the region responsible for the 1985 earthquake. In order to improve previous estimations of the ground motion (e.g. Furumura and Singh, 2002) and lay the groundwork for a numerical simulation of a hypothetical Guerrero Gap scenario, we recast the 1985 Michoacan earthquake. We used the inversion by Mendoza and Hartzell (1989) and a 3D velocity model built on the basis of recent investigations in the area, which include a velocity structure of the Valley of Mexico constrained by geotechnical and reflection experiments, and noise tomography, receiver functions, and gravity-based regional models. Our synthetic seismograms were computed using the octree-based finite element tool-chain Hercules (Tu et al., 2006), and are valid up to a frequency of 1 Hz, considering realistic velocities in the Valley of Mexico ( >60 m/s in the very shallow subsurface). We evaluated the model's ability to reproduce the available records using the goodness-of-fit analysis proposed by Mayhew and Olsen (2010). Once the reliablilty of the model was established, we estimated the effects of a large magnitude earthquake in Central Mexico. We built a

  14. Induction of micronuclei and nuclear abnormalities by cyclophosphamide and colchicine in Xenotoca melanosoma (Pisces, Goodeidae) from Lake La Alberca in Michoacan, Mexico.

    PubMed

    Zavala-Aguirre, Jose Luis; Torres-Bugarin, Olivia; Buelna-Osben, Hector Rene; Flores-Kehn, Lola Paulina; Ramos-Ibarra, Maria Luisa; Zuniga-Gonzalez, Guillermo; Ogura, Tetsuya

    2010-01-01

    This study is a follow-up of previous research in which we described the frequency of spontaneous micronucleated erythrocytes (MNE) in the Goodeid Xenotocoa melanosoma collected from Lake La Alberca, located in the state of Michoacan, Mexico. In the present work, we measured micronuclei (MN) and nuclear abnormalities (NA) in erythrocytes of peripheral blood. Bioassays taken at 24 or 96 hours in either the cyclophosfamide (CP) or colchicine (COL) showed a significant increase in MN and BC (P values ranging from 0.0499 to 0.0036) compared with information from wild organisms collected over 3 years. Concentrationdependent and time-dependent responses support the proposal of using endemic Xenotoca melanosoma as a bioindicator of genotoxicity and cytotoxicity with a high transcendence for the health of the entire ecosystem and evaluation of the Lerma-Chapala watershed.

  15. The Northern Boundary of the Michoacan Block: As Inferred From Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Lopez Loera, H.; Fregoso, E.; Maciel Flores, R.; Peña, L.; Alatorre-Zamora, M. A.

    2015-12-01

    The western part of the Guerrero terrane is comprised of the Jalisco and Michoacan Blocks (Rosas-Elguera et al., 1996 and references therein), a fault-bounded crustal blocks at western of Mexico. The Michoacan block is bounded by the N-NE segment of the Rio Balsas in the east, and the Colima graben in the west, the Chapala-Oaxaca fault to the north, and the Middle America Trench to the south. Northern boundary is formed with the Chapala-Oaxaca fault zone (Harrison y Johnson, 1985). The Cotija half-graben is the end-tip of this fault zone. A combined radiometric and paleomagnetic analyses in the Cotija half-graben were carried out (Rosas-Elguera, et al, 2003). Radiometric dates between 31.60 and 8.39 Ma confirm both the southern extension of the Sierra Madre Occidental and the early mafic Tans-Mexican Volcanic Belt succession at the northern part of the Michoacan block. Paleomagnetic data indicate a counterclockwise rotation of ~ 24° about a vertical axis for the Michoacan block. The Michoacan-Guanajuato Volcanic Field forms an area of extensive monogenetic volcanism. This volcanic field contains more than 1000 eruptive centers distributed over an area of 40,000 Km2. The Chapala-Oaxaca fault zone separates the northern MGVF and the southern MGVF. Hasenaka and Carmichael (1987) recognized three different petrologic associations in the MGVF: calc-alkaline rocks typical arc characteristic, K2O-rich alkaline rocks with relatively high MgO contents and TiO2-rich alkaline rocks with relatively low MgO contents. We present the aeromagnetic results (after Consejo de Recursos Minerales, 1999) which suggest a clear relationship between the geologic features and the magnetic response.

  16. Photogeologic and thermal infrared reconnaissance surveys of the Los Negritos-Ixtlan de los Hervores geothermal area, Michoacan, Mexico

    USGS Publications Warehouse

    Gomez, Valle R.; Friedman, J.D.; Gawarecki, S.J.; Banwell, C.J.

    1970-01-01

    New techniques, involving interpretation of panchromatic, ektachrome and ektachrome infrared aerographic photogaphs and thermographic infrared imagery recording emission from the earth's surface in middle and far infrared wavelengths (3-5??m and 8-14??m), are being introduced in geothermal investigations in Mexico to identify outstanding structural and geologic features in a rapid and economical manner. The object of this work is to evaluate the new airborne infrared techniques and equipment as a complement to the data obtained from panchromatic aerial photography. This project is part of the Mexican remote sensing program of natural resources carried out under the auspices of the Comision Nacional del Espacio Exterior and in which the Research Institute (Instituto de Investigaciones de la Industria Electrica) is actively participating. The present study was made cooperatively with the U.S. National Aeronautics and Space Administration and the U.S. Geological Survey. The Los Negritos-Ixtlan de los Hervores geothermal fields are located east of Lake Chapala at the intersection of the Sierra Madre occidental and the west-central segment of the neovolcanic axis of Mexico. The two principal zones of hydrothermal activity occur in a tectonic trench filled with lake sediments of the Quaternary intercalated with Quaternary and Holocene volcanic rocks and characterized by an intricate system of block-fault tectonics, part of the Chapala-Acambay tectonic system, along which there has been volcanic activity in modern time. Surface manifestations of geothermal activity consist of relatively high heat flow and hot springs, small geysers and small steam vents aligned along an E-W axis at Ixtlan, possibly at the intersection of major fault trends and mud volcanoes and hot pools aligned NE-SW at Los Negritos. More than 20 exit points of thermal waters are shown on infrared imagery to be aligned along an extension of the Ixtlan fault between Ixtlan and El Salitre. A narrow zone of

  17. Effects of Selective Logging on Birds in the Sierra de Coalcoman, Sierra Madre del Sur, Michoacan, Western Mexico

    Treesearch

    Jose Fernando Villaseñor; Neyra Sosa; Laura Villaseñor

    2005-01-01

    In order to determine the effects of selective logging on pine-oak forest?s bird communities in central-western Mexico, we gathered information through 10-min point counts in plots without wood extraction and sites logged at different times in the past (1, 4, and 8 years). We did not find evidences to argue for effects of logging on bird communities; the study plots...

  18. Diversity, local knowledge and use of stingless bees (Apidae: Meliponini) in the municipality of Nocupétaro, Michoacan, Mexico

    PubMed Central

    2014-01-01

    Background Stingless bees were significant resources managed by Mesoamerican peoples during pre-Columbian times and remain important in particular areas. Our study aimed at inventorying stingless bees’ species, traditional knowledge and forms of use and management of them at the municipality of Nocupetaro, Michoacán, Mexico, a region of the Balsas River Basin. Methods We inventoried the stingless bees of the municipality of Nocupétaro, Michoacán, México, through extensive collecting of bee specimens in different vegetation types. We then conducted semi-structured interviews to local experts in order to document their knowledge and management techniques of stingless bees’ species. Results We identified a total of eight stingless bees’ species in the study area as well as three additional unidentified taxa recognized by people through the local names. Our inventory included one new record of species for the region (Lestrimelitta chamelensis Ayala, 1999). The taxa identified are all used by local people. Scaptotrigona hellwegeri Friese, 1900; Melipona fasciata Latreille, 1811; Frieseomelitta nigra Cresson, 1878 and Geotrigona acapulconis Strand, 1919 are particularly valued as food (honey), medicinal (honey and pollen), and material for handcrafts (wax). All species recorded are wild and their products are obtained through gathering. On average, local experts were able to collect 4 nests of stingless bees per year obtaining on average 6 L of honey and 4 Kg of wax but some came to collect up 10–12 hives per year (18 L of honey and 24 Kg of wax). Conclusions Local knowledge about use, management and ecological issues on stingless bees is persistent and deep in the study area. Information about this group of bees is progressively scarcer in Mexico and significant effort should be done from ethnobiological and ecological perspectives in order to complement the national inventory of bee resources and traditional knowledge and management of them. PMID:24903644

  19. Diversity, local knowledge and use of stingless bees (Apidae: Meliponini) in the municipality of Nocupétaro, Michoacan, Mexico.

    PubMed

    Reyes-González, Alejandro; Camou-Guerrero, Andrés; Reyes-Salas, Octavio; Argueta, Arturo; Casas, Alejandro

    2014-06-05

    Stingless bees were significant resources managed by Mesoamerican peoples during pre-Columbian times and remain important in particular areas. Our study aimed at inventorying stingless bees' species, traditional knowledge and forms of use and management of them at the municipality of Nocupetaro, Michoacán, Mexico, a region of the Balsas River Basin. We inventoried the stingless bees of the municipality of Nocupétaro, Michoacán, México, through extensive collecting of bee specimens in different vegetation types. We then conducted semi-structured interviews to local experts in order to document their knowledge and management techniques of stingless bees' species. We identified a total of eight stingless bees' species in the study area as well as three additional unidentified taxa recognized by people through the local names. Our inventory included one new record of species for the region (Lestrimelitta chamelensis Ayala, 1999). The taxa identified are all used by local people. Scaptotrigona hellwegeri Friese, 1900; Melipona fasciata Latreille, 1811; Frieseomelitta nigra Cresson, 1878 and Geotrigona acapulconis Strand, 1919 are particularly valued as food (honey), medicinal (honey and pollen), and material for handcrafts (wax). All species recorded are wild and their products are obtained through gathering. On average, local experts were able to collect 4 nests of stingless bees per year obtaining on average 6 L of honey and 4 Kg of wax but some came to collect up 10-12 hives per year (18 L of honey and 24 Kg of wax). Local knowledge about use, management and ecological issues on stingless bees is persistent and deep in the study area. Information about this group of bees is progressively scarcer in Mexico and significant effort should be done from ethnobiological and ecological perspectives in order to complement the national inventory of bee resources and traditional knowledge and management of them.

  20. Michoacan People, Customs, and the Day of the Dead.

    ERIC Educational Resources Information Center

    Maulhardt, Mary

    This curriculum guide is intended: (1) to expose students to the people and customs of Michoacan, Mexico; (2) to explore the meaning of traditional Day of the Dead customs through hands-on experiences; and (3) to build the self-esteem of second language learners of Mexican descent. During the study, students whose primary language is Spanish read…

  1. Bioaccumulation of microcystins by fish associated with a persistent cyanobacterial bloom in Lago de Patzcuaro (Michoacan, Mexico).

    PubMed

    Berry, John P; Lee, Elisha; Walton, Katherine; Wilson, Alan E; Bernal-Brooks, Fernando

    2011-07-01

    Lago de Patzcuaro is a historically important freshwater fishery in Mexico. The lake is presently characterized by a persistent bloom of cyanobacteria, specifically dominated by recognized producers of toxic microcystins (MCYSTs). We evaluated MCYSTs in sestonic and dissolved fractions of the water column, as well as representative fish species (silversides, Chirostoma spp.; Goodea sp.; and carp, Cyprinus carpio) obtained from local markets and small commercial catches during the bloom. Samples were evaluated primarily by enzyme-linked immunosorbent assay (ELISA), and secondarily by protein phosphatase (PPase) inhibition assay and liquid chromatography-mass spectrometry (LC-MS). Sestonic MCYST concentration (0.02-0.36 µg/L) generally correlated inversely with distance from the bloom, supporting the bloom as the source of the toxin. Several MCYST variants, including MC-LR, -LA and -LY, as well as didemethyl variants, were identified by LC-MS/MS analysis. All three species of fish bioaccumulated MCYSTs in relevant tissues, and toxin content correlated with trophic level, with highest and lowest levels measured in phytoplanktivorous and zooplanktivorous representatives, respectively. Detection of MCYST in silversides and Goodea sp. is particularly relevant because both are consumed in their entirety, including viscera (e.g., liver) known to primarily accumulate MCYST. These results indicate that Lago de Patzcuaro is indeed characterized by a toxigenic bloom, and that commercially important fish species from the lake accumulate toxic MCYST in tissues relevant to human consumption. As such, this system may represent an ideal model of the trophic transfer of MCYSTs and its relevance to human and environmental health.

  2. Self-similar clustering of cinder cones and crust thickness in the Michoacan-Guanajuato and Sierra de Chichinautzin volcanic fields, Trans-Mexican Volcanic Belt

    NASA Astrophysics Data System (ADS)

    Mazzarini, Francesco; Ferrari, Luca; Isola, Ilaria

    2010-04-01

    The spatial clustering of basaltic vents in monogenetic volcanic fields has been used as a proxy for crustal thickness in extensional and back-arc tectonic settings. The basaltic vents have a fractal clustered distribution (self-similar clustering) described by a power-law. The power-law is defined over a range, the size range of the distribution, of values (in this case the vents' separation) delimited by a lower and an upper cut-offs. Here we apply the fractal clustering analysis to the two largest monogenetic volcanic fields of the Trans-Mexican Volcanic Belt (TMVB), a continental arc built on different crustal terranes. The Michoacan-Guanajuato volcanic field (MGVF), located in the central-western TMVB, includes over 1000 vents of late Pliocene to Quaternary age, built on attenuated crust of Mesozoic to Tertiary age. The Sierra de Chichinautzin volcanic field (SCVF), in the central-eastern TMVB, is composed of ~ 220 Late Pleistocene to Holocene vents laying above thicker crust of Precambrian to Tertiary age. Monogenetic vents in both volcanic fields show self-similar clustering with fractal exponent D = 1.67 in the range 1.3-38 km (MGVF) and D = 1.56 in the range 1.5-32 km (SCVF). The upper cut-off (Uco) for the power-law distribution of the MGVF well fits the crustal thickness below the volcanic field as derived from independent geophysical data. The Uco value of SCVF indicates a crust thickness of about 32 km, this value is in agreement with new geophysical data that indicate magma underplating the crust beneath the volcanic field area.

  3. Is The Chapala-Oaxaca Fault The Souhtern Boundary of the Michoacan-Guanajuato Volcanic Field As inferrred From Magnetic data?

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Lopez-Loera, H.; Fregoso, E.; Flores, R. M., Sr.; Peña, L.

    2016-12-01

    On the basis of previous structural and new geophysical data, we propose that: (1) the continental boundaries of the Michoacan block are early structures reactivated since the Pliocene to Quaternary contributing to development of volcanism along it and (2) previously, Rosas-Elguera et al. (1996) proposed that Pliocene-Quaternary extensional faulting at the western edge of Michoacan block is a basement-controlled intraplate deformation related to plate boundary forces rather than to active continental rifting. Here we propose the NW boundary is formed by three segments: the Cotija half-graben, the Paricutin zone and the Jorullo zone.

  4. [Counseling for HPV detection when used to screen for cervical cancer: a qualitative study on the needs of women from Michoacan, Mexico].

    PubMed

    León-Maldonado, Leith; Allen-Leigh, Betania; Lazcano-Ponce, Eduardo

    2014-01-01

    To explore the information and counseling needs of a group of Mexican women during use of the HPV test. In 2011, 24 semistructured interviews were done with women upon receiving HPV test results in two municipalities in the state of Michoacan. Qualitative analysis of the interviews was done using constant comparison techniques. During their use of screening services women received limited counseling; they felt anguish and confusion. Women were interested in receiving information and advice on HPV and cervical cancer, the meaning of test result, next steps to be taken in their healthcare use as well as information and emotional support related to the sexual transmission of HPV. The design and implementation of policies are needed which instigate health education and counseling in conjunction with HPV testing.

  5. On the nature of regional seismic phases-III. The influence of crustal heterogeneity on the wavefield for subduction earthquakes: the 1985 Michoacan and 1995 Copala, Guerrero, Mexico earthquakes

    NASA Astrophysics Data System (ADS)

    Furumura, T.; Kennett, B. L. N.

    1998-12-01

    The most prominent feature of the regional seismic wavefield from about 150 to over 1000 km is usually the Lg phase. This arrival represents trapped S-wave propagation within the crust as a superposition of multiple reflections, and its amplitude is quite sensitive to the lateral variation in the crust along a propagation path. In an environment where the events occur in a subduction zone, such as the western coast of Mexico, quite complex influences on the character of the regional wavefield arise from the presence of the subduction zone. The great 1985 Michoacan earthquake (MW=8.1), which occurred in the Mexican subduction zone, was one of the most destructive earthquakes in modern history and its notable character was that at Mexico City, located over 350 km from the epicentre, there was strong ground shaking almost comparable to that in the epicentral region that lasted for several minutes. Considerable effort has been expended to explain the origin of the unusual observed waves that caused the severe damage in the capital city during the destructive earthquake. The nature of the propagation process in this region can be understood in part by using the detailed strong-motion records from the 1995 Copala, Guerrero (MW=7.4) earthquake near the coast to the south of Mexico City, which also had an enhanced amplitude in the Valley of Mexico. Numerical modelling of both P and S seismic waves in 2-D and 3-D heterogeneous crustal models for western Mexico using the pseudospectral method provides direct insight into the nature of the propagation processes through the use of sequences of snapshots of the wavefield and synthetic seismograms at the surface. A comparison of different models allows the influences of different aspects of the structure to be isolated. 2-D and 3-D modelling of the 1985 Michoacan and 1995 Copala earthquakes clearly demonstrates that the origin of the long duration of strong ground shaking comes from the Sn and Lg wave trains. These S

  6. Mexico's giant fields, 1978-1988 decade

    SciTech Connect

    Acevedo, J.S.; Pemex, A.B.S.

    1990-09-01

    Twenty giant oil and gas fields were discovered in Mexico during the period of 1978-1988. The fields, located in adjacent areas, are described in terms of stratigraphy, tectonics, and general characteristics of the reservoirs. Production and reserves figures are also included. The two main oil productive areas in Mexico, Chiapas-Tabasco and offshore Campeche Sound, contribute 92% of Mexico's Mesozoic production. Production comes from Upper Jurassic carbonates; Cretaceous calcareous breccias, limestones, and dolomites; and from lower Paleocene calcareous breccias. The fields represented include 11 from the Chiapas-Tabasco area (Agave, Paredon, Iris, Giraldas, Cardenas, Jujo, Bellota, Tecominoacan, Muspac, Sen, and Luna) and nine from the the Campeche Sound area (Abkatun, Ku, Chuc, Ek, Pol, Malob, Caan, Uech, and Batab).

  7. Geothermal Field Development in Mexico

    SciTech Connect

    Espinosa, Hector Alonso

    1983-12-15

    Mexico is a Country characterized by its diversified means of Power Gerneration. Actual installed capacity is almost 19000 MW, of which 205 MW corresponds to Geothermal Plants, that is, 180 MW in Cerro Prieto and 25 MW of Portable Plants in Los Azufres. To date, 346 area with exploitation possibilites, are known. They are mainly distributed along the Volcanic Belt where the most prominent are, Los Azufres, La Primavera, Los Humeros, Ixtlan De Los Hervores and Los Negritos, among others. Proved reserves are 920 MW, and the accessible resource base are 4600 MW identified and 6000 MW undiscovered. The long range construction studies intends to achieve a total installed capacity of 100000 MW, by the end of this century, including 2000 MW Geothermal, through conventional and Portable Plants. It is not a definite program but a development strategy. The carrying out of a definite program, will depend upon the confirmation of Hypothesis made in previous studies, and the economic decisions related to the financial sources availability, and techologies to be used in the future as well.

  8. Space Radar Image of Pinacate Volcanic Field, Mexico

    NASA Image and Video Library

    1999-04-15

    This spaceborne radar image shows the Pinacate Volcanic Field in the state of Sonora, Mexico, about 150 kilometers 93 miles southeast of Yuma, Arizona. The United States/Mexico border runs across the upper right corner of the image.

  9. An integrated geochronology and paleomagnetic study from Michoacan Block: tectonic implications for the Guadalajara triple junction

    NASA Astrophysics Data System (ADS)

    Rosa-Elguera, J.; Gogichaishvili, A.; Alva-Valdivia, L.; Urrutia-Fucugauchi, J.

    2002-12-01

    Three alternatives were proposed to expain the Guadalajara triple junction: (a) mantle plume beneath Guadalajara area provoking a regional uplifting, (b) relocation of the East Pacific Rise, and (c) transfer to the SE of rifting-related structure of the California Gulf. However, a different interpretation can be advanced if we consider the tectonics of the northern-Colima and western-Chapala rifts together with counterclockwise rotation of the Michoacan block. We carried out a detailed tectonic and paleomagnetic analysis along the Chapala rift and the Michoacan block. The trend of the measured mesofaults in the Chapala rift displays a dominant E-W direction. These faults represent everywhere the last tectonic event corresponding to Late Miocene to Quaternary times. Western Chapala rift is formed with three normal faults southward dipping which form a "domino-like" fault system. The most southern block of this system is a gently NW-tilted volcanic plateau of Early Pliocene basaltic rocks which belongs to the NW-part of the Michoacan block. Although some faults present a lateral component of motion, the great majority of them have pitches higher than 45° and dip ranging between 45° and 75°. Paleo-stress tensors computed from fault slip data measured at twelve sites in the Chapala rift indicate that average direction of the minimum principal stress is 160°. Paleomagnetic and geochronological sampling were carried out on the Cotija area (nothern part of the of the Michoacan block). Oldest studied rock gave an age of 9.17 +/- 0.92 Ma, whereas youngest one, located above the ancient fault zone, is 3.8 Ma old. A total of 65 oriented samples (12 sites) from the late Miocene lava flows were collected from Cotija area for paleomagnetic analyses. Typically, 5 to 6 samples per flow were subjected to alternating magnetic field treatment. Most sites are characterized by normal polarity and stable single component magnetizations. The Michoacan block yield the mean

  10. Giant fields in the southeast of Mexico

    SciTech Connect

    Acevedo, J.S.; Dautt, O.M.

    1980-01-01

    From a geologic and petroliferous point of view, the southeast zone coastal plain of Mexico has been divided into the saline basin of the Isthmus, the Macuspana Basin, and the Chiapas-Tabasco Mesozoic area. In the first 2 basins, there are giant producer fields from tertiary sands. In the saline basin of the Isthmus, production comes from structural traps associated with saline domes. In the Macuspana Basin, production comes from anticlines. The Chiapas-Tabasco Mesozoic area produces from Jurassic, Lower, Middle and Upper Cretaceous dolomitic limestones and dolomites associated with anticlines. The marine platform of Campeche produces from Jurassic and Cretaceous dolomites and lower Paleocene dolomitic Breccias associated with anticlines having numerous normal and thrust faults. A brief description is given of 5 giant fields in the saline basin of the Isthmus and 3 fields in the Macuspana Basin; a more detailed description is given of 4 giant fields in the Chiapas-Tabasco area and 2 in the sound of Campeche.

  11. Ecological protection in the Las Tres Virgenes, Mexico, geothermal field

    SciTech Connect

    Zirahuen Ortega Varela, J.R.

    1996-12-31

    The programs of environmental protection designed by Comision Federal de Electricidad are described in a general way. These programs detect, avoid, soften and compensate the environmental impacts product of the exploration, construction and operation activities of the geothermal field Las Tres Virgenes, this field is in the buffer zone of the biosphere reserve {open_quotes}El Vizcaino{close_quotes} at the north of the State of Baja California Sur, Mexico.

  12. Crust and subduction zone structure of Southwestern Mexico

    NASA Astrophysics Data System (ADS)

    Suhardja, Sandy Kurniawan; Grand, Stephen P.; Wilson, David; Guzman-Speziale, Marco; Gomez-Gonzalez, Juan Martin; Dominguez-Reyes, Tonatiuh; Ni, James

    2015-02-01

    Southwestern Mexico is a region of complex active tectonics with subduction of the young Rivera and Cocos plates to the south and widespread magmatism and rifting in the continental interior. Here we use receiver function analysis on data recorded by a 50 station temporary deployment of seismometers known as the MARS (MApping the Rivera Subduction zone) array to investigate crustal structure as well as the nature of the subduction interface near the coast. The array was deployed in the Mexican states of Jalisco, Colima, and Michoacan. Crustal thickness varies from 20 km near the coast to 42 km in the continental interior. The Rivera plate has steeper dip than the Cocos plate and is also deeper along the coast than previous estimates have shown. Inland, there is not a correlation between the thickness of the crust and topography indicating that the high topography in northern Jalisco and Michoacan is likely supported by buoyant mantle. High crustal Vp/Vs ratios (greater than 1.82) are found beneath the trenchward edge of magmatism including below the Central Jalisco Volcanic Lineament and the Michoacan-Guanajuato Volcanic Field implying a new arc is forming closer to the trench than the Trans Mexican Volcanic Belt. Elsewhere in the region, crustal Vp/Vs ratios are normal. The subducting Rivera and Cocos plates are marked by a dipping shear wave low-velocity layer. We estimate the thickness of the low-velocity layer to be 3 to 4 km with an unusually high Vp/Vs ratio of 2.0 to 2.1 and a drop in S velocity of 25%. We postulate that the low-velocity zone is the upper oceanic crust with high pore pressures. The low-velocity zone ends from 45 to 50 km depth and likely marks the basalt to eclogite transition.

  13. Inversion for slip distribution using teleseismic P waveforms: North Palm Springs, Borah Peak, and Michoacan earthquakes

    USGS Publications Warehouse

    Mendoza, C.; Hartzell, S.H.

    1988-01-01

    We have inverted the teleseismic P waveforms recorded by stations of the Global Digital Seismograph Network for the 8 July 1986 North Palm Springs, California, the 28 October 1983 Borah Peak, Idaho, and the 19 September 1985 Michoacan, Mexico, earthquakes to recover the distribution of slip on each of the faults using a point-by-point inversion method with smoothing and positivity constraints. Results of the inversion indicate that the Global digital Seismograph Network data are useful for deriving fault dislocation models for moderate to large events. However, a wide range of frequencies is necessary to infer the distribution of slip on the earthquake fault. Although the long-period waveforms define the size (dimensions and seismic moment) of the earthquake, data at shorter period provide additional constraints on the variation of slip on the fault. Dislocation models obtained for all three earthquakes are consistent with a heterogeneous rupture process where failure is controlled largely by the size and location of high-strength asperity regions. -from Authors

  14. [Nutritional risk factors in patients with head and neck cancer in oncology care center Michoacan state].

    PubMed

    García Rojas Vázquez, L E; Trujano-Ramos, L A; Pérez-Rivera, E

    2013-01-01

    The head and neck cancer in Michoacán, Mexico, ranks as the third most common cancer and accounts for 12% of deaths. The increase in malnutrition in a patient with this disease has been associated with increased mortality. We studied prospectively 30 patients of both sexes, aged 18 years with head and neck cancer in the Cancer Care Center of Michoacan. In the evaluation period since August 2010 to August 2011. Formats were used VGS-Oncology (Subjective Global Assessment), NRS 2002 (Nutritional risk screen) and Guss (Gugging Swallowing Screen), through which nutritional risk was determined, and established the swallowing capacity of the study population. In our study, 53.3% of the population had moderate malnutrition according to the VGS Oncology, 33% weight loss record. The NRS 2002 show that 43.3% is at risk of malnutrition. The degree of dysphagia is shown more often in older patients, cancer type and stage of illness. Nutritional risk scales relate directly proportional to tumor location and stage, as well, there are other different oncological factors involved in the patient's nutritional deterioration. Therefore it is of vital importance to have a nutritionist as part of the multidisciplinary team, to detect the nutritional risk and to be able to handle it in an opportune way. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  15. Geothermal Fields on the Volcanic Axis of Mexico

    SciTech Connect

    Mercado, S.; Gonzalez, A.

    1980-12-16

    At present in Mexico, geothermal energy is receiving a great impulse due to the excellent results obtained in the Cerro Prieto geothermal field, in which a geothermoelectric plant is operated. This plant has four units of 37.5 MW each, with a total capacity of 150 MW, and under program 470 MW more by 1984. The Government Institution, Comisi6n Federal de Electricidad, is in charge of the exploration and exploitation of geothermal fields as well as construction and operation of power plants in Mexico. By this time CFE has an extensive program of exploration in the central part of Mexico, in the Eje Neovolcdnico. In this area, several fields with hydrothermal alteration are under exploration, like the Michoac6n geothermal area, where Los Azufres geothermal field is being developed. Seventeen wells have been drilled and twelve of them presented excellent results, including two dry steam wells. In other areas, such as Arar6, Cuitzeo, San Agustln del Maiz,Ixtldn de Los Hervores and Los Negritos, geological, geophysical and geochemical explorations have been accomplished, including shallow well drilling with good results. Another main geothermal area is in the State of Jalisco with an extension of 5,000 m2, where La Primavera geothermal field shows a lot of volcanic domes and has an intensive hydrothermal activity. Deep wells have been drilled, one of them with a bottom temperature of 29OOC. Other fields in this area, like San Narcos, Hervores de La Vega, La Soledad, Villa Corona, etc., have a good geothermal potential. A new geothermal area has been explored recently in the eastern part of the country named Los Humeros, Puebla. In this area studies are being made and there are plans for well drilling exploration by the beginning of 1981. Like this one, there are many other areas in the country in which 300 hydrothermal alteration zones are been classified and 100 of them are considered economically exploitable.

  16. Mexico.

    ERIC Educational Resources Information Center

    Semaan, Leslie

    The text explores Mexico's history, geography, art, religion, and lifestyles in the context of its complex economy. The text focuses on Mexico's economy and reasons for its current situation. Part I of this teaching unit includes: Teacher Overview, Why Study Mexico, Mexico Fact Sheet, Map of Mexico, the Land and Climate, History, Government,…

  17. Managing US-Mexico "border health": an organizational field approach.

    PubMed

    Collins-Dogrul, Julie

    2006-12-01

    During World War II Mexican and US health professionals and organizations constructed a transnational organizational field to manage the border's public health problems. Despite barriers to inter-organizational cooperation, including disparate administrative structures and North-South stratification, the field's transnational approach to health on the border has continued for 60 years. Using archival data to track changes in the number and types of organizations, this article argues that the field practitioners call "border health" reconfigured during the North American Free Trade Association (NAFTA) decade from an era of loosely organized professionals to a specialized bureaucracies era. This change brought new vitality to border health, with transnational ties increasing and diversifying, but has not weakened entrenched cross-border inequalities. The organizational history of the US-Mexico border health field demonstrates how macro-politics and inter-organizational stratification shape transnational public health problems.

  18. Stress Field and Seismicity in the Basin of Mexico

    NASA Astrophysics Data System (ADS)

    Huesca-Perez, E.; Quintanar, L.; Garcia-Palomo, A.

    2007-12-01

    Mexico City is located in the basin of Mexico, inside the so called Trans-Mexican Volcanic Belt. The region in general and the basin in particular, is characterized by local low magnitude seismicity (Mc < 4.0) that may represent a risk to the city due of the nearness from epicenters. We can distinguish three main areas of local activity: 1).- surrounding the old basin of Texcoco lake, 2)- Chalco and 3)- Juchitepec - Milpa Alta outside Mexico City; the rest of the basin presents lower seismic activity. We recorded and located 336 earthquakes with digital seismograms between 1996 and 2007. From them, just 23 focal mechanisms could be evaluated because of low magnitude that creates recording problems in the seismological networks and high frequency background noise. The focal mechanisms are mainly strike-slip and dip-slip (normal) faulting. We used three different techniques (when possible) to calculate the focal mechanisms: simple and composite first motion focal mechanism, Hash's S/P amplitude rate focal mechanism and time domain moment tensor inversion using broadband three components seismograms. The final goal is to find the local and regional stress field for the whole basin.

  19. First report of leaf rust of blueberry caused by Thekopsora minima in Mexico

    USDA-ARS?s Scientific Manuscript database

    Blueberry (Vaccinium corymbosum L.) is becoming an important crop in the states of Jalisco and Michoacan in Mexico. As the area under blueberry cultivation increases, new diseases causing severe losses are appearing. Leaf rust is one of the most destructive diseases of blueberry in Mexico. Sori on t...

  20. New Mexico gas plant operator automates field control

    SciTech Connect

    Trosper, R.L. ); Stubbs, R.G. ); Carver, D. )

    1994-03-07

    GPM Gas Corp., Houston, a subsidiary of Phillips Petroleum Co., has implemented a field automation control system (FACS) that allows company operators remotely to monitor natural-gas operations in GPM's New Mexico region. The system has helped improve operating efficiencies and reduce staffing. Operators can now accurately monitor and control gas gathering, booster, and plant operations. The systems allows remote monitoring and measuring of gas flow rates, temperatures, and pressures from the wellhead through processing. Producers who sell gas into GPM's systems now have access to real-time production information through telephone or facsimile for each individual meter station connected to their well sites.

  1. Wood and fruit drying in Los Azufres geothermal field, Mexico

    SciTech Connect

    Casimiro, E.; Pastrana, E.

    1996-12-31

    The main object of Comision Federal de Electricidad (CFE`s) Geothermal Field at Los Azufres, is to generate geothermal electricity; however with the new politics in Mexico CFE has built a pilot project in order to profit from the geothermal residual energy and to attract national or foreign investors and convince them that direct-use of geothermal energy is an attractive feasible and economical possibility. The object of this paper is to present the CFE experiences in wood and fruit drying using geothermal energy.

  2. Aflatoxin synthesis in corn fields in Guanajuato, Mexico.

    PubMed

    Bucio-Villalobos, C M; Guzmán-de-Peña, D; Peña-Cabriales, J J

    2001-06-01

    Aflatoxin contamination of corn is an important problem internationally, particularly in tropical and subtropical conditions that favor infection and synthesis by Aspergillus. Environmental conditions (drought) and agronomic practices i.e. N fertilization have been reported as favorable to aflatoxin synthesis in the field. This study was undertaken to investigate whether the contamination of corn commonly observed in stored conditions in this important corn producing region of Mexico known as "El Bajio" is related to infection by Aspergillus under field conditions. Results using three corn hybrids of recognized susceptibility to infection showed that corn ears artificially inoculated in the field with a toxigenic strain of Aspergillus parasiticus presented a low content of aflatoxin ranging from 13.6 to 24.7 microg Kg(-1). No significant differences were observed between the hybrids tested. Similarly, N fertilization practices, 260 Kg N ha(-1), applied at sowing did not have an effect on the extent of the contamination observed of 6.2 and 19.3 mg of aflatoxin kg(-1) in natural infected and inoculated samples with A. parasiticus NRRL 2999, respectively. Our data suggest that the cases of aflatoxin contamination of corn in this part of Mexico are not related to infection occurring during the crops growing period but most probably to poor storage conditions of corn.

  3. Coordinated Field Campaigns in Chesapeake Bay and Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Novak, Michael; Tzortziou, Maria A.

    2015-01-01

    NASA's GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission concept recommended by the U.S. National Research Council (2007) focuses on measurements of atmospheric trace gases and aerosols and aquatic coastal ecology and biogeochemistry from geostationary orbit (35,786 km altitude). Two GEO-CAPE-sponsored multi-investigator ship-based field campaigns were conducted to coincide with the NASA Earth Venture Suborbital project DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaigns: (1) Chesapeake Bay in July 2011 and (2) northwestern Gulf of Mexico in September 2013. Goal: to evaluate whether GEO-CAPE coastal mission measurement and instrument requirements are optimized to address science objectives while minimizing ocean color satellite sensor complexity, size and cost - critical mission risk reduction activities. NASA continues to support science studies related to the analysis of data collected as part of these coordinated field campaigns and smaller efforts.

  4. Ancient Mudflows in the Tuxtla Volcanic Field, Veracruz, Mexico

    NASA Astrophysics Data System (ADS)

    Espindola, J.; Zamora-Camacho, A.; Godinez, M.

    2011-12-01

    The Tuxtla Volcanic Field (TVF) is a basaltic volcanic enclave in eastern Mexico at the margin of the Gulf of Mexico. Due to the high rates of precipitation floods and mudflows are common. Resulting from a systematic study of geologic hazard in the TVF we found several mudflow deposits that impacted pre-Columbian settlements. Sections of the deposits were observed in detail and sampled for granulometric studies. The deposits contained materials suitable for dating: ceramic shards and some of them charcoal fragments. Shards from the interior of the deposit were collected and placed in black bags to prevent the action of light and to be analyzed by thermoluminiscense (TL), the charcoal samples were dated using standard radiocarbon methods (C-14). The sites were dubbed La Mojarra (18°37.711', 95°18.860'), Revolución (18° 35.848', 95°11.412'), Pisatal (18°36.618', 95°10.634'), and Toro Prieto (18°38.229, 95°12.037'). These places were named after the nearby villages the first two, lake Pisatal the third and Toro Prieto creek the fourth. All the deposits occur close to the margins of riverbeds or lakes. Samples of these sites yielded ages of 1176±100 (TL), 1385±70 (C-14), 1157±105 (TL), 2050+245-235 (C-14), respectively. These locations have undergone recurrent floods in the last decades, showing that these phenomena impact the same areas over centuries. The dates mentioned are important because, no vestiges of human settlements had been reported in the area, which in the past was covered by a dense forest. The settlements must have been very small and depended of such cities as nearby Matacapan an important city with strong ties to Teotihuacán in central Mexico. The ages agree with the findings of archeologic studies in Matacapan, which indicate that the population became increasingly ruralized since the late classic period (≈ 600-800 AD).

  5. Space Radar Image of Pinacate Volcanic Field, Mexico

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the Pinacate Volcanic Field in the state of Sonora, Mexico, about 150 kilometers (93 miles) southeast of Yuma, Arizona. The United States/Mexico border runs across the upper right corner of the image. More than 300 volcanic vents occur in the Pinacate field, including cinder cones that experienced small eruptions as recently as 1934. The larger circular craters seen in the image are a type of volcano known as a 'maar', which erupts violently when rising magma encounters groundwater, producing highly pressurized steam that powers explosive eruptions. The highest elevations in the volcanic field, about 1200 meters (4000 feet), occur in the 'shield volcano' structure shown in bright white, occupying most of the left half of the image. Numerous cinder cones dot the flanks of the shield. The yellow patches to the right of center are newer, rough-textured lava flows that strongly reflect the long wavelength radar signals. Along the left edge of the image are sand dunes of the Gran Desierto. The dark areas are smooth sand and the brighter brown and purple areas have vegetation on the surface. Radar data provide a unique means to study the different types of lava flows and wind-blown sands. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 18, 1994. The image is 57 kilometers by 48 kilometers (35 miles by 30 miles) and is centered at 31.7 degrees north latitude, 113.4 degrees West longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  6. Neogene rhyolites of the northern Jemez volcanic field, New Mexico

    SciTech Connect

    Loeffler, B.M.; Vaniman, D.T.; Baldridge, W.S.; Shafiqullah, M.

    1988-06-10

    Volcanic centers previously mapped as the 20 Ma El Rechuelos Rhyolite in the northern Jemez volcanic field, New Mexico, include three distinct episodes of rhyolitic volcanism. An early (7.5 Ma) extrusive dome of flow-banded biotite rhyolite and an intermediate (5.8 Ma) rhyolite, possibly a volcanic neck, correspond in age to rhyolites of the Keres Group in the southern Jemez volcanic field. Three other extrusive domes of aphyric, pumiceous rhyolite and obsidian comprise a late volcanic episode, dated at 2.0 Ma. We retain the name El Rechuelos Rhyolite only for these late centers. Another center, farther north than the others but previously mapped with the El Rechuelos Rhyolite, is a dacite pumice ring whose age (5.2 Ma), petrography, major- and trace-element chemistry, and Sr initial ratio all suggest it should be included with rocks of the Tschicoma Formation. Nd and Sr isotopic ratios of the Neogene rhyolites of the northern Jemez volcanic field suggest that these rhyolites were not produced by partial melting of either upper or lower crust. Rather, they may have been generated from a mantle-derived mafic magma, such as the nearby Lobato Basalt, by fractional crystallization with concomitant assimilation of small amounts (<6%) of lower crust. If the El Rechuelos is derived from a lower crust magma chamber, as seems likely, then it is not related to the bandelier magma system, even though it is part of a continuum of rhyolite volcanism ranging from 3.6 Ma to 130,000 years ago that includes the Bandelier and precursor rhyolitic units. copyright American Geophysical Union 1988

  7. Magnetotelluric data, Taos Plateau Volcanic Field, New Mexico

    USGS Publications Warehouse

    Ailes, Chad E.; Rodriguez, Brian D.

    2010-01-01

    The population of the San Luis Basin region of northern New Mexico is growing. Water shortfalls could have serious consequences. Future growth and land management in the region depend on accurate assessment and protection of the region's groundwater resources. An important issue in managing the groundwater resources is a better understanding of the hydrogeology of the Santa Fe Group and the nature of the sedimentary deposits that fill the Rio Grande rift, which contain the principal groundwater aquifers. The shallow unconfined aquifer and the deeper confined Santa Fe Group aquifer in the San Luis Basin are the main sources of municipal water for the region. The U.S. Geological Survey (USGS) is conducting a series of multidisciplinary studies of the San Luis Basin. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys, an electromagnetic survey called magnetotellurics (MT), and hydrologic and lithologic data are being used to better understand the aquifers. This report describes a regional east-west MT sounding profile acquired in late July 2009 across the Taos Plateau Volcanic Field where drillhole data are sparse. Resistivity modeling of the MT data can be used to help map changes in electrical resistivity with depths that are related to differences in rock types. These various rock types help control the properties of aquifers. The purpose of this report is to release the MT sounding data collected along the east-west profile. No interpretation of the data is included.

  8. Microseismic monitoring of the Chaveroo oil field, New Mexico

    SciTech Connect

    Rutledge, J.T.; Albright, J.N.; Fairbanks, T.D.; Murphy, M.B.; Roberts, P.M.

    1990-01-01

    Induced microseismicity was monitored in the Chaveroo oil field in southeastern New Mexico during a pressurized stimulation of a well being prepared as an injector for a waterflood operation. In addition, the microseismicity was monitored for 5 weeks following the stimulation while the area was under normal waterflood production. Little seismicity was detected during the 5.5 hour stimulation in which three thousand barrels of water were injected into the reservoir at pressures ranging from 96 to 257 bars in excess of hydrostatic pressure. Intermittent monitoring over the 5-week period indicated detectable seismicity occurred during waterflood production. Monitoring during the 5 weeks, however, was not complete enough to draw general conclusions on temporal variations of observed microseismicity. Seventy-three good quality events recorded over a cumulative 24 hours of intermittent monitoring were located using the hodogram technique. Events were detected at distances up to 1700 m from the monitor well but most occurred within 900 m. The map of microearthquake locations indicated that events occurred in the vicinity of producing wells and away from injection wells. The first half of the sequence of mappable events occurred along linear trends, but the pattern became more scattered during the later half of the sequence. The lack of seismicity during the pressurized injection and the increased seismicity levels occurring away from injection wells during waterflood production, suggest seismicity is not induced by Mohr-Coulomb failure. 6 refs., 6 figs.

  9. Preliminary Analysis of AVIRIS Data for Tectonostratigraphic Assessment of Northern Guerrero State, Southern Mexico

    NASA Technical Reports Server (NTRS)

    Lang, Harold R.; Cabral-Cano, Enrique

    1996-01-01

    The tectonostratigraphic evolution of the southern margin of the North America Plate in Mexico is still in debate. Recent explanations assert Laramide age (Campanian-Eocene) accretion of far-travelled oceanic terranes. In 1989, we began an effort to bring new data to this debate through field mapping, incorporating Landsat Thematic Mapper and digital elevation data, along a 30 km by 250 km, east-west geologic transect of northern Guerrero State. Covering the region from Huetamo, Michoacan, to Papalutla, Guerrero (between latitude 18-19 deg N and longitude 101-99 deg W), our mapping results show that no stratigraphic incompatibilities suggesting terrane accretion exist in the region. In November 1994, AVIRIS data were acquired along the geologic transect in order to refine our stratigraphic assessment. One objective of this hyperspectral survey was to improve mapping of limestone, dolostone and gypsum-bearing facies of the Morelos Formation which record rudist carbonate platform environments during mid-Cretaceous time.

  10. Preliminary Analysis of AVIRIS Data for Tectonostratigraphic Assessment of Northern Guerrero State, Southern Mexico

    NASA Technical Reports Server (NTRS)

    Lang, Harold R.; Cabral-Cano, Enrique

    1996-01-01

    The tectonostratigraphic evolution of the southern margin of the North America Plate in Mexico is still in debate. Recent explanations assert Laramide age (Campanian-Eocene) accretion of far-travelled oceanic terranes. In 1989, we began an effort to bring new data to this debate through field mapping, incorporating Landsat Thematic Mapper and digital elevation data, along a 30 km by 250 km, east-west geologic transect of northern Guerrero State. Covering the region from Huetamo, Michoacan, to Papalutla, Guerrero (between latitude 18-19 deg N and longitude 101-99 deg W), our mapping results show that no stratigraphic incompatibilities suggesting terrane accretion exist in the region. In November 1994, AVIRIS data were acquired along the geologic transect in order to refine our stratigraphic assessment. One objective of this hyperspectral survey was to improve mapping of limestone, dolostone and gypsum-bearing facies of the Morelos Formation which record rudist carbonate platform environments during mid-Cretaceous time.

  11. Mexico

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of Mexico was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. In areal extent, Mexico is the third largest country on the continent of North America (not counting Greenland, which is a province of Denmark), comprised of almost 2 million square kilometers (756,000 square miles) of land. Home to roughly 100 million people, Mexico is second only to the United States in population, making it the world's largest Spanish-speaking nation. To the north, Mexico shares its border with the United States-a line that runs some 3,100 kilometers (1,900 miles) east to west. About half of this border is defined by the Rio Grande River, which runs southeast to the Gulf of Mexico (partially obscured by clouds in this image) and marks the dividing line between Texas and Mexico. Toward the upper left (northwest) corner of this image is the Baja California peninsula, which provides the western land boundary for the Gulf of California. Toward the northwestern side of the Mexican mainland, you can see the Sierra Madre Occidental Mountains (brownish pixels) running southeast toward Lake Chapala and the city of Guadalajara. About 400 km (250 miles) east and slightly south of Lake Chapala is the capital, Mexico City. Extending northward from Mexico City is the Sierra Madre Oriental Mountains, the irregular line of brownish pixels that seem to frame the western edges of the bright white cumulus clouds in this image. Between these two large mountain ranges is a large, relatively dry highland region. To the south, Mexico shares borders with Guatemala and Belize, both of which are located south of Mexico's Yucatan Peninsula. Image courtesy Reto Stockli, Brian Montgomery, and Robert Simmon, based on data from the MODIS Science Team

  12. Mexico

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of Mexico was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. In areal extent, Mexico is the third largest country on the continent of North America (not counting Greenland, which is a province of Denmark), comprised of almost 2 million square kilometers (756,000 square miles) of land. Home to roughly 100 million people, Mexico is second only to the United States in population, making it the world's largest Spanish-speaking nation. To the north, Mexico shares its border with the United States-a line that runs some 3,100 kilometers (1,900 miles) east to west. About half of this border is defined by the Rio Grande River, which runs southeast to the Gulf of Mexico (partially obscured by clouds in this image) and marks the dividing line between Texas and Mexico. Toward the upper left (northwest) corner of this image is the Baja California peninsula, which provides the western land boundary for the Gulf of California. Toward the northwestern side of the Mexican mainland, you can see the Sierra Madre Occidental Mountains (brownish pixels) running southeast toward Lake Chapala and the city of Guadalajara. About 400 km (250 miles) east and slightly south of Lake Chapala is the capital, Mexico City. Extending northward from Mexico City is the Sierra Madre Oriental Mountains, the irregular line of brownish pixels that seem to frame the western edges of the bright white cumulus clouds in this image. Between these two large mountain ranges is a large, relatively dry highland region. To the south, Mexico shares borders with Guatemala and Belize, both of which are located south of Mexico's Yucatan Peninsula. Image courtesy Reto Stockli, Brian Montgomery, and Robert Simmon, based on data from the MODIS Science Team

  13. Integrating Service Learning into the Study Abroad Program: U.S. Sociology Students in Mexico

    ERIC Educational Resources Information Center

    Wessel, Nancy

    2007-01-01

    The program that is the topic of this case study was an integration of two forms of experiential education: service learning and study abroad. Participants in the program studied sociology and performed social service in Morelia, Michoacan, Mexico. Curriculum and planning issues of both study abroad and service learning are combined in the design…

  14. Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae).

    PubMed

    Burke, Alan F; Rifkind, Jacques; Zolnerowich, Gregory

    2015-01-01

    Four new species of Cymatodera are described from Mexico: Cymatoderatortuosa Burke & Rifkind, sp. n. from Hidalgo and Tamaulipas; Cymatoderaortegae Burke, sp. n. from Colima, Jalisco and Michoacan; Cymatoderagerstmeieri Burke & Rifkind, sp. n. from Chiapas; and Cymatoderamixteca Burke & Rifkind, sp. n. from Puebla and Guerrero. Male genitalia and other characters of taxonomic value are illustrated.

  15. Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae)

    PubMed Central

    Burke, Alan F.; Rifkind, Jacques; Zolnerowich, Gregory

    2015-01-01

    Abstract Four new species of Cymatodera are described from Mexico: Cymatodera tortuosa Burke & Rifkind, sp. n. from Hidalgo and Tamaulipas; Cymatodera ortegae Burke, sp. n. from Colima, Jalisco and Michoacan; Cymatodera gerstmeieri Burke & Rifkind, sp. n. from Chiapas; and Cymatodera mixteca Burke & Rifkind, sp. n. from Puebla and Guerrero. Male genitalia and other characters of taxonomic value are illustrated. PMID:26257571

  16. Mexico.

    PubMed

    1988-02-01

    Focus in this discussion of Mexico is on the following: geography; the people; history; political conditions; the economy; foreign relations; and relations between the US and Mexico. As of July 1987, the population of Mexico numbered 81.9 million with an estimated annual growth rate of 2.09%. 60% of the population is Indian-Spanish (mestizo), 30% American Indian, 9% white, and 1% other. Mexico is the most populous Spanish-speaking country in the world and the 2nd most populous country in Latin America. Education is decentralized and expanded. Mexico's topography ranges from low desert plains and jungle-like coastal strips to high plateaus and rugged mountains. Hernan Cortes conquered Mexico in 1919-21 and founded a Spanish colony that lasted for almost 300 years. Independence from Spain was proclaimed by Father Miguel Hidalgo on September 16, 1810; the republic was established on December 6, 1822. Mexico's constitution of 1917 provides for a federal republic with a separation of powers into independent executive, legislative, and judicial branches of government. Significant political themes of the administration of President Miguel de la Madrid Hurtado, who began his 6-year term in 1982, have been restructuring the economy, liberalizing trade practices, decentralizing government services, and eliminating corruption among public servants. In 1987, estimates put the real growth of the Mexican economy at 1.5%; the gross domestic product (GDP) had shrunk by 3.5% in 1986. Yet, on the positive side, Mexico's international reserves increased to record levels in 1987 (to about $15 billion), and its current account surplus reached more than $3 billion. Mexico has made considerable progress in moving to restructure its economy. It has substantially reduced impediments to international trade and has moved to reduce the number of parastatal firms. 1987 was the 2nd consecutive year in which Mexico recorded triple-digit inflation; inflation reached 158.8%. Other problems include

  17. Hydrologic Modeling of the White Sands Dune Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Bourret, S. M.; Newton, B. T.; Person, M. A.

    2013-12-01

    The shallow groundwater flow system of White Sands dune field, located within the Tularosa Basin of Southern New Mexico, likely stabilizes the base of the largest gypsum dunefield in the world. Water table geometry and elevation play a critical role in controlling dune thickness, spatial extent, and migration rates. The White Sands National Monument (WHSA) is concerned that lowering the water table may lead to increased scour and migration of the dune field, which could be unfavorable to the preservation of the flora and fauna that have adapted to survive there. In response to projected increases in groundwater pumping in the regional Tularosa Basin groundwater system, changes in surface water use, and the threat of climate change, the WHSA is interested in understanding how these changes on a regional scale may impact the shallow dune aquifer. We have collected hydrological, geochemical, and geophysical data in order to identify the sources of recharge that contribute to the shallow dune aquifer and to assess interactions between this water table aquifer and the basin-scale, regional system. Vertical head gradients, temperature, and water quality data strongly suggest that local precipitation is the primary source of recharge to the dune aquifer today. This suggests that the modern dune system is relatively isolated from the deeper regional system. However, geochemical and electrical resistivity data indicates that the deeper basin groundwater system does contribute to the shallow system and suggests that hydrologic conditions have changed on geologic time scales. We have constructed a preliminary cross-sectional hydrologic model to attempt to characterize the interaction of the shallow dune aquifer with the deeper basin groundwater. The model cross-section extends about 80 km across the Tularosa Basin in a NW-SE direction parallel to the primary flow path. We represented 6 km of Precambrian crystalline basement, Paleozoic sedimentary rocks as well as Pleistocene

  18. Acculturation and drinking among people of Mexican descent in Mexico and the United States.

    PubMed

    Caetano, R; Mora, M E

    1988-09-01

    This article studies the relationships between acculturation and drinking and alcohol-related problems among people of Mexican descent in Mexico and the United States. Subjects in the United States were part of a national probability sample of the Hispanic household population 18 years of age and older. Subjects in Mexico were randomly selected from among adult residents of the city of Morelia and an adjoining rural county, Tarimbaro, both in the State of Michoacan. Both samples were interviewed using the same questionnaire. Response rates were 72% in the United States and 92% in Mexico. Results show that Mexican-American men drink more frequently than men in Michoacan, who, as a group, drink infrequently but consume more often five or more drinks at a sitting as compared with Mexican Americans. Mexican-American women have a lower rate of abstention and a higher rate of women who drink at least once a week and who consume five drinks at a sitting at least once a year than do women in Michoacan. Among men, changes in drinking seem to occur soon after coming to the United States--often within 5 years. Among women, drinking patterns are not related to length of residence in the United States. In spite of less drinking, respondents in Michoacan report more alcohol problems than do Mexican Americans.

  19. Observations of Ozone and Aerosols Over Mexico and Gulf of Mexico During INTEX- B/MILAGRO Field Experiment

    NASA Astrophysics Data System (ADS)

    Butler, C. F.; Browell, E. V.; Hair, J. W.; Fenn, M. A.; Notari, A.; Kooi, S. A.; Ismail, S.; Avery, M. A.; Pierce, R. B.

    2007-12-01

    The NASA Langley Research Center's Differential Absorption Lidar (LaRC/DIAL) system has been used to measure ozone and aerosol distributions in many airborne global tropospheric and stratospheric campaigns since 1980. The tropospheric configuration of this system was flown on the NASA DC-8 during the INTEX-B (Phase-I)/MILAGRO (I/M) field experiment, which was conducted from 24 February to 22 March 2006 over Mexico and the Gulf of Mexico. DIAL remote profile measurements were made from near the surface to above the tropopause along the flight track of the DC-8 with a small data void region of 750 m above and below the aircraft. Aerosol scattering ratios were determined at two wavelengths for a gross estimation of the relative size of the observed particles and measurements of aerosol depolarization were made to distinguish nonspherical aerosols, such as dust and some aerosols in aged fire plumes. In situ measurements of ozone from the FASTOZ instrument on the DC-8 were used to constrain the interpolation of the nadir and zenith ozone lidar measurements, which then provided an estimate of the entire tropospheric ozone profile along the flight track. A first order correction for aerosol attenuation was made to the aerosol profiles by using an assumed extinction-to- backscatter ratio to better characterize the attenuation by thick aerosol layers. The DIAL system was used to determine the large-scale variability and context of air masses being sampled in situ on the DC-8 and to direct the in situ sampling strategy in real time. Plumes from biomass burning in southern Mexico were often observed in the free troposphere over the Gulf of Mexico and over eastern Mexico. The Mexico City (MC) pollution plume was readily apparent with high ozone (>100 ppbv), high aerosol scattering (S>20), and enhanced aerosol depolarization (D>10%). The top of the MC pollution extended to a depth of about 2.5 km AGL. Some observations showed the MC plume spilling out over the mountains to

  20. The Seismic Alert System of Mexico (SASMEX): Performance and Evolution

    NASA Astrophysics Data System (ADS)

    Espinosa Aranda, J.

    2013-05-01

    Originally the Seismic Alert System of Mexico (SASMEX) was proposed to integrate the Seismic Alert System of Mexico City (SAS), operating since 1991, with the Seismic Alert System of Oaxaca City (SASO), in services since 2003. And today, after the intense big earthquake activity observed in our world during 2010 and 2011, local governments of Mexico City, Oaxaca Estate, and the Mexican Ministry of the Interior have been promoting the expansion of this technological EEW development. Until 2012 SASMEX better coverage includes 48 new field seismic sensors (FS) deployed over the seismic region of Jalisco, Colima, Michoacan and Puebla, with someone enhancements over Guerrero and Oaxaca, to reach 97 FS. During 2013, 35 new FS has been proposed to SASMEX enhancements covering the Chiapas and Veracruz seismic regions. The SASMEX, with the support of the Mexico Valley Broadcasters Association (ARVM) since 1993, automatically issue Public and Preventive earthquake early warning signals in the Cities of Mexico, Toluca, Acapulco, Chilpancingo, and Oaxaca. The seismic warning range in each case is seated in accordance with local Civil Protection Authorities: Public Alert, if they expect strong earthquake effects, and Preventive Alert one, the effect could be moderated. Now the SASMEX warning time opportunity could be different to the 60 sec. average typically generated when SAS warned earthquake effects coming from Guerrero to Mexico City valley. Mexican EEW issued today reach: 16 Public and 62 Preventive Alert in Mexico City; 25 Public and 19 Preventive Alerts in Oaxaca City; also 14 Public and 4 Preventive Alerts in Acapulco; 14 Public and 5 Preventive Alerts in Chilpancingo. The earthquakes events registered by SASMEX FS until now reach 3448. With the support of private and Federal telecommunications infrastructure like, TELMEX, Federal Electric Commission, and the Mexican Security Ministry, it was developed a redundant communication system with pads to link the different

  1. Mexico.

    PubMed

    1993-01-01

    The background notes on Mexico provide text and recent statistical information on the geography, population, government, economy, and foreign relations, specifically the North American Free Trade Agreement with US. The 1992 population is estimated at 89 million of which 60% are mestizo (Indian-Spanish), 30% are American Indian, 9% are Caucasian, and 1% are other. 90% are Roman Catholic. There are 8 years of compulsory education. Infant mortality is 30/1000 live births. Life expectancy for males is 68 years and 76 years for females. The labor force is comprised of 30% in services, 24% in agriculture and fishing, 19% in manufacturing, 13% in commerce, 7% in construction, 4% in transportation and communication, and .4% in mining. There are 31 states and a federal district. Gross domestic product (GDP) per capita was $3200 in 1991. Military expenditures were .5% of GDP in 1991. The average inflation rate is 19%. Mexico City with 20 million is the largest urban center in the world. In recent years, the economy has been restructured with market oriented reforms; the result has been a growth of GDP of 3.6% in 1991 from 2% in 1987. Dependence on oil exports has decreased. There has been privatization and deregulation of state-owned companies. Subsidies to inefficient companies have been stopped. Tariff rates were reduced. The financial debt has been reduced and turned into a surplus of .8% in 1992. Mexico's foreign debt has been reduced from its high in 1987 of $107 billion. Agricultural reforms have been ongoing for 50 years. Land was redistributed, but standards of living and productivity have improved only slightly. Rural land tenure regulations have been changed, and other economic reforms are expected. Mexico engages in ad hoc international groups and is selective about membership in international organizations.

  2. Ethnological Field Training in the Mezquital Valley, Mexico. Papers from the Ixmiquilpan Field Schools in Cultural Anthropology and Linguistics.

    ERIC Educational Resources Information Center

    Kenny, Michael, Ed.; Bernard, H. Russell, Ed.

    Thirteen papers by graduate students who participated in a 1971 summer field program in Hidalgo, Mexico, are presented. Twelve of the papers are presented in the English language and one is presented in Spanish. Research for seven of the papers was undertaken in established Otomi Indian villages or hamlets. Research for the remaining six papers…

  3. Kinematics and age of Early Tertiary trench parallel volcano-tectonic lineaments in southern Mexico: Tectonic implications

    NASA Astrophysics Data System (ADS)

    Martini, M.; Ferrari, L.; Lopez Martinez, M.; Cerca Martinez, M.; Serrano Duran, L.

    2007-05-01

    We present new geological, structural, and geochronological data that constrain the timing and geometry of Early Tertiary strike slip deformation in southwestern Mexico and its relation with the concurrent magmatic activity. Geologic mapping in Guerrero and Michoacan States documented two regional WNW trending volcano-tectonic lineaments sub parallel to the present trench. The southernmost lineament runs for ~140 km from San Miguel Totolapan area (NW Guerrero) to Sanchiqueo (SE Michoacan), and passes through Ciudad Altamirano. Its southeastern part is marked by the alignment of at least eleven silicic to intermediate major domes as well as by the course of the Balsas River. The northwestern part of the lineament is characterized by ductile left lateral shear zones in Early Tertiary plutonic rocks observed in the Rio Chiquito valley. Domes near Ciudad Altamirano are unaffected by ductile shearing and yielded a ~42 Ma 40Ar/39Ar age, setting a minimum age for this deformation. The northern volcano-tectonic lineament runs for ~190 km between the areas of Huitzuco in northern Guerrero and the southern part of the Tzitzio fold in eastern Michoacan. The Huautla, Tilzapotla, Taxco, La Goleta and Nanchititla silicic centers (all in the range 37-34 Ma) are emplaced along this lineament, which continues to the WNW trough a mafic dike swarm exposed north of Tiquicheo (37-35 Ma) and the Purungueo subvolcanic body (~42 Ma). These rocks, unaffected by ductile shearing, give a minimum age of deformation similar to the southern Totolapan-Sanquicheo lineament. Post ~42 Ma deformation is essentially brittle and is characterized by several left lateral and right lateral transcurrent faults with typical Riedel patterns. Other trench-parallel left lateral shear zones active in pre-Oligocene times were recently reported in western Oaxaca. The recognizing of Early Tertiary trench-parallel and left-lateral ductile shearing in internal areas of southern Mexico suggest a field of widely

  4. Mushroom growing project at the Los Humeros, Mexico geothermal field

    SciTech Connect

    Rangel, M.E.R.

    1998-12-01

    There are several projects of direct (non-electrical) use of geothermal energy in Mexico. Personnel of the Comision Federal de Electricidad (CFE) have experience in various of these projects, like drying of timber and fruits, space heating, food processing, etc. Taking this in consideration, CFE built the Los Humeros mushroom plant using for heat source the geothermal steam from Well H-1. The main purpose of the project was to take advantage of residual geothermal energy in a food production operation and to develop the appropriate technology. In 1992, existing installations were renovated, preparing appropriate areas for pasteurization, inoculation and production. The mushroom Pleurotus ostreatus var. florida and columbinus was used. A year later, CFE proposed the construction of improved facilities for growing edible mushrooms. New materials and equipment, as well as different operation conditions, were proposed on the basis of the experience gained in the initial project. The construction and renovation activities were completed in 1994.

  5. Development of a blocking ELISA for screening antibodies to porcine rubulavirus, La Piedad Michoacan Virus.

    PubMed

    Nordengrahn, A; Svenda, M; Moreno-Lopez, J; Bergvall, A; Hernandez, P; McNeilly, F; Allan, G; Merza, M

    1999-07-01

    A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to porcine rubulavirus (La Piedad Michoacan Virus [LPMV]) in serum samples from pigs. The test, based on a monoclonal antibody against the LPMV hemagglutinin-neuraminidase glycoprotein, had a sensitivity of 99% and a specificity of 97%. The results of this test were in agreement with those obtained by an indirect ELISA and hemagglutination inhibition, indirect immunofluorescence, and virus neutralization tests. The blocking ELISA is considered the most suitable test for routine screening for antibodies against LPMV.

  6. Fern Biology in Mexico - (A Class Field Program)

    ERIC Educational Resources Information Center

    Tryon, Rolla; And Others

    1973-01-01

    Organized field trips in the tropics proved to be an effective way to gather new information about ferns. The areas of study covered were: systematics and ecology, cytology and gametophyte structure, and morphogenesis and physiology. (PS)

  7. Fern Biology in Mexico - (A Class Field Program)

    ERIC Educational Resources Information Center

    Tryon, Rolla; And Others

    1973-01-01

    Organized field trips in the tropics proved to be an effective way to gather new information about ferns. The areas of study covered were: systematics and ecology, cytology and gametophyte structure, and morphogenesis and physiology. (PS)

  8. Field response of Dendroctonus frontalis (Coleoptera: Scolytinae) to synthetic semiochemicals in Chiapas, Mexico.

    PubMed

    Moreno, Benjamín; Macías, Jorge; Sullivan, Brian T; Clarke, Stephen R

    2008-12-01

    Dendroctonus frontalis Zimmermann (Coleoptera: Scolytinae) is the most serious pest of pines (Pinus spp.) in Mexico. Conspecifics are attracted to trees undergoing colonization by the aggregation pheromone frontalin, which is synergized by odors of pine oleoresin released from beetle-damaged host tissue. Synthetic racemic frontalin combined with turpentine has been the operational bait used in traps for monitoring populations of D. frontalis in Mexico as well as the United States. Recently, racemic endo-brevicomin has been reported to be a synergist of the frontalin/turpentine bait and as an important component of the aggregation pheromone for D. frontalis populations in the United States. To determine whether racemic endo-brevicomin also might function as an aggregation synergist for the geographically isolated D. frontalis populations of Central America and Mexico, we performed a field trapping trial in Lagunas de Montebello National Park, Chiapas, Mexico, during July and August 2007. The combination of endo-brevicomin (placed either directly on the trap or 4 m away) plus racemic frontalin and turpentine caught at least 5 times more D. frontalis of both sexes than did turpentine either alone or in combination with either frontalin or endo-brevicomin. The addition of endo-brevicomin to the frontalin/turpentine bait also increased the proportion of females trapped. We conclude that the addition of endo-brevicomin might substantially improve the efficiency of the frontalin/turpentine bait for monitoring of D. frontalis in Central America and Mexico. We discuss factors that reconcile our results with previous studies that reported endo-brevicomin to be an attractant antagonist for populations of D. frontalis in Mexico and Honduras.

  9. Jorullo Volcano, Michoacan, Mexico: the earliest stages of fractionation in calc-alkaline magmas

    SciTech Connect

    Luhr, J.; Carmichael, I.S.E.

    1985-01-01

    Between 1759 and 1774, Jorullo Volcano and four associated cinder cones erupted approximately 2 km/sup 3/ of magma which evolved progressively with time from early ol-hy-normative primitive basalts (Mgnumber=73, 516 ppm Cr, 260 ppm Ni) to late-stage qtz-hy-normative basaltic andesites. All lavas contain <6 vol% phenocrysts of magnesian olivine (fO/sub 90-70/) with Cr-Al-Mg spinel inclusions, and microphenocrysts of plagioclase and augite. Smooth whole-rock major and trace element compositional trends through the suite can be largely modeled by simple crystal fractionation of olivine, augite, plagioclase, and minor spinel. In order for augite and plagioclase to have been near-liquidus phases, the modeled crystal fractionation event must have occurred at lower-crustal to upper-mantle pressures (8-15 Kb). The crystals actually present in the Jorullo lavas, however, formed at low pressures. Compared to modeled abundances, La, Ce, Rb, Sr, Ba, Hf, Th, and Ta are anomalously enriched in the late-stage basaltic andesites and Dy, Yb, and Lu are anomalously depleted. These discrepancies apparently indicate the importance of other magma-chamber processes. Most high-alumina basalts reported in the literature have 18 to 21 wt% Al/sub 2/O/sub 3/, but are too depleted in MgO, Cr, and Ni to be direct mantle products. These high-alumina basalts have probably undergone significant fractionation of olivine, augite, plagioclase, and spinel from primitive parental basalt similar to the early Jorullo magmas. For hydraulic reasons, such primitive basalts are rarely erupted in mature arcs, and may be completely absent from mature stratovolcanoes.

  10. [Taeniasis, amebiasis and other intestinal parasitosis in school age children from Michoacan State, Mexico].

    PubMed

    Lara-Aguilera, R; Aguilar-Bucio, M T; Martínez-Toledo, J L

    1990-03-01

    92.3% schoolchildren aged 6-13 years of a mexican rural village, suspected foci of Taenia solium cysticercosis were screened for intestinal parasites with the main purpose to know the infection rate by taeniasis. An stool sample was collected to schoolchildren of the village and 95.4% of a urban private school as comparative group. Laboratory examinations were performed with the most accurate technics, included microscopies with an ocular micrometer. The general parasitation rate was 4 times higher in the rural village, but the percentages of Taenia spp. infection were 0.6% both of them. Entamoeba histolytica was observed 1.8% and 7.2% in the city and rural village, respectively. All the cases with taeniasis passed T. saginata after treatment with niclosamide. Negative results were obtained with the same chemotherapy in a randomly selected group of 112 schoolchildren which previous stool examination was reported negative. Neither taeniasis were demonstrated in 94 adult persons. These data are suggestive of the great variability on the transmission rates of T. solium cysticercosis in endemic areas and illustrate the faced methodological problems to confirm the diagnosis of taeniasis. By other hand support the hypothesis that estimates of infection rates with E. histolytica have been overdiagnosed in the country. Taeniasis-cysticercosis; schoolchildren; Taenia saginata; amebiasis.

  11. Epidemiological investigation of Taenia solium taeniasis and cysticercosis in a rural village of Michoacan state, Mexico.

