RESUMEN
Functional connectivity, the extent to which a landscape facilitates or impedes the dispersal of individuals across the landscape, is a key factor for the survival of species. Anthropogenic activities, such as urbanization, agriculture and roads, negatively impact functional connectivity of most species, particularly low-vagility species like lizards. Here, we examine how a landscape modified by anthropogenic activities affects the functional connectivity, at both broad and fine scales, of a widely distributed generalist lizard Sceloporus grammicus in the eastern Trans-Mexican Volcanic Belt, Mexico. We estimated for the first time the species' genetic structure, gene flow and functional connectivity in agricultural and forest zones using genomic data, a comprehensive landscape characterization and novel methods including gravity models. Our results showed not only marked genetic differentiation across the study region but also that functional connectivity is maintained for tens of kilometres despite S. grammicus low vagility. Specifically, we found that substrate and air temperature facilitated connectivity over broad and fine scales, respectively, while agricultural cover, relative humidity and slope were important for connectivity and gene flow. Contrastingly, forest cover and roads favoured (broad-scale) and limited (fine-scale) connectivity, likely associated with movement facilitated by small forest patches and with thermoregulation. Altogether, these results support that S. grammicus alternates its thermoregulatory behaviour depending on the distance travelled and the habitat environmental conditions, and that it can disperse through relatively modified landscapes, mainly using agricultural zones. The information obtained is crucial to understanding the response of lizards to current anthropogenic pressures and their potential to adapt.
Asunto(s)
Efectos Antropogénicos , Flujo Génico , Lagartos , México , Animales , Fenómenos Geológicos , Lagartos/genética , Lagartos/fisiología , Migración Animal , Agricultura , Genética de PoblaciónRESUMEN
In Colombia there are estimated to be over 121,000 missing people and victims of forced disappearances. Forensic investigators therefore need assistance in determining optimal detection techniques for buried victims, to give victims' families closure and for the wider community to see that justice is being served. Previous research has created 12 controlled simulated clandestine graves of typical Colombian murder victim scenarios at 0.5 m - 1.2 m depths in savannah and rainforest sites in Colombia. The 0-3 years of geophysical monitoring results of were published, with this paper reporting on 4-8 years monitoring of both UAV drone results and geophysical data. The UAV results from the year 8 survey, published for first time from Colombia, showed that the simulated graves could still be located using NDVI and NIR multi-spectral data, but not using optical or other multi-spectral data. The 0-3 years of geophysical data found the simulated clandestine graves could be detected with electrical resistivity and GPR methods, with the 4-8 year surveys evidencing that they could still be detected using bulk ground conductivity surveys, GPR horizontal time slice datasets and 2D ERT profiles. Research implications suggest initial use of UAV remote sensing technology to pinpoint likely search areas, before subsequent ground reconnaissance, geophysical surveys and their interpretation, before intrusive investigation methods are employed for detecting missing and disappeared persons in Colombia.
Asunto(s)
Entierro , Ciencias Forenses , Humanos , Colombia , Fenómenos Geológicos , Ciencias Forenses/métodos , Impedancia Eléctrica , América del Sur , TomografíaRESUMEN
In most Latin American countries, there are significant numbers of missing people and forced disappearances, over 120,000 in Colombia alone. Successful detection of shallow buried human remains by forensic search teams is difficult in varying terrain and climates. Previous research has created controlled simulated clandestine graves of murder victims to optimize search techniques and methodologies. This paper reports on a study on controlled test site results over four simulated dismembered victims' clandestine graves as this is sadly a common scenario encountered in Latin America. Multispectral images were collected once post-burial, electrical resistivity surveys were collected 4 times, and ground penetrating radar (GPR) surveys were collected three times up to the end of the 371 day survey monitoring period. After data processing, results showed that the multispectral data set could detect the simulated clandestine and control graves, with electrical resistivity imaging relative high resistances over some of the simulated graves but not over the empty control graves. GPR results showed good imaging on the Day 8 surveys, medium imaging on the Day 294 surveys, and medium to good imaging on the Day 371 surveys. Study implications suggest that, while clandestine graves of dismembered homicide victims would likely result in smaller-sized graves when compared to graves containing intact bodies, these graves can still potentially be detected using remote sensing and geophysical methods.
