Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina)
Abstract: Central Argentina from the Pampean flat‐slab segment to northern Patagonia (27°–41°S) represents a classic example of a broken retroarc basin with strong tectonic and climatic control on fluvial sediment transport. Combined with previous research focused on coastal sediments, this actualis...
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ftcdlib:oai:escholarship.org:ark:/13030/qt2dk3z0m4 2024-02-27T08:41:40+00:00 Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) Garzanti, Eduardo Capaldi, Tomas Vezzoli, Giovanni Limonta, Mara Sosa, Numa 3406 - 3437 2021-12-01 application/pdf https://escholarship.org/uc/item/2dk3z0m4 unknown eScholarship, University of California qt2dk3z0m4 https://escholarship.org/uc/item/2dk3z0m4 CC-BY Basin Research, vol 33, iss 6 Physical Geography and Environmental Geoscience Earth Sciences Geochemistry Geology Geophysics article 2021 ftcdlib 2024-01-29T19:06:27Z Abstract: Central Argentina from the Pampean flat‐slab segment to northern Patagonia (27°–41°S) represents a classic example of a broken retroarc basin with strong tectonic and climatic control on fluvial sediment transport. Combined with previous research focused on coastal sediments, this actualistic provenance study uses framework petrography and heavy‐mineral data to trace multistep dispersal of volcaniclastic detritus first eastwards across central Argentina for up to ca. 1,500km and next northwards for another 760km along the Atlantic coast. Although detritus generated in the Andes is largely derived from mesosilicic volcanic rocks of the cordillera, its compositional signatures reflect different tectono‐stratigraphic levels of the orogen uplifted along strike in response to varying subduction geometry as well as different character and crystallization condition of arc magmas through time and space. River sand, thus, changes from feldspatho‐litho‐quartzose or litho‐feldspatho‐quartzose in the north, where sedimentary detritus is more common, to mostly quartzo‐feldspatho‐lithic in the centre and to feldspatho‐lithic in the south, where volcanic detritus is dominant. The transparent‐heavy‐mineral suite changes markedly from amphibole≫clinopyroxene>orthopyroxene in the north, to amphibole≈clinopyroxene≈orthopyroxene in the centre and to orthopyroxene≥clinopyroxene≫amphibole in the south. In the presently dry climate, fluvial discharge is drastically reduced to the point that even the Desaguadero trunk river has become endorheic and orogenic detritus is dumped in the retroarc basin, reworked by winds and temporarily accumulated in dune fields. During the Quaternary, instead, much larger amounts of water were released by melting of the Cordilleran ice sheet or during pluvial events. The sediment‐laden waters of the Desaguadero and Colorado rivers then rushed from the tract of the Andes with greatest topographic and structural elevation, fostering alluvial fans inland and flowing in much larger valleys than ... Article in Journal/Newspaper Ice Sheet University of California: eScholarship Argentina Patagonia |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Physical Geography and Environmental Geoscience Earth Sciences Geochemistry Geology Geophysics |
spellingShingle |
Physical Geography and Environmental Geoscience Earth Sciences Geochemistry Geology Geophysics Garzanti, Eduardo Capaldi, Tomas Vezzoli, Giovanni Limonta, Mara Sosa, Numa Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
topic_facet |
Physical Geography and Environmental Geoscience Earth Sciences Geochemistry Geology Geophysics |
description |
Abstract: Central Argentina from the Pampean flat‐slab segment to northern Patagonia (27°–41°S) represents a classic example of a broken retroarc basin with strong tectonic and climatic control on fluvial sediment transport. Combined with previous research focused on coastal sediments, this actualistic provenance study uses framework petrography and heavy‐mineral data to trace multistep dispersal of volcaniclastic detritus first eastwards across central Argentina for up to ca. 1,500km and next northwards for another 760km along the Atlantic coast. Although detritus generated in the Andes is largely derived from mesosilicic volcanic rocks of the cordillera, its compositional signatures reflect different tectono‐stratigraphic levels of the orogen uplifted along strike in response to varying subduction geometry as well as different character and crystallization condition of arc magmas through time and space. River sand, thus, changes from feldspatho‐litho‐quartzose or litho‐feldspatho‐quartzose in the north, where sedimentary detritus is more common, to mostly quartzo‐feldspatho‐lithic in the centre and to feldspatho‐lithic in the south, where volcanic detritus is dominant. The transparent‐heavy‐mineral suite changes markedly from amphibole≫clinopyroxene>orthopyroxene in the north, to amphibole≈clinopyroxene≈orthopyroxene in the centre and to orthopyroxene≥clinopyroxene≫amphibole in the south. In the presently dry climate, fluvial discharge is drastically reduced to the point that even the Desaguadero trunk river has become endorheic and orogenic detritus is dumped in the retroarc basin, reworked by winds and temporarily accumulated in dune fields. During the Quaternary, instead, much larger amounts of water were released by melting of the Cordilleran ice sheet or during pluvial events. The sediment‐laden waters of the Desaguadero and Colorado rivers then rushed from the tract of the Andes with greatest topographic and structural elevation, fostering alluvial fans inland and flowing in much larger valleys than ... |
format |
Article in Journal/Newspaper |
author |
Garzanti, Eduardo Capaldi, Tomas Vezzoli, Giovanni Limonta, Mara Sosa, Numa |
author_facet |
Garzanti, Eduardo Capaldi, Tomas Vezzoli, Giovanni Limonta, Mara Sosa, Numa |
author_sort |
Garzanti, Eduardo |
title |
Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
title_short |
Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
title_full |
Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
title_fullStr |
Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
title_full_unstemmed |
Transcontinental retroarc sediment routing controlled by subduction geometry and climate change (Central and Southern Andes, Argentina) |
title_sort |
transcontinental retroarc sediment routing controlled by subduction geometry and climate change (central and southern andes, argentina) |
publisher |
eScholarship, University of California |
publishDate |
2021 |
url |
https://escholarship.org/uc/item/2dk3z0m4 |
op_coverage |
3406 - 3437 |
geographic |
Argentina Patagonia |
geographic_facet |
Argentina Patagonia |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Basin Research, vol 33, iss 6 |
op_relation |
qt2dk3z0m4 https://escholarship.org/uc/item/2dk3z0m4 |
op_rights |
CC-BY |
_version_ |
1792048959854739456 |