    PubMed

    Sarti, E; Schantz, P M; Plancarte, A; Wilson, M; Gutierrez, O I; Aguilera, J; Roberts, J; Flisser, A

    1994-01-01

    We performed a survey for taeniasis and cysticercosis among persons living in a Mexican village where Taenia solium infection in pigs was known to be enzootic. A standardized questionnaire was administered in all 577 households to obtain medical histories and information on demographic and environmental factors and on risk factors associated with transmission of infection. Serum and/or stool specimens were obtained from 1005 volunteers and examined for cysticercosis antibodies and intestinal parasites. Faecal examination of 828 participants revealed infection by Taenia sp. in 2 (0.2%). Three additional cases of taeniasis were detected in individuals who evacuated proglottids after treatment with praziquantel. Of 1005 human serum specimens, 49 (4.9%) were positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a peak in subjects aged 46-55 years (P < 0.05). A history of seizures was significantly associated with seropositivity (P < 0.05); approximately 25% of persons with such histories were seropositive. Histories of headache, dizziness, trembling, blurred vision, and vomiting were also significantly associated with positive immunoblot assays. This study has demonstrated previously undiagnosed morbidity associated with T. solium neurocysticercosis and identified community behavioural and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

  12. 7 CFR 319.56-30 - Hass avocados from Michoacan, Mexico.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... that meets the requirements of paragraph (c)(3) of this section. The Mexican national plant protection... Section 319.56-30 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT... be imported only if the Mexican avocado industry association representing Mexican avocado...

  13. Some Comments on the La Primavera Geothermal Field, Mexico

    SciTech Connect

    A., Bernardo Dominguez; Lippmann, Marcelo J.

    1983-12-15

    The La Primavera geothermal field is located about 20 km west of the city of Guadalajara, Jalisco, in the western part of the Mexican Neovolcanic Axis. Initial results of five deep exploration wells (down to 2000 m depth) were very promising; measured downhole temperatures exceed 300{degrees}C. During production, however, downhole temperatures dropped, and the chemistry of the fluids changed. The analysis of geologic, mineralogic, geochemical, and well completion data indicate that colder fluids flow down the wellbore from shallower aqifers cooling the upper zones of the gothermal reservoir. This problem is attributed to inadequate well completions. Doubts have arisen about continuing the exploration of the field because of the somewhat disappointing drilling results. However, a more thorough analysis of all available data indicates that a good geothermal prospect might exist below 3000 m, and that it could be successfully developed with appropriately located and completed wells.

  14. Apollo 16 prime and backup crewmen during geological field trip in New Mexico

    NASA Image and Video Library

    1971-09-09

    Dr. Lee Silver (pointing foregroung), California Institute of Technology, calls a geological feature near Taos, New Mexico, to the attention of Apollo 16 prime and backup crewmen during a geological field trip. The crewmen, from left to right, are Astronauts Charles M. Duke Jr., lunar module pilot; Fred W. Haise Jr., backup commander; Edgar D. Mitchell, backup Lunar Module pilot; and John W. Young, commander.

  15. Audiomagnetotelluric data, Taos Plateau Volcanic Field, New Mexico

    USGS Publications Warehouse

    Ailes, Chad E.; Rodriguez, Brian D.

    2011-01-01

    The U.S. Geological Survey is conducting a series of multidisciplinary studies of the San Luis Basin as part of the Geologic framework of the Rio Grande Basins project. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys, audiomagnetotelluric surveys, and hydrologic and lithologic data are being used to better understand the aquifers. This report describes a regional east-west audiomagnetotelluric sounding profile acquired in late July 2009 across the Taos Plateau Volcanic Field. No interpretation of the data is included.

  16. Seismotectonics of the Cerro Prieto Geothermal Field, Baja California, Mexico.

    NASA Astrophysics Data System (ADS)

    Rebollar, C. J.; Reyes, L. M.; Quintanar, L.; Arellano, J. F.

    2002-12-01

    We studied the background seismic activity in the Cerro Prieto geothermal field (CPGF) using a network of 21 digital stations. Earthquakes are located below the exploitation area of the CPGF, between 3 and 12 km depth, within the basement. Earthquakes follow roughly a N30°E trend perpendicular to the Cerro Prieto fault. This activity is located on a horst-like structure below the geothermal field and coincides with the zone of maximum subsidence in the CPGF. Two earthquake swarms occurred along the SE-NW strike of the Cerro Prieto fault and in the neighborhood of the Cerro Prieto volcano. Magnitudes range from -0.3 to 2.5. A Vp/Vs=1.91 ratio of the activity below the volcano suggests a water-saturated medium and/or a partial-melt medium. We calculated 76 focal mechanisms of individual events. On June 1 and September 10, 1999, two earthquakes of Mw 5.2 and 5.3 occurred in the basement at depths of 7.4 and 3.8 km below the CPGF. Maximum peak accelerations above the hypocenter ranged from 128.0 to 432.0 cm/s2. Waveform modeling results in a fault geometries given by strike=236°, dip=60°, rake=-58° (normal) and strike=10°, dip=90°, rake=159° (right lateral strike-slip) for the June and September events. Observed triangular source time function of 0.7 seconds and a double source with a total duration of 1.9 seconds for the June and September events were used to calculate the synthetics seismograms. Static stress drops and seismic moments for the June and September events are: Δ\\sigma=82.5 MPa (825 bars), Mo= 7.65x1016 Nm (7.65x1023 dyne-cm) and Δ\\sigma=31.3 MPa (313 bars) and Mo=1.27x1017 Nm (1.27x1024 dyne-cm). These stress drops are typical of continental events rather than stress drops of events originated in spreading centers. We concluded from the focal mechanisms of the background seismicity and June and September 1999 events, that a complex stress environment exits in the CPGF due to the continual thinning of the crust in the Cerro Prieto basin.

  17. Field Studies of Geothermal Reservoirs Rio Grande Rift, New Mexico

    SciTech Connect

    James C Witcher

    2002-07-30

    The Rio Grande rift provides an excellent field laboratory to study the nature of geothermal systems in an extensional environment. Much of the geologic complexity that is found in the Basin and Range is absent because the rift is located on cratonic crust with a thin and well-characterized Phanerozoic stratigraphy and tectonic history. On the other hand, the Neogene thermo-tectonic history of the rift has many parallels with the Basin and Range to the west. The geology of the southern Rio Grande rift is among the best characterized of any rift system in the world. Also, most geologic maps for the region are rather unique in that detailed analyses of Quaternary stratigraphic and surficial unit are added in concert with the details of bedrock geology. Pleistocene to Holocene entrenchment of the Rio Grande and tributaries unroofs the alteration signatures and permeability attributes of paleo outflow plumes and upflow zones, associated with present-day, but hidden or ''blind,'' hydrothermal systems at Rincon and San Diego Mountain.

  18. New Mexico Geochronology Research Laboratory: Zuni-Bandera volcanic field road log

    SciTech Connect

    Laughlin, A.W.; Charles, R.; Reid, K.; White, C.

    1993-04-01

    This field conference was designed to assemble a group of Quaternary researchers to examine the possibility of using the Zuni-Bandera volcanic field in western New Mexico as a test area for evaluating and calibrating various Quaternary dating techniques. The Zuni-Bandera volcanic-field is comprised of a large number of basaltic lava flows ranging in age from about 700 to 3 ka. Older basalts are present in the Mount Taylor volcanic field to the north. Geologic mapping has been completed for a large portion of the Zuni-Bandera volcanic field and a number of geochronological investigations have been initiated in the area. While amending this conference, please consider how you might bring your expertise and capabilities to bear on solving the many problem in Quaternary geochronology.

  19. New Mexico Geochronology Research Laboratory: Zuni-Bandera volcanic field road log

    SciTech Connect

    Laughlin, A.W.; Charles, R.; Reid, K.; White, C.

    1993-01-01

    This field conference was designed to assemble a group of Quaternary researchers to examine the possibility of using the Zuni-Bandera volcanic field in western New Mexico as a test area for evaluating and calibrating various Quaternary dating techniques. The Zuni-Bandera volcanic-field is comprised of a large number of basaltic lava flows ranging in age from about 700 to 3 ka. Older basalts are present in the Mount Taylor volcanic field to the north. Geologic mapping has been completed for a large portion of the Zuni-Bandera volcanic field and a number of geochronological investigations have been initiated in the area. While amending this conference, please consider how you might bring your expertise and capabilities to bear on solving the many problem in Quaternary geochronology.

  20. Volume 4: Characterization of representative reservoirs -- Gulf of Mexico field, U-8 reservoir

    SciTech Connect

    Koperna, G.J. Jr.; Johnson, H.R.; Salamy, S.P.; Reeves, T.K.; Sawyer, W.K.; Kimbrell, W.C.; Schenewerk, P.A.

    1998-07-01

    A reservoir study was performed using a publicly available black oil simulator to history match and predict the performance of a Gulf of Mexico reservoir. The first objective of this simulation study was to validate the Black Oil Applied Simulation Tool version three for personal computers (BOAST3-PC) model to ensure the integrity of the simulation runs. Once validation was completed, a field history match for the Gulf of Mexico U-8 oil reservoir was attempted. A verbal agreement was reached with the operator of this reservoir to blindcode the name and location of the reservoir. In return, the operator supplied data and assistance in regards to the technical aspects of the research. On the basis of the best history match, different secondary recovery techniques were simulated as a predictive study for enhancing the reservoir productivity.

  1. Excitation of high-frequency surface waves with long duration in the Valley of Mexico

    NASA Astrophysics Data System (ADS)

    Iida, Masahiro

    1999-04-01

    During the 1985 Michoacan earthquake (Ms = 8.1), large-amplitude seismograms with extremely long duration were recorded in the lake bed zone of Mexico City. We interpret high-frequency seismic wave fields in the three geotechnical zones (the hill, the transition, and the lake bed zones) in the Valley of Mexico on the basis of a systematic analysis for borehole strong motion recordings. We make identification of wave types for real seismograms. First, amplitude ratios between surface and underground seismograms indicate that predominant periods of the surface seismograms are largely controlled by the wave field incident into surficial layers in the Valley of Mexico. We interpret recorded surface waves as fundamental-mode Love waves excited in the Mexican Volcanic Belt by calculating theoretical amplification for different-scale structures. Second, according to a cross-correlation analysis, the hill and transition seismograms are mostly surface waves. In the lake bed zone, while early portions are noisy body waves, late portions are mostly surface waves. Third, using two kinds of surface arrays with different station intervals, we investigate high-frequency surface-wave propagation in the lake bed zone. The wave propagation is very complicated, depending upon the time section and the frequency band. Finally, on the basis of a statistical time series model with an information criterion, we separate S- and surface-wave portions from lake bed seismograms. Surface waves are dominant and are recognized even in the early time section. Thus high-frequency surface waves with long duration in the Valley of Mexico are excited by the Mexican Volcanic Belt.

  2. Treatment of cutaneous leishmaniasis with localized current field (radio frequency) in Tabasco, Mexico.

    PubMed

    Velasco-Castrejon, O; Walton, B C; Rivas-Sanchez, B; Garcia, M F; Lazaro, G J; Hobart, O; Roldan, S; Floriani-Verdugo, J; Munguia-Saldana, A; Berzaluce, R

    1997-09-01

    In Mexico cutaneous leishmaniasis (CL) occurs in 17 of 32 States, and is a serious public health problem. This is a report of treatment of CL patients in the State of Tabasco, Mexico with a localized current field-radio frequency (LCF-RF) device to generate precisely controlled heat as an alternative to prohibitively expensive drug treatment. It was not a controlled clinical trial, but rather an evaluation of the feasibility of this form of treatment for all CL patients encountered in the endemic area. A total of 201 previously diagnosed patients with CL caused by Leishmania mexicana were treated with a portable Thermosurgery LCF-RF generator powered by rechargeable batteries. The ages of the patients ranged from two to 75 years; the sex distribution was 63% males and 37% females. A single device was used in five different municipalities. Lesions were first anesthetized with 1% lidocaine HCl and moistened with normal saline solution. Treatment consisted of a single application that produced 50 degrees C for 30 sec. After four weeks, 122 patients were available for evaluation, of which 95% were totally cured; (even those involving ear cartilage, which respond poorly to antimonials). At eight weeks post-treatment, 191 patients were evaluated, with a total cure rate of 90%. This form of treatment proved to be effective and convenient for use in primary health care facilities in Mexico and has many advantages over traditional forms of therapy.

  3. Uncertainties in SOA simulations due to meteorological uncertainties in Mexico City during MILAGRO-2006 field campaign

    NASA Astrophysics Data System (ADS)

    Bei, N.; Li, G.; Molina, L. T.

    2013-05-01

    The purpose of the present study is to investigate the uncertainties in simulating secondary organic aerosol (SOA) in Mexico City metropolitan area (MCMA) due to meteorological initial uncertainties using the WRF-CHEM model through ensemble simulations. The simulated periods (24 and 29 March 2006) represent two typical meteorological episodes ("Convection-South" and "Convection-North", respectively) in the Mexico City basin during the MILAGRO-2006 field campaign. The organic aerosols are simulated using a non-traditional SOA model including the volatility basis-set modeling method and the contributions from glyoxal and methylglyoxal. Model results demonstrate that uncertainties in meteorological initial conditions have significant impacts on SOA simulations, including the peak time concentrations, the horizontal distributions, and the temporal variations. The ensemble spread of the simulated peak SOA at T0 can reach up to 4.0 μg m-3 during the daytime, which is around 35% of the ensemble mean. Both the basin wide wind speed and the convergence area affect the magnitude and the location of the simulated SOA concentrations inside the Mexico City basin. The wind speed, especially during the previous midnight and the following early morning, influences the magnitude of the peak SOA concentration through ventilation. The surface horizontal convergence zone generally determines the area with high SOA concentrations. The magnitude of the ensemble spreads may vary with different meteorological episodes but the ratio of the ensemble spread to mean does not change significantly.

  4. Uncertainties in SOA simulations due to meteorological uncertainties in Mexico City during MILAGRO-2006 field campaign

    NASA Astrophysics Data System (ADS)

    Bei, N.; Li, G.; Molina, L. T.

    2012-12-01

    The purpose of the present study is to investigate the uncertainties in simulating secondary organic aerosol (SOA) in Mexico City metropolitan area (MCMA) due to meteorological initial uncertainties using the WRF-CHEM model through ensemble simulations. The simulated periods (24 and 29 March 2006) represent two typical meteorological episodes ("Convection-South" and "Convection-North", respectively) in the Mexico City basin during the MILAGRO-2006 field campaign. The organic aerosols are simulated using a non-traditional SOA model including the volatility basis-set modeling method and the contributions from glyoxal and methylglyoxal. Model results demonstrate that uncertainties in meteorological initial conditions have significant impacts on SOA simulations, including the peak time concentrations, the horizontal distributions, and the temporal variations. The ensemble spread of the simulated peak SOA at T0 can reach up to 4.0 μg m-3 during the daytime, which is around 35% of the ensemble mean. Both the basin wide wind speed and the convergence area affect the magnitude and the location of the simulated SOA concentrations inside the Mexico City basin. The wind speed, especially during the previous midnight and the following early morning, influences the magnitude of the peak SOA concentration through ventilation. The surface horizontal convergence zone generally determines the area with high SOA concentrations. The magnitude of the ensemble spreads may vary with different meteorological episodes but the ratio of the ensemble spread to mean does not change significantly.

  5. Uncertainties in SOA simulations due to meteorological uncertainties in Mexico City during MILAGRO-2006 field campaign

    NASA Astrophysics Data System (ADS)

    Bei, N.; Li, G.; Molina, L. T.

    2012-07-01

    The purpose of the present study is to investigate the uncertainties in simulating secondary organic aerosol (SOA) in Mexico City metropolitan area (MCMA) due to meteorological initial uncertainties using the WRF-CHEM model through ensemble simulations. The simulated periods (24 and 29 March 2006) represent two typical meteorological episodes ("Convection-South" and "Convection-North", respectively) in the Mexico City basin during the MILAGRO-2006 field campaign. The organic aerosols are simulated using a non-traditional SOA model including the volatility basis-set modeling method and the contributions from glyoxal and methylglyoxal. Model results demonstrate that uncertainties in meteorological initial conditions have significant impacts on SOA simulations, including the peak time concentrations, the horizontal distributions, and the temporal variations. The ensemble spread of the simulated peak SOA at T0 can reach up to 4.0 µg m-3 during the daytime, which is around 35% of the ensemble mean. Both the basin wide wind speed and the convergence area affect the magnitude and the location of the simulated SOA concentrations inside the Mexico City basin. The wind speed, especially during the previous midnight and the following early morning, influences the magnitude of the peak SOA concentration through ventilation. The surface horizontal convergence zone generally determines the area with high SOA concentrations. The magnitude of the ensemble spreads may vary with different meteorological episodes but has same significance compared to the ensemble mean.

  6. Mexico City basin wind circulation during the MCMA-2003 field campaign

    NASA Astrophysics Data System (ADS)

    de Foy, B.; Caetano, E.; Magaña, V.; Zitácuaro, A.; Cárdenas, B.; Retama, A.; Ramos, R.; Molina, L. T.; Molina, M. J.

    2005-05-01

    MCMA-2003 was a major field campaign investigating the atmospheric chemistry of the Mexico City Metropolitan Area (MCMA) in April of 2003. This paper describes the wind circulation patterns during the campaign both within the Mexico City basin and on the regional scale. ''Time roses'' are introduced to concisely analyze the diurnal wind patterns. Three episode types were identified that explain the conditions encountered: ''O3-South'', ''Cold Surge'' and ''O3-North''. These can be diagnosed from a combination of synoptic and basin observations based on whether the day was predominantly cloudy, or whether the O3 peak was in the north or south of the basin. O3-South days have weak synoptic forcing due to an anti-cyclone over the eastern Pacific. Strong solar heating leads to northerly flows in the basin and an evening shift due to a gap flow from the south-east. Peak ozone concentrations are in the convergence zone in the south of the city. Cold Surge days are associated with ''El Norte'' events, with strong surface northerlies bringing cold moist air and rain. Stable conditions lead to high concentrations of primary pollutants and peak ozone in the city center. O3-North days occur when the sub-tropical jet is closer to Mexico City. With strong westerlies aloft, the circulation pattern is the same as O3-South days except for a wind shift in the mid-afternoon leading to ozone peaks in the north of the city. This classification is proposed as a means of understanding pollutant transport in the Mexico City basin and as a basis for future meteorological and chemical analysis. Furthermore, model evaluation and design of policy recommendations will need to take into account the three episode types.

  7. Mexico City basin wind circulation during the MCMA-2003 field campaign

    NASA Astrophysics Data System (ADS)

    de Foy, B.; Caetano, E.; Magaña, V.; Zitácuaro, A.; Cárdenas, B.; Retama, A.; Ramos, R.; Molina, L. T.; Molina, M. J.

    2005-08-01

    MCMA-2003 was a major field campaign investigating the atmospheric chemistry of the Mexico City Metropolitan Area (MCMA) in April of 2003. This paper describes the wind circulation patterns during the campaign both within the Mexico City basin and on the regional scale. ''Time roses'' are introduced to concisely analyze the diurnal wind patterns. Three episode types were identified that explain the conditions encountered: ''O3-South'', ''Cold Surge'' and ''O3-North''. These can be diagnosed from a combination of synoptic and basin observations based on whether the day was predominantly cloudy, or whether the O3 peak was in the north or south of the basin. O3-South days have weak synoptic forcing due to an anti-cyclone over the eastern Pacific. Strong solar heating leads to northerly flows in the basin and an evening shift due to a gap flow from the south-east. Peak ozone concentrations are in the convergence zone in the south of the city. Cold Surge days are associated with ''El Norte'' events, with strong surface northerlies bringing cold moist air and rain. Stable conditions lead to high concentrations of primary pollutants and peak ozone in the city center. O3-North days occur when the sub-tropical jet is closer to Mexico City. With strong westerlies aloft, the circulation pattern is the same as O3-South days except for a wind shift in the mid-afternoon leading to ozone peaks in the north of the city. This classification is proposed as a means of understanding pollutant transport in the Mexico City basin and as a basis for future meteorological and chemical analysis. Furthermore, model evaluation and design of policy recommendations will need to take into account the three episode types.

  8. Direct use of the geothermal energy at Los Azufres geothermal field, Mexico

    SciTech Connect

    Sanchez-Velasco, E.; Casimiro-Espinoza, E.

    1995-12-31

    The main object of Comision Federal de Electricidad (CFE`s) Geothermal Field at Los Azufres, is to generate geothermal electricity; however with the new politics in Mexico, CFE has designed a pilot project in order to profit from the geothermal residual energy and to attract national or foreign investors and convince them that direct use of geothermal energy is an attractive feasible and economical project. The object of this paper is to present the CFE experiences in different pilot projects applied to direct uses of geothermal energy.

  9. Extending field life in offshore Gulf of Mexico using 3-D seismic survey

    SciTech Connect

    Bulling, T.P.; Olsen, R.S. )

    1990-05-01

    Discovered by ARCO in 1967, the High Island 24L field (lower Miocene) is located in the Texas state waters of the Gulf of Mexico. By 1986, the field had produced 320 billion ft{sup 3} of gas and 3.0 million bbl of oil. An engineering field study completed in 1986 showed the field was declining and would be unprofitable within 3 yr. Study of reservoir maps revealed three basin problems: volumetric reserve calculations were less than reserves produced, hydrocarbon-water contacts were inconsistent between wells thought to be in communication, and ultimate recoveries could not be accurately calculated. Attempts to remap the field with the existing two-dimensional seismic data base and well data proved unsuccessful. In 1986, a three-dimensional seismic survey was acquired in an effort to evaluate the true present worth and potential of the field. Remapping of 30 reservoir horizons began in 1987. The integration of detailed well log correlations tied to the dense grid of quality three dimensional seismic data improved the reservoir maps. These maps helped resolve engineering problems by defining the configuration of the reservoirs more accurately. Reservoir maps now closely match volumetrics, fluid contacts within reservoir units are consistent, and a better definition of extension well opportunities exists. The authors study resulted in six additional wells. These wells along with engineering modifications and operations cost containment resulted in the extension of the economic life of the High Island 24-L field by at least 8 yr.

  10. Chemical Variations in the Rocks of La Primavera Geothermal Field (Mexico) Related with Hydrothermal Alteration

    SciTech Connect

    Prol-Ledesma, R.M.; Hernandez-Lombardini, S.I.; Lozano-Santa Cruz, R.

    1995-01-01

    The origin and fate of the components dissolved in the geothermal fluids are of great importance in the study of epithermal deposits, and in the environmental considerations for exploitation of geothermal fields. The chemical study of La Primavera geothermal field in Mexico has environmental importance due to the high arsenic concentration observed in the thermal water and the possible contamination of aquifers in the area. The variations in the chemistry of all altered samples with respect to unaltered samples indicates depletion of manganese, and the alkalis; and enrichment in iron and magnesium. Most samples show an enrichment in aluminum and titanium, and depletion in silica and calcium. Trace elements follow different trends at various depths: shallow depths are more favorable for deposition of the analyzed trace elements than the surface or the deep part of the reservoir.

  11. Field Procedures Manual: Shady Rest, California, and Sulphur Springs, New Mexico

    SciTech Connect

    Goff, S.

    1988-12-01

    This Field Procedures Manual is the comprehensive operations guide to be used to curate samples obtained from the Shady Rest site at Mammoth, California, and the Sulphur Springs site at Valles caldera, New Mexico (VC-2A). These sites are diamond drilling projects in small-diameter holes that will produce continuous core. Fluid samples will also be of primary importance at both of these sites. Detailed core and fluid handling procedures are therefore the major focus of this manual. The manual provides a comprehensive operations guide for the well-site geoscientists working at the Department of Energy/Office of Basic Energy Science (DOE/OBES) Continental Scientific Drilling Program (CSDP)/Thermal Regimes drill sites. These procedures modify and improve those in previous DOE/OBES field manuals. 1 ref., 7 figs.

  12. Heat Sweep Analysis of Thermal Breakthrough at Los Humeros and La Primavera Fields, Mexico

    SciTech Connect

    Kruger, P.; Lam, S.; Molinar, R.; Aragon, A.

    1987-01-20

    Early evaluation of the potential for geothermal breakthrough of reinjected fluids in newly developed geothermal fields can be obtained with the SGP one-dimensional heat sweep model. The model was used to estimate fluid cooldown from wells selected for the first wellhead generating units to be installed at the Los Humeros and La Primavera geothermal fields in Mexico, based on staff-compiled geometric and geologic data, thermal properties of the reservoir rock, and expected production conditions. Geometric considerations were evaluated with respect to known and postulated fault zones and return flow angle of the reinjected fluid. The results show the range of parameter values that affect the rate of thermal breakthrough to an abandonment temperature of 170 ºC corresponding to the minimum inlet pressure to the CFE 5-MW wellhead generator units. 9 figs., 4 tabs., 11 refs.

  13. The origin of bajaites from the San Borja Volcanic Field in Baja California Norte, Mexico

    NASA Astrophysics Data System (ADS)

    Bibbins, M.; Castillo, P.; Negrete-Aranda, R.; Canon-Tapia, E.; Alva-Valdivia, L. M.; Garcia-Amador, B. I.

    2014-12-01

    Baja California is a peninsula in western Mexico that was formed through a dynamic tectonic history of convergence, rifting and strike slip motion. At approximately 13 Ma, subduction along the northwestern coast of Mexico stopped, subsequently the Gulf of California opened and strike slip faults formed parallel to the ancient trench. After subduction ended, arc-related magmatism continued as the Baja peninsula was forming until about 2 Ma. The lavas erupting in the peninsula have variable compositions including calc-alkalic and tholeiitic arc basalts and bajaites. The term bajaite is a collective term for the high magnesian andesites and basaltic andesites in Baja California that have adakitic characteristics. Adakites, on the other hand, are arc lavas characterized by high silica content and Sr/Y and La/Yb ratios; these are generally believed to have formed through melting of subducted basaltic crust. The origin of bajaite is controversial. It has been proposed as product of melting of either subducted basaltic crust primarily because of its adakitic characteristics (Saunders et al, 1987) or metasomatized mantle wedge because of its arc lava-like geochemical features (Castillo, 2008); it has also been proposed as a mixture of differentiated and mafic arc lavas (Streck et al, 2007). The composition of bajaite is similar to that of the bulk continental crust and, thus, its true origin can shed light on the mechanism for continental growth. In this study, we use geochemical techniques to resolve some of the controversies surrounding the origin of bajaite. We analyze the petrographic, major element, trace element, and Sr-Nd-Pb isotopic compositions of bajaites from the San Borja Volcanic Field in Baja California Norte, Mexico to better constrain their petrogenetic history and origin.

  14. Digital Preservation of Ancient Maya Cave Architecture: Recent Field Efforts in Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Rissolo, D.; Lo, E.; Hess, M. R.; Meyer, D. E.; Amador, F. E.

    2017-08-01

    The presence of ancient Maya shrines in caves serves as unequivocal evidence for the ritual appropriation of these subterranean spaces and their significance with respect to Maya religious practice. Detailed study of the miniature masonry temples and altar features in the caves of Quintana Roo, Mexico reveals a strong stylistic and likely functional correspondence between these structures and their terrestrial counterparts at Postclassic sites. The Proyecto Arquitectura Subterranea de Quintana Roo (coordinated by the Center of Interdisciplinary Science for Art, Architecture, and Archaeology, or CISA3, at the University of California, San Diego and in collaboration with the Instituto Nacional de Antropologia e Historia in Mexico) is conducting a survey and program of digital documentation of both the pristine and impacted cave shrines of the region. Once an area is developed and populated, and access is opened to caves containing ancient architectural features, they are soon vandalized - often resulting in the complete obliteration of these rare miniature buildings and their diagnostic architectural elements. This emergent situation necessitates the use of rapid reality-capture tools; however, the physical challenges of working in caves requires researchers of adapt increasingly common architectural documentation methodologies to more adverse field conditions.

  15. Geology and K-Ar dating of the Tuxtla Volcanic Field, Veracruz, Mexico

    NASA Astrophysics Data System (ADS)

    Nelson, Stephen A.; Gonzalez-Caver, Erika

    1992-12-01

    The Tuxtla Volcanic Field (TVF) is located on the coast of the Gulf of Mexico in the southern part of the state of Veracruz, Mexico. Volcanism began about 7 my ago, in the Late Miocene, and continued to recent times with historical eruptions in ad 1664 and 1793. The oldest rocks occur as highly eroded remnants of lava flows in the area surrounding the historically active cone of San Martín Tuxtla. Between about 3 and 1 my ago, four large composite volcanoes were built in the eastern part of the area. Rocks from these structures are hydrothermally altered and covered with lateritic soils, and their northern slopes show extensive erosional dissection that has widened preexisting craters to form erosional calderas. The eastern volcanoes are composed of alkali basalts, hawaiites, mugearites, and benmoreites, with less common calc-alkaline basaltic andesites and andesites. In the western part of the area, San Martín Tuxtla Volcano and its over 250 satellite cinder cones and maars produced about 120 km3 of lava over the last 0.8 my. A ridge of flank cinder cones blocked drainage to the north to form Laguna Catemaco. Lavas erupted from San Martín and its flank vents are restricted to compositions between basanite and alkali basalt. The alignment of major volcanoes and flank vents along a N55°W trend suggests an extensional stress field in the crust with a minimum compressional stress orientation of N35° E. In total, about 800 km3 of lava has been erupted in the TVF in the last 7 my. This gives a magma output rate of about 0.1 km3/1000 year, a value smaller than most composite cones, but similar to cinder cone fields that occur in central Mexico. Individual eruptions over the last 5000 years had volumes on the order of 0.1km3, with average recurrence intervals of 600 years. The alkaline compositions of the TVF lavas contrast markedly with the calc-alkaline compositions erupted in the subduction-related Mexican Volcanic Belt to the west, leading previous workers to

  16. Development of spatially diverse and complex dune-field patterns: Gran Desierto Dune Field, Sonora, Mexico

    USGS Publications Warehouse

    Beveridge, C.; Kocurek, G.; Ewing, R.C.; Lancaster, N.; Morthekai, P.; Singhvi, A.K.; Mahan, S.A.

    2006-01-01

    The pattern of dunes within the Gran Desierto of Sonora, Mexico, is both spatially diverse and complex. Identification of the pattern components from remote-sensing images, combined with statistical analysis of their measured parameters demonstrate that the composite pattern consists of separate populations of simple dune patterns. Age-bracketing by optically stimulated luminescence (OSL) indicates that the simple patterns represent relatively short-lived aeolian constructional events since ???25 ka. The simple dune patterns consist of: (i) late Pleistocene relict linear dunes; (ii) degraded crescentic dunes formed at ???12 ka; (iii) early Holocene western crescentic dunes; (iv) eastern crescentic dunes emplaced at ???7 ka; and (v) star dunes formed during the last 3 ka. Recognition of the simple patterns and their ages allows for the geomorphic backstripping of the composite pattern. Palaeowind reconstructions, based upon the rule of gross bedform-normal transport, are largely in agreement with regional proxy data. The sediment state over time for the Gran Desierto is one in which the sediment supply for aeolian constructional events is derived from previously stored sediment (Ancestral Colorado River sediment), and contemporaneous influx from the lower Colorado River valley and coastal influx from the Bahia del Adair inlet. Aeolian constructional events are triggered by climatic shifts to greater aridity, changes in the wind regime, and the development of a sediment supply. The rate of geomorphic change within the Gran Desierto is significantly greater than the rate of subsidence and burial of the accumulation surface upon which it rests. ?? 2006 The Authors. Journal compilation 2006 International Association of Sedimentologists.

  17. Hydrothermal characteristics of the well A-29 at the Los Azufres geothermal field, Mexico

    SciTech Connect

    Viggiano-Guerra, J.C.; Gutierrez-Negrin, L.C.A.

    1995-12-31

    Three distinct hydrothermal zones can be identified in the well A-29, located at the northeastern border of the Los Azufres, Mexico, geothermal field. They are the zeolite, epidote and amphibole-gamet zones. High temperatures (over 300{degrees}C) were measured, but the well did not produce mass flow. This can be explained by a self-sealing process as a result of three trends recognized in the evolution of geothermal fluids: boiling, boiling and gas losses, and dilution. A certain cooling of at least 25{degrees}C seems to be happening in the well, especially in the epidote zone and in the upper portions of the amphibole-gamet zone.

  18. Porosity of coastal deltaic sandstones, Cerro Prieto geothermal field, Baja California, Mexico

    SciTech Connect

    Vonder Haar, S.P.

    1984-04-01

    Core porosity values for sandstones and density log-derived porosities for sandstone-siltstone-shale sequences indicate a range from less than 1% to 40% at the Cerro Prieto geothermal field, Baja California, Mexico. Mean porosity values indicate that a general trend of decreasing porosities with increasing depth from 35% at 600 m to 10% at 2300 m is complicated by the 15 to 30% porosities in the 350/sup 0/C hot water zone at about 2700 m depth. Scanning electron microscopy documents secondary dissolution porosity, mineral overgrowths, and abundant clay minerals. Core permeability ranges from 0.1 to 1000 millidarcies for the more than 50 cores studied. The porosity variability indicates that geothermal systems provide an ideal setting for testing concepts of dissolution porosity and increased secondary dissolution permeability that could be useful for nuclear waste storage as well as petroleum reservoir engineering.

  19. Mercury in freshwater fish and clams from the Cerro Prieto geothermal field of Baja California, Mexico

    SciTech Connect

    Gutierrez-Galindo, E.A.; Munoz, G.F.; Flores, A.A.

    1988-08-01

    Several reports have expressed concern about the potential toxicity hazards and environmental contamination of mercury emissions from geothermal fields in Hawaii, New Zealand, Iceland, California and Mexico. Inorganic mercury discharged from the sources may accumulate in the sediments of rivers or lakes and, after microbiological methylation may become concentrated in the edible tissue of fish. This study involves assessment of geothermal mercury pollution arising from Cerro Prieto. For this purpose the fish Tilapia mossambica and the clam Corbicula fluminea were collected from the freshwater courses of the Mexicali Valley. Reports indicated that in 1982, 13 t of T. mossambica were destinated for human consumption. A further aim was to provide base line data and information relevant to the level of mercury contamination for the Mexicali Valley.

  20. Geophysical interpretation of the Caribbean plate and Gulf of Mexico from reprocessed potential field data

    NASA Astrophysics Data System (ADS)

    Garcia-Reyes, A.; Dyment, J.; Thebault, E.

    2016-12-01

    Despite of the Caribbean plate and Gulf of Mexico have been widely explored from the last 60 years, there is still no consensus about its nature and age of formation. The imaging of the acoustic basement which can help to better understand the composition of the upper crust, is dependent on seismic reflection and exploratory wells but both of them lack of sufficient penetration. Regarding the magnetic anomalies and possible contribution to decipher the age of the Caribbean seafloor, some authors have reported the lack of an identifiable pattern over the Caribbean Plate (Duncan and Hargraves, 1984, Pindell et al. many publications). Marine tracks widely spaced or with very short coverage, and low amplitude magnetic anomalies constitute a limitation in terms of mapping and interpretation. In this work we present a geophysical interpretation from recently reprocessed marine magnetic data (Garcia et al., 2015), satellite geomagnetic models, and new free-air gravity anomaly derived from altimetry (Sandwell et al., 2014), which is useful to better understand the structure and age of the seafloor and constrain its nature and formation. A marine magnetic anomaly map of the Caribbean region and the Gulf of Mexico to 0.18 degree spatial resolution is showed as resulting from a dedicated processing of the NGDC marine magnetic measurements over the Caribbean region, applied over 516 surveys that were acquired between epochs 1958 and 2012. The corrections applied include the main internal field using a CM4 model for epochs ranging between 1960 and 2002.5 and the IGRF-11 model outside the time range of the CM4 model, removal of outliers, correction by magnetic heading effect, analysis and improvement of the internal and external cross-overs and frequency analysis and separation. This processing allows us to integrate and to interpret the results along with the potential field data mentioned above and open the discussion about the meaning of the magnetic and gravity signatures of

  1. Definition and origin of the dune-field pattern at White Sands, New Mexico

    NASA Astrophysics Data System (ADS)

    Baitis, Elke; Kocurek, Gary; Smith, Virginia; Mohrig, David; Ewing, Ryan C.; Peyret, A.-P. B.

    2014-12-01

    A LiDAR-derived digital elevation model (DEM) of a representative portion of the White Sands Dune Field, New Mexico, allows for characterization of an unprecedented range of dune-field parameters and serves as a basis for pattern analysis. Dune-field parameters were measured and statistically analyzed for populations of dunes selected at random and occurring along transects. Populations sampled by these two different methods are comparable, but highlight the sensitivity of transect placement in a dune field that has pattern heterogeneity. Based upon coefficients of variation, pattern emerges at White Sands primarily because of a strong fabric of crestline orientation, and secondarily because of the regularity of spacing between dunes of similar shape as defined by sinuosity, height and length. Linear regression of dune parameters shows that dune geometric relationships vary primarily with crestline length, but there is little correlation between other parameters, including dune spacing and height. This result highlights the sensitivity of identifying topographic heterogeneity in a LiDAR-derived DEM, given that mean ratios conform to global averages. Stripping off the dunes in Matlab shows a terraced surface, which is interpreted to represent paleo-shorelines formed during relative still stands in the overall retreat of Lake Otero. Elevated bands of higher, more closely spaced dunes occur just leeward of the paleo-shorelines. A revised model for the White Sands Dune Field consists of the basinward progradation of successive dune-field segments. Each segment is associated with a paleo-shoreline, and consists of an upwind dune ridge, represented by the elevated bands, and a leeward dune field.

  2. Interaction of salt tectonics, slumping and channeling: Mid-Pliocene reservoir system, Pompano Field, Gulf of Mexico

    SciTech Connect

    Blankenship, C.L.; Stauber, D.A.; Epps, D.S. )

    1996-01-01

    Newly reprocessed 3-D seismic, converted to Acoustic Impedance, shows the detailed stratigraphy of the mid-Pliocene, upper slope reservoir system of the Pompano Field. This improved data allows us to view the internal slumping and channeling in an interval which was previously poorly imaged. Pompano is located in the Gulf of Mexico at the boundary of Mississippi Canyon and Viosca Knoll.

  3. Interaction of salt tectonics, slumping and channeling: Mid-Pliocene reservoir system, Pompano Field, Gulf of Mexico

    SciTech Connect

    Blankenship, C.L.; Stauber, D.A.; Epps, D.S.

    1996-12-31

    Newly reprocessed 3-D seismic, converted to Acoustic Impedance, shows the detailed stratigraphy of the mid-Pliocene, upper slope reservoir system of the Pompano Field. This improved data allows us to view the internal slumping and channeling in an interval which was previously poorly imaged. Pompano is located in the Gulf of Mexico at the boundary of Mississippi Canyon and Viosca Knoll.

  4. Assessment of remaining recoverable oil in selected major oil fields of the Permian Basin, Texas and New Mexico

    USGS Publications Warehouse

    Tennyson, Marilyn E.; Cook, Troy A.; Charpentier, Ronald R.; Gautier, Donald L.; Klett, Timothy R.; Verma, Mahendra K.; Ryder, Robert T.; Attanasi, E.D.; Freeman, P.A.; Le, Phoung A.

    2012-01-01

    The U.S. Geological Survey (USGS) recently completed an estimate of technically recoverable, conventional oil in selected oil fields in the Permian Basin in west Texas and southeastern New Mexico. The mean total volume of potential additional oil resources that might be added using improved oil-recovery technologies was estimated to be about 2.7 billion barrels of oil.

  5. Adaptive Management and Planning Models for Cultural Resources in Oil and Gas Fields in New Mexico and Wyoming

    SciTech Connect

    Eckerle, William; Hall, Stephen

    2005-12-30

    In 2002, Gnomon, Inc., entered into a cooperative agreement with the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) for a project entitled, Adaptive Management and Planning Models for Cultural Resources in Oil and Gas Fields in New Mexico and Wyoming (DE-FC26-02NT15445). This project, funded through DOE’s Preferred Upstream Management Practices grant program, examined cultural resource management practices in two major oil- and gas-producing areas, southeastern New Mexico and the Powder River Basin of Wyoming (Figure 1). The purpose of this project was to examine how cultural resources have been investigated and managed and to identify more effective management practices. The project also was designed to build information technology and modeling tools to meet both current and future management needs. The goals of the project were described in the original proposal as follows: Goal 1. Create seamless information systems for the project areas. Goal 2. Examine what we have learned from archaeological work in the southeastern New Mexico oil fields and whether there are better ways to gain additional knowledge more rapidly or at a lower cost. Goal 3. Provide useful sensitivity models for planning, management, and as guidelines for field investigations. Goal 4. Integrate management, investigation, and decision- making in a real-time electronic system. Gnomon, Inc., in partnership with the Wyoming State Historic Preservation Office (WYSHPO) and Western GeoArch Research, carried out the Wyoming portion of the project. SRI Foundation, in partnership with the New Mexico Historic Preservation Division (NMHPD), Statistical Research, Inc., and Red Rock Geological Enterprises, completed the New Mexico component of the project. Both the New Mexico and Wyoming summaries concluded with recommendations how cultural resource management (CRM) processes might be modified based on the findings of this research.

  6. Petrogenesis of the Mount Taylor volcanic field and comparison to the Jemez Mountains volcanic field, New Mexico

    NASA Astrophysics Data System (ADS)

    Fellah, K.; Wolff, J. A.; Goff, F. E.

    2010-12-01

    , consistent with greater depths, and/or lower degrees of, mantle partial melting. The smaller role for crustal contamination at MTVF compared to the JMVF (Rowe et al., 2007) is consistent with a smaller magma flux (MTVF, <0.1 km3/ka; JMVF, ~0.15 km3/ka) and consequent lower degree of crustal heating. References: Perry, F.V., Baldridge, W.S., DePaolo, D.J., and Shafiqullh, M., 1990, Evolution of a magmatic system during continental extension: The Mount Taylor volcanic field, New Mexico: Journal of Geophysical Research, vol. 95. Rowe, M.C., Wolff, J.A., Gardner, J.N., Ramos, F.C., Teasdale, R., and Heikoop, C.E., 2007, Development of a Continental Volcanic Field: Petrogenesis of Pre-Caldera intermediate and Silicic rocks and origin of the Bandelier Magmas, Jemez Mountains (New Mexico, USA): Journal of Petrology, vol. 48, p. 2063-2091.

  7. Measurements and Slope Analyses of Quaternary Cinder Cones, Camargo Volcanic Field, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Gallegos, M. I.; Espejel-Garcia, V. V.

    2012-12-01

    The Camargo volcanic field (CVF) covers ~3000 km2 and is located in the southeast part of the state of Chihuahua, within the Basin and Range province. The CVF represents the largest mafic alkali volcanic field in northern Mexico. Over a 300 cinder cones have been recognized in the Camargo volcanic field. Volcanic activity ranges from 4.7 to 0.09 Ma revealed by 40Ar/39Ar dating methods. Previous studies say that there is a close relationship between the cinder cone slope angle, due to mechanical weathering, and age. This technique is considered a reliable age indicator, especially in arid climates, such as occur in the CVF. Data were acquired with digital topographic maps (DRG) and digital elevation models (DEM) overlapped in the Global Mapper software. For each cone, the average radius (r) was calculated from six measurements, the height (h) is the difference between peak elevation and the altitude of the contour used to close the radius, and the slope angle was calculated using the equation Θ = tan-1(h/r). The slope angles of 30 cinder cones were calculated showing angles ranging from 4 to 15 degrees. A diffusion model, displayed by an exponential relationship between slope angle and age, places the ages of these 30 cones from 215 to 82 ka, within the range marked by radiometric methods. Future work include the analysis of more cinder cones to cover the whole CVF, and contribute to the validation of this technique.

  8. Small biphase wellhead plant for the Cerro Prieto Mexico geothermal field

    SciTech Connect

    Oropeza, A.; Hays, L.

    1996-12-31

    In a system of geothermal wells in a geothermal field, there are different production conditions of the flows, temperatures and pressures. At plants where the installed capacity requires the use of many wells, it is necessary to regulate the well`s pressure to ensure a stable condition for the turbines. Reducing the steam pressure on the wellhead is achieved by using an orifice plate (flash orifice). Use of an orifice plate results in a waste or loss of well pressure that could be utilized for production of electricity. The Cerro Prieto field, operated by the Comision Federal de Electricidad (CFE), has many wells operating at a very high pressure and producing a lot of water. Much of this pressure and water is not utilized in the production of electricity. With the purpose of taking advantage of this pressure CFE has evaluated a proposal by Biphase Energy Co. Biphase has designed and patented a turbine that works directly with the steam and water mixture coming from the wellhead, acting as a separator. Biphase has developed a model of its turbine and successfully operated it in Coso Hot Springs California. Knowing this CFE has signed an agreement with Biphase Energy Company to install and operate a biphasic turbine at the Cerro Prieto geothermal field located near Mexicali, Mexico.

  9. Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

    NASA Astrophysics Data System (ADS)

    Vargas, Carlos; Ortega-Guerrero, Adrián

    A regional lacustrine aquitard covers the main aquifer of the metropolitan area of Mexico City. The aquitard's hydraulic conductivity (K') is fundamental for evaluating the natural protection of the aquifer against a variety of contaminants present on the surface and its hydraulic response. This study analyzes the distribution and variation of K' in the plains of Chalco, Texcoco and Mexico City (three of the six former lakes that existed in the Basin of Mexico), on the basis of 225 field-permeability tests, in nests of existing piezometers located at depths of 2-85 m. Tests were interpreted using the Hvorslev method and some by the Bouwer-Rice method. Results indicate that the distribution of K' fits log-Gaussian regression models. Dominant frequencies for K' in the Chalco and Texcoco plains range between 1E-09 and 1E-08 m/s, with similar population means of 1.19E-09 and 1.7E-09 m/s, respectively, which are one to two orders of magnitude higher than the matrix conductivity. In the Mexico City Plain the population mean is near by one order of magnitude lower; K'=2.6E-10 m/s. The contrast between the measured K' and that of the matrix is attributed to the presence of fractures in the upper 25-40 m, which is consistent with the findings of previous studies on solute migration in the aquitard. Un imperméable régional d'origine lacustre recouvre le principal aquifère de la zone urbaine de la ville de Mexico. La conductivité hydraulique K' de cet imperméable est fondamentale pour évaluer la protection naturelle de l'aquifère, contre les différents contaminants présents en surface, et sa réponse hydraulique. Cette étude analyse et les variations de K' dans les plaines de Chalco, Texcoco et Mexico (trois des six anciens lacs qui existaient dans le Bassin de Mexico), sur la base de 225 essais de perméabilité sur le terrain, réalisés en grappes dans des piézomètres existants entre 2 et 85 m de profondeur. Les essais ont été interprétés avec la m

  10. ADAPTIVE MANAGEMENT AND PLANNING MODELS FOR CULTURAL RESOURCES IN OIL & GAS FIELDS IN NEW MEXICO AND WYOMING

    SciTech Connect

    Peggy Robinson

    2004-07-01

    This report contains a summary of activities of Gnomon, Inc. and five subcontractors that have taken place during the first six months of 2004 (January 1, 2004-June 30, 2004) under the DOE-NETL cooperative agreement: ''Adaptive Management and Planning Models for Cultural Resources in Oil & Gas Fields in New Mexico and Wyoming'', DE-FC26-02NT15445. Although Gnomon and all five subcontractors completed tasks during these six months, most of the technical experimental work was conducted by the subcontractor, SRI Foundation (SRIF). SRIF created a sensitivity model for the Azotea Mesa area of southeastern New Mexico that rates areas as having a very good chance, a good chance, or a very poor chance of containing cultural resource sites. SRIF suggested that the results of the sensitivity model might influence possible changes in cultural resource management (CRM) practices in the Azote Mesa area of southeastern New Mexico.

  11. ADAPTIVE MANAGEMENT AND PLANNING MODELS FOR CULTURAL RESOURCES IN OIL & GAS FIELDS IN NEW MEXICO AND WYOMING

    SciTech Connect

    Peggy Robinson

    2004-01-01

    This report contains a summary of activities of Gnomon, Inc. and five subcontractors that have taken place during the second six months (July 1, 2003-December 31, 2003) under the DOE-NETL cooperative agreement: ''Adaptive Management and Planning Models for Cultural Resources in Oil & Gas Fields in New Mexico and Wyoming'', DE-FC26-02NT15445. Although Gnomon and all five subcontractors completed tasks during these six months, most of the technical experimental work was conducted by the subcontractor, SRI Foundation (SRIF). SRIF created a sensitivity model for the Loco Hills area of southeastern New Mexico that rates areas as having a very good chance, a good chance, or a very poor chance of containing cultural resource sites. SRIF suggested that the results of the sensitivity model might influence possible changes in cultural resource management (CRM) practices in the Loco Hills area of southeastern New Mexico.

  12. Multi-scale Hydrologic Modeling of the White Sands Dune Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Bourret, S. M.; Newton, B. T.

    2014-12-01

    The shallow groundwater flow system of White Sands dune field, located within the arid to semi-arid Tularosa Basin of Southern New Mexico, likely stabilizes the base of the largest gypsum dune field in the world. The dune is saturated throughout nearly its entire accumulation thickness, resulting in a shallow water table (< 3 ft bgs) in the inter-dunal areas. Water table elevation influences the spatial extent of the dune field and accumulation thickness. The White Sands National Monument (WHSA) is concerned that lowering the water table may lead to increased scour and migration of the dune field, which could be unfavorable to the preservation of the flora and fauna that have adapted to survive there. In response to projected increases in groundwater pumping in the regional Tularosa Basin groundwater system, changes in surface water use, and the threat of climate change, the WHSA is interested in understanding how these changes on a regional scale may impact the shallow dune field aquifer. Mathematical modeling techniques on varying spatial and temporal scales are used to characterize the relative importance of the sources of water (local vs. regional) to the dune aquifer, and to quantify the timescales on which changes may affect the water table in the dune field. A 2-dimensional, dune-scale heat and fluid flow model uses the seasonal temperature fluctuations to estimate the vertical and horizontal flow of water from the regional system to the dune field aquifer. We have also constructed a 2-dimensional, hydrologic model to characterize the regional groundwater flow regime near to the dune aquifer system, as well as across the Tularosa Basin to a depth of 6 km. Additionally, a 3-dimensional, hydrologic model of the Tularosa Basin and the White Sands dune field quantifies hydrologic characteristics, sources and sinks of groundwater in the basin and at the dune field. Computed and observed salinity, groundwater residence times, and water level data are the primary

  13. Cedar Hills Field, San Juan County, New Mexico: a multi-well coal degasification project, San Juan Basin, New Mexico-a case study

    SciTech Connect

    Perlman, S.H.

    1985-05-01

    Amoco Production Company is operating a multi-well coal degasification site, Cedar Hills field, in San Juan County, New Mexico. Data presented here have been made available by Amoco at public hearings before the New Mexico Oil and Gas Commission. The Cedar Hills field produces from the lowermost coal bed in the Cretaceous, Fruitland Formation, stratigraphically positioned above the Pictured Cliffs Sandstone. The coal bed reservoir is 18-20 ft (5-6 m) thick at a depth of 2800 ft (853 m). The first well in this field was the Amoco 1 Cahn, completed in 1977 with an initial production of 200-300 MCFGD and 200-300 BWPD. These rates increased to 1.5 MMCFGD and 80 BWPD by January 1984. This well's production history exhibits a negative decline (incline) curve. Gas analyses, water analyses, and reservoir pressure data strongly indicate that the 1 Cahn well is producing from the Fruitland coal bed rather than the Fruitland sandstones or underlying Pictured Cliffs Sandstone.

  14. Quantification of deep percolation from two flood-irrigated alfalfa field, Roswell Basin, New Mexico

    USGS Publications Warehouse

    Roark, D. Michael; Healy, D.F.

    1998-01-01

    For many years water management in the Roswell ground-water basin (Roswell Basin) and other declared basins in New Mexico has been the responsibility of the State of New Mexico. One of the water management issues requiring better quantification is the amount of deep percolation from applied irrigation water. Two adjacent fields, planted in alfalfa, were studied to determine deep percolation by the water-budget, volumetric-moisture, and chloride mass-balance methods. Components of the water-budget method were measured, in study plots called borders, for both fields during the 1996 irrigation season. The amount of irrigation water applied in the west border was 95.8 centimeters and in the east border was 169.8 centimeters. The total amount of precipitation that fell during the irrigation season was 21.9 centimeters. The increase in soil-moisture storage from the beginning to the end of the irrigation season was 3.2 centimeters in the west border and 8.8 centimeters in the east border. Evapotranspiration, as estimated by the Bowen ratio energy balance technique, in the west border was 97.8 centimeters and in the east border was 101.0 centimeters. Deep percolation determined using the water-budget method was 16.4 centimeters in the west border and 81.6 centimeters in the east border. An average deep percolation of 22.3 centimeters in the west border and 31.6 centimeters in the east border was determined using the volumetric-moisture method. The chloride mass-balance method determined the multiyear deep percolation to be 15.0 centimeters in the west border and 38.0 centimeters in the east border. Large differences in the amount of deep percolation between the two borders calculated by the water-budget method are due to differences in the amount of water that was applied to each border. More water was required to flood the east border because of the greater permeability of the soils in that field and the smaller rate at which water could be applied.

  15. Description of piezometers installed in the Duranes well field area, Albuquerque, New Mexico

    USGS Publications Warehouse

    Thorn, C.R.

    1998-01-01

    Since 1993, the aquifer system in the Middle Rio Grande Basin, and particularly in the Albuquerque area, has been the focus of studies to further define the extent of the most productive parts of the aquifer and to gain a better understanding of ground-water/surface-water interactions. Twenty-one piezometers were installed during January and February 1997 at five sites in the Duranes well field area in Albuquerque, New Mexico, to allow for concentrated collection of hydraulic-head data. This concentrated collection of shallow hydraulic-head data may lead to a better understanding of the effects of ground-water production on the Rio Grande near a City of Albuquerque well field. Each piezometer was installed in a hole augered by a rig using hollow-stem auger flights. All piezometers are constructed of flush-joint polyvinyl chloride casing with 5-foot polyvinyl chloride screens. The uppermost 2 feet of the piezometer casing is covered by a steel casing with a locking lid. Driller's logs and geophysical logs were collected from the deepest hole and piezometer, respectively, at each site. This report describes the piezometers installed and presents initial water- level data for all piezometers.

  16. Field guide to Cretaceous-tertiary boundary sections in northeastern Mexico

    NASA Technical Reports Server (NTRS)

    Keller, Gerta; Stinnesbeck, Wolfgang; Adatte, Thierry; Macleod, Norman; Lowe, Donald R.

    1994-01-01

    This guide was prepared for the field trip to the KT elastic sequence of northeastern Mexico, 5-8 February 1994, in conjunction with the Conference on New Developments Regarding the KT Event and Other Catastrophes in Earth History, held in Houston, Texas. The four-day excursion offers an invaluable opportunity to visit three key outcrops: Arroyo El Mimbral, La Lajilla, and El Pinon. These and other outcrops of this sequence have recently been interpreted as tsunami deposits produced by the meteorite impact event that produced the 200 to 300-km Chicxulub basin in Yucatan, and distributed ejecta around the world approximately 65 m.y. ago that today is recorded as a thin clay layer found at the K/T boundary. The impact tsunami interpretation for these rocks has not gone unchallenged, and others examining the outcrops arrive at quite different conclusions: not tsunami deposits but turbidites; not KT at all but 'upper Cretaceous.' Indeed, it is in hopes of resolving this debate through field discussion, outcrop evaluation, and sampling that led the organizers of the conference to sanction this field trip. This field guide provides participants with background information on the KT clastic sequence outcrops and is divided into two sections. The first section provides regional and logistical context for the outcrops and a description of the clastic sequence. The second section presents three representative interpretations of the outcrops by their advocates. There is clearly no way that these models can be reconciled and so two, if not all three, must be fundamentally wrong. Readers of this guide should keep in mind that many basic outcrop observations that these models are based upon remain unresolved. While great measures were taken to ensure that the information in the description section was as objective as possible, many observations are rooted in interpretations and the emphasis placed on certain observations depends to some degree upon the perspective of the author.

  17. Field guide to Cretaceous-tertiary boundary sections in northeastern Mexico

    NASA Astrophysics Data System (ADS)

    Keller, Gerta; Stinnesbeck, Wolfgang; Adatte, Thierry; MacLeod, Norman; Lowe, Donald R.

    This guide was prepared for the field trip to the KT elastic sequence of northeastern Mexico, 5-8 February 1994, in conjunction with the Conference on New Developments Regarding the KT Event and Other Catastrophes in Earth History, held in Houston, Texas. The four-day excursion offers an invaluable opportunity to visit three key outcrops: Arroyo El Mimbral, La Lajilla, and El Pinon. These and other outcrops of this sequence have recently been interpreted as tsunami deposits produced by the meteorite impact event that produced the 200 to 300-km Chicxulub basin in Yucatan, and distributed ejecta around the world approximately 65 m.y. ago that today is recorded as a thin clay layer found at the K/T boundary. The impact tsunami interpretation for these rocks has not gone unchallenged, and others examining the outcrops arrive at quite different conclusions: not tsunami deposits but turbidites; not KT at all but 'upper Cretaceous.' Indeed, it is in hopes of resolving this debate through field discussion, outcrop evaluation, and sampling that led the organizers of the conference to sanction this field trip. This field guide provides participants with background information on the KT clastic sequence outcrops and is divided into two sections. The first section provides regional and logistical context for the outcrops and a description of the clastic sequence. The second section presents three representative interpretations of the outcrops by their advocates. There is clearly no way that these models can be reconciled and so two, if not all three, must be fundamentally wrong. Readers of this guide should keep in mind that many basic outcrop observations that these models are based upon remain unresolved. While great measures were taken to ensure that the information in the description section was as objective as possible, many observations are rooted in interpretations and the emphasis placed on certain observations depends to some degree upon the perspective of the author.

  18. Paleomagnetic evidence for an episodic eruptive history of the Cerros del Rio volcanic field, New Mexico

    NASA Astrophysics Data System (ADS)

    Hudson, M. R.; Thompson, R. A.

    2011-12-01

    The Pliocene to Quaternary (~2.6-1.14 Ma) Cerros del Rio volcanic field of northern New Mexico forms a dissected basaltic plateau sourced by multiple eruptive centers. Paleomagnetic data compliment geologic mapping, geochronologic and geochemical data to define the spatial and temporal eruptive history of Cerros del Rio volcanic deposits. The preserved stratigraphic sequence reflects three principal phases of volcanism; 1) 2.7-2.6 Ma, 2) 2.5-2.2 Ma, and 3) 1.5-1.1 Ma. Paleomagnetic data collected from 85 sites that span the area of the volcanic field largely sample phase-1 deposits that record the Guass normal-polarity chron or phase-2 deposits that record the Matuyama reversed-polarity chron. A grand mean of individual sites (excluding transitional directions) is D = 352.8°, I = 49.7°, k= 14, a95 = 3.9. However, normal- and reversed-polarity group means are not statistically antipodal, with the normal-polarity inclination being significantly shallower than an expected (55°) dipole inclination. This failed reversal test suggests that paleosecular variation has not be fully averaged within both polarity groups, despite a basis on abundant data from multiple eruptive centers. Compared to variation recorded by the full volcanic field, site directions from individual eruptive centers have restricted dispersion, indicating that the centers formed quickly relative to paleosecular variation. Grouping data within individual eruptive centers to calculate eruptive-group means (EGM), directions of the normal- and reversed-polarity EGM remain skewed from antipodal. Modal analysis demonstrates the presence of multiple directional clusters among the normal-polarity EGM whereas the frequency distribution of reversed polarity EGM are symmetrical about their maximum. These paleomagnetic directional characteristics indicate that voluminous phase-1 deposits of the Cerros del Rio volcanic field probably erupted episodically during short time intervals and that several individual

  19. A 3D model of crustal magnetization at the Pinacate Volcanic Field, NW Sonora, Mexico

    NASA Astrophysics Data System (ADS)

    García-Abdeslem, Juan; Calmus, Thierry

    2015-08-01

    The Pinacate Volcanic Field (PVF) is located near the western border of the southern Basin and Range province, in the State of Sonora NW Mexico, and within the Gulf of California Extensional Province. This volcanic field contains the shield volcano Santa Clara, which mainly consists of basaltic to trachytic volcanic rocks, and reaches an altitude of 1200 m. The PVF disrupts a series of discontinuous ranges of low topographic relief aligned in a NW direction, which consist mainly of Proterozoic metamorphic rocks and Proterozoic through Paleogene granitoids. The PVF covers an area of approximately 60 by 55 km, and includes more than 400 well-preserved cinder cones and vents and eight maar craters. It was active from about 1.7 Ma until about 13 ka. We have used the ages and magnetic polarities of the volcanic rocks, along with mapped magnetic anomalies and their inverse modeling to determine that the Pinacate Volcanic Field was formed during two volcanic episodes. The oldest one built the Santa Clara shield volcano of basaltic and trachytic composition, and occurred during the geomagnetic Matuyama Chron of reverse polarity, which also includes the normal polarity Jaramillo and Olduvai Subchrons, thus imprinting both normal and reverse magnetization in the volcanic products. The younger Pinacate series of basaltic composition represents monogenetic volcanic activity that extends all around the PVF and occurred during the subsequent geomagnetic Brunhes Chron of normal polarity. Magnetic anomalies toward the north of the Santa Clara volcano are the most intense in the PVF, and their inverse modeling indicates the presence of a large subsurface body magnetized in the present direction of the geomagnetic field. This suggests that the magma chambers at depth cooled below the Curie temperature during the Brunhes Chron.

  20. Experimental porcine rubulavirus (La Piedad-Michoacan virus) infection in pregnant gilts.

    PubMed

    Hernández-Jáuregui, P; Ramírez Mendoza, H; Mercado García, C; Moreno-López, J; Kennedy, S

    2004-01-01

    Porcine rubulavirus (La Piedad-Michoacan virus) (PoRV-LPMV) is a member of the Paramyxoviridae family that causes encephalitis in young piglets and infertility in adult sows and boars. Infertility in sows naturally infected by PoRV-LPMV is characterized by an increased number of returns to oestrus, stillbirths and mummified fetuses. In this study, nine seronegative gilts were inoculated intranasally with the PAC-3 strain of PoRV-LPMV at week 6 or 10 of gestation. These animals were then killed at weeks 8 or 15 of gestation (seven gilts) or after natural parturition (two gilts). Four control gilts were mock-infected at gestation week 6 or 10 and killed between 2 and 4 weeks later. Gross lesions of focal congestion and haemorrhage were seen in the placenta and endometrium of one gilt infected at gestation week 6 and one infected at gestation week 10. PoRV-LPMV was isolated, at 2-6 weeks post-inoculation (pi), from lung, tonsils, ovary, placenta, uterus and lymph nodes of three of the gilts infected at gestation week 6 and at 2-3 weeks pi from lung, tonsil and ovary of two gilts infected at gestation week 10. Many of the fetuses of eight infected gilts were smaller than normal and had dermal ecchymoses. Dehydrated or mummified fetuses were present in six of the infected gilts but not in any control animal. PoRV-LPMV was isolated from brain, lung and liver of fetuses from two gilts infected at gestation week 6, and from two infected at gestation week 10. These results indicate that, after experimental infection, PoRV can replicate in tissues of seronegative pregnant gilts, cross the placenta, and cause fetal death and mummification.

  1. Statistical analysis of eruptive vent distribution from post-subduction monogenetic fields in Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Germa, A.; Cañon-Tapia, E.; Connor, L.; Le Corvec, N.

    2012-04-01

    Volcanism in Baja California (BC, Mexico) was active from the end of the subduction of the Farallon plate (12.5Ma) until recently (< 1Ma). Most of this volcanism formed twelve volcanic fields, seven of them being monogenetic, delineating a ~600-km-long array parallel to the Gulf of California. Previous studies on these fields have focused on the compositional diversity of magmatic products. Although geochemistry and ages of few lava flows are constrained, only two studies investigated the spatial distribution of the eruptive vents of San Borja. Within a monogenetic volcanic field, cone alignments and linear arrays are considered to reflect the geometry of feeder dikes formed either parallel to the maximum principal stress (σ1) in the lithosphere or using pre-existing crustal fractures. These intrinsic local structures will be compared with the shape of the field, which could reflect the shape of the source at depth. Using satellite imagery to define the location of eruptive centres on four monogenetic volcanic fields from central Baja California (Jaraguay, San Borja, Santa Clara, and San Ignacio), we completed statistical analyses of their spatial distribution. Using commercially available GIS software, spatial density analysis, and statistical scripts, each volcanic field was analysed for the number and density of vents, clustering, vent spacing and alignment azimuths. Our preliminary results reveal that vent densities are within the range of 0.001 to 0.2 vents / 100 km2. Eruptive vents are generally clustered, with density higher than 0.1 vents/100 km2. A common elongation direction trends N135° to N152° in most clusters and fields. We thus propose a NW-SE direction as the preferred orientation of the maximum principal stress (σ1), direction that needs to be confirmed by azimuths of the vents alignments. Using a combination of different computational methods, this study allows to quantify the influence of tectonic stresses at the deep and shallow level within

  2. Internal Structure of the Tuxtla Volcanic Field, Eastern mexico, Derived from Gravity and Aeromagnetic data.

    NASA Astrophysics Data System (ADS)

    Espindola, J. M.; Lopez Loera, H.; Zamora-Camacho, A.; Mena, M.

    2016-12-01

    The TVF is a basaltic volcanic field located in the western margin of the Gulf of Mexico in the Mexican State of Veracruz, about 230 km to the SSE of the easternmost tip of the Trans-Mexican Volcanic Belt, and about the same distance from El Chichon volcano, in the Chiapanecan Volcanic Arc, to the SE. It is separated from both volcanic chains also in composition as its rocks are predominantly alkaline. These characteristics prompt questions about its origin, more so since, one of the large volcanoes of the field, San Martin Tuxtla, erupted in 1793 CE. The TVF stands out from the lowlands of the Veracruz margins and is approximately surrounded by the 100 m contour line, while the surrounding areas along the Gulf of Mexico shoreline lie below this contour. Assuming that the rocks above this contour were deposited by the volcanic activity in the area, a good estimate of its volume is obtained by calculating the amount of material contained above this contour. We performed this calculation from the digital elevation model of the area received from restitutions carried out by Mexicós National Institute of Statistics, Geography, and Informatics (Spanish acronym: INEGI). We obtained a total amount of 1300 km3 for this volume. To understand more about the volcanism that has deposited this volume of products, we analyzed the gravimetric and aeromagnetic anomalies of the area and obtained a density model of the causative body. We got a body with a somewhat flattened top at 16 km below sea level from the inversion of the regional. Three separate slender bodies with tops 6 km deep were obtained from the inversion of the residual. The gravity and magnetic anomalies, as well as the inferred source bodies that produce those geophysical anomalies, lie between two large regional faults (Sontecomapan and Catemaco faults), which are proposed as flower structures associated with an inferred deep-seated fault termed the Veracruz Fault. We suggest that the process leading to the

  3. Geomagnetic field for the past 5 Myr recorded in lava flows from British Columbia, Patagonia, and Mexico

    NASA Astrophysics Data System (ADS)

    Mejia, Victoria

    2005-11-01

    Paleosecular variation (PSV) and time averaged field (TAF) results recorded in lava flows younger than 5 million years are presented. The targeted areas of studies are several volcanic fields from British Columbia (mainly the Silverthrone, Garibaldi, and Wells Park volcanic fields), Southern Patagonia (the Pali-Aike volcanic field and Meseta Viscachas lavas), and Mexico (the Trans-Mexican volcanic belt and several volcanic areas in San Luis Potosi). The purpose of this investigation was to obtain high quality paleomagetic data suitable to test the presence or absence of permanent non dipolar components of the field that have been interpreted from studies carried out with less rigor. The mean directions in the areas of British Columbia and Patagonia (roughly at 50° N and 50° S latitude) coincide with the expected geocentric axial dipole (GAD) at these areas. The presence of a quadrupolar component of the field is difficult to discard because it is expected to produce only about 1° shallower inclinations. The mean direction in the area of Mexico coincides with a GAD plus a 5% quadrupole. The VGP scatter in the three areas of study coincides with Model G. The asymmetry between the northern and southern hemisphere of the present magnetic field and particularly the 20° inclination anomaly relative to GAD in Patagonia, are not observed in the paleomagnetic data obtained, implying that the present field configuration is relatively recent. The results confirm that axial components prevail in the time-averaged field.

  4. The Eruptive History of the Talpa-Mascota-San Sebastian Volcanic Field in Western Mexico.

    NASA Astrophysics Data System (ADS)

    Ownby, S.; Lange, R.; Carmichael, I. S.; Hall, C.

