Hydrogeochemical and nitrate isotopic evolution of a semiarid mountainous basin aquifer of glacial-fluvial and paleolacustrine origin (Lake Titicaca,Bolivia): the effects of natural processes and anthropogenic activities     

Flores Avil&#;s  Gabriela Patricia  Spadini  Lorenzo  Sacchi  Elisa  Rossier  Yvan  Savarino  Joel  Ramos  Oswaldo Eduardo  Duwig  C&#;line 《Hydrogeology Journal》2022,30(1):181-201

Hydrogeology Journal - A hydrogeochemical and stable isotopic ( $${\updelta }^{15}{\mathrm{N}}_{{\mathrm{NO}}_{3}}$$ and $${\updelta }^{18}{\mathrm{O}}_{{\mathrm{NO}}_{3}}$$ ) multitracer approach...  相似文献   

Fluid–Rock Interactions in Geothermal Reservoirs,Germany: Thermal Autoclave Experiments Using Sandstones and Natural Hydrothermal Brines     

Schäffer  Rafael  Götz  Emilia  Schlatter  Nils  Schubert  Gabriela  Weinert  Sebastian  Schmidt  Stefanie  Kolb  Ute  Sass  Ingo 《Aquatic Geochemistry》2022,28(2):63-110

As renewable energy, geothermal can contribute substantially to the energy transition. To generate electricity or to harvest heat, high-saline fluids are tapped by wells of a few kilometres and extracted from hydrothermal reservoirs. After the heat exchanger units have been passed by, these fluids are reinjected into the reservoir. Due to the pressure and temperature differences between the subsurface and the surface, as well as the cooling of the fluids in the power plant, unwanted chemical reactions can occur within the reservoir, in the borehole, and within the power plant itself. This can reduce the permeability of the reservoir as well as the output of the geothermal power plant. This study aims to simulate real subsurface reactions using batch and leaching experiments with sandstone or sandstone powder as solid phase, and deionised water or natural brine as liquid phase. It is demonstrated that fluid composition changes after only a few days. In particular, calcite, aragonite, clay minerals, and zinc phases precipitate from the natural brine. In contrast, in particular minerals containing potassium, arsenic, barium, and silica are dissolved. Due to the experimental set-up, these mineral reactions mainly took place on the surface of the samples, which is why no substantial changes in petrophysical properties could be observed. However, it is assumed that the observed reactions on the reservoir scale have a relevant influence on parameters such as permeability.

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Phytoplankton variation and its relation to nutrients and allochthonous organic matter in a coastal lagoon on the Gulf of Mexico     

Jos A. Ak-Castillo  Gabriela Vzquez 《Estuarine, Coastal and Shelf Science》2008,78(4):705-714

In tropical and subtropical zones, coastal lagoons are surrounded by mangrove communities which are a source of high quantity organic matter that enters the aquatic system through litter fall. This organic matter decomposes, becoming a source of nutrients and other substances such as tannins, fulvic acids and humic acids that may affect the composition and productivity of phytoplankton communities. Sontecomapan is a coastal lagoon located in the southern Gulf of Mexico, which receives abundant litter fall from mangrove. To study the phytoplankton composition and its variation in this lagoon from October 2002 to October 2003, we evaluated the concentrations of dissolved folin phenol active substances (FPAS) as a measure of plant organic matter, salinity, temperature, pH, O₂, N-NH₄⁺, N-NO₃⁻, P-PO₄³⁻, Si-SiO₂, and phytoplanktonic cell density in different mangrove influence zones including the three main rivers that feed the lagoon. Nutrients concentrations depended on freshwater from rivers, however these varied seasonally. Concentrations of P-PO₄³⁻, N-NH₄⁺ and FPAS were the highest in the dry season, when maximum mangrove litter fall is reported. Variation of these nutrients seemed to depend on the internal biogeochemical processes of the lagoon. Blooms of diatoms (Skeletonema spp., Cyclotella spp. and Chaetoceros holsaticus) and dinoflagellates (Peridinium aff. quinquecorne, Prorocentrum cordatum) occurred seasonally and in the different mangrove influence zones. The high cell densities in these zones and the occurrence of certain species and its ordination along gradient of FPAS in a canonical correspondence analysis, suggest that plant organic matter (i.e. mangrove influence) may contribute to phytoplankton dynamics in Sontecomapan lagoon.  相似文献   

