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Latitudinal variation in glacial erosion rates from Patagonia and the Antarctic Peninsula (46°S–65°S)

2016; Geological Society of America; Volume: 128; Issue: 5-6 Linguagem: Inglês

10.1130/b31321.1

1943-2674

Rodrigo Fernández, John B. Anderson, Julia S. Wellner, Rebecca Minzoni, B. Hallet, R. Tyler Smith,

Polar Research and Ecology

Research Article| May 01, 2016 Latitudinal variation in glacial erosion rates from Patagonia and the Antarctic Peninsula (46°S–65°S) Rodrigo A. Fernandez; Rodrigo A. Fernandez † 1Institute for Geophysics, University of Texas, 10100 Burnet Road, Austin, Texas 78758, USA †r.f@ig.utexas.edu Search for other works by this author on: GSW Google Scholar John B. Anderson; John B. Anderson 2Earth Science Department, Rice University, 6100 Main Street, MS126, Houston, Texas 77005, USA Search for other works by this author on: GSW Google Scholar Julia S. Wellner; Julia S. Wellner 3Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, USA Search for other works by this author on: GSW Google Scholar Rebecca L. Totten; Rebecca L. Totten 2Earth Science Department, Rice University, 6100 Main Street, MS126, Houston, Texas 77005, USA Search for other works by this author on: GSW Google Scholar Bernard Hallet; Bernard Hallet 4Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar R. Tyler Smith R. Tyler Smith 5BHP Billiton, 171 Collins Street, Melbourne, Victoria 3000, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Rodrigo A. Fernandez † 1Institute for Geophysics, University of Texas, 10100 Burnet Road, Austin, Texas 78758, USA John B. Anderson 2Earth Science Department, Rice University, 6100 Main Street, MS126, Houston, Texas 77005, USA Julia S. Wellner 3Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, USA Rebecca L. Totten 2Earth Science Department, Rice University, 6100 Main Street, MS126, Houston, Texas 77005, USA Bernard Hallet 4Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA R. Tyler Smith 5BHP Billiton, 171 Collins Street, Melbourne, Victoria 3000, Australia †r.f@ig.utexas.edu Publisher: Geological Society of America Received: 19 Mar 2015 Revision Received: 24 Sep 2015 Accepted: 23 Nov 2015 First Online: 08 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2016 Geological Society of America GSA Bulletin (2016) 128 (5-6): 1000–1023. https://doi.org/10.1130/B31321.1 Article history Received: 19 Mar 2015 Revision Received: 24 Sep 2015 Accepted: 23 Nov 2015 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Rodrigo A. Fernandez, John B. Anderson, Julia S. Wellner, Rebecca L. Totten, Bernard Hallet, R. Tyler Smith; Latitudinal variation in glacial erosion rates from Patagonia and the Antarctic Peninsula (46°S–65°S). GSA Bulletin 2016;; 128 (5-6): 1000–1023. doi: https://doi.org/10.1130/B31321.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract We use extensive sedimentary and marine geophysical data to derive sediment volume–based millennial time-scale glacial erosion rates (Ē) from glacially influenced fjords and bays across a broad latitudinal transect, from central Patagonia (46°S) to the Antarctic Peninsula (65°S), and to determine how glacial erosion rates change with increasing latitude and decreasing atmospheric temperatures. We also calculate million-year time-scale erosion rates for the western Antarctic Peninsula cordillera and inner continental shelf from seismic stratigraphic analysis of the continental margin. These results are complemented by erosion rates derived from existing thermochronology data sets (apatite fission-track and apatite [U-Th]/He) for both Patagonia and the Antarctic Peninsula regions.Despite considerable regional variability, our results show a clear trend of decreasing Ē with increasing latitude. Millennial Ē values span two orders of magnitude, from 0.02 mm/yr for Illiad glacier on Anvers Island, Antarctica (∼64.5°S), to 0.83 mm/yr for San Rafael glacier in northern Patagonia (∼46.5°S). Regional averages are three times higher for the Patagonian areas than the Antarctic Peninsula areas. This trend is interpreted to result from a general decrease in temperature and water availability at the ice-bedrock interface. For the Antarctic Peninsula study sites, erosion rates are highly clustered around 0.1 mm/yr, with the exception of Maxwell Bay, for which the Ē value is 0.36 mm/yr. In Patagonia, erosion rates are more variable than in the Antarctic Peninsula, with Ē ranging between 0.14 mm/yr (Europa glacier area) and 0.83 mm/yr (San Rafael glacier area). This regional variability in Ē is interpreted as due to differences in hypsometry and bedrock resistance to erosion.Million-year time-scale Ē values derived from thermochronology ages also decrease with latitude, with maximum values decreasing from ∼0.9–1.1 mm/yr north of 46°S to ∼0.1–0.2 mm/yr south of 48°S in Patagonia, and reaching ∼0.2–0.3 mm/yr in the Antarctic Peninsula. The sediment-based million-year time-scale Ē estimates for the western Antarctic Peninsula cordillera indicate that glacial erosion rates increased by 25%–30% after 5.3 Ma, from ∼0.09 mm/yr (5.3–9.5 Ma) to ∼0.11–0.12 mm/yr (<5.3 Ma). For Patagonia, the decrease in long-term erosion rates south of ∼46°S is interpreted to result from relatively long periods of slow glacial erosion associated with the ice masses having been colder (subpolar) on the southern Patagonian cordillera, and having eroded at rates comparable to those we obtained for the Antarctic Peninsula. These long-term erosion rates are 1–2 orders of magnitude lower than estimates based on recent sediment yields, highlighting the transient nature of high-sediment-flux events. However, our sediment volume–derived millennial time-scale Ē closely approximates the maximum values of tectonic time-scale Ē values derived from thermochronology ages. Our combined millennial and million-year time-scale glacial erosion data quantify the significant decrease in rates of glacially driven denudation at geological (tectonic) and millennial time scales with increasing latitude from Patagonia to the Antarctic Peninsula, highlighting the influence of climate on mountain denudation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.