    2004-12-01

    The eruptive history of the Talpa-Mascota-San Sebastian (TMSS) volcanic field in the Jalisco Block (JB) of western Mexico is presented. The JB is bounded by the Tepic-Zacoalco and Colima grabens, as well as the Middle America Trench where the Rivera plate subducts beneath North America. The TMSS volcanic field spans ˜2030 km2 and contains ˜123 small cones and flows of minette, absarokite, basic hornblende lamprophyre, basaltic andesite, and andesite. The petrology of these lavas is described in Lange and Carmichael (1990, 1991) and Carmichael et al. (1996). Of the ˜123 distinguishable eruptive units within this volcanic field, 26 samples have been dated by the 40Ar/39Ar method, and are combined with 10 dates from a previous abstract and nine dates from the literature (for a total of 45). The oldest lavas (2.35 to 0.5 Ma) are found in the Talpa region, whereas the youngest lavas (predominantly < 0.5 Ma) are found in the Mascota and San Sebastain regions to the north. There is thus a clear trend of volcanism becoming younger to the north, away from the trench. On the basis of these ages, field mapping, and the use of ortho airphotos and DEMs, it is estimated that a combined volume of < 12 km3 erupted in the last 1 Myr. The dominant lava type is basaltic andesite ( ˜44 %), followed by minette ( ˜20 %), basic, hornblende lamprophyre ( ˜17 %), andesite ( ˜13 %), and absarokite ( ˜6 %). Thus more than half of the eruptive material (57 %) is andesite and basaltic andesite, which erupted in close spatial and temporal association with the highly potassic lavas. There is no time progression to the type of magma erupted. The volumes of the potassic lava types are dwarfed by the amount of intermediate, calc-alkaline magma ( ˜360 km3) that has erupted over the same time period (< 1 Ma) within the Tepic-Zacoalco graben in western Mexico. These age results confirm that the potassic lavas of Mascota (not unlike those erupted 3-4 Myr ago in the Sierra Nevada batholith

  5. Internal architecture of the Tuxtla volcanic field, Veracruz, Mexico, inferred from gravity and magnetic data

    NASA Astrophysics Data System (ADS)

    Espindola, Juan Manuel; Lopez-Loera, Hector; Mena, Manuel; Zamora-Camacho, Araceli

    2016-09-01

    The Tuxtla Volcanic Field (TVF) is a basaltic volcanic field emerging from the plains of the western margin of the Gulf of Mexico in the Mexican State of Veracruz. Separated by hundreds of kilometers from the Trans-Mexican Volcanic Belt to the NW and the Chiapanecan Volcanic Arc to the SE, it stands detached not only in location but also in the composition of its rocks, which are predominantly alkaline. These characteristics make its origin somewhat puzzling. Furthermore, one of the large volcanoes of the field, San Martin Tuxtla, underwent an eruptive period in historical times (CE 1793). Such volcanic activity conveys particular importance to the study of the TVF from the perspective of volcanology and hazard assessment. Despite the above circumstances, few investigations about its internal structure have been reported. In this work, we present analyses of gravity and aeromagnetic data obtained from different sources. We present the complete Bouguer anomaly of the area and its separation into regional and residual components. The aeromagnetic data were processed to yield the reduction to the pole, the analytic signal, and the upward continuation to complete the interpretation of the gravity analyses. Three-dimensional density models of the regional and residual anomalies were obtained by inversion of the gravity signal adding the response of rectangular prisms at the nodes of a regular grid. We obtained a body with a somewhat flattened top at 16 km below sea level from the inversion of the regional. Three separate slender bodies with tops 6 km deep were obtained from the inversion of the residual. The gravity and magnetic anomalies, as well as the inferred source bodies that produce those geophysical anomalies, lie between the Sontecomapan and Catemaco faults, which are proposed as flower structures associated with an inferred deep-seated fault termed the Veracruz Fault. These fault systems along with magma intrusion at the lower crust are necessary features to

  6. Geologic and geophysical investigations of the Zuni-Bandera volcanic field, New Mexico

    SciTech Connect

    Ander, M.E.; Heiken, G.; Eichelberger, J.; Laughlin, A.W.; Huestis, S.

    1981-05-01

    A positive, northeast-trending gravity anomaly, 90 km long and 30 km wide, extends southwest from the Zuni uplift, New Mexico. The Zuni-Bandera volcanic field, an alignment of 74 basaltic vents, is parallel to the eastern edge of the anomaly. Lavas display a bimodal distribution of tholeiitic and alkalic compositions, and were erupted over a period from 4 Myr to present. A residual gravity profile taken perpendicular to the major axis of the anomaly was analyzed using linear programming and ideal body theory to obtain bounds on the density contrast, depth, and minimum thickness of the gravity body. Two-dimensionality was assumed. The limiting case where the anomalous body reaches the surface gives 0.1 g/cm/sup 3/ as the greatest lower bound on the maximum density contrast. If 0.4 g/cm/sup 3/ is taken as the geologically reasonable upper limit on the maximum density contrast, the least upper bound on the depth of burial is 3.5 km and minimum thickness is 2 km. A shallow mafic intrusion, emplaced sometime before Laramide deformation, is proposed to account for the positive gravity anomaly. Analysis of a magnetotelluric survey suggests that the intrusion is not due to recent basaltic magma associated with the Zuni-Bandera volcanic field. This large basement structure has controlled the development of the volcanic field; vent orientations have changed somewhat through time, but the trend of the volcanic chain followed the edge of the basement structure. It has also exhibited some control on deformation of the sedimentary section.

  7. Dynamic deformations of shallow sediments in the Valley of Mexico, Part II: Single-station estimates

    USGS Publications Warehouse

    Singh, S.K.; Santoyo, M.; Bodin, P.; Gomberg, J.

    1997-01-01

    We develop simple relations to estimate dynamic displacement gradients (and hence the strains and rotations) during earthquakes in the lake-bed zone of the Valley of Mexico, where the presence of low-velocity, high-water content clays in the uppermost layers cause dramatic amplification of seismic waves and large strains. The study uses results from a companion article (Bodin et al., 1997) in which the data from an array at Roma, a lake-bed site, were analyzed to obtain displacement gradients. In this article, we find that the deformations at other lake-bed sites may differ from those at Roma by a factor of 2 to 3. More accurate estimates of the dominant components of the deformation at an individual instrumented lake-bed site may be obtained from the maximum horizontal velocity and displacement, ??max and umax, at the surface. The maximum surface strain ??max is related to ??max by ??max = ??max/C, with C ??? 0.6 km/sec. From the analysis of data from sites equipped with surface and borehole sensors, we find that the vertical gradient of peak horizontal displacement (??umax/??z) computed from sensors at 0 and 30 m equals (umax)z = 0/??z, ??z = 30 m, within a factor of 1.5. This is the largest gradient component, and the latter simple relation permits its estimation from surface records alone. The observed profiles of umax versus depth suggest a larger gradient in some depth range of 10 to 20 m, in agreement with synthetic calculations presented in Bodin et al. (1997). From the free-field recordings of the 19 September 1985 Michoacan earthquake, we estimate a maximum surface strain, ??max, between 0.05% and 0.11%, and a lower bound for the peak vertical gradient (??umax/??z) between 0.3% and 1.3%. This implies that (1) the extensive failure of water pipe joints during the Michoacan earthquake in the valley occurred at axial strains of about 0.1%, not 0.38% as previously reported, and (2) the clays of the valley behave almost linearly even at shear strain of about 1

  8. Air Quality in Megacities: Lessons Learned from Mexico City Field Measurements

    NASA Astrophysics Data System (ADS)

    Molina, L. T.

    2014-12-01

    More than half of the world's population now lives in urban areas because of the opportunities for better jobs, access to city services, cultural and educational activities, and a desire for more stimulating human interaction. At the same time, many of these urban centers are expanding rapidly, giving rise to the phenomenon of megacities. In recent decades air pollution has become not only one of the most important environmental problems of megacities, but also presents serious consequences to human health and ecosystems and economic costs to society. Although the progress to date in combating air pollution problems in developed and some developing world megacities has been impressive, many challenges remain including the need to improve air quality while simultaneously mitigating climate change. This talk will present the results and the lessons learned from field measurements conducted in Mexico City Metropolitan Area - one of the world's largest megacities - over the past decade. While each city has its own unique circumstances, the need for an integrated assessment approach in addressing complex environmental problems is the same. There is no single strategy in solving air pollution problems in megacities; a mix of policy measures based on sound scientific findings will be necessary to improve air quality, protect public health, and mitigate climate change.

  9. Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

    USGS Publications Warehouse

    Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

    2002-01-01

    Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

  10. A GEOLOGICAL AND GEOPHYSICAL STUDY OF THE BACA GEOTHERMAL FIELD, VALLES CALDERA, NEW MEXICO

    SciTech Connect

    Wilt, M.; Haar, S.V.

    1982-03-01

    The Baca location {number_sign}1 geothermal field is located in north-central New Mexico within the western half of the Plio-Pleistocene valles Caldera. Steam and hot water are produced primarily from the northeast-trending Redondo Creek graben, where downhole temperatures exceed 500 F. Stratigraphically the reservoir region can be described as a five-layer sequence that includes (1) caldera fill and the upper units of the Bandelier ash flow tuff, (2) the lower members of this tuff, which comprise the main reservoir rock at Baca, (3) the Pliocene Paliza Canyon volcanics, (4) Tertiary sands and Paleozoic sedimentary rocks, and (5) Precambrian granitic basement. Production is controlled by fractures and faults that are ultimately related to activity in the Rio Grande Rift system. Geophysically, the caldera is characterized by a gravity minimum and a resistivity low. A 40-mgal gravity minimum over the caldera is due mostly to the relatively low-density volcanics and sediments that fill the caldera and probably bears no relation to deep-seated magmatic sources. Two-dimensional gravity modeling indicates that the depth to Precambrian basement in Redondo Canyon is probably at least 3 km and may exceed 5 km in eastern parts of the caldera. Telluric and magnetotelluric surveys have shown that the reservoir region is associated with low resistivity and that a deep low-resistivity zone correlates well with the depth of the primary reservoir inferred from well data.

  11. A geostatistical method applied to the geochemical study of the Chichinautzin Volcanic Field in Mexico

    NASA Astrophysics Data System (ADS)

    Robidoux, P.; Roberge, J.; Urbina Oviedo, C. A.

    2011-12-01

    The origin of magmatism and the role of the subducted Coco's Plate in the Chichinautzin volcanic field (CVF), Mexico is still a subject of debate. It has been established that mafic magmas of alkali type (subduction) and calc-alkali type (OIB) are produced in the CVF and both groups cannot be related by simple fractional crystallization. Therefore, many geochemical studies have been done, and many models have been proposed. The main goal of the work present here is to provide a new tool for the visualization and interpretation of geochemical data using geostatistics and geospatial analysis techniques. It contains a complete geodatabase built from referred samples over the 2500 km2 area of CVF and its neighbour stratovolcanoes (Popocatepetl, Iztaccihuatl and Nevado de Toluca). From this database, map of different geochemical markers were done to visualise geochemical signature in a geographical manner, to test the statistic distribution with a cartographic technique and highlight any spatial correlations. The distribution and regionalization of the geochemical signatures can be viewed in a two-dimensional space using a specific spatial analysis tools from a Geographic Information System (GIS). The model of spatial distribution is tested with Linear Decrease (LD) and Inverse Distance Weight (IDW) interpolation technique because they best represent the geostatistical characteristics of the geodatabase. We found that ratio of Ba/Nb, Nb/Ta, Th/Nb show first order tendency, which means visible spatial variation over a large scale area. Monogenetic volcanoes in the center of the CVF have distinct values compare to those of the Popocatepetl-Iztaccihuatl polygenetic complex which are spatially well defined. Inside the Valley of Mexico, a large quantity of monogenetic cone in the eastern portion of CVF has ratios similar to the Iztaccihuatl and Popocatepetl complex. Other ratios like alkalis vs SiO2, V/Ti, La/Yb, Zr/Y show different spatial tendencies. In that case, second

  12. Using Acceleration Records as Diffuse Fields for Tomography of the Valley of Mexico City: Synthetic Results

    NASA Astrophysics Data System (ADS)

    Baena, M.; Perton, M.; Molina-Villegas, J. C.; Sanchez-Sesma, F. J.

    2013-12-01

    In order to improve the understanding of the seismic response of Mexico City Valley, we have proposed to perform a tomography study of the seismic wave velocities. For that purpose, we used a collection of acceleration seismograms (corresponding to earthquakes with magnitudes ranging from 4.5 to 8.1 and various epicentral distances to the City) recorded since 1985 in 83 stations distributed across the Valley. The H/V spectral ratios (obtained from average autocorrelations) strongly suggest these movements belong to a 3D generalized diffuse field. Thus, we interpret that cross-correlations between the signals of station pairs are proportional to the imaginary part of the corresponding Green function. Finally, the dispersion curves are constructed from the Green function which lead to the tomography. Other tomographies have already been made around the world using either the seismic coda or seismic noise. We used instead the ensemble of many earthquakes from distant sources that have undergone multiple scattering by the heterogeneities of the Earth and assume the wave fields are equipartitioned. The purpose of the present study is to describe the different steps of the data processing by using synthetic models. The wave propagation within an alluvial basin is simulated using the Indirect Boundary Element Method (IBEM) in 2D configuration for the propagation of P and SV waves. The theoretical Green function for a station pair is obtained by placing a unit force at one station and a receiver at the other. The valley illumination is composed by incoming waves which are simulated using distant independent sources and several diffractors. Data process is validated by the correct retrieval the theoretical Green function. We present here the in-plane Green function for the P-SV case and show the dispersion curves constructed from the cross-correlations compared with analytic results for a layer over a half-space. ACKNOWLEDGEMENTS. This study is partially supported by AXA

  13. A New Method To Determin The Useful Life of La Muralla Well Field, Guanajuato, Mexico.

    NASA Astrophysics Data System (ADS)

    Alfredo, Ramos L. J.; Alejandra, Cortes S.; Alejandro, Ramirez G.; Luis, Cruz J.; Kevin, Johannesson H.; Ismael, Sandoval M.

    The systems of supply and waste water of the city of Leon, Guanajuato, Mexico has been continuously monitoring by hydrochemistry methods. Significant volume of water supply to the Leon city, comes from the well field of La Muralla, extracted from the aquifer that is fed by local and regional flows. The impact in the water quality of the aquifer is originated by the alteration of the hydrodynamic system. The effects are observed in the well field of La Muralla and in some other well of an adjacent Valley where the chlorides have diminished in the last5 years. Applying the monitoring technique of chlorides, the lineal regressions to the chemical analyses of the wells in this area, were used to estimate the time of useful life for each well. The decrease in the content of this conservative ion indicates that the contribution of regional flows is insufficient due to the intense exploitation. The tendency in the negative slope of the meteoric line in chloride content indicates that at some time when the evolution line of the aquifer will intercept this line, the reserves of water in the aquifer in exploitation will be finished; for the depths in that the influence of the regional recharge has influence. Results of chlorides during the observation period between 1994 and 1999, let us to predict an average of useful life for the wells of La Muralla with the next values: 17.4 years, with a 12 year minimum and a 51.6 year maximum, with a 8.8 year-old standard deviation.

  14. Eruptive Productivity of the Ceboruco-San Pedro Volcanic Field, Nayarit, Mexico

    NASA Astrophysics Data System (ADS)

    Frey, H. M.; Lange, R. A.; Hall, C. M.; Delgado-Granados, H.

    2002-12-01

    High-precision 40Ar/39Ar geochronology coupled with GIS spatial analysis provides constraints on magma eruption rates over the past 1 Myr of the Ceboruco-San Pedro volcanic field (1870 km2), located in the Tepic-Zacoalco rift in western Mexico. The volcanic field is part of the Trans Mexican Volcanic arc and is dominated by the andesitic-dacitic stratocone of Volcan Ceboruco and includes peripheral fissure-fed flows, domes, and monogenetic cinder cones. The ages of these volcanic features were determined using 40Ar/39Ar laser step-heating techniques on groundmass or mineral separates, with 78% of the 52 analyses yielding plateau ages with a 2 sigma error < 50 kyrs. The volumes were determined using high resolution (1:50,000) digital elevation models, orthophotos, and GIS software, which allowed for the delineation of individual volcanic features, reconstruction of the pre-eruptive topography, and volume calculations by linear interpolation. The relative proportions of the 80 km3 erupted over the past 1 Myr are 14.5% basaltic andesite, 64.5% andesite, 20% dacite, and 1% rhyolite, demonstrating the dominance of intermediate magma types (in terms of silica content). Overall, there appears to be no systematic progression in the eruption of different magma types (e.g., basalt, andesite, dacite, etc.) with time. However, more than 75% of the total volume of lava within the Ceboruco-San Pedro volcanic field erupted in the last 100 kyrs. This reflects the youthfulness of Volcan Ceboruco, which was constructed during the last 50 kyrs and has a present day volume of 50 +/- 2.5 km3, accounting for 81% of the andesite and 50% of the dacite within the volcanic field. Eleven cinder cones, ranging from the Holocene to 0.37 Ma, display a narrow compositional range, with 52-58 wt% SiO2, 3-5.5 wt% MgO, and relatively high TiO2 concentrations (0.9-1.8 wt%). The total volume of the cinder cones is 0.83 km3. No lavas with < 51 wt% SiO2 have erupted in the past 1 Myr. Peripheral

  15. Lightning Mapping and Electric Field Change Observations of a Stationary New Mexico Storm

    NASA Astrophysics Data System (ADS)

    Krehbiel, P. R.; Rison, W.; Hunyady, S. J.; Edens, H. E.; Sonnenfeld, R. G.; Aulich, G. D.

    2010-12-01

    On August 23, 2010 a classic airmass thunderstorm occurred over high plains immediately east of the Langmuir Laboratory mountaintop observatory in central New Mexico. The energetic storm developed around 2:30 pm MDT (2030 UTC) and remained essentially stationary over its complete lifetime of about 2 hours. The complete sequence of lightning was recorded both by the 16-station Langmuir Laboratory Lightning Mapping Array (LMA) and by several electrostatic field change stations around and beneath the storm. The LMA and Delta-E data are both of very high quality and sensitivity. In this initial study we report on the lightning-inferred electrical structure of the storm and on estimated charging currents determined from a simple electrodynamic model of the storm. The electric field change measurements, in combination with the detailed 3-D mapping results, can be used to determine the amounts of charge involved in individual strokes and parts of flashes for comparison and improvement of the modeling. The LMA data regularly detected isolated attempted breakdown events at repeated locations at mid- to high altitudes in the storm that were clearly indicative of localized high-field regions. The attempted breakdown events were often exact pre-cursors of the initial breakdown of full-fledged IC flashes typically several seconds up to several tens of seconds later, but also often did not precurse a subsequent discharge. During both IC and CG flashes, numerous recoil-type, fast negative breakdown events were detected along otherwise undetected positive leader channels in the main, mid-level negative charge region. The localized fast events during IC flashes often repeatedly intensified in strength and number prior to upward negative leader K-events, and then temporarily ceased before starting up again prior to the next K-event. Many of the negative CG flashes in the storm produced strokes with long continuing currents (CCs). The overall electric field changes and hence total

  16. Slim wells for exploration purposes in Mexico

    SciTech Connect

    Vaca Serrano, J.M.E.; Soto Alvarez, M.

    1996-12-31

    To invest in the construction of wells with definitive designs considerably increases the cost of a geothermal electric project in its analysis and definition stage. The Federal Commission for Electricity (Comision Federal de Electricidad, CFE) has concentrated on the task to design wells which casing and cementing programs would provide the minimum installation necessary to reach the structural objective, to confirm the existence of geothermal reservoirs susceptible to commercial exploitation, to check prior geological studies, to define the stratigraphic column and to obtain measurements of pressure, temperature and permeability. Problems of brittle, hydratable and permeable formations with severe circulation losses, must be considered within the design and drilling programs of the wells. This work explains the slim wells designs used in the exploration of three geothermal zones in Mexico: Las Derrumbadas and Acoculco in the State of Puebla and Los Negritos in the State of Michoacan.

  17. Permeable structures at Ceboruco lava dome, Mexico: the challenge of upscaling laboratory measurements to field constraint

    NASA Astrophysics Data System (ADS)

    Lamur, Anthony; Lavallee, Yan; De Angelis, Silvio

    2015-04-01

    Lava domes are, in their lifespan, variably permeable volcanic structures. During magma ascent, construction of a permeable network is facilitated by the coalescence of vesicles and fractures, which regulates magma outgassing and control whether eruption proceeds effusively or explosively. Here, we present a combined laboratory and field study of dome rock permeability, focusing on a ca. 19th century lava dome at Ceboruco, Mexico. The lava dome has a perfectly rounded shape with a diameter of ~80 metres and a height of ~35 metres. The dome consists of blocks ranging in size between centimetres and 5 metres, which reveal a range of porous structures: the rocks are commonly dense, but porosity occasionally reach 38%; some blocks are entirely massive, whilst others display tensile and shear fractures. Microscopic analysis reveals and equally intricate fracture networks. Permeability measurements are currently being performed on 4 rocks (with different porosities) in a hydrostatic pressure vessel at confining pressures of 6, 10, 15, 20, 30 and 40 MPa and averaged pore pressure of 5 MPa (with differential of 1 MPa). For each sample, the uniaxial compressive strength will be determined and permeability will be measured on samples, which have undergone fracture damage due to loading at different fractions of the uniaxial compressive strength (e.g., 80%, 90% and 100%). The laboratory study will be complemented by an electrical resistivity survey of the dome structure (to be undertaken this coming February-March 2015). We will optically measure the density of fractures (i.e., spacing), and width. The resistivity study will be performed at different scales (1-200 metres) to assess the extent of fractures in individual blocks as well as through the entire dome and its underlying root. Mesoscale permeability measurements will be attempted by introducing salinated water into cracks on metre-size blocks whilst performing 3D electrical resistivity tomography. We aim to discuss

  18. Megacrystic pyroxene basalts sample deep crustal gabbroic cumulates beneath the Mount Taylor volcanic field, New Mexico

    NASA Astrophysics Data System (ADS)

    Schmidt, Mariek E.; Schrader, Christian M.; Crumpler, Larry S.; Rowe, Michael C.; Wolff, John A.; Boroughs, Scott P.

    2016-04-01

    Distributed over the ~ 2.3 m.y. history of the alkaline and compositionally diverse Mount Taylor Volcanic Field (MTVF), New Mexico is a widespread texturally distinct family of differentiated basalts that contain resorbed megacrysts (up to 3 cm) of plagioclase, clinopyroxene, and olivine ± Ti-magnetite ± ilmenite ± orthopyroxene. These lavas have gabbroic cumulate inclusions with mineral compositions similar to the megacrysts, suggesting a common origin. Gabbroic and megacrystic clinopyroxenes form positive linear arrays in TiO2 (0.2-2.3 wt.%) with respect to Al2O3 (0.7-9.3 wt.%). Plagioclase (An41-80) from representative thin sections analyzed for 87Sr/86Sr by laser ablation ICP-MS range from 0.7036 to 0.7048. The low 87Sr/86Sr plagioclases (0.7036 to 0.7037) are associated with high Ti-Al clinopyroxenes. Likewise, the higher 87Sr/86Sr plagioclases (0.7043 to 0.7047) are associated with the low-Al clinopyroxenes. Taken together, the pyroxene and plagioclase megacrysts appear to track the differentiation of a gabbroic pluton (or related plutons) from alkaline to Si-saturated conditions by fractional crystallization and crustal assimilation. Clinopyroxene-liquid geobarometry calculations suggest that crystallization occurred near the crust-mantle transition at an average of ~ 1200 °C and 12-13 kbar. The distribution of the megacrystic pyroxene basalts suggests that a gabbroic intrusive body underlies subregions of the MTVF that have generated silicic magmas. The gabbro is interpreted to be a significant heat and mass input into the lower crust that is capable of driving the petrogenesis of diverse silicic compositions (through fractionation and crustal assimilation), including mugearites, trachytes, trachy-andesites and dacites, high-Si rhyolites, and topaz rhyolites of the MTVF.

  19. Correlating field and laboratory rates of particle abrasion, Rio Medio, Sangre de Cristo Mountains, New Mexico

    NASA Astrophysics Data System (ADS)

    Polito, P. J.; Sklar, L. S.

    2006-12-01

    River bed sediments commonly fine downstream due to a combination of particle abrasion, selective transport of finer grains, and fining of the local sediment supply from hillslopes and tributaries. Particle abrasion rates can be directly measured in the laboratory using tumbling barrels and annular flumes, however, scaling experimental particle abrasion rates to the field has proven difficult due to the confounding effects of selective transport and local supply variations. Here we attempt to correlate laboratory and field rates of particle abrasion in a field setting where these confounding effects can be controlled. The Rio Medio, which flows westward from the crest of the Sangre de Cristo Mountains in north central New Mexico, is one of several streams studied by John P. Miller in the early 1960's. Several kilometers downstream of its headwaters, the river crosses the Picuris-Pecos fault. Upstream of the fault the river receives quartzite, sandstone and shale clasts from the Ortega Formation, while downstream sediments are supplied by the Embudo Granite. Because the upstream lithologies are not resupplied downstream of the fault, any observed fining of these clasts should be due only to abrasion and selective transport. We hypothesize that we can account for the effects of selective transport by comparing relative fining rates for the different upstream lithologies from both the field and a laboratory tumbler. By correlating laboratory abrasion rates with rock strength, we can predict the relative fining rates due solely to abrasion expected in the field; differences between the predicted and observed fining rates could then be attributed to selective transport. We used point counts to measure bed surface sediment grain size distributions at 15 locations along a 25 kilometer reach of the Rio Medio, beginning just downstream of the fault and ending upstream of a developed area with disturbed channel conditions. We recorded intermediate particle diameter as well

  20. Lahar simulation with SPH and field calibration at the Colima Volcano (Mexico)

    NASA Astrophysics Data System (ADS)

    Calvo, Leticia; Haddad, Bouchra; Capra, Lucia; Palacios, David

    2015-04-01

    As a result of the frequent effusive activity of Volcán de Colima (10° 30'44''N, 103° 37'02'' W), the most active volcano in Mexico, plenty of rain triggered lahars are produced, especially during the rainy season. Along the recent period of activity, particularly from 2010, many of these lahars channelled through the main ravines of the volcano and reach large distances, representing high risk for more than 10,000 people at the surroundings. Modeling of lahars has become an important tool in the assessment of the related hazards, in order to undertake appropriate mitigation actions and reduce the associated risks. Recent lahars at the Colima Volcano are well documented, so they can be used to prove the accuracy of modelling. In this work, we used the SPH (Smoothed Particle Hydrodynamics) method, a depth integrated coupled model created by Pastor in 2005, to replicate the propagation stage of 3 recent Colima lahars occurred on Montegrande ravine in 1992, 2011 and 2012. The studied events include hyperconcentrated, debris and a mixture of the previous flow natures. The inputs used for the SPH simulations were the initial point, volume of each lahar and an adapted morphology of its mass. Field data used to verify the SPH results include the stopping point of the lahar, its path, velocity and height values, as the floodplain area. All this information was a result of fieldwork recognition (cross section profiles of the inner part of the ravine) and free satellite imagery analysis. The best results were obtained using Bingham rheology. The proposed parameters to simulate Colima lahars were 20 Pa of yield strength and 30 Pa.s of viscosity for the 1992 lahar (hyperconcentrated flow), 200 Pa and 50 Pa.s in case of the 2011 debris flow, and finally 20 Pa and 24 Pa.s for the 2012 event, whose nature evolved from debris to an hyperconcentrated flow. In all cases a 1900 kg/m3 density was used. Highly accurate results showed the relevant role played by rheological

  1. The Taylor Creek Rhyolite of New Mexico: a rapidly emplaced field of lava domes and flows

    USGS Publications Warehouse

    Duffield, W.A.; Dalrymple, G.B.

    1990-01-01

    The Tertiary Taylor Creek Rhyolite of southwest New Mexico comprises at least 20 lava domes and flows. Each of the lavas was erupted from its own vent, and the vents are distributed throughout a 20 km by 50 km area. The volume of the rhyolite and genetically associated pyroclastic deposits is at least 100 km3 (denserock equivalent). The rhyolite contains 15%-35% quartz, sanidine, plagioclase, ??biotite, ??hornblende phenocrysts. Quartz and sanidine account for about 98% of the phenocrysts and are present in roughly equal amounts. With rare exceptions, the groundmass consists of intergrowths of fine-grained silica and alkali feldspar. Whole-rock major-element composition varies little, and the rhyolite is metaluminous to weakly peraluminous; mean SiO2 content is about 77.5??0.3%. Similarly, major-element compositions of the two feldsparphenocryst species also are nearly constant. However, whole-rock concentrations of some trace-elements vary as much as several hundred percent. Initial radiometric age determinations, all K-Ar and fission track, suggest that the rhyolite lava field grew during a period of at least 2 m.y. Subsequent 40Ar/39Ar ages indicate that the period of growth was no more than 100 000 years. The time-space-composition relations thus suggest that the Taylor Creek Rhyolite was erupted from a single magma reservoir whose average width was at least 30 km, comparable in size to several penecontemporaneous nearby calderas. However, this rhyolite apparently is not related to a caldera structure. Possibly, the Taylor Creek Phyolite magma body never became sufficiently volatile rich to produce a large-volume pyroclastic eruption and associated caldera collapse, but instead leaked repeatedly to feed many relatively small domes and flows. The new 40Ar/39Ar ages do not resolve preexisting unknown relative-age relations among the domes and flows of the lava field. Nonetheless, the indicated geologically brief period during which Taylor Creek Rhyolite magma was

  2. Megacrystic Clinopyroxene Basalts Sample A Deep Crustal Underplate To The Mount Taylor Volcanic Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Schmidt, M. E.; Schrader, C. M.; Crumpler, L. S.; Wolff, J. A.

    2012-12-01

    The alkaline and compositionally diverse (basanite to high-Si rhyolite) Mount Taylor Volcanic Field (MTVF), New Mexico comprises 4 regions that cover ~75 x 40 km2: (1) Mount Taylor, a large composite volcano and a surrounding field of basaltic vents; (2) Grants Ridge, constructed of topaz rhyolitic ignimbrite and coulees; (3) Mesa Chivato, a plateau of alkali basalts and mugearitic to trachytic domes; and (4) the Rio Puero basaltic necks. Distributed throughout its history (~3.6 to 1.26 Ma; Crumpler and Goff, 2012) and area (excepting Rio Puerco Necks) is a texturally distinct family of differentiated basalts (Mg# 43.2-53.4). These basalts contain resorbed and moth-eaten megacrysts (up to 2 cm) of plagioclase, clinopyroxene, and olivine ±Ti-magnetite ±ilmenite ±rare orthopyroxene. Some megacrystic lava flows have gabbroic cumulate inclusions with mineral compositions similar to the megacrysts, suggesting a common origin. For instance, gabbroic and megacrystic clinopyroxenes form linear positive arrays in TiO2 (0.2-2.3 wt%) with respect to Al2O3 (0.7-9.3 wt%). The lowest Al clinopyroxenes are found in a gabbroic inclusion and are associated with partially melted intercumulus orthopyroxene. Megacrystic and gabbroic plagioclase (An 41-80) in 4 representative thin sections were analyzed for 87Sr/86Sr by Laser Ablation ICP-MS. 87Sr/86Sr values for the suite range from 0.7036 to 0.7047. The low 87Sr/86Sr plagioclases (0.7036 to 0.7037) are associated with high Ti-Al clinopyroxenes. Likewise, the higher 87Sr/86Sr plagioclases (0.7043 to 0.7047) are associated with the low-Al clinopyroxenes. Taken together, these megacrysts track the differentiation of an intrusive body (or related bodies) from alkaline to Si-saturated conditions by fractional crystallization and crustal assimilation. The intrusive body likely underplates portions of the MTVF that have generated silicic magmas (Mount Taylor, Grants Ridge, Mesa Chivato). Although disequilibrium is implied by resorbed

  3. The Use of Geographic Information Technologies in Environmental Decision-Making in the State of Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Teodoro, Silva García José; Gustavo, Cruz Cárdenas; Salvador, Ochoa Estrada; Franciso, Estrada Godoy; Fabian, Villalpando Barragán

    2008-05-01

    One of the most urgent issues facing the human environment, a result of current human evolution is the increase in the production of Urban Solid Waste (USW). The State of Michoacán is no exception; the presence of waste facilities in the area is a very big problem and one with a strong geographical content (Mena et al., 2006). SIGs are one tool for addressing this kind of need. A model which has been commonly used for selecting areas for the final deposit of USW, and which has obtained good results, is so-called multicriterion decision-making. It has been applied in the context of integral USW management, and has generated both a methodology for the determination of safe places for final waste deposit and an Environmental Risk Index (ERI), which fulfills the requirements indicated by the Official Mexican Norm (NOM-083-SEMARNAT-2003). The methodology consists of a quadrant analysis of 25 ha of five factors. A rank was assigned to each of the factors, and this rank was standardized according to a scale from 0 to 10 and subsequently multiplied by a weight (W) which numerically represents the degree of importance and influence of each factor in the environment. Five represented the largest impact, and two represented the smallest impact. The ERI is the sum of the five factors considered and it is represented by means of the following equation: ERI = VVw+UsUsw+FrFrw+ln lnw+Zi Ziw, where ERI is the Environmental Risk Index, V Vw is the aquifer vulnerability, Us Usw represents the use of the soil, Fr Frw refers to the fracturing density, ln lnw represents the domain of the urban and industrial infrastructure, and Zi Ziw refers to flood zones. This was shown to be successful in different regions of Michoacán State, such as the Bajío area, the Paísde la Mariposa Monarca and Tierra Caliente. Another example is its application in the hydrogeologic context, which generated the Aquifer Veda index (a restriction diagram for the opening of new exploitations), and which is intended to regulate and give advice about the design of wells, their depth and optimum slot interval, their appropriate location and caudal, in those cases in which well-drilling is permitted. The above-mentioned approach is fundamental to the sustainable operating schemes for the handling of the underground water in the Ciénega de Chapala. This approach is intended to influence the scientific handling of the hydro resource, promoting sustainable politics and rules of operation.

  4. ADAPTIVE MANAGEMENT AND PLANNING MODELS FOR CULTURAL RESOURCES IN OIL & GAS FIELDS IN NEW MEXICO AND WYOMING

    SciTech Connect

    Peggy Robinson

    2005-07-01

    This report summarizes activities that have taken place in the last six (6) months (January 2005-June 2005) under the DOE-NETL cooperative agreement ''Adaptive Management and Planning Models for Cultural Resources in Oil and Gas Fields, New Mexico and Wyoming'' DE-FC26-02NT15445. This project examines the practices and results of cultural resource investigation and management in two different oil and gas producing areas of the United States: southeastern New Mexico and the Powder River Basin of Wyoming. The project evaluates how cultural resource investigations have been conducted in the past and considers how investigation and management could be pursued differently in the future. The study relies upon full database population for cultural resource inventories and resources and geomorphological studies. These are the basis for analysis of cultural resource occurrence, strategies for finding and evaluating cultural resources, and recommendations for future management practices. Activities can be summarized as occurring in either Wyoming or New Mexico. Gnomon as project lead, worked in both areas.

  5. The ~ 2000 yr BP Jumento volcano, one of the youngest edifices of the Chichinautzin Volcanic Field, Central Mexico

    NASA Astrophysics Data System (ADS)

    Arce, J. L.; Muñoz-Salinas, E.; Castillo, M.; Salinas, I.

    2015-12-01

    The Chichinautzin Volcanic Field is situated at the southern limit of the Basin of Mexico and the Metropolitan area of Mexico City, the third most populated city around the world. The Chichinautzin Volcanic field holds more than 220 monogenetic volcanoes. Xitle is the youngest of these with an estimated age of 1.6 ky BP. Xitle's eruptive activity took place during the Mesoamerican Mexican Pre-classic period and is related to the destruction of Cuicuilco Archaeological Site, the oldest civilization known in Central Mexico. However, there are still several regional cones that have not been dated. Based on 14C ages, stratigraphic and geomorphologic criteria, we conclude that the Jumento volcano, located to the west of Xitle, is one of the youngest cones of the Chichinautzin Volcanic Field. The Jumento volcano has a basaltic andesite composition, and its eruptive activity was initially hydromagmatic, followed by Strombolian and finally effusive events occurred recorded through: (1) a sequence of hydromagmatic pyroclastic surges and ashfall layers emplaced at a radius of > 5 km from the crater with charcoal fragments at its base; this activity built the Jumento's cone with slopes of 32°; and (2) lava flows that breached the southern part of the cone and flowed for up to 2.5 km from the vent. The resulting 14C ages for this volcano yielded a maximum age of 2 ky BP. Morphometric analysis indicates that the state of degradation of Jumento cone is similar to the Xitle, suggesting that the Jumento could be in the state of degradation of a volcanic structure of similar age or younger adding credence to the probable radiocarbon age of 2 ky BP for the Jumento edifice.

  6. Understanding High Temperature Gradients in the Buckman Well Field, Santa Fe County, New Mexico

    NASA Astrophysics Data System (ADS)

    Folsom, M.; Gulvin, C. J.; Tamakloe, F. M.; Yauk, K.; Kelley, S.; Frost, J.; Jiracek, G. R.

    2014-12-01

    We propose a conceptual model to explain elevated thermal gradients, localized laterally over a few 100 m, discovered during the SAGE program in 2013 and confirmed in 2014 at the Buckman water well field in the Española Basin of north central New Mexico. The anomalous gradients of temperature with depth, dT/dz, exceed 70 ºC/km and are found in three shallow (< 100 m-deep) USGS monitoring wells close to the Rio Grande. A temperature increase of only 3 - 4 ºC at ~100 m depth would elevate the regional temperature value enough to yield the anomalous dT/dz values in the upper ~100 m. The coincidence of a 25 km2 region of InSAR-confirmed subsidence with the locally anomalous dT/dz region suggests a way to achieve a higher temperature at ~ 100 m depth. The mechanism is an isothermal release of warmer water from ~ 200 m depth along a fissure or reactivated fault. A fourth well, 290 m away, has a temperature gradient of only 33ºC/km in the upper 100 m and a distinctly different geochemical profile, suggesting aquifer compartmentalization and possible faulting close to the anomaly. In 2001 a 800 m-long surface scarp with up to 0.2 m offset appeared 2 km to the east in response to over-pumping that depressed the groundwater table by over 100 m. Such drawdown is expected to have 2 - 5 m of compaction with attendant movement along faults or fissures. This could allow groundwater to be released upward isothermally until encountering an unbreached aquitard where it would establish an elevated thermal boundary. Besides the local thermal anomaly, we have temperature-logged deeper water wells in the area. These and other measurements have been used to construct cross-sections of isotherms across the Española Basin along the groundwater flow units (GFUs). This allows comparison of the local thermal anomaly with classic, regional, basin hydrological models. For example, the fully-screened Skillet well, 2.3 km from the anomaly, shows a classic concave down dT/dz form indicating

  7. Field Courses for Volcanic Hazards Mapping at Parícutinand Jorullo Volcanoes (Mexico)

    NASA Astrophysics Data System (ADS)

    Victoria Morales, A.; Delgado Granados, H.; Roberge, J.; Farraz Montes, I. A.; Linares López, C.

    2007-05-01

    During the last decades, Mexico has suffered several geologic phenomena-related disasters. The eruption of El Chichón volcano in 1982 killed >2000 people and left a large number of homeless populations and severe economic damages. The best way to avoid and mitigate disasters and their effects is by making geologic hazards maps. In volcanic areas these maps should show in a simplified fashion, but based on the largest geologic background possible, the probable (or likely) distribution in time and space of the products related to a variety of volcanic processes and events, according to likely magnitude scenarios documented on actual events at a particular volcano or a different one with similar features to the volcano used for calibration and weighing geologic background. Construction of hazards maps requires compilation and acquisition of a large amount of geological data in order to obtain the physical parameters needed to calibrate and perform controlled simulation of volcanic events under different magnitude-scenarios in order to establish forecasts. These forecasts are needed by the authorities to plan human settlements, infrastructure, and economic development. The problem is that needs are overwhelmingly faster than the adjustments of university programs to include courses. At the Earth Science División of the Faculty of Engineering at the Universidad Nacional Autónoma de México, the students have a good background that permits to learn the methodologies for hazards map construction but no courses on hazards evaluations. Therefore, under the support of the university's Program to Support Innovation and Improvement of Teaching (PAPIME, Programa de Apoyo para la Innovación y Mejoramiento de la Enseñanza) a series of field-based intensive courses allow the Earth science students to learn what kind of data to acquire, how to record, and process in order to carry out hazards evaluations. This training ends with hazards maps that can be used immediately by the

  8. Mexico's New Braceros: How NAFTA Promotes Child Labor and Truancy in the Onion Fields of Mexicali.

    ERIC Educational Resources Information Center

    Bacon, David

    1997-01-01

    Although NAFTA has proven profitable for U.S. growers who have relocated agricultural production to Mexico, it has helped create an economic crisis that has forced thousands of Mexican children to leave school in order to work and supplement their parents' shrinking income. In Mexicali Valley (Baja California), approximately a fourth of the…

  9. Field Characterization of Potential Reference Sediments in the Gulf of Mexico: Chemical and Biological Quality

    EPA Science Inventory

    Lewis, Michael A., Jed G. Campbell, Peggy S. Harris, Darrin D. Dantin, Steve S. Foss, Robert L. Quarles, James C. Moore and Cynthia A. Chancy. Submitted. Characterization of Potential Reference Areas in the Gulf of Mexico: Near-Coastal Sediment Chemical and Biological Quality. En...

  10. Field Characterization of Potential Reference Sediments in the Gulf of Mexico: Chemical and Biological Quality

    EPA Science Inventory

    Lewis, Michael A., Jed G. Campbell, Peggy S. Harris, Darrin D. Dantin, Steve S. Foss, Robert L. Quarles, James C. Moore and Cynthia A. Chancy. Submitted. Characterization of Potential Reference Areas in the Gulf of Mexico: Near-Coastal Sediment Chemical and Biological Quality. En...

  11. Field Response of Dendroctonus frontalis (Coleoptera: Scolytinae) to Synthetic Semiochemicals in Chiapas, Mexico.

    Treesearch

    Benjamin Moreno; Jorge Macias; Brian Sullivan; Stephen Clarke

    2008-01-01

    Dendroctonus frontalis Zimmermann (Coleoptera: Scolytinae) is the most serious pestof pines (Pinus spp.) in Mexico. ConspeciÞcs are attracted to trees undergoing colonization by the  aggregation pheromone frontalin, which is synergized by odors of pine oleoresin released from beetle-damaged host tissue. Synthetic racemic frontalin combined with turpentine has been the...

  12. Mexico's New Braceros: How NAFTA Promotes Child Labor and Truancy in the Onion Fields of Mexicali.

    ERIC Educational Resources Information Center

    Bacon, David

    1997-01-01

    Although NAFTA has proven profitable for U.S. growers who have relocated agricultural production to Mexico, it has helped create an economic crisis that has forced thousands of Mexican children to leave school in order to work and supplement their parents' shrinking income. In Mexicali Valley (Baja California), approximately a fourth of the…

  13. Field response of Dendroctonus frontalis (Coleoptera: Scolytinae) to Synthetic Semiochemicals in Chiapas, Mexico.

    Treesearch

    Benjamin Moreno; Jorge Macias; Brian T. Sullivan; Stephen R. Clarke

    2008-01-01

    Dendroctonus frontalis Zimmermann (Coleoptera: Scolytinae) is the most serious pest of pines (Pinus spp.) in Mexico. Con specifics are attracted to trees undergoing colonization by the aggregation pheromone frontalin, which is synergized by odors of pine oleoresin released from beetle-damaged host tissue. Synthetic racemic frontalin...

  14. Anomalously High Geothermal Gradients in the Buckman Well Field, Santa Fe County, New Mexico

    NASA Astrophysics Data System (ADS)

    Pollack, A.; Munda, R.; Farrell, T. F.; Kelley, S. A.; Frost, J.; Jiracek, G. R.

    2013-12-01

    Temperature as a function of depth was measured in ten wells in the Santa Fe, NM area as part of the Summer of Applied Geophysics Experience (SAGE) program. Eight of the wells are within 5.5 km of the city's Buckman municipal well field and two wells are at La Tierra, 16.5 km to the SE. Geothermal gradients increase from east to west towards the Buckman area, from 20°C/km at La Tierra to 76°C/km at Buckman. Within the Buckman well field, two wells on its eastern side were determined to have temperature gradients of 32°C/km and 42°C/km. Only 300 m west, the geothermal gradient sharply increases, and measured gradients reach 76 °C/km (well number SF4A), 62°C/km (SF4B), and 68°C/km (SF3A) in three shallow (<100 m) monitoring drill holes. Both local and regional causes may explain the geothermal anomaly. The short spatial wavelength of the horizontal gradient increase argues for a localized source. The unusually high gradients in three of the wells may be associated with fault-controlled, effective shallow-source, warm water upflow or with lateral flow in a shallow aquifer. On the regional level, the east to west increase in temperature gradients can be explained by deep circulating groundwater flow in the Espanola Basin and upwelling near the Rio Grande. Another possible explanation comes from gravity data gathered by SAGE over several years that shows a local NW-striking structural high in the area that could force localized convective upflow. Regional aeromag maps indicate magnetic lows exactly underneath the anomalous wells. These may be interpreted as buried volcanic plugs beneath the Buckman well field, acting as conduits for upwelling warmer waters. They may also indicate hydrothermally altered rock beneath the surface. A more nontraditional cause of the sharp thermal anomaly is also possible. The geothermal gradient anomaly coincides with the dramatic discovery by InSAR in 1993-2000 of localized ground subsidence due to excessive water well pumping

  15. Field guide to the continental Cretaceous-Tertiary boundary in the Raton basin, Colorado and New Mexico

    USGS Publications Warehouse

    Pillmore, C.L.; Nichols, D.J.; ,

    1999-01-01

    This guide consists of three general sections: an introduction that includes discussions of Raton basin stratigraphy and the Cretaceous Tertiary (K-T) boundary; descriptions of the geology along the route from Denver, Colorado, to Raton, New Mexico; and descriptions of several K-T sites in the Raton basin. Much of the information is from previous articles and field guides by the authors together with R. M. Flores and from road logs co-authored with Glenn R. Scott, both of the U.S.Geological Survey.

  16. Incidence of Plasmids in Marine Vibrio spp. Isolated from an Oil Field in the Northwestern Gulf of Mexico

    PubMed Central

    Hada, Howard S.; Sizemore, Ronald K.

    1981-01-01

    Presumptive marine Vibrio spp. were collected from an operational oil field and control site located in the northwestern Gulf of Mexico. Of 440 isolates analyzed for the presence of extrachromosomal deoxyribonucleic acid elements or plasmids by using the cleared lysate and agarose gel techniques, 31% showed distinct plasmid bands on agarose gels. A majority of the plasmids detected were estimated to have molecular masses of 10 × 106 or less. Multiple plasmids were observed in approximately half of the plasmid-containing strains. A number of isolates contained plasmids with similar banding and mobility patterns. The oil field area had noticeably more plasmid-containing strains (35 versus 23% in the control site) and a greater number of plasmids per plasmid-containing strain (an average of 2.5 plasmids, versus 1.5 in the control site). Oil field discharges might have resulted in increased plasmid incidence and diversity. Images PMID:16345685

  17. Geochemical model update of the Los Azufres, Mexico, geothermal reservoir

    SciTech Connect

    Hinojosa, E.T.

    1997-12-31

    Chemical and isotopic analyses of fluids produced by wells the Los Azuftes, Michoacan, geothermal field, have been studied to establish a geochemical model of the field. Water produced by the wells has a sodium-chloride composition characteristic of geothermal brine. This to be in equilibrium with the host rock at temperatures which vary from 280{degrees}C to 340{degrees}C. Based on steam data, the wells are producing from a liquid dominanted zone. The isotopic composition of the wells presents a shift with respect to meteoric line of {delta}{sup 18}O typical to fluids of geothermal origin which have equilibrated with rock at high temperatures.

  18. Real Time View of the Functions and Services of the Seismic Alert System of Mexico (SASMEX)

    NASA Astrophysics Data System (ADS)

    Espinosa Aranda, J.; Ibarrola Alvarez, G.; Cuellar Martinez, A.; Inostroza Puk, M.

    2013-05-01

    The Seismic Alert System of Mexico (SASMEX) is integrated since March 2012 by the Seismic Alert System of Mexico City (SAS), in continuous operation since 1991, and the Seismic Alert System of Oaxaca City (SASO) that started its services in 2003. SASMEX consists of 97 field seismic sensor station (FS) type triaxial accelerometer, mostly sponsored by the government of Mexico City and secondly by Oaxaca. The SASMEX covers the Pacific seismic hazard among the coast of Jalisco, Colima, Michoacan, Guerrero and Oaxaca; and the seismic region of Puebla and northern Oaxaca and Guerrero states. This integration lets to warn with better opportunity to the population of Mexico City, Oaxaca Oax., Acapulco Gro., Chilpancingo Gro. and recently Morelia Mich.; cities with a system called EASAS where receives seismic data from FS and emits earthquake early warning signals to the population. The recent sponsorship of Federal Government through the General Coordination of Civil Protection and the National Center for Disaster Prevention, reinforced integration SAS and SASO, and auspiced the development of a Real-Time Monitoring System of functions and services of SASMEX. This work show how is displayed the functions of services of SASMEX through this monitoring system and its possible application by Civil Protection authorities. This monitoring system can indicate the status of FS, the communications system and cities with EASAS. Additionally, when an earthquake occurs and is detected by the SASMEX, the monitoring system shows the messages of FS, whose consist in the characteristics of detection and seismic danger forecasted; in the case of a strong earthquake estimated by more than one FS, the EASAS of each city could automatically issue an Alert Public to its population. The monitoring system allows observing cities with EASAS that activate their alerts, displays a basic earthquake propagation model and how it reaches to other FS. Additionally, the monitoring system shows the

  19. Notes from the Field: Community-Based Prevention of Rocky Mountain Spotted Fever - Sonora, Mexico, 2016.

    PubMed

    Straily, Anne; Drexler, Naomi; Cruz-Loustaunau, Denica; Paddock, Christopher D; Alvarez-Hernandez, Gerardo

    2016-11-25

    Rocky Mountain spotted fever (RMSF), a life-threatening tickborne zoonosis caused by Rickettsia rickettsii, is a reemerging disease in Mexico (1,2). R. rickettsii is an intracellular bacterium that infects vascular endothelium and can cause multisystem organ failure and death in the absence of timely administration of a tetracycline-class antibiotic, typically doxycycline. Epidemic RMSF, as described in parts of Arizona and Mexico, is associated with massive local infestations of the brown dog tick (Rhiphicephalus sanguineus sensu lato) on domestic dogs and in peridomestic settings that result in high rates of human exposure; for example, during 2003-2012, in Arizona the incidence of RMSF in the three most highly affected communities was 150 times the U.S. national average (3,4). In 2015, the Mexico Ministry of Health (MOH) declared an epidemiologic emergency because of high and sustained rates of RMSF in several states in northern Mexico, including the state of Sonora. During 2004-2015, a total of 1,129 cases and 188 RMSF deaths were reported from Sonora (Sonora MOH, unpublished data, 2016). During 2009-2015, one impoverished community (community A) in Sonora reported 56 cases of RMSF involving children and adolescents, with a case-fatality rate of 40% (Sonora MOH, unpublished data, 2016). Poverty and lack of timely access to health services are risk factors for severe RMSF. Children are especially vulnerable to infection, because they might have increased contact with dogs and spend more time playing around spaces where ticks survive (5). In Sonora, case fatality rates for children aged <10 years can be as high as 30%, which is almost four times the aggregate case-fatality rate reported for the general population of the state (8%) (2), and 10-13 times higher than the case-fatality rate described for this age group in the United States (2.4%) (6).

  20. A statistical description of the velocity fields from upper ocean drifters in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    DiMarco, Steven F.; Nowlin, Worth D., Jr.; Reid, R. O.

    We analyzed 1397 drifter records collected in the Gulf of Mexico and northwestern Cayman Basin between the years 1989 and 1999 to describe the general features of the upper ocean circulation. These drifters were generally drogued at 50 m below the surface and exclude those of the Surface CUrrent Lagrangian Program (SCULP). In addition to the dominant flows through the Yucatan Channel and Straits of Florida, robust circulation features clearly seen include: a weak cyclone south of 21°N in the Bay of Campeche, westward zonal flow across the Gulf between 21°N and 24°N, a northward western boundary current between 95°W and 97°W and 24°N and 26°N, mean downcoast (westward) flow on the Texas-Louisiana shelf, highly variable mean flow on the shelves and slope of the northeastern Gulf, mean upcoast (southward) flow on the lower West Florida Shelf, and a large region of high variability in the deep regions of the central Gulf of Mexico. Although much of the driving of the Gulf of Mexico is attributed to currents associated with the Loop Current and its associated Loop Current Eddies (particularly in the deep waters), other features can be directly correlated with seasonal wind driving, particularly on the shelves of the northern Gulf, near the western boundary, and in the Bay of Campeche.

  1. Mexican Seismic Alert System's SAS-I algorithm review considering strong earthquakes felt in Mexico City since 1985

    NASA Astrophysics Data System (ADS)

    Cuellar Martinez, A.; Espinosa Aranda, J.; Suarez, G.; Ibarrola Alvarez, G.; Ramos Perez, S.; Camarillo Barranco, L.

    2013-05-01

    The Seismic Alert System of Mexico (SASMEX) uses three algorithms for alert activation that involve the distance between the seismic sensing field station (FS) and the city to be alerted; and the forecast for earthquake early warning activation in the cities integrated to the system, for example in Mexico City, the earthquakes occurred with the highest accelerations, were originated in the Pacific Ocean coast, whose distance this seismic region and the city, favors the use of algorithm called Algorithm SAS-I. This algorithm, without significant changes since its beginning in 1991, employs the data that generate one or more FS during P wave detection until S wave detection plus a period equal to the time employed to detect these phases; that is the double S-P time, called 2*(S-P). In this interval, the algorithm performs an integration process of quadratic samples from FS which uses a triaxial accelerometer to get two parameters: amplitude and growth rate measured until 2*(S-P) time. The parameters in SAS-I are used in a Magnitude classifier model, which was made from Guerrero Coast earthquakes time series, with reference to Mb magnitude mainly. This algorithm activates a Public or Preventive Alert if the model predicts whether Strong or Moderate earthquake. The SAS-I algorithm has been operating for over 23 years in the subduction zone of the Pacific Coast of Mexico, initially in Guerrero and followed by Oaxaca; and since March 2012 in the seismic region of Pacific covering the coasts among Jalisco, Colima, Michoacan, Guerrero and Oaxaca, where this algorithm has issued 16 Public Alert and 62 Preventive Alerts to the Mexico City where its soil conditions increase damages by earthquake such as the occurred in September 1985. This work shows the review of the SAS-I algorithm and possible alerts that it could generate from major earthquakes recordings detected by FS or seismometers near the earthquakes, coming from Pacific Ocean Coast whose have been felt in Mexico

  2. Small scale field trials of Bacillus sphaericus (strain 2362) against anopheline and culicine mosquito larvae in southern Mexico.

    PubMed

    Arredondo-Jiménez, J I; López, T; Rodríguez, M H; Bown, D N

    1990-06-01

    Experimental breeding sites simulating natural conditions were used to evaluate the efficacy of 2 formulations of Bacillus sphaericus (strain 2362) against Anopheles albimanus and culicine (mostly Culex coronator and Cx. quinquefasciatus) mosquito larvae of southern Mexico. Three doses of each formulation were used in a first field trial: 2, 3 and 4 g/m2 (granular) or 2, 3 and 4 ml/m2 (liquid); and in a second field trial: 0.125, 0.24 and 0.5 g/m2 (granular) or 0.125, 0.25 and 0.5 ml/m2 (liquid). The optimum concentrations of each formulation for effective control of larval populations over periods of 3-4 months were 0.125 ml/m2 of liquid product for Culex spp. and 2 g/m2 of granular product for An. albimanus (ca. 70% mean reduction).

  3. [Territorial mobility in medical education in Mexico].

    PubMed

    Márquez-Serrano, M; Vázquez-Martínez, D; García-Molina, C

    1996-01-01

    This work aimed to determine the migration patterns of medical students within Mexico. We obtained the places of origin of graduates and the states where they registered their medical degrees at the Ministry of Education General Registry of Professions (SEP), between 1970-1974, 1980-1984 and 1985-1989. Data were organized as follows: Attracting foci, sending foci, transition foci, and important migrant flows. The concentration of medical human resource development, is reflected by the existence of a few attracting foci (D.F., Jalisco, Nuevo Leon, and to a less extent, Puebla and Michoacan). Also, we observed the persistence of traditional sending foci (Guanajuato, Chiapas, Colima, Campeche). However, some important changes occurred throughout the study period, namely, a decrease of the migratory mobility of university students. During 1970-1974, almost half of them (47%) obtained their degrees outside their place of origin; during 1980-1984 this figure decreased to 34% and during 1985-1989, it decreased further to 30.6%. Second, the participation of D.F. as a main human resource development center diminished; from 59% to 40% during 1970-1974, it went down, to 30% in the following quinquennium, while it increased in Jalisco, Michoacan and Nuevo Leon. The establishment of medical schools in almost every Mexican state has had a central role in the migration patterns of medical students. Nevertheless, our results show that there are other reasons accounting for the persistence of the concentration of medical human resources development in main cities of the nation such as Guadalajara and Monterrey.

  4. Recent SO2 camera and OP-FTIR field measurements in Mexico and Guatemala

    NASA Astrophysics Data System (ADS)

    La Spina, Alessandro; Salerno, Giuseppe; Burton, Michael

    2013-04-01

    Between 22 and 30 November 2012 a field campaign was carried out at Mexico and Guatemala with the objectives of state the volcanic gas composition and flux fingerprints of Popocatepetl, Santiaguito, Fuego and Pacaya by exploiting simultaneously UV-camera and FTIR measurements. Gases were measured remotely using instruments sensitive to ultraviolet and infrared radiation (UV spectrometer, SO2-camera and OP-FTIR). Data collection depended on the requirements of the methodology, weather condition and eruptive stage of the volcanoes. OP-FTIR measurements were carried out using the MIDAC interferometer with 0.5 cm-1 resolution. Spectra were collected in solar occultation mode in which the Sun acts as an infrared source and the volcanic plume is interposed between the Sun and the spectrometer. At Santiaguito spectra were also collected in passive mode using the lava flow as a radiation source. The SO2-camera used for this study was a dual camera system consisting of two QS Imaging 640s cameras. Each of the two cameras was outfitted with two quartz 25mm lens, coupled with two band-pass filters centred at 310nm and at 330nm. The imaging system was managed by a custom-made software developed in LabView. The UV-camera system was coupled with a USB2000+ spectrometer connected to a QP1000-2-SR 1000 micron optical fiber with a 74-UV collimating lens. For calibration of plume imagery, images of five quartz cells containing known concentration path-lengths of SO2 were taken at the end of each sampling. Between 22 and 23 November 2012 UV-camera and FTIR observations were carried out at Popocatepetl. During the time of our observation, the volcano was characterised by pulsing degassing from the summit crater forming a whitish plume that dispersed rapidly in the atmosphere according to wind direction and speed. Data were collected from the Observatorio Atmosférico Altzomoni (Universidad Nacional Autónoma de México) at 4000 metre a.s.l. and at a distance of ~12 km from the volcano

  5. Field studies of engineered barriers for closure of low level radioactive waste landfills at Los Alamos, New Mexico, USA

    SciTech Connect

    Nyhan, J.W.; Langhorst, G.J.; Martin, C.E.; Martinez, J.L.; Schofield, T.G.

    1993-05-01

    The Los Alamos National Laboratory examined water balance relationships for four different landfill cover designs containing engineered barriers. These field experiments were performed at Los Alamos, New Mexico, USA, in 1.0- by 10.0-m plots with downhill slopes of 5, 10, 15, and 25%. Field measurements of seepage, precipitation, interflow, runoff, and soil water content were collected in each of the 16 plots representing four slopes each with four cover designs: Conventional, EPA, Loam Capillary Barrier and Clay Loam Capillary Barrier. A seepage collection system was installed beneath each cover design to evaluate the influence of slope length on seepage using a series of four metal pans filled with medium gravel that were placed end-to-end in the bottom of each field plot. An automated water flow data logging system was used to collect hourly seepage, interflow and runoff data and consisted of 100 100-liter tanks, each of which was equipped with an ultrasonic liquid-level sensor and a motor-operated ball valve used to drain the tank. Soil water content was routinely monitored every six hours at each of 212 locations throughout the 16 plots with time domain reflectrometry (TDR) techniques using an automated and multiplexed measurement system. Field data is presented to show the effects of slope and slope length on the performance of each landfill cover design for the first 15 months of this field experiment.

  6. Vertical profiles of ozone, VOCs and meteorological parameters in within and outside of Mexico City during the MILAGRO field Campaign

    NASA Astrophysics Data System (ADS)

    Marquez, C.; Greenberg, J.; Bueno, E.; Bernabe, R.; Aguilar, J.; Blanco, S.; Wöhrnschimmel, H.; Guenther, A.; Cardenas, B.; Turnipseed, A.

    2007-05-01

    High ozone levels with maxima over 250 ppb have been an air quality problem in Mexico City for more than a decade. This ozone is produced in the daytime by photochemical reactions, initiated by its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of solar ultraviolet radiation. The objective of this work is to contribute to the understanding of the evolution of these air pollutants at different heights of the boundary layer by means of vertical profile measurements. Ozone, VOCs and meteorological vertical profiles were determined in Northern Mexico City (T0 site) using a tethered balloon for 10 days during the MILAGRO field Campaign 2006, between 4 AM and 4 PM. Measurements were done up to 1000 meter above ground (ozone and meteorological parameters) and up to 200 m above ground for VOCs. VOCs samples were collected during 4 minutes in canisters and analyzed with GC-FID to identify 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane and o-xylene). For 4 of the days, VOC integrated samples were also taken using personal pumps and absorbent cartridges at height between 200 and 1000 m. Sample cartridges were analyzed by GC-MS for volatile organic compounds (n-butane, i-pentane, n- pentane, benzene, toluene, ethyl-benzene, o-xylene, m&p-xylene, 1,2,4-tri-methyl-benzene and C3-benzenes). Ozone vertical profiles, frequently presented high concentrations above 400 m in the early morning. During the daytime, more homogeneous profiles indicate an increased vertical mixing. VOCs profiles show similar concentrations for all heights at dawn. In the morning, highest concentrations were determined at a height of about 100 meter, whereas at noon and in the afternoon concentrations decreased with height. Comparing VOC concentrations during the course of a day, highest values are measured in the morning. The highest VOC concentrations were propane, butane, and toluene. For some

  7. NOAA Ship Okeanos Explorer 2012 Field Season in the Northern Gulf of Mexico and U.S. Atlantic Continental Margin

    NASA Astrophysics Data System (ADS)

    Skarke, A. D.; Lobecker, E.; Malik, M.; VerPlanck, N.

    2012-12-01

    The NOAA Ship Okeanos Explorer, jointly operated by the NOAA Office of Ocean Exploration and Research and the NOAA Office of Marine and Aviation Operations, is America's only federally managed ship dedicated solely to ocean exploration. The 2012 field season was spent exploring the northern Gulf of Mexico and the U.S. Atlantic continental shelf break and slope. In the Gulf of Mexico, mapping and remotely operated vehicle operations focused on the salt domes and canyons offshore Mississippi and Louisiana, and characterized several of the hundreds of seeps that were detected in the water column backscatter data collected with the ship's Kongsberg EM 302 multibeam sonar (30 kHz) during the 2011 field season. A team of NOAA and non-NOAA partners identified priority frontier areas along the continental shelf and slope between North Carolina and Cape Cod, mapping numerous canyons selected for focused mapping exploration in partnership with the North East Fisheries Science Center, the Mid-Atlantic Regional Council on the Ocean (a state level partnership between various states including NY, NJ, DE, MD, and VA), Woods Hole Oceanographic Institution (WHOI) and Virginia Sea Grant. The 2012 mapping efforts built on data collected during the 2011 field season. Okeanos Explorer data were leveraged by NOAA Ship Henry B. Bigelow to conduct towed camera operations to ground truth multibeam backscatter data for deepwater coral habitat assessment. The Blake Ridge and Cape Fear Diapirs offshore North Carolina were a third focus of exploration operations. Seven 900 meter high cold seeps were discovered in the diapir province. Exploration incorporated WHOI's Sentry autonomous underwater vehicle and its full suite of mapping and oceanographic sensors were used to characterize six seep sites. All data collected by Okeanos Explorer are available via the NOAA public archives with metadata records within 60 to 90 days of the end of each cruise.

  8. Analysis of long-term land subsidence near Mexico City: Field investigations and predictive modeling

    NASA Astrophysics Data System (ADS)

    Ortega-Guerrero, Adrian; Rudolph, David L.; Cherry, John A.

    1999-11-01

    The Mexico City region has several flat plains formed on exceptionally porous (60-90%) lacustrine deposits overlying a highly productive regional aquifer. Severe land subsidence due to consolidation of the lacustrine aquitard caused by aquifer exploitation has resulted in restrictions on pumping in the core of Mexico City. This has led to large increases in aquifer pumping in the outlying lacustrine plains where satellite communities are rapidly expanding. The Chalco Basin is one of these lacustrine areas where pumping began in the 1950s and greatly increased in the 1980s. The lacustrine sequence in the Chalco area is significantly thicker than anywhere else in the Basin of Mexico averaging 100 m and reaching a maximum thickness of 300 m. Consequently, this area is susceptible to the highest potential land subsidence effects as a result of groundwater extraction of anywhere in the basin. Land subsidence in the central part of the Chalco Basin has increased to 0.4 m/yr since 1984 and by 1991 total subsidence had reached 8 m. The rapid land subsidence in this area is causing the accumulation of meteoric waters during the rainy season resulting in extensive flooding of farmland. This study first demonstrates a methodology for combining hydraulic data from a network of monitoring wells, geotechnical data from core samples, and a compilation of historical information on land surface elevation to quantify groundwater flow and land subsidence phenomena within the rapidly subsiding Chalco Basin. Then a one-dimensional mathematical model is employed to develop predictions of future land subsidence under a range of pumping conditions. The model permits the hydraulic properties of the aquitard to vary as transient functions of hydraulic head and porosity. Simulations suggest that under current pumping rates, total land subsidence in the area of thickest lacustrine sediment will reach 15 m by the year 2010. If pumping is reduced to the extent that further decline in the

  9. Long-term BVRI light curves of 5 pre-main sequence stars in the field of "Gulf of Mexico"

    NASA Astrophysics Data System (ADS)

    Ibryamov, Sunay I.; Semkov, Evgeni H.; Peneva, Stoyanka P.

    2015-01-01

    We present new data from BVRI photometric observations of five PMS stars during the period from April 2013 to July 2014. The stars are located in the field of NGC 7000/IC 5070 ("Gulf of Mexico") -- a region with active star formation. The presented paper is a continuation of our long-term photometric investigations of the young stellar objects in this region. The long-term multicolor photometric observations of PMS stars are very important for their exact classification. Our results show that the studied stars exhibit different types of photometric variability in all bands. We tried to classify them using our data from the long-term photometry and data published by other authors.

  10. Statistical properties of the surface velocity field in the northern Gulf of Mexico sampled by GLAD drifters

    NASA Astrophysics Data System (ADS)

    Mariano, A. J.; Ryan, E. H.; Huntley, H. S.; Laurindo, L. C.; Coelho, E.; Griffa, A.; Özgökmen, T. M.; Berta, M.; Bogucki, D.; Chen, S. S.; Curcic, M.; Drouin, K. L.; Gough, M.; Haus, B. K.; Haza, A. C.; Hogan, P.; Iskandarani, M.; Jacobs, G.; Kirwan, A. D.; Laxague, N.; Lipphardt, B.; Magaldi, M. G.; Novelli, G.; Reniers, A.; Restrepo, J. M.; Smith, C.; Valle-Levinson, A.; Wei, M.

    2016-07-01

    The Grand LAgrangian Deployment (GLAD) used multiscale sampling and GPS technology to observe time series of drifter positions with initial drifter separation of O(100 m) to O(10 km), and nominal 5 min sampling, during the summer and fall of 2012 in the northern Gulf of Mexico. Histograms of the velocity field and its statistical parameters are non-Gaussian; most are multimodal. The dominant periods for the surface velocity field are 1-2 days due to inertial oscillations, tides, and the sea breeze; 5-6 days due to wind forcing and submesoscale eddies; 9-10 days and two weeks or longer periods due to wind forcing and mesoscale variability, including the period of eddy rotation. The temporal e-folding scales of a fitted drifter velocity autocorrelation function are bimodal with time scales, 0.25-0.50 days and 0.9-1.4 days, and are the same order as the temporal e-folding scales of observed winds from nearby moored National Data Buoy Center stations. The Lagrangian integral time scales increase from coastal values of 8 h to offshore values of approximately 2 days with peak values of 3-4 days. The velocity variance is large, O>(1>) m2/s2, the surface velocity statistics are more anisotropic, and increased dispersion is observed at flow bifurcations. Horizontal diffusivity estimates are O>(103>) m2/s in coastal regions with weaker flow to O>(105>) m2/s in flow bifurcations, a strong jet, and during the passage of Hurricane Isaac. The Gulf of Mexico surface velocity statistics sampled by the GLAD drifters are a strong function of the feature sampled, topography, and wind forcing.

  11. The groundwater regime of the Valley of Mexico from historic evidence and field observations

    NASA Astrophysics Data System (ADS)

    Durazo, Jaime; Farvolden, R. N.

    1989-12-01

    Groundwater is a matter of major importance in the Valley of Mexico because some 20 million people depend on it for most of their water supply. In Mexico, historical accounts, documents and native legends provide additional information of past conditions which relates to hydrogeological conditions. In any analysis of groundwater resources it is important to know the original conditions. The Valley of Mexico is a graben structure, closed hydrologically and covered by a series of lakes at the time of the Conquest. Groundwater recharge occurs in the mountains of volcanic rocks that surround the Valley to form the Basin of Mexico. Where the rocks are visibly permeable, the water-table is deep, for the most part, and runoff is low. Thick lacustrine clays cover the Valley floor and artesian conditions once prevailed. Large springs of potable water were numerous at the edge of the Valley, and where permeable aquifers pinch-out. Thermal mineral springs occur along lineaments thought to be fractures in the rocks below the alluvial fill. The entire Valley floor and the lowest slopes of the mountains were zones of groundwater discharge. All water discharge from the Valley was by evaporation and transpiration, and salts accumulated in the lake-water and in the clays. The main lakes were nonpotable and the Aztecs and later the Spanish colonials depended on groundwater from the springs. Salt production from brines was an important industry in the Aztec society as it is today. The ahuehuete tree, ( taxodium mucronatum), which commonly lives to be many hundreds of years old, is a phreatophyte and an indicator of fresh groundwater discharge in the Valley. It used to be much more abundant. Its occurence where earthquake damage is worst suggests upward migration of fresh groundwater through fractures in the clay tht have been opened by seismic response. The water table and the capillary fringe are near ground surface over a wide zone of lowlands around the edge of the ancient lakes

  12. Development history of deep water Plio-Pleistocene sands in the East Breaks 165 field, Gulf of Mexico

    SciTech Connect

    Bernaski, G.; Guderjahn, C.G. )

    1991-03-01

    The stratigraphic complexity of the Plio-Pleistocene reservoir sands in the East Breaks 165 field (offshore Texas) is readily demonstrated after the completion of exploration and development involved: (1) prediction of turbidite sand facies distributions and thickness, and (2) identification of fault offsets in the high variable reservoir sands. The well control and a 3D seismic data set provide the basis for reservoir description and a deepwater sand depositional model in the East Breaks 165 area. Four main productive sand intervals are present in the Plio-Pleistocene section. All are characterized by rapid lateral thickness and facies and fining-upward channel levee/overbank facies. The channel systems developed within an intraslope basin. The main reservoir structure is a highly faulted anticline located downthrown to northeast-trending extensional faults with up to 2,500 feet of displacement. The faulting is result of structural collapse owing to salt withdrawal from a salt-cored anticlinal ridge. Numerous small-scale faults that juxtapose permeable and impermeable units have added further complexity to the field development. The refined turbidite channel and channel levee/overbank model has been important in delineating future recompletion and development targets in the East Breaks 165 field. This model should also prove to be a useful analog for future Gulf of Mexico deepwater exploration and development programs.