Selenium in volcanic environments: A review   总被引：1，自引：0，他引：1  

Geerke H. Floor  Gabriela Román-Ross 《Applied Geochemistry》2012

Selenium is a chemical element with major environmental implications, due to the extremely narrow range between essential and toxic concentrations. Volcanoes emit significant amounts of Se, which has an enormous impact on the Se cycle and potentially human and animal health. This paper presents a broad overview of the current state of knowledge of major aspects of volcanic derived Se, focussing on the processes in soils and aquifers.  相似文献   

Using the photons from the Crab Nebula seen by GLAST to calibrate MAGIC and the imaging air Cherenkov telescopes     

D. Bastieri  C. Bigongiari  E. Bisesi  G. Busetto  A. De Angelis  B. De Lotto  T. Lenisa  F. Longo  M. Mariotti  A. Moralejo  D. Pascoli  L. Peruzzo  R. Rando  A. Saggion  P. Sartori  V. Scalzotto 《Astroparticle Physics》2005,23(6):572-576

In this article we discuss the possibility of using the observations by GLAST of standard gamma sources, as the Crab Nebula, to calibrate imaging air Cherenkov detectors, MAGIC in particular, and optimise their energy resolution. We show that at around 100 GeV the absolute energy calibration uncertainty of Cherenkov telescopes can be reduced to 10% by means of such cross-calibration procedure.  相似文献   

Transtensional fault-termination basins: an important basin type illustrated by the Pliocene San Jose Island basin and related basins in the southern Gulf of California, Mexico     

Paul J. Umhoefer  Tobias Schwennicke†  Maya T. Del Margo  Gabriela Ruiz-Geraldo†  James C. Ingle Jr.  ‡  William McIntosh§ 《Basin Research》2007,19(2):297-322

Transtensional basins are sparsely described in the literature compared with other basin types. The oblique‐divergent plate boundary in the southern Gulf of California has many transtensional basins: we have studied those on San Jose island and two other transtensional basins in the region. One major type of transtensional basin common in the southern Gulf of California region is a fault‐termination basin formed where normal faults splay off of strike‐slip faults. These basins suggest a model for transtensional fault‐termination basins that includes traits that show a hybrid nature between classic rift and strike‐slip (pull‐apart) basins. The traits include combinations of oblique, strike‐slip and normal faults with common steps and bends, buttress unconformities between the fault steps and beyond the ends of faults, a common facies pattern of terrestrial strata changing upward and away from the faults into marine strata, small fault blocks within the basin that result in complex lateral facies relations, common Gilbert deltas, dramatic termination of the margin of the basin by means of fault reorganization and boundary faults dying and an overall short basin history (few million years). Similar transtensional fault‐termination basins are present in Death Valley and other parts of the Eastern California shear zone of the western United States, northern Aegean Sea and along ancient strike‐slip faults.  相似文献   

Disrupting biogeochemical cycles - Consequences of damming   总被引：12，自引：0，他引：12  

Gabriela Friedl  Alfred Wüest 《Aquatic Sciences - Research Across Boundaries》2002,64(1):55-65

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Heavy metal and arsenic distributions in sediments of the Elba-Argentario basin, southern Tuscany, Italy   总被引：2，自引：0，他引：2  