Asunto(s)
Entierro , Radar , Colombia , Impedancia Eléctrica , Fenómenos Geológicos , Derechos Humanos , Humanos , América del Sur , TomografíaRESUMEN
We combine U-Pb in-situ carbonate dating, elemental and isotope constraints to calibrate the synergy of integrated mountain-basin evolution in western Gondwana. We show that deposition of the Bambuí Group coincides with closure of the Goiás-Pharusian (630-600 Ma) and Adamastor (585-530 Ma) oceans. Metazoans thrived for a brief moment of balanced redox and nutrient conditions. This was followed, however, by closure of the Clymene ocean (540-500 Ma), eventually landlocking the basin. This hindered seawater renewal and led to uncontrolled nutrient input, shallowing of the redoxcline and anoxic incursions, fueling positive productivity feedbacks and preventing the development of typical Ediacaran-Cambrian ecosystems. Thus, mountains provide the conditions, such as oxygen and nutrients, but may also preclude life development if basins become too restricted, characterizing a Goldilocks or optimal level effect. During the late Neoproterozoic-Cambrian fan-like transition from Rodinia to Gondwana, the newborn marginal basins of Laurentia, Baltica and Siberia remained open to the global sea, while intracontinental basins of Gondwana became progressively landlocked. The extent to which basin restriction might have affected the global carbon cycle and climate, e.g. through the input of gases such as methane that could eventually have collaborated to an early Cambrian greenhouse world, needs to be further considered.
Asunto(s)
Evolución Biológica , Clima , Fenómenos Geológicos , Ciclo del Carbono , Ecosistema , Fósiles , Sedimentos Geológicos , Geología , Océanos y Mares , PaleontologíaRESUMEN
Introducción: El noroeste de Costa Rica representa un área con una alta riqueza geológica que evidencia rocas generadas en diferentes ambientes, como plano abisal, talud continental, plataforma continental, volcánicos continentales efusivos y explosivos, volcánicos submarinos, costeros, erosivos fluviales, erosivos gravitatorios, de intrusión y el manto terrestre. Objetivo: Describir el contexto geológico actual del noroeste de Costa Rica, mediante el análisis y recopilación de datos de campo, geoquímicos, petrológicos, estructurales, paleontológicos y radiométricos con el fin de reconstruir los eventos y etapas de deformación desde el Jurásico a la actualidad. Métodos: Se hizo una recopilación bibliográfica de estudios en diversas ramas geológicas para establecer un estado del arte del extremo noroeste de Costa Rica. Resultados: La historia geológica representa el registro en rocas desde el Jurásico al Holoceno - actualidad con once etapas definidas a partir de interpretaciones petrológicas, estructurales, geocronológicas, estratigráficas y paleontológicas agrupadas en tres etapas de depositación y afectadas por cuatro fases tectónicas compresivas. Conclusiones: Las etapas de depositación corresponden con una primera etapa magmática con afinidad oceánica entre el Jurásico y el Cretácico Superior, una segunda etapa predominantemente sedimentaria con un rango de edad entre el Cretácico Superior y el Oligoceno, y por último una etapa volcánica efusiva - explosiva ubicada desde el Plioceno hasta la actualidad. Las fases tectónicas se asocian con diferentes eventos entre placas. La primera se dio en el Cretácico Inferior y su principal resultado visible fue la emersión de la Ofiolita de Santa Elena; la segunda sucedió del Cretácico Superior temprano al Campaniano y su reconocimiento está ligado a la posición actual de la Ofiolita de Santa Elena y sus estructuras circundantes; la tercera fase aconteció desde el Eoceno Superior hasta el Mioceno y su principal producto fue la generación del tren de pliegues sedimentarios del Golfo de Santa Elena a bahía de Salinas; y por último se presenta una fase Cuaternaria que originó el eje de basculamiento de los productos piroclásticos frente a la cordillera volcánica de Guanacaste.