  13. Morphometric characterization of monogenetic volcanic cones of the Chichinautzin and Michoacán-Guanajuato monogenetic volcanic fields in Mexico

    NASA Astrophysics Data System (ADS)

    Zarazua-Carbajal, Maria Cristina; De la Cruz-Reyna, Servando; Mendoza-Rosas, Ana Teresa

    2014-05-01

    Morphometric characterization of volcanic edifices is one of the main approaches providing information about a volcano eruptive history, whether it has one or more eruptive vents or if it had any sector collapses. It also provides essential information about the physical processes that modify their shapes during periods of quietness, and quite significantly, about the volcanoes' ages. In the case of monogenetic activity, a volcanic field can be characterized by the size and slope distributions, and other cone's morphometric parameter distributions that may provide valuable information about the temporal evolution of the volcanic field. The increasingly available high-resolution digital elevation models and the continuously developing computer tools have allowed a faster development and more detailed morphometric characterization techniques. We present here a methodology to readily obtain diverse volcanic cone shape parameters from the contour curves such as mean slope, slope distribution, dimensions of the cone and crater, crater location within the cone, orientation of the cone's principal axis, eccentricity, and other morphological features using an analysis algorithm that we developed, programmed in Python and ArcPy. Preliminary results from the implementation of this methodology to the Chichinautzin and Michoacán-Guanajuato monogenetic volcanic fields in Mexico have permitted a preliminary estimation of the age distribution of some of the cones with an acceptable correlation with the available radiometric ages. A large part of the Chichinautzin region DEM was obtained from a LIDAR survey by the Mexican National Institute of Statistics and Geography (INEGI).

  14. Preliminary Studies of the Reservoir Capacity and the Generating Potential of the Baca Geothermal Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Bodvarsson, G. S.; Haar, S. Vonder; Wilt, M.; Tsang, C. F.

    1982-12-01

    A 50-MWe geothermal power plant is being considered for the Baca site in the Valleys Caldera, New Mexico, as a joint venture of the Department of Energy (DOE) and Union Oil Company of California. To date, over 20 wells have been drilled on the prospect, and the data from these wells indicate the presence of a high-temperature, liquid-dominated reservoir. In this paper, data from the open literature on the physical characteristics of the field are used to estimate the amount of hot water in place (reservoir capacity) and the length of time the reservoir can supply steam for a 50-MWe power plant (reservoir longevity). The reservoir capacity is estimated to be 1012 kg of hot fluid by volumetric calculations using existing geological, geophysical, and well data. The criteria used are described and the sensitivity of the results discussed. The longevity of the field is studied using a two-phase numerical simulator (SHAFT79). A number of cases are simulated based upon different boundary conditions and upon injection and production criteria. The results obtained from the simulation studies indicate that it is questionable that the Baca field can supply enough steam for a 50-MWe power plant for 30 years. Although the estimated reservoir reserves greatly exceed those needed for a 50-MWe power plant, the low transmissivity of the reservoir would cause localized boiling and rapid pressure decline during exploitation. It is therefore apparent that the conventional zero-dimensional (lumped parameter models) cannot be used to evaluate the generating capacities of low-permeability fields such as the Baca field.

  15. Successional trends in Sonoran Desert abandoned agricultural fields in northern Mexico

    USGS Publications Warehouse

    Castellanos, A.E.; Martinez, M.J.; Llano, J.M.; Halvorson, W.L.; Espiricueta, M.; Espejel, I.

    2005-01-01

    Excessive ground-water use and saline intrusion to the aquifer led, in less than three decades, to an increase in abandoned agricultural fields at La Costa de Hermosillo, within the Sonoran Desert. Using a chronosequence from years since abandonment, patterns of field succession were developed. Contrary to most desert literature, species replacement was found, both in fields with and without saline intrusion. Seasonal photosynthetic capacity as well as water and nitrogen use efficiencies were different in dominant early and late successional plant species. These ecological findings provided a framework for a general explanation of species dominance and replacement within abandoned agricultural fields in the Sonoran Desert. ?? 2004 Elsevier Ltd. All rights reserved.

  16. Assessing the local wind field at Sierra Grande Mountain in New Mexico with instrumentation

    SciTech Connect

    Barnett, K.M.; Reynolds, R.D.

    1981-05-01

    Six systems were installed on top of Sierra Grande, a nearly symmetrical mountain in New Mexico about halfway between Raton and Clayton, with a peak of 2659 m (8720 ft msl) standing over a wide mesa of approximately 1829 m (6000 ft msl). Two systems were on the peak, one at 10 m (33 ft) above the surface and the other at 20 m (66 ft) because the peak is often the most probable spot for the greatest wind energy. The two levels were needed to measure variations of speed with height. Four other systems with instruments at 10-m (33 ft) were located roughly north, east, south, and west from the center on secondary ridge lines to measure certain horizontal variations of the wind. The wind direction and speed were measured every 6 minutes, a time interval considerably shorter than the traditional 1 hour but long enough so that all WECS power outputs are expected to respond to these wind speed variations. All six systems were operated for a period of six months between 6 June 1979-5 December 1979.

  17. Application of microbial source tracking methods in a Gulf of Mexico field setting.

    PubMed

    Korajkic, A; Badgley, B D; Brownell, M J; Harwood, V J

    2009-11-01

    Microbial water quality and possible human sources of faecal pollution were assessed in a Florida estuary that serves shellfishing and recreational activities. Indicator organisms (IO), including faecal coliforms, Escherichia coli and enterococci, were quantified from marine and river waters, sediments and oysters. Florida recreational water standards were infrequently exceeded (6-10% of samples); however, shellfishing standards were more frequently exceeded (28%). IO concentrations in oysters and overlaying waters were significantly correlated, but oyster and sediment IO concentrations were uncorrelated. The human-associated esp gene of Enterococcus faecium was detected in marine and fresh waters at sites with suspected human sewage contamination. Lagrangian drifters, used to determine the pathways of bacterial transport and deposition, suggested that sediment deposition from the Ochlockonee River contributes to frequent detection of esp at a Gulf of Mexico beach. These data indicate that human faecal pollution affects water quality in Wakulla County and that local topography and hydrology play a role in bacterial transport and deposition. A combination of IO enumeration, microbial source tracking methods and regional hydrological study can reliably inform regulatory agencies of IO sources, improving risk assessment and pollution mitigation in impaired waters.

  18. Characterization of a 21-Story Reinforced Building in the Valley of Mexico Using MEMS Accelerometers.

    NASA Astrophysics Data System (ADS)

    Husker, A. L.; Dominguez, L. A.; Becerril, A.; Espejo, L.; Cochran, E. S.

    2014-12-01

    Low cost MEMS accelerometers are becoming increasingly higher resolution making them useful in strong motion studies. Here we present a building response analysis in the lakebed zone of the Valley of Mexico. The Valley of Mexico represents one of the highest seismic risk locations in the world and incorporates Mexico City and part of Mexico State. More than 20 million people live there and it is the political and economic center of Mexico. In addition the valley has very high site effects with amplifications 100 - 500 times that of sites outside of the basin (Singh et al., 1988; Singh et al., 1995). We instrumented a 21-story building with MEMS accelerometers as part of the Quake Catcher Network or Red Atrapa Sismos as it is called in Mexico. The building known as the Centro Cultural de Tlateloco is located in an important historical and political area as well as a zone with some of the highest amplifications in the Valley of Mexico that had some of the worst destruction after the 1985 M8.1 Michoacan earthquake. During the earthquake most of the buildings that failed were between 7 - 18 stories tall. The peak accelerations near Tlateloco were at periods of 2 seconds. Since the earthquake the building has been retrofitted with N-S crossing supports to help withstand another earthquake. We present the measurements of frequencies and amplifications between floors for the length of the building.

  19. Paleomagnetism in the Determination of the Emplacement Temperature of Cerro Colorado Tuff Cone, El Pinacate Volcanic Field, Sonora, Mexico.

    NASA Astrophysics Data System (ADS)

    Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Vidal Solano, J. R.; Garcia Amador, B.; Gonzalez-Rangel, J. A.

    2014-12-01

    Cerro Colorado Maar is located at the World Heritage Site, biosphere reserve El Pinacate and Gran Desierto del Altar, at the NNW region of Sonora, Mexico (in El Pinacate Volcanic Field). It is a tuff cone, about 1 km diameter, result of several phreatomagmatic episodes during the late Quaternary. We report paleomagnetic and rock magnetic properties from fusiform volcanic bombs obtained from the borders of Cerro Colorado. This study is based in the thermoremanent magnetization TRM normally acquired by volcanic rocks, which can be used to estimate the emplacement temperature range. We performed the experiments on 20 lithic fragments (10 cm to 20 cm approximately), taking 6-8 paleomagnetic cores from each. Rock magnetic experiments (magnetic susceptibility vs. temperature (k-T), hysteresis curves and FORC analysis, shows that the main magnetic mineral carriers of magnetization are titanomagnetite and titanohematite in different levels of intergrowth. The k-T curves suggest in many cases, only one magnetic phase, but also in other cases a second magnetic phase. Thermal demagnetization was used to demagnetize the specimens in detailed short steps and make a well-defined emplacement temperature determination ranges. We found that temperature emplacement determination range for these two magnetic phases is between 350-450 °C, and 550-580 °C, respectively. These results are consistent with those expected in an eruption of Surtsey type, showing a distinct volcanic activity compared to the other craters from El Pinacate volcanic field.

  20. Comprehensive Paleomagnetic Study of the Oligocene-Miocene Rocks from the San Luis Potosí Volcanic Field, Mexico

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Gonzalez-Rangel, J. A.; Torres-Hernandez, J. R.

    2014-12-01

    Comprehensive paleomagnetic study of the Oligocene-Miocene sequence of lithological units from the San Luis Potosí volcanic field in central Mexico was accomplished to set up the magnetostratigraphic record. Two hundred and one oriented standard paleomagnetic cores corresponding to twenty-eight paleomagnetic sites were collected from all units. Rock-magnetic properties are characteristic for each unit. Isothermal remanent magnetization acquisition curves and continuous susceptibility vs. temperature experiments point from low to medium-Ti content in titanomagnetite as the main opaque magnetic minerals, presumably result from oxy-exsolution processes during the initial flow cooling. Opaque mineral microscopy supports this assumption. Unblocking temperature and hysteresis parameters suggests predominance of pseudo-single domain magnetic grain size. Thermal and alternating field demagnetizations show mostly well-defined univectorial magnetizations. Most sites present a mean direction with small angular dispersion. The overall mean direction (N=10, Dec=1.1°, Inc=34.1°, k=531 and α95=2.1°) is characterized by small angular dispersion and inclination close to dipolar value for the locality. Anisotropy of magnetic susceptibility lineation match the geologically inferred flow direction.

  1. Ground-water resources of the Holloman Air Force Base well field area, 1967, New Mexico

    USGS Publications Warehouse

    Ballance, W.C.; Mattick, Robert E.

    1976-01-01

    Water consumption at Holloman Air Force Base (HAFB), N. Mex., reached an all time high in 1964 and 1965. Further increases in withdrawal without expansion of pumping facilities will hasten the chemical deterioration of the ground water pumped from the well fields. Saline water in the well-field area is present on the north and west sides of the potable-water area and in a thin shallow zone that overlies the potable-water sands in part of the potable-water area. The latter source is affecting quality of the water produced from most wells. The saturated thickness of material underlying the Boles well field ranges from about 3 ,500 feet in the western part of the field to about 1,200 feet in the eastern part of the field. In the Douglass and San Andres well fields, the saturated thickness ranges from 3,500 feet to about 300 feet. Expansion of the Boles and San Andres well fields to the east and southeast would move the center of pumping away from the highly saline water to the north and west. This would eliminate overpumping of the present wells that has resulted from the expanded facilities at Holloman Air Force Base. (Woodard-USGS)

  2. Genetic variation in Bactericera cockerelli (Hemiptera: Triozidae) from Mexico.

    PubMed

    Lopez, Beatriz; Favela, Susana; Ponce, Gustavo; Foroughbakhch, Rahim; Flores, Adriana E

    2013-04-01

    Bactericera cockerelli (Sulc) is a significant pest of several solanacious crops in Mexico and the United States since 1970. In 2001 significant outbreaks of outstanding importance were observed for the first time in areas where infestations of this insect were historically rare. Molecular studies revealed that this was because of the development of a new biotype of B. cockerelli that had become adapted to south-western United States, further demonstrating that this genetic differentiation was reflected in the survival, development cycle, fertility, and growth rate of both the native biotype as well as the one recently reported. To determine genetic variation in populations of B. cockerelli from Mexico, inter simple sequence repeat were used. Results showed that populations of B. cockerelli from central and northeastern Mexico (Guanajuato, Morelos, Estado de Mexico, and Nuevo Leon states) are genetically similar, meanwhile B. cockerelli from northwest, southwest, and southeast of the country (Sinaloa, Michoacan, and Oaxaca states) are genetically distinct from each other and from the rest of the populations included in the study.

  3. Fluid circulation and reservoir conditions of the Los Humeros Geothermal Field (LHGF), Mexico, as revealed by a noble gas survey

    NASA Astrophysics Data System (ADS)

    Pinti, Daniele L.; Castro, M. Clara; Lopez-Hernandez, Aida; Han, Guolei; Shouakar-Stash, Orfan; Hall, Chris M.; Ramírez-Montes, Miguel

    2017-03-01

    Los Humeros Geothermal Field (LHGF) is one of four geothermal fields currently operating in Mexico, in exploitation since 1990. Located in a caldera complex filled with very low-permeability rhyolitic ignimbrites that are the reservoir cap-rock, recharge of the geothermal field is both limited and localized. Because of this, planning of any future geothermal exploitation must be based on a clear understanding of the fluid circulation. To this end, a first noble gas survey was carried out in which twenty-two production wells were sampled for He, Ne, Ar, Kr, and Xe isotope analysis. Air-corrected 3He/4He ratios (Rc) measured in the fluid, normalized to the helium atmospheric ratio (Ra; 1.384 × 10- 6), are consistently high across the field, with an average value of 7.03 ± 0.40 Ra. This value is close to that of the sub-continental upper mantle, indicating that LHGF mines heat from an active magmatic system. Freshwater recharge does not significantly affect He isotopic ratios, contributing 1-10% of the total fluid amount. The presence of radiogenic 40Ar* in the fluid suggests a fossil fluid component that might have circulated within the metacarbonate basement with radiogenic argon produced from detrital dispersed illite. Solubility-driven elemental fractionation of Ne/Ar, Kr/Ar, and Xe/Ar confirm extreme boiling in the reservoir. However, a combined analysis of these ratios with 40Ar/36Ar reveals mixing with an air component, possibly introduced by re-injected geothermal fluids.

  4. Map showing geology, oil and gas fields, and geologic provinces of the Gulf of Mexico region

    USGS Publications Warehouse

    French, Christopher D.; Schenk, Christopher J.

    2006-01-01

    This map was created as part of a worldwide series of geologic maps for the U.S. Geological Survey's World Energy Project. These products are available on CD-ROM and the Internet. The goal of the project is to assess the undiscovered, technically recoverable oil and gas resources of the world. Two previously published digital geologic data sets (U.S. and Caribbean) were clipped to the map extent, while the dataset for Mexico was digitized for this project. Original attributes for all data layers were maintained, and in some cases, graphically merged with common symbology for presentation purposes. The world has been divided into geologic provinces that are used for allocation and prioritization of oil and gas assessments. For the World Energy Project, a subset of those provinces is shown on this map. Each province has a set of geologic characteristics that distinguish it from surrounding provinces. These characteristics may include dominant lithologies, the age of the strata, and/or structural type. The World Geographic Coordinate System of 1984 is used for data storage, and the data are presented in a Lambert Conformal Conic Projection on the OFR 97-470-L map product. Other details about the map compilation and data sources are provided in metadata documents in the data section on this CD-ROM. Several software packages were used to create this map including: Environmental Systems Research Institute, Inc. (ESRI) ArcGIS 8.3, ArcInfo software, Adobe Photoshop CS, Illustrator CS, and Acrobat 6.0.

  5. A field study of reproductive performance and productivity of Pelibuey ewes in Southeastern Mexico.

    PubMed

    Magaña-Monforte, Juan Gabriel; Huchin-Cab, Miguel; Ake-López, Ricardo Jesus; Segura-Correa, Jose Candelario

    2013-11-01

    The objective was to evaluate the reproductive performance and productivity of Pelibuey ewes in two flocks in Southeastern Mexico. Animals grazed on irrigated star grass (Cynodon plectostachyus). In flock 1, lambs grazed with their mothers from 7 to 70 days of age (weaning age), whereas in flock 2, they were confined and offered chopped grass, a commercial concentrated and managed under restricted suckling until weaning at 60 days of age.. The statistical model included the fixed effects of flock, year and season of lambing, parity number, litter size at weaning, first order interactions and the random effects of ewe and the error term. The means ± SD for age at first lambing, prolificacy, lambing interval (LI), weaning weight, and productivity were 477 ± 85.5 days, 1.41 ± 0.51 lambs, 255.9 ± 51.8 days, 16.5 ± 4 kg, and 18.1 ± 4.42 kg of lamb weaned, respectively. Repeatability estimates for the latter four traits were 0.09, 0.07, 0.11, and 0.13, respectively. All main effects in the models were significant (P < 0.001), except for year on LI. Prolificacy and productivity increased with parity number. The shortest LI was in the rainy season. Ewes with two or three lambs produced 8 and 14 kg of lamb more at weaning than single lamb ewes. In conclusion, reproductive performance and productivity could be improved, and the low repeatability estimates suggest that management should be used in a short term rather than genetic approaches.

  6. Evolution of long-term land subsidence near Mexico City: Review, field investigations, and predictive simulations

    NASA Astrophysics Data System (ADS)

    Ortiz-Zamora, Dalia; Ortega-Guerrero, Adrian

    2010-01-01

    Aquitard consolidation in the Chalco Plain is the most recent of a series of major land subsidence problems near Mexico City caused by leaky-aquifer pumping and involving a complex distribution of basalt flows within a lacustrine sequence. This study first conducted a ground magnetic survey combined with lithologic logs to map the extension of basalts. Then it assessed the evolution of ground surface elevations and updated hydraulic heads in the aquifer and aquitard in order to verify the accuracy of previous simulations and develop new predictions on land subsidence employing a one-dimensional, nonlinear, groundwater flow-consolidation model. Results show the presence of shallow basalts that extend from Sierra Santa Catarina into the Chalco Plain, causing a differential consolidation that controls both the distribution of large-scale fractures in the aquitard and the shape of a new lake. Cumulative land subsidence in the center of the Chalco Plain reached 13 m in 2006, thus closely matching previous numerical estimations. Since 1985, the ground surface decline has continued at a rate of ˜0.40 m/yr, while the potentiometric surface decline in the aquifer proceeds at an average rate of ˜1.5 m/yr, indicating that the flow system has not yet reached steady-state conditions. Numerical predictions show that under current pumping rates, where the aquitard is 300 m, total land subsidence will reach ˜19 m by the year 2020; while where the aquitard is 140 m thick, total land subsidence will reach ˜12 m, and increase the risk of flooding and aquitard fracturing for nearby urban centers.

  7. Perspectives on Safety and Health among Migrant and Seasonal Farmworkers in the United States and Mexico: A Qualitative Field Study

    ERIC Educational Resources Information Center

    Stallones, Lorann; Acosta, Martha S. Vela; Sample, Pat; Bigelow, Philip; Rosales, Monica

    2009-01-01

    Context: A large number of hired farmworkers in the United States come from Mexico. Understanding safety and health concerns among the workers is essential to improving prevention programs. Purpose: The purpose of this pilot study was to obtain detailed information about safety and health concerns of hired farmworkers in Colorado and in Mexico.…

  8. New Mexico Forest Inventory and Analysis: American Recovery and Reinvestment Act Project, Field Report: 2010-2012

    Treesearch

    Mary Stuever; John Capuano

    2014-01-01

    For a 3-year period, from 2010-2012, the New Mexico Forestry Division utilized contractors to collect Forest Inventory and Analysis (FIA) data in New Mexico. Funded through the American Recovery and Reinvestment Act, the State partnered with the Interior West FIA Program. Together, both agencies collected data on approximately 6,450 plots. This effort represents the...

  9. Perspectives on Safety and Health among Migrant and Seasonal Farmworkers in the United States and Mexico: A Qualitative Field Study

    ERIC Educational Resources Information Center

    Stallones, Lorann; Acosta, Martha S. Vela; Sample, Pat; Bigelow, Philip; Rosales, Monica

    2009-01-01

    Context: A large number of hired farmworkers in the United States come from Mexico. Understanding safety and health concerns among the workers is essential to improving prevention programs. Purpose: The purpose of this pilot study was to obtain detailed information about safety and health concerns of hired farmworkers in Colorado and in Mexico.…

  10. Evolution of a magmatic system during continental extension: The Mount Taylor volcanic field, New Mexico

    SciTech Connect

    Perry, F.V. ); Baldridge, W.S. ); DePaolo, D.J. Lawrence Berkeley Lab., Berkeley, CA ); Shafiqullah, M. )

    1990-11-10

    In this paper the authors present geologic mapping, K-Ar chronology, major and trace element data, mineral chemistry, and Nd, Sr, and O isotopic data for volcanic rocks of the Mount Taylor volcanic field (MTVF). The MTVF lies on the tectonic boundary between the Basin and Range province and the southeastern Colorado Plateau and is dominated by Mount Taylor, a composite volcano active from {approx}3 to 1.5 m.y. ago. Growth of the volcano began with eruption of rhyolite, followed by quartz latite and finally latite. Basalts erupted throughout the lifetime of the volcano. Rare mixing of evolved hy-hawaiite and rhyolite produced a few intermediate magmas, primarily in the early history of the field. Mixing may have occurred when rhyolite magmas in the lower crust ascended to upper crustal levels and were injected into the bases of mafic magma chambers. Small amounts of crustal assimilation accompanied fractional crystallization and affected all the evolved MTVF rocks. Assimilation/fractional crystallization occurred primarily in the lower crust as hy-hawaiite differentiated to mugearite or latite. Early in the history of the field, evolved lower crustal magmas ascended into the upper crust, where density filtering and a reduced tensional stress field inhibited further ascent until magmas evolved to rhyolite or quartz latite. Later in the history of the field, latite magmas ascended directly from the lower crust and erupted without further significant differentiation because of increased crustal extension.

  11. Salt Mechanics Primer for Near-Salt and Sub-Salt Deepwater Gulf of Mexico Field Developments

    SciTech Connect

    FOSSUM, ARLO F.; FREDRICH, JOANNE T.

    2002-07-01

    The Gulf of Mexico (GoM) is the most active deepwater region in the world and provides some of the greatest challenges in scope and opportunity for the oil and gas industry. The complex geologic settings and significant water and reservoir depths necessitate high development costs, in addition to requiring innovating technology. The investment costs are substantial: because of the extreme water depths (up to 8000 feet) and considerable reservoir depths (to 30,000 feet below mudline), the cost of drilling a single well can be upwards of 50 to 100 million dollars. Central, therefore, to successful economic exploitation are developments with a minimum number of wells combined with a well service lifetime of twenty to thirty years. Many of the wells that are planned for the most significant developments will penetrate thick salt formations, and the combined drilling costs for these fields are estimated in the tens of billions of dollars. In May 2001, Sandia National Laboratories initiated a Joint Industry Project focused on the identification, quantification, and mitigation of potential well integrity issues associated with sub-salt and near-salt deepwater GoM reservoirs. The project is jointly funded by the DOE (Natural Gas and Oil Technology Partnership) and nine oil companies (BHP Billiton Petroleum, BP, ChevronTexaco, Conoco, ExxonMobil, Halliburton, Kerr-McGee, Phillips Petroleum, and Shell). This report provides an assessment of the state of the art of salt mechanics, and identifies potential well integrity issues relevant to deepwater GoM field developments. Salt deformation is discussed and a deformation mechanism map is provided for salt. A bounding steady-state strain rate contour map is constructed for deepwater GoM field developments, and the critical issue of constraint in the subsurface, and resultant necessity for numerical analyses is discussed.

  12. Morphological Study of Jaraguay and San Borja Volcanic Fields, Baja California, Mexico.

    NASA Astrophysics Data System (ADS)

    Negrete-Aranda, R.; Canon-Tapia, E.

    2005-12-01

    Volcanism younger than 12.5 Ma has occurred mainly as monogenetic volcanic fields along the Baja California Peninsula, but until now very little attention has been given to the morphological description of this type of volcanism. In this study we present the preliminary results of the first stage of elaboration of a Geographical Information System (GIS) of the northernmost volcanic fields of the Peninsula; Jaraguay and San Borja, which are among the less studied fields in the region. The present status of the GIS includes the main morphological characteristics and localization of over 350 eruptive centers identified in both volcanic fields. Our data show that over 90% of the eruptive centers are cinder cones, whereas the rest of volcanic structures include some stratovolcanos, shield volcanoes and calderas. Detailed analysis of digital elevation models and 14 m resolution Landsat TM images show a remarkable diversity of the size of reported eruptive centers: the average height lies around 720 m with peaks that reaches 1,412 m asl. Preliminary graphic analyses show local concentrations of the biggest volcanic structures in some areas in both fields. This spatial distribution is more evident at the San Borja volcanic field where the biggest volcanic centers are systematically located in its south and north-western boundaries. A similar concentration of bigger volcanic structures is found at the western edge of Jaraguay volcanic field where cinder cones are largely confined to its eastern most edge. The observed morphological changes of volcanic structures occur in both cases within a distance of less than 100 km. We interpret such variations as the result of heterogeneities of the low velocity zone below this particular area of the Baja California Peninsula, although the final evaluation of the distribution of the regional stress field and its relationship with the actual spatial distribution of eruptive centers must wait until more information becomes available. In

  13. Anthropogenic effects on soil quality in ancient terraced agricultural fields of Chihuahua, Mexico

    USDA-ARS?s Scientific Manuscript database

    Agricultural soil quality was investigated in ancient field systems near Casas Grandes (also known as Paquimé), one of the largest and most complex prehistoric settlements in the North American Southwest. This research was completed as part of an interdisciplinary study of the anthropogenic ecology...

  14. Financial administration of work for nonfederal sponsors, DOE Field Office (AL), Albuquerque, New Mexico

    SciTech Connect

    Not Available

    1991-09-30

    The Department of Energy (DOE) Field Office, Albuquerque (AL) is responsible for managing and controlling nonfederally sponsored work done by Los Alamos National Laboratory (LANL). The audit objective was to determine whether the funding of, and accounting for, work done under a 1984 funds-in agreement and work for others in Fiscal Year (FY) 1989 complied with laws, regulations, and policies.

  15. Pre- and post-exploitation variations in hydrothermal activity in Los Humeros geothermal field, Mexico

    NASA Astrophysics Data System (ADS)

    Prol-Ledesma, R. M.

    1998-08-01

    Los Humeros geothermal field is a remarkable example of the lack of water-rock equilibrium. Significant variations of hydrothermal activity have occurred before and after exploitation started. Presently, discharged water is not in equilibrium with the alteration suite observed in the reservoir rocks. Hydrothermal minerals identified in core and cuttings define the occurrence of several stages of hydrothermal activity. Cooling at depth is inferred from fluid inclusion and alteration mineralogy data from the wells located nearby Los Humeros fault. Most wells produce a two-phase fluid with excess enthalpy, this accounts for the high CO 2 content observed in the discharged fluid. Sulfur and carbon isotopic data indicate that volatile species in the geothermal fluid have magmatic as well as sedimentary components, while strontium isotopic composition shows that calcium is provided by the andesitic rocks that form the reservoir. As exploitation of the field started, concentration of HCl increased in the discharged fluids. This shows that recharge of the reservoir is not enough to balance the output for production, and drying out of the field may be taking place at depth. The lack of chemical equilibrium and the presence of gases of magmatic origin suggest that Los Humeros is a relatively young geothermal field related to a recent magmatic intrusion.

  16. An Early Researcher in the Field of Education: Bernardino de Sahagun in Sixteenth-Century Mexico

    ERIC Educational Resources Information Center

    Spieker, Susanne

    2008-01-01

    Bernardino de Sahagun (1499/1500-1590), a Franciscan missionary in the colony of New Spain, can be seen as an early researcher in the field of education. Through his ethnographic work "General History of the Things of New Spain" he has been most influential in the historiography of Meso-American pre-Hispanic cultures. This paper focuses…

  17. Lahars simulation and field calibration in Popocatépetl Volcano (Mexico)

    NASA Astrophysics Data System (ADS)

    Haddad, B.; Zamorano, J. J.; Pastor, M.; Andrés, N.; Tanarro, L. M.; Palacios, D.

    2012-04-01

    The term "lahar" refers to the process generated in volcanoes by high sediment concentration flows that range from hyperconcentrated to Debris flows. This complex dynamic system represents a threat to people living near volcanoes. In order to delimitate hazardous area, mathematical models should be applied and tested. These models depend strongly on data collected in the field and, an additionally, good DEM is required to produce satisfactory results. Recent Popocatépetl lahars are well documented and as a result, they can be used to assess the accuracy of numerical models. In this work, SPH (Smoothed Particle Hydrodynamics) depth integrated model created by Pastor in 2005 is applied to reproduce Popocatépetl lahars. The mathematical model is derived from the velocity-pressure version of the Biot-Zienkiewicz model and the assumed rheology corresponds to the Bingham model. On the other hand, a systematic collection of field data it's carried out by GFAM group in Popocatépetl volcano and it's included updating channel topography; as well as the factors: i) run out area boundary; ii) estimation of the velocity of the flow and iii) depth distribution of lahar's deposit. All this field data it's used for back analyses and calibration of the rheological parameters. Besides the calibration of rheological parameters, it is also investigated the effect of the topographic mesh resolution. Moreover, flow depth obtained by SPH model is systematically compared with field evidences along the lahar's path. Research funded by CGL2009-7343 project, Government of Spain.

  18. Summary of recent progress in understanding the Cerro Prieto Geothermal Field, Baja, California, Mexico

    SciTech Connect

    Lippmann, M.J.; Witherspoon, P.A.

    1980-07-01

    Geological and geophysical studies indicate that the Cerro Prieto reservoir is quite heterogeneous due to complex lithofacies fault structures, and hydrothermal alteration. Geochemical investigations have provided clues on the origin of the geothermal fluids, their recharge paths and on the reservoir processes accompanying the exploitation of the field. Well tests have yielded information on the permeability of the reservoir. (MHR)

  19. Space treatments of insecticide for control of dengue virus vector Aedes aegypti in southern Mexico. I. Baseline penetration trials in open field and houses.

    PubMed

    Arrendondo-Jimenez, Juan I; Rivero, Norma E

    2006-06-01

    We studied the efficacy of space ultra-low volume treatments of 3 insecticides for the control of the dengue virus vector Aedes aegypti in southern Mexico. Insecticides tested were permethrin (Aqua-Reslin Super), d-phenothrin (Anvil), and cyfluthrin (Solfac), applied at rates of 10.87, 7.68, and 2 g/ha, respectively, by using London Fog, HP910-PHXL, or Micro-Gen pumps mounted on vehicles. Studies included 1) open field penetration tests and 2) house penetration tests. Open field tests indicated that Anvil and Solfac were more effective than Aqua-Reslin Super. In house tests, Anvil yielded the highest mosquito mortalities (>/=88%) of the three insecticides in the front porch, living room, bedroom, and backyard. Therefore, Anvil proved to be better than other insecticides evaluated to control Ae. aegypti in Chiapas, Mexico.

  20. Characterization and prediction of spatial variability of unsaturated hydraulic properties in a field soil: Las Cruces, New Mexico

    SciTech Connect

    Yeh, T.C.J.; Greenholtz, D.E.; Nash, M.S.; Wierenga, P.J.

    1991-12-31

    A 91-m transect was set up in an irrigated field near Las Cruces, New Mexico to investigate the spatial variability of unsaturated soil properties. A total of 455 sampling points were monitored along a grid consisting of 91 stations placed 1 m apart by 5 depths per station. Post-irrigation soil water tension and water content measurements were recorded over 45 days at 11 time periods. The instantaneous profile was used to estimate the unsaturated hydraulic conductivity at the 455 sampling points. Fifty soil samples were also taken for analyzing sand, silt, and clay content distributions. The spatial and temporal variability of soil water tension and water content were investigated along with the spatial variability of parameters of an unsaturated hydraulic conductivity model. Results of the analysis show that spatial variation in soil water tension and water content is consistent with the soil texture spatial variability. In addition, the spatial distribution of the estimated parameter value of unsaturated hydraulic conductivity reflects the soil texture distribution. Using the statistics of the estimated hydraulic parameter values, a stochastic soil water tension model was employed to reproduce the variability of observed soil water tension. Although many assumptions were made, the results of the simulation appear promising.

  1. Characterization and prediction of spatial variability of unsaturated hydraulic properties in a field soil: Las Cruces, New Mexico

    SciTech Connect

    Yeh, T.C.J.; Greenholtz, D.E. . Dept. of Hydrology and Water Resources); Nash, M.S. . Dept. of Crop and Soil Sciences); Wierenga, P.J. . Dept. of Soil and Water Science)

    1991-01-01

    A 91-m transect was set up in an irrigated field near Las Cruces, New Mexico to investigate the spatial variability of unsaturated soil properties. A total of 455 sampling points were monitored along a grid consisting of 91 stations placed 1 m apart by 5 depths per station. Post-irrigation soil water tension and water content measurements were recorded over 45 days at 11 time periods. The instantaneous profile was used to estimate the unsaturated hydraulic conductivity at the 455 sampling points. Fifty soil samples were also taken for analyzing sand, silt, and clay content distributions. The spatial and temporal variability of soil water tension and water content were investigated along with the spatial variability of parameters of an unsaturated hydraulic conductivity model. Results of the analysis show that spatial variation in soil water tension and water content is consistent with the soil texture spatial variability. In addition, the spatial distribution of the estimated parameter value of unsaturated hydraulic conductivity reflects the soil texture distribution. Using the statistics of the estimated hydraulic parameter values, a stochastic soil water tension model was employed to reproduce the variability of observed soil water tension. Although many assumptions were made, the results of the simulation appear promising.

  2. Heavy-Duty Vehicle Emissions in the Mexico City Metropolitan Area during the MCMA-2003 Field Measurement Campaign

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Dunlea, E. J.; Marr, L.; Slott, R. S.; Molina, L. T.; Molina, M. J.; Herndon, S. C.; Jayne, J. T.; Shorter, J. H.; Worsnop, D.; Zahniser, M.; Onasch, T.; Kolb, C. E.; Rogers, T.; Knighton, B.

    2004-12-01

    On-road vehicle emissions were measured in the Mexico City Metropolitan Area (MCMA) as part of an intensive, five-week, field campaign held in the spring of 2003 (April 1 - May 5). Vehicle emissions measurements were made during vehicle chase experiments using the Aerodyne Mobile Laboratory. The mobile lab was equipped with a large suite of state-of-the-art analytical instruments for measuring both gas and particle phase chemical components from vehicle emissions in real time. The experiment represents a real-world sample of more than 200 in-use vehicles. The results presented here focus on heavy-duty gasoline (HDGT) and heavy-duty diesel trucks (HDDT), although measurements included pick up trucks, colectivos (microbuses), and private automobiles as well. The use of covariance and fitting methods for individual species vs. CO2 allows the estimation of individual emission ratios in a real time plume-based analysis. The variability of emission ratios within a vehicle class and during different driving modes (acceleration, idling, etc.) are explored. Results are reported as molar emission ratios of emission gases with carbon dioxide. These and other vehicle-related emissions measured during the campaign will be presented and discussed. These types of studies are important for the development of emission inventories and their use in air quality modeling studies in urban areas.

  3. On-Road Measurement of Vehichle VOC Emission Measurements During the 2003 Mexico City Metropolitan Area Field Campaign

    NASA Astrophysics Data System (ADS)

    Knighton, W. B.; Rogers, T.; Grimsrud, E.; Herndon, S.; Allwine, E.; Lamb, B.; Velasco, E.; Westberg, H.

    2004-12-01

    In the spring of 2003 (April 1-May 5), a multinational team of experts conducted an intensive, five-week field campaign in the Mexico City Metropolitan Area (MCMA). The overall goal of this effort was to contribute to the understanding of the air quality problem in megacities. As part of the campaign the Aerodyne Mobile Laboratory was equipped with state-of-the-art analytical instruments and deployed for measuring a variety of vehicle emissions in real time including CO2, NO2, NH3, HCHO, VOC's and volatile (at 600 °C) aerosol. The on-road measurement of vehicle VOC emissions were performed using a commercial version of the IONICON PTR-MS modified to operate onboard the mobile lab platform. A summary of the PTR-MS results from these and supporting laboratory experiments will be presented and discussed. In particular, selected chase events will be presented to illustrate the utility of the PTR-MS technique for characterizing vehicle VOC emission profiles in real time. VOC emission profiles for different vehicle engine types which include gasoline, diesel and compressed natural gas will be discussed and compared to the measurements from other high time response instruments deployed on the Aerodyne mobile van.

  4. Field evaluation of Mesocyclops longisetus (Copepoda: Cyclopoidea) for the control of larval Aedes aegypti (Diptera Culicidae) in northeastern Mexico.

    PubMed

    Gorrochotegui-Escalante, N; Fernandez-Salas, I; Gomez-Dantes, H

    1998-09-01

    Field trials of the predacious copepod Mesocyclops longisetus Thiubaud were conducted in northeastern Mexico to determine the effectiveness of this species to control larval Aedes aegypti (L.) populations and to survive and reproduce in nature. Groups of 200, 50, and 50 ovigerous M. longisetus females were inoculated into 200-liter metal drums, discarded tires, and cemetery flower vases, respectively, which are 3 of the more important Aedes breeding sites in this area. Larvae were sampled at 15-d intervals, and total surviving cyclops were collected at the end of the study, 120 d later. Community participation was solicited through a simple training program on copepod rescue before drum cleaning and facilitated by the addition of a drum marker to remind residents of copepod presence. Results showed good cooperation and after 4 mo all peridomestic drums, still supported variable numbers of cyclopoids. Average of larvae reduction was 37.5% for drums, 67.5% for flower vases, and 40.9% for tires. This study shows difficulties of using cyclopoids for tires and vases in areas where prolonged dry seasons desiccated these habitats and reduced copepod survival.

  5. Synthetic peptide vaccine against Taenia solium pig cysticercosis: successful vaccination in a controlled field trial in rural Mexico.

    PubMed

    Huerta, M; de Aluja, A S; Fragoso, G; Toledo, A; Villalobos, N; Hernández, M; Gevorkian, G; Acero, G; Díaz, A; Alvarez, I; Avila, R; Beltrán, C; Garcia, G; Martinez, J J; Larralde, C; Sciutto, E

    2001-10-12

    Taenia solium cysticercosis seriously affects human health when localised in the central nervous system (CNS) and causes great economic loss in pig husbandry in rural areas of endemic countries. Increasing the resistance to the parasite in the obligatory host pig may help in curbing transmission. Three synthetic peptides based on protein sequences of the murine parasite Taenia crassiceps, which had previously been shown to induce protection in mice against homologous challenge, were tested as a vaccine against T. solium cysticercosis in pigs. Vaccinated and unvaccinated piglets (240 in all) were distributed in pairs among the peasants' households of two rural villages in Mexico in which 14% of the native pigs were cysticercotic. Ten to twelve months later, the effect of vaccination was evaluated at necropsy. Vaccination decreased the total number of T. solium cysticerci (98.7%) and reduced the prevalence (52.6%). The natural challenge conditions used in this field trial strengthen the likelihood of successful transmission control to both pig and human through a large-scale pig vaccination program. We believe this is a major contribution in anticysticercosis vaccine development as these rather simple yet protective peptides are potentially more cost-effective to produce and less variable in results than antigens that are more complex.

  6. Paleosecular variation and time-averaged field recorded in late Pliocene-Holocene lava flows from Mexico

    NASA Astrophysics Data System (ADS)

    Mejia, V.; BöHnel, H.; Opdyke, N. D.; Ortega-Rivera, M. A.; Lee, J. K. W.; Aranda-Gomez, J. J.

    2005-07-01

    This paper presents results from 13 paleomagnetic sites from an area west of Mexico City and 7 sites from an area of dispersed monogenetic volcanism in the state of San Luis Potosi, accompanied by seven 40Ar/39Ar radiometric dates. An analysis of secular variation and time-averaged paleomagnetic field in the Trans-Mexican Volcanic Belt (TMVB), using compiled data both newly obtained and from the literature, is presented. Interpretation can best be constrained after excluding from the data set sites that appear to be tectonically affected. The selected data include 187 sites of late Pliocene-Holocene age. The mean direction among these sites is Dec = 358.8°, Inc = 31.6°, α95 = 2.0°, k = 29. This direction does not overlap the expected geocentric axial dipole (GAD) but is consistent with a GAD plus a 5% quadrupole. The virtual geomagnetic pole scatter of this group of sites (12.7°, with lower and upper 95% confidence limits of 11.9° and 14.1°) is consistent with the value expected from Model G (13.6°).

  7. Archeological Investigations in Cochiti Reservoir, New Mexico. Volume 3. 1976-1977 Field Seasons.

    DTIC Science & Technology

    1979-01-01

    animals (woodrat, gopher , land- snail and mouse) may have been intrusive. The types of Direct evidence of food resources procured and con- individuals... Pocket Gopher ) represented one adult. There was one Eight lithics were recovered from the surface of LA unidentified fragment. One bone from a rabbit...Investigator; John B. Broster, who served as Project Director and Field Supervisor during The wearisome job of typing (and retyping) the mul- the first

  8. Stratigraphic relations and lithologic variations in the Jemez Volcanic Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Gardner, Jamie N.; Goff, Fraser; Garcia, Sammy; Hagan, Roland C.

    1986-02-01

    Over 100 radiometric dates and recent detailed geologic mapping allow some refinements of the stratigraphic relations of major units and generalization of temporal lithologic variations in the Jemez volcanic field. Volcanism had begun in the area by about 16.5 Ma with episodic eruptions of alkaline basalts. By 13 Ma, alkaline volcanism had been replaced with eruptions of more voluminous olivine tholeiite. High-silica rhyolite, derived from melts of lower crust, also was erupting by about 13 Ma. Basalt and high-silica rhyolite continued to be erupted until about 7 and 6 Ma, respectively, but effusions of dominantly andesitic differentiates of basalt that began as early as about 12 Ma volumetrically overshadowed all other eruptive products between 10 and 7 Ma. From 7 to 3 Ma the dominant erupted lithology was dacite, which appears to have been generated by mixing of magmas whose compositions are approximated by earlier andesites and high-silica rhyolites. Less than 4-3 Ma volcanism was dominated by eruption of rhyolitic tuffs. Field relations, geochemistry, and dates specifically indicate the following with regards to stratigraphie relations: (1) distinctions among basalt of Chamisa Mesa, Paliza Canyon Formation basalts, and Lobato Basalt for other than geographic reasons are artificial; basaltic volcanism was continuous in volcanic field from >13 to 7 Ma, (2) Canovas Canyon and Bearhead rhyolites form a continuum of high-silica rhyolite volcanism from >13 to 6 Ma, (3) hypabyssal and volcanic rocks of the Cochiti mining district probably represent the exhumed interior of a Keres Group volcano(s), (4) temporal overlaps exist among the major stratigraphie groups which may imply some genetic relations, and (5) the Tewa Group formation Cerro Rubio Quartz Latite may more appropriately be considered part of the Tschicoma Formation of the Polvadera Group. Preliminary analysis of hydrothermal alteration in the context of the volcanic stratigraphy suggests at least three

  9. Final Environmental Assessment for the Boles Wells Field Perimeter Security Improvement Project Otero County, New Mexico

    DTIC Science & Technology

    2005-10-03

    findings of the Final Environmental Assessment of the Boles Wells Field Security Improvement Project, dated 3 Oct 05, no significant impact on human health ...Other resource impacts identified in the EA were considered to determine the potential for high and adverse health and environmental impacts to human ...as necessary, to protect human health and the environment. - Noted. To be accomplished asnecesary. Final Environmental Assessment - Boles Wells

  10. Initial Measurements of Petrophysical Properties on Rocks from the Los Azufres, Mexico, Geothermal Field

    SciTech Connect

    Contreras, E.; Iglesias, E.; Razo, E.

    1986-01-21

    Petrophysical properties of geothermal reservoir rocks are valuable information for many activities, including reservoir characterization, modeling, field test analysis and planning of exploitation techniques. Petrophysical data of rocks from geothermal reservoirs located in volcanic areas is in general very scarce. In particular, no petrophysical data of rocks from the Los Azufres geothermal field area has ever been published. This work presents the results of initial petrophysical studies on outcrop rocks and drill core samples from the Los Azufres geothermal field. These studies are the first part of an ongoing experimental program intended to establish a data-base about physical properties of the Los Azufres rocks, in support of the many reservoir engineering activities which require of such information. The experimental work carried out consisted of laboratory measurements of density, porosity, permeability, compressibility, thermal conductivity, thermal expansion, electrical resistivity and sonic wave velocities. Some of the experiments were aimed at investigation of the effects of temperature, pressure, saturation and other parameters on the physical properties of rocks.

  11. Microanalysis of the aerosol collected over south-central New Mexico during the alive field experiment, May-December 1989

    NASA Astrophysics Data System (ADS)

    Sheridan, Patrick J.; Schnell, Russel C.; Kahl, Jonathan D.; Boatman, Joe F.; Garvey, Dennis M.

    Thirty-eight size-segregated aerosol samples were collected in the lower troposphere over the high desert of south-central New Mexico, using cascade impactors mounted onboard two research aircraft. Four of these samples were collected in early May, sixteen in mid-July, and the remaining ones in December 1989, during three segments of the ALIVE field initiative. Analytical electron microscope analyses of aerosol deposits and individual particles from these samples were performed to physically and chemically characterize the major particulate species present in the aerosol. Air-mass trajectories arriving at the sampling area in the May program were quite different from those calculated for the July period. In general, the May trajectories showed strong westerly winds, while the July winds were weaker and southerly, consistently passing over or very near the border cities of El Paso, Texas, and Ciudad Juarez, Mexico. Aerosol samples collected during the May period were predominantly fine (0.1-0.5 μm dia.), liquid H 2SO 4 droplets. Samples from the July experiment were comprised mostly of fine, solid (NH 4) 2SO 4 or mostly neutralized sulfate particles. In both sampling periods, numerous other particle classes were observed, including many types with probable terrestrial or anthropogenic sources. The numbers of these particles, however, were small when compared with the sulfates. Composite particle types, including sulfate/crustal and sulfate/carbonaceous, were also found to be present. The major differences in aerosol composition between the May and July samples (i.e. the extensive neutralization of sulfates in the July samples) can be explained by considering the different aerosol transport pathways and the proximity of the July aerosol to the El Paso/Juarez urban plume. Winds during the December experiment were quite variable, and may have contributed to the widely varying aerosol compositions observed in these samples. When the aircraft sampled the El Paso

  12. Paleomagnetism and Tectonic Interpretations of the Taos Plateau Volcanic Field, Rio Grande Rift, New Mexico

    NASA Technical Reports Server (NTRS)

    Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

    1993-01-01

    The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to the late stage extensional environment of the Rio Grande rift was investigated using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chiron. Alternating field demagnetization, aided by principal component analysis, yields 55 sites with stable directions representing both normal and reversed polarities, and five sites indicating transitional fields. Mean direction of the normal and inverted reversed sites is I=49.3 deg. and D=356.7 deg. (alpha(sub 95)=3.6 deg). Angular dispersion of the virtual geomagnetic poles is 16.3 deg, which is consistent with paleosecular variation model G, fit to data from the past 5 m.y. Comparison with the expected direction indicates no azimuthal rotation of the Taos Plateau volcanic field; inclination flattening for the southern part of the plateau is 8.3 deg +/- 5.3 deg. Previous paleomagnelic data indicate 10 deg- 15 deg counterclockwise rotation of die Espanola block to the south over the past 5 m.y. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern

  13. Paleomagnetism and Tectonic Interpretations of the Taos Plateau Volcanic Field, Rio Grande Rift, New Mexico

    NASA Technical Reports Server (NTRS)

    Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

    1993-01-01

    The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to the late stage extensional environment of the Rio Grande rift was investigated using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chiron. Alternating field demagnetization, aided by principal component analysis, yields 55 sites with stable directions representing both normal and reversed polarities, and five sites indicating transitional fields. Mean direction of the normal and inverted reversed sites is I=49.3 deg. and D=356.7 deg. (alpha(sub 95)=3.6 deg). Angular dispersion of the virtual geomagnetic poles is 16.3 deg, which is consistent with paleosecular variation model G, fit to data from the past 5 m.y. Comparison with the expected direction indicates no azimuthal rotation of the Taos Plateau volcanic field; inclination flattening for the southern part of the plateau is 8.3 deg +/- 5.3 deg. Previous paleomagnelic data indicate 10 deg- 15 deg counterclockwise rotation of die Espanola block to the south over the past 5 m.y. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern

  14. Field Investigations of the July 2015 Pyroclastic Density Current Deposits of Volcán de Colima, Mexico

    NASA Astrophysics Data System (ADS)

    Atlas, Z. D.; Macorps, E.; Charbonnier, S. J.; Varley, N. R.

    2016-12-01

    Small-volume pyroclastic density currents (PDCs) occur relatively frequently and pose severe threats to surrounding populations and infrastructures at active explosive volcanoes. They are characterized by short duration and complex multiphase flow dynamics due to time and space variability in their properties, which include amongst others, particle concentration, granulometry, componentry, bulk rheology and velocity. Field investigations of the deposits emplaced by small-volume concentrated PDCs aim to improve our understanding of the transport and depositional processes of these flows: time and space variations in flow dynamics within a PDC moving downslope will reflect on the distribution, grainsize and component characteristics of its deposits. Our study focuses on the recent events of July 10th and 11th, 2015 at Volcán de Colima (Mexico) where the collapse of the recent lava dome complex and a portion of the southern crater rim led to the emplacement of successive pulses of small-volume concentrated PDCs on the southern flank, along the Montegrande and San Antonio ravines. A 3-dimensional field analysis of the PDCs' deposit architecture, total grain size distribution and component properties together with a geomorphic analysis of the affected ravines provide new insights on the lateral and vertical variations of flow dynamics for some of these small-volume concentrated PDCs. Preliminary results reveal three stratigraphic units with massive block, lapilli, ash facies within the valley confined and concentrated overbank deposits with increasing content in fines with distance from the summit, suggesting an increase in fragmentation processes within the PDCs. The middle unit is characterized by a finer grainsize, a higher accidental lithic content and a lower free crystal content. Moreover, direct correlations are found between rapid changes in channel morphology and generation of overbank (unconfined) flows that escaped valley confines, which could provide the

  15. A Nimbus G pre-launch field experiment in the Gulf of Mexico, October 1977

    NASA Technical Reports Server (NTRS)

    Vanderpiepen, H.

    1977-01-01

    A large scale field experiment, which was arranged in support of the Nimbus G - Coastal Zone Color Scanner (CZCS) project was studied. The experiment was to provide three air and two shipborne platforms simultaneously to members of the Nimbus G Experiment Team (NET) and to other scientists in order to collect data from common test sites. Besides establishing fundamental relations between the light in the sea and the biochemical properties of water, the data will be used mainly for the development of algorithms during the prelaunch phase of Nimbus G.

  16. Origin of rainwater acidity near the Los Azufres geothermal field, Mexico

    USGS Publications Warehouse

    Verma, M.P.; Quijano, J.L.; Johnson, Chad; Gerardo, J.Y.; Arellano, V.

    2000-01-01

    The chemical and isotopic compositions of rainwater were monitored at Los Azufres geothermal field (88 MWe) and its surroundings during May - September 1995, which is the rainy season. Samples were collected from eight sites: three within the field, three in its surroundings and two sufficiently far from the field such that they have no geothermal input. The concentrations of Cl-, SO42- and NO3- were measured in about 350 samples and found to be generally <5 ppm. Chloride concentrations remained constant with time, but sulfate and nitrate concentrations decreased, which suggests a nearby industrial source for the sulfate and nitrate. A mixing model for Cl-, SO42- and ??34S also suggests an industrial source for the rainwater sulfur. The determination of pH was found to be necessary, but is not sufficient to characterize rainwater acidity. The Gran titration method was used to determine alkalinity with respect to equivalence point of H2CO3(*). Values of alkalinity were found to range from 10-4 to 10-6 eq/L, and were negative only for some samples from Vivero and Guadalajara. Thus, SO42- and NO3- are in general not in acidic form (i.e. balanced by Na+, Ca2+, etc. rather than H+). Sulfate ??34S values were about -1.5??? in Los Azufres and its surroundings, and in Morelia, but differed from the value of -0.2??? for Guadalajara. The ??34S values for H2S from the Los Azufres geothermal wells are in the range -3.4 to 0.0???. The ??34S ranges for the natural and anthropogenic sources for environmental sulfur overlap, making it difficult to differentiate between the contribution of different sources. However, a similarity of values of ??34S at Los Azufres and Morelia (85 km distant) suggest a regional source of sulfate that is not associated with geothermal emissions from Los Azufres. (C) 2000 Published by Elsevier Science Ltd on behalf of CNR.The chemical compositions of rainwater were analyzed at Los Azufres geothermal field in Spain from May-September 1995. The

  17. Paleomagnetism and tectonic interpretations of the Taos Plateau volcanic field, Rio Grande rift, New Mexico

    NASA Technical Reports Server (NTRS)

    Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

    1993-01-01

    The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to late stage extensional environment of the Rio Grande rift was investigate using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chron. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern corner of the counter-clockwise rotating Espanola block.

  18. Chicxulub impact: The origin of reservoir and seal facies in the southeastern Mexico oil fields

    NASA Astrophysics Data System (ADS)

    Grajales-Nishimura, José M.; Cedillo-Pardo, Esteban; Rosales-Domínguez, Carmen; Morán-Zenteno, Dante J.; Alvarez, Walter; Claeys, Philippe; Ruíz-Morales, José; García-Hernández, Jesús; Padilla-Avila, Patricia; Sánchez-Ríos, Antonieta

    2000-04-01

    Stratigraphic and mineralogic studies of Cretaceous-Tertiary (K-T) boundary sections demonstrate that the offshore oil-producing breccias and seals from oil fields in the Campeche marine platform are of K-T boundary age and that their mode of formation is probably related to the K-T impact event at Chicxulub. The oil-producing carbonate breccia and the overlying dolomitized ejecta layer (seal) found in several wells on the Campeche marine platform contain typical Chicxulub impact products, such as shocked quartz and plagioclase, and altered glass. These offshore units are correlated with thick (˜50 300 m) onshore breccia and impact ejecta layers found at the K-T boundary in the Guayal (Tabasco) and Bochil (Chiapas) sections. Regionally the characteristic sequence is composed of, from base to top, coarse-grained carbonate breccia covered by an ejecta bed and typical K-T boundary clay. The onshore and offshore breccia sequences are likely to have resulted from major slumping of the carbonate platform margin triggered by the Chicxulub impact. Successive arrival times in this area, ˜350 600 km from the crater, of seismic shaking, ballistic ejecta, and tsunami waves fit the observed stratigraphic sequence. The K-T breccia reservoir and seal ejecta layer of the Cantarell oil field, with a current daily production of 1.3 million barrels of oil, are probably the most important known oil-producing units related to an impact event.

  19. Gas chemistry and thermometry of the Cerro Prieto, Mexico, geothermal field

    USGS Publications Warehouse

    Nehring, N.L.; D'Amore, F.

    1984-01-01

    Gas compositions of Cerro Prieto wells in 1977 reflected strong boiling in the reservoir around wells M-20 and M-25. This boiling zone appeared to be collapsing in 1982 when a number of wells in this area of the field were shut-in. In 1977 and 1982, gas compositions also showed boiling zones corresponding to faults H and L postulated by Halfman et al. (1982). Four gas geothermometers were applied, based on reservoir equilibria and calculated fugacities. The Fisher - Tropsch reaction predicted high temperatures and appeared to re-equilibrate slowly, whereas the H2S reaction predicted low temperatures and appeared to re-equilibrate rapidly. Hydrogen and NH3 reactions were intermediate. Like gas compositions, the geothermometers reflected reservoir processes, such as boiling. Surface gas compositions are related to well compositions, but contain large concentrations of N2 originating from air dissolved in groundwater. The groundwater appears to originate in the east and flow over the production field before mixing with reservoir gases near the surface. ?? 1984.

  20. Paleomagnetism and tectonic interpretations of the Taos Plateau volcanic field, Rio Grande rift, New Mexico

    NASA Technical Reports Server (NTRS)

    Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

    1993-01-01

    The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to late stage extensional environment of the Rio Grande rift was investigate using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chron. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern corner of the counter-clockwise rotating Espanola block.

  1. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.; Stallard, M. L.; Nehring, N. L.; Truesdell, A. H.

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  2. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico

    USGS Publications Warehouse

    Des Marais, D.J.; Stallard, M.L.; Nehring, N.L.; Truesdell, A.H.

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330??C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher ??13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400??C) and higher (600??C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments. ?? 1988.

  3. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.; Stallard, M. L.; Nehring, N. L.; Truesdell, A. H.

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  4. Pressure Buildup Testing of Well 18 in Los Azufres Field, Mexico

    SciTech Connect

    Upton, Pedro Sanchez; Gudmundsson, Jon-Steinar

    1987-01-20

    Well 18 is a production well in the southern zone of Los Azufres geothermal field in México (see Figure 1). The well is located on the eastern flank of the drilled area, and produces a steam/water mixture from a depth of 1200-1250 m. A 19 hour pressure buildup test that was carried out in March 1986, is the subject of this paper. It is part of work reported by Sánchez-U. (1986) at the Geothermal Training Programme in Iceland. The permeability-thickness product of well 18 in Los Azufres field was determined 5.4 dm from a Horner plot. The well was found to be intersected by a fracture, as evident from the slope on a log-log plot at early time, and a skin value of -5.3. The overall pressure buildup of the well was found to be typical for double-porosity reservoir behavior, having a storativity ratio of 0.1. An outer boundary behavior was observed in the pressure buildup data. 1 tab., 6 figs., 14 refs.

  5. Increasing Interaction of Alkaline Magmas with Lower Crustal Gabbroic Cumulates over the Evolution of Mt. Taylor Volcanic Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Schmidt, M. E.; Crumpler, L. S.; Schrader, C.

    2010-12-01

    The Mount Taylor Volcanic Field at the southeastern edge of the Colorado Plateau, New Mexico erupted diverse alkaline magmas from ~3.8 to 1.5 Ma (Crumpler, 1980; Perry et al., 1990). The earliest eruptions include high silica topaz rhyolites of Grants Ridge (plagioclase, quartz, biotite) and Si-under saturated basanites and trachytes at Mt Taylor stratovolcano. Mt. Taylor was later constructed of stacks of thick, trachyandesitic to rhyolitic lava flows that were subsequently eroded into a ~4-km across amphitheatre opening toward the southeast. Early Mt. Taylor rhyolitic lavas exposed within the amphitheatre contain quartz, plagioclase, hornblende, and biotite (± sanidine) phenocrysts. Later cone-building trachydacite to trachyandesite lavas are crystal-rich with plagioclase and augite megacrysts (± hornblende, ± quartz) and record an overall trend of decreasing SiO2 with time. The last eruptions ~1.5 Ma from the stratovolcano (Perry et al. 1990) produced thick (>70 m), viscous lava flows that contain up to 50% zoned plagioclase phenocrysts. While SiO2 decreased among the silicic magmas, the degree of silica saturation increased among peripheral basaltic magmas from basanite to ne-normative hawaiite to hy-normative basalts. Evidence of increasing crustal contamination within the basalts includes zoned plagioclase megacrysts, augite and plagioclase cumulate texture xenoliths with accompanying xenocrysts. These textures within the basalts combined with abundant, complex plagioclase among the cone-building silicic magmas imply interaction and mixing with gabbroic cumulate mush in the lower crust beneath Mt. Taylor Volcano. Contemporaneous basanitic to trachytitc volcanism in the northern part of the volcanic field at Mesa Chivato (Crumpler, 1980) was more widely distributed, smaller volume, and produced mainly aphyric magmas. The lower crustal gabbroic cumulates either do not extend northward beneath Mesa Chivato, or they were not accessed by lower magma flux rate

  6. Eruptive conditions and depositional processes of Narbona Pass Maar volcano, Navajo volcanic field, Navajo Nation, New Mexico (USA)

    NASA Astrophysics Data System (ADS)

    Brand, Brittany D.; Clarke, Amanda B.; Semken, Steven

    2009-01-01

    Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution of the vent, efficiency of fragmentation, and the relative importance of magmatic and external volatiles. The basal deposits form a thick (5-20 m), massive lapilli tuff to tuff-breccia deposit. This is overlain by alternating bedded sequences of symmetrical to antidune cross-stratified tuff and lapilli tuff; and diffusely-stratified, clast-supported, reversely-graded lapilli tuffs that pinch and swell laterally. This sequence is interpreted to reflect an initial vent-clearing phase that produced concentrated pyroclastic density currents, followed by a pulsating eruption that produced multiple density currents with varying particle concentrations and flow conditions to yield the well-stratified deposits. Only minor localized soft-sediment deformation was observed, no accretionary lapilli were found, and grain accretion occurs on the lee side of dunes. This suggests that little to no liquid water existed in the density currents during deposition. Juvenile material is dominantly present as blocky fine ash and finely vesiculated fine to coarse lapilli pumice. This indicates that phreatomagmatic fragmentation was predominant, but also that the magma was volatile-rich and vesiculating at the time of eruption. This is the first study to document a significant magmatic volatile component in an NVF maar-diatreme eruption. The top of the phreatomagmatic sequence abruptly contacts the overlying minette lava flows, indicating no gradual drying-out period between the explosive and effusive phases. The lithology of the accidental clasts is consistent throughout the vertical pyroclastic

  7. The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New Mexico

    NASA Technical Reports Server (NTRS)

    Schrader, Christian M.; Crumpler, Larry S.; Schmidt, Marick E.

    2010-01-01

    The Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic

  8. Temperature field simulation with stratification model of magma chamber under Los Humeros Caldera, Puebla, Mexico

    SciTech Connect

    Verma, M.P.; Verma, S.P.; Sanvicente, H. )

    1990-01-01

    A simulation of the temperature field underlying Los Humeros caldera is obtained through numerical solution of the energy-conservation equation for a conductive heat flow process. The up-date information on geological, geochemical, geophysical and geochronological studies is used to estimate the parameters of the internal structure of the caldera. The simulation is carried out under a model of the stratification of a magma chamber. The existence of such a stratification is supported by geological and geochemical evidence. The boundary conditions, the equality of temperature and heat flux are programmed in the numeric solution of the energy-conservation equation by considering the boundary of a very small, finite thickness and smoothing the temperature curve at every step of calculation.

  9. Petrophysical Properties of Twenty Drill Cores from the Los Azufres, Mexico, Geothermal Field

    SciTech Connect

    Iglesias, E.R.; Contreras L., E.; Garcia G., A.; Dominquez A., Bernardo

    1987-01-20

    For this study we selected 20 drill cores covering a wide range of depths (400-3000 m), from 15 wells, that provide a reasonable coverage of the field. Only andesite, the largely predominant rock type in the field, was included in this sample. We measured bulk density, grain (solids) density, effective porosity and (matrix) permeability on a considerable number of specimens taken from the cores; and inferred the corresponding total porosity and fraction of interconnected total porosity. We characterized the statistical distributions of the measured and inferred variables. The distributions of bulk density and grain density resulted approximately normal; the distributions of effective porosity, total porosity and fraction of total porosity turned out to be bimodal; the permeability distribution resulted highly skewed towards very small (1 mdarcy) values, though values as high as 400 mdarcies were measured. We also characterized the internal inhomogeneity of the cores by means of the ratio (standard deviation/mean) corresponding to the bulk density in each core (in average there are 9 specimens per core). The cores were found to present clearly discernible inhomogeneity; this quantitative characterization will help design new experimental work and interpret currently available and forthcoming results. We also found statistically significant linear correlations between total density and density of solids, effective porosity and total density, total porosity and total density, fraction of interconnected total porosity and the inverse of the effective porosity, total porosity and effective porosity; bulk density and total porosity also correlate with elevation. These results provide the first sizable and statistically detailed database available on petrophysical properties of the Los Azufres andesites. 1 tab., 16 figs., 4 refs.

  10. Prokaryotic and Eukaryotic Community Structure in Field and Cultured Microbialites from the Alkaline Lake Alchichica (Mexico)

    PubMed Central

    Couradeau, Estelle; Benzerara, Karim; Moreira, David; Gérard, Emmanuelle; Kaźmierczak, Józef; Tavera, Rosaluz; López-García, Purificación

    2011-01-01

    The geomicrobiology of crater lake microbialites remains largely unknown despite their evolutionary interest due to their resemblance to some Archaean analogs in the dominance of in situ carbonate precipitation over accretion. Here, we studied the diversity of archaea, bacteria and protists in microbialites of the alkaline Lake Alchichica from both field samples collected along a depth gradient (0–14 m depth) and long-term-maintained laboratory aquaria. Using small subunit (SSU) rRNA gene libraries and fingerprinting methods, we detected a wide diversity of bacteria and protists contrasting with a minor fraction of archaea. Oxygenic photosynthesizers were dominated by cyanobacteria, green algae and diatoms. Cyanobacterial diversity varied with depth, Oscillatoriales dominating shallow and intermediate microbialites and Pleurocapsales the deepest samples. The early-branching Gloeobacterales represented significant proportions in aquaria microbialites. Anoxygenic photosynthesizers were also diverse, comprising members of Alphaproteobacteria and Chloroflexi. Although photosynthetic microorganisms dominated in biomass, heterotrophic lineages were more diverse. We detected members of up to 21 bacterial phyla or candidate divisions, including lineages possibly involved in microbialite formation, such as sulfate-reducing Deltaproteobacteria but also Firmicutes and very diverse taxa likely able to degrade complex polymeric substances, such as Planctomycetales, Bacteroidetes and Verrucomicrobia. Heterotrophic eukaryotes were dominated by Fungi (including members of the basal Rozellida or Cryptomycota), Choanoflagellida, Nucleariida, Amoebozoa, Alveolata and Stramenopiles. The diversity and relative abundance of many eukaryotic lineages suggest an unforeseen role for protists in microbialite ecology. Many lineages from lake microbialites were successfully maintained in aquaria. Interestingly, the diversity detected in aquarium microbialites was higher than in field samples

  11. Depositional environments, diagenetic history, and porosity development, vacuum San Andres Field, Lea County, New Mexico

    SciTech Connect

    Robertson, J.W. )

    1990-02-01

    The Permian San Andres Formation was deposited in environments ranging from supratidal to subtidal, protected shallow marine to open shallow marine. Pelletoid-skeletal packstone/wackestone and pelletoid-oolite-skeletal packstone/grainstone facies of the composite subtidal, marine environments were concentrated in the southern half of the field where grainstone deposition was linked to a paleotopographic high. Deposition in the northern half of the field was dominated by the pelletoid wackestone/mudstone facies of the supratidal, restricted shallow-marine environment. Porosity is mainly diagenetic in origin. San Andres rocks passed through the marine phreatic, the mixed phreatic, the meteoric phreatic, and the deeper subsurface diagenetic environments. Matrix dolomitization in the marine and mixed-phreatic environment produced intercrystalline porosity in all the facies. Leaching of nondolomitized grains in the mixed phreatic and meteoric-phreatic environments created large moldic pores. Diagenetic patterns follow structural and depositional trends so that suites of characteristic pore types exist for each facies. Individual pore types consist of moldic, intergranular, intragranular, vuggy, and intercrystalline categories. Intercrystalline pores are present nearly everywhere, and predicting the abundance of moldic pores is the largest variable in predicting porosity values for a given stratigraphic interval. Highest porosity exists in the southern half of the study area where grainier facies were deposited on a paleotopographic high, and grains were partly dolomitized and subsequently were removed by leaching, leaving behind a composite intercrystalline-moldic pore network. Total porosity values do not correspond with facies boundaries, so porosity mapping was accomplished by dividing the San Andres into 20-ft-thick slices and computer contouring total porosity greater than 6% in each slice.

  12. Prokaryotic and eukaryotic community structure in field and cultured microbialites from the alkaline Lake Alchichica (Mexico).