Leonardo Leoni  F. Sartori 《Environmental Geology》1997,32(2):83-92

 Arsenic, chromium, cobalt, copper, lead, nickel, vanadium and zinc distributions in surficial and core sediments of the Elba-Argentario marine basin (southern Tuscany, central-western Italy) are reported. Analysis of such distributions compared with grain size and mineralogical data allowed the identification of areas showing trace element enrichments with respect to natural background. These enrichments are moderate and essentially restricted to Pb and Zn; only As shows a widespread, though not high, positive anomaly. This general pattern is in good agreement with the minor industrialization affecting the basin's watershed. An unexpected anomaly, concerning Co, Pb, and As, as well as Fe and Ti, has been pointed out close to Montecristo Island. This has been ascribed to illegal local dumping of chemical waste. Received: 12 January 1996 / Accepted: 9 September 1996  相似文献   

Sedimentary facies,depositional processes and climatic controls in a Triassic Lake,Tanzhuang Formation,western Henan Province,China     

María Gabriela Mángano  Luis Alberto Buatois  Xiantao Wu  Junmin Sun  Guocheng Zhang 《Journal of Paleolimnology》1994,11(1):41-65

The Middle to Upper Triassic Tanzhuang Formation represents part of the infill of the early Mesozoic Jiyuan-Yima Basin. The upper part of this stratigraphic unit records deposition within prevailing shallow lake conditions. Well-developed sequences crop out near Jiyuan, western Henan Province, central China. Six sedimentary facies clustered into two facies assemblages were recognized in the lacustrine section. Facies assemblage 1 consists of stacked coarsening-upward sequences composed, from base to top, of organic-rich shales (facies E, type I), laminated siltstones (facies A) and current-rippled laminated sandstones (facies B). Units of assemblage 1 record progradation of small mouth-bar deltas within a perennial open lacustrine system under temperate and humid conditions. Facies assemblage 2 lacks a clear vertical pattern and consists of interbedded fine-grained carbonates and siltstones (facies C); deformed and wave-reworked sandstones (facies D); organic-rich shales (facies E, type II) and clayey mudstones (facies F). The assemblage also represents a perennial, hydrologically-open, shallow lacustrine system, but characterized by strong seasonal climatic control. Water stratification probably occurred in several periods of the lake history. Pangaean megamonsoonal influence is envisaged to explain the strong seasonality imprint evidenced toward the upper part of the Tanzhuang lacustrine column.This is the fourth paper in a series of papers published in this issue on Climatic and Tectonic Rhythms in Lake Deposits.  相似文献   

The geology of the Oceanographer Transform: The transform domain     

P. J. Fox  R. H. Moody  J. A. Karson  E. Bonatti  W. S. F. Kidd  K. Crane  D. G. Gallo  J. B. Stroup  D. J. Fornari  D. Elthon  P. Hamlyn  J. F. Casey  D. Needham  R. Sartori 《Marine Geophysical Researches》1985,7(3):329-358

Three dives in submersible ALVIN and four deep-towed camera lowerings have been made along the transform valley of the Oceanographer Transform. These data constrain our understanding of the processes that create and shape the distinctive morphology that is characteristic of slowly slipping ridge-transform-ridge (RTR) plate boundaries. Our data suggest that the locus of strike-slip tectonism, called the transform fault zone (TFZ), is confined to a narrow swath (<4 km) that is centered along the axis of maximum depth. The TFZ is flanked by the inward facing slopes of the transform valley. The lower portions of the valley walls are characterized by broad sloping exposures of undisrupted sediment but at higher elevations the walls are made up of inward facing scarps and terraces of variable dimensions. Although the scarps have been badly degraded by mass wasting, there is no evidence to suggest that these scarps have accommodated significant amounts of strike-slip motion. Plutonic and ultramafic rocks are exposed on these scarps and the occurrence of this diverse assemblage on small-throw faults indicates that the crust is thin and/or discontinuous in this environment. We suggest that this complex igneous assemblage is the product of anomalous accretionary processes that are characteristic of slowly-slipping RTR plate boundaries.  相似文献