Introduction: The Costa Rican northwestern coastline has a wide geological uniqueness that exhibits rocks from different environments such as abyssal plane, continental slope, continental platform, volcanic eruptions (effusive, explosive, and submarine), coastal, erosional (fluvial and gravitatory), intrusions, and upper mantle rocks. Objective: To present the geologic state of the art of the northwestern coastline of Costa Rica through the bibliographic review of geochemical, petrologic, structural, paleontological and geochronological data. Methods: A bibliographic revision was done to propose a state of the art of northwestern coastline of Costa Rica. Results: The geologic record shows eleven stages from the Jurassic to the Holocene. These stages were regrouped from petrologic, structural, geochronologic, stratigraphic and paleontological interpretations in three depositional stages and four compressive tectonic phases. Conclusions: The first depositional stage is volcanic with oceanic affinity between the Jurassic and Upper Cretaceous. The second has a sedimentary predominance with an age range between the Upper Cretaceous and the Miocene. The last depositional stage is a volcanic (effusive and explosive) from the Pliocene until the present. The tectonic phases are associate with different interactions between tectonic plates. The first phase triggered the Santa Elena Ophiolite obduction during the Early Cretaceous. The second phase occurred in the Early Upper Cretaceous - Campanian and is recognized by its current position and surrounding structures. The third phase lasted from the Upper Eocene until the Miocene and its main result was the folding of the Bahía de Salinas sedimentary rocks. Finally, the Quaternary phase created a tilt axis and the aperture for the deposition of pyroclastic density currents in front of the Guanacaste volcanic ridge.
Asunto(s)
Tectónica , Fenómenos Geológicos , Sedimentación , Erupciones Volcánicas/análisis , Costa Rica , Geología/estadística & datos numéricosRESUMEN
Intriguing latest Eocene land-faunal dispersals between South America and the Greater Antilles (northern Caribbean) has inspired the hypothesis of the GAARlandia (Greater Antilles Aves Ridge) land bridge. This landbridge, however, should have crossed the Caribbean oceanic plate, and the geological evolution of its rise and demise, or its geodynamic forcing, remain unknown. Here we present the results of a land-sea survey from the northeast Caribbean plate, combined with chronostratigraphic data, revealing a regional episode of mid to late Eocene, trench-normal, E-W shortening and crustal thickening by â¼25%. This shortening led to a regional late Eocene-early Oligocene hiatus in the sedimentary record revealing the location of an emerged land (the Greater Antilles-Northern Lesser Antilles, or GrANoLA, landmass), consistent with the GAARlandia hypothesis. Subsequent submergence is explained by combined trench-parallel extension and thermal relaxation following a shift of arc magmatism, expressed by a regional early Miocene transgression. We tentatively link the NE Caribbean intra-plate shortening to a well-known absolute and relative North American and Caribbean plate motion change, which may provide focus for the search of the remaining connection between 'GrANoLA' land and South America, through the Aves Ridge or Lesser Antilles island arc. Our study highlights the how regional geodynamic evolution may have driven paleogeographic change that is still reflected in current biology.
Asunto(s)
Fenómenos Geológicos , Animales , Región del Caribe , Foraminíferos , Puerto RicoRESUMEN
The Guaraní Aquifer System (SAG) is the largest transboundary aquifer in Latin America, extending beneath parts of Brazil, Paraguay, Argentina, and Uruguay. This paper presents the results of recent hydrogeological studies in the southern portion of the SAG. Locally, the abundance of surface water bodies precluded the use of conventional hydrological tools to characterize groundwater flows. Geological, hydrochemical and environmental isotope investigations were integrated to postulate a revised hydrogeological conceptual model. The revised geological model has provided a better definition of the geometry of the aquifer units and outlined the relevance of regional faults in controlling flow patterns. The new potentiometric map is consistent with groundwater flow from the SAG outcrops to the centre of the Corrientes Province, where upwards flows were identified. Hydrochemical and isotope data confirmed the widespread occurrence of mixing. Noble gas isotopes dissolved in groundwater (4He and 81Kr/Kr) provided residence times ranging from recent recharge up to 770 ± 130 ka. Groundwater age modelling confirmed the role of the geological structures in controlling groundwater flow. The southern sector of the SAG is a multilayer aquifer system with vertical flows and deep regional discharge near the Esteros del Iberá wetland area and along the Paraná and Uruguay rivers.
