Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina
Much of what we know about Quaternary climate has been learned from sedimentary records from the world's oceans. With the exception of the extensive studies of the Chinese loess/paleosol sequence and more recent studies of long lake records, there are few long terrestrial climate records, parti...
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ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-2644 2024-01-21T10:05:55+01:00 Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina Heil, Clifford W. King, John W. Zárate, Marcelo A. Schultz, Peter H. 2010-09-01T07:00:00Z https://digitalcommons.uri.edu/gsofacpubs/1675 https://doi.org/10.1016/j.quascirev.2010.06.024 unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/1675 doi:10.1016/j.quascirev.2010.06.024 https://doi.org/10.1016/j.quascirev.2010.06.024 Graduate School of Oceanography Faculty Publications text 2010 ftunivrhodeislan https://doi.org/10.1016/j.quascirev.2010.06.024 2023-12-25T19:09:53Z Much of what we know about Quaternary climate has been learned from sedimentary records from the world's oceans. With the exception of the extensive studies of the Chinese loess/paleosol sequence and more recent studies of long lake records, there are few long terrestrial climate records, particularly from the southern hemisphere. The loess record of Argentina provides an important opportunity to further our understanding of climate change from a terrestrial environment, but its complexity and discontinuity have led to difficulty in formulating a climatological model of depositional and pedogenic processes. In this study, we present one of the longest and most continuous loess/loessoid records from the central eastern Pampas of Argentina. Our age model is based on optically stimulated luminescent dates and a paleomagnetic reversal stratigraphy and indicates a basal age around 1.9 Ma. Within the age model uncertainties, we characterize the environmental magnetic properties associated with loess deposition and soil formation with respect to wind patterns, moisture availability, and temperature. Major changes in magnetic grain size are linked to a differential northward shift of the subtropical high-pressure cell during glacial periods. We suggest that coarser (finer) magnetic grains correspond to weaker (stronger) glacial periods when the high-pressure cell is located in a more southerly (northerly) position and the source region is more proximal (distal) to our study area. An abrupt increase in the ultrafine-grained magnetic material around 0.9 Ma is related to an increase in moisture transport from the South Atlantic driven by an increase in summer sea surface temperatures at the mid-Pleistocene transition (∼1 Ma). In addition to these grain size variations, there is a relative decrease in the amount of goethite compared to hematite beginning around 0.5 Ma, which has been related to the temperature increase observed after the mid-Brunhes Event (∼450 ka) in the EPICA ice core temperature record. A more detailed ... Text EPICA ice core University of Rhode Island: DigitalCommons@URI Argentina Quaternary Science Reviews 29 19-20 2705 2718 |
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University of Rhode Island: DigitalCommons@URI |
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ftunivrhodeislan |
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unknown |
description |
Much of what we know about Quaternary climate has been learned from sedimentary records from the world's oceans. With the exception of the extensive studies of the Chinese loess/paleosol sequence and more recent studies of long lake records, there are few long terrestrial climate records, particularly from the southern hemisphere. The loess record of Argentina provides an important opportunity to further our understanding of climate change from a terrestrial environment, but its complexity and discontinuity have led to difficulty in formulating a climatological model of depositional and pedogenic processes. In this study, we present one of the longest and most continuous loess/loessoid records from the central eastern Pampas of Argentina. Our age model is based on optically stimulated luminescent dates and a paleomagnetic reversal stratigraphy and indicates a basal age around 1.9 Ma. Within the age model uncertainties, we characterize the environmental magnetic properties associated with loess deposition and soil formation with respect to wind patterns, moisture availability, and temperature. Major changes in magnetic grain size are linked to a differential northward shift of the subtropical high-pressure cell during glacial periods. We suggest that coarser (finer) magnetic grains correspond to weaker (stronger) glacial periods when the high-pressure cell is located in a more southerly (northerly) position and the source region is more proximal (distal) to our study area. An abrupt increase in the ultrafine-grained magnetic material around 0.9 Ma is related to an increase in moisture transport from the South Atlantic driven by an increase in summer sea surface temperatures at the mid-Pleistocene transition (∼1 Ma). In addition to these grain size variations, there is a relative decrease in the amount of goethite compared to hematite beginning around 0.5 Ma, which has been related to the temperature increase observed after the mid-Brunhes Event (∼450 ka) in the EPICA ice core temperature record. A more detailed ... |
format |
Text |
author |
Heil, Clifford W. King, John W. Zárate, Marcelo A. Schultz, Peter H. |
spellingShingle |
Heil, Clifford W. King, John W. Zárate, Marcelo A. Schultz, Peter H. Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
author_facet |
Heil, Clifford W. King, John W. Zárate, Marcelo A. Schultz, Peter H. |
author_sort |
Heil, Clifford W. |
title |
Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
title_short |
Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
title_full |
Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
title_fullStr |
Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
title_full_unstemmed |
Climatic interpretation of a 1.9 Ma environmental magnetic record of loess deposition and soil formation in the central eastern Pampas of Buenos Aires, Argentina |
title_sort |
climatic interpretation of a 1.9 ma environmental magnetic record of loess deposition and soil formation in the central eastern pampas of buenos aires, argentina |
publisher |
DigitalCommons@URI |
publishDate |
2010 |
url |
https://digitalcommons.uri.edu/gsofacpubs/1675 https://doi.org/10.1016/j.quascirev.2010.06.024 |
geographic |
Argentina |
geographic_facet |
Argentina |
genre |
EPICA ice core |
genre_facet |
EPICA ice core |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/1675 doi:10.1016/j.quascirev.2010.06.024 https://doi.org/10.1016/j.quascirev.2010.06.024 |
op_doi |
https://doi.org/10.1016/j.quascirev.2010.06.024 |
container_title |
Quaternary Science Reviews |
container_volume |
29 |
container_issue |
19-20 |
container_start_page |
2705 |
op_container_end_page |
2718 |
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1788696372233371648 |