    PubMed

    Couradeau, Estelle; Benzerara, Karim; Moreira, David; Gérard, Emmanuelle; Kaźmierczak, Józef; Tavera, Rosaluz; López-García, Purificación

    2011-01-01

    The geomicrobiology of crater lake microbialites remains largely unknown despite their evolutionary interest due to their resemblance to some Archaean analogs in the dominance of in situ carbonate precipitation over accretion. Here, we studied the diversity of archaea, bacteria and protists in microbialites of the alkaline Lake Alchichica from both field samples collected along a depth gradient (0-14 m depth) and long-term-maintained laboratory aquaria. Using small subunit (SSU) rRNA gene libraries and fingerprinting methods, we detected a wide diversity of bacteria and protists contrasting with a minor fraction of archaea. Oxygenic photosynthesizers were dominated by cyanobacteria, green algae and diatoms. Cyanobacterial diversity varied with depth, Oscillatoriales dominating shallow and intermediate microbialites and Pleurocapsales the deepest samples. The early-branching Gloeobacterales represented significant proportions in aquaria microbialites. Anoxygenic photosynthesizers were also diverse, comprising members of Alphaproteobacteria and Chloroflexi. Although photosynthetic microorganisms dominated in biomass, heterotrophic lineages were more diverse. We detected members of up to 21 bacterial phyla or candidate divisions, including lineages possibly involved in microbialite formation, such as sulfate-reducing Deltaproteobacteria but also Firmicutes and very diverse taxa likely able to degrade complex polymeric substances, such as Planctomycetales, Bacteroidetes and Verrucomicrobia. Heterotrophic eukaryotes were dominated by Fungi (including members of the basal Rozellida or Cryptomycota), Choanoflagellida, Nucleariida, Amoebozoa, Alveolata and Stramenopiles. The diversity and relative abundance of many eukaryotic lineages suggest an unforeseen role for protists in microbialite ecology. Many lineages from lake microbialites were successfully maintained in aquaria. Interestingly, the diversity detected in aquarium microbialites was higher than in field samples

  13. Mexico City, Mexico

    NASA Technical Reports Server (NTRS)

    1989-01-01

    In this rare clear view of Mexico City, Mexico (19.5N, 99.0W), the network of broad avenues and plazas of the capital city are very evident. The city, built on the remnants of a lake in the caldera of a tremendous extinct volcano, is home to over twenty million people and is slowly sinking as subsidence takes it's toll on the lakebed.

  14. Phytophthora capsici Epidemic Dispersion on Commercial Pepper Fields in Aguascalientes, Mexico

    PubMed Central

    Zapata-Vázquez, Adrián; Sánchez-Sánchez, Mario; del-Río-Robledo, Alicia; Silos-Espino, Héctor; Perales-Segovia, Catarino; Flores-Benítez, Silvia; González-Chavira, Mario Martín; Valera-Montero, Luis Lorenzo

    2012-01-01

    Chili pepper blight observed on pepper farms from north Aguascalientes was monitored for the presence of Phytophthora capsici during 2008–2010. Initially, ELISA tests were directed to plant samples from greenhouses and rustic nurseries, showing an 86% of positive samples. Later, samples of wilted plants from the farms during the first survey were tested with ELISA. The subsequent survey on soil samples included mycelia isolation and PCR amplification of a 560 bp fragment of ITS-specific DNA sequence of P. capsici. Data was analyzed according to four geographical areas defined by coordinates to ease the dispersal assessment. In general, one-third of the samples from surveyed fields contained P. capsici, inferring that this may be the pathogen responsible of the observed wilt. Nevertheless, only five sites from a total of 92 were consistently negative to P. capsici. The presence of this pathogen was detected through ELISA and confirmed through PCR. The other two-thirds of the negative samples may be attributable to Fusarium and Rhizoctonia, both isolated instead of Phytophthora in these areas. Due to these striking results, this information would be of interest for local plant protection committees and farmers to avoid further dispersal of pathogens to new lands. PMID:22629131

  15. Origin of late Quaternary dune fields on the Southern High Plains of Texas and New Mexico

    USGS Publications Warehouse

    Muhs, D.R.; Holliday, V.T.

    2001-01-01

    Mostly stabilized late Holocene eolian sands on the Southern High Plains of the United States were studied to determine their origins and to assess whether present dune stability depends more strongly on sediment supply, sediment availability, or transport limitations. Geomorphic, sedimentological, and geochemical trends indicate that late Holocene dunes formed under westerly paleowinds, broadly similar to those of today. Mineralogical and geochemical data indicate that the most likely source for the sands is not the Pecos River valley, but the Pleistocene Blackwater Draw Formation, an older, extensive eolian deposit in the region. These observations suggest that new sand is supplied whenever vegetation cover is diminished to the extent that the Blackwater Draw Formation can be eroded, in agreement with modern observations of wind erosion in the region. We conclude, therefore, that Southern High Plains dunes are stabilized primarily due to a vegetation cover. The dunes are thus sediment-availability limited. This conclusion is consistent with the observation that, in the warmest, driest part of the region (where vegetation cover is minimal), dunes are currently active over a large area. Geochemical data indicate that Southern High Plains dunes are the most mineralogically mature (quartz rich) sands yet studied in the Great Plains, which suggests a long history of eolian activity, either in the dune fields or during deposition of the Blackwater Draw Formation.

  16. EVALUATION OF THE FLOOD POTENTIAL OF THE SOUTH HOUSE (BLINEBRY) FIELD, LEA COUNTY, NEW MEXICO

    SciTech Connect

    L. Stephen Melzer

    2000-12-01

    /11 respectively. Production of oil and gas has been established with several months of production now available to make a reserve analysis. Production histories and reserves estimation are provided. An assessment of the flood potential for the South House project area has been completed with work concentrated on South House rock property and pay thickness characterization and analog studies. For the analogs, the North Robertson area, located twenty miles to the northeast, and the Teague Field, located 20 miles to the south, have been utilized due to their readily available database and previous waterflood studies. The South House area does appear to merit further examination as the rock quality compares favorably with both analog Fields; however, current well spacings of 40-acres will provide only marginal economics based upon $23.00/barrel oil prices. Permeability and porosity relationships are provided as a conditional demonstration that rock quality may be sufficient for successful waterflooding of the project area. Further rock property work and pay continuity studies are recommended.

  17. Predicting thermal conductivity of rocks from the Los Azufres geothermal field, Mexico, from easily measurable properties

    SciTech Connect

    Garcia, Alfonso; Contreras, Enrique; Dominquez, Bernardo A.

    1988-01-01

    A correlation is developed to predict thermal conductivity of drill cores from the Los Azufres geothermal field. Only andesites are included as they are predominant. Thermal conductivity of geothermal rocks is in general scarce and its determination is not simple. Almost all published correlations were developed for sedimentary rocks. Typically, for igneous rocks, chemical or mineral analyses are used for estimating conductivity by using some type of additive rule. This requires specialized analytical techniques and the procedure may not be sufficiently accurate if, for instance, a chemical analysis is to be changed into a mineral analysis. Thus a simple and accurate estimation method would be useful for engineering purposes. The present correlation predicts thermal conductivity from a knowledge of bulk density and total porosity, properties which provide basic rock characterization and are easy to measure. They may be determined from drill cores or cuttings, and the procedures represent a real advantage given the cost and low availability of cores. The multivariate correlation proposed is a quadratic polynomial and represents a useful tool to estimate thermal conductivity of igneous rocks since data on this property is very limited. For porosities between 0% and 25%, thermal conductivity is estimated with a maximum deviation of 22% and a residual mean square deviation of 4.62E-3 n terms of the log{sub 10}(k{rho}{sub b}) variable. The data were determined as part of a project which includes physical, thermal and mechanical properties of drill cores from Los Azufres. For the correlation, sixteen determinations of thermal conductivity, bulk density and total porosity are included. The conductivity data represent the first determinations ever made on these rocks.

  18. Generating rainfall fields using principal components (PC) decomposition of the covariance matrix: a case study in Mexico City

    NASA Astrophysics Data System (ADS)

    Bouvier, Christophe; Cisneros, Leonardo; Dominguez, Ramon; Laborde, Jean-Pierre; Lebel, Thierry

    2003-07-01

    Risk assessment and water resources management need to get a reliable estimation not only of the temporal distribution of the rainfall events, but also of their spatial extension. Data provided by dense rain gauges network or meteorological radar are generally not long enough to supply consistent information on a given area. Using Principal Components (PC) decomposition of the correlation matrix may generate rainfall fields, in order to expand or create available data. Features of the model ensure quick simulation, because the orthogonality of the eigenvectors of the correlation matrix allows separating the time and space generation. This model was applied to an 11 year daily rainfall sample of 49 raingauges, bounded within a rectangular frame of nearly 2500 km 2 around Mexico City. In order to account for seasonality effect, only rainfields from June to September were selected. The observed rainfields may have some important intermittence in space, since a lot of them do not cover more than half the reference area. First, it is shown that the distributions of the main characteristics of both the observed and generated rainfields are very close together, which means that the model is able to deal with spatial intermittence. Then, rainfields were generated using a better resolution grid (713 points instead of 49): the so-obtained rainfields feature more chaotic structures which could be coherent with what would be observed at a smaller scale on radar images, as it will be analyzed furthermore. So this kind of model could also suit for the spatial scaling effects. This model may be easily calibrated on the basis of both time-series at a given point and a correlation matrix. The former are generally readily available, the latter may be drawn from a short period where meteorological radar images are available. Furthermore, it could be applied to any given finite duration.

  19. Linking hydropedology and ecosystem services: differential controls of surface field saturated hydraulic conductivity in a volcanic setting in central Mexico

    NASA Astrophysics Data System (ADS)

    Gómez-Tagle, A.

    2009-03-01

    In this study the variation of field saturated soil hydraulic conductivity (Kfs) as key control variable and descriptor of infiltration was examined by means of a constant head single ring infiltrometer. The study took place in five coverage types and land uses in a volcanic setting in central Mexico. The tested hypothesis was that there exist a positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible controls of Kfs, for this volcanic setting. Land use history driven erosion plays a decisive role in subsurface horizon presence at the surface and soil matrix characteristic determination, while plant succession patterns seem to be strongly linked to soil bioturbation and preferential flow channel formation.

  20. Characterization of the temporal and spatial distribution and reproductive ratio of vesicular stomatitis outbreaks in Mexico in 2008.

    PubMed

    Arroyo, Montserrat; Perez, Andres M; Rodriguez, Luis L

    2011-02-01

    To characterize the temporal and spatial distribution and reproductive ratio of vesicular stomatitis (VS) outbreaks reported in Mexico in 2008. Bovine herds in Mexico in which VS outbreaks were officially reported and confirmed from January 1 through December 31, 2008. The Poisson model of the space-time scan statistic was used to identify periods and geographical locations at highest risk for VS in Mexico in 2008. The herd reproductive ratio (R(h)) of the epidemic was computed by use of the doubling-time method. 1 significant space-time cluster of VS was detected in the state of Michoacan from September 4 through December 10, 2008. The temporal extent of the VS outbreaks and the value and pattern of decrease of the R(h) were different in the endemic zone of Tabasco and Chiapas, compared with findings in the region included in the space-time cluster. The large number of VS outbreaks reported in Mexico in 2008 was associated with the spread of the disease from the endemic zone in southern Mexico to areas sporadically affected by the disease. Results suggested that implementation of a surveillance system in the endemic zone of Mexico aimed at early detection of changes in the value of R(h) and space-time clustering of the disease could help predict occurrence of future VS outbreaks originating from this endemic zone. This information will help prevent VS spread into regions of Mexico and neighboring countries that are only sporadically affected by the disease.

  1. Enhancing Diversity In The Geosciences; Intensive Field Experience In USA And Mexico For Middle And High School Teachers Serving Large Hispanic Populations.

    NASA Astrophysics Data System (ADS)

    Leal-Bautista, R. M.; Kitts, K. B.; Velazquez Oliman, G.; Perry, E. C.

    2008-12-01

    To encourage Hispanic participation and enrolment in the geosciences and ultimately enhance diversity within the discipline, we recruited ten middle and high school science teachers serving large Hispanic populations (60-97%) for a paid three-week field experience supported by an NSF Opportunities for Enhancing Diversity in the Geosciences grant. In 2006, the field experiences focused on volcanic events and the water problems of the Central part of Mexico. In 2008, the field experiences focused on karstic and hydrogeological conditions of the Yucatan Peninsula. In addition to the geological aspects of the fieldwork experience, the trip to Mexico exposed the teachers to a social environment outside of their community where they interacted with a diverse group of scientists from the Universidad National Autonoma de Mexico (UNAM), Centro de Investigacion Cientifica de Yucatan (CICY) and Centro Nacional de Desastres (CENAPRED). A key part of this project was the encounter between American and Mexican teachers that included a day of presentations, panel discussion and some class-room activities. Direct interaction between the cooperating teachers and the American and Mexican geoscientists provided actual scientific research experiences to educate and to help dispel misconceptions the teachers themselves may have had about who geoscientists really are and what they do. Teachers of the 2006 group produced educational materials from their field experiences and presented these materials at professional conferences. We measured the efficacy of these activities quantitatively via pre- and post-tests assessing confidence levels, preconceptions and biases, NIU staff observations of participants in their home institutions, and evaluations of participants' field books and pedagogical materials. We present these data here and identify specific activities that are both effective and efficient in changing teacher behaviours and attitudes enabling them to better connect with their

  2. Eruptive History of the Rhyolitic Guangoche Volcano, Los Azufres Volcanic Field, Central Mexico

    NASA Astrophysics Data System (ADS)

    Rangel Granados, E.; Arce, J. L.; Macias, J. L.; Layer, P. W.

    2014-12-01

    Guangoche is a rhyolitic and polygenetic volcano with a maximum elevation of 2,760 meters above sea level. It is situated to the southwest of the Los Azufres Volcanic Field (LAVF), in the central sector of the Trans-Mexican Volcanic Belt. Guangoche volcano is the youngest volcano described within the LAVF. It shows a horseshoe shaped crater open to the south, with a central lava dome. Its eruptive history during late Pleistocene has been intense with six explosive eruptions that consists of: 1) A southwards sector collapse of the volcano that generated a debris avalanche deposit with megablocks of heterogenous composition; 2) A plinian-type eruption that generated a pumice fall deposit and pyroclastic density currents by column collapse at 30.6 ka; 3) A plinian-type eruption "White Pumice Sequence" (29 ka) that developed a 22-km-high eruptive column, with a MDR of 7.0 x 107 kg/s (vol. = 0.53 km3); 4) A dome-destruction event, "Agua Blanca Pyroclastic Sequence" at 26.7 ka, that deposited a block-and-ash flow deposit; 5) A subplinian-plinian type eruption "Ochre Pyroclastic Sequence" (<26 ka) with an important initial phreatomagmatic phase, that generated pyroclastic density currents and pumice fallouts. The subplinian-plinian event generated a 16-km-high eruptive column, with a MDR of 1.9 x 107 kg/s, and magma volume of 0.38 km3; 6) The eruptive history ended with a subplinian eruption (<<26 ka), that generated a multilayered fall deposit, that developed a 11-km-high eruptive column, with a MDR of 2.9 x 106 kg/s and a magma volume of 0.26 km3. Volcanic activity at Guangoche volcano has been intense and future activity should not be discarded. Unfortunately, the last two events have not been dated yet. Guangoche rhyolitic magma is characterized by low-Ba contents suggesting crystal mush extraction for their genesis.

  3. The Significance of Acid Alteration in the Los Humeros High-Temperature Geothermal Field, Puebla, Mexico.

    NASA Astrophysics Data System (ADS)

    Elders, W. A.; Izquierdo, G.

    2014-12-01

    The Los Humeros geothermal field is a high-enthalpy hydrothermal system with more than 40 drilled deep wells, mostly producing high steam fractions at > 300oC. However, although it has a large resource potential, low permeability and corrosive acid fluids have hampered development so that it currently has an installed electrical generating capacity of only 40 MWe. The widespread production of low pH fluids from the reservoir is inconsistent with the marked absence in the reservoir rocks of hydrothermal minerals typical of acid alteration. Instead the hydrothermal alteration observed is typical of that due to neutral to alkaline pH waters reacting with the volcanic rocks of the production zones. Thus it appears that since the reservoir has recently suffered a marked drop in fluid pressure and is in process of transitioning from being water-dominated to being vapor-dominated. However sparse examples of acid leaching are observed locally at depths of about 2 km in the form of bleached, intensely silicified zones, in low permeability and very hot (>350oC) parts of reservoir. Although these leached rocks retain their primary volcanic and pyroclastic textures, they are altered almost entirely to microcrystalline quartz, with some relict pseudomorphs of plagioclase phenocrysts and traces of earlier-formed hydrothermal chlorite and pyrite. These acid-altered zones are usually only some tens of meters thick and deeper rocks lack such silicification. The acid fluids responsible for their formation could either be magmatic volatiles, or could be formed during production (e.g. reaction of water and salts forming hydrogen chloride by hydrolysis at high temperatures). The very high boron content of the fluids produced by the Los Humeros wells suggests that their ultimate source is most likely magmatic gases. However, these acid gases did not react widely with the rocks. We suggest that the silicified zones are forming locally where colder descending waters are encountering

  4. A Mechanical Model for the Michoacan Subduction Zone and Associated Intra-Arc Extension

    NASA Astrophysics Data System (ADS)

    Contreras, J. J.

    2006-12-01

    The Trans-Mexican volcanic belt is a subduction-related arc dissected by a field of seismically active normal faults clustered in its western part. This field of normal faults is an enigmatic feature of the Trans-Mexican volcanic belt and the nature of the mechanism driving extension has been the subject of debate for more than 25 years. These faults form en echelon arrays and systems of nested faults aligned parallel to the axis of the volcanic belt with a characteristic width of 20 km. Fault arrays seldom exceed 30 km in length and examples include the Tepic-Zoacalco, Chapala, and Morelia-Acambay fault zones. Moreover, crosscutting relations with basalt flows indicate that these faults started to accrue displacement at 5-6 My during a period of high convergence rate between the North America and Rivera plates. The model consists of a 40 km-thick elastic plate (i.e., the North America plate) sitting on top of Newtonian incompressible fluid (upper mantle) forced in convection along the Wadati-Benioff zone. The plate is allowed to undergo plasticity when deviatoric stresses exceed the Mohr-Coulomb yield strength. The thermal state of the subduction zone is also incorporated in the model, given the strong dependence of the rehology of both mantle and crust on temperature. Boundary conditions of the model are consistent with heat-flow measurements, gravity modeling, convergence rates derived from sea-floor magnetic anomalies, as well as geological and seismological observations. Model shows that extension in the arc is the direct result of subduction due to viscous coupling between tectonic plates. Numerical solutions indicate that positive changes in momentum of the Rivera plate increase viscous drag along the base and leading edge of North America resulting in downward bending of the continental plate. This gives rise to tension 100-200 km inland from the trench in good agreement with the location of the active normal faults of the western Trans-Mexican volcanic

  5. The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

    NASA Astrophysics Data System (ADS)

    Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

    2014-05-01

    The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

  6. Measurements of submicron aerosols at the California-Mexico border during the Cal-Mex 2010 field campaign

    NASA Astrophysics Data System (ADS)

    Levy, Misti E.; Zhang, Renyi; Zheng, Jun; Tan, Haobo; Wang, Yuan; Molina, Luisa T.; Takahama, S.; Russell, L. M.; Li, Guohui

    2014-05-01

    We present measurements of submicron aerosols in Tijuana, Mexico during the Cal-Mex 2010 field campaign. A suite of aerosol instrumentations were deployed, including a hygroscopic-volatility tandem differential mobility analyzer (HV-TDMA), aerosol particle mass analyzer (APM), condensation particle counter (CPC), cavity ring-down spectrometer (CRDS), and nephelometer to measure the aerosol size distributions, effective density, hygroscopic growth factors (HGF), volatility growth factors (VGF), and optical properties. The average mass concentration of PM0.6 is 10.39 ± 7.61 μg m-3, and the derived average black carbon (BC) mass concentration is 2.87 ± 2.65 μg m-3. There is little new particle formation or particle growth during the day, and the mass loading is dominated by organic aerosols and BC, which on average are 37% and 27% of PM1.0, respectively. For four particle sizes of 46, 81, 151, and 240 nm, the measured particle effective density, HGFs, and VGFs exhibit distinct diurnal trends and size-dependence. For smaller particles (46 and 81 nm), the effective density distribution is unimodal during the day and night, signifying an internally mixed aerosol composition. In contrast, larger particles (151 and 240 nm) exhibit a bi-modal effective density distribution during the daytime, indicating an external mixture of fresh BC and organic aerosols, but a unimodal distribution during the night, corresponding to an internal mixture of BC and organic aerosols. The smaller particles show a noticeable diurnal trend in the effective density distribution, with the highest effective density (1.70 g cm-3) occurring shortly after midnight and the lowest value (0.90 g cm-3) occurring during the afternoon, corresponding most likely to primary organic aerosols and BC, respectively. Both HGFs and VGFs measured are strongly size-dependent. HGFs increase with increasing particle size, indicating that the largest particles are more hygroscopic. VGFs decrease with increasing

  7. 40Ar/39Ar dating of the Quaternary Chichinautzin Volcanic Field, south of Mexico City: Implications for timing, effusion rate, and distribution of the volcanism

    NASA Astrophysics Data System (ADS)

    Arce, J. L.; Layer, P. W.; Lassiter, J. C.; Benowitz, J.; Ramirez, J.; Macias, J. L.

    2013-05-01

    Monogenetic structures located at the southern and western ends of the Chichinautzin Volcanic Field (Trans-Mexican Volcanic Belt, central Mexico) yielded 40Ar/39Ar ages ranging from 1.2 Ma in the west to 1.0-0.09 Ma in the south, which are older than the <0.004 Ma previously established for the entire volcanic field. These new ages indicate: (1) an eruption rate of 0.47km3/1000 yr, which is much lower than the 11.7 km3/1000 yr previously estimated; (2) that the monogenetic Chichinautzin magmatism coexisted with the Zempoala (0.7 Ma) and La Corona (1.0 Ma) polygenetic volcanoes on the southern edge of Las Cruces Volcanic Range (southern Trans-Mexican Volcanic Belt); and (3) confirm that the drainage system between the Mexico and Cuernavaca basins was closed during early Pleistocene forming the Texcoco Lake. Whole-rock chemistry and Sr, Nd, and Pb isotopic data indicate that heterogeneous magmatism has been throughout the life of Chichinautzin, probably due to slab and sediment contributions to the mantle wedge plus contamination and fractional crystallization. The overall Pleistocene magmatism at the Chichinautzin Volcanic Field has undergone a higher eruption rate if compared to other volcanic fields of the Trans-Mexican Volcanic Belt. This could be due to a combination of variable subduction rates of the Rivera and Cocos plates along the Middle America Trench, to different distances from the trench, and the depth to the subducted slab

  8. Petrogenesis and metal budget of Pelagatos volcano in the Chichinautzin monogenetic field, Mexico: A Melt Inclusion Study

    NASA Astrophysics Data System (ADS)

    Roberge, J.; Mercer, C. N.; Kent, A. J.; Guilbaud, M.

    2013-12-01

    Melt inclusions are now widely used to quantify pre-eruptive volatile contents and to track the compositional evolution of magma. In recent years, the use of melt inclusions has also increased markedly for research in economic geology. Melt inclusions are becoming a powerful tool to track metal contents in ore-forming magmatic reservoirs and metals like Ag, Cu, Li, Mo, Sn, Pb, W, Zn are now commonly included in trace element analyses. Investigating metal reservoirs in currently active volcanic systems provides insight into the conditions that favor mineralization in ore-forming deposits compared to barren systems. In this work, we present volatiles (H2O, CO2, S, Cl) and major and trace element contents of olivine-hosted melt inclusion from 4 samples spanning the entire eruption of Pelagatos scoria cone. Pelagatos is a small and young (less than 14 000 years B.P.) monogenetic volcano within the Sierra Chichinautzin volcanic field located in the central portion of the Trans Mexican Volcanic Belt (south-east of Mexico City). The melt inclusions are basaltic andesite to andesite in composition, with 1.84 - 6.02 wt% MgO, 51.95 - 59.21 wt% SiO2 and 0.64 - 1.55 wt% K2O. The H2O varies from 0.5 to 4.3 wt% whereas CO2 varies from below detection up to 976 ppm. Sulfur contents vary from 35 to 1451 ppm, showing a decrease with increasing MgO content suggesting that S is being lost with progressive differentiation, but since S concentrations do not correlate with any other gas phase (H2O, CO2, Cl) we hypothesize that it partitioned into an immiscible fluid or mineral phase. On the other hand, Cl contents are broadly constant (900 to 1267 ppm), and shows no correlation with MgO or K2O. All analyzed metals (Ag, Cu, Li, Mo, Sn, Pb, W, Zn ) behave incompatibly showing a positive correlation with La. Cu (18 to 82 ppm), Pb (2 to 8 ppm) Zn (30 to 107 ppm) and Mo correlate positively together indicating that fractional crystallization concentrates these elements. These results provide

  9. Oceanic gamefish/Skylab project field operating plan for operations 4, 5 August. [in Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The operation plans are presented for the oceanic Gamefish/Skylab Experiment 240, which was conducted to obtain fish catch data for the northeast area of the Gulf of Mexico. The plans for surface measurements, aerial observations, and communications are included.

  10. Aflatoxin-producing fungi in maize fields of Sonora Mexico at varying elevations: a three year study

    USDA-ARS?s Scientific Manuscript database

    Aflatoxin contamination of maize, a critical staple of billions, by Aspergillus flavus is a recurrent problem in the tropics and subtropics. Maize is produced across a broad range of elevations in the state of Sonora, Mexico. The current study evaluated the influence of elevation on the composition ...

  11. 40Ar/39Ar dating, geochemistry, and isotopic analyses of the quaternary Chichinautzin volcanic field, south of Mexico City: implications for timing, eruption rate, and distribution of volcanism

    NASA Astrophysics Data System (ADS)

    Arce, J. L.; Layer, P. W.; Lassiter, J. C.; Benowitz, J. A.; Macías, J. L.; Ramírez-Espinosa, J.

    2013-12-01

    Monogenetic structures located at the southern and western ends of the Chichinautzin volcanic field (Trans-Mexican Volcanic Belt, Central Mexico) yield 40Ar/39Ar ages ranging from 1.2 Ma in the western portion of the field to 1.0-0.09 Ma in the southern portion, all of which are older than the <0.04 Ma age previously established for the entire volcanic field. These new ages indicate: (1) an eruption rate of 0.47 km3/kyr, which is much lower than the 11.7 km3/kyr previously estimated; (2) that the Chichinautzin magmatism coexisted with the Zempoala (0.7 Ma) and La Corona (1.0 Ma) polygenetic volcanoes on the southern edge of Las Cruces Volcanic Range (Trans-Mexican Volcanic Belt); and confirm (3) that the drainage system between the Mexico and Cuernavaca basins was closed during early Pleistocene forming the Texcoco Lake. Whole-rock chemistry and Sr, Nd, and Pb isotopic data indicate heterogeneous magmatism throughout the history of Chichinautzin activity that likely reflects variable degrees of slab and sediment contributions to the mantle wedge, fractional crystallization, and crustal assimilation. Even with the revised duration of volcanism within the Chichinautzin Volcanic Field, its eruption rate is higher than most other volcanic fields of the Trans-Mexican Volcanic Belt and is comparable only to the Tacámbaro-Puruaran area in the Michoacán-Guanajuato Volcanic Field to the west. These variations in eruption rates among different volcanic fields may reflect a combination of variable subduction rates of the Rivera and Cocos plates along the Middle America Trench, as well as different distances from the trench, variations in the depth with respect to the subducted slab, or the upper plate characteristics.

  12. Finite-fault analysis of the 1979 March 14 Petatlan, Mexico, earthquake using teleseismic P waveforms

    USGS Publications Warehouse

    Mendoza, C.

    1995-01-01

    Vertical, teleseismic P waves recorded for the 1979 March 14 Petatlan, Mexico, earthquake were used to derive the distribution of coseismic slip using a linear finite-fault inversion scheme that solves for the amount of slip in each of a series of consecutive time windows. The coseismic slip inferred from the P waves shows a small 70 cm peak near the earthquake hypocentre and a large zone of dislocation (1.2 m maximum) further south-east. The slip pattern covers depths from 3 to 25 km and is located south-east of other recent large interplate ruptures on the Michoacan segment of the Mexican subduction zone. This result indicates that the 1979 Petatlan earthquake broke an independent, adjacent portion of the Cocos-North America plate boundary. -from Author

  13. Tracing the movement and storage of magma in the crust through seismology: Examples from Alaska and western Mexico

    NASA Astrophysics Data System (ADS)

    Gardine, Matthew D.

    Four studies are presented that examine magma movement and storage in the crust using seismology at three different volcanoes: Fourpeaked volcano in the Cook Inlet region of Alaska, Paricutin volcano in the Michoacan-Guanajato volcanic field in western Mexico, and Colima volcano at the western edge of the Trans-Mexican Volcanic Belt. In 2006, Fourpeaked volcano, Alaska, had a widely-observed phreatic eruption. A modest seismic network was installed in stages following the unrest. The eruption was followed by several months of sustained seismicity punctuated by vigorous swarms and SO2 emissions exceeding a thousand tons/day. Based on the history of Fourpeaked, and observations during and after the phreatic eruption, it is proposed that the activity was caused by a modest injection of new magma beneath the volcano. Also presented are a series of studies from western Mexico, an area of high seismic and volcanic activity. A description of the creation of an automatically generated regional catalog of seismic activity is presented, along with a comparison with existing seismicity studies of the area. From this catalog, a swarm of earthquakes near Parfcutin in May-June 2006 was discovered. This swarm demonstrated a steady upward migration in depth with time. Focal mechanisms during the first part of the swarm reflect the increased stress caused by dike inflation. In early June, the stress orientation changed and became more consistent with the inflation of a horizontal sill-like structure. At Colima volcano, a P-wave tomographic inversion using arrivals from 299 regional earthquakes is presented. The results of the inversion show two distinct low-velocity zones. One is in the upper 10 km under the volcano and may be caused by a magma chamber-type structure. The second anomaly, with peak values of 2.5% slower velocities, was imaged in the crust southeast of the volcano at depths of 15-30 km. This body may be due to partial melt and increased temperatures from a second

  14. Effectiveness of natural treatment in a wastewater irrigation district of the Mexico City region: A synoptic field survey

    SciTech Connect

    Downs, T.J.; Cifuentes, E.; Ruth, E.; Suffet, I.

    2000-02-01

    Untreated wastewater from Mexico City has been used for decades to irrigate the Mezquital Valley, Hidalgo, Mexico. A synoptic survey of the natural treatment systems was carried out using the criteria of 24 trace metals, 67 target base/neutral/acid (BNA) semivolatile organic compounds, nontarget BNA semivolatile organics, nitrate, 23 chlorinated pesticides, and a 20 congener polychlorinated biphenyl (PCB) suite. Data suggest the irrigation region is acting as a huge open-system slow sand filter, the main reservoir as a large waste stabilization lagoon, and he canals as extremely long, narrow stabilization channels. The BNA levels in surface water (SW) after reservoir retention were much lower than before it, while levels in groundwater (GW) were significantly lower than SW. All GW nitrate levels exceeded them for only a few metals. Low to moderate levels of organochlorine pesticides and PCBs were found.

  15. LIDAR Observations of the Vertical Ozone and Aerosol Distribution over Mexico City during the MCMA-2003 Field Campaign

    NASA Astrophysics Data System (ADS)

    Simeonov, V.; Ristori, P.; Taslakov, M.; Dinoev, T.; van den Bergh, H.; Frey, S.; Molina, L. T.; Molina, M. J.

    2004-12-01

    An international field measurement campaign was held in April - May 2003 in the Mexico City Metropolitan Area (MCMA) as part of an effort to understand the complex urban air pollution problems in large cities. Gas phase and aerosol constituents were studied intensively during the campaign. LIDAR played an important role for measuring boundary layer dynamics and photochemical processes by monitoring the vertical distribution of aerosols and ozone. Two elastic DIAL and one Raman DIAL for ozone measurements were operated quasi-simultaneously during the campaign at the CENICA super site. The lidar of the Swiss Federal Institute of Technology, Lausanne (EPFL), Switzerland is an elastic three-wavelength UV DIAL combined with an aerosol lidar at 532 nm with an operational range of 200-6000 m for ozone measurements and 200-10000 m for aerosol measurements. The other elastic system is a commercial, stand alone two-wavelength DIAL produced and operated by ELIGHT Laser Systems GmbH. It performed ozone measurements from 400 to 2000 m. A combined Raman DIAL and aerosol Raman system was on loan from Freie Universität Berlin. This instrument was operated by the MIT team and provided ozone concentration from 350 to 2600 m and multicolor aerosol backscatter, Raman and depolarization. The campaign was designed to cover the height of the annual photochemical season. Rain episodes during the afternoons and the evenings at the beginning of the campaign caused discontinuity in the observation. Improved meteorological conditions from April 25 to May 3 made continuous measurements of all participating Lidars possible. A cloud-topped boundary layer (BL) was the frequently observed in the afternoon during this period. The top of the BL estimated from the aerosol measurements showed steady day-to-day increase, reaching altitudes of up to 4 km, comparable to the altitudes of the surrounding mountains. An obvious detachment of the top of the BL was also observed by the EPFL Lidar during the

  16. Orgin and significance of geochemical variability among oils and gas-condensates in the Tiger Shoal Field, northern Gulf of Mexico

    SciTech Connect

    Kelley, P.A.; Imbus, S.W.; McKeever, S.R.

    1995-12-31

    Geochemical data placed in geological context is key to understanding the processes controlling the variability of oils and gas-condensates in the Tiger Shoal Field, northern Gulf of Mexico. Thermal maturity at generation and phase partitioning are the principal processes accounting for variability in the bulk and molecular properties of the oils and gas-condensates. Quantification of the extent that these processes altered the oils and gas-condensates between fault blocks and among individual sands permits: (1) documentation of the most effective migration conduits, (2) inference of deeper or shallower pay zones, (3) and assessment of vertical and lateral fluid connectivity. Calibration of bulk to molecular properties will permit rapid assessment of the type and extent of alteration using basic parameters such as API gravity and gas oil ratio (GOR). Upon mass balancing with initial reserves data, a detailed risking scheme for remaining prospects within the field can be formulated.

  17. Surface Deformation Associated with Geothermal Fluids Extraction at the Cerro Prieto Geothermal Field, Baja California, Mexico Revealed by DInSAR Technique

    NASA Astrophysics Data System (ADS)

    Sarychikhina, O.; Glowacka, E.; Mojarro, J.

    2016-08-01

    The Differential Synthetic Aperture Radar Interferometry (DInSAR) is widely used for surface deformation detection and monitoring.In this paper, ERS-1/2, ENVISAT and RADARSAT-2 synthetic aperture radar (SAR) images acquired between 1993 and 2014 were processed to investigate the evolution of surface deformation at the Cerro Prieto geothermal field, Baja California, Mexico. The conventional DInSAR together with the interferogram stacking method was applied. Average LOS (line of sight) displacement velocity maps were generated for different periods: 1993 - 1997, 1998 - 2000, 2004, 2005, 2007, 2009, and 2012 - 2014, revealing that the area corresponding to Cerro Prieto basin presented the important surface deformation (mainly subsidence) during the entire time of investigation. The changes in the surface deformation pattern and rate were identified. These changes have a good correlation in time with the changes of production in the Cerro Prieto geothermal field.

  18. Ancient seismic record of the Tarascan (Purhepecha) Empire. Preclasic Period (3000 Yr B.P.). Jaracuaro Island, Patzcuaro Lake. Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez Pascua, Miguel Angel; Garduño-Monroy, Victor Hugo; Perez-Lopez, Raul; Israde-Alcantara, Isabel

    2010-05-01

    The Pátzcuaro lake is located in the Mexican State of Michoacán in the Transmexican Volcanic Belt. The Jarácuaro island is formed by Holocene lake sediments highly deformed by active faults (Morelia-Acambay Fault System, MAFS, more than 200 km long). MAFS is an E-W strike-slip fault with a transtensive component in the Pázcuaro Lake zone. Several paleoseismic studies were carried out in the island. Four trenches were made in the active faults that cross the island and it is possible observe that there are two andesitic blocks (>4 m3) over two different faults with surface rupture. The archaeological evidences (pottery, idols, etc), founded in the soils affected by the fault, implies that the age of the events concern to the Pre - Classic period (3.000 years B.P.).The Tarascan (or Purhépecha) Empire supported this earthquakes and put the blocks close both faults on the hanging wall block. The andesitic blocks are carved and polished and the quarry where this blocks were extracted is 1.5 km long out the lake. This cultural behaviour was profusely used by the Tarascan related to natural disasters but not documented before related to earthquakes. Maybe this is ones of the oldest human seismic manifestation, and is the first time that is connected a fault with a seismic movement.

  19. Counterclockwise rotations in the Late Eocene-Oligocene volcanic fields of San Luis Potosí and Sierra de Guanajuato (eastern Mesa Central, Mexico)

    NASA Astrophysics Data System (ADS)

    Andreani, Louis; Gattacceca, Jerôme; Rangin, Claude; Martínez-Reyes, Juventino; Demory, François

    2014-12-01

    We used paleomagnetic and structural data to investigate the late Eocene-Oligocene tectonic evolution of the Mesa Central area in Mexico. The Mesa Central was affected by NW-trending faults (Tepehuanes-San Luis fault system) coeval with a Late Eocene-Oligocene ignimbrite flare-up and by post-27 Ma NNE-trending grabens related to the Basin and Range. We obtained reliable paleomagnetic directions from 61 sites within the Late Eocene-Oligocene volcanic series (~ 30 to ~ 27 Ma) of the San Luis Potosí volcanic field and Sierra de Guanajuato. For each site we also measured the anisotropy of magnetic susceptibility (AMS). Tilt corrections were made using AMS data for 33 sites where in situ bedding measurements were not available. Paleomagnetic directions indicate counterclockwise rotations of about 10° with respect to stable North America after 30-25 Ma. Structural data suggest that the volcanic succession was mainly affected by normal faults. However, we also found evidences for oblique or horizontal striae showing a left-lateral component along NW-trending faults and a right lateral component along NE-trending faults. Both motions are consistent with a N-S extension oblique to the Tepehuanes-San Luis fault system. Previous paleomagnetic studies in northern and southern Mexico show the prevalence of minor left-lateral shear components along regional-scale transpressional and transtensional lineaments. Our paleomagnetic data may reflect thus small vertical-axis rotations related to a minor shear component coeval with the Oligocene intra-arc extension in central Mexico.

  20. Distribution, Magnitudes, Reactivities, Ratios and Diurnal Patterns of Volatile Organic Compounds in the Valley of Mexico During the MCMA 2002 & 2003 Field Campaigns

    SciTech Connect

    Velasco, E.; Lamb, Brian K.; Westberg, Halvor; Allwine, Eugene J.; Sosa, G.; Arriaga-Colina, J. L.; Jobson, B. T.; Alexander, M. Lizabeth; Prazeller, Peter; Knighton, Walter B.; Rogers, T.; Grutter, M.; Herndon, S.; Kolb, C. E.; Zavala, Mary A.; de Foy, B.; Volkamer, Rainer M.; Molina, Luisa; Molina, Mario J.

    2007-01-23

    A wide array of volatile organic compound (VOC) measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Four distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID), on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS), continuous real-time detection of olefins using a Fast Olefin Sensor (FOS), and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS). The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC) was dominated by alkanes (60%), followed by aromatics (15%) and olefins (5%). The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc.) and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1, 3-butadiene, benzene, toluene and xylenes, were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic in addition to meteorological processes. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other photochemical air

  1. Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 & 2003 field campaigns

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Lamb, B.; Westberg, H.; Allwine, E.; Sosa, G.; Arriaga-Colina, J. L.; Jobson, B. T.; Alexander, M. L.; Prazeller, P.; Knighton, W. B.; Rogers, T. M.; Grutter, M.; Herndon, S. C.; Kolb, C. E.; Zavala, M.; de Foy, B.; Volkamer, R.; Molina, L. T.; Molina, M. J.

    2007-01-01

    A wide array of volatile organic compound (VOC) measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Four distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID), on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS), continuous real-time detection of olefins using a Fast Olefin Sensor (FOS), and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS). The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC) was dominated by alkanes (60%), followed by aromatics (15%) and olefins (5%). The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc.) and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1,3-butadiene, benzene, toluene and xylenes, were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic in addition to meteorological processes. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other photochemical air

  2. Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 and 2003 field campaigns

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Lamb, B.; Westberg, H.; Allwine, E.; Sosa, G.; Arriaga-Colina, J. L.; Jobson, B. T.; Alexander, M.; Prazeller, P.; Knighton, W. B.; Rogers, T. M.; Grutter, M.; Herndon, S. C.; Kolb, C. E.; Zavala, M.; de Foy, B.; Volkamer, R.; Molina, L. T.; Molina, M. J.

    2006-08-01

    A wide array of volatile organic compound (VOC) measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Five distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID), on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS), continuous real-time detection of olefins using a Fast Olefin Sensor (FOS), and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS). The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC) was dominated by alkanes (60%), followed by aromatics (15%) and olefins (5%). The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc.) and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1,3-butadiene, benzene, toluene and xylenes were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other photochemical air quality modeling studies suggests that

  3. Evolution of the Latir volcanic field, Northern New Mexico, and its relation to the Rio Grande Rift, as indicated by potassium-argon and fission track dating

    NASA Astrophysics Data System (ADS)

    Lipman, Peter W.; Mehnert, Harald H.; Naeser, Charles W.

    1986-05-01

    Remnants of the Latir volcanic field and cogenetic plutonic rocks are exceptionally exposed along the east margin of the present-day Rio Grande rift by topographic and structural relief in the Sangre de Cristo Mountains of northern New Mexico. Evolution of the magmatic system associated with the Latir field, which culminated in eruption of a regional ash flow sheet (the Amalia Tuff) and collapse of the Questa caldera 26 m.y. ago, has been documented by 74 new potassium-argon (K-Ar) and fission track (F-T) ages. The bulk of the precaldera volcanism, ash flow eruptions and caldera formation, and initial crystallization of the associated shallow granitic batholith took place between 28 and 25 Ma; economically important molybdenum mineralization is related to smaller granitic intrusions along the south margin of the Questa caldera at about 23 Ma. Interpretation of the radiogenic ages within this relatively restricted time span is complicated by widespread thermal resetting of earlier parts of the igneous sequence by later intrusions. Many samples yielded discordant ages for different mineral phases. Thermal blocking temperatures decrease in the order: K-Ar sanidine > K-Ar biotite > F-T zircon ≫ F-T apatite. The F-T results are especially useful indicators of cooling and uplift rates. Upper portions of the subvolcanic batholith, that underlay the Questa caldera, cooled to about 100°C within about a million years of emplacement; uplift of the batholith increases to the south along this segment of the Sangre de Cristo Mountains. Activity in the Latir volcanic field was concurrent with southwest directed extension along the early Rio Grande rift zone in northern New Mexico and southern Colorado. The geometry of this early rifting is compatible with interpretation as back arc extension related to a subduction system dipping gently beneath the cordilleran region of the American plate. The Latir field lies at the southern end of a southward migrating Tertiary magmatic

  4. Changes in Microbial and Phytoplankton Communities in Response to Oil and Nutrients in the Northern Gulf of Mexico: Correlating Experiments With Field Observations.

    NASA Astrophysics Data System (ADS)

    D'Souza, N.; Weber, S.; Subramaniam, A.; Juhl, A. R.; Montoya, J. P.

    2016-02-01

    Natural hydrocarbon seeps account for around 47% of the oil released into the environment, with seeps in the Gulf of Mexico releasing up to 1.1×108 L oil year-1. Our previous work in the Gulf of Mexico has linked natural hydrocarbon seepage occurring at depths exceeding 1000 meters to elevations in surface and sub-surface chlorophyll concentrations in the upper water column via plume-driven upwelling of nutrient rich waters from depth. Subsequent experiments further revealed synergistic impacts of oil, nutrients, and microbial predation on surface microbial growth rates and metabolism - suggesting an additional top-down control on surface bacteria and microbes. While the magnitude of each contribution remains unclear, both, bottom-up and top-down mechanisms associated with natural oil seepage are evident. We build on our previous findings with results from microcosm experiments aimed at dissecting out the influence of nitrate, phosphate, silica, and crude oil on microbes in surface waters. Changes in phytoplankton populations, bacterial growth rates, and the subsequent drawdown of nutrients in these microcosms are presented here in context of field measurements made at natural seeps.

  5. Numerical recognition of alignments in monogenetic volcanic areas: Examples from the Michoacán-Guanajuato Volcanic Field in Mexico and Calatrava in Spain

    NASA Astrophysics Data System (ADS)

    Cebriá, J. M.; Martín-Escorza, C.; López-Ruiz, J.; Morán-Zenteno, D. J.; Martiny, B. M.

    2011-04-01

    Identification of geological lineaments using numerical methods is a useful tool to reveal structures that may not be evident to the naked eye. In this sense, monogenetic volcanic fields represent an especially suitable case for the application of such techniques, since eruptive vents can be considered as point-like features. Application of a two-point azimuth method to the Michoacán-Guanajuato Volcanic Field (Mexico) and the Calatrava Volcanic Province (Spain) demonstrates that the main lineaments controlling the distributions of volcanic vents (~ 322° in Calatrava and ~ 30° in Michoacán) approach the respective main compressional axes that dominate in the area (i.e. the Cocos-North America plates convergence and the main Betics compressional direction, respectively). Considering the stress fields that are present in each volcanic area and their respective geodynamic history, it seems that although volcanism may be a consequence of contemporaneous extensional regimes, the distribution of the volcanic vents in these kinds of monogenetic fields is actually controlled by reactivation of older fractures which then become more favourable for producing space for magma ascent at near-surface levels.

  6. Immediate Identification of Volcanic Eruption Intensity: Promising Test of a New Monitoring System Based on Short-Term Electrostatic Field Variations at the Active Volcano Popocatepetl, Mexico

    NASA Astrophysics Data System (ADS)

    Berger, P.

    2006-12-01

    Experiments by the Physikalisch Vulkanologisches Labor (PVL) in Wuerzburg, Germany, have shown that the intensity of violent volcanic eruptions, occurring when magma undergoes brittle fragmentation, is mirrored within brief electrical charges that can be detected on a short timescale (ms). Laboratory studies and certain explosion experiments offer the opportunity to calibrate the energy release of volcanic eruptions. Based on these results, a new high-precision, low-cost, real-time surveillance system is developed and tested at the active volcano of Popocatepetl, Mexico. This volcano, situated about 60 km southeast of Mexico City, offers excellent testing conditions, erupting regularly and intensively. The system, which detects short-term electrostatic field gradients (dc voltage against local ground), mainly consists of an antenna and a specially- designed amplifier. Depending on eruption intensity, as little as two or three eruptions will provide a sufficient amount of data. Amount, size, and shape of erupted particles give important indications about the physical fragmentation process which formed the pyroclasts, and hence about the type and intensity of the eruption. The evaluation and analysis of the samples collected at the volcano after each documented eruption will be carried out at the PVL. This physics lab, with a specially-designed experimental setup, allows controlled explosion experiments wherein rock from lava or bombs - related to the sampled pyroclasts - will be melted and subsequently brought to explosion. The energy released during these laboratory experiments will be calibrated to Popocatepetl using the ejecta volume of the observed eruptions, allowing a correlation of the actual energy release to the registered electrical field data. The aims of the project are: (1) quantification of individual magma properties of Popocatepetl (2) on-line measurement of mechanical energy release and mass flux and (3) immediate risk assessment of ongoing volcanic

  7. Another Mexico

    ERIC Educational Resources Information Center

    Romano, Carlin

    2009-01-01

    A Mexican saying holds that "Como Mexico no hay dos"--There is only one Mexico. American media these days interpret that notion with a vengeance. Story after story depicts a country overrun by out-of-control drug wars and murder, where corrupt police officers trip over beheaded victims more often than they nab perpetrators. South of the…

  8. Another Mexico

    ERIC Educational Resources Information Center

    Romano, Carlin

    2009-01-01

    A Mexican saying holds that "Como Mexico no hay dos"--There is only one Mexico. American media these days interpret that notion with a vengeance. Story after story depicts a country overrun by out-of-control drug wars and murder, where corrupt police officers trip over beheaded victims more often than they nab perpetrators. South of the…

  9. [Nesting habitat characterization for Amazona oratrix (Psittaciformes: Psittacidae) in the Central Pacific, Mexico].

    PubMed

    Monterrubio-Rico, Tiberio C; Álvarez-Jara, Margarito; Tellez-Garcia, Loreno; Tena-Morelos, Carlos

    2014-09-01

    The nesting requirements of the Yellow-headed Parrot (Amazona oratrix) are poorly understood, despite their broad historical distribution, high demand for pet trade and current endangered status. Information concerning their nesting requirements is required in order to design specific restoration and conser- vation actions. To assess this, we studied their nesting ecology in the Central Pacific, Michoacan, Mexico during a ten year period. The analyzed variables ranged from local scale nest site characteristics such as nesting tree species, dimensions, geographic positions, diet and nesting forest patches structure, to large scale features such as vegetation use and climatic variables associated to the nesting tree distributions by an ecological niche model using Maxent. We also evaluated the parrot tolerance to land management regimes, and compared the Pacific nest trees with 18 nest trees recorded in an intensively managed private ranch in Tamaulipas, Gulf of Mexico. Parrots nested in tall trees with canopy level cavities in 92 nest-trees recorded from 11 tree species. The 72.8% of nesting occurred in trees of Astronium graveolens, and Enterolobium cyclocarpum which qualified as key- stone trees. The forests where the parrots nested, presented a maximum of 54 tree species, 50% of which were identified as food source; besides, these areas also had a high abundance of trees used as food supply. The lowest number of tree species and trees to forage occurred in an active cattle ranch, whereas the highest species rich- ness was observed in areas with natural recovery. The nesting cavity entrance height from above ground of the Pacific nesting trees resulted higher than those found in the Gulf of Mexico. We hypothesize that the differences may be attributed to Parrot behavioral differences adapting to differential poaching pressure and cavity avail- ability. Nesting trees were found in six vegetation types; however the parrots preferred conserved and riparian semi

  10. Field and Experimental Evidence of Vibrio parahaemolyticus as the Causative Agent of Acute Hepatopancreatic Necrosis Disease of Cultured Shrimp (Litopenaeus vannamei) in Northwestern Mexico

    PubMed Central

    Gomez-Gil, Bruno; Lozano-Olvera, Rodolfo; Betancourt-Lozano, Miguel; Morales-Covarrubias, Maria Soledad

    2014-01-01

    Moribund shrimp affected by acute hepatopancreatic necrosis disease (AHPND) from farms in northwestern Mexico were sampled for bacteriological and histological analysis. Bacterial isolates were molecularly identified as Vibrio parahaemolyticus by the presence of the tlh gene. The tdh-negative, trh-negative, and tlh-positive V. parahaemolyticus strains were further characterized by repetitive extragenic palindromic element-PCR (rep-PCR), and primers AP1, AP2, AP3, and AP and an ems2 IQ2000 detection kit (GeneReach, Taiwan) were used in the diagnostic tests for AHPND. The V. parahaemolyticus strains were used in immersion challenges with shrimp, and farmed and challenged shrimp presented the same clinical and pathological symptoms: lethargy, empty gut, pale and aqueous hepatopancreas, and expanded chromatophores. Using histological analysis and bacterial density count, three stages of AHNPD (initial, acute, and terminal) were identified in the affected shrimp. The pathognomonic lesions indicating severe desquamation of tubular epithelial cells of the hepatopancreas were observed in both challenged and pond-infected shrimp. The results showed that different V. parahaemolyticus strains have different virulences; some of the less virulent strains do not induce 100% mortality, and mortality rates also rise more slowly than they do for the more virulent strains. The virulence of V. parahaemolyticus strains was dose dependent, where the threshold infective density was 104 CFU ml−1; below that density, no mortality was observed. The AP3 primer set had the best sensitivity and specificity. Field and experimental results showed that the V. parahaemolyticus strain that causes AHPND acts as a primary pathogen for shrimp in Mexico compared with the V. parahaemolyticus strains reported to date. PMID:25548045

  11. Noble gases preserve history of retentive continental crust in the Bravo Dome natural CO2 field, New Mexico

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Smye, Andrew J.; Jordan, Jacob S.; Hesse, Marc A.

    2016-06-01

    Budgets of 4He and 40Ar provide constraints on the chemical evolution of the solid Earth and atmosphere. Although continental crust accounts for the majority of 4He and 40Ar degassed from the Earth, degassing mechanisms are subject to scholarly debate. Here we provide a constraint on crustal degassing by comparing the noble gases accumulated in the Bravo Dome natural CO2 reservoir, New Mexico USA, with the radiogenic production in the underlying crust. A detailed geological model of the reservoir is used to provide absolute abundances and geostatistical uncertainty of 4He, 40Ar, 21Ne, 20Ne, 36Ar, and 84Kr. The present-day production rate of crustal radiogenic 4He and 40Ar, henceforth referred to as 4He* and 40Ar*, is estimated using the basement composition, surface and mantle heat flow, and seismic estimates of crustal density. After subtracting mantle and atmospheric contributions, the reservoir contains less than 0.02% of the radiogenic production in the underlying crust. This shows unequivocally that radiogenic noble gases are effectively retained in cratonic continental crust over millennial timescales. This also requires that approximately 1.5 Gt of mantle derived CO2 migrated through the crust without mobilizing the crustally accumulated gases. This observation suggests transport along a localized fracture network. Therefore, the retention of noble gases in stable crystalline continental crust allows shallow accumulations of radiogenic gases to record tectonic history. At Bravo Dome, the crustal 4He*/40Ar* ratio is one fifth of the expected crustal production ratio, recording the preferential release of 4He during the Ancestral Rocky Mountain orogeny, 300 Ma.

  12. Identification of potential B cell epitope determinants by computer techniques, in hemagglutinin-neuraminidase from the porcine rubulavirus La Piedad Michoacan.

    PubMed

    Zenteno-Cuevas, Roberto; Huerta-Yepez, Sara; Reyes-Leyva, Julio; Hernández-Jáuregui, Pablo; González-Bonilla, Cesar; Ramírez-Mendoza, Humberto; Agundis, Concepción; Zenteno, Edgar

    2007-01-01

    Hemagglutinin-neuraminidase (HN) from porcine rubulavirus La Piedad Michoacan (RvpLPM) is one of the most antigenic proteins known, and is responsible for virus-host cell interaction. We analyzed the amino acid sequence of HN, using computer-assisted techniques to identify B cell epitopes. From a pool of 18 possible antigenic peptides, we evaluated the antigenicity of the 2 peptides with the highest scores and the 1 with lowest score. Antibodies from RvpLPM-infected pigs recognized the synthesized HN-A, HN-B, and HN-R peptides (optical density [OD]: 0.33 +/- 0.02 for HN-A, 0.20 +/- 0.02 for HN-B, and 0.07 +/- 0.01 for HN-R); bovine serum albumin-coupled HN-A and HN-B induced rabbit anti-RvpLPM antibodies (OD: 0.39 +/- 0.01 for HN-A and 0.35 +/- 0.02 for HN-B). Loop 5 from the outer membrane protein, OmpC, from Salmonella typhi was replaced with HN-B; this protein was then expressed in Escherichia coli UH302. BALB/c mice were challenged intraperitoneally or orogastrically with the fusion protein expressed in E. coli and murine antibodies obtained from both types of administration inhibited virus-hemagglutinating activity, as did the antibodies from RvpLPM-infected swine. These results suggest that HN-A and HN-B are peptides involved in RvpLPM cell carbohydrate recognition, and could therefore be considered potential targets for vaccine and diagnostic procedures development.

  13. Egade, Mexico.

    ERIC Educational Resources Information Center

    Kubany, Elizabeth

    2001-01-01

    Presents a business school design in Mexico, whose spiral building sits atop a parking structure creating a compact, symbolic form for an arid urban landscape. Includes seven photographs, a floor plan, and sectional drawing. (GR)

  14. Tequila, Mexico

    NASA Image and Video Library

    2011-11-14

    This image from NASA Terra spacecraft shows the city of Tequila, Mexico. Its red volcanic soil surrounding Tequila is particularly well suited to the growing of blue agave, and more than 300 million plants are harvested each year.

  15. Egade, Mexico.

    ERIC Educational Resources Information Center

    Kubany, Elizabeth

    2001-01-01

    Presents a business school design in Mexico, whose spiral building sits atop a parking structure creating a compact, symbolic form for an arid urban landscape. Includes seven photographs, a floor plan, and sectional drawing. (GR)

  16. A Conceptual Model to Link Anomalously High Temperature Gradients in the Cerros del Rio Volcanic Field to Regional Flow in the Espanola Basin, New Mexico

    NASA Astrophysics Data System (ADS)

    Fillingham, E. J.; Keller, S. N.; McCullough, K. R.; Watters, J.; Weitering, B.; Wilce, A. M.; Folsom, M.; Kelley, S.; Pellerin, L.

    2015-12-01

    Temperature-depth well data along with electromagnetic (EM) data were collected by students of the Summer of Applied Geophysics Experience (SAGE) 2015 field season in the Espanola Basin, New Mexico. The data from this year, in addition to data acquired since 2013, were used to construct a conceptual east-west cross-section of the Espanola Basin and the adjacent highlands in order to evaluate the regional flow system. Vertical geothermal gradients from several monitoring wells were measured using a thermistor. Anomalously warm geothermal gradients were mapped in the Cerros del Rio volcanic field in the basin just east of the Rio Grande. Temperature gradients are up to 70℃/km, while the background geothermal gradients in the Rio Grande rift zone generally show 28℃-35℃/km. This anomaly extends to the Buckman well field, which supplies water to the city of Santa Fe. Overpumping of this well field has led to subsidence in the past. However, discharge temperature plots indicate that the temperature gradients of the Buckman field may be rebounding as pumping is reduced. Audiomagnetotelluric (AMT) and transient electromagnetic (TEM) data were acquired in the vicinity of three monitoring wells. TEM and AMT methods complement each other with the former having depths of investigation of less than ten to hundreds of meters and AMT having depths of investigation comparable to the wells deeper than 500m. These datasets were used collectively to image the subsurface stratigraphy and, more specifically, the hydrogeology related to shallow aquifers. The EM data collected at these wells showed a trend indicating a shallow aquifer with a shallower resistive layer of approximately 100 ohm-m at 70-100 meters depth. Beneath this resistive layer we resolved a more conductive, clay-rich layer of 10 ohm-m. These resistivity profiles compliment the electrical logs provided by Jet West, which indicate shallower sandstone interbedded with silt on top of more silt-dominant layers. Our

  17. Sequence stratigraphic setting of turbidite-related petroleum fields, Green Canyon and Ewing Bank lease areas, northern Gulf of Mexico

    SciTech Connect

    Weimer, P.; Pulham, A.J.

    1996-08-01

    The Green Canyon (GC) and Ewing Bank (EW) OCS lease areas have 17 discoveries/fields, primarily from bathyal turbidite systems. Salt has played a significant role in the formation of the intraslope basins that the turbidite systems were deposited in, by influencing the flows of turbidities throughout the basin, in the subsequent trap formation, and, in some cases, as a seal. Nearly every field/discovery is associated with a seismic amplitude anomaly. Fields generally have multiple pay zones, with up to 22 in GC 184 (Jolliet). To date, eight of the fields are producing: EB 826, EB 873 (Lobster), GC 6 (Kodiak), GC 18, GC 53/54 (Marquette), GC 65/110 (Bullwinkle), GC 184 (Jolliet), and GC 205 (Vancouver). Other fields expected to be developed are GC 72/116 (Popeye), GC 254 (Allegheny), GC 200/244 (Olivella), GC and GC 166 (Bison). Other discoveries that were produced and then abandoned include GC 19, and GC29. Producing reservoir facies are highly variable across the area. Turbidite reservoir geometries in Pliocene sands (>1.6 Ma) consist of sheets and amalgamated sheet sands. Pleistocene sands are characterized primarily from channel-levee systems and related deposits. These sands tend to more compartmentalized with separate oil/water or gas/water contacts. Most reservoir sands occur within 100 ft overlying a sequence boundary, indicating the eustatic control on the timing of reservoir sand deposition.

  18. Transboundary pollution: Persistent organochlorine pesticides in migrant birds of the Southwestern United States and Mexico

    USGS Publications Warehouse

    Mora, Miguel A.

    1997-01-01

    The hypothesis that migratory birds accumulate persistent organochlorine pesticides (POPs) during the winter in Latin America has been prevalent for many years, particularly since 1,1,1-trichloro-2,2–bis(p-chlorophenyl)ethane (DDT) was banned in the United States in 1972. It has been suggested that peregrine falcons (Falco peregrinus), black-crowned night herons (Nycticorax nycticorax), white-faced ibises (Plegadis chihi), various migratory waterfowl and shorebirds, and other avian species accumulate higher concentrations of POPs while on migration or on their wintering grounds in Latin America. Nonetheless, the data obtained thus far are limited, and there is no clear pattern to suggest that such accumulation occurs on a widespread basis. In this review wildlife contaminant studies conducted along the U.S.-Mexico border and throughout Mexico are discussed. The results for the most part seem to indicate that no major accumulation of 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene) (DDE), the most persistent organochlorine compound, has occurred or been reported for most parts of Mexico. The majority of the DDE values in birds from Mexico were similar to those reported in birds from the southwestern United States during the same years. More work needs to be done, particularly in those cotton-producing areas of Mexico where DDT was applied heavily in the past (e.g., Chiapas and Michoacan). Because DDT is still used for malaria control and may still be used in agriculture in Chiapas, this state is probably the one where most migrant species would still be at a significant risk of increased accumulation of DDE and DDT.

  19. Integrating field, microstructures, magnetic fabrics, metamorphic studies to establish Yavapai-Mazatazal-aged syntectonic pluton emplacement and strain localization in the Tusas Mountains, New Mexico

    NASA Astrophysics Data System (ADS)

    Davis, P.; Kruckenberg, S. C.

    2012-12-01

    Paleoproterozoic metamorphic rocks in the northern Tusas Mountains of New Mexico record the conditions of deposition, deformation and tectonic processes during assembly and stabilization of these rocks to the southern margin of the Laurentian craton. Metasedimentary and metavolcanic supracrustal rocks of the Vadito and Hondo groups comprise the majority of exposures, detrital zircon from within these units constrain the age of deposition ca. 1.70 Ga. - the Yavapai-Mazatazal temporal orogenic boundary. P-T conditions are ~425-600 C and 4-6 kbars. Two pervasive fold and fabric events are regionally displayed that have been locally modified by a third deformation event. Regional constraints on tectonism timing are mixed, with recent work showing that tectonism occurred ca. 1.4 Ga. Two orthogneiss bodies, the Tres Piedras (TP) and Tusas Mountain (TM) granites, were emplaced into supracrustal host rocks at ca. 1.69 Ga. Several datasets that include mapping and characterization of metamorphic assemblages, EBSD microstructural analysis, and anisotropy of magnetic susceptibility analyses suggest that emplacement was syntectonic. Metamorphic assemblages show a field-gradient that is roughly concentric to the TP and TM plutons from greenschist facies (ca. 400-425 C) in the distant country rock, to upper amphibolite facies (ca. 650 C) near the pluton contacts. This is a new discovery for the region, as most of northern New Mexico displays a regional amphibolite facies signature. Quartz and feldspar microstructures suggest that the body of both plutons record non-coaxial deformation from near solidus to high-T conditions (>600 C). Muscovite inclusions in cm-scale euhedral microcline grains are aligned with S1, and isoclinal folds in the TP lack an axial planar fabric. Measurement of the anisotropy of magnetic susceptibility (AMS) suggest that the orientation of magmatic fabrics within these plutons are consistent with principal regional fabrics (D1) recorded in the

  20. Genetic diversity demonstrated by pulsed field gel electrophoresis of Salmonella enterica isolates obtained from diverse sources in Mexico

    USDA-ARS?s Scientific Manuscript database

    This study was conducted to determine the genetic diversity of Salmonella isolates recovered from a variety of sources using pulsed-field gel electrophoresis (PFGE) to assess their possible relatedness. Salmonella was isolated from ca. 52% of samples from a pepper var. Bell production system. A to...

  1. Quantifying wind blown landscapes using time-series airborne LiDAR at White Sands Dune Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Ewing, R. C.

    2011-12-01

    Wind blown landscapes are a default geomorphic and sedimentary environment in our solar system. Wind sand dunes are ubiquitous features on the surfaces of Earth, Mars and Titan and prevalent within the aeolian rock records of Earth and Mars. Dunes are sensitive to environmental and climatic changes and a complete understanding of this system promises a unique, robust and quantitative record of paleoclimate extending to the early histories of these worlds. However, our understanding of how aeolian dune landscapes evolve and how the details of the wind are recorded in cross-strata is limited by our lack of understanding of three-dimensional dune morphodynamics related to changing boundary conditions such as wind direction and magnitude and sediment source area. We use airborne LiDAR datasets over 40 km2 of White Sands Dune Field collected from June 2007, June 2008, January 2009, September 2009 and June 2010 to quantify 1) three-dimensional dune geometries, 2) annual and seasonal patterns of erosion and deposition across dune topography, 3) spatial changes in sediment flux related to position within the field, 4) spatial changes in sediment flux across sinuous crestlines and 5) morphologic changes through dune-dune interactions. In addition to measurements, we use the LiDAR data along with wind data from two near-by weather stations to develop a simple model that predicts depositional and stratigraphic patterns on dune lee slopes. Several challenges emerged using time series LiDAR data sets at White Sands Dune Field. The topography upon which the dunes sit is variable and rises by 16 meters over the length of the dune field. In order to compare individual dune geometries across the field and between data sets a base surface was interpolated from local minima and subtracted from the dune topography. Co-registration and error calculation between datasets was done manually using permanent vegetated features within the active dune field and structures built by the

  2. Impacts of using an ensemble Kalman filter on air quality simulations along the California-Mexico border region during Cal-Mex 2010 field campaign.

    PubMed

    Bei, Naifang; Li, Guohui; Meng, Zhiyong; Weng, Yonghui; Zavala, Miguel; Molina, L T

    2014-11-15

    The purpose of this study is to investigate the impact of using an ensemble Kalman filter (EnKF) on air quality simulations in the California-Mexico border region on two days (May 30 and June 04, 2010) during Cal-Mex 2010. The uncertainties in ozone (O3) and aerosol simulations in the border area due to the meteorological initial uncertainties were examined through ensemble simulations. The ensemble spread of surface O3 averaged over the coastal region was less than 10ppb. The spreads in the nitrate and ammonium aerosols are substantial on both days, mostly caused by the large uncertainties in the surface temperature and humidity simulations. In general, the forecast initialized with the EnKF analysis (EnKF) improved the simulation of meteorological fields to some degree in the border region compared to the reference forecast initialized with NCEP analysis data (FCST) and the simulation with observation nudging (FDDA), which in turn leading to reasonable air quality simulations. The simulated surface O3 distributions by EnKF were consistently better than FCST and FDDA on both days. EnKF usually produced more reasonable simulations of nitrate and ammonium aerosols compared to the observations, but still have difficulties in improving the simulations of organic and sulfate aerosols. However, discrepancies between the EnKF simulations and the measurements were still considerably large, particularly for sulfate and organic aerosols, indicating that there are still ample rooms for improvement in the present data assimilation and/or the modeling systems.

  3. Scaling laws of the size-distribution of monogenetic volcanoes within the Michoacán-Guanajuato Volcanic Field (Mexico)

    NASA Astrophysics Data System (ADS)

    Pérez-López, R.; Legrand, D.; Garduño-Monroy, V. H.; Rodríguez-Pascua, M. A.; Giner-Robles, J. L.

    2011-04-01

    The Michoacán-Guanajuato Volcanic Field displays about 1040 monogenetic volcanoes mainly composed of basaltic cinder cones. This monogenetic volcanic field is the consequence of a dextral transtensive tectonic regime within the Transmexican Volcanic Belt (TMVB), the largest intra continental volcanic arc around the world, related to the subduction of the Rivera and Cocos plates underneath the North American Plate. We performed a statistical analysis for the size-distribution of the basal diameter (Wco) for cinder cones. Dataset used here was compiled by Hasenaka and Carmichael (1985). Monogenetic volcanoes obey a power-law very similar to the Gutenberg-Richter law for earthquakes, with respect to their size-distribution: log 10 ( N >= Wco ) = α - β log10( Wco), with β = 5.01 and α = 2.98. Therefore, the monogenetic volcanoes exhibit a (Wco) size-distribution empirical power-law, suggesting a self-organized criticality phenomenon.

  4. The anatomy of a cinder cone: preliminary paleomagnetic, rock magnetic, structural, and petrologic data from the La Cienega volcano, Cerros del Rio volcanic field, northern New Mexico

    NASA Astrophysics Data System (ADS)

    Petronis, M. S.; Foucher, M.; Lineline, J.; Van Wyk de Vries, B.

    2011-12-01

    The Cerros del Rio volcanic field is one of several middle Pliocene to Pleistocene basaltic volcanic fields of the axial Rio Grande Rift in central and northern New Mexico. It is a monogenetic volcanic field that comprises about 60 cinder-spatter cones, occupies ~ 700 km2, and ranges in age from 2.7 Ma to 1.1 Ma. Eruptive centers are typically central vent volcanoes, ranging from low-relief shields to steep-sided, breached cinder and spatter cone remnants. They represent short eruptive events that likely were derived from rapidly evolving reservoir-conduit systems. Mining activity has exposed the volcanic plumbing system of the Cienega Mine cinder cone, just west of Santa Fe, NM. Here, geologists from France and USA have been investigating the exposed roots of this eviscerated Pliocene volcano to investigate magma conduit geometry, magma flow structures, and eruption patterns. We are testing models for magma transport and volcano construction using a variety of field and laboratory tools. Common models of volcanic construction envision the magma feeder as a dike or pipe-like conduit transporting molten rock from a deep reservoir to the eruptive vent. We posit that small volcanic pluming systems are inherently more complex and actually involve numerous feeder geometries throughout the volcano lifespan. Our preliminary work suggests that the simple exteriors of some cinder cones hide a long life and complex history, both of which would change the appreciation of the related volcanic hazards in active systems. The Cienega Mine cinder cone consists of several meter- to decimeter-wide intrusions that connect to eruptive centers. These intrusions show a continuity of brittle to ductile structures from their margins to interiors. We have collected samples across each intrusion as well as along strike for anisotropy of magnetic susceptibility (AMS) and petrographic analysis in order to establish magma flow patterns. AMS results yield a remarkably consistent dataset that

  5. Comparative Field Evaluation of Different Traps for Collecting Adult Phlebotomine Sand Flies (Diptera: Psychodidae) in an Endemic Area of Cutaneous Leishmaniasis in Quintana Roo, Mexico.