Asunto(s)
Monitoreo del Ambiente/métodos , Agua Subterránea/química , Helio/análisis , Radioisótopos de Criptón/análisis , Ríos/química , Ciclo Hidrológico , Argentina , Brasil , Fenómenos Geológicos , Modelos Teóricos , Contaminantes Químicos del Agua/análisisRESUMEN
In the eastern region of central Costa Rica, land use in the sub-basins of the Maravilla-Chiz and Quebrada Honda rivers (47â km2) is dominated by agricultural and livestock production, while groundwater resources constitute the main drinking water supply. This study aimed to (a) evaluate the location of groundwater recharge areas and groundwater flow paths, and (b) provide a characterization of the hydrochemistry and possible anthropic impacts. Groundwater was collected from 20 sites during the dry and rainy seasons and analysed for major ions, water stable isotopes and 222Rn. Approximated recharge areas were estimated through a local altitudinal line based on isotopic compositions in springs. The hydrochemical and isotopic characterization of groundwater showed that the main recharge areas occur in the upper part of the basin, except for springs in the middle part of the basin probably due to a certain hydraulic disconnection from the upper part that facilitates local recharge processes. In the lower basin, groundwater exhibited greater transit times and longer flow paths. Low nitrate, chloride and sulphate concentrations found in groundwater indicate low leaching of fertilizers or urban wastewaters. Our results are focused to improve water resources and agricultural management plans in a dynamic tropical landscape.
Asunto(s)
Monitoreo del Ambiente/métodos , Fenómenos Geológicos , Agua Subterránea/química , Isótopos/análisis , Ciclo Hidrológico , Abastecimiento de Agua , Altitud , Costa Rica , Nitratos/análisis , Ríos/química , Estaciones del Año , Clima Tropical , Contaminantes Químicos del Agua/análisis , Recursos Hídricos/provisión & distribuciónRESUMEN
Sustainable groundwater management implies a good knowledge of recharge processes, especially in areas with water deficit, like the semi-arid region of Banabuiú watershed (Ceará State, Northeast of Brazil). In this zone, phreatic aquifers consist of Precambrian crystalline fractured reservoirs characterised by a high spatial anisotropy, both in terms of hydrodynamics and water quality. This study implemented a multi-tracer approach (18O, 2H, 14C, 3H, CFC, SF6), combined with hydrodynamic data (i.e. groundwater levels) to identify the groundwater recharge origin and the recharge mechanisms, and to estimate the groundwater residence time. At the basin scale, hydrodynamic data and local observations indicated the high reactivity of aquifers to precipitation and suggested that infiltration processes occur mostly through preferential infiltration zones. Stable isotope data showed a major contribution of evaporated surface water in the recharge process from many artificial or natural ponds. Groundwater residence time determination highlighted the spatio-temporal heterogeneity of flow path organisation within aquifers, with variable contributions between fast vertical flow (present-day end-member; 15-85â %) and a slower horizontal flow (old end-member <1960), underlining the vulnerability of aquifers to present-day environmental stress or pollution.
Asunto(s)
Monitoreo del Ambiente/métodos , Agua Subterránea/química , Isótopos/análisis , Estanques/química , Brasil , Clima Desértico , Sequías , Fenómenos Geológicos , Agua Subterránea/análisis , HidrodinámicaRESUMEN
The objective of this work is to enhance the conceptual hydrogeological model in the Río Cuarto River basin by using isotope and hydrochemical techniques. The precipitation pattern, as reflected in the average values of δ 2H and δ 18O in stations located in the plains and in the mountains, showed an isotope depletion from the East to the West, attributed to continental and altitude effects. Groundwater quality is mainly the result of two controlling factors: lithology and flow distances from recharge. The aquifers show fresh calcium/sodium bicarbonate water in the upper and medium basin (coarse fluvial sediments) which evolve to sodium sulphate and chloride waters in the low basin (mainly loess and fine alluvial sediments). The confined aquifer systems in the lower basin (C and D systems) averaged more negative stable isotope values, indicating that groundwater recharged during colder climatic conditions (Pleistocene period). Groundwater dating with 14C confirmed that groundwater ages range from modern to 45,000 years BP showing that as the water flows towards deeper layers and farther from the mountainous recharge area, groundwater age increases. The confined aquifers can potentially be exploited in order to partly cover different water needs but they should be managed in a sustainable way.
