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36Cl Chronologies and ELA reconstructions from the northern boundary of the South American Arid Diagonal

Thornton, Rachel M
http://orcid.org/0000-0002-9711-1094
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1552399052152741

Abstract Details

2019, MS, University of Cincinnati, Arts and Sciences: Geology.
This study focused on glaciation in the South American Arid Diagonal (AD) climatic feature which intersects in the Andes mountain range at approximately 24°S. This NE-SW-trending zone of hyper-aridity separates the Atlantic-sourced Easterly moisture belt from the Pacific-sourced Westerly precipitation in the central Andes. We present new geomorphological maps of the landforms, particularly of glacial moraines across two mountain ranges within the Western Cordillera of the central Andes. Additionally, new 36Cl chronologies using surface exposure dating were produced from two sites near the northern boundary of the modern AD. One site is located in the Cordillera del Tatio at ~21°S (Tatio field site), the other is the southernmost valley in a stratovolcano chain called the Cordon de Puntas Negras at ~24°S (SPN field site). Paleo-ELAs were reconstructed utilizing a two-dimensional numerical model to simulate glaciers over a 90m digital elevation model of the upstream catchment. We find that four glacial stages were present at both field sites sampled. Glacial stabilizations from the El Tatio field site, once assumed Lateglacial in age are on the order of 10-20 thousand years older than previously published. Tatio ages ranged from ~25 ka to as early as MIS 5. We also found that dated glacial stages from El Tatio and the Puntas Negras are not synchronous with lake highstands on the Altiplano, but projected ages of the younger glacial stages indicate both sites were glaciated during the Tauca phase. Regional comparison indicated the possibility of glacial occupation of the Tatio site into the Lateglacial during the Coipasa phase (12 ka) after rapid deglaciation of the SPN field site. Regional ELA comparisons supported the trend of moisture loss from the NE to SW portions of the climatic AD feature.
Dylan Ward, Ph.D. (Committee Chair)
Aaron Diefendorf, Ph.D. (Committee Member)
Thomas Lowell, Ph.D. (Committee Member)
109 p.
Geology
glacial geomorphology; geology; paleoclimate; cosmogenic; arid diagonal; arid Andes

Recommended Citations

Citations

  • Thornton, R. M. (2019). 36Cl Chronologies and ELA reconstructions from the northern boundary of the South American Arid Diagonal [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1552399052152741

    APA Style (7th edition)

  • Thornton, Rachel. 36Cl Chronologies and ELA reconstructions from the northern boundary of the South American Arid Diagonal. 2019. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1552399052152741.

    MLA Style (8th edition)

  • Thornton, Rachel. "36Cl Chronologies and ELA reconstructions from the northern boundary of the South American Arid Diagonal." Master's thesis, University of Cincinnati, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1552399052152741

    Chicago Manual of Style (17th edition)

ucin1552399052152741
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This open access ETD is published by University of Cincinnati and OhioLINK.