Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia

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Autore principale: Juan-Luis García
Natura: Artículo científico
Lingua:en
Pubblicazione: Servicio Nacional de Geología y Minería 2015
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author Juan-Luis García
author_facet Juan-Luis García
contents Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia Juan-Luis García Jorge A. Strelin Rodrigo M. Vega Brenda L. Hall Charles R. Stern Ciencias de la Tierra Late glacial Push moraines Patagonian Ice Sheet Patagonian paleolakes The late-glacial sedimentologic and geomorphic record of the former Patagonian ice sheet remains mostly unstudied despite the fact that it affords invaluable evidence for glaciologic processes during the last glacial-interglacial transition (i.e., 18-11.5 ka). This information is critical if landforms (e.g., moraines) and associated sediments are to be used for paleoclimate reconstruction. El Canal stratigraphic section in Torres del Paine, southern Chile (51ºS), provides one of the few complete late-glacial morphostratigraphic records preserved on land in Patagonia that has not been reworked by postglacial lake or marine transgressions. Therefore, it provides unique evidence for reconstructing former environments, processes and fluctuations along the ice front at the end of the last glaciation. Here, we present results of a morphostratigraphic study of this site, which was shaped during the late-glacial Torres del Paine-TDP II, III and IV glacier fluctuations. We document the presence of eight sediment lithofacies associations and six stratigraphic sections that expose a complete record of proximal to distal subaqueous processes, which we link to phases of glacier advance (e.g., moraine building) and retreat. During the late-glacial, the Lago del Toro ice lobe pushed and glaciotectonized ice-contact lake sediments several times to shape the TDP moraine ridges fringing present-day lake. The saw-toothed morphology of the ridges confirms the structural origin of these landforms. Based on sediment facies associations, we conclude that local glacial lakes developed along the ice front during deposition of the late-glacial TDP II-IV moraine belts, suggesting that collapse, and associated continental drainage diversion, of major regional-size lakes in Torres del Paine had occurred during this time. 2015 artículo científico 0718-7092 https://www.redalyc.org/articulo.oa?id=173938242003 en http://www.redalyc.org/revista.oa?id=1739 Andean Geology application/pdf Servicio Nacional de Geología y Minería Andean Geology (Chile) Num.2 Vol.42
format Artículo científico
id redalyc_173938242003
institution Redalyc
language en
publishDate 2015
publisher Servicio Nacional de Geología y Minería
spellingShingle Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia
Juan-Luis García
Ciencias de la Tierra
Late
glacial
Push moraines
Patagonian Ice Sheet
Patagonian paleolakes
Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia Juan-Luis García Jorge A. Strelin Rodrigo M. Vega Brenda L. Hall Charles R. Stern Ciencias de la Tierra Late glacial Push moraines Patagonian Ice Sheet Patagonian paleolakes The late-glacial sedimentologic and geomorphic record of the former Patagonian ice sheet remains mostly unstudied despite the fact that it affords invaluable evidence for glaciologic processes during the last glacial-interglacial transition (i.e., 18-11.5 ka). This information is critical if landforms (e.g., moraines) and associated sediments are to be used for paleoclimate reconstruction. El Canal stratigraphic section in Torres del Paine, southern Chile (51ºS), provides one of the few complete late-glacial morphostratigraphic records preserved on land in Patagonia that has not been reworked by postglacial lake or marine transgressions. Therefore, it provides unique evidence for reconstructing former environments, processes and fluctuations along the ice front at the end of the last glaciation. Here, we present results of a morphostratigraphic study of this site, which was shaped during the late-glacial Torres del Paine-TDP II, III and IV glacier fluctuations. We document the presence of eight sediment lithofacies associations and six stratigraphic sections that expose a complete record of proximal to distal subaqueous processes, which we link to phases of glacier advance (e.g., moraine building) and retreat. During the late-glacial, the Lago del Toro ice lobe pushed and glaciotectonized ice-contact lake sediments several times to shape the TDP moraine ridges fringing present-day lake. The saw-toothed morphology of the ridges confirms the structural origin of these landforms. Based on sediment facies associations, we conclude that local glacial lakes developed along the ice front during deposition of the late-glacial TDP II-IV moraine belts, suggesting that collapse, and associated continental drainage diversion, of major regional-size lakes in Torres del Paine had occurred during this time. 2015 artículo científico 0718-7092 https://www.redalyc.org/articulo.oa?id=173938242003 en http://www.redalyc.org/revista.oa?id=1739 Andean Geology application/pdf Servicio Nacional de Geología y Minería Andean Geology (Chile) Num.2 Vol.42
title Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia
topic Ciencias de la Tierra
Late
glacial
Push moraines
Patagonian Ice Sheet
Patagonian paleolakes
url https://www.redalyc.org/articulo.oa?id=173938242003