Asunto(s)
Monitoreo del Ambiente/métodos , Agua Subterránea/química , Isótopos/análisis , Modelos Teóricos , Sustento , Argentina , Fenómenos Geológicos , Agua Subterránea/normas , Ríos/química , Factores de Tiempo , Movimientos del Agua , Recursos Hídricos/provisión & distribución , Abastecimiento de Agua/normasRESUMEN
Despite being among the largest turtles that ever lived, the biology and systematics of Stupendemys geographicus remain largely unknown because of scant, fragmentary finds. We describe exceptional specimens and new localities of S. geographicus from the Miocene of Venezuela and Colombia. We document the largest shell reported for any extant or extinct turtle, with a carapace length of 2.40 m and estimated mass of 1.145 kg, almost 100 times the size of its closest living relative, the Amazon river turtle Peltocephalus dumerilianus, and twice that of the largest extant turtle, the marine leatherback Dermochelys coriacea. The new specimens greatly increase knowledge of the biology and evolution of this iconic species. Our findings suggest the existence of a single giant turtle species across the northern Neotropics, but with two shell morphotypes, suggestive of sexual dimorphism. Bite marks and punctured bones indicate interactions with large caimans that also inhabited the northern Neotropics.
Asunto(s)
Evolución Biológica , Extinción Biológica , Paleontología , Tortugas/anatomía & histología , Exoesqueleto/anatomía & histología , Animales , Tamaño Corporal , Peso Corporal , Huesos/anatomía & histología , Clima , Dieta , Femenino , Geografía , Fenómenos Geológicos , Masculino , Filogenia , Factores de Tiempo , VenezuelaRESUMEN
The sustainable use of soil requires a broad knowledge of its genesis, morphology, properties, and distribution in the landscape. Thus, the objective of this study was to characterize the pedogenetic attributes of representative soils from the cerrado-caatinga transition of the Gurguéia river basin to indicate their agricultural potential and limitations for the implementation of agroforestry systems. National and international soil classification systems were used to define the soil classes. The limiting factors and agricultural potential were characterized following the evaluation system of the agricultural potential of Brazilian land. In general, profiles 1, 3, 5, and 6 had a low nutrient budget and a sandy to loam texture. Profiles 2, 4, and 7 showed high clay content and nutrient budget. The soil profiles were classified as Ustic Quartzipsamments, Udic Haplusterts, Xanthic Haplustox, Arenic Kanhaplustults, Typic Haplustox, and Aridic Dystrustept based on their pedogenetic characteristics. Udic Haplusterts and Arenic Kanhaplustults soils display restrictions regarding the planting of forests owing to oxygen and soil depth limitations. The other soil classes had adequate physical properties for the implementation of agricultural systems and pastures, including good drainage and medium texture; however, they had low natural fertility, and thus require technologies for soil acidity correction and fertilization. Ustic Quartzipsamments and Ustic soils require the implementation of conservation systems, such as agroforestry, to avoid degradation.(AU)
O uso do solo de forma sustentável requer um amplo conhecimento sobre sua gênese, morfologia, propriedades e distribuição na paisagem. Dessa forma, objetivou-se com esta pesquisa realizar a caracterização pedogenética dos solos representativos da transição cerrado-caatinga da bacia hidrográfica do rio Gurguéia a fim de indicar sua aptidão e limitações para a implantação de sistemas agroflorestais. A caracterização baseou-se no estudo morfológico e na análise química e física dos horizontes de sete perfis de solos. Os sistemas de classificação de solos nacional e internacional foram utilizados para definir as classes de solos existentes na área pesquisada. Os fatores limitantes e a aptidão agrícola dos solos foram caracterizados conforme preposto no sistema de avaliação da aptidão agrícola de terras do Brasil. De forma geral, os perfis 1, 3, 5 e 6 apresentam baixa reserva de nutrientes e textura arenosa a média. Os perfis 2, 4 e 7 