    PubMed

    Rodríguez-Rojas, Jorge J; Arque-Chunga, Wilfredo; Fernández-Salas, Ildefonso; Rebollar-Téllez, Eduardo A

    2016-06-01

    Phlebotominae are the vectors of Leishmania parasites. It is important to have available surveillance and collection methods for the sand fly vectors. The objectives of the present study were to evaluate and compare traps for the collection of sand fly species and to analyze trap catches along months and transects. Field evaluations over a year were conducted in an endemic area of leishmaniasis in the state of Quintana Roo, Mexico. A randomized-block design was implemented in study area with tropical rainforest vegetation. The study design utilized 4 transects with 11 trap types: 1) Centers for Disease Control and Prevention (CDC) light trap with incandescent bulb (CDC-I), 2) CDC light trap with blue light-emitting diodes (LEDs) (CDC-B), 3) CDC light trap with white LEDs (CDC-W), 4) CDC light trap with red LEDs (CDC-R), 5) CDC light trap with green LEDs (CDC-G), 6) Disney trap, 7) Disney trap with white LEDs, 8) sticky panels, 9) sticky panels with white LEDs, 10) delta-like trap, and 11) delta-like trap with white LEDs. A total of 1,014 specimens of 13 species and 2 genera (Lutzomyia and Brumptomyia) were collected. There were significant differences in the mean number of sand flies caught with the 11 traps; CDC-I was (P  =  0.0000) more effective than the other traps. Other traps exhibited the following results: CDC-W (17.46%), CDC-B (15.68%), CDC-G (14.89%), and CDC-R (14.30%). The relative abundance of different species varied according to trap types used, and the CDC-I trap attracted more specimens of the known vectors of Leishmania spp., such as like Lutzomyia cruciata, Lu. shannoni, and Lu. ovallesi. Disney trap captured more specimens of Lu. olmeca olmeca. Based on abundance and number of species, CDC light traps and Disney traps appeared to be good candidates for use in vector surveillance programs in this endemic area of Mexico.

  6. Modeling the marine magnetic field of Bahía de Banderas, Mexico, confirms the half-graben structure of the bay

    NASA Astrophysics Data System (ADS)

    Alvarez, Román; López-Loera, Héctor; Arzate, Jorge

    2010-06-01

    An existing aeromagnetic survey flown on the central, western portion of Mexico did not include an important tectonic structure: Bahía de Banderas. The bay has an extension of approximately 1400 km 2 and is located within the Puerto Vallarta batholith, a granitic structure of Cretaceous origin. We report here the additional gathering of 5523 magnetic values on the bay, in order to complement the existing land aeromagnetic information; this allowed modeling the structure of the bay from the magnetic viewpoint. A late Miocene age has been proposed for the bay making it roughly contemporaneous with the first stages of separation of Baja California from mainland Mexico. Initially proposed as a graben, it was subsequently shown that its structure actually corresponds to a half-graben of the fault growth type, with reverse drag geometry; it appears to have been developed in response to an extensional process in the ˜ N-S direction. Valle de Banderas neighbors the bay constituting its eastern land continuation; it has also been proposed as a graben and it is also likely the result of an extensional process. However, it seems to be a structure more recently formed, probably around 5 Ma. The different time origin of the bay and of the valley is strengthened by the different alignment of the valley axis, where Ameca River flows and discharges into the bay, of around 30° from the trace of Banderas fault. The magnetic responses of the valley, aeromagnetic and terrestrial, support the existence of an extensional process. Upward and downward continuations of the magnetic fields show that Sierra de Vallejo and Sierra de Zapotán, to the NW of the valley, are deeply rooted structures and their magnetic responses are similar to those obtained in the Puerto Vallarta batholith; these characteristics support a common origin for them. Three magnetic profiles trending NNW are modeled across Bahía de Banderas. The models identify the structure as a half-graben with a listric main

  7. The eruptive history of the Tequila volcanic field, western Mexico: ages, volumes, and relative proportions of lava types

    NASA Astrophysics Data System (ADS)

    Lewis-Kenedi, Catherine B.; Lange, Rebecca A.; Hall, Chris M.; Delgado-Granados, Hugo

    2005-06-01

    The eruptive history of the Tequila volcanic field (1600 km2) in the western Trans-Mexican Volcanic Belt is based on 40Ar/39Ar chronology and volume estimates for eruptive units younger than 1 Ma. Ages are reported for 49 volcanic units, including Volcán Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of volcanic units ≤1 Ma were obtained with the aid of field mapping, ortho aerial photographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km3) and high-Ti basalt (~39 km3) dominated the volcanic field. Between 685 and 225 kyrs ago, less than 3 km3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km3 of andesite erupted to form the stratocone of Volcán Tequila. The phenocryst assemblage of these lavas suggests storage within a chamber at ~2 3 km depth. After a hiatus of ~110 kyrs, ~15 km3 of andesite erupted along the W and SE flanks of Volcán Tequila at ~90 ka, most likely from a second, discrete magma chamber located at ~5 6 km depth. The youngest volcanic feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km3). Over the last 1 Myr, a total of 128±22 km3 of lava erupted in the Tequila volcanic field, leading to an average eruption rate of ~0.13 km3/kyr. This volume erupted over ~1600 km2, leading to an average lava accumulation rate of ~8 cm/kyr. The relative proportions of lava types are ~22 43% basalt, ~0.4 1% basaltic andesite, ~29 54% andesite, ~2 3% dacite, and ~18 40% rhyolite. On the basis of eruptive sequence, proportions of lava types, phenocryst assemblages, textures, and chemical composition, the lavas do not reflect the differentiation of a single (or only a few) parental liquids in a long-lived magma chamber. The rhyolites are geochemically diverse and were likely

  8. 2007 Rocky Mountain Section Friends of the Pleistocene Field Trip - Quaternary Geology of the San Luis Basin of Colorado and New Mexico, September 7-9, 2007

    USGS Publications Warehouse

    Machette, Michael N.; Coates, Mary-Margaret; Johnson, Margo L.

    2007-01-01

    Prologue Welcome to the 2007 Rocky Mountain Cell Friends of the Pleistocene Field Trip, which will concentrate on the Quaternary geology of the San Luis Basin of Colorado and New Mexico. To our best knowledge, Friends of the Pleistocene (FOP) has never run a trip through the San Luis Basin, although former trips in the region reviewed the 'Northern Rio Grande rift' in 1987 and the 'Landscape History and Processes on the Pajarito Plateau' in 1996. After nearly a decade, the FOP has returned to the Rio Grande rift, but to an area that has rarely hosted a trip with a Quaternary focus. The objective of FOP trips is to review - in the field - new and exciting research on Quaternary geoscience, typically research being conducted by graduate students. In our case, the research is more topically oriented around three areas of the San Luis Basin, and it is being conducted by a wide range of Federal, State, academic, and consulting geologists. This year's trip is ambitious?we will spend our first day mainly on the Holocene record around Great Sand Dunes National Park and Preserve, the second day on the Quaternary stratigraphy around the San Luis Hills, including evidence for Lake Alamosa and the 1.0 Ma Mesita volcano, and wrap up the trip's third day in the Costilla Plain and Sunshine Valley reviewing alluvial stratigraphy, the history of the Rio Grande, and evidence for young movement on the Sangre de Cristo fault zone. In the tradition of FOP trips, we will be camping along the field trip route for this meeting. On the night before our trip, we will be at the Great Sand Dunes National Park and Preserve's Pinyon Flats Campground, a group facility located about 2 miles north of the Visitors Center. After the first day's trip, we will dine and camp in the Bachus pit, about 3 miles southwest of Alamosa. For the final night (after day 2), we will bed down at La Junta Campground at the Bureau of Land Management (BLM) Wild and Scenic Rivers State Recreation Area, west of Questa

  9. High-precision 40Ar/39Ar sanidine geochronology of ignimbrites in the Mogollon-Datil volcanic field, southwestern New Mexico

    USGS Publications Warehouse

    McIntosh, W.C.; Sutter, J.F.; Chapin, C.E.; Kedzie, L.L.

    1990-01-01

    40Ar/39Ar age spectra have been obtained from 85 sanidine separates from 36 ignimbrites and one rhyolitic lava in the latest Eocene-Oligocene Mogollon-Datil volcanic field of southwestern New Mexico. Of the 97 measured age spectra, 94 yield weighted-mean plateau ages each giving single-spectrum 1?? precision of??0.25%-0.4% (??0.07-0.14 Ma). Replicate plateau age determinations for eight different samples show within-sample 1?? precisions averaging ??0.25%. Plateau ages from multiple (n=3-8) samples of individual ignimbrites show 1?? within-unit precision of ??0.1%-0.4% (??0.04-0.13 Ma). This within-unit precision represents a several-fold improvement over published K-Ar data for the same ignimbrites, and is similar to the range of precisions reported from single-crystal laser fusion studies. A further indication of the high precision of unit-mean 40Ar/30Ar ages is their close agreement with independently established stratigraphic order. Two samples failed to meet plateau criteria, apparently due to geologic contamination by older feldspars. Effects of minor contamination are shown by six other samples, which yielded slightly anomalous plateau ages. 40Ar/39Ar plateau ages permit resolution of units differing in age by 0.5% (0.15 Ma) or less. This high resolution, combined with paleomagnetic studies, has helped to correlate ignimbrites among isolated ranges and has allowed development of an integrated timestratigraphic framework for the volcanic field. Mogollon-Datil ignimbrites range in age from 36.2 to 24.3 Ma. Ignimbrite activity was strongly episodic, being confined to four brief (<2.6 m.y.) eruptive episodes separated by 1-3 m.y. gaps. Ignimbrite activity generally tended to migrate from the southeast toward the north and west. ?? 1990 Springer-Verlag.

  10. Best Practices for Mudweight Window Generation and Accuracy Assessment between Seismic Based Pore Pressure Prediction Methodologies for a Near-Salt Field in Mississippi Canyon, Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Mannon, Timothy Patrick, Jr.

    Improving well design has and always will be the primary goal in drilling operations in the oil and gas industry. Oil and gas plays are continuing to move into increasingly hostile drilling environments, including near and/or sub-salt proximities. The ability to reduce the risk and uncertainly involved in drilling operations in unconventional geologic settings starts with improving the techniques for mudweight window modeling. To address this issue, an analysis of wellbore stability and well design improvement has been conducted. This study will show a systematic approach to well design by focusing on best practices for mudweight window projection for a field in Mississippi Canyon, Gulf of Mexico. The field includes depleted reservoirs and is in close proximity of salt intrusions. Analysis of offset wells has been conducted in the interest of developing an accurate picture of the subsurface environment by making connections between depth, non-productive time (NPT) events, and mudweights used. Commonly practiced petrophysical methods of pore pressure, fracture pressure, and shear failure gradient prediction have been applied to key offset wells in order to enhance the well design for two proposed wells. For the first time in the literature, the accuracy of the commonly accepted, seismic interval velocity based and the relatively new, seismic frequency based methodologies for pore pressure prediction are qualitatively and quantitatively compared for accuracy. Accuracy standards will be based on the agreement of the seismic outputs to pressure data obtained while drilling and petrophysically based pore pressure outputs for each well. The results will show significantly higher accuracy for the seismic frequency based approach in wells that were in near/sub-salt environments and higher overall accuracy for all of the wells in the study as a whole.

  11. Acoustics lecturing in Mexico

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2002-11-01

    Some thirty years ago acoustics lecturing started in Mexico at the National Polytechnic Institute in Mexico City, as part of the Bachelor of Science degree in Communications and Electronics Engineering curricula, including the widest program on this field in the whole country. This program has been producing acoustics specialists ever since. Nowadays many universities and superior education institutions around the country are teaching students at the B.Sc. level and postgraduate level many topics related to acoustics, such as Architectural Acoustics, Seismology, Mechanical Vibrations, Noise Control, Audio, Audiology, Music, etc. Also many institutions have started research programs in related fields, with participation of medical doctors, psychologists, musicians, engineers, etc. Details will be given on particular topics and development.

  12. Hydrothermal alteration of sediments associated with surface emissions from the Cerro Prieto geothermal field, Baja, California, Mexico

    SciTech Connect

    Valette-Silver, J.N.; Esquer-Patino, I.; Elders, W.A.; Collier, P.C.; Hoagland, J.R.

    1981-01-01

    Surface emissions from the Cerro Prieto geothermal reservoir are restricted to a 100 km/sup 2/ area on the western side of the field, near the volcano Cerro Prieto and the lake Laguna Vulcano. Some 57 surface emissions, explored in 1979, were classified into hot springs, mud pots, pools, fumaroles and geysers (Valette and Esquer-Patino, 1979). A study of the mineralogical changes associated with these hydrothermal vents was initiated with the aim of developing possible exploration tools for geothermal resources. The Cerro Prieto reservoir has already been explored by extensive deep drilling so that relationships between surface manifestations and deeper hydrothermal processes could be established directly. Approximately 120 samples of surface sediments were collected both inside and outside of the vents. The mineralogy of the altered sediments studied appears to be controlled by the type of emission. A comparison between the changes in mineralogy due to low temperature hydrothermal activity in the reservoir, seen in samples from boreholes, and mineralogical changes in the surface emission samples shows similar general trends below 180/sup 0/C: increase of quartz, feldspar and illite, with subsequent disappearance of kaolinite, montmorillonite, calcite and dolomite. These mineral assemblages seem to be characteristics of the discharge from high intensity geothermal fields.

  13. USGS field activity 08FSH01 on the west Florida shelf, Gulf of Mexico, in August 2008

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Liu, Xuewu; Byrne, Robert H.; Raabe, Ellen A.

    2009-01-01

    From August 11 to 15, 2008, a cruise led by the U.S. Geological Survey (USGS) collected air and sea surface partial pressure of carbon dioxide (pCO2), pH, dissolved inorganic carbon (DIC), and total alkalinity (TA) data on the west Florida shelf. Approximately 1,600 data points were collected underway over a 650-kilometer (km) trackline using the Multiparameter Inorganic Carbon Analyzer (MICA). The collection of data extended from Crystal River southward to Marco Island, Florida (~400 km), and westward up to 160 km off the Florida coast. Discrete water samples from approximately 40 locations were also taken at specific localities to corroborate underway data measurements. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 08FSH01 tells us the data were collected in 2008 for the Response of Florida Shelf (FSH) Ecosystems to Climate Change project, and the data were collected during the first field activity for that study in that calendar year.

  14. USGS field activity 09FSH01 on the west Florida shelf, Gulf of Mexico, in February 2009

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Liu, Xuewu; Byrne, Robert H.; Raabe, Ellen A.

    2009-01-01

    From February 24 to 28, 2009, a cruise led by the U.S. Geological Survey (USGS) collected air and sea surface partial pressure of carbon dioxide (pCO2), pH, dissolved inorganic carbon (DIC), and total alkalinity (TA) data on the west Florida shelf. Approximately 1,800 data points were collected underway over a 1,300-kilometer (km) trackline using the Multiparameter Inorganic Carbon Analyzer (MICA). The collection of data extended from Crystal River to Marco Island, Florida (~400 km), and westward up to 160 km off the Florida coast. Discrete water samples were also taken at specific localities to corroborate underway data measurements. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 09FSH01 tells us that the data were collected in 2009 for the Response of Florida Shelf (FSH) Ecosystems to Climate Change project, and the data were collected during the first field activity for that study in that calendar year.

  15. USGS field activity 09FSH02 on the west Florida shelf, Gulf of Mexico, in August 2009

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Liu, Xuewu; Byrne, Robert H.; Raabe, Ellen A.

    2009-01-01

    From August 17 to 21, 2009, a cruise led by the U.S. Geological Survey (USGS) collected air and sea surface partial pressure of carbon dioxide (pCO2), pH, dissolved inorganic carbon (DIC), and total alkalinity (TA) data on the west Florida shelf. Approximately 2,000 data points were collected underway over a 1,320-kilometer (km) track line using the Multiparameter Inorganic Carbon Analyzer (MICA). The collection of data extended from Crystal River to Marco Island, Florida (~400 km), and westward up to 160 km off the Florida coast. Discrete water samples were also taken at specific localities to corroborate underway data measurements. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 09FSH02 tells us that the data were collected in 2009 for the Response of Florida Shelf (FSH) Ecosystems to Climate Change project, and the data were collected during the second field activity for that study in that calendar year.

  16. Mapping the edge of the Cerros del Rio volcanic field, New Mexico: a piece of the puzzle to understanding a potential geothermal resource

    NASA Astrophysics Data System (ADS)

    Pellerin, L.; Gallegos, M.; Goebel, M.; Murphy, B. S.; Smith, J.; Soto, D.; Swiatlowski, J.; Volk, C.; Welch, M.; Feucht, D. W.; Hollingshaus, B.; Bedrosian, P. A.; McPhee, D. K.

    2012-12-01

    The Cerros del Rio volcanic field located west of Santa Fe, New Mexico spans the southwestern part of the Espanola Basin with the Rio Grande to the west. Underlying the volcanics are the Santa Fe Group sediments, which contain the Ancha Formation, an important aquifer in the region. High temperature gradients in water wells reveal a potential geothermal prospect. In 2012 the Summer of Applied Geophysical Experience (SAGE) program acquired transient electromagnetic (TEM), audiomagnetotelluric (AMT), gravity and ground magnetic data to determine the buried eastern margin of the volcanic field and the connectivity related to the underlying sediments. The roughly EW 5-km long transect was sited from USGS aeromagnetic data to cross the boundary of the Cerros del Rio volcanic field. TEM data collected at ten stations, at 200-400 m spacing, along the transect employed an in-loop configuration with a square 100 m x 100 m transmitter loop and both a Zonge receiver coil and a 5 m square receiver loop. The 5 m loop allowed for the recovery of early-time data that was saturated when using the Zonge coil. AMT data were acquired at eight stations, at 400-500 m spacing, using the Geometric Stratagem system recording from 92 kHz to 10 Hz; a horizontal magnetic dipole transmitter was used to augment low signal strength at around 1 kHz. Gravity data along the profile were acquired using CG-3 and CG-5 Scintrex gravimeters with a station interval >250 m. Magnetic data were acquired with a Geometrics Cesium vapor G-858 magnetometer for about 3500 m along the profile at a 0.5 second sampling rate. Two volcanic flows interbedded with Ancha Formation and overlying Santa Fe Group sediments were identified in both the TEM and AMT modeling. High surface resistivity zones (>300 ohm-m) with depths ranging from ~100 to 300 m define the volcanic flows and correspond to high densities (2.3 to 2.55 g/cm3), while low resistivity zones (<30 ohm-m) correspond to lower densities (~2.1 g/cm3). High

  17. Magnetotelluric Investigation of Structures Related to a Geothermal Anomaly in the Buckman Well field in the Rio Grande Rift, New Mexico

    NASA Astrophysics Data System (ADS)

    Jones, D.; Chu, S.; McCormack, K.; Barghouty, L. K.; Mostafanejad, A.; Lasscock, B.; Bedrosian, P.; Pellerin, L.

    2013-12-01

    High borehole temperature gradients have been measured over short spatial scales in the Buckman Well Field located within the Espanola Basin of the Rio Grande Rift, New Mexico. The proximity of the well field to the young Caja del Rio volcanic plateau prompted a study undertaken by the Summer of Applied Geophysical Experience (SAGE) program to uncover structure related to this geothermal anomaly. The localized nature of this geothermal anomaly is suggested to be indicative of a local controlling structure as opposed to a more regional structure. Two-dimensional (2-D) models were constructed using magnetotelluric (MT) and audiomagnetotelluric (AMT) data acquired during 2011-13 seasons of the SAGE field program. Geoelectric strike, being important in determining whether an optimal survey design was employed for 2-D MT inverse modeling, was determined from Swift';s formula, which is subject to galvanic distortion. The geoelectric strike direction obtained from a phase tensor analysis, unaffected by such distortion, generally agreed with the established geological strike of the region. The phase tensor analysis shows predominantly 2-D behavior, although some three-dimensional (3-D) character is observed in the low-frequency MT data. An independent statistical metric developed at SAGE confirms these findings. This observation could be reflected as a conductive anomaly found in the 2-D MT inverse model. Synthetic data were generated to test the sensitivity of the 2-D inversion method to different layer resistivity values and faulted structures in the AMT range. Using these synthetic results to understand the inversion of field data we identify conductive horizons at 100 m and 250-300 m depth. The MT models estimate basin depth at 3-4 km in accordance with independent constraints from geologic mapping, gravity models and seismic imaging. Variations in basement topography correlate to some degree with previously proposed structural features elsewhere beneath the Caja del

  18. Probabilistic Fault Displacement Hazard Assessment For Pipelines, Mad Dog and Atlantis Field Developments, Deepwater Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Angell, M.; Hanson, K.; Swan, F.; Youngs, R.; Abramson, H.

    2004-12-01

    Seafloor faults having strong geomorphic expression and evidence for late Quaternary activity (i.e. < ~150,000 years) are common geologic features associated with the Sigsbee Escarpment. Waterbottom maps derived from exploration 3D multichannel seismic data provided an early indication that several zones of seafloor faults are in the vicinity of the Mad Dog and Atlantis prospect areas. As part of the site investigation activities for field development BP initiated a study to characterize the potential hazard due to fault displacement. The fault displacement hazard study consists of five components: 1) a site-wide structural geologic characterization of the style and origin of active faulting and fault-related deformation; 2) development of a late Quaternary stratigraphic model to evaluate the history, recency, and rate of fault activity at the site; 3) detailed characterization of faulting within limited study areas designated to capture fault behavior in areas of potential facilities development; 4) a general description of the relationship between Quaternary active faulting and slope failure processes within the field area; and 5) a probabilistic fault displacement hazard analysis (PFDHA) of the potential for fault rupture within the designated study areas that relates annual frequency of recurrence of faulting events to the size of the event. Changes in the style and origin of faulting and deformation of shallow (suprasalt) sediment across the individual field areas primarily is due to differences in the depth, geometry, and movement history of the underlying Sigsbee Salt Nappe. These relationships and the resulting geologic model for structural evolution of the suprasalt section has been used effectively to assess the site-wide geohazards not only for faulting, but also indirectly for slope failure and mass-gravity flows. Hazard from potential seafloor offset at fault crossings is judged to be moderate to low. Fault offsets of the shallowest horizons (less than

  19. Permeability enhancement due to cold water injection: A Case Study at the Los Azufres Geothermal Field, Mexico

    SciTech Connect

    Benson, S.M.; Daggett, J.; Ortiz, J.; Iglesias, E.; Comision Federal de Electricidad, Morelia; Instituto de Investigaciones Electricas, Cuernavaca )

    1989-04-01

    Pressure transient buildup and falloff data from 3 wells at the Los Azufres geothermal field have been evaluated to determine the extent to which cold water infection increases the permeability of the near-bore reservoir formation. Simultaneous analysis of the buildup and falloff data provides estimates of the permeability-thickness of the reservoir, the skin factor of the well, and the degree of permeability enhancement in the region behind the thermal front. Estimates of permeability enhancement range from a factor of 4 to 9, for a temperature change of about 150{degree}C. The permeability enhancement is attributed to thermally induced contraction and stress-cracking of the formation. 9 refs., 18 figs.

  20. Sedimentary processes and trace metal contaminants in the buccaneer oil/gas field, northwestern gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Wheeler, Richard B.; Anderson, John B.; Schwarzer, Rudy R.; Hokanson, Claudia L.

    1980-05-01

    Sediments are the ultimate sink for contaminants in the marine environment, and physical processes of sedimentation influence the distribution and accumulation of these contaminants. Evaluation of contaminant levels in sediments is one approach to assessing environmental impact; data interpretation depends on consideration of sediment texture and mineralogy, however, which profoundly influence chemical composition. In this study, comparison of potentially contaminated sediments from the production field with control populations was done only within the context of similar (as to texture and organic carbon and carbonate content) sample groups as determined by cluster analysis. Ba, Cd, and Sr are identified as contaminants. Supported by the identification of a well-crystallized expandable clay—possibly bentonite—drilling fluids are a potential source of Ba. Ba and Sr may be unnaturally high because of their abundance in discharged produced formation waters, but may also be naturally controlled by the unique faunal assemblage associated with the structures. Cd is probably derived from corrosion of the structures and assorted debris on the seafloor. In general, contamination is limited to an area within 100 m of the platforms. Furthermore, substantial erosion around platforms has probably effectively removed and dispersed the bulk of the contaminants introduced into the marine environment by the offshore exploration/production operations.

  1. Mexico City

    Atmospheric Science Data Center

    2013-04-18

    ... sides by mountains and snow-capped volcanoes. Since incident solar radiation does not vary significantly with season at tropical latitudes, ... respectively. Mexico City can be identified in the center panel by the large area of haze accumulation above image center. Two small ...

  2. Mexico's Oxbridge.

    ERIC Educational Resources Information Center

    Haussman, Fay

    1979-01-01

    For 400 years the National Autonomous University of Mexico has remained at the hub of the country's intellectual and political life. The history of the University from the Mayas and the Aztecs, University expansion, upward mobility of students, and student pressure groups and politics are described. (MLW)

  3. Detailed 40Ar/39Ar chronology of the Tancítaro Volcanic Field, Michoacán, Mexico

    NASA Astrophysics Data System (ADS)

    Ownby, S.; Delgado-Granados, H.; Lange, R.; Hall, C. M.

    2005-12-01

    The Tancítaro volcanic field (TVF) is characterized by over 300 cinder cones and fissure fed lava flows, in addition to the ~10 shield volcanoes and 1 large andesite stratovolcano, ~60 km3 Volcán Tancítaro. The TVF is part of the larger Michoacán Guanajuato volcanic field (MGVF) in the Trans Mexican Volcanic Belt, related to subduction of the Cocos plate. We report new 40Ar/39Ar age constraints on the most recent activity from Volcán Tancítaro. Previously, there was only one K-Ar date 530±60 ka for this volcano; Ban et al. (1992). It has been the site of at least two debris avalanche deposits (Capra et al., 2002; Garduno-Monroy, 1999; Ownby et al., 2004), and continues to threaten the cities of Uruapan and Apatzingán in the state of Michoacán, which have a combined population of >300,000. The most recent activity produced a thin blanket of ash (~1-5 m thick along the flanks of the volcano); this ash is tightly bracketed by dates on two nearby shield volcanoes, one underneath (268±14 ka) and the other on top (267±12 ka) of this ash layer. It appears to have triggered a large debris avalanche deposit off the steep slopes of V. Tancítaro (the distinctive ash is mixed in with this avalanche deposit), which itself is bracketed by two cinder cones, one underneath (425±45 ka) and the other on top (179±77 ka). The timing of this ash eruption is close to that for four different andesite lavas from near the summit of V. Tancítaro, which yielded ages of 251±25 ka, 241±25 ka, 228±16 ka, 223±23 ka, respectively. Other dates from the main edifice of V. Tancítaro reveal two earlier episode of activity at ~450 and ~700 ka. We also report an additional set of ~50 40Ar/39Ar ages on various cinder cones, shields, and fissure-fed flows that are peripheral to V. Tancítaro. The samples range in age from ~980 ka to the present, with no obvious breaks in time. They range continuously from 51-62 wt% SiO2, with no breaks in composition. It appears that neither dacite

  4. Paleomagnetic Study of a Miocene Deformation in a Region Close to the Camargo Volcanic Field, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Wogau-Chong, K.; Bohnel, H.; Aranda Gomez, J.

    2009-05-01

    The Sierra the Aguachile is a Miocene volcanic sequence located in the SE of Chihuahua State NW of the Camargo volcanic field and belongs to the Agua Mayo Group, which unconformably overlays Mesozoic calcareous units. The Sierra de Aguachile sequence defines a structure that may be interpreted as a plunging fold, which could be the result of a reactivation of the San Marcos Fault. This major fault is well known more to the east but may extend into the study area where it would be covered by the younger volcanic sequences; its main activity has been reported to be during the the Neocomian with reactivation phases in the Paleogene and Miocene. To test if the observed structure is the result of a tectonic deformation that happened after the emplacement of the volcanic sequence, a paleomagnetic study was carried out. A total of 14 sites were sampled from different parts of the structure, all in the capping ignimbrite layers. Site mean directions were determined using AF demagnetization. The fold test was applied to analyze if the remanence was acquired in situ or before the proposed folding. Precision parameters k before and after application of the tectonic corrections are 25.38 and 31.43, respectively. This indicates that the Sierra de Aguachile indeed was folded after emplacement of the ignimbrites, which restricts the age of the corresponding tectonic event to be younger than 31.3 +/- 0.7 Ma. Due to the gentle folding though, the difference in precision parameters is not significant at the 95% probability level.

  5. Resistance management strategies in malaria vector mosquito control. Baseline data for a large-scale field trial against Anopheles albimanus in Mexico.

    PubMed

    Penilla, R P; Rodríguez, A D; Hemingway, J; Torres, J L; Arredondo-Jiménez, J I; Rodríguez, M H

    1998-07-01

    A high level of DDT resistance and low levels of resistance to organophosphorus, carbamate and pyrethroid insecticides were detected by discriminating dose assays in field populations of Anopheles albimanus in Chiapas, southern Mexico, prior to a large-scale resistance management project described by Hemingway et al. (1997). Biochemical assays showed that the DDT resistance was caused by elevated levels of glutathione S-transferase (GST) activity leading to increased rates of metabolism of DDT to DDE. The numbers of individuals with elevated GST and DDT resistance were well correlated, suggesting that this is the only major DDT resistance mechanism in this population. The carbamate resistance in this population is conferred by an altered acetylcholinesterase (AChE)-based resistance mechanism. The level of resistance observed in the bioassays correlates with the frequency of individuals homozygous for the altered AChE allele. This suggests that the level of resistance conferred by this mechanism in its heterozygous state is below the level of detection by the WHO carbamate discriminating dosage bioassay. The low levels of organophosphate (OP) and pyrethroid resistance could be conferred by either the elevated esterase or monooxygenase enzymes. The esterases were elevated only with the substrate pNPA, and are unlikely to be causing broad spectrum OP resistance. The altered AChE mechanism may also be contributing to the OP but not the pyrethroid resistance. Significant differences in resistance gene frequencies were obtained from the F1 mosquitoes resulting from adults obtained by different collection methods. This may be caused by different insecticide selection pressures on the insects immediately prior to collection, or may be an indication that the indoor- and outdoor-resting A. albimanus collections are not from a randomly mating single population. The underlying genetic variability of the populations is currently being investigated by molecular methods.

  6. Evolution of silicic magma in the upper crust: the mid-Tertiary Latir volcanic field and its cogenetic granitic batholith, northern New Mexico, USA

    USGS Publications Warehouse

    Lipman, P.W.

    1988-01-01

    Structural and topographic relief along the eastern margin of the Rio Grande rift, northern New Mexico, provides a remarkable cross-section through the 26-Ma Questa caldera and cogenetic volcanic and plutonic rocks of the Latir field. Exposed levels increase in depth from mid-Tertiary depositional surfaces in northern parts of the igneous complex to plutonic rocks originally at 3-5 km depths in the S. Erosional remnants of an ash-flow sheet of weakly peralkaline rhyolite (Amalia Tuff) and andesitic to dactitic precursor lavas, disrupted by rift-related faults, are preserved as far as 45 km beyond their sources at the Questa caldera. Broadly comagmatic 26 Ma batholithic granitic rocks, exposed over an area of 20 by 35 km, range from mesozonal granodiorite to epizonal porphyritic granite and aplite; shallower and more silicic phases are mostly within the caldera. Compositionally and texturally distinct granites defined resurgent intrusions within the caldera and discontinuous ring dikes along its margins: a batholithic mass of granodiorite extends 20 km S of the caldera and locally grades vertically to granite below its flat-lying roof. A negative Bouguer gravity anomaly (15-20 mgal), which encloses exposed granitic rocks and coincides with boundaries of the Questa caldera, defined boundaries of the shallow batholith, emplaced low in the volcanic sequence and in underlying Precambrian rocks. Paleomagnetic pole positions indicate that successively crystallised granitic plutons cooled through Curie temperatures during the time of caldera formation, initial regional extension, and rotational tilting of the volcanic rocks. Isotopic ages for most intrusions are indistinguishable from the volcanic rocks. These relations indicate that the batholithic complex broadly represents the source magma for the volcanic rocks, into which the Questa caldera collapsed, and that the magma was largely liquid during regional tectonic disruption. -from Author

  7. Cerro Toledo Rhyolite, Jemez Volcanic Field, New Mexico: {sup 40}Ar/{sup 39}Ar geochronology of eruptions between two caldera-forming events

    SciTech Connect

    Spell, T.L. |; McDougall, I.; Doulgeris, A.P.

    1996-12-01

    The Cerro Toledo Rhyolite comprises a group of domes and tephra which were erupted during the interval between two caldera-forming ignimbrites, the Tshirege Member and Otowi Member of the Bandelier Tuff, in the Jemez Volcanic Field, New Mexico. To provide a chronologic framework for geochemical and isotopic studies on these rhyolites, which record the evolution of the Bandelier magma system during this interval, a {sup 40}Ar/{sup 39}Ar geochronology study was undertaken. Pumice from major pyroclastic fall deposits within the rhyolite tephra and samples from the rhyolite domes were dated as well as the stratigraphically bracketing Bandelier Tuff. The {sup 40}Ar/{sup 39}Ar ages for the two members of the Bandelier Tuff Yield and interval of 380{+-}20 k.y. between these caldera forming eruptions. During this interval nine major pyroclastic pumice units were deposited in the sections studies, for which six yield isochron ages, one a weighted mean age, one a maximum age, and one no reliable age due to lack of sanidine. {sup 40}Ar/{sup 39}Ar dates on pumice fall units within the Cerro Toledo Rhyolite tephra indicate that eruptive activity occurred at > 1.59, 1.54, 1.48, 1.37 and 1.22 Ma. {sup 40}Ar/{sup 39}Ar dating of Cerro Toledo Rhyolite domes indicates these were erupted within the caldera at 1.54, 1.45, 1.38-1.34, and 1.27 Ma. The dates obtained indicate that eruptive activity occurred throughout the 380 k.y. interval between the two members of the Bandelier Tuff, but suggest that eruptions producing both tephra and domes occurred during discrete intervals at ca. 1.54, 1.48 and 1.38-1.34 Ma. 43 refs., 5 figs., 3 tabs.

  8. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    SciTech Connect

    Birkle, P.; Pruess, K.; Xu, T.; Figueroa, R.A. Hernandez; Lopez, M. Diaz; Lopez, E. Contreras

    2008-10-01

    Waterflooding for enhanced oil recovery requires that injected waters must be chemically compatible with connate reservoir waters, in order to avoid mineral dissolution-and-precipitation cycles that could seriously degrade formation permeability and injectivity. Formation plugging is a concern especially in reservoirs with a large content of carbonates, such as calcite and dolomite, as such minerals typically react rapidly with an aqueous phase, and have strongly temperature-dependent solubility. Clay swelling can also pose problems. During a preliminary waterflooding pilot project, the Poza Rica-Altamira oil field, bordering the Gulf coast in the eastern part of Mexico, experienced injectivity loss after five months of reinjection of formation waters into well AF-847 in 1999. Acidizing with HCl restored injectivity. We report on laboratory experiments and reactive chemistry modeling studies that were undertaken in preparation for long-term waterflooding at Agua Frma. Using analogous core plugs obtained from the same reservoir interval, laboratory coreflood experiments were conducted to examine sensitivity of mineral dissolution and precipitation effects to water composition. Native reservoir water, chemically altered waters, and distilled water were used, and temporal changes in core permeability, mineral abundances and aqueous concentrations of solutes were monitored. The experiments were simulated with the multi-phase, nonisothermal reactive transport code TOUGHREACT, and reasonable to good agreement was obtained for changes in solute concentrations. Clay swelling caused an additional impact on permeability behavior during coreflood experiments, whereas the modeled permeability depends exclusively on chemical processes. TOUGHREACT was then used for reservoir-scale simulation of injecting ambient-temperature water (30 C, 86 F) into a reservoir with initial temperature of 80 C (176 F). Untreated native reservoir water was found to cause serious porosity and

  9. A History of Distance Education in Mexico

    ERIC Educational Resources Information Center

    Castaneda, Manuel Moreno

    2005-01-01

    Research on distance education in Mexico is still in the embryonic stage, in spite of its long history. One indication is that among the lines of research defined by the Mexican Council on Educational Research, the leading organization in the field in Mexico, distance education does not even appear. Only recently, in the last few years, has an…

  10. A History of Distance Education in Mexico

    ERIC Educational Resources Information Center

    Castaneda, Manuel Moreno

    2005-01-01

    Research on distance education in Mexico is still in the embryonic stage, in spite of its long history. One indication is that among the lines of research defined by the Mexican Council on Educational Research, the leading organization in the field in Mexico, distance education does not even appear. Only recently, in the last few years, has an…

  11. Origin of metaluminous and alkaline volcanic rocks of the Latir volcanic field, northern Rio Grande rift, New Mexico

    USGS Publications Warehouse

    Johnson, C.M.; Lipman, P.W.

    1988-01-01

    Volcanic rocks of the Latir volcanic field evolved in an open system by crystal fractionation, magma mixing, and crustal assimilation. Early high-SiO2 rhyolites (28.5 Ma) fractionated from intermediate compositionmagmas that did not reach the surface. Most precaldera lavas have intermediate-compositions, from olivine basaltic-andesite (53% SiO2) to quartz latite (67% SiO2). The precaldera intermediate-composition lavas have anomalously high Ni and MgO contents and reversely zoned hornblende and augite phenocrysts, indicating mixing between primitive basalts and fractionated magmas. Isotopic data indicate that all of the intermediate-composition rocks studied contain large crustal components, although xenocrysts are found only in one unit. Inception of alkaline magmatism (alkalic dacite to high-SiO2 peralkaline rhyolite) correlates with, initiation of regional extension approximately 26 Ma ago. The Questa caldera formed 26.5 Ma ago upon eruption of the >500 km3 high-SiO2 peralkaline Amalia Tuff. Phenocryst compositions preserved in the cogenetic peralkaline granite suggest that the Amalia Tuff magma initially formed from a trace element-enriched, high-alkali metaluminous magma; isotopic data suggest that the parental magmas contain a large crustal component. Degassing of water- and halogen-rich alkali basalts may have provided sufficient volatile transport of alkalis and other elements into the overlying silicic magma chamber to drive the Amalia Tuff magma to peralkaline compositions. Trace element variations within the Amalia Tuff itself may be explained solely by 75% crystal fractionation of the observed phenocrysts. Crystal settling, however, is inconsistent with mineralogical variations in the tuff, and crystallization is thought to have occurred at a level below that tapped by the eruption. Spatially associated Miocene (15-11 Ma) lavas did not assimilate large amounts of crust or mix with primitive basaltic magmas. Both mixing and crustal assimilation processes

  12. Magnetic Properties in Volcanoclastic Deposits in the Valle de Santiago, Guanajuato, in Central Mexico.

    NASA Astrophysics Data System (ADS)

    Uribe-Cifuentes, R.; Fucugauchi, J. U.

    2005-05-01

    Valle de Santiago is a volcanic province, part of the Michoacan-Guanajuato volcanic field. The area is characterized by volcanic maars. These structures show a very well defined NW-SE direction. In this study, three sequences are described and analysed in order to determinate their magnetic properties, specially, anisotropy of magnetic susceptibility (AMS), and determinate different types of signatures in relation to nature of deposits. The sequences of maars contain a high percentage of reworked material (approximately 65-75) from previous rocks. This arrangement is directly related with a high kinetic energy during the eruption. All the deposits are unwelded, and principally are fine grained pyroclastic deposits of hydromagmatic origin. Volcanic and magnetic data suggest an alternation of fall and turbulent transportation and traction deposition of particles. The preliminary results indicate the anisotropy of magnetic susceptibility (AMS) could be related with grain size, chemical composition, and type of deposit.

  13. Diverse mantle and crustal components in lavas of the NW Cerros del Rio volcanic field, Rio Grande Rift, New Mexico

    NASA Astrophysics Data System (ADS)

    Duncker, K. E.; Wolff, J. A.; Harmon, R. S.; Leat, P. T.; Dickin, A. P.; Thompson, R. N.

    1991-09-01

    Products of Pliocene (2 4 Ma) mafic to intermediate volcanism in the northwestern Cerros del Rio, a dominantly mafic volcanic field in the Española Basin of the Rio Grande Rift (RGR), range from 49% to 63% SiO2 and exhibit diversity in silica saturation, trace-element patterns, and isotopic compositions. Tholeiites, which are largely confined to west of the Rio Grande, have trace-element abundances that resemble those of oceanic basalts, but with mild depletions in Nb and Ta, and high 87Sr/86Sr, low 143Nd/144Nd, and high δ18O compared to typical OIB. They are regarded as asthenospherically-derived magmas contaminated with continental crust. Alkali basalts and hawaiites erupted from vents east of the Rio Grande are geochemically distinct, having generally higher overall incompatible-element abundances, but with pronounced depletions in K, Rb, Nb and Ta with respect to Th and LREE. Spatially-associated benmoreites, mugearites and latites (collectively termed “evolved” lavas) have similar trace-element characteristics to the mafic mildly-alkaline compositions, but are typically not as depleted in K. Hawaiites and evolved lavas exhibit a good negative correlation of 143Nd/144Nd with SiO2, due to interaction with lower continental crust. The most silicic “evolved” lavas carry the highest proportions of crustal material, and consequently have higher K/Th than the related hawaiites. Several (mostly mafic) lavas contain abundant crustally-derived resorbed quartz xenocrysts in O-isotope disequilibrium with the host magma. The δ18O values of xenocrystic quartz range over 4‰, indicating a variety of quartz-bearing crustal contaminants beneath the Española Basin. The hawaiites, with their unusual combination of trace-element enrichments and depletions, cannot be generated by any process of fractionation or crustal contamination superposed on a common mantle source type (oceanic or arc-source). It is a regional mantle source type, inasmuch as it was also present

  14. ALARA development in Mexico

    SciTech Connect

    Lopez, M.A.M.

    1995-03-01

    Even though the ALARA philosophy was formally implemented in the early 1980`s, to some extent, ALARA considerations already had been incorporated into the design of most commercial equipment and facilities based on experience and engineering development. In Mexico, the design of medical and industrial facilities were based on international recommendations containing those considerations. With the construction of Laguna Verde Nuclear Power Station, formal ALARA groups were created to review some parts of its design, and to prepare the ALARA Program and related procedures necessary for its commercial operation. This paper begins with a brief historical description of ALARA development in Mexico, and then goes on to discuss our regulatory frame in Radiation Protection, some aspects of the ALARA Program, efforts in controlling and reducing of sources of radiation, and finally, future perspectives in the ALARA field.

  15. Mechanized and natural soil-to-air transfer of trifluralin and prometryn from a cotton field in Las Cruces, New Mexico.

    PubMed

    Holmén, Britt A; Kasumba, John; Hiscox, April; Wang, Junming; Miller, David

    2013-10-16

    Two pre-emergence herbicides (trifluralin and prometryn) were applied on a cotton field in Las Cruces, New Mexico, and their atmospheric particle and gas-phase concentrations were measured during mechanized soil preparation and natural wind erosion sampling events before and after herbicide application. Air sampling was conducted using samplers mounted at various heights from the ground and at various locations on the field. During mechanized soil management with a disk harrow, sampling occurred at two distances from the tractor ("near-source", 4 m downwind and "far-source", 20-100 m from the disking tractor). Natural background (no disking) sampling events occurred during daytime and at night. Both herbicides were quantifiable for all postapplication sampling events, including background sampling that occurred 8, 38, and 40 days after herbicide application. Average concentrations in both the gas and particle phases ranged from about 10 to 350 ng/m(3). Averaging by event type, mean total prometryn concentrations were 2 (night background) to 8 (near-source) times higher than the corresponding trifluralin concentrations. Prometryn/trifluralin ratios were higher in airborne samples than in soil, indicative of trifluralin losses during daytime sampling, possibly via atmospheric reactions. Prometryn particle phase mass fractions were generally higher than those for trifluralin for all sampling events, consistent with Kair/soil-oc partition coefficients, and particle-phase mass fractions were higher for near-source disking and daytime background sampling compared to far-source and nighttime. Daytime natural background prometryn concentrations could be as high as those measured during disking, and background samples showed significant relationships to meteorological parameters (air temperature, relative humidity, and dewpoint). Mechanical disturbance by tilling operations reduced the ability to predict airborne herbicide concentrations on the basis of meteorological

  16. Aflatoxin-producing fungi in maize field soils from sea level to over 2000 masl: a three year study in Sonora, Mexico.

    PubMed

    Ortega-Beltran, Alejandro; Jaime, Ramon; Cotty, Peter J

    2015-04-01

    Aflatoxins, highly toxic carcinogens produced by several members of Aspergillus section Flavi, contaminate crops in temperate zones. In the state of Sonora, Mexico, maize is cultivated from 0 to 2100 masl with diverse cultivation practices. This is typical of the nation. In order to design better sampling strategies across Mexico, aflatoxin-producing fungal communities associated with maize production during 2006, 2007, and 2008 in Sonora were investigated in four agro-ecological zones (AEZ) at varying elevation. Fungal communities were dominated by the Aspergillus flavus L strain morphotype (46%), but variation occurred between years and among AEZ. Several atoxigenic isolates with potential to be used as biocontrol agents for aflatoxin mitigation were detected in all AEZ. The characteristics of each AEZ had minimal influences on fungal community structure and should not be a major consideration for future sampling designs for Mexico. Insights into the dynamics and stability of aflatoxin-producing fungal communities across AEZ are discussed. Published by Elsevier Ltd.

  17. Evaluation of solitary waves as a mechanism for oil transport in poroelastic media: A case study of the South Eugene Island field, Gulf of Mexico basin

    SciTech Connect

    Joshi, Ajit; Appold, Martin S.; Nunn, Jeffrey A.

    2012-11-01

    Hydrocarbons in shallow reservoirs of the Eugene Island 330 field in the Gulf of Mexico basin are thought to have migrated rapidly along low permeability sediments of the Red fault zone as discrete pressure pulses from source rocks at depths of about 4.5 km. The aim of this research was to evaluate the hypothesis that these pressure pulses represent solitary waves by investigating the mechanics of solitary wave formation and motion and wave oil transport capability. A two-dimensional numerical model of Eugene Island minibasin formation predicted overpressures at the hydrocarbon source depth to increase at an average rate of 30 Pa/yr, reaching 52 MPa by the present day and oil velocities of 1E-12 m/yr, far too low for kilometer scale oil transport to fill shallow Plio-Pleistocene reservoirs within the 3.6 million year minibasin history. Calculations from a separate one-dimensional model that used the pressure generation rate from the two-dimensional model showed that solitary waves could only form and migrate within sediments that have very low permeabilities between 1-25 to 1-24 m2 and that are highly overpressured to 91-93% of lithostatic pressure. Solitary waves were found to have a maximum pore volume of 105 m3, to travel a maximum distance of 1-2 km, and to have a maximum velocity of 1-3 m/yr. Based on these results, solitary waves are unlikely to have transported oil to the shallowest reservoirs in the Eugene Island field in a poroelastic fault gouge rheology at the pressure generation rates likely to have been caused by disequilibrium compaction and hydrocarbon generation. However, solitary waves could perhaps be important agents for oil transport in other locations where reservoirs are closer to the source rocks, where the pore space is occupied by more than one fluid, or where sudden fracturing of overpressured hydrocarbon source sediments would allow the solitary waves to propagate as shock waves. Hydrocarbons in shallow reservoirs of the Eugene Island 330

  18. Flux Emissions of SO2 and NO2 Measured at the Tula Industrial Complex (Mexico) during MCMA 2006 Field Campaign using a Mini-DOAS System

    NASA Astrophysics Data System (ADS)

    Sosa, G.; Rivera, C.; Wöhrnschimmel, H.; de Foy, B.; Johansson, M.; Molina, L. T.

    2007-05-01

    The Tula industrial zone is located 60 km northeast from the Mexico City Metropolitan Area (MCMA), in the Hidalgo State in México. This region is known as the Tula-Vito-Apasco industrial corridor, where a number of industries are located. According to the latest information from the environmental authority, about 313,000 ton/year of SO2 and 40,000 ton/year of NOx are released in this region. The Miguel Hidalgo refinery (MHR) and the Francisco Pérez Ríos power plant (FPRPP) are the main emitters, contributing almost 90% of SO2 and 80% of NOx from the total emission inside the Hidalgo State. Other industries such as cement plants, open-sky mines and agricultural activities are also responsible for important emissions of particulat matter (PM) into the atmosphere and soil erosion. This highly industrialized region is thought to influence the air quality in the MCMA, where in some occasions SO2 concentrations in the north part of the city have exceeded the Mexican air quality standard (130 ppb as a 24 hour average), which could not be attributed to irregular operations of industries located in the surrounding area. To address the question of emissions from the refinery and the power plant, the total fluxes of SO2 and NO2 were determined by measurements of their respective integrated vertical column in the neighborhood of the Tula industrial zone, using a Mini-DOAS system. These measurements were carried out as part of the MCMA-2006/MILAGRO Field Campaign, from March 24th to April 18th 2006. Meteorological measurements at the height of the plume dispersion were also determined using pilot balloons and radiosondes techniques. The experimental data were complemented by model simulations. Forward Lagrangian stochastic trajectories were calculated to simulate the plume using FLEXPART in combination with meso-scale meteorological simulations with MM5. The experimental data set was used to evaluate model performance. The simulations were used as an additional estimate of

  19. Land Subsidence and Groundwater Resources Investigations with the Use of D-InSAR, Numerical Modeling, and Field Data in the Toluca Valley, Mexico

    NASA Astrophysics Data System (ADS)

    Calderhead, A. I.; Martel, R.; Rivera, A.; Garfias, J.; Therrien, R.

    2008-12-01

    In the Toluca Valley, Mexico, urban and industrial growth have resulted in groundwater pumping exceeding recharge. Currently, there is a significant water budget deficit within the basin primarily due to groundwater pumping, and the loss is increasing with time. The stresses on the aquifer have caused significant changes on the water flow patterns, a reversal in the direction of hydraulic gradients, the disappearance of artesian springs and wetlands and noticeable land subsidence within the basin. The focus of this study is the investigation of water resources and land subsidence with the use of Differential Synthetic Aperture Radar Interferometry (D-InSAR), numerical modeling, and field data. The study is divided into two parts: 1) investigation of groundwater depletion in the Toluca Valley; and 2) assessment of land subsidence in the Toluca Valley. A spatially variable recharge model based on the Hydrologic Evaluation of Landfill Performance (HELP) numerical model examines the recharge; pumping estimates are based on a recent census and differences in piezometric surfaces. Currently there is a net loss (recharge - pumping) of over 150 million cubic meters per year of groundwater within the Toluca Basin aquifers. We examine various changes in regional flow patterns, and groundwater levels decline throughout the valley. At the current rate of consumption, groundwater resources are not sustainable for the population of the valley. Directly related to the decrease in groundwater levels is the occurrence of land subsidence. Regional land subsidence of the Toluca Valley is observed with the use of SAR images obtained from the European Space agency's ERS-1, ERS-2 and ENVISAT Satellites and the Canadian Space Agency's RADARSAT-1 satellite. Data from years 1996 to 2008 are used to locate and quantify the subsidence; with subsidence rates reaching more than 15 cm/year. Results from the different sensors are also compared. The findings are verified with in

  20. Evaluation of the solute geothermometry of thermal springs and drilled wells of La Primavera (Cerritos Colorados) geothermal field, Mexico: A geochemometrics approach

    NASA Astrophysics Data System (ADS)

    Pandarinath, Kailasa; Domínguez-Domínguez, Humberto

    2015-10-01

    A detailed study on the solute geothermometry of thermal water (18 springs and 8 drilled wells) of La Primavera geothermal field (LPGF) in Mexico has been carried out by employing a geochemical database compiled from the literature and by applying all the available solute geothermometers. The performance of these geothermometers in predicting the reservoir temperatures has been evaluated by applying a geochemometrics (geochemical and statistical) method. The springs of the LPGF are of bicarbonate type and the majority have attained partial-equilibrium chemical conditions and the remaining have shown non-equilibrium conditions. In the case of geothermal wells, water is dominantly of chloride-type and, among the studied eight geothermal wells, four have shown full-equilibrium chemical conditions and another four have indicated partial-equilibrium conditions. All springs of HCO3-​ type water have provided unreliable reservoir temperatures, whereas the only one available spring of SO42- type water has provided the reservoir temperature nearer to the average BHT of the wells. Contrary to the general expected behavior, spring water of non-equilibrium and geothermal well water of partial-equilibrium chemical conditions have indicated more reliable reservoir temperatures than those of partially-equilibrated and fully-equilibrated water, respectively. Among the chemical concentration data, Li and SiO2 of two springs, SO42- and Mg of four springs, and HCO3 and Na concentrations of two geothermal wells were identified as outliers and this has been reflected in very low reservoir temperatures predicted by the geothermometers associated with them (Li-Mg, Na-Li, Na-K-Mg, SiO2 etc.). Identification of the outlier data points may be useful in differentiating the chemical characteristics, lithology and the physico-chemical and geological processes at the sample locations of the study area. In general, the solute geothermometry of the spring waters of LPGF indicated a dominantly

  1. Aflatoxin-producing fungi in maize field soils from sea level to over 2000 masl: A three year study in Sonora, Mexico

    USDA-ARS?s Scientific Manuscript database

    Aflatoxins, highly toxic carcinogens produced by several members of Aspergillus section Flavi, contaminate crops in temperate zones. Maize is cultivated from 0 to 2,100 masl under diverse growing regimes in the state of Sonora, Mexico. This is typical of the nation. In order to design sampling strat...

  2. PREFACE: XIV Mexican School on Particles and Fields

    NASA Astrophysics Data System (ADS)

    Bashir, Adnan; Contreras, Guillermo; Raya, Alfredo; Tejeda-Yeomans, Maria Elena

    2011-03-01

    The XIV Mexican School on Particles and Fields took place from 8-12 November, 2010, in the colonial city of Morelia, Michoacan, Mexico. The format of the school was such that the morning sessions were devoted to theoretical and experimental reviews, whereas parallel thematic sessions were held in the afternoons. All the reviews and seminars were delivered by experts of international prestige on subjects which are of current interest to the global scientific community and are also actively pursued within Mexico. In order to equip the attending graduate students and post docs with the necessary introductory tools to allow them to benefit substantially from the specialized seminars, a series of mini-courses were offered prior to the event from 4-7 November 2010, in the Auditorium of the Faculty of Science of the University of Michoacan (UMSNH). The length of each course was about 5 hours, English being the language of instruction. An informal and friendly atmosphere was encouraged during the courses so that the students could overcome their inhibitions and actively participate in the discussions. A novel feature of this event was a colloquium aimed at the general public and younger students of pre-undergraduate level, which allowed the expert scientists to reach out to a wider community and raise their awareness and interest in one of the most fascinating and vital fields of knowledge. The XIV-MSPF was organized by the Division of Particles and Fields of the Mexican Physical Society. It was generously sponsored by several institutions: Consejo Estatal de Ciencia y Tecnológico (COECyT) del Estado de Michoacán, Universidad Michoacana de San Nicolás de Hidalgo, Universidad de Sonora, Universidad Nacional Autónoma de México, Universidad de Guanajuato, Universidad de Sinaloa, Centro de Investigaciones de Estudios Avanzados del IPN (CINVESTAV), Consejo Nacional de Ciencia y Tecnología (CONACyT), la Academia Mexicana de Ciencias and, most importantly, the Red Nacional

  3. Long-Term Continuous Monitoring of Fluid Chemistry and Flux at the Bush Hill Gas Hydrate Field, Gulf of Mexico Using a New Flow Meter, The MOSQUITO

    NASA Astrophysics Data System (ADS)

    Solomon, E.; Kastner, M.; Jannasch, H.; Weinstein, Y.; Robertson, G.; Aubrey, A.

    2004-12-01

    Long-term monitoring of fluid, solute, and methane fluxes that influence marine gas hydrate formation and dissociation has important implications for the seafloor biochemical environment, ocean chemistry, and potentially the atmosphere. Four newly designed flux meters called the MOSQUITO (Multiple Orifice Sampler and Quantitative Injection Tracer Observer) and two temperature loggers were deployed adjacent to the Bush Hill hydrate mound in the northern Gulf of Mexico (GC185) in order to understand how chemistry, physics, biology, and subsurface hydrology dynamically influence the growth and dissociation of the hydrate mound. The MOSQUITO contains a network of osmotic samplers and a tracer injection device, each connected to a titanium capillary tube that penetrates the sediment. The tracer is injected as a point source, and fluid chemistry and tracer concentrations are continuously sampled simultaneously at multiple depths below the seafloor in a three dimensional array with respect to the tracer injection point. Bottom water chemistry is also sampled continuously. Vertical and horizontal flow rates as low as 1 cm/yr are determined by modeling the variability in tracer concentration at each depth over time. MOSQUITOs can be deployed at passive margins, ridge crests, ridge flanks, subduction zones, and lakes. MOSQUITOs were deployed over a period of 430 days from June 2002 to August 2003 and were sampled at weekly resolution. The temperature loggers were attached to the MOSQUITOs and recorded seafloor temperature every 40 minutes. Three MOSQUITOs were deployed within 3 m of the hydrate mound and ˜ 5 m apart, adjacent to transient methane seeps; in a mussel field, in a bacterial mat, and in a tubeworm field. The fourth MOSQUITO was placed ˜150 m southwest of the hydrate mound to monitor background fluid flow, geochemistry, and temperature. The average bottom water temperature over the 430-day deployment period was 7.94° C, with minimum temperatures occurring every

  4. The petrologic history of the Sanganguey volcanic field, Nayarit, Mexico: Comparisons in a suite of crystal-rich and crystal-poor lavas

    NASA Astrophysics Data System (ADS)

    Crabtree, Stephen M.; Waters, Laura E.

    2017-04-01

    To evaluate if intermediate magmas erupting from Volcán Sanganguey (Mexico) and the surrounding volcanic field are formed by mixing of basalts and rhyolites or if they initially exist as intermediate liquids, a detailed petrological study is presented for eight andesite and dacite magmas. Six of the samples erupted from the central edifice (four andesites and two dacites) are crystal-rich (≤ 50 vol%), whereas the remaining two samples (one andesite and one dacite) erupted from monogenetic vents in the peripheral volcanic field and are crystal poor (≤ 5 vol%). Despite the variation in crystallinity, all samples are multiply saturated in five to seven mineral phases (plagioclase + orthopyroxene + titanomagnetite + ilmenite + apatite ± clinopyroxene ± hornblende). In all samples, plagioclase spans a 30-40 mol% An range in composition and orthopyroxene spans a range in Mg# of 5-10. Pre-eruptive temperatures and oxygen fugacites (relative to the NNO buffer) range from 853 (± 24) to 1085 (± 16) °C and - 0.1 (± 0.1) to 0.9 (± 0.1) ∆ NNO, on the basis of Fe-Ti two oxide thermometry. Application of the plagioclase-liquid hygrometer to the samples reveals maximum H2O contents that range from 1.7-6.2 wt%. Comparison with phase equilibrium experiments demonstrates that all plagioclase and orthopyroxene compositions in the crystal-poor samples could have grown from their respective whole rock compositions. Comparison of crystal rich samples with phase equilibrium experiments reveals the presence of sodic xenocrysts which reflect resorption textures and an estimated excess plagioclase crystal cargo of > 6 vol%. The excess plagioclase crystal cargo is not distinguishable from phenocrystic plagioclase based on composition or texture, suggesting that they were also grown in intermediate melts, and are therefore described as antecrystic. No calcic plagioclase xenocrysts (> An79) typical of hydrous arc basalts are observed, thus it is likely that the excess plagioclase

  5. Potential field studies of the central San Luis Basin and San Juan Mountains, Colorado and New Mexico, and southern and western Afghanistan

    NASA Astrophysics Data System (ADS)

    Drenth, Benjamin John

    This dissertation includes three separate chapters, each demonstrating the interpretive utility of potential field (gravity and magnetic) geophysical datasets at various scales and in various geologic environments. The locations of these studies are the central San Luis Basin of Colorado and New Mexico, the San Juan Mountains of southwestern Colorado, and southern and western Afghanistan. The San Luis Basin is the northernmost of the major basins that make up the Rio Grande rift, and interpretation of gravity and aeromagnetic data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks. Syn-rift Santa Fe Group sediments have a maximum thickness of ˜2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone. Under the Costilla Plains, thickness of these sediments is estimated to reach ˜1.3 km. The Santa Fe Group sediments also reach a thickness of nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. A narrow, north-south-trending structural high beneath San Pedro Mesa separates the graben from the structural depression beneath the Costilla Plains. Aeromagnetic anomalies are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3-3.7 Ma Servilleta basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates indicate patterns of subsidence following eruption of the basalt and show that the Sanchez graben has been the site of maximum subsidence. One of the largest and most pronounced gravity lows in North America lies over the rugged San Juan Mountains in southwestern Colorado. A buried, low-density silicic batholith related to an Oligocene volcanic field coincident with the San Juan Mountains has been the accepted interpretation of the source of the gravity low since the 1970s. However, this interpretation was

  6. Paleomagnetic, Anisotropy of Magnetic Susceptibility, and 40AR/39AR Data from the Cienega Volcano, Cerros del Rio Volcanic Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Foucher, M. S.; Petronis, M. S.; Lindline, J.; Van Wyk de Vries, B.

    2012-12-01

    Cinder cone eruptions are typically interpreted to have formed by the ascension of magma through a simple conduit. Recent field work and laboratory studies on different excavated volcanoes around the world suggest that magma transport within cinder cones can involve a complex system of feeder geometries. We studied the Cienega volcano, a cinder cone in the Cerros del Rio volcanic field, northern New Mexico, in order to better understand the complexity and the evolution of volcanic plumbing systems in the development of cinder cone volcanoes. We hypothesized that cinder cone plumbing systems are inherently complex and involve numerous feeder geometries (e.g. dikes, sills) and flow patterns both towards and away from the central vent complex. The Cienega volcano comprises tephra fall deposits as well as several vents, multiple intrusions, and numerous lava flow sequences. We inspected the magmatic plumbing system using different laboratory methods including paleomagnetic, anisotropy of magnetic susceptibility (AMS), rock magnetic and thin section studies. We collected samples across each outcrop of the feeder system. The dikes are olivine porphyritic basalts with major clinopyroxene, calcic plagioclase feldspar, magnetite, and xenocrystic quartz. Most samples display a trachytic texture with plagioclase crystals showing a preferred orientation parallel to the dike margins. The magnetic information is held predominantly by a cubic phase magnetite with a low- to moderate-Ti composition of Single or Pseudo-Single Domain grains. The AMS results show various flow directions. Three of six dikes yielded magma flow directions away from the vent. The other dikes showed both a subvertical flow, which corresponds to the typical movement of magma in a dike originating from a deeper crustal level, and a downward flow direction. We concluded that magma initially flowed upward from the magma chamber until it encountered flow resistance. At this structural level (the current

  7. The Future of Mexico’s Drug War - Balancing Security and Rule of Law Against Cartel Freedom of Maneuver

    DTIC Science & Technology

    2011-10-28

    Targeted Targeted Effect (Size of Force) Op Michoacan Dec 06 Michoacan La Familia Cartel ops & violence, (4K Mil forces) Op Baja...Cartels such as La Familia have pursued a win-win scenario whereby they co-opt support and effectively out administer the government in providing

  8. Tectonic control of the damaged areas by land subsidence: Ameca, Jalisco Mexico, a study case

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Malagon, A.; Maciel, R.; Alatorre, M. A.; Perez, G.

    2009-04-01

    The Miocene to Quaternary Trans-Mexican Volcanic Belt (TMVB), one of the largest mexican volcanic arcs built on the North America plate, covers about 1000 km along central Mexico from the Pacific ocean to the Gulf of Mexico. The structure of west-central Mexico is dominated by a complex assemblage of crustal blocks bounded by major tectonic structures of the TMVB. These are the NW-SE Tepic-Zacoalco, the N-S Colima, and the E-W Chapala grabens, which separate the Jalisco and Michoacan blocks from the stable North American plate. The three grabens join south of Guadalajara to form what has been long interpreted as an active triple junction. The Tepic-Zacoalco rift is composed of the eastern part of the Plan de Barrancas-Santa Rosa graben and by the Ameca and Zacoalco half-grabens. The Ameca city is located in the Ameca half-graben. From 80´s several houses and buildings (more than 300) have been affected by land subsidence for more than two decades. The damage area follows a specific pattern with NW trend which is similar to the regional faults. The land subsidence is associated with the water extraction. We suggest that the distribution of the damage area is controlled by the fault system in combination with the water extraction. Because of the Ameca half-graben has been affected by historical and present day earthquakes and considering the subsurface geology (sandstones, siltstone intercalated with conglomerates) sudden collapses can be expected.

  9. HAWC @ Mexico

    NASA Astrophysics Data System (ADS)

    Carramiñana, Alberto; González, María Magdalena; Salazar, Humberto; Alfaro, Ruben; Medina Tanco, Gustavo; Valdés Galicia, José; Delepine, David; Zepeda, Arnulfo; Villaseñor, Luis; Mendoza, Eduardo; Nava, Janina; Vázquez, Lilí; Tenorio Tagle, Guillermo; Carrasco, Luis; Silich, Sergey; Rogríguez Liñán, Gustavo; de la Fuente, Eduardo; Page, Dany; Lee, William; Dultzin, Deborah; Benitez, Erika; Ávila Reese, Vladimir; Mendoza, Sergio; Martos, Marco; Hernández Toledo, Héctor; Valenzuela, Octavio; Martínez, Oscar; Fernández, Arturo; Álvarez Ochoa, Cesar; Díaz, Lorenzo; Rosado, Alfonso; Ramírez, Cupatitzio; Menchaca, Arturo; Belmont, Ernesto; Sandoval, Andrés; Martínez, Arnulfo; Grabski, Varlen; Nellen, Lukas; D'Olivo, Juan Carlos; Lara, Alejandro; Caballero, Rogelio; Moreno, Gerardo; Napsuciale, Mauro; Ureña, Luis; Reyes, Marco; Migénes, Victor; Herrera, Gerardo; Saavedra, Oscar; Carrillo, Alejandro; Carrasco Nuñez, Gerardo; Vargas, Carlos

    The High Altitude Water Cerenkov detector HAWC will be a powefull instrument to survey the TeV sky. Mexico has proposed to locate this experiment in the Parque Nacional Pico de Orizaba, between Citlaltepetl and Tliltepetl, host of the Large Millimeter Telescope (LMT). The region has a sizeable technical infrastructure related to the LMT and we recently studied a 4100m location in terms of its feasibility to host HAWC. We present the proposed site location and extension, its water acquisition, experimental and complementary infrastructures.

  10. New Insights on the Evolution of Magmas at Paricutin Volcano, Mexico

    NASA Astrophysics Data System (ADS)

    Rowe, M. C.; Peate, D. W.; Ukstins Peate, I.

    2011-12-01

    Paricutin volcano, located within the Michoacan-Guanajuato volcanic field (MGVF), Mexico, erupted over a 9 year period (1943-1952). Often cited as the classic example of assimilation-fractional crystallization (AFC) processes, bulk compositions of the erupted lavas at Paricutin range from basaltic andesite to andesite and previous studies have correlated this change in bulk composition to increases in 87Sr/86Sr and δ18 O. In this study, we have focused on melt inclusions and new whole rock data to better understand the processes leading to the evolution of magmatic compositions at Paricutin. Olivine- and orthopyroxene hosted melt inclusions are utilized to examine the relative timing of fractionation and contamination during the different eruptive periods of Paricutin. New whole rock trace element compositions, both from this study and the literature, are also incorporated to better determine the initial diversity of magmas and the temporal evolution of bulk compositions. Melt inclusions and whole rock compositions record a complex magmatic history. Initial erupted magmas (Phase 1) are compositionally variable (Ba/Nb from 45-60). Relative to Phase 1, Phase 2 magmas and inclusions have lower Ba/Nb (~38-52) and higher K2O/TiO2 (~1-1.5), inconsistent with models for crustal contamination and fractionation. In addition, Phase 2 lavas have comparable 87Sr/86Sr but distinctive Zr/Y (~6 vs. 7-8) and LREE/HREE ratios (La/YbN: 5.3-5.7 vs. 6.6-7.2) compared to Phase 1 magmas, features that can be explained by small differences in melting. Melt inclusions also record little evidence for magma mixing between Phases 1 and 2, again reflecting the distinctive melt compositions. Phase 3 magmas, in contrast to Phases 1 and 2, record a wide compositional range (SiO2 from ~57-60.5 wt%, Ba/Nb ~53-73) that is consistent with an AFC model. Co-variations in Cl/K and K2O/TiO2 suggest that Phase 3 is assimilating dominantly mid to upper crustal material, similar to xenoliths and basement

  11. Health technology assessment in Mexico.

    PubMed

    Gómez-Dantés, Octavio; Frenk, Julio

    2009-07-01

    The history of health technology assessment (HTA) in Mexico is examined, starting with the efforts to incorporate this topic into the policy agenda and culminating with the recent creation of a specialized public agency. Information was gathered through a bibliographic search and interviews with actors involved in HTA in Mexico. HTA efforts were developed in Mexico since the mid-1980s with the participation both of academics and of policy makers, a relationship that eventually led to the creation of the Center for Technological Excellence within the Ministry of Health. Institutionalization of HTA in resource-constrained settings requires the development of a critical mass of researchers involved in this field, the implementation of information efforts, and the establishment of strong relationships between HTA experts and policy makers.

