Ostracode biofacies and shell chemistry reveal quaternary aquatic transitions in the Pozuelos basin (Argentina)
| Autor: | Andrew L. Kowler, María Camacho, Michael M. McGlue, Sarah J. Ivory, Gabriela Catalina Cusminsky, Manuel R. Palacios-Fest, Suvankar Chakraborty |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Delta
010506 paleontology Pleistocene QUATERNARY POZUELOS BASIN Structural basin 010502 geochemistry & geophysics 01 natural sciences Neotectonics Ciencias de la Tierra y relacionadas con el Medio Ambiente Paleontology Geología Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences OSTRACODA geography ARGENTINA geography.geographical_feature_category Alluvial fan Paleoecology Siliciclastic SHELL CHEMISTRY Quaternary Geology CIENCIAS NATURALES Y EXACTAS |
| Popis: | Here we present the first use of calcareous microfossils to examine the late Quaternary paleoecology of the endorheic Pozuelos Basin (Argentina). Modern deposition in the basin centers on Laguna de los Pozuelos (LP),a shallow playa-lake that is fed by axial rivers and groundwater and dominantly accumulates siliciclastic sediments.Today, the distribution of limnocytherid and cypridoidean ostracodes across southern LP is strongly influenced bydistance to the Rıo Cincel delta, whereas the northern end of the playa-lake is characterized by a paucity of ostracodes due to frequent sub-aerial exposure. Ten ostracode biofacies define a sediment core retrieved from LP,which reveal progressive changes in aquatic environments that varied in salinity, depth, and proximity to deltas over the late Pleistocene. Closed lakes occupied the basin from ~ 37.6?30.7 ka, ~ 28.0?25.0 ka, and ~ 23.0?16.6 ka,whereas saline wetlands occurred when these lakes contracted. Extant LP has no analog in the late Pleistocene record; it formed after ~ 7.2 ka, following a hiatus that removed the Pleistocene?Holocene transition.Paleoecological evidence indicates that the core site was influenced by deltaic inflows from the eastern basin margin until ~ 24.3 ka, an area where today dry alluvial fans are found. Reorganization of the watershed by normalfaulting, most likely at ~ 18.0 ka, appears to have reduced the influence of these deltaic inflows. Extensional neotectonics, perhaps induced by incorporation of the Pozuelos Basin into the Andean hinterland, is a mechanism that along with tropical climate change is potentially important to water balance and ecology in high-altitude convergent orogenic basins. Fil: McGlue, Michael M.. University of Kentucky; Estados Unidos Fil: Palacios Fest, Manuel R.. Terra Nostra Earth Sciences Research; Estados Unidos Fil: Cusminsky, Gabriela Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Camacho, Maria. Universidad Nacional de Jujuy; Argentina Fil: Ivory, Sarah J.. University of Kentucky; Estados Unidos. University Brown; Estados Unidos Fil: Kowler, Andrew L.. University of California; Estados Unidos Fil: Chakraborty, Suvankar. University of Utah; Estados Unidos |
| Databáze: | OpenAIRE |
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