possuem maiores teores de argila e maior reserva de nutriente. Diante das características pedogenéticas dos perfis, pôde-se classificar os perfis de solo como NEOSSOLO QUARTZARÊNICO Órtico latossólico; VERTISSOLO HIDROMÓRFICO Órtico típico, LATOSSOLO AMARELO Distrófico típico, ARGISSOLO AMARELO Distrófico Abrúptico, LATOSSOLO VERMELHOAMARELO Distrófico argissólico e CAMBISSOLO HÁPLICO Tb Eutrófico típico respectivamente. Os VERTISSOLOS e CAMBISSOLOS presentam restrições a implantação de florestas devido à restrição de oxigênio e restrição a profundidade do solo. As demais classes de solos apresentaram propriedades físicas adequadas para a implantação de sistemas agrícolas e pastagens, incluindo boa drenagem e textura média; no entanto, tinham baixa fertilidade natural e, portanto, requerem correção da acidez do solo e adubação. Os solos NEOSSOLOS e ARGISSOLOS requerem a implementação de sistemas de conservação, como as agroflorestas, para evitar sua degradação.(AU)
Asunto(s)
24444 , Usos del Suelo , Análisis del Suelo , Brasil , Fenómenos GeológicosRESUMEN
What controls the formation of patchy substrates of white sand vegetation in the Amazonian lowlands is still unclear. This research integrated the geological history and plant inventories of a white sand vegetation patch confined to one large fan-shaped sandy substrate of northern Amazonia, which is related to a megafan environment. We examined floristic patterns to determine whether abundant species are more often generalists than the rarer one, by comparing the megafan environments and older basement rocks. We also investigated the pattern of species accumulation as a function of increasing sampling effort. All plant groups recorded a high proportion of generalist species on the megafan sediments compared to older basement rocks. The vegetation structure is controlled by topographic gradients resulting from the smooth slope of the megafan morphology and microreliefs imposed by various megafan subenvironments. Late Pleistocene-Holocene environmental disturbances caused by megafan sedimentary processes controlled the distribution of white sand vegetation over a large area of the Amazonian lowlands, and may have also been an important factor in species diversification during this period. The integration of geological and biological data may shed new light on the existence of many patches of white sand vegetation from the plains of northern Amazonia.
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Sedimentos Geológicos , Fenómenos Geológicos , Melastomataceae , Tracheophyta , Brasil , Geografía , ArenaRESUMEN
The unsuitable construction of unpaved roads has been causing problems related to the formation of erosive processes, sediments in watersheds, bogs, flooding, and holes. Presuming that the areas where flow accumulation intersects unpaved roads represent risk points, our objectives are (1) to develop a qualitative method based on the GIS software management tool (FlowAccRoad) for the identification of the intersection points between flow accumulation and roads and (2) to verify the discrepancy between the points of intersection produced by digital elevation models (DEM) accounting for different spatial resolutions. In the GIS environment, we used the Shuttle Radar Topography Mission (SRTM) and Goiania (GOI) digital elevation models for the modeling of flow accumulation and vectorization of the unpaved roads, both of which are based on the Bandeira Stream Watershed in Goiania, Goiás, Brazil. This highlights that 54 points of intersection between the flow accumulation and unpaved roads present problems related to erosive processes and quagmires, among others. The FlowAccRoad method identified the principal critical points observed in the field, using both the DEM of 30.4 m of spatial resolution (SRTM) and also of 4.8 m of spatial resolution (GOI). From the FlowAccRoad method, we observed that 91% of the risk points identified through the GOI DEM were located less than 20 m from valid points in the field by using GPS. Analyzing the SRTM DEM, only 45% of the critical risk points identified by the method were located less than 20 m from valid points in the field.