  12. Numerical simulations of temperature, dehydration, and flow fields associated with subduction of the Cocos plate, and its relation to the occurrence of interplate seismic events in southern Mexico

    NASA Astrophysics Data System (ADS)

    Suenaga, N.; Ji, Y.; Yoshioka, S.; Manea, M.; Manea, V. C.

    2016-12-01

    In southern Mexico, tectonic tremors mainly occur in the "flat slab region, and the last three SSEs in southern Mexico occurred in the shallower region. Besides, there are two seismic gaps of megathrust earthquakes in Guerrero and Oaxaca. To investigate generation mechanisms of megathrust earthquakes, tectonic tremors, and slow slip events (SSEs) in southern Mexico, we performed three-dimensional numerical simulations of temperature and mantle flow associated with subduction of the Cocos plate, and estimated dehydrated water content from the subducting plate. Here we considered retreat of the Middle American trench initiating about 16 Ma as one of the generation mechanisms of the slab flattening. In our model, we introduced the trench retreat effect during only a certain period between 16 Ma and present in order to best fit the observed heat flow data (from Global Heat Flow Database) as well as Curie point depths defined by the 580 ° isotherm. Our preliminary results show that trench rollback has a strong influence on temperature distribution. Models with trench rollback induce a weaker mantle wedge convection cell compared with models with stationary trench. Other parameter that is currently investigated in this study is the rate of trench retreat.

  13. [Update on the epidemiology of mycetoma in Mexico. A review of 3933 cases].

    PubMed

    López-Martínez, Rubén; Méndez-Tovar, Luis J; Bonifaz, Alexandro; Arenas, Roberto; Mayorga, Jorge; Welsh, Oliverio; Vera-Cabrera, Lucio; Padilla-Desgarennes, María Carmen; Contreras Pérez, Cudberto; Chávez, Guadalupe; Estrada, Roberto; Hernández-Hernández, Francisca; Manzano-Gayosso, Patricia

    2013-01-01

    Mycetoma is one of the most frequent chronic subcutaneous infections in many tropical and subtropical regions. To update the epidemiological data of mycetoma cases in Mexico. A survey in the main mycological diagnosis centers in this country was performed. Each mycologist was requested for number of diagnosed mycetoma cases, age, sex, occupation, geographic origin, type of mycetoma, and etiological agents. Until 2012, we have registered 3,933 cases in the last 54 years. Sex distribution corresponds to 75.6% for men and 24.4% for women. In 75.72% is present in adults between 16-50 years old. The predominant work group of patients is farmers (58.41%) followed by housewives (21.79%). Most of patients come from Jalisco, Morelos, Nuevo Leon, Guerrero, Veracruz and Michoacan states. The most affected body areas are limbs (60.29%) and trunk (19.76%). Actinomycetoma has a frequency of 96.52%, and the commonest etiological agent is Nocardia brasiliensis (65.58%). Eumycetoma (3.48%) is mainly caused by Madurella grisea (28.47%) and M. mycetomatis (26.28%). Mycetoma is an under-diagnosed pathology representing a health problem in rural regions and must be attended with more interest by the health institutions.

  14. Extreme Subduction Earthquake Scenarios and their Economical Consequences for Mexico City and Guadalajara, Jalisco, Mexico

    NASA Astrophysics Data System (ADS)

    Chavez, M.; Cabrera, E.; Perea, N.

    2007-05-01

    The destructive effects of large magnitude, thrust subduction superficial (TSS) earthquakes on Mexico City (MC) and Guadalajara (G) has been shown in the recent centuries. For example, the 7/04/1845 a TSS earthquake with Ms 7+ and epicentral distance of about 250 km from MC occurred on the coast of the state of Guerrero, a Maximum Mercalli Modified Intensity (MMI) of IX-X was reported in MC. Furthermore, the 19/09/1985 a Ms 8.1, Mw 8.01, TSS earthquake with epicentral distance of about 340 km from MC occurred on the coast of the state of Michoacan, a maximum MMI of IX-X was reported in MC. Also, the largest, Ms 8.2, instrumentally observed TSS earthquake in Mexico, occurred in the Colima-Jalisco region the 3/06/1932, with epicentral distance of the order of 200 km from G in northwestern Mexico. The 9/10/1995 another similar event, Ms 7.4, Mw 8, with an epicentral distance of about 240 km from G, occurred in the same region and produced MMI IX in the epicentral zone and MMI up to VI in G. The frequency of occurrence of large TSS earthquakes in Mexico is poorly known, but it might vary from decades to centuries [1]. On the other hand, the first recordings of strong ground motions in MC dates from the early 1960´s and most of them were recorded after the 19/09/1985 earthquake. In G there is only one recording of the later event, and 13 for the one occurred the 9/10/1995 [2]. In order to fulfill the lack of strong ground motions records for large damaging TSS earthquakes, which could have an important economical impact on MC [3] and G, in this work we have modeled broadband synthetics (obtained with a hybrid model that has already been satisfactorily compared with observations of the 9/10/1995 Colima-Jalisco Mw 8 earthquake, [4]) expected in MC and G, associated to extreme magnitude Mw 8.5, TSS scenario earthquakes with epicenters in the so-called Guerrero gap and in the Colima-Jalisco zone, respectively. The proposed scenarios are based on the seismic history and up

  15. Sr, Nd and Pb isotope and geochemical data from the Quaternary Nevado de Toluca volcano, a source of recent adakitic magmatism, and the Tenango Volcanic Field, Mexico

    NASA Astrophysics Data System (ADS)

    Martínez-Serrano, Raymundo G.; Schaaf, Peter; Solís-Pichardo, Gabriela; Hernández-Bernal, Ma. del Sol; Hernández-Treviño, Teodoro; Julio Morales-Contreras, Juan; Macías, José Luis

    2004-11-01

    Volcanic activity at Nevado de Toluca (NT) volcano began 2.6 Ma ago with the emission of andesitic lavas, but over the past 40 ka, eruptions have produced mainly lava flows and pyroclastic deposits of predominantly orthopyroxene-hornblende dacitic composition. In the nearby Tenango Volcanic Field (TVF) pyroclastic products and lava flows ranging in composition from basaltic andesite to andesite were erupted at most of 40 monogenetic volcanic centers and were coeval with the last stages of NT. All volcanic rocks in the study area are characterized by a calc-alkaline affinity that is consistent with a subduction setting. Relatively high concentrations of Sr (>460 ppm) coupled with low Y (<21 ppm), along with relatively low HREE contents and Pb isotopic values similar to MORB-EPR, suggest a possible geochemical adakitic signature for the majority of the volcanic rocks of NT. The HFS- and LIL-element patterns for most rocks of the TVF suggest a depleted source in the subcontinental lithosphere modified by subduction fluids, similar to most rocks from the Trans-Mexican Volcanic Belt (TMVB). The isotopic compositions are similar for volcanic rocks of NT and TVF regions ( 87Sr/ 86Sr: 0.703853-0.704226 and 0.703713-0.704481; ɛNd: +4.23-+5.34 and +2.24-+6.85; 206Pb/ 204Pb: 18.55-18.68 and 18.58-18.69; 207Pb/ 204Pb: 15.54-15.62 and 15.56-15.61; 208Pb/ 204Pb: 38.19-38.47 and 38.28-38.50, respectively), suggesting a MORB-like source with low crustal contamination. Metamorphic xenoliths from deeper continental crust beneath NT volcano show isotopic patterns similar to those of Grenvillian rocks of north-central Mexico ( 87Sr/ 86Sr: 0.715653-0.721984, ɛNd: -3.8 to -7.2, 206Pb/ 204Pb: 18.98-19.10, 207Pb/ 204Pb: 15.68-15.69, 208Pb/ 204Pb: 39.16-39.26 and Nd model age (T DM) of 1.2-1.3 Ga). In spite of a thick continental crust (>45 km) that underlies the volcanoes of the study area, the geochemical and isotopic patterns of these rocks indicate low interaction with this crust. NT

  16. Melt inclusions are not reliable proxies for magmatic liquid composition: evidence from crystal-poor andesites and dacites in the Tequila volcanic field, Mexico

    NASA Astrophysics Data System (ADS)

    Frey, H. M.; Lange, R. A.

    2009-12-01

    A compositional study of >200 melt inclusions in plagioclase and orthopyroxene phenocrysts from six crystal-poor (2-5 vol%) andesite and dacite lavas (60-68 wt% SiO2) from the Tequila volcanic field in the Mexico arc is used to evaluate whether melt inclusions in phenocrysts accurately record magmatic liquid compositions. The crystal-poor andesites and dacites were erupted contemporaneously with crystal-poor rhyolites, and there is a continuum in the SiO2 concentration of the erupted magmas. The liquid line of descent defined by the whole-rock compositions ranges from andesite to rhyolite (60-77 wt% SiO2), as illustrated on Harker diagrams. The crystal-poor andesites and dacites are multiply saturated with five to seven mineral phases (plagioclase + orthopyroxene + titanomagnetite + ilmenite + apatite ± augite ± hornblende), most of which crystallized via degassing during magma ascent (Frey and Lange, 2009). By comparison with phase equilibrium experiments from the literature, it is shown that the vast majority of crystals are phenocrysts and not xenocrysts. Textural evidence of rapid crystal growth includes skeletal, hopper, and swallow-tail morphologies and abundant melt inclusions. The inclusions range in size from a few microns to > 50 μm and occur as isolated pockets and extensive channels that mimic the crystal morphology. Inclusions are typically brown glass, with occasional microphenocrysts of titanomagnetite and/or apatite within or adjacent to the melt inclusions. The compositions of the melt inclusions in the plagioclase and orthopyroxene phenocrysts, when plotted on Harker diagrams, vary systematically from one another and from the liquid line of descent defined by the whole rock compositions of erupted magmas. For example, melt inclusions in plagioclase are systematically depleted in Al2O3 relative to the whole rock samples, whereas those in coexisting orthopyroxenes are systematically enriched in Al2O3. The opposite trend is found for FeO, where it

  17. Cancun, Mexico

    NASA Image and Video Library

    2015-11-02

    This image from NASA Terra spacecraft shows Cancun, a resort city on the east side of Mexico Yucatan Peninsula. In 1970, the population was 120 people. The city began as a tourism project in 1974. Since then, it has undergone a comprehensive transformation from being a fisherman's island surrounded by virgin forest and undiscovered shores to being one of the two most well-known Mexican resorts, along with Acapulco. In 1990 the city had grown to 167,000 inhabitants, and by 2014 to 723,000 inhabitants. These two images show the area on March 28, 1985, acquired by Landsat; and May 14, 2014, acquired by ASTER. The images cover an area of 25 x 36 km, and are located at 21.1 degrees north, 86.8 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA20086

  18. United States Department of Energy National Nuclear Security Administration Sandia Field Office NESHAP Annual Report CY2014 for Sandia National Laboratories New Mexico

    SciTech Connect

    evelo, stacie; Miller, Mark L.

    2015-05-01

    This report provides a summary of the radionuclide releases from the United States (U.S.) Department of Energy (DOE) National Nuclear Security Administration facilities at Sandia National Laboratories, New Mexico (SNL/NM) during Calendar Year (CY) 2014, including the data, calculations, and supporting documentation for demonstrating compliance with 40 Code of Federal Regulation (CFR) 61, Subpart H--NATIONAL EMISSION STANDARDS FOR EMISSIONS OF RADIONUCLIDES OTHER THAN RADON FROM DEPARTMENT OF ENERGY FACILITIES. A description is given of the sources and their contributions to the overall dose assessment. In addition, the maximally exposed individual (MEI) radiological dose calculation and the population dose to local and regional residents are discussed.

  19. EPA Collaboration with Mexico

    EPA Pesticide Factsheets

    EPA works with our Mexican neighbors on the U.S.-Mexico Environmental Program, a collaboration between the United States and Mexico to improve the environment and protect the health of the nearly 12 million people living along the border.

  20. Fighting Narcotraffic in Latin America: Mexico and El Salvador - A Comparative Approach

    DTIC Science & Technology

    2015-03-01

    Gulf cartel and the Zetas began an open war which led to alliances with old enemies; the Gulf cartel allied with La Familia , while the Sinaloa cartel...Igancio “Nacho” Colonel; La Familia Michoacana—Nazario Moreno; and the arrest of Eduardo Teodoro “El Teo” Garcia Simental amongst others.77 Despite the...Michoacan has furtherer weakened their power, as La Familia and Los Zetas have expanded their activities in Michoacan neighboring states. Early in the

  1. English Teaching in Mexico.

    ERIC Educational Resources Information Center

    Salazar, Denise

    2002-01-01

    Discusses teaching English in Mexico, a country with important social, cultural, and economic ties to the United States. Looks at the various English teaching situations as well as teacher education for teachers in Mexico. Concludes that the English teaching situation in Mexico reflects great diversity and growth, and that the knowledge of English…

  2. Psychology in Mexico

    ERIC Educational Resources Information Center

    Ruiz, Eleonora Rubio

    2011-01-01

    The first formal psychology course taught in Mexico was in 1896 at Mexico's National University; today, National Autonomous University of Mexico (UNAM in Spanish). The modern psychology from Europe and the US in the late 19th century were the primary influences of Mexican psychology, as well as psychoanalysis and both clinical and experimental…

  3. English Teaching in Mexico.

    ERIC Educational Resources Information Center

    Salazar, Denise

    2002-01-01

    Discusses teaching English in Mexico, a country with important social, cultural, and economic ties to the United States. Looks at the various English teaching situations as well as teacher education for teachers in Mexico. Concludes that the English teaching situation in Mexico reflects great diversity and growth, and that the knowledge of English…

  4. Religious Syncretism in Mexico. Project Mexico.

    ERIC Educational Resources Information Center

    Rhea, David

    This document is an outline for a three-week unit of study focusing on religious syncretism in Mexico as part of a community college course in comparative religions or philosophy of religion. While this outline is intended to give information and direction to the instructor wishing to use Mexico as an example of religious syncretism, unit goals…

  5. Measurements of aerosol absorption and scattering in the Mexico City Metropolitan Area during the MILAGRO field campaign: a comparison of results from the T0 and T1 sites

    NASA Astrophysics Data System (ADS)

    Marley, N. A.; Gaffney, J. S.; Castro, T.; Salcido, A.; Frederick, J.

    2008-07-01

    Measurements of aerosol absorption and scattering were obtained in Mexico City during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign in March 2006. A comparison of aerosol absorption and scattering was obtained in Mexico City at site T0 located in the northern part of Mexico City at the Instituto Mexicano del Petróleo Laboratories and at site T1 located at the Universidad Tecnológica de Tecamac, 18 miles northwest of T0. Hourly averages of aerosol absorption were similar at both sites, ranging from 6 93 Mm-1 with an average of 31 Mm-1 at T0; and from 2 104 Mm-1 with an average of 19 Mm-1 at T1. Aerosol scattering at T0 ranged from 16 344 Mm-1 with an average of 105 Mm-1; while the scattering values at T1 were lower than T0 ranging from 2 136 with an average of 53 Mm-1. Aerosol single scattering albedos (SSAs) were determined at both sites using these data. SSAs at T1 ranged from 0.44 0.90 with an average 0.75 as compared to hose at T0, range 0.51 0.93 with an average of 0.77. Broadband UV-B intensity was found to be higher at site T0, with an average of 64 μW/cm2 at solar noon, than at site T1, which had an average of 54 μW/cm2 at solar noon. Comparisons of clear-sky modeled UV-B intensities with the simultaneous UV-B measurements obtained at site T0 and at site T1 for cloudless days indicate a larger diffuse radiation field at site T0 than at site T1. The determination of aerosol scattering Ångstrom coefficient at T0 suggests the larger diffuse radiation is due to the predominance of submicron aerosols at T0 with aerosol scattering of UV-B radiation peaked in the forward direction, leading to the enhancement observed at ground level.

  6. Discrimination of eolian and pyroclastic-surge processes in the generation of cross-bedded tuffs, Jemez Mountains volcanic field, New Mexico

    SciTech Connect

    Smith, G.A.; Katzman, D. )

    1991-05-01

    Discrimination of pyroclastic deposits emplaced by volcanic processes and reworked pyroclastic sediments is a primary objective of studies in volcaniclastic strata. Cross-bedded tuffs of both eolian and pyroclastic-surge origins are identified within the late Miocene Peralta Tuff Member of the Bearhead Rhyolite, in north-central New Mexico. Distribution, paleoflow directions, grain-size characteristics, and depositional structures permit discrimination of these similar facies. Eolian tuffs exhibits structures diagnostic of eolian sands, are relatively well sorted, and lack both the fine ash and coarse lapilli and bombs typically found in surge deposits. Discrimination between eolian reworked and primary surge pyroclastic deposits is critical for volcanic hazard studies near modern volcanoes and for correct interpretation of proximity to vents in ancient volcaniclastic sequences.

  7. Simulating pumping-induced regional land subsidence with the use of InSAR and field data in the Toluca Valley, Mexico

    NASA Astrophysics Data System (ADS)

    Calderhead, A. I.; Therrien, R.; Rivera, A.; Martel, R.; Garfias, J.

    2011-01-01

    A multidisciplinary approach is presented here for quantifying land subsidence in a heavily pumped aquifer system with complex stratigraphy. The methodology consists in incorporating Terzaghi's 1D instantaneous compaction principle into a 3D groundwater flow model that is then applied and calibrated to reproduce observed hydraulic heads and compaction for the Toluca Valley, Mexico. Differential Interferometric Synthetic Aperture Radar (D-InSAR), a generated 3D-geological model, extensometers, monitoring wells, and available literature are used to constrain the model. The D-InSAR measured subsidence, extensometers, and numerical simulations of subsidence agree relatively well. Simulations show that since regional subsidence began in the mid 1960s there has been up to 2 m of subsidence in the industrial corridor, where heavy pumping and thick clay layers are found. This study shows that an approach using various sources of data is useful in estimating and constraining the vertical component of the inelastic skeletal specific storage.

  8. Morphological and molecular analyses of larval and adult stages of Echinoparyphium recurvatum von Linstow 1873 (Digenea: Echinostomatidae) from central Mexico.

    PubMed

    Sereno-Uribe, A L; Pinacho-Pinacho, C D; Sanchéz Cordero, V; García-Varela, M

    2015-07-01

    In central Mexico, populations of the freshwater snail Physella cubensis were infected with metacercariae from a species of Echinoparyphium (Digenea: Echinostomatidae). In the current study, we describe both larval and adult stages of this species obtained from experimental and natural infections. A total 180 snails were collected from Patzcuaro Lake, Michoacan state in central Mexico in July 2012. In the laboratory snails were placed in individual vials and exposed to light with the aim of observing emergence of cercariae. To obtain metacercariae, uninfected snails (P. cubensis) were exposed to cercariae. Chicks were infected with metacercariae to obtain adults. Nine days post-infection, eggs were recovered and incubated in tap water at room temperature to observe miracidia. Adults obtained from natural and experimentally infected hosts possess a head collar with 45 spines in two alternating rows, confirming the identification as Echinoparyphium recurvatum von Linstow 1873. To test the conspecificity of all stages, sequences of nuclear internal transcribed spacer 1 (ITS1), 5.8S and ITS2 rDNA were obtained from two adult worms recovered from chicks and also a natural avian host, the shoveler duck Anas clypeata, together with five cercarial and four metacercarial isolates from nine snails. The genetic divergence estimated among the 13 isolates was very low, ranging from 0 to 0.6%. Phylogenetic analyses inferred by maximum likelihood and Bayesian methods showed that all isolates of E. recurvatum form a single clade with strong support. The presence of E. recurvatum in P. cubensis and A. clypeata from central Mexico represents new host reports, and extends the distribution range in the Americas.

  9. Defining boundaries across borders: a case study extending a major land resource area into Mexico

    Treesearch

    Rebecca MacEwen; Roy S. Mann; Philip Heilman; Jeffry J. Stone; Alicia Melgoza Castillo; D. Phillip Guertin

    2005-01-01

    Geographic information science (GIS) and field work were applied to extend Major Land Resource Area (MLRA) 41, Southeastern Arizona Basin and Range, from Arizona and New Mexico into Sonora and Chihuahua, Mexico. The result of this analysis is a tentative boundary line that delineates MLRA 41 for both the United States and Mexico based on elevation, soils, temperature,...

  10. USGS field activities 11BHM01 and 11BHM02 on the west Florida shelf, Gulf of Mexico, May and June 2011

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Daly, Kendra L.; Taylor, Carl A.; Barrera, Kira E.

    2014-01-01

    During May and June 2011 the (USGS), in cooperation with (USF), conducted geochemical surveys on the west Florida Shelf to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. The first cruise was conducted from May 3 to 9 (11BHM01) and the second was from June 25 to 30 (11BHM02). To view each cruise's survey lines, please see the Trackline page. Each cruise took place aboard the Research Vessel (R/V) Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed from and returned to Saint Petersburg, Florida. Data collection included sampling of the surface and water column with lab analysis of pH, dissolved inorganic carbon (DIC) or total carbon dioxide (TCO2), and total alkalinity (TA). lLb analysis was augmented with a continuous flow-through system (referred to as sonde data) with a conductivity-temperature-depth (CTD) sensor, which also recorded salinity and pH. Corroborating the USGS data are the vertical CTD profiles (referred to as station samples) collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence and optical backscatter. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts. Two autonomous flow-through (AFT) instruments recorded pH and CO2 every 3-5 minutes on each cruise (referred to as AFT data).

  11. USGS field activities 11BHM03 and 11BHM04 on the west Florida shelf, Gulf of Mexico, September and November 2011

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Daly, Kendra L.; Barrera, Kira E.

    2014-01-01

    During September and November 2011 the (USGS), in cooperation with (USF), conducted geochemical surveys on the west Florida Shelf to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. The first cruise was conducted from September 20 to 28 (11BHM03) and the second was from November 2 to 4 (11BHM04). To view each cruise's survey lines, please see the Trackline page. Each cruise took place aboard the Research Vessel (R/V) Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed from and returned to Saint Petersburg, Florida. Data collection included sampling of the surface and water column with lab analysis of pH, dissolved inorganic carbon (DIC) or total carbon dioxide (TCO2), and total alkalinity (TA). lLb analysis was augmented with a continuous flow-through system (referred to as sonde data) with a conductivity-temperature-depth (CTD) sensor, which also recorded salinity and pH. Corroborating the USGS data are the vertical CTD profiles (referred to as station samples) collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence and optical backscatter. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts. Two autonomous flow-through (AFT) instruments recorded pH and CO2 every 3-5 minutes on each cruise (referred to as AFT data).

  12. USGS Field Activities 11CEV01 and 11CEV02 on the West Florida Shelf, Gulf of Mexico, in January and February 2011

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Daly, Kendra L.; Taylor, Carl A.

    2014-01-01

    During January and February 2011 the U.S. Geological Survey (USGS), in cooperation with the University of South Florida (USF), conducted geochemical surveys on the west Florida Shelf. Data collected will allow USGS and USF scientists to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. This work is part of a larger USGS study on Climate and Environmental Variability (CEV). The first cruise was conducted from January 3 – 7 (11CEV01) and the second from February 17 - 27 (11CEV02). To view each cruise's survey lines, please see the Trackline page. Both cruises took place aboard the R/V Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed and returned from Saint Petersburg, Florida. Data collection included sampling of the surface and water column (referred to as station samples) with lab analysis of pH, dissolved inorganic carbon (DIC), and total alkalinity. Augmenting the lab analysis was a continuous flow-through system with a Conductivity-Temperature-Depth (CTD) sensor, which also recorded salinity, and pH. Corroborating the USGS data are the vertical CTD profiles collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence, optical backscatter, and transmissometer. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts.

  13. Assessment of MODIS-EVI, MODIS-NDVI and VEGETATION-NDVI composite data using agricultural measurements: an example at corn fields in western Mexico.

    PubMed

    Chen, Pei-Yu; Fedosejevs, Gunar; Tiscareño-López, Mario; Arnold, Jeffrey G

    2006-08-01

    Although several types of satellite data provide temporal information of the land use at no cost, digital satellite data applications for agricultural studies are limited compared to applications for forest management. This study assessed the suitability of vegetation indices derived from the TERRA-Moderate Resolution Imaging Spectroradiometer (MODIS) sensor and SPOT-VEGETATION (VGT) sensor for identifying corn growth in western Mexico. Overall, the Normalized Difference Vegetation Index (NDVI) composites from the VGT sensor based on bi-directional compositing method produced vegetation information most closely resembling actual crop conditions. The NDVI composites from the MODIS sensor exhibited saturated signals starting 30 days after planting, but corresponded to green leaf senescence in April. The temporal NDVI composites from the VGT sensor based on the maximum value method had a maximum plateau for 80 days, which masked the important crop transformation from vegetative stage to reproductive stage. The Enhanced Vegetation Index (EVI) composites from the MODIS sensor reached a maximum plateau 40 days earlier than the occurrence of maximum leaf area index (LAI) and maximum intercepted fraction of photosynthetic active radiation (fPAR) derived from in-situ measurements. The results of this study showed that the 250-m resolution MODIS data did not provide more accurate vegetation information for corn growth description than the 500-m and 1000-m resolution MODIS data.

  14. A water-budget approach to estimating potential groundwater recharge from two domestic sewage disposal fields in eastern Bernalillo County, New Mexico, 2011-12

    USGS Publications Warehouse

    Crilley, Dianna M.; Collison, Jake W.

    2015-08-04

    During this study, the disposal fields at sites A and B received a measured volume of effluent from two-person domestic residences equipped with an onsite low-pressure dosing system. A combined evapotranspiration measurement and modeling technique was used to estimate the amount of evapotranspirative loss from the disposal field and from the surrounding terrain. A portable hemispherical flux chamber was used to measure evapotranspiration at fixed locations on the disposal fields and on the surrounding terrain at sites A and B. Data from hemispherical flux chamber measurements were used to calibrate a Penman-Monteith modeled evapotranspiration rate on the disposal field and on the surrounding terrain at site A from January 1, 2011, to December 31, 2011, and from January 1, 2012, to December 31, 2012, and at site B from January 1, 2011, to December 31, 2011. Micrometeorological and soil data from instrumentation on the disposal fields and on the surrounding terrain at sites A and B were used as input data into the Penman-Monteith equation. The mean potential recharge from disposal field effluent during 2011–12 at sites A and B was 63 percent of the volume of effluent dosed to the disposal field.

  15. Mexico Country Analysis Brief

    EIA Publications

    2016-01-01

    Mexico is one of the largest producers of petroleum and other liquids in the world. Mexico is also the fourth-largest producer in the Americas after the United States, Canada, and Brazil, and an important partner in U.S. energy trade. In 2015, Mexico accounted for 688,000 barrels per day (b/d), or 9%, of U.S. crude oil imports.

  16. National Security Policy: Mexico.

    DTIC Science & Technology

    1986-04-01

    military service or government agency. ------- NATIONAL SECURITY POLICY: MEXICO L TIC BY OELEc-re LIEUTENANT COLONEL HUGH SCRUGGS JUL 2 8 96 DISTRIBUTION...PERIOD COVERED National Security Policy: Mexico SMDENr EnSAY 6. PERFORMING ORG. REPORT NLMBER 7. AUTNOR(&) S. CONTRACT OR GRANT NUMBER(s) LTC Hugh...national security and sovereignty of Mexico and to determine the capability of the Nexican armed forces to meet these threats. Through literary research

  17. A Strategy for Mexico?

    DTIC Science & Technology

    2011-06-10

    2011, Small Wars Foundation June 10, 2011 A Strategy for Mexico ? by Johnny M. Lairsey Jr. For over a century, United States foreign policy...maintaining international relations and protecting ourselves and our allies against transnational threats.3 Given the existing conditions in Mexico ...organizations and help to improve the conditions in Mexico . However, before taking action the United States must clearly articulate the purpose of why it is

  18. Mexico`s basins could provide niches for various sized firms

    SciTech Connect

    Baker, G.; Wilson, J.L.

    1996-11-18

    The recent Shell Oil Co.-led exploratory well in 7,000 ft of water in the Gulf of Mexico off Brownsville, Texas, and close to Mexican territory, initially provoked a controversy in Mexico. The announcement of the Baha well reminded Mexicans that the US Senate has not yet ratified the draft treaty to define territorial and resource boundaries. News of the well was portrayed in mexico as poaching and old-fashioned American imperialism. Although subsequent reports confirmed that the well is unequivocally in US waters, the initial confusion added to a growing dilemma in professional geological circles and with a few federal, state, and local officials. In this discussion, which is part of a larger study, the authors wish to clarify some of the issues in the upstream policy debate in Mexico. They do this by visualizing a counter-factual condition: that worldwide E and P patterns and norms exist in Mexico. The discussion will not treat the implementation of such patterns or norms (e.g., by reference to the Venezuelan or Argentine models). For this discussion they assume simply that worldwide production practices and agreements exist in Mexico. Just as important, they assume that industrial efficiencies, by producer type, are the principal drivers of the allocation of E and P resources in Mexico. The authors discuss the illustrative areas and fields of hydrocarbon production, actual and potential, from the perspective of the advantages and limitations associated with the various categories of explorationists and producers.

  19. [Mexico and Japanese emigrants].

    PubMed

    Yanaguida, T; Akagui, T

    1995-08-01

    "Japanese immigration to Mexico began in the last decade of the 19th century with a coffee growing project, and proved a failure. Subsequent attempts [at] sending contract labor migrants by emigration agencies, which involved 10,000 Japanese emigrants in 1901-1908, were also unsuccessful, and Mexico turned for Japanese emigrants into a short step on their way to the United States. The evolution of those who remained in Mexico and the different developments of the Japanese communities in Mexico [are] analyzed here until the period after World War II." (SUMMARY IN ENG) excerpt

  20. Eruptive activity of enigmatic medium-sized volcanoes in the Michoacán-Guanajuato Volcanic Field (MGVF), Central Mexico: The case of El Metate

    NASA Astrophysics Data System (ADS)

    Chevrel, M.; Siebe, C.; Guilbaud, M. N.

    2014-12-01

    The MGVF has a total area of ca. 40,000 km2 and is well known for being the host of the only two monogenetic volcanoes in Mexico that were born in historical times: Jorullo (1759-1774) and Paricutin (1943-1952). Another particularity of the MGVF is its high number of eruptive vents with over 1000 small monogenetic cones and associated lava flows (average vol. of 0.021 km3) and ca. 400 medium-sized volcanoes (average vol. from 0.5 to 50 km3). Most of these medium-sized volcanoes may be characterized as shields that were produced dominantly by effusive activity as opposed to the small cones formed also by explosive phases of activity. The products of the small cones range from olivine basalts to andesites whereas the medium-sized volcanoes are restricted to a smaller compositional range in the andesitic domain. Although the medium-sized volcanoes are more sparsely distributed in time and space and less abundant than the small cones, the risks associated with renewal of this type of activity should not be neglected. This study focuses on El Metate which is probably the youngest shield of the MGVF (< 3,700 y. BP). Unlike a typical shield volcano composed of a succession of thin fluid basaltic flows, El Metate consists of well-preserved >60 m thick andesite flows distributed radially around a summit dome. Detailed mapping and sampling allowed us to reconstruct its eruptive activity and the time sequence of lava flow emplacement. We have identified 13 individual lava flows with lengths ranging between 3 and 15 km covering 103 km2 and average thicknesses between 60 and 150 m. Individual volumes range between 0.5 and 3.5 km3 for a total of 11 to 15 km3. Estimates of flow emplacement parameters indicate maximum average effusion rates ranging between 15 and 100 m3.s-1 and a cumulative duration from 15 to 30 years. Such a short emplacement time is comparable to the historical monogenetic eruption of nearby Paricutin volcano (9 years) but the erupted volume of lava is

  1. Paleomagnetism of the Eastern Alkaline Province (Mexico): contribution to the time-averaged field global database and geomagnetic instability time scale

    NASA Astrophysics Data System (ADS)

    Goguitchaichvili, Avto; Petronille, Marie; Henry, Bernard; Valdivia, Luis Alva; Morales, Juan; Urrutia-Fucugauchi, Jaime

    2007-07-01

    We report a detailed paleomagnetic and rock-magnetic study of 19 independent lava flows belonging to the Eastern Alkaline Province (EAP) in Mexico. In total, 162 oriented samples were collected in four areas (Sierra de Tantima-Alamo, Tlanchinol, Chiconquiaco-Palma Sola and Poza Rica). All sites analyzed in this study were previously dated by means of the unspiked K-Ar geochronological method (Ferrari et al., J. Volcanol. Geotherm. Res., 146, 284-306, 2005) and span from 14.6 to 1.5 Ma. Rock-magnetic experiments point to simple magnetic mineralogy. In most cases, the remanence is carried by Ti-poor titanomagnetite of pseudosingle-domain grain size. In a few cases, Ti-rich titanomagnetites are responsible for the magnetization. The characteristic paleodirections are successfully isolated for all of the studied units. The mean paleodirection, discarding two intermediate polarity sites, is D=359.5°, I=32.9°, n=17, k=30, α95=6.7°. This direction is practically undistinguishable from the expected Mio-Pliocene paleodirections, as derived from reference poles for the North American polar wander curve, and is in agreement with the previously reported directions from the western Trans-Mexican Volcanic Belt. This suggests that no major tectonic rotation occurred in studied area since the middle Miocene to Present. The paleosecular variation is estimated through the study of the scatter of virtual geomagnetic poles, giving S F=12.7 with S U=16.5 and S L=10.3 (upper and lower limits, respectively). These values are consistent with those predicted by the latitude-dependent variation model of McFadden et al. ( Geophys. Res., 93, 11583-11588, 1991) for the last 5 Myr. Eleven sites yielded reverse magnetic polarity, six are normally magnetized and two lava flows provided apparently intermediate paleodirections. An interesting feature of the paleomagnetic record obtained from EAP volcanics is that two independent lava flows, dated as 2.04±0.04 and 1.97±0.04 Ma, respectively

  2. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    SciTech Connect

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S

    2011-03-03

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  3. Land subsidence in the Cerro Prieto Geothermal Field, Baja California, Mexico, from 1994 to 2005: An integrated analysis of DInSAR, leveling and geological data

    NASA Astrophysics Data System (ADS)

    Sarychikhina, Olga; Glowacka, Ewa; Mellors, Robert; Vidal, Francisco Suárez

    2011-07-01

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994-1997 and 1997-2006) and detailed geological information in order to improve understanding of the temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the changes in spatial pattern and rate of the subsidence are correlated with the development of the Cerro Prieto Geothermal Field.

  4. Sierra Madre Oriental, Mexico

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This view of the Sierra Madre Oriental, Mexico (26.5N, 102.0W) west of Monclova, shows a mining region of northern Mexico. Mine tailings can be seen on the mountain slopes and in the valley floor. In addition to mining activity, several irrigated agricultural areas supporting the local communities can be seen in the area.

  5. Gulf of Mexico

    Atmospheric Science Data Center

    2014-05-15

    article title:  Continued Spread of Gulf of Mexico Oil Slick       View ... passed over the Deepwater Horizon oil slick in the Gulf of Mexico on May 8, 2010, at approximately 16:50 UTC (11:50 a.m. local time), then ...

  6. English Teaching Profile: Mexico.

    ERIC Educational Resources Information Center

    British Council, London (England). English Language and Literature Div.

    This profile of the English language teaching situation in Mexico examines the role of English in society and in the educational system. It is noted that the extent to which English is used in Mexico is affected by the country's proximity to the United States. The educational system is described, with emphasis on English instruction which begins…

  7. Sierra Madre Oriental, Mexico

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This view of the Sierra Madre Oriental, Mexico (26.5N, 102.0W) west of Monclova, shows a mining region of northern Mexico. Mine tailings can be seen on the mountain slopes and in the valley floor. In addition to mining activity, several irrigated agricultural areas supporting the local communities can be seen in the area.

  8. Graduate Education in Mexico.

    ERIC Educational Resources Information Center

    Martinez, Enrico N.; Gomez, Roman

    1982-01-01

    The needs, deficiencies, and possible solutions for undergraduate education of chemical engineers in Mexico were discussed in Volume XVI (Number 3) of this journal. In this paper, the authors extend their comments to the status of graduate education of chemical engineers in Mexico, focusing on the masters program. (Author/JN)

  9. Graduate Education in Mexico.

    ERIC Educational Resources Information Center

    Martinez, Enrico N.; Gomez, Roman

    1982-01-01

    The needs, deficiencies, and possible solutions for undergraduate education of chemical engineers in Mexico were discussed in Volume XVI (Number 3) of this journal. In this paper, the authors extend their comments to the status of graduate education of chemical engineers in Mexico, focusing on the masters program. (Author/JN)

  10. The Tarahumara of Mexico.

    ERIC Educational Resources Information Center

    Paciotto, Carla

    This paper reviews factors contributing to the loss of language and culture of the Tarahumara people of Mexico and describes a program aimed at preserving Tarahumara language and culture. The Tarahumara people reside in the Sierra Tarahumara in the northern state of Chihuahua, Mexico. Although the Tarahumara people successfully avoided…

  11. Drought Studies For Mexico

    NASA Astrophysics Data System (ADS)

    Magana, V.

    2007-05-01

    Drought constitutes one of the major threats for a number of socioeconomic sectors in Mexico. Meteorological drought occurs in various temporal and spatial scales that range from a few weeks in the tropical Mexico to decades in northern Mexico. Historically, these long term droughts have had a negative impact, not only in economic activities, but in the lives of Mexicans as well. In general, short term droughts over central southern Mexico are related to El Niño conditions. However, drought may also occur when an anomalously low number of easterly waves reach the Caribbean and Mexico. El Niño and easterly wave activity may be related by the intensification of the Caribbean Low Level Jet. However, the role of this form of transient activity as a drought trigger in Mexico has not been explored in depth. The present analysis explores the possibility of more than one form of forcing to explain drought in Mexico on various spatial and temporal scales, as well as in various regions. Such approach to the study of drought may prove useful to diagnose why certain general circulation models are unable of reproducing drought patterns over Mexico.

  12. New Mexico's forest resources, 2008-2012

    Treesearch

    Sara A. Goeking; John D. Shaw; Chris Witt; Michael T. Thompson; Charles E. Werstak; Michael C. Amacher; Mary Stuever; Todd A. Morgan; Colin B. Sorenson; Steven W. Hayes; Chelsea P. McIver

    2014-01-01

    This report presents a summary of the most recent inventory of New Mexico’s forests based on field data collected between 2008 and 2012. The report includes descriptive highlights and tables of area, numbers of trees, biomass, volume, growth, mortality, and removals. Most sections and tables are organized by forest type or forest type group, species group, diameter...

  13. Constructing an Identity: Environmental Educators in Mexico

    ERIC Educational Resources Information Center

    Amaya, Silvia Fuentes

    2004-01-01

    The environmental education field in Mexico is a relatively new social space characterized by wide discursive proliferation and organized by regional hegemonies. In this context, a plurality of identification processes has taken place. There is not a singular environmental educator identity but a multiplicity of local definitions. In this paper, I…

  14. Education in Mexico. Bulletin, 1956, No. 1

    ERIC Educational Resources Information Center

    Johnston, Marjorie C.

    1956-01-01

    "Education in Mexico," one of the series of basic studies on education in the American Republics undertaken by the Office of Education, has been prepared with the interests of the following groups in mind: (1) Persons working in the field of Inter-American educational relations; (2) Those specializing in Latin American area and language…

  15. Education in Mexico. Bulletin, 1956, No. 1

    ERIC Educational Resources Information Center

    Johnston, Marjorie C.

    1956-01-01

    "Education in Mexico," one of the series of basic studies on education in the American Republics undertaken by the Office of Education, has been prepared with the interests of the following groups in mind: (1) Persons working in the field of Inter-American educational relations; (2) Those specializing in Latin American area and language…

  16. Petroleum and Mexico's future

    SciTech Connect

    Falk, P.S.

    1987-01-01

    Addressing the effects of the 1982 crisis, through the late 1980s, on Mexico's economic and political systems and assessing the country's potential for entering a period of strong economic growth, contributors to this volume focus on oil, the primary source of Mexico's foreign exchange earnings, and on trade with the U.S., the primary means for earning foreign exchange. The authors argue that the problems Mexico faced during the crisis period are not over; indeed, the most difficult challenges lie ahead. For the remainder of the century Mexico must earn adequate revenue to service a substantial debt and to permit the economy to grow at a rate that provides opportunity for a labor force already enduring a high rate of unemployment and rising inflation. Contributors agree that the key to Mexico's economic and political stability will be control of inflation, unemployment, and large public sector deficits.

  17. Two new species of Phyllodistomum Braun, 1899 (Digenea: Gorgoderidae), from freshwater fishes (Cyprinodontiformes: Goodeidae: Goodeinae) in central Mexico: An integrative taxonomy approach using morphology, ultrastructure and molecular phylogenetics.

    PubMed

    Pérez-Ponce de León, Gerardo; Martínez-Aquino, Andrés; Mendoza-Garfias, Berenit

    2015-09-07

    An integrative taxonomy approach is used to characterise the diversity of gorgoderid trematodes that parasitize freshwater fishes of the subfamily Goodeinae in central Mexico. Records of Phyllodistomum sp. and Dendrorchis sp. from the urinary bladder of goodeines have been previously published, although the identification at species level was not achieved. A few specimens were collected and fixed to conduct a scanning electron microscopy study, and to obtain sequences of a mitochondrial (COI) and nuclear (28S rRNA) gene, to be analysed in the context of the molecular phylogeny of gorgoderid trematodes. Based on the new findings, two new species of Phyllodistomum Braun, 1899 are described. Phyllodistomum cribbi n. sp. was found in Zoogoneticus quitzeoensis (Bean), Allotoca zacapuensis Meyer, Radda & Domínguez-Domínguez, Hubbsina turneri de Buen and Z. purhepechus Domínguez-Domínguez, Pérez-Rodríguez & Doadrio from Zacapu Lake, and La Luz Spring, in Michoacan, central Mexico. Phyllodistomum wallacei n. sp. parasitized Xenotaenia resolanae Turner, Ilyodon furcidens (Jordan & Gilbert), and Allodontichthys tamazulae Turner from the Cuzalapa, Ayuquila and Tamazula Rivers in Jalisco, western Mexico. These species are compared with several freshwater Phyllodistomum species from different areas of the world, especially a group of eight species that comprise a monophyletic clade in recent phylogenetic hypotheses of the Gorgoderidae Looss, 1899. The two new species are distinguished from other close relatives by the combination of morphological traits such as the body shape, sucker ratio, shape of the gonads, and extension of intestinal ceca. The new species are distinct in some ultrastructural characters of the body surface when compared with those species where scanning electron micrographs (SEM) and/or microphotographs are available. Data of two molecular markers (28S rRNA and COI genes) demonstrate that the two new species are distinct from each other and from those

  18. Macroseismological And Paleoseismological Studies In The Active Segments Of The Morelia Acambay Fault System, Mexico

    NASA Astrophysics Data System (ADS)

    Garduño-Monroy, V. H.; Rodriguez-Pascua, M. A.; Israde-Alcantara, I.; Hernandez-Madrigal, V. M.

    2007-05-01

    Paleoseismological studies along several faults of the Morelia-Acambay system show clear evidence of its seismicity. In the Acambay region, four seismic events were identified during the Pliocene Pleistocene; two linked to large sub aquatic landslides, and two to liquefaction processes. The two seismic events associated to slumps were also recognized in the Ixtlahuaca, Mexico, region; meaning these were relevant seismic events at a regional level. Their magnitudes were above 5 degrees. Because these latter events are located in the same column, they could be of aid in knowing recurrence periods. In the southern portion of the Lake of Patzcuaro region a collapse was identified generating a rock avalanche nearly 29,000 years ago. This collapse is associated to an earthquake of magnitude above 7 degrees, which decreased the lake's extension and resulted in morphology of small hummocks. The Purhepecha term Jaracuaro means "place that emerges" and is the name of a former island where Pre Hispanic settlements occurred. The island is exclusively made up of lacustrine sequences that rose above 50m in height, georadar and vertical electrical signal (VES) studies do not reveal intrusive bodies associated to this deformation. Isosists of the 1845 and 1858 seismic events were reconstructed in the modified Mercalli scale through several historical studies in a number of municipalities in the State of Michoacan. The results indicate isosistes of IX degrees in Patzcuaro, where the earthquake caused the collapse of the basilica. During the 1858 earthquake the water level in the southern portion of the Lake of Patzcuaro raised over 2m and the destruction of 120 adobe houses is related to the generation of a tsunami. This seismic event is being characterized in wells and ditches dugs around Patzcuaro Lake. The region of Patzcuaro has experienced a number of magmatic and tectonic events that undoubtedly modified the conditions of the lake regarding its sedimentology and anthropogenic

  19. Relationship between Overpressure and the Formation of Hydrocarbon-Rich Solitary Waves during Sedimentary Basin Diagenesis: A Case Study of the Eugene Island 330 Field in the Gulf of Mexico Basin

    NASA Astrophysics Data System (ADS)

    Joshi, A.; Appold, M. S.; Nunn, J. A.

    2011-12-01

    Hydrocarbons in shallow (< 1 km depth) Pleistocene sand reservoirs of the Eugene Island 330 field in the northern Gulf of Mexico basin are thought to have originated from Early Tertiary source sediments at depths of about 4.5 km. Despite the low permeability of the intervening sediments, hydrocarbons appear to have moved rapidly through these sediments, most likely as discrete pressure pulses (solitary waves) along the Red growth fault system. The purpose of the present research was to evaluate the mechanics of solitary wave formation and movement during sedimentation, diagenesis, and source rock maturation in the Eugene Island hydrocarbon field. A detailed two-dimensional model coupling sedimentation, compaction, hydrocarbon generation, heat transport, and multi-phase fluid flow predicted overpressures of 50 MPa by 0.5 Ma in the hydrocarbon source sediments, with about 93% of the overpressure caused by compaction disequilibrium and the remainder by hydrocarbon generation. Movement along the Red growth fault was rapid enough to cause a pressure decrease of several MPa from the upthrown block to the downthrown block, consistent with field observations. The average pressure generation rate at the base of the Red fault during the period of hydrocarbon formation was predicted to be 9.6x10-7 Pa/s. However, for the most likely values of fault permeability, basal heat flow, and organic carbon content of the source rocks, too little hydrocarbon was able to migrate along the Red fault by conventional Darcian flow and accumulate in the Pleistocene reservoirs relative to field observations. Only when the permeability of the shale-bounded portions of the Red fault was increased by an order of magnitude, the basal heat flow was increased from 60 to 70 mW/m2, and the organic carbon content of the source rocks was increased from 5% to 10% was hydrocarbon transport by conventional Darcian flow through the Red fault great enough to accumulate in the reservoirs in amounts

  20. Source parameters of the Pinotepa Nacional, Mexico, earthquake of 27 March, 1996 (Mw = 5.4) estimated from near-field recordings of a single station

    NASA Astrophysics Data System (ADS)

    Singh, S.K.; Pacheco, J.; Courboulex, F.; Novelo, D.A.

    We use near-field accelerograms recorded by the very broadband seismographic station of PNIG to locate the Pinotepa Nacional earthquake of 27 March, 1996 (Mw = 5.4) and to determine its source parameters. The data from PNIG on P and S arrival times, the azimuth of the arrival of P wave, and the angle of incidence of the P wave at the free surface permit the determination of the location (16.365° N, 98.303° W, depth = 18 km) and the origin time (12:34;48.35) of the earthquake.The displacement seismograms of the earthquake clearly shows contribution from the near-field terms. We compute a suite of synthetic seismograms for local mechanisms in the vicinity of the mechanism reported by the U.S. Geological Survey (USGS) and compare them with the observed seismograms at PNIG. The point whose synthetics fit the observed records well has the following parameters: seismic moment, M0 = 1.2 × 1024 dyne-cm; source time function: a triangular pulse of 0.9 sec duration; fault plane: strike = 291°, dip = 10°, and rake = 80°. The location and the source parameters obtained from the analysis of PNIG records differ significantly from those reported by the USGS. This demonstrates again, what has been shown by some previous researchers, that high-quality recordings from a single near-field station can considerably improve the estimation of the source parameters of an earthquake.

  1. 3-D Deformation Field Of The 2010 El Mayor-Cucapah (Mexico) Earthquake From Matching Before To After Aerial Lidar Point Clouds

    NASA Astrophysics Data System (ADS)

    Hinojosa-Corona, A.; Nissen, E.; Arrowsmith, R.; Krishnan, A. K.; Saripalli, S.; Oskin, M. E.; Arregui, S. M.; Limon, J. F.

    2012-12-01

    The Mw 7.2 El Mayor-Cucapah earthquake (EMCE) of 4 April 2010 generated a ~110 km long, NW-SE trending rupture, with normal and right-lateral slip in the order of 2-3m in the Sierra Cucapah, the northern half, where the surface rupture has the most outstanding expression. Vertical and horizontal surface displacements produced by the EMCE have been addressed separately by other authors with a variety of aerial and satellite remote sensing techniques. Slip variation along fault and post-seismic scarp erosion and diffusion have been estimated in other studies using terrestrial LiDAR (TLS) on segments of the rupture. To complement these other studies, we computed the 3D deformation field by comparing pre- to post-event point clouds from aerial LiDAR surveys. The pre-event LiDAR with lower point density (0.013-0.033 pts m-2) required filtering and post-processing before comparing with the denser (9-18 pts m-2) more accurate post event dataset. The 3-dimensional surface displacement field was determined using an adaptation of the Iterative Closest Point (ICP) algorithm, implemented in the open source Point Cloud Library (PCL). The LiDAR datasets are first split into a grid of windows, and for each one, ICP iteratively converges on the rigid body transformation (comprising a translation and a rotation) that best aligns the pre- to post-event points. Testing on synthetic datasets perturbed with displacements of known magnitude showed that windows with dimensions of 100-200m gave the best results for datasets with these densities. Here we present the deformation field with detailed displacements in segments of the surface rupture where its expression was recognized by ICP from the point cloud matching, mainly the scarcely vegetated Sierra Cucapah with the Borrego and Paso Superior fault segments the most outstanding, where we are able to compare our results with values measured in the field and results from TLS reported in other works. EMC simulated displacement field for a

  2. Star formation in the "Gulf of Mexico"

    NASA Astrophysics Data System (ADS)

    Armond, T.; Reipurth, B.; Bally, J.; Aspin, C.

    2011-04-01

    We present an optical/infrared study of the dense molecular cloud, L935, dubbed "The Gulf of Mexico", which separates the North America and the Pelican nebulae, and we demonstrate that this area is a very active star forming region. A wide-field imaging study with interference filters has revealed 35 new Herbig-Haro objects in the Gulf of Mexico. A grism survey has identified 41 Hα emission-line stars, 30 of them new. A small cluster of partly embedded pre-main sequence stars is located around the known LkHα 185-189 group of stars, which includes the recently erupting FUor HBC 722.

  3. 39Ar/40Ar Chronology and Volumes of Eruptive Products Over the Last 1 Myr in the Tequila Volcanic Field, Jalisco, Mexico

    NASA Astrophysics Data System (ADS)

    Lewis-Kenedi, C. B.; Lange, R. A.; Hall, C. M.; Delgado-Granados, H.

    2002-12-01

    The Tequila volcanic field, located within the western Trans-Mexican arc, covers an area of 1036 km2 and includes a central, andesitic stratocone, Volc\\­_{a}n Tequila, as well as cinder cones, domes, and fissure-fed flows. Sixty-nine high precision 39Ar-40Ar dates reveal that major activity in the Tequila volcanic field began at approximately 1 Ma. From 1 Ma to 200 ka, rhyolite (> 73 wt. % SiO2) and alkali basalt (­š 51 wt. % SiO2) were the only compositions erupted in significant volumes (29 +/- 5.7 km3 and 12 +/- 1.2 km3, respectively). At approximately 200 ka, the andesite comprising Volc\\­_{a}n Tequila erupted within 30-40 kyr, producing a volume of 30 +/- 2.0 km3. Additional andesitic flows (11 +/- 1.4 km3) erupted to the northwest and southeast of the stratocone between 140 and 20 ka. The total volume of dacite that erupted at the Tequila volcanic field is small (1.3 +/- 0.03 km3) and occurred largely (88%) within the last 70 kyrs. Unlike the andesites and dacites, the basalts and rhyolites did not erupt within narrow time intervals, but extruded over the entire last 1 Myr, producing a total volume of 12.6 +/- 1.2 km3 and 32 +/- 6.1 km3, respectively. This detailed eruptive history, combined with the observed phenocryst assemblages (0-10 vol. %) in the small-volume andesite, dacite, and alkali basalt flows, suggest that they were erupted directly from the lower (or middle) crust, without prior storage in an upper crustal chamber. In contrast, the voluminous burst of andesitic volcanism that produced the phenocryst-rich (35-45 vol. %) lavas of Volc\\­_{a}n Tequila was likely fed from a short-lived (­š 40 kyrs) upper crustal chamber. This scenario is supported by the complex, disequilibrium textures seen in the phenocryst assemblage of the Volc\\­_{a}n Tequila lavas, indicative of magma mingling within an upper crustal chamber (Wallace and Carmichael, 1994). The total volume of erupted material at the Tequila volcanic field is 89 +/- 12 km3, of which

  4. Mineralogical and geochemical consequences of the long-term presence of CO2 in natural reservoirs: An example from the Springerville-St. Johns Field, Arizona, and New Mexico, U.S.A

    USGS Publications Warehouse

    Moore, J.; Adams, M.; Allis, R.; Lutz, S.; Rauzi, S.

    2005-01-01

    The Springerville-St. Johns CO2 field in eastern Arizona and western New Mexico is one of more than a dozen gas fields developed within the Colorado Plateau and Southern Rocky Mountain region. Extensive travertine (CaCO3) deposits record a long history of CO2 migration and leakage to the atmosphere. The oldest travertine deposits may have formed during the initial filling of the CO2 reservoir when groundwaters exsolved CO2 upon reaching the surface. The youngest travertine deposits are associated with springs on the floor of the Little Colorado River valley, but travertine deposition appears to be insignificant today. Older deposits occur up to 325 m above the valley floor. Geologic relationships suggest travertine deposition began in the late Pleistocene after volcanic activity ended at ???0.3 Ma. Most of the CaCO3 could have been derived from dissolution of the underlying limestones and dolomites. Interactions between the reservoir fluids and rocks were observed in core samples from one of the intervals that produced dry gas. These reactions resulted in the dissolution of carbonate cements and detrital feldspars and the formation of dawsonite and kaolinite. Geochemical simulations suggest that the dawsonite could have been deposited when the CO2 fugacity reached 20 bars and that the kaolinite formed as the CO2 fugacity decreased. Corrosion of drill pipe by acidic waters and a pronounced HCO3 anomaly above the CO2 reservoir provide evidence of a continuing flux of CO2 from depth. CO2 storage occurs primarily as dissolved carbonate species and as gas accumulations. Only a small percentage of the CO2 was sequestered in secondary minerals. ?? 2005 Elsevier B.V. All rights reserved.

  5. Rabies control in Mexico.

    PubMed

    Lucas, C H Alvarez; Pino, F Vargas; Baer, G; Morales, P Kuri; Cedillo, V Gutiérrez; Blanco, M A Llanas; Avila, M Hernández

    2008-01-01

    Rabies in dogs was unknown in the Americas before the arrival of the Spanish "Conquistadores". Until the mid-1980s rabies in animals and, in turn in humans, changed little from year to year, with the number of dog vaccinations reported annually rarely reaching one million. In Mexico, the national rabies control programme using mass parenteral vaccination of dogs started in 1990 with about seven million dogs vaccinated the same year. The number of vaccinated dogs exceeded 10 and 15 million in 1995 and 2005, respectively. Modern cell culture-based inactivated rabies virus vaccines were used. A key factor for the success of the dog rabies control program was the supply of potent canine rabies vaccines. Between 1990 and 2005, more than 150 million vaccine doses from 300 lots were administered. Each lot was tested for potency prior to use in the field. The required minimum content of rabies virus antigen for vaccines was 2 IU, in accord with WHO standards. Testing revealed antigen contents ranging from 3.28 to 5.59 IU. As a result of the mass dog vaccination campaigns, human rabies cases due to dog-mediated rabies decreased from 60 in 1990 to 0 in 2000. The number of rabies cases in dogs decreased from 3,049 in 1990 to 70 cases last year.

  6. Origin of a basalt-to-trachyandesite/dacite suite in the Jemez volcanic field (New Mexico, USA) by upper crustal contamination

    NASA Astrophysics Data System (ADS)

    Baldridge, W. S.; Warren, R. G.

    2004-12-01

    Magmatic compositions in large, long-lived volcanic fields typically evolve through a variety of petrogenetic processes. Determining their relative roles may be difficult because (1) multiple processes may act simultaneously at a single volcano, (2) different processes may produce similar compositional results, and (3) individual processes may differ significantly at different volcanoes. To isolate the major processes and avoid the complex overprinting of multiple processes in the main Jemez volcanic field (JVF), we obtained whole-rock major- and trace-element compositions and mineral compositions from a small basalt-to-trachyandesite/dacite volcanic field (Cerros del Rio, CDR) adjacent to the main JVF. Lavas of the CDR field were erupted during development of the middle to upper crustal magma chamber (4-1 Ma) that resulted in formation of Toledo and Valles calderas at 1.6-1.2 Ma, but were not affected by mixing with the main chamber. The mafic end members of this suite typically range from basanite/alkali olivine basalt to hawaiite (SiO2 44-52%; Na2O+K2O 4.2-6.3%), likely derived from an ocean-island-basalt (OIB)-modified lithospheric source (McMillan, N. Mex. Geol. Soc. Guidebook 49, 107-116, 1998). Compositions range to trachyandesite and dacite (SiO2 65-67%; Na2O+K2O 6.9-7.2%) (classification of Le Bas et al., J. Petrol., 27, 745-750, 1986). Trace elements (e.g., Th, Zr) are not well correlated with major elements. Phenocrysts range from olivine and plagioclase in the least evolved lavas to high- and low-Ca pyroxene and sodic plagioclase in the intermediate to silicic members. Primitive members of this series contain gabbroic xenoliths and evolved members are typified by quartzofeldspathic xenoliths and by xenocrysts of quartz and feldspar, which we infer were derived from middle to upper crust. Using only whole-rock compositions observed in the CDR, we can model the major-element compositional range assuming removal of observed phenocryst phases coupled with

  7. Mexico and Central America.

    PubMed

    Bronfman, M

    1998-01-01

    This article reviews the literature on migration and HIV/AIDS in Mexico and Central America, including Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama. Most migrants travel to the US through Mexico. US-Mexico trade agreements created opportunities for increased risk of HIV transmission. The research literature focuses on Mexico. Most countries, with the exception of Belize and Costa Rica, are sending countries. Human rights of migrants are violated in transit and at destination. Migration policies determine migration processes. The Mexican-born population in the US is about 3% of US population and 8% of Mexico's population. About 22% arrived during 1992-97, and about 500,000 are naturalized US citizens. An additional 11 million have a Mexican ethnic background. Mexican migrants are usually economically active men who had jobs before leaving and were urban people who settled in California, Texas, Illinois, and Arizona. Most Mexican migrants enter illegally. Many return to Mexico. The main paths of HIV transmission are homosexual, heterosexual, and IV-drug-injecting persons. Latino migrants frequently use prostitutes, adopt new sexual practices including anal penetration among men, greater diversity of sexual partners, and use of injectable drugs.

  8. Field evaluation of two shallow land burial trench cap designs for long-term stabilization and closure of waste repositories at Los Alamos, New Mexico

    SciTech Connect

    Nyhan, J.; Drennon, B.; Hakonson, T.

    1989-02-01

    The results from several field experiments on methods to control soil erosion, biointrusion, and water infiltration were used to design and test a burial site cover which improves the ability of the disposal site to isolate the wastes. The performance of the improved cover design in managing water and biota at the disposal site was compared with a more conventional design widely used in the industry. The conventional trench cover design consists of 15 cm of sandy loam topsoil over 75 cm of sandy silt backfill, whereas the improved trench cover design consists of 75 cm of topsoil over a minimum of 25 cm of gravel and 90 cm of river cobble. Each plot was lined with an impermeable liner to allow for mass balance calculation of water dynamics and contains hydrologic tracer ions (iodide and bromide) to demonstrate movement of water through the various zones of the trench cap. Cesium was emplaced beneath the trench cap to indicate root penetration through the trench cap, observed by sampling plant samples collected on the plots and assaying them for cesium. The field data are summarized and discussed in terms of its usefulness for waste management decisions. 67 refs., 44 figs., 4 tabs.

  9. Geochemistry of intrusive rocks associated with the Latir volcanic field, New Mexico, and contrasts between evolution of plutonic and volcanic rocks

    USGS Publications Warehouse

    Johnson, C.M.; Czamanske, G.K.; Lipman, P.W.

    1989-01-01

    Plutonic rocks associated with the Latir volcanic field comprise three groups: 1) ???25 Ma high-level resurgent plutons composed of monzogranite and silicic metaluminous and peralkaline granite, 2) 23-25 Ma syenogranite, and alkali-feldspar granite intrusions emplaced along the southern caldera margin, and 3) 19-23 Ma granodiorite and granite plutons emplaced south of the caldera. Major-element compositions of both extrusive and intrusive suites in the Latir field are broadly similar; both suites include high-SiO2 rocks with low Ba and Sr, and high Rb, Nb, Th, and U contents. Moreover, both intermediateto siliciccomposition volcanic and plutonic rocks contain abundant accessory sphene and apatite, rich in rare-earth elements (REE), as well as phases in which REE's are essential components. Strong depletion in Y and REE contents, with increasing SiO2 content, in the plutonic rocks indicate a major role for accessory mineral fractionation that is not observed in volcanic rocks of equivalent composition. Considerations of the rheology of granitic magma suggest that accessory-mineral fractionation may occur primarily by filter-pressing evolved magmas from crystal-rich melts. More limited accessory-mineral crystallization and fractionation during evolution of the volcanic magmas may have resulted from markedly lower diffusivities of essential trace elements than major elements. Accessory-mineral fractionation probably becomes most significant at high crystallinities. The contrast in crystallization environments postulated for the extrusive and intrusive rocks may be common to other magmatic systems; the effects are particularly pronounced in highly evolved rocks of the Latir field. High-SiO2 peralkaline porphyry emplaced during resurgence of the Questa caldera represents non-erupted portions of the magma that produced the Amalia Tuff during caldera-forming eruption. The peralkaline porphyry continues compositional and mineralogical trends found in the tuff. Amphibole

  10. Partnership with Mexico

    DTIC Science & Technology

    2012-05-01

    NORAD and USNORTHCOM THEATER SECURITY COOPERATION (TSC) “PARTNERSHIP WITH  MEXICO ” This briefing is UNCLASSIFIED Report Documentation Page Form...COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Partnership with Mexico 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Mission: As directed by the Secretary of Defense,  USNORTHCOM conducts security cooperation  activities with The Bahamas, Canada, and  Mexico   to build

  11. Mexico: The Ultimate Domino?

    DTIC Science & Technology

    1988-05-01

    AIRa WARt COLLEIGE UMtI SBARCH RIEPORT 0 MEXICO : THE ULTIMATE DOMINO? 0q LT COL JOHN C. MANGELS � COSC 1988 RELECTE MjN VESIA 09 274, vrn’rW...STAT[ES AIR FORCE, RaAKLVi\\idIA AI FOCE BASE AL"AMA ~ A~E AIR IAAR COLLEGE AIR UNI’VERSIT( MEXICO : THE ULTIMATE DOMINO? b/ John C. Mangels... Mexico : The Ultimate Domino? AUTHOR: John C. Mangels, Lieutenant Colonel, USAF " Critical examination of Congressional testimony, and r onj-,:,r press

  12. 75 FR 439 - Notice of Invitation To Participate; Exploration for Coal in New Mexico; License NMNM 123298

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ....O. Box 27115, Santa Fe, New Mexico 87502-0115. Any parties electing to participate in this... State Office, P.O. Box 27115, Santa Fe, New Mexico 87502-0115 and the San Juan Coal Company, P.O. Box..., Santa Fe, New Mexico 87508, and the BLM's Farmington Field Office, 1235 La Plata Highway, Suite...

  13. Evidence of vertical transmission and co-circulation of chikungunya and dengue viruses in field populations of Aedes aegypti (L.) from Guerrero, Mexico.

    PubMed

    Dzul-Manzanilla, Felipe; Martínez, Norma E; Cruz-Nolasco, Maximina; Gutiérrez-Castro, Cipriano; López-Damián, Leonardo; Ibarra-López, Jesús; Martini-Jaimes, Andres; Bibiano-Marín, Wilbert; Tornez-Benitez, Citlalli; Vazquez-Prokopec, Gonzalo M; Manrique-Saide, Pablo

    2016-02-01

    We report results of the entomo-virological surveillance system in Aedes aegypti local populations performed by the Ministry of Health of Guerrero. Indoor-adult Ae. aegypti collected at Acapulco, Zihuatanejo, Coyuca de Benitez and Atoyac de Alvarez (dry season, 2015) were processed for dengue virus (DENV) and chikungunya virus (CHIKV) using RT-PCR. We identified different seroptypes of DENV (2, 3 and 4), CHIKV and their co-circulation in field-caught mosquitoes across a significant geographic area. Pools of males were positive for CHIKV and DENV 3 and 4 suggesting vertical transmission. Entomo-virological surveillance in Guerrero has identified early circulation of CHIKV and DENV and provided a trigger for timely and focalized vector control actions. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. 410 Epidemiological and Clinical Characteristics of Allergic Conjunctivitis Patients in a Reference Center of Mexico City

    PubMed Central

    Robles-Contreras, Atzin; Ayala-Balboa, Julio; Alonso-Sánchez, Miguel E.; Estrada-Garcia, Iris; Jiménez-Martínez, Maria C.

    2012-01-01

    Background In our country (Mexico) there are few reports about epidemiological characteristics of allergic conjunctivitis patients; despite these studies give us some information about patient profile, in most cases these studies are not always comparable due to the use of different methodologies, that is, Include only a portion of the population (elderly, infants) or there are limited to one region of the city. The purpose of this study was to know the epidemiological and clinical characteristics of allergic conjunctivitis (AC)-patients in the biggest reference center of ocular diseases in Mexico (Institute of Ophthalmology “Conde de Valenciana”) Methods Data were obtained from clinical records. Six hundred fifteen patients with diagnosis of AC were included. Epidemiological characteristics included sex, age, residence; clinical-immunological characteristics included atopy, coexistence of other allergies, total IgE, cutaneous reactivity to skin prick test (SPT), sixty allergens were evaluated. Descriptive statistics were performed to obtain frequencies and t test was used to find significant differences, P < 0.05 was considered statistically significant. Results AC-Patients who received medical consultation at the Institute of Ophthalmology where predominantly from State of Mexico (47.25%), Mexico City (37.5%), and in less frequency Hidalgo, Puebla, Tlaxcala, Michoacan, Veracruz, Oaxaca, Guerrero, Chiapas and Guanajuato. 88% of AC-patients were positive to SPT (SPT+), while 12% were negative to SPT (SPT-). Age of diagnosis was significant different between SPT-AC-patients and SPT+AC-patients (14.5-years vs 17.9-years, P = 0.02). Male SPT-AC-patients were diagnosed younger than male SPT+AC-patients (P = 0.001). IgE concentration was significant increased in male SPT+AC-patients than female SPT+AC-patients (P = 0.006). The most common skin reactivity was against Dermatophagoides sp (59.1%), Aedes sp(54.55%) and Blatella-Periplaneta sp.(31.14%); we did not

  15. Anaglyph, Yucatan Peninsula, Mexico

    NASA Image and Video Library

    2003-03-06

    This anaglyph of Mexico Yucatan Peninsula was generated from NASA Shuttle Radar Topography Mission data, and shows a subtle but distinctive indication of the Chicxulub impact crater. 3D glasses are necessary to view this image.

  16. Can pictorial warning labels on cigarette packages address smoking-related health disparities? Field experiments in Mexico to assess pictorial warning label content.

    PubMed

    Thrasher, James F; Arillo-Santillán, Edna; Villalobos, Victor; Pérez-Hernández, Rosaura; Hammond, David; Carter, Jarvis; Sebrié, Ernesto; Sansores, Raul; Regalado-Piñeda, Justino

    2012-03-01

    The objective of this study was to determine the most effective content of pictorial health warning labels (HWLs) and whether educational attainment moderates these effects. Field experiments were conducted with 529 adult smokers and 530 young adults (258 nonsmokers; 271 smokers). Participants reported responses to different pictorial HWLs printed on cigarette packages. One experiment involved manipulating textual form (testimonial narrative vs. didactic) and the other involved manipulating image type (diseased organs vs. human suffering). Tests of mean ratings and rankings indicated that pictorial HWLs with didactic textual forms had equivalent or significantly higher credibility, relevance, and impact than pictorial HWLs with testimonial forms. Results from mixed-effects models confirmed these results. However, responses differed by participant educational attainment: didactic forms were consistently rated higher than testimonials among participants with higher education, whereas the difference between didactic and testimonial narrative forms was weaker or not statistically significant among participants with lower education. In the second experiment, with textual content held constant, greater credibility, relevance, and impact was found for graphic imagery of diseased organs than imagery of human suffering. Pictorial HWLs with didactic textual forms seem to work better than those with testimonial narratives. Future research should determine which pictorial HWL content has the greatest real-world impact among consumers from disadvantaged groups, including assessment of how HWL content should change to maintain its impact as tobacco control environments strengthen and consumer awareness of smoking-related risks increases.

  17. The questa magmatic system: Petrologic, chemical and isotopic variations in cogenetic volcanic and plutonic rocks of the latir volcanic field and associated intrusives, northern New Mexico

    SciTech Connect

    Johnson, C.M.

    1986-01-01

    Field, chemical and isotopic data demonstrate that nearly all igneous rocks at Questa resulted from interactions between mantle-derived parental magmas and the crust. Strontium, neodymium and lead isotope ratios of early andesites to rhyolites (28 to 26 Ma) indicate that these magmas assimilated > 25% lower crust. Injection of basaltic magmas extensively modified the strontium and neodymium but not the lead isotope compositions of the lower crust. Eruption of comendite magmas and the peralkaline Amalia Tuff 26 Ma is correlated with inception of regional extension. Lead isotope ratios identify different sources for the metaluminous granites and the peralkaline rocks. 26 Ma metaluminous granite to granodiorite intrusions have chemical and isotopic compositions to those of the precaldera intermediate-composition rocks, and are interpreted as representing the solidified equivalents of the precaldera magmatic episode. However, both conventional and ion-microprobe isotopic data prohibit significant assimilation of crustal rocks at the level of exposure, suggesting that the plutons were emplaced a relatively crystal-rich mushes which did not have sufficient heat to assimilate country rocks. This suggest that in some cases plutonic rocks are better than volcanic rocks in representing the isotopic compositions of their source regions, because the assimilation potential of crystal-rich magmas is significantly less than that of largely liquid magmas.

  18. Can pictorial warning labels on cigarette packages address smoking-related health disparities?: Field experiments in Mexico to assess warning label content

    PubMed Central

    Thrasher, James F.; Arillo-Santillán, Edna; Villalobos, Victor; Pérez-Hernández, Rosaura; Hammond, David; Carter, Jarvis; Sebrié, Ernesto; Sansores, Raul; Regalado-Piñeda, Justino

    2012-01-01

    Objective This study aimed to determine the most effective content of pictorial health warning labels (HWLs) and whether educational attainment moderates these effects. Methods Field experiments were conducted with 529 adult smokers and 530 young adults (258 nonsmokers; 271 smokers), wherein participants reported responses to different HWLs printed on cigarette packages. One experiment involved manipulating textual form (testimonial narrative vs didactic) and the other involved manipulating imagery type (diseased organs vs human suffering). Results Tests of mean ratings and rankings indicated that HWLs with didactic textual forms had equivalent or significantly higher credibility, relevance, and impact than HWLs with testimonial forms. Results from mixed-effects models confirmed these results. However, responses differed by participant educational attainment: didactic forms were consistently rated higher than testimonials among participants with higher education, whereas the difference between didactic and testimonial narrative forms was weaker or not statistically significant among participants with lower education. In the second experiment, with textual content held constant, greater credibility, relevance and impact was found for graphic imagery of diseased organs than imagery of human suffering. Conclusions Pictorial HWLs with didactic textual forms appear to work better than with testimonial narratives. Future research should determine which pictorial HWL content has the greatest real-world impact among consumers from disadvantaged groups, including assessment of how HWL content should change to maintain its impact as tobacco control environments strengthen and consumer awareness of smoking-related risks increases. PMID:22350859

  19. Forests of Mexico

    SciTech Connect

    Cairns, M.A.; Dirzo, R.; Zadroga, F.

    1995-07-01

    Forest of Mexico as elsewhere provide essential goods and services for both local citizens and the international community. Benefits include climate regulation, biodiversity, and wood and nonwood products for local consumption and economic activity. Deforestation is a matter of great environmental and economic concern. This article assesses rates of deforestation, the present status of forest in Mexico, and the major factors responsible for deforestation in the tropical southeastern region.

  20. Mexico: Paving the way

    SciTech Connect

    Erckert, C.

    1993-02-01

    The North American Free Trade Agreement (NAFTA) signed last year by the presidents of Mexico and the United States and the Canadian prime minister will pave the way for increased outside participation in Mexico's growing energy sector. In its penultimate session of 1992, the Mexican Congress approved a bill which would enact the treaty provisions into domestic law and expand upon the details of previously enacted liberalization plans.

  1. Preliminary Geochemical and Petrologic Assessment of the Fanney Rhyolite and the Bloodgood Canyon and Apache Springs tuffs, Mogollon-Datil Volcanic Field, New Mexico

    NASA Astrophysics Data System (ADS)

    Salings, E. E.; Rentz, S. P.; Michelfelder, G.; Sikes, E. R.

    2015-12-01

    Continental arc volcanoes represent a dramatic expression of a significant and fundamental phenomena in global tectonics: the subduction of an oceanic plate beneath a more buoyant continental plate. The subduction of an oceanic plate results in recycling of crustal material into the convecting mantle, partial melting, and primary basalt production. Moreover, during passage through thick continental crust, subduction zone magmas may substantially differentiate and melt crustal rocks giving rise to the great diversity of igneous lithologies characteristic of earth. These are important processes that must be understood in detail in order to interpret the long-term evolution of the earth and continental crust. Here we present variations in the isotopic and trace element composition of volcanic rocks from Bloodgood Canyon and Apache Springs tuffs, and the Fanney Rhyolite located in the western Mogollon-Datil Volcanic Field (MDVF). The project will address several questions. First, are the Bloodgood and Apache Springs tuffs and Fanney Rhyolite petrogenically related, and are these rhyolites expressions of a continental arc ignimbrite flare-up? Second, what petrogenic processes affected differentiation and where is the magma sourced? Finally, to what extent do these units represent a manifestation of the MDVF and the transition from arc magmatism to rifting? The Bloodgood Canyon is a crystal-rich rhyolite tuff containing quartz>k-feldspar>plagioclase>biotite, and pumice and lithic fragments. Rb ranges from 230-330ppm, Sr from 14-83ppm, and 87Sr/86Srm from 0.71619-0.72477.The Apache Springs Tuff is a rhyolite tuff containing quartz>k-feldspar>plagioclase>biotite, and lithics. Rb (228-233ppm) and 87Sr/86Srm (0.71025-0.71056) are restricted, while Sr (105-399ppm) is more variable in composition. The Fanney Creek is a massive rhyolite lava with flow banding and contains quartz phenocryst clusters and k-feldspars. Currently, no data exists for the Apache Springs Tuff.

  2. Brief Lifespans and Rapid Recurrence of Large Ignimbrite-Caldera Cycles (Super-Eruptions) in the Mid-Tertiary Southern Rocky Mountain Volcanic Field, Colorado-New Mexico

    NASA Astrophysics Data System (ADS)

    Lipman, P. W.; McIntosh, W. C.; Zimmerer, M. J.

    2010-12-01

    Recent geologic mapping, high-precision single-crystal sanidine 40Ar-39Ar ages, and petrologic data for eruptive products from the Southern Rocky Mountain Volcanic Field (SRMVF, 37-23 Ma) demonstrate that many individual ignimbrite caldera cycles, including precursor activity and post-caldera lavas and intrusions, were completed in notably brief time intervals, many less than 50,000-100,000 years. The ~30 high-K calc-alkaline ignimbrite sheets of the mid-Tertiary SRMVF, with individual volumes of 100-5,000 km3, are compositionally typical of eastern Cordilleran magmatism the length of the Western Hemisphere. Large compositional variations, both within single zoned ignimbrite sheets (typically crystal-poor rhyolite to crystal-rich dacite), and between the ignimbrites and diverse andesite-dacite lava fills in source calderas, demonstrate rapidly evolving petrologic processes in source magmas. Recurrence intervals between successive ignimbrite eruptions, both from individual polycyclic caldera complexes and from geographically adjacent caldera centers, vary randomly--from intervals too brief to resolve with best available geochronologic methods (about 50,000 years for mid-Tertiary sanidine), to repose intervals of several million years. Ignimbrite-caldera repose intervals in the SRMVF were longest at inception of regional eruptive activity, at termination, and during a major shift in the geographic locus of activity. The shortest repose intervals are notably more brief than better known examples of supererption recurrence such as the three Pleistocene ignimbrites from the Yellowstone area at 2.1, 1.3, and 0.64 Ma, indicating that large-volume caldera-forming ignimbrite eruptions and associated precursor and successor lavas can be more frequent future volcanic hazards than previously appreciated.

  3. Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Herndon, S. C.; Slott, R. S.; Dunlea, E. J.; Marr, L. C.; Shorter, J. H.; Zahniser, M.; Knighton, W. B.; Rogers, T. M.; Kolb, C. E.; Molina, L. T.; Molina, M. J.

    2006-11-01

    A mobile laboratory was used to measure on-road vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NOx and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NOx, NOy, NH3, H2CO, CH3CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles in the form of frequency distributions as well as estimates for the fleet averaged emissions. Our measurements of emission ratios for both CNG and gasoline powered "colectivos" (public transportation buses that are intensively used in the MCMA) indicate that - in a mole per mole basis - have significantly larger NOx and aldehydes emissions ratios as compared to other sampled vehicles in the MCMA. Similarly, ratios of selected VOCs and NOy showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in U.S. cities. We estimate NOx emissions as 100 600±29 200 metric tons per year for light duty gasoline vehicles in the MCMA for 2003. According to these results, annual NOx emissions estimated in the emissions inventory for this category are within the range of our estimated NOx annual emissions. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

  4. Mexico's Luna discoveries are more than moonshine

    SciTech Connect

    Stewart-Gordon, T.J.; Baker, G.T.

    1987-05-01

    Just when it seemed that Mexico's petroleum reserves may have been overstated, the state oil company opened a new province. Petroleos Mexicanos (Pemex) geologists think the Luna area of Tabasco State and the Gulf of Mexico could add the condensate and gas equivalent of 20 billion bbl of light oil to Mexico's proven reserves. If true, this would be the largest discovery in Mexico since the Campeche Sound fields in 1976. To date, the new province stretches about 50 miles between the Caribbean coastal towns of Frontera and Puerto Ceiba in Tabasco State, and extends some 31 miles offshore (see map). Since the early 1970s, Pemex geologists have postulated that the entire Yucatan platform will prove productive. Luna finds reduce the distance between Campeche fields and onshore production to 93 miles. The Luna area is ideally suited for rapid development - it is about 40 miles northeast of Villahermosa, Tabasco, and within 60 miles of the export terminal at Dos Bocas near the border between Tabasco and Vera Cruz states. It is also less than 50 miles from the Cactus gas-processing and petrochemical plants in Chiapas State, which means that gas can be put into the country's trunk line that extends to the U.S. grid at Reynosa.

  5. Developing a platform for genomic medicine in Mexico.

    PubMed

    Jimenez-Sanchez, Gerardo

    2003-04-11

    Mexico is preparing to develop a genomic medicine program focused on national health problems. Modern Mexicans result from an admixture of more than 65 native Indian groups with Spaniards, leading to a unique genetic makeup and a characteristic set of disease susceptibilities. Since 1999, more than 100 experts from different fields have joined efforts with government, academia, and industry to identify priorities and goals for genomic medicine in Mexico. The plan includes establishment of an Institute of Genomic Medicine with strong intramural and extramural programs. This project is expected to ease the social and financial burden of health problems in Mexico.

  6. An evaluation of aquifer and well characteristics of municipal well fields in Los Alamos and Guaje Canyons, near Los Alamos, New Mexico

    USGS Publications Warehouse

    Cushman, Robert L.

    1965-01-01

    The Jenkins-Whitesburg area includes approximately 250 square miles In Letcher and Pike Counties in the southeastern part of the Eastern Coal Field. In this area ground water is the principal source of water for nearly all rural families, most public supplies, several coal mines and coal processing plants, and one bottling plant. The major aquifers in the Jenkins-Whitesburg area are the Breathitt and Lee Formations of Pennsylvanian age. Other aquifers range in age from Devonian to Quaternary but are not important in this area because they occur at great depth or yield little or no water. The Breathitt Formation occurs throughout the area except along the crest and slopes of Pine Mountain and where it is covered by unconsolidated material of Quaternary age. The Breathitt Formation consists of shale, sandstone, and lesser amounts of coal and associated underclay. The yield of wells penetrating the Breathitt Formation ranges from less than 1 to 330 gallons per minute. Well yield is controlled by the type and depth of well, character of the aquifer, and topography of the well site. Generally, deep wells drilled in valleys of perennial streams offer the best potential for high yields. Although enough water for a minimum domestic supply (more than 100 gallons per day) may be obtained from shale, all high-yielding wells probably obtain water from vertical joints and from bedding planes which are best developed in sandstone. About 13 percent of the wells inventoried in the Breathitt Formation failed to supply enough water for a minimum domestic supply. Most of these are shallow dug wells or drilled wells on hillsides or hilltops. Abandoned coal dunes are utilized as large infiltration galleries and furnish part of the water for several public supplies. The chemical quality of water from the Breathitt Formation varies considerably from place to place, but the water generally is acceptable for most domestic and industrial uses. Most water is a calcium magnesium bicarbonate

  7. Mouth of the Colorado River, Gulf of California, Mexico

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The rugged peninsula and eastern coastal plain of northern Baja California are separated from the rest of Mexico by the Gulf of California (32.0N, 115.0W) where the Colorado River is building a delta. Most of the surface features seen here, including the sinuous salt bottomed tidal channel on the delta, have remained unchanged since the first orbital photos in 1961. Irrigated agricultural fields can be seen along the U. S. and Mexico border.

  8. H, O, Sr, Nd, and Pb isotope geochemistry of the Latir volcanic field and cogenetic intrusions, New Mexico, and relations between evolution of a continental magmatic center and modifications of the lithosphere

    USGS Publications Warehouse

    Johnson, C.M.; Lipman, P.W.; Czamanske, G.K.

    1990-01-01

    Over 200 H, O, Sr, Nd, and Pb isotope analyses, in addition to geologic and petrologic constraints, document the magmatic evolution of the 28.5-19 Ma Latir volcanic field and associated intrusive rocks, which includes multiple stages of crustal assimilation, magma mixing, protracted crystallization, and open- and closed-system evolution in the upper crust. In contrast to data from younger volcanic centers in northern New Mexico, relatively low and restricted primary ??18O values (+6.4 to +7.4) rule out assimilation of supracrustal rocks enriched in 18O. Initial 87Sr/86Sr ratios (0.705 to 0.708), ??18O values (-2 to-7), and 206Pb/204Pb ratios (17.5 to 18.4) of metaluminous precaldera volcanic rocks and postcaldera plutonic rocks suggest that most Latir rocks were generated by fractional crystallization of substantial volumes of mantle-derived basaltic magma that had near-chondritic Nd isotope ratios, accompanied by assimilation of crustal material in two main stages: 1) assimilation of non-radiogenic lower crust, followed by 2) assimilation of middle and upper crust by inter-mediate-composition magmas that had been contaminated during the first stage. Magmatic evolution in the upper crust peaked with eruption of the peralkaline Amalia Tuff (???26 Ma), which evolved from metaluminous parental magmas. A third stage of late, roofward assimilation of Proterozoic rocks in the Amalia Tuff magma is indicated by trends in initial 87Sr/86Sr and 206Pb/204Pb ratios from 0.7057 to 0.7098 and 19.5 to 18.8, respectively, toward the top of the pre-eruptive magma chamber. Highly evolved postcaldera plutons are generally fine grained and are zoned in initial 87Sr/86Sr and 206Pb/204Pb ratios, varying from 0.705 to 0.709 and 17.8 to 18.6, respectively. In contrast, the coarser-grained Cabresto Lake (???25 Ma) and Rio Hondo (???21 Ma) plutons have relatively homogeneous initial 87Sr/86Sr and 206Pb/204Pb ratios of approximately 0.7053 and 17.94 and 17.55, respectively. ??18O values for

  9. Efficacy and safety of a patch vaccine containing heat-labile toxin from Escherichia coli against travellers' diarrhoea: a phase 3, randomised, double-blind, placebo-controlled field trial in travellers from Europe to Mexico and Guatemala.

    PubMed

    Behrens, Ronald H; Cramer, Jakob P; Jelinek, Tomas; Shaw, Hilary; von Sonnenburg, Frank; Wilbraham, Darren; Weinke, Thomas; Bell, David J; Asturias, Edwin; Pauwells, Hermann L Enkerlin; Maxwell, Roberto; Paredes-Paredes, Mercedes; Glenn, Gregory M; Dewasthaly, Shailesh; Stablein, Donald M; Jiang, Zhi-Dong; DuPont, Herbert L

    2014-03-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of travellers' diarrhoea. We investigated the efficacy and safety of a skin-patch vaccine containing the pathogen's heat-labile toxin (LT) in a population of travellers to Mexico and Guatemala. In this phase 3, randomised, double-blind, placebo-controlled field trial, healthy adults (aged 18-64 years) travelling from Germany or the UK to Mexico or Guatemala were assigned in a 1:1 ratio by a dynamic electronic randomisation system to receive transcutaneous immunisation with a patch containing 37.5 μg of ETEC LT or a placebo patch. Participants, site staff, and the investigators who did the analyses were masked to group assignment. Participants were vaccinated before travel, with two patches given 14 days apart. In the destination country, participants tracked stool output in a diary and provided stool samples for pathogen identification if diarrhoea occurred. The primary endpoint was the proportion of participants with at least one episode of moderate-to-severe diarrhoea (defined as four or more unformed stools in a 24 h period) in which either or both ETEC enterotoxins (LT and heat-stable toxin [ST]) were detected. The study is registered at ClinicalTrials.gov, number NCT00993681. 2036 participants were recruited and randomly assigned between Oct 14, 2009, and Aug 13, 2010, with 1016 allocated to receive the LT patch and 1020 the placebo patch. 821 participants in the LT-patch group and 823 in the placebo group received both vaccinations and were analysed in the per-protocol population. 30 (3.7%, 95% CI 2.5-5.2) participants in the LT-patch group and 46 (5.6%, 4.1-7.4) in the placebo group had moderate or severe ETEC diarrhoea (vaccine efficacy 34.6%, -2.2 to 58.9; p=0.0621). 9333 local (ie, patch-site) adverse events (including erythema, rash, pruritus, hyperpigmentation, pain, hypopigmentation, and oedema) occurred in 943 (93%) of 1015 participants in the LT-patch group, compared with 1444 local adverse

  10. Living Longer in Mexico

    PubMed Central

    Aguila, Emma; Diaz, Claudia; Fu, Mary Manqing; Kapteyn, Arie; Pierson, Ashley

    2012-01-01

    Abstract This analysis of aging and income security in Mexico establishes that the older population in Mexico is increasing quickly and that this population is especially vulnerable to poverty. Mexican citizens are living longer and overall have experienced an improvement in the quality of life compared to that of prior generations. However, this study demonstrates that social improvements are not affecting the daily lives of all persons equally. The authors attempt to uncover and highlight those differences. One of the primary challenges facing Mexico is a growing older population. The demographic transition in Mexico combined with the lack of formal sources of income in retirement place many older persons in a state of financial insecurity. The information contained in this study and the proposed policy research areas are intended to enlarge the portfolio of options for older Mexicans. The authors analyze wealth and sources of income during retirement, the relationship between health and wealth, urban and rural disparities, and the impact of migration spells to the United States on wealth accumulation and health insurance in Mexico. PMID:28083208

  11. Magnetic resonance imaging in Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez, A. O.; Rojas, R.; Barrios, F. A.

    2001-10-01

    MR imaging has experienced an important growth worldwide and in particular in the USA and Japan. This imaging technique has also shown an important rise in the number of MR imagers in Mexico. However, the development of MRI has followed a typical way of Latin American countries, which is very different from the path shown in the industrialised countries. Despite the fact that Mexico was one the very first countries to install and operate MR imagers in the world, it still lacks of qualified clinical and technical personnel. Since the first MR scanner started to operate, the number of units has grown at a moderate space that now sums up approximately 60 system installed nationwide. Nevertheless, there are no official records of the number of MR units operating, physicians and technicians involved in this imaging modality. The MRI market is dominated by two important companies: General Electric (approximately 51%) and Siemens (approximately 17.5%), the rest is shared by other five companies. According to the field intensity, medium-field systems (0.5 Tesla) represent 60% while a further 35% are 1.0 T or higher. Almost all of these units are in private hospitals and clinics: there is no high-field MR imagers in any public hospital. Because the political changes in the country, a new public plan for health care is still in the process and will be published soon this year. This plan will be determined by the new Congress. North American Free Trade Agreement (NAFTA) and president Fox. Experience acquired in the past shows that the demand for qualified professionals will grow in the new future. Therefore, systematic training of clinical and technical professionals will be in high demand to meet the needs of this technique. The National University (UNAM) and the Metropolitan University (UAM-Iztapalapa) are collaborating with diverse clinical groups in private facilities to create a systematic training program and carry out research and development in MRI

  12. Spatio-temporal evolution of anthropogenic deformation around Cerro Prieto geothermal field in the Mexicali Valley, B.C., Mexico, between 1993 and 2009 from DInSAR and leveling.

    NASA Astrophysics Data System (ADS)

    Sarychikhina, Olga; Glowacka, Ewa; Robles, Braulio; Mojarro, Jose

    2014-05-01

    Land subsidence is an environmental hazard which could be caused by withdrawal of large amounts of fluid from beneath the earth's surface. Land subsidence is an issue in several geothermal fields worldwide (e.g., Geysers, USA (Mossop and Segall, 1997), Wairakei-Tauhara, New Zealand (Allis et al., 2009)). Cerro Prieto geothermal field (CPGF), located in the Mexicali Valley, northwest Mexico, is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field (e.g. Glowacka et al., 1996, 1999; Carnec and Fabriol, 1999; Sarychikhina et al., 2011). The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. Detection of land subsidence and monitoring of the spatial and temporal changes of its pattern and magnitude can provide important information about the dynamics of this process and controlling geological structures. The technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) has been demonstrated to be a very effective technique for measuring ground deformation. This study presents an application of DInSAR interferogram stacking technique to investigate the land subsidence in the Mexicali Valley near CPGF. C-band ENVISAR ASAR images acquired between 2003 and 2009 from the ascending (track 306, frame 639) and descending track (track 84, frame 2961), obtained from the European Space Agency (ESA), as part of ESA CAT-1 project (ID - C1P3508), were used. Gamma ISP and DIFF/GEO software packages were used to calculate differential interferograms from SLC data and for differential interferograms stacking (Wegmüller and Werner, 1997). Eight average annual deformation rate maps were generated for 2005 (descending

  13. New Mexico and Cultural Pluralism.

    ERIC Educational Resources Information Center

    Lopez, Thomas R., Jr.

    In this paper, the cultural pluralism which exists in New Mexico is discussed. Most citizens of New Mexico have been placed in 1 of 3 categories: Indians, Anglo-Americans, and Spanish Americans. Since Spanish and English are the official languages of New Mexico, making it the only officially bilingual state, the Spanish American culture is…

  14. Renewable energy systems in Mexico: Installation of a hybrid system

    NASA Astrophysics Data System (ADS)

    Pate, Ronald C.

    1993-05-01

    Sandia has been providing technical leadership on behalf of DOE and CORECT on a working level cooperative program with Mexico on renewable energy (PROCER). As part of this effort, the Sandia Design Assistance Center (DAC) and the solar energy program staff at Instituto de Investigaciones Electricas (IIE) in Cuernavaca, Mexico, recently reached agreement on a framework for mutually beneficial technical collaboration on the monitoring and field evaluation of renewable energy systems in Mexico, particularly village-scale hybrid systems. This trip was made for the purpose of planning the details for the joint installation of a data acquisition system (DAS) on a recently completed PV/Wind/Diesel hybrid system in the village of Xcalac on the Southeast coast of the state of Quintana Roo, Mexico. The DAS installation will be made during the week of March 15, 1993. While in Mexico, discussions were also held with personnel from.the National Autonomous University of Mexico (UNAM) Solar Energy Laboratory and several private sector companies with regard to renewable energy project activities and technical and educational support needs in Mexico.

  15. NASA Gulf of Mexico Initiative Hypoxia Research

    NASA Technical Reports Server (NTRS)

    Armstrong, Curtis D.

    2012-01-01

    The Applied Science & Technology Project Office at Stennis Space Center (SSC) manages NASA's Gulf of Mexico Initiative (GOMI). Addressing short-term crises and long-term issues, GOMI participants seek to understand the environment using remote sensing, in-situ observations, laboratory analyses, field observations and computational models. New capabilities are transferred to end-users to help them make informed decisions. Some GOMI activities of interest to the hypoxia research community are highlighted.

  16. OCEANOGRAPHY OF THE GULF OF MEXICO.

    DTIC Science & Technology

    Gulf of Mexico which has been carried on during the past year. Included are reviews of work in physical oceanography, geophysics, geology, geo-chemistry, chemistry, instrumentation, and biofouling. Attention is called to the fact that several special reports have been issued by individual investigators that discuss specific research activities in greater detail. The field work carried out aboard the R/V ALAMINOS is summarized, and publications, papers, and reports resulting from the work are presented.

  17. Chiapas Forest, Mexico and Guatemala border

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This color infrared view of the Chiapas Forest, Mexico and Guatemala border (17.0N, 92.0W) illustrates the usefulness of this type of film in determining vegetated vs non vegetated areas. As can be seen, most of this part of Guatemala remains in closed canopy woodland (dark red), while most of the Mexican land to the north has been cleared for pasture and farmland (pink). The pale green areas north of the river are bare soil or fallow fields.

  18. Counternetwork: Countering the Expansion of Transnational Criminal Networks

    DTIC Science & Technology

    2017-01-01

    the Aryan Brotherhood, the New Mexico Syndicate, Nuestra Familia , the Northern Structure, the Black Guerrilla Family, Mexikanemi, Barrio Azteca, the...BLO), Los Zetas Sinaloa Federation La Familia Michoacaná Michoacaná State Cabelleros Templarios (aka Knights Templar) Cabelleros Templarios (aka...Knights Templar) Michoacaná State La Familia Micoacaná Jalisco Cartel New Generation (CJNG) Southern stretches of Mexico’s Pacific coats; parts

  19. Semi-automatic delimitation of volcanic edifice boundaries: Validation and application to the cinder cones of the Tancitaro-Nueva Italia region (Michoacán-Guanajuato Volcanic Field, Mexico)

    NASA Astrophysics Data System (ADS)

    Di Traglia, Federico; Morelli, Stefano; Casagli, Nicola; Garduño Monroy, Victor Hugo

    2014-08-01

    The shape and size of monogenetic volcanoes are the result of complex evolutions involving the interaction of eruptive activity, structural setting and degradational processes. Morphological studies of cinder cones aim to evaluate volcanic hazard on the Earth and to decipher the origins of various structures on extraterrestrial planets. Efforts have been dedicated so far to the characterization of the cinder cone morphology in a systematic and comparable manner. However, manual delimitation is time-consuming and influenced by the user subjectivity but, on the other hand, automatic boundary delimitation of volcanic terrains can be affected by irregular topography. In this work, the semi-automatic delimitation of volcanic edifice boundaries proposed by Grosse et al. (2009) for stratovolcanoes was tested for the first time over monogenetic cinder cones. The method, based on the integration of the DEM-derived slope and curvature maps, is applied here to the Tancitaro-Nueva Italia region of the Michoacán-Guanajuato Volcanic Field (Mexico), where 309 Plio-Quaternary cinder cones are located. The semiautomatic extraction allowed identification of 137 of the 309 cinder cones of the Tancitaro-Nueva Italia region, recognized by means of the manual extraction. This value corresponds to the 44.3% of the total number of cinder cones. Analysis on vent alignments allowed us to identify NE-SW vent alignments and cone elongations, consistent with a NE-SW σmax and a NW-SE σmin. Constructing a vent intensity map, based on computing the number of vents within a radius r centred on each vent of the data set and choosing r = 5 km, four vent intensity maxima were derived: one is positioned in the NW with respect to the Volcano Tancitaro, one in the NE, one to the S and another vent cluster located at the SE boundary of the studied area. The spacing of centroid of each cluster (24 km) can be related to the thickness of the crust (9-10 km) overlying the magma reservoir.

  20. Avian influenza in Mexico.

    PubMed

    Villarreal, C

    2009-04-01

    The outbreak of highly pathogenic avian influenza (HPAI) H5N2 in Mexico in 1994 led to a clear increase in biosecurity measures and improvement of intensive poultry production systems. The control and eradication measures implemented were based on active surveillance, disease detection, depopulation of infected farms and prevention of possible contacts (identified by epidemiological investigations), improvement of biosecurity measures, and restriction of the movement of live birds, poultry products, by-products and infected material. In addition, Mexico introduced a massive vaccination programme, which resulted in the eradication of HPAI in a relatively short time in two affected areas that had a high density of commercial poultry.

  1. [Dermatophytoses in Mexico].

    PubMed

    Arenas, Roberto

    2002-06-01

    The dermatophytic infections are superficial mycoses common in Mexico, they have an estimated frequency of 5% in dermatological outpatients. In this review we present a global view of these mycoses as well as their etiological agents in tinea capitis, tinea pedis, tinea corporis, tinea cruris and onychomycosis and also uncommon infections such as tinea imbricata and epidermophytosis of the diaper area. We also analyze these infections in diabetic patients, healthy carriers and dermatophytic infections in pets and laboratory animals. The most important publications about dermatophytosis in Mexico in the dermatological, epidemiological or mycological area are reviewed, specially those published in the last ten years.

  2. Mexico's first domestic satellite

    NASA Astrophysics Data System (ADS)

    Sanchez-Ruiz, M. E.; Elbert, B. R.

    The principal features of the Morelos communications satellite program, providing Mexico with C-band and Ku-band TV and telephone services beginning in 1985, are reviewed. Two satellites, modified versions of the Hughes HS-376 dual-spin bus, will be launched by STS and controlled from a tracking, telemetery, and command station near Mexico City; the 184-station ground network currently operating with Intelsat-IV will be expanded to about 1000 C-band stations (plus numerous small Ku-band receivers) by 1990. The spacecraft design, communications-subsystem performance, repeater equipment, antennas, and coverage pattern are presented in tables, drawings, diagrams, photographs and maps and discussed.

  3. Teledermatology in Tijuana, Mexico.

    PubMed

    Brown, Megan

    2016-12-01

    The Health Frontiers in Tijuana (HFiT) clinic is a binational partnership between the University of California, San Diego School of Medicine (San Diego, California); the Universidad Autónoma de Baja California School of Medicine (Tijuana, Mexico); and Desayunador Salesiano Padre Chava, a community grassroots organization in Tijuana, Mexico. Health Frontiers in Tijuana provides accessible quality health care for the underserved in Tijuana's Zona Norte. This article is a narrative meant to share my clinical experience as a dermatology resident who worked with HFiT to establish teledermatology services at this clinic.

  4. Biological studies and field observations in Europe of Lasioptera donacis potential biological control agent of giant reed, Arundo donax, an invasive weed of the Rio Grande Basin of Texas and Mexico

    USDA-ARS?s Scientific Manuscript database

    Giant reed, Arundo donax L. (Poaceae; Arundinoideae), is a clonal reed grass that is native from the western Mediterranean to India and invasive in North America and other arid temperate/subtropical parts of the world, including the Rio Grande Basin of Texas and Mexico. A biological control of gian...

  5. Paleoecological studies at Lake Patzcuaro on the west-central Mexican Plateau and at Chalco in the basin of Mexico

    USGS Publications Warehouse

    Watts, W.A.; Bradbury, J.P.

    1982-01-01

    A 1520-cm sediment core from Lake Patzcuaro, Michoacan, Mexico, is 44,000 yr old at the base. All parts of the core have abundant pollen of Pinus (pine), Alnus (alder), and Quercus (oak) with frequent Abies (fir). The interval dated from 44,000 to 11,000 yr ago has a homogeneous flora characterized by abundant Juniperus (juniper) pollen and frequent Artemisia (sagebrush). It is believed to represent an appreciably drier and colder climate than at present. The Holocene at Lake Patzcuaro is characterized by a moderate increase in Pinus pollen and the loss of Juniperus pollen, as the modern type of climate succeeded. Alnus was abundant until about 5000 yr ago; its abrupt decrease with the first appearance of herbaceous weed pollen may reflect the cutting of lake-shore and stream-course alder communities for agricultural purposes, or it may simply reflect a drying tendency in the climate. Pollen of Zea (corn) appears at Lake Patzcuaro along with low peaks of chenopod and grass pollen at 3500 yr B.P. apparently recording a human population large enough to modify the natural environment, as well as the beginning of agriculture. A rich aquatic flora in this phase suggests eutrophication of the lake by slope erosion. In the most recent period corn is absent from the sediments, perhaps reflecting a change in agricultural practices. The environment changes at Lake Patzcuaro are similar to and correlate with those in the Cuenca de Mexico, where diatom stratigraphy from the Chalco basin indicates fluctuations in lake levels and lake chemistry in response to variations in available moisture. Before 10,000 yr ago climates there were cool and dry, and the Chalco basin was occupied by a shallow freshwater marsh that drained north to Lake Texcoco, where saline water accumulated by evaporation. Increases in effective moisture and possible melting of glaciers during the Holocene caused lake levels to rise throughout the Cuenca de Mexico, and Lake Texcoco flooded the Chalco basin with

  6. Southern Mexico Miocene Magmatic Activity

    NASA Astrophysics Data System (ADS)

    Layer, P.

    2006-12-01

    Magmatic activity in southern Mexico have been occurred in three important volcanic regions: Los Tuxtlas Volcanic Field (TVF), Chiapanecan Volcanic Arc (CVA), and Tacaná Volcanic Complex (TVC). This activity produce alkaline and calc-alkaline products. The TVF has been active since 7 Ma ago producing Na-alkaline basanite, trachybasalt, and trachyandesite (41 63 wt% SiO2), and calc-alkaline basalts, basaltic-andesites, and andesites (45 63 wt% SiO2). The CVA including El Chichon Volcano produced calc-alkaline magmas varying from andesites to dacites (57 65 wt% SiO2) emitted between 2100 ka ago (Tzontehuitz) to 225 ka and K-alkaline magmas emitted from 1.1 Ma ago (trachybasalt, 46 51 wt% SiO2) to the Recent (trachyandesite, 57 63 wt% SiO2). The TVC emitted calc-alkaline products varying from basaltic-andesite (52 57 wt% SiO2) as mafic enclaves, andesites (57 63 wt% SiO2), and dacites (63 68 wt% SiO2). El Chichón and TVF present slight enrichments in K2O, Na2O, Rb, Sr, Th, U, Cs, and LREE respect to TVC, these are signatures related to subduction environment. The presence of alkaline magmas at El Chichón and TVF correspond to mantle low degree melts that reach the surface along with calc-alkaline lavas due to a tensional stress field that allows their pass to the surface. In the generation of the magmas of southern Mexico three components are involved: mantle partial melting fluids, fluid from subducted lithosphere, and continental crust, likely interacting in different ratios through time and in different proportions from SW to NE.

  7. Field project to obtain pressure core, wireline log, and production test data for evaluation of CO/sub 2/ flooding potential, Conoco MCA unit well No. 358, Maljamar Field, Lea County, New Mexico

    SciTech Connect

    Swift, T.E.; Marlow, R.E.; Wilhelm, M.H.; Goodrich, J.H.; Kumar, R.M.

    1981-11-01

    This report describes part of the work done to fulfill a contract awarded to Gruy Federal, Inc., by the Department of Energy (DOE) on Feburary 12, 1979. The work includes pressure-coring and associated logging and testing programs to provide data on in-situ oil saturation, porosity and permeability distribution, and other data needed for resource characterization of fields and reservoirs in which CO/sub 2/ injection might have a high probability of success. This report details the second such project. Core porosities agreed well with computed log porosities. Core water saturation and computed log porosities agree fairly well from 3692 to 3712 feet, poorly from 3712 to 3820 feet and in a general way from 4035 to 4107 feet. Computer log analysis techniques incorporating the a, m, and n values obtained from Core Laboratories analysis did not improve the agreement of log versus core derived water saturations. However, both core and log analysis indicated the ninth zone had the highest residual hydrocarbon saturations and production data confirmed the validity of oil saturation determinations. Residual oil saturation, for the perforated and tested intervals were 259 STB/acre-ft for the interval from 4035 to 4055 feet, and 150 STB/acre-ft for the interval from 3692 to 3718 feet. Nine BOPD was produced from the interval 4035 to 4055 feet and no oil was produced from interval 3692 to 3718 feet, qualitatively confirming the relative oil saturations as calculated. The low oil production in the zone from 4022 to 4055 and the lack of production from 3692 to 3718 feet indicated the zone to be at or near residual waterflood conditions as determined by log analysis. This project demonstrates the usefulness of integrating pressure core, log, and production data to realistically evaluate a reservoir for carbon dioxide flood.

  8. WIPP site and vicinity geological field trip. A report of a field trip to the proposed Waste Isolation Pilot Plant project in Southeastern New Mexico, June 16 to 18, 1980

    SciTech Connect

    Chaturvedi, L

    1980-10-01

    The Environmental Evaluation Group is conducting an assessment of the radiological health risks to people from the Waste Isolation Pilot Plant. As a part of this work, EEG is making an effort to improve the understanding of those geological issues concerning the WIPP site which may affect the radiological consequences of the proposed repository. One of the important geological issues to be resolved is the timing and the nature of the dissolution processes which may have affected the WIPP site. EEG organized a two-day conference of geological scientists, on January 17-18, 1980. On the basis of the January conference and the June field trip, EEG has formed the following conclusions: (1) it has not been clearly established that the site or the surrounding area has been attacked by deep dissolution to render it unsuitable for the nuclear waste pilot repository; (2) the existence of an isolated breccia pipe at the site unaccompanied by a deep dissolution wedge, is a very remote possibility; (3) more specific information about the origin and the nature of the brine reservoirs is needed. An important question that should be resolved is whether each encounter with artesian brine represents a separate pocket or whether these occurrences are interconnected; (4) Anderson has postulated a major tectonic fault or a fracture system at the Basin margin along the San Simon Swale; (5) the area in the northern part of the WIPP site, identified from geophysical and bore hole data as the disturbed zone, should be further investigated to cleary understand the nature and significance of this structural anomaly; and (6) a major drawback encountered during the discussions of geological issues related to the WIPP site is the absence of published material that brings together all the known information related to a particular issue.

  9. English Teaching Profile: Mexico.

    ERIC Educational Resources Information Center

    British Council, London (England). English Language and Literature Div.

    A profile of the extent of English usage and instruction in Mexico gives an overview of the following elements: its role and status alongside Spanish and within the educational system at all levels; teacher education; program accreditation; required reading skills; the supply and professional support of English teachers; the type and availability…

  10. Broadcasting in Mexico.

    ERIC Educational Resources Information Center

    de Noriega, Luis Antonio; Leach, Frances

    This monograph traces the growth of Mexico's broadcasting services against the background of that country's geographical, cultural, demographic, economic, and political structures. Specific areas dealt with within the six chapters of the monograph are: (1) the national environment for broadcasting; (2) the advent and development of broadcasting in…

  11. Many Faces of Mexico.

    ERIC Educational Resources Information Center

    Ruiz, Octavio Madigan; And Others

    This resource book braids together the cultural, political and economic realities which together shape Mexican history. The guiding question for the book is that of: "What do we need to know about Mexico's past in order to understand its present and future?" To address the question, the interdisciplinary resource book addresses key…

  12. [Food security in Mexico].

    PubMed

    Urquía-Fernández, Nuria

    2014-01-01

    An overview of food security and nutrition in Mexico is presented, based on the analysis of the four pillars of food security: availability, access, utilization of food, and stability of the food supply. In addition, the two faces of malnutrition in Mexico were analyzed: obesity and undernourishment. Data were gathered from the food security indicators of the United Nations's Food and Agriculture Organization, from the Mexican Scale of Food Security, and from the National Health and Nutrition Survey. Mexico presents an index of availability of 3 145 kilocalories per person per day, one of the highest indexes in the world, including both food production and imports. In contrast, Mexico is affected by a double burden of malnutrition: whereas children under five present 14% of stunt, 30% of the adult population is obese. Also, more than 18% of the population cannot afford the basic food basket (food poverty). Using perception surveys, people reports important levels of food insecurity, which concentrates in seven states of the Mexican Federation. The production structure underlying these indicators shows a very heterogeneous landscape, which translates in to a low productivity growth across the last years. Food security being a multidimensional concept, to ensure food security for the Mexican population requires a revision and redesign of public productive and social policies, placing a particular focus on strengthening the mechanisms of institutional governance.

  13. Workforce: New Mexico

    ERIC Educational Resources Information Center

    Western Interstate Commission for Higher Education, 2006

    2006-01-01

    In New Mexico, the demand for well-educated employees will only increase over the next several years. In the decade leading up to 2012, healthcare occupations will see growth of 32 percent. Teachers will be in high demand: nearly 12,380 educators (including librarians) will need to be hired. Managers will see their ranks swell by 21 percent; when…

  14. Literacy in Mexico

    ERIC Educational Resources Information Center

    Reyes, J. I.

    1971-01-01

    A Supreme Emergency Law launched the National Campaign Against Illiteracy in Mexico in 1944; it served to awaken the public conscience to this enormous social problem. Now literacy education is seen as a basis on which to create a higher cultural life. (EB)

  15. Mexico: Yesterday and Today.

    ERIC Educational Resources Information Center

    Koscielny, Mary Patrice

    This guide features Mexican history, culture, and the environment in the years past and present. This guide discusses five periods of Mexican history, including: (1) Indian Period; (2) Colonial Period; (3) Independence Movement; (4) The Revolution; and (5) Mexico Today. Each section has goals for the students, background readings, and activities…

  16. Real lives 3: Mexico.

    PubMed

    Werner, L

    1994-01-01

    Mexico City's earthquake of September 1985 killed 7000 people and destroyed tens of thousands of inner-city low-income housing units. It also spurred the growth of squatter settlements at the urban edge of the city. Dario Martinez is one such settlement, a colonia populare, to the city's south-east, just inside the federal district state of Mexico. Smoke pollution, garbage, open sewers, and industrial encroachment are typical for squatter settlements on the periphery. Even so, and despite the comparative lack of economic opportunity forcing people to commute to the city center for employment, the physical quality of life is better that what poor families can find further into the city. Residents in Mexico City are often told not to breathe when they go outside. The most common cause of urban flight in Mexico is therefore to escape the unhealthy environment. There are few urban services in the periphery such as electricity and piped water, but people do not suffer the problems of overcrowding, air pollution, chronic water shortages, and earthquake dangers.

  17. Mexico: Country Status Report.

    ERIC Educational Resources Information Center

    McFerren, Margaret

    A survey of the status of language usage in Mexico begins with an overview of language distribution among the population, mono- and multilingualism, changes in patterns of usage between the 1970 and 1980 censuses, and linguistic issues related to assimilation of the Indian population and the role and philosophy of the Instituto Nacional…

  18. Sierra University in Mexico

    ERIC Educational Resources Information Center

    Celis, Francisco Manuel Orozco

    2003-01-01

    Sierra University was designed to promote the development of the mountain communities in the State of Sonora, Mexico. The university offers high school graduates an opportunity to pursue their studies in their home region, in order to stimulate economic development and contribute to social cohesion in the highlands area. The university is equipped…

  19. Sierra University in Mexico

    ERIC Educational Resources Information Center

    Celis, Francisco Manuel Orozco

    2003-01-01

    Sierra University was designed to promote the development of the mountain communities in the State of Sonora, Mexico. The university offers high school graduates an opportunity to pursue their studies in their home region, in order to stimulate economic development and contribute to social cohesion in the highlands area. The university is equipped…

  20. Christmas in Mexico.

    ERIC Educational Resources Information Center

    Kern County Superintendent of Schools, Bakersfield, CA.

    The Christmas season in Mexico starts on December 16 with "las posadas," a series of religious processions in which families or neighbors reenact Joseph's search for shelter for Mary en route to Bethlehem. Those representing pilgrims travel from home to home until they are finally accepted by those representing innkeepers at a home with…

  1. The Art of Mexico.

    ERIC Educational Resources Information Center

    Saccardi, Marianne

    1997-01-01

    Provides an annotated bibliography of books for grades K and up which explores the folklore, poetry, fiction, and art of Mexico, and focuses on the Mayans and Aztecs and Diego Rivera and Frida Kahlo. Also suggests various research, reading, drama, music, social studies, physical education, and art activities and lists related videos and Internet…

  2. Broadcasting in Mexico.

    ERIC Educational Resources Information Center

    de Noriega, Luis Antonio; Leach, Frances

    This monograph traces the growth of Mexico's broadcasting services against the background of that country's geographical, cultural, demographic, economic, and political structures. Specific areas dealt with within the six chapters of the monograph are: (1) the national environment for broadcasting; (2) the advent and development of broadcasting in…

  3. Mexico: Country Status Report.

    ERIC Educational Resources Information Center

    McFerren, Margaret

    A survey of the status of language usage in Mexico begins with an overview of language distribution among the population, mono- and multilingualism, changes in patterns of usage between the 1970 and 1980 censuses, and linguistic issues related to assimilation of the Indian population and the role and philosophy of the Instituto Nacional…

  4. Vasculitis: report from Mexico.

    PubMed

    Flores-Suárez, Luis Felipe

    2013-10-01

    Although primary systemic vasculitides (PSV) are infrequent diseases, basic and clinical research have increased the knowledge of these autoimmune conditions substantially. Some PSV seem to be more frequent in certain countries. Here we present a brief history of the modest, but important contributions made in Mexico in this area of research.

  5. The Art of Mexico.

    ERIC Educational Resources Information Center

    Saccardi, Marianne

    1997-01-01

    Provides an annotated bibliography of books for grades K and up which explores the folklore, poetry, fiction, and art of Mexico, and focuses on the Mayans and Aztecs and Diego Rivera and Frida Kahlo. Also suggests various research, reading, drama, music, social studies, physical education, and art activities and lists related videos and Internet…

  6. Indians of New Mexico.

    ERIC Educational Resources Information Center

    Bureau of Indian Affairs (Dept. of Interior), Washington, DC.

    The booklet gives a general introduction to American Indians in New Mexico. Covering historical background and present status, reports are given for these tribes: the 19 Pueblos (i.e., Acoma, Cochiti, Isleta, Jemez, Laguna, and Zuni), the Jicarilla and Mescalero Apaches, and the Navajos. Also included are 26 places of interest such as Acoma…

  7. Christmas in Mexico.

    ERIC Educational Resources Information Center

    Kern County Superintendent of Schools, Bakersfield, CA.

    The Christmas season in Mexico starts on December 16 with "las posadas," a series of religious processions in which families or neighbors reenact Joseph's search for shelter for Mary en route to Bethlehem. Those representing pilgrims travel from home to home until they are finally accepted by those representing innkeepers at a home with…

  8. Colima Volcano, Mexico

    NASA Image and Video Library

    1995-10-29

    STS073-E-5274 (3 Nov. 1995) --- Colima was photographed with a color Electronic Still Camera (ESC) onboard the Earth-orbiting space shuttle Columbia. The volcano lies due south of Guadalajara and Lake Chapala. It is considered to be one of Mexico's most active and most dangerous volcanoes, lying not far from heavily populated areas.

  9. Comparison of Gulf of Mexico Wave Information Studies (WIS) 2-G Hindcast with 3-G Hindcasting

    DTIC Science & Technology

    2006-01-01

    recently completed twenty years (1980-1999) of wave hindcasts for the Gulf of Mexico using the second-generation wave model, WISWAVE. This wave...of three hindcasts using the same input wind fields and the same nested grid system. Results will be shown at available measurement sites for the 1995 Level 2 and Level 3 Gulf of Mexico hindcast.

  10. New Mexico Math Pathways Taskforce Report

    ERIC Educational Resources Information Center

    New Mexico Higher Education Department, 2016

    2016-01-01

    In April 2015 New Mexico faculty, Dana Center staff, and New Mexico Higher Education (NMHED) co-presented the need for better math pathways statewide. Faculty from 6 institutions (New Mexico State University, New Mexico Highlands University, Dine College, Eastern New Mexico University, El Paso Community College, and San Juan College) participated…

  11. Model assessing the impact of biomass burning on air quality and photochemistry in Mexico City

    NASA Astrophysics Data System (ADS)

    Lei, W.; Li, G.; Wiedinmyer, C.; Yokelson, R. J.; Molina, L. T.

    2010-12-01

    Biomass burning is a major global emission source for trace gases and particulates. Various multi-platform measurements during the Mexico City Metropolitan Area (MCMA)-2003 and Megacity Initiative: Local and Global Research Observations (MILAGRO)-2006 campaigns suggest significant influences of biomass burning (BB) on air quality in Mexico City during the dry season, and the observations show emissions from BB impose viable yet highly variable impacts on organic aerosols (OA) in and around Mexico City. We have developed emission inventories for forest fires surrounding Mexico City based on measurement-estimated emission factors and MODIS fire counts, and for garbage fires in Mexico City based on in situ-measured emission factors and the population distribution and socioeconomic data. In this study, we will comprehensively assess the impact of biomass burning on the aerosol loading, chemical composition, OA formation and photochemistry in Mexico City using WRF-Chem. Analysis of the model results, in conjunction with concurrent field measurements, will be presented.

  12. Smoke in the Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Sea-viewing Wide Field-of-view Sensor (SeaWiFS) image of the Bay of Campeche, acquired January 17, 2001, shows a 300-kilometer long smoke plume streaming towards the northwest from around 19.4o North and 92o West, the location of the Akal oil field. In the lower right (southeast) corner of the image is the country of El Salvador, site of a magnitude 7.6 earthquake on January 13, 2001. On the Pacific side of Southern Mexico, the productive waters of the Gulf of Tehuantepec are visible. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  13. Transmitted HIV drug resistance among drug-naive subjects recently infected with HIV in Mexico City: a World Health Organization survey to classify resistance and to field test two alternative patient enrollment methods.

    PubMed

    Bertagnolio, Silvia; Rodriguez-Diaz, Roberto A; Fuentes-Romero, Luis L; Bennett, Diane E; Viveros-Rogel, Monica; Hart, Stephen; Pilon, Richard; Sandstrom, Paul; Soto-Ramirez, Luis E

    2012-05-01

    In 2004, the World Health Organization performed a survey to assess transmitted drug resistance in Mexico City among drug-naive persons with newly diagnosed human immunodeficiency virus (HIV) infection and likely to be recently infected who were attending 3 voluntary counseling and testing sites. A parallel study comparing 2 alternative methods of enrolling survey participant was conducted in 9 voluntary counseling and testing sites in central Mexico. In study arm 1, subject information, consent and blood specimens were obtained during the HIV diagnostic testing visit. In study arm 2, consent and blood specimens were obtained at the return visit, only from those who were HIV infected. This survey classified nonnucleoside reverse-transcriptase inhibitor and nucleoside reverse-transcriptase inhibitor transmitted drug resistance as <5% and 5%-15%, respectively. Arm 2 yielded major advantages in cost and workload, with no evidence of increased sampling bias.

  14. Fast Identification of Near-Trench Earthquakes Along the Mexican Subduction Zone Based on Characteristics of Ground Motion in Mexico City

    NASA Astrophysics Data System (ADS)

    Perez-Campos, X.; Singh, S. K.; Arroyo, D.; Rodríguez, Q.; Iglesias, A.

    2015-12-01

    The disastrous 1985 Michoacan earthquake gave rise to a seismic alert system for Mexico City which became operational in 1991. Initially limited to earthquakes along the Guerrero coast, the system now has a much wider coverage. Also, the 2004 Sumatra earthquake exposed the need for a tsunami early warning along the Mexican subduction zone. A fast identification of near-trench earthquakes along this zone may be useful in issuing a reliable early tsunami alert. The confusion caused by low PGA for the magnitude of an earthquake, leading to "missed" seismic alert, would be averted if its near-trench origin can be quickly established. It may also help reveal the spatial extent and degree of seismic coupling on the near-trench portion of the plate interface. This would lead to a better understanding of tsunami potential and seismic hazard along the Mexican subduction zone. We explore three methods for quick detection of near-trench earthquakes, testing them on recordings of 65 earthquakes at station CU in Mexico City (4.8 ≤Mw≤8.0; 270≤R≤615 km). The first method is based on the ratio of total to high-frequency energy, ER (Shapiro et al., 1998). The second method is based on parameter Sa*(6) which is the pseudo-acceleration response spectrum with 5% damping, Sa, at 6 s normalized by the PGA. The third parameter is the PGA residual, RESN, at CU, with respect to a newly-derived ground motion prediction equation at CU for coastal shallow-dipping thrust earthquakes following a bayesian approach. Since the near-trench earthquakes are relatively deficient in high-frequency radiation, we expect ER and Sa*(6) to be relatively large and RESN to be negative for such events. Tests on CU recordings show that if ER ≥ 100 and/or Sa*(6) ≥ 0.70, then the earthquake is near trench; for these events RESN ≤ 0. Such an event has greater tsunami potential. Few misidentifications and missed events are most probably a consequence of poor location, although unusual depth and source

  15. Preliminary Field Report on the Findings and Results of the Evaluation of the Cultural and Historical Resources of the Las Cruces Arroyo Lithic Site (EPCM 32:106:10:3) in Las Cruces, New Mexico.

    DTIC Science & Technology

    1973-05-31

    began in early March of 1973 upon receiving approval from the Southwest Regional Office of the National Park Service in Santa Fe, New Mexico. An eva...were occasional areas of exposed gravels and caliche deposits on steep slopes where water erosion has been going on. The overlying sands vary in depth...10 .41 Fossil Tooth Enamel 5 3 Fossil Bone 2 1 2 Volcanic Scoria 9 8 2 Pottery: El Paso Brown I - N - 12. TABLE 1 (Cont.) Total Surface Surface (To

  16. Paleomagnetic results from northeastern Mexico: Evidence for large Mesozoic rotations

    NASA Astrophysics Data System (ADS)

    Gose, Wulf A.; Belcher, Robert C.; Scott, Gary R.

    1982-01-01

    Preliminary paleomagnetic evidence indicates that a significant part of Mexico rotated 130° counterclockwise during early Mesozoic time, coeval with the opening of the Gulf of Mexico, and that a major structural discontinuity must exist between Mexico and cratonic North America. Measurements made on samples from fourteen isolated outcrops of the Huizachal Group, a red-bed sequence exposed in northeastern Mexico indicate that these sediments were deposited in rifted basins and could range in age from post Middle Permian to pre Early Cretaceous. Of samples analyzed from the overlying Zuloaga Limestone (Oxfordian) and the Cuesta del Cura Formation (Aptian-Albian), the oldest yield a paleomagnetic pole position that implies that the sampling area was originally oriented about 130° clockwise relative to stable North America. Progressive counterclockwise rotation continued to Middle Jurassic time. Because of the limited geographical distribution of sampling sites, it is not possible to assess whether most of Mexico shared this rotation or whether the proposed left-lateral motion along major west-northwest trending faults caused the rotation of a smaller crustal block. In either case, our results strongly suggest a major structural discontinuity in northern Mexico. *Present address: Mobil Research and Development Corp., Field Research Laboratory, Dallas, Texas 75221

  17. [Dietary changes in Mexico].

    PubMed

    Ramírez Mayans, J A; García Campos, M; Cervantes Bustamante, R; Mata Rivera, N; Zárate Mondragón, F; Mason Cordero, T; Villarreal Espinosa, A

    2003-06-01

    Although the Mexican population has traditionally been malnourished, the prevalence of obesity in children and adults has increased by almost 50 % in the last 10 years. Recent studies show substantial changes in the nutritional status of Mexicans, especially in the pediatric population. Among the factors associated with the development of obesity are overeating, sedentariness, and genetics. The apparent economic development in Mexico, as well as the influence of dietary patterns from other countries, have contributed to modifying lifestyle. Despite measures taken by the health system, iron- and zinc-deficiency anemia continue to be prevalent. The present review aims to describe the changes that have taken place in Mexico in the last few decades leading to a generation of short and obese children, as well as to determine the associated factors in order to promote healthier eating patterns among the Mexican population.

  18. Neuropsychology in Mexico.

    PubMed

    Ostrosky Shejet, Feggy; Velez Garcia, Alicia

    2016-11-01

    This invited paper explores the diverse pathways that have led to the development of neuropsychology in Mexico. The authors conducted a review of the literature and their own experiences to describe the seminal events and people relevant to the development of this area of research and practice. The master's degree is the usual level of educational attainment for those who wish to practice clinical neuropsychology. As of now, there is not a board certification process in neuropsychology, although there is one in clinical psychology. Neuropsychology and other mental health disciplines in Mexico and Latin America have historically been poorly funded, and have lacked optimal means of communication as to research findings and clinical initiatives and standards. However, there is reason to think that this will be improved upon in coming years.

  19. [Metropolitan areas in Mexico, 1980].

    PubMed

    Negrete Salas, M E; Salazar Sanchez, H

    1986-01-01

    Urban trends in Mexico from 1960 to 1980 are analyzed using multivariate analysis techniques. The authors note that the total number of metropolitan regions has increased from 12 to 26 during this period. Differences between the stage in urbanization reached by the Mexico City region and other urban centers in the country are noted. In Mexico City, the authors observe a decline in the population of the central city region coupled with rapid growth in the surrounding municipalities. (SUMMARY IN ENG)

  20. Gulf of California, Mexico

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Sunglint on the water's surface reveals the complex pattern of currents in the Gulf of California in the vicinity of Tiburon and Angel de la Guarda Islands (29.0N, 113.0W). Mexico's state of Sonora and the Sonora Desert is on the mainland and the state of Baja California consists of the entire peninsula. The Pacific Ocean is under the coastal cloud cover on the Baja peninsula.

  1. Baja California, Mexico

    NASA Technical Reports Server (NTRS)

    1981-01-01

    An interesting view down the axis of Baja California, Mexico (26.5N, 113.0W). At the center of the Scene is Laguna Ojo de Liebre (Bay of Whales) which is a breeding area for the Pacific Grey Whale. The Sea of Cortez, also known as the Gulf of California, is to the left and the Pacific Ocean is to the right.

  2. Seismology in Mexico

    USGS Publications Warehouse

    Lomnitz, C.

    1982-01-01

    Mexico is situated at the intersection of four major crustal Plates: the Americas Plate, the Pacific Plate, the Caribbean Plate, and the Cocos Plate. The interaction of these four plates is very complex. The pattern of earthquake risk is, therefore, among the most complicated in the world. The average release of seismic energy each is 55x1021 ergs-more than twice the figure for California. 

  3. Baja California, Mexico

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Sunglint on the surface of the Sea of Cortez near the island of Tiburon (28.5 N, 112.5W) reveals intricate patterns of internal waves under the placid surface. Mexico's state of Sonora and the Sonora Desert is on the mainland and the state of Baja California consists of the entire peninsula. The large bay on the Pacific side of Baja is Laguna Ojo de Libre (Bay of Whales) which is a breeding area for the Pacific Grey Whales.

  4. MANZANO WILDERNESS, NEW MEXICO.

    USGS Publications Warehouse

    Maxwell, C.H.; Light, Thomas D.

    1984-01-01

    On the basis of a mineral survey the extreme southwestern part of the Manzano Wilderness, New Mexico has a probable mineral-resource potential for the occurrence of gold. A sample from one inactive mine in this area yielded concentrations of gold and silver. Other mines and prospects and associated geologic terrane have little promise for the occurrence of additional mineral resources. No other mineral or energy resource potential was identified in the study.

  5. Crustal Deformation Analysis at CGPS Sites Spanning Mexico

    NASA Astrophysics Data System (ADS)

    Vazquez, G. E.; Bennett, R. A.; Spinler, J. C.; Grejner-Brzezinska, D. A.

    2014-12-01

    We conducted a study using data from continuous Global Positioning System (CGPS) stations throughout Mexico to understand a variety of factors that may have an impact on crustal deformation of Mexico—a research topic investigated for many years. This arises from the fact that Mexico is directly influenced by the interactions between the North American, Pacific, Cocos, Caribbean and Rivera tectonic plates. We analyzed CGPS data originating from several networks covering Mexico. These stations have been installed to serve diverse purposes and applications, and are administered by diverse organizations that include government agencies and public universities. We evaluated a total of 80 CGPS stations operating in Mexico; where dual-frequency geodetic-grade GPS receivers collected data continuously during periods between 1994 and 2014.5, in order to provide a synoptic view of the crustal velocity field of Mexico. The CGPS sites located in the Mexican territory were processed with respect to 133 sites outside of Mexico (i.e., Caribbean, Pacific, South and North American plates) in order to evaluate crustal deformation in Mexico in the context of the relative motions among these tectonic plates. Given the heterogeneous nature of the available GPS networks, we performed an analysis of time-series in terms of their duration and precision, finding generally high precision. From the estimated crustal velocities, we observe that these are very comparable (± 1 mm) with respect to previously derived values for stations located at the Baja Peninsula and the Oaxaca—Guerrero region. In general, the behavior of the northern CGPS spanning Mexico are very consistent with North American plate motion.

  6. New Mexico Clean Energy Initiatives

    EPA Pesticide Factsheets

    This presentation addresses New Mexico oil and gas development, brownfields, mining development, renewable energy development, renewable resources, renewable standards, solar opportunities, climate change, and energy efficiency.

  7. [Obesity in Mexico].

    PubMed

    Dávila-Torres, Javier; González-Izquierdo, José Jesús; Barrera-Cruz, Antonio

    2015-01-01

    Excess body weight (overweight and obesity) is currently recognized as one of the most important challenges of public health in the world, given its size, speed of growth and the negative effect it has on the health of the population that suffers. Overweight and obesity significantly increases the risk of chronic no communicable diseases, premature mortality and the social cost of health. An estimated 90 % of cases of type 2 diabetes mellitus attributable to overweight and obesity. Today, Mexico is second global prevalence of obesity in the adult population, which is ten times higher than that of countries like Japan and Korea. With regard to children, Mexico ranks fourth worldwide obesity prevalence, behind Greece, USA and Italy. In our country, over 70 % of the adult population, between 30 and 60 years are overweight. The prevalence of overweight is higher in men than females, while the prevalence of obesity is higher in women than men. Until 2012, 26 million Mexican adults are overweight and 22 million obese, which represents a major challenge for the health sector in terms of promoting healthy lifestyles in the population and development of public policies to reverse this scenario epidemiology. Mexico needs to plan and implement strategies and action cost effective for the prevention and control of obesity of children, adolescents and adults. Global experience shows that proper care of obesity and overweight, required to formulate and coordinate multisectoral strategies and efficient for enhancing protective factors to health, particularly to modify individual behavior, family and community.

  8. Firearms in New Mexico.

    PubMed Central

    Wiktor, S Z; Gallaher, M M; Baron, R C; Watson, M E; Sewell, C M

    1994-01-01

    To determine the prevalence of firearm ownership and storage practices in New Mexico, we did a random-digit-dialing survey of New Mexico residents in October 1991. Of 200 households surveyed, 79 (40%) had 1 or more firearms in the home. Rural households were more likely than urban households to have firearms (44% versus 30%), and households with annual incomes of greater than $25,000 were more likely to have a firearm than households with incomes of $25,000 or less (41% versus 33%). Household firearm ownership did not vary with the presence of young (< 15 years old) children (38% with children versus 41% without). Handguns were generally owned for self-protection, and rifles were owned for hunting. Of households with firearms, 24% stored them unsafely (unlocked and loaded or unloaded but with ammunition nearby), including 21% of households with young children. Of the households with handguns only, 40% stored these firearms unsafely compared with 13% of those with rifles only. The prevalence of gun ownership in New Mexico is similar to that reported in national surveys; handguns are stored less safely than rifles; and the presence of young children in the home does not appear to improve firearm storage safety. Images PMID:7941530

  9. Environmental lead in Mexico.

    PubMed

    Albert, L A; Badillo, F

    1991-01-01

    From the data presented here, it can be concluded that environmental exposure to lead is a particularly severe problem in Mexico. As has been shown, there are very important sources of exposure to this metal: (a) for rural populations who manufacture and/or utilize lead-glazed pottery, (b) for urban populations who are exposed to high air lead concentrations due to the continued use of lead fuel additives, (c) for workers of several industries, mainly those of batteries and pigments, (d) for consumers who routinely eat canned foods such as hot peppers and fruit products, and (e) for the general population living in the vicinity of smelters, refineries and other industries that emit lead. Therefore, in Mexico only those native populations living in very primitive communities, far away from all civilized life, could be expected to be free from this exposure. At the same time, and despite the relatively few data available, it can be stated that the exposure to lead of populations in Mexico could be approaching levels that might be highly hazardous, in particular for the neuropsychological health of children. Regarding the presence of lead in the environment, despite the fact that the available studies are not enough, it is evident that pollution by this metal is widespread and that there is a serious lack of studies for most regions of the country, including several that might be expected to be highly polluted. At the same time, it is evident that the official attention paid to the problem, either in regulations, support of further studies, or implementation of effective control measures has been far from the level needed according to the available data. Lead in gasoline is still used at very high concentrations in all the country, with the exception of Mexico City and its surrounding area, while no studies have been carried out to determine the potential health and environmental impact of this practice in regions outside Mexico City. Despite the fact that the Torre

  10. Mexico: Rasgos de Su Historia. (Mexico: Highlights of Its History).

    ERIC Educational Resources Information Center

    Orozco, Cecilio

    Intended for both teachers and students, this publication, written in Spanish, briefly traces Mexico's history from its Conquest in 1519 to the overthrow of Porfirio Diaz in 1910. The following are briefly discussed: Mexico's Conquest in 1519; events immediately after the fall of Tenochtitlan; the War for Independence; Texas' separation from…

  11. Mexico 1996. Fulbright-Hays Summer Seminar Abroad 1996 (Mexico).

    ERIC Educational Resources Information Center

    Lopez, Salvador

    This paper shares the impressions of a participant from the 1996 Fulbright-Hays Summer Seminars Abroad Program in Mexico. These impressions address several current interest topics about international relations with Mexico including: (1) immigration; (2) politics; (3) education; (4) the economy; (5) the environment; (6) the media; (7) religion; and…

  12. Mexico: Rasgos de Su Historia. (Mexico: Highlights of Its History).

    ERIC Educational Resources Information Center

    Orozco, Cecilio

    Intended for both teachers and students, this publication, written in Spanish, briefly traces Mexico's history from its Conquest in 1519 to the overthrow of Porfirio Diaz in 1910. The following are briefly discussed: Mexico's Conquest in 1519; events immediately after the fall of Tenochtitlan; the War for Independence; Texas' separation from…

  13. Local Earthquake Velocity and Attenuation Tomography of the Jalisco, Mexico Region

    NASA Astrophysics Data System (ADS)

    Watkins, W. D.; Thurber, C. H.; Abbott, E. R.; Brudzinski, M.; Grand, S. P.

    2015-12-01

    The states of Jalisco, Colima, and Michoacan in western Mexico overlie the boundary of the subducting Rivera and Cocos plates, presenting an appealing target for seismological inquiry to better understand the resulting mantle flow and regional volcanism. The different dips between the subducting plates is thought to provide a mantle conduit that has contributed to the Colima Volcanic Complex, but there is considerable debate on the shallowness of the Rivera plate and width of the resulting conduit. With data from the Mapping the Rivera Subduction Zone (MARS) and Colima Deep Seismic Experiment (CODEX) networks, two temporary broadband arrays deployed in the region between 2006-2008, we invert for three-dimensional P- and S- wave velocity and later attenuation structure of the upper ~80 km of the crust and mantle in the Jalisco region. We improve upon previous tomography work by utilizing double-difference tomography, which enables the use of higher-accuracy differential times to sharpen the earthquake locations, and the inclusion of S-wave data. Current models that utilize only analyst-picked phase arrivals from 590 earthquakes yield P-wave high velocity anomalies that suggest a slab under the coastal regions at 15-25 km depth, and low velocity anomalies that may be related to Colima Volcano or other geologic features. Most of the S-wave model is poorly resolved. We will use a newly developed auto-picker to attempt to substantially increase the size of the S-wave dataset and to a lesser extent the P wave dataset, in order to densify ray coverage and improve model resolution. Additionally, we plan to employ the waveforms from this expanded dataset to compute a path attenuation operator for each arrival, which will then be used to invert for 3D P and S-wave attenuation models. The attenuation models combined with the velocity models will provide multiple constraints on physical properties of the crust in this region as well as those of specific geologic features.

  14. 33 CFR 166.200 - Shipping safety fairways and anchorage areas, Gulf of Mexico.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the erection of structures therein to provide safe approaches through oil fields in the Gulf of Mexico...) Louisiana Offshore Oil Port (LOOP) Shipping Safety Fairway to Safety Zone—(i) North of Gulf Safety Fairway...

  15. 33 CFR 166.200 - Shipping safety fairways and anchorage areas, Gulf of Mexico.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the erection of structures therein to provide safe approaches through oil fields in the Gulf of Mexico...) Louisiana Offshore Oil Port (LOOP) Shipping Safety Fairway to Safety Zone—(i) North of Gulf Safety Fairway...

  16. 33 CFR 166.200 - Shipping safety fairways and anchorage areas, Gulf of Mexico.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the erection of structures therein to provide safe approaches through oil fields in the Gulf of Mexico...) Louisiana Offshore Oil Port (LOOP) Shipping Safety Fairway to Safety Zone—(i) North of Gulf Safety Fairway...

  17. 33 CFR 166.200 - Shipping safety fairways and anchorage areas, Gulf of Mexico.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the erection of structures therein to provide safe approaches through oil fields in the Gulf of Mexico...) Louisiana Offshore Oil Port (LOOP) Shipping Safety Fairway to Safety Zone—(i) North of Gulf Safety Fairway...

  18. 33 CFR 166.200 - Shipping safety fairways and anchorage areas, Gulf of Mexico.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the erection of structures therein to provide safe approaches through oil fields in the Gulf of Mexico...) Louisiana Offshore Oil Port (LOOP) Shipping Safety Fairway to Safety Zone—(i) North of Gulf Safety Fairway...

  19. New Mexico, Arkansas Kroger Stores Compete in EPAs Sixth Annual Energy Star Battle of the Buildings

    EPA Pesticide Factsheets

    DALLAS - (July 22, 2015) Today, the Environmental Protection Agency (EPA) launched the 2015 Energy Star Battle of the Buildings. Kroger supermarkets and warehouses across New Mexico and Arkansas are among the groups fielding 6,500 buildings nationwi

  20. Mosses new to New Mexico

    USDA-ARS?s Scientific Manuscript database

    A bryophyte inventory was conducted in the Valles Caldera National Preserve (VCNP), New Mexico, from 2009 to 2011. Specimens representing 113 species of bryophytes were collected. Of those bryophytes, seven of the mosses were new to New Mexico: Atrichum tenellum (Rohling) Bruch & Schimper, Dicranum ...