Asunto(s)
Monitoreo del Ambiente/métodos , Fenómenos Geológicos , Brasil , Inundaciones , Radar , Ríos , HumedalesRESUMEN
The potential of karst aquifers as a drinking water resource is substantial because of their large storage capacity gained in the course of carbonate dissolution. Carbonate dissolution and consequent development of preferential paths are also the reasons for the complex behavior of these aquifers as regards surface and underground flow. Hydrological modeling is therefore of paramount importance for an adequate assessment of flow components in catchments shaped on karsts. The cross tabulation of such components with geology, soils, and land use data in Geographic Information Systems helps decision makers to set up sustainable groundwater abstractions and allocate areas for storage of quality surface water, in the context of conjunctive water resources management. In the present study, a hydrologic modeling using the JAMS J2000 software was conducted in a karst area of Jequitiba River basin located near the Sete Lagoas town in the state of Minas Gerais, Brazil. The results revealed a very high surface water component explained by urbanization of Sete Lagoas, which hampers the recharge of 7.9 hm3 yr-1 of storm water. They also exposed a very large negative difference (-8.3 hm3 yr-1) between groundwater availability (6.3 hm3 yr-1) and current groundwater abstraction from the karst aquifer (14.6 hm3 yr-1), which is in keeping with previously reported water table declines around drilled wells that can reach 48 m in old wells used for public water supply. Artificial recharge of excess surface flow is not recommended within the urban areas, given the high risk of groundwater contamination with metals and hydrocarbons potentially transported in storm water, as well as development of suffosional sinkholes as a consequence of concentrated storm flow. The surface component could however be stored in small dams in forested areas from the catchment headwaters and diverted to the urban area to complement the drinking water supply. The percolation in soil was estimated to be high in areas used for agriculture and pastures. The implementation of correct fertilizing, management, and irrigation practices are considered crucial to attenuate potential contamination of groundwater and suffosional sinkhole development in these areas.
Asunto(s)
Conservación de los Recursos Hídricos , Modelos Teóricos , Recursos Hídricos , Brasil , Fenómenos Geológicos , Hidrología , Urbanización , Abastecimiento de AguaRESUMEN
The reviewed and integrated geoheritage inventory of the northern coast of the state of São Paulo, Brazil, resulted in 43 geosites distributed in eight geological frameworks. The selected geosites are representative of a geological history from the Neoproterozoic (Brasiliano-Pan African Cycle) to the recent, covering a minimum 700-Ma timespan. Considering the dynamic character of geoheritage inventories, the results presented in this work were based on previous local, town-based surveys, which were reviewed under the light of new geological data and geoconservation methods. Both qualitative and quantitative geosites assessments were used to discuss their geological representativeness and relevance, as well as legal aspects regarding protection and perspectives for future use. This resulted in a detailed inventory that reflects the current geological knowledge in the northern coast of the state of São Paulo, and may be used to make a general diagnosis of the scientific value, state of conservation, risk of degradation and potential use of the geoheritage. Moreover, it reinforces the importance of locally- and regionally-relevant sites for sustainable land management using geoheritage and to direct the decisions related to the conservation and use of this abiotic part of nature in the region.
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Conservación de los Recursos Naturales , Fenómenos Geológicos , Brasil , Sistemas de Información Geográfica , Geología/métodos , RegistrosRESUMEN
Characterized by fluvio-alluvial sedimentation processes, the heterogeneity in the Pantanal Basin allows its division in several sub-regions, which present natural characteristics of their own. It is possible to find in the literature different proposals to subdivide the Pantanal plain, which vary in total area and number of sub-regions. Each author uses specific criteria - mainly vegetation, soil and humidity - in his delimitation, but does not consider the tectonic aspects of the basin. In this sense, we intend to analyze three Pantanal delimitations from the literature and to relate them to the neotectonic context of the Pantanal plain by comparing the boundaries proposed in the delimitations to structural lineaments present in the basin. As a result, we observe that the comparison of the Pantanal boundaries with the lineaments shows a high compatibility between them, suggesting the influence of these structures in the development of the sub-regions.
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Monitoreo del Ambiente , Fenómenos Geológicos , Brasil , Paraguay , Ríos , Imágenes SatelitalesRESUMEN
Here we reconstructed the demographical history and the dispersal dynamics of Physalemus cuvieri through the Neogene-Quaternary periods by coupling DNA regions with different mutation rates, ecological niche modelling, reconstruction of spatio-temporal lineage dispersal and coalescent simulations. Still, to test alternative diversification scenarios we used approximate Bayesian computation. Molecular phylogenetic analysis recovered four deep and strongly supported clades, which we interpret as population lineages. The ancestral location reconstruction placed the root in southcentral Amazonia, and the dispersal events indicate that spatial displacement was widespread early in the diversification of this species. The demographical scenario of "Multiple Refugia" with recent lineage admixture was the most likely hypothesis to predict the observed genetic parameters of P. cuvieri. Our results revealed that Neogene orogenic events might have played a prominent role in the early diversification of P. cuvieri. The species shows deep divergences with strong regional population structure, despite its widespread distribution. Final uplift of the central Brazilian Plateau and formation of the river basins in Central South America played an important role in the origin, diversification and the maintenance of P. cuvieri lineages.
Asunto(s)
Anuros/clasificación , Clima , Fenómenos Geológicos , Clima Tropical , Animales , Anuros/genética , Teorema de Bayes , Brasil , ADN Mitocondrial/genética , Ecosistema , Variación Genética , Genética de Población , Haplotipos/genética , Modelos Teóricos , Filogenia , Filogeografía , Probabilidad , Factores de TiempoRESUMEN
In forensic geophysical research, using controlled experiments assists forensic search practitioners in identifying optimal technique(s) and equipment configuration(s) in different burial scenarios. The objective of the research is to observe the geophysical response to different types of buried wrappings, taking into consideration the influence that the presence or absence of a decomposing body (pig carcass) in a lateritic soil in central-western Brazil can have. In this article, the GPR results are presented after a 15day burial period during the rainy season, and the results of Electrical resistivity tomography (ERT) after a burial period of 6 months during the dry season. The controlled site was built in the research area of the University of Brasília, in a region with soil, typical of the Brazilian savannah. 14 simulated clandestine graves of murder victims were constructed, in which seven pig carcasses were wrapped or covered by: soil (backfill), a plastic bag, a bed sheet, cement block, construction debris, a wooden coffin and hydrated lime, respectively a further seven burials, presenting only the wrappings acted as comparison (control burial). During the GPR survey a 400MHz frequency antenna was used. The resistivity surveys were carried out before and after the burial of the targets with dipole-dipole and Wenner-Schlumberger array configurations, with different spacing of electrodes (1.00 and 0.50m). The comparison between the various scenarios with and without pig carcasses revealed that good reflection events occurred mainly due to the wrappings and that pig carcasses attenuated the GPR signal. Electrical resistivity results showed that the Wenner-Schlumberger array presents a better resolution of the lateral boundaries of the burials, and the dipole-dipole array presents a better sensitivity to heterogeneity of the buried materials. The burials with the pig carcasses wrapped in the various materials presented better resistivity contrasts as opposed to the control burials.
Asunto(s)
Restos Mortales , Entierro , Impedancia Eléctrica , Fenómenos Geológicos , Radar , Animales , Brasil , Ciencias Forenses , Modelos Animales , Cambios Post Mortem , PorcinosRESUMEN
The central part of Jalisco, Mexico, has experienced low-magnitude earthquake sequences and swarms. Although the effects of these earthquakes have been limited to relatively small areas, the earthquakes have caused general alarm among the population and, in some cases, have been catastrophic. These earthquake swarms are significant because they affect the most populous area of the state, including the capital city of Guadalajara. An extraordinary example is an earthquake swarm that started on 8 May 1912 and lasted until September of that year. The region remained seismically quiescent until May 2012, when seismic activity resumed, lasting to the present. We analyze the recent seismic activity, starting with the earthquake of 18 May 2012 (03:07 UT) at the western edge of Lake Chapala and ending with the magnitude 4.2 earthquake on 3 November 2016. Our analysis includes eight earthquakes with magnitudes between 3.5 and 4.8, the revision of hypocenter locations, and the determination of focal mechanism solutions using the inversion of the moment tensor method. When possible, inversion solutions are compared with solutions obtained with the first arrival polarity method. We compare our results for the recent seismicity with the distribution of reported damage associated with historical earthquakes. Our work indicates a N-S trending seismic source zone and an orientation of nodal planes that suggests reactivation of preexisting local faults induced by the interaction of the western border of the Trans-Mexican Volcanic Belt with the eastern border of the Jalisco Block.