Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier
Apatite (U-Th)/He thermochronology has the potential to reconstruct records of erosional exhumation that are critical to understanding interactions between climate, tectonics, and the cryosphere at high latitudes on million-year timescales. However this approach is often hindered by the problem of i...
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ftiupui:oai:scholarworks.iupui.edu:1805/39617 2024-04-28T08:02:43+00:00 Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier He, John Thomson, Stuart N. Reiners, Peter W. Hemming, Sidney R. Licht, Kathy J. Earth Sciences, School of Science 2021 application/pdf https://hdl.handle.net/1805/39617 en_US eng Elsevier 10.1016/j.epsl.2021.117009 Earth and Planetary Science Letters He J, Thomson SN, Reiners PW, Hemming SR, Licht KJ. Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier. Earth and Planetary Science Letters. 2021;567:117009. doi:10.1016/j.epsl.2021.117009 https://hdl.handle.net/1805/39617 Publisher Policy Author Apatite helium thermochronology East Antarctic ice sheet Glacial erosion Overdispersion Subglacial landscape Article 2021 ftiupui https://doi.org/10.1016/j.epsl.2021.117009 2024-04-03T14:08:30Z Apatite (U-Th)/He thermochronology has the potential to reconstruct records of erosional exhumation that are critical to understanding interactions between climate, tectonics, and the cryosphere at high latitudes on million-year timescales. However this approach is often hindered by the problem of intrasample single-grain date dispersion. Here we present an extensive new apatite (U-Th)/He dataset (n = 361) from the central Transantarctic Mountains of East Antarctica between 160°E to 170°W and 84 to 86°S, and show that apparently uninterpretable data in most samples are a reflection of inadequate sampling of skewed date distributions. We outline a workflow for interpreting such dispersed data and demonstrate that geologically meaningful age interpretations are possible in the case of rapidly cooled samples, despite the wide array of potential causes for date dispersion. We show that for samples and compilations with a large number of single-grain analyses (n > ∼25), the youngest probability distribution peak represents the most likely time of fast cooling through the apatite (U-Th)/He closure temperature. When fewer grains are analyzed, the youngest peak is represented best by the minimum date or first quartile date, depending on sample size. Using this workflow, we show that since the latest Eocene, up to 8.8 km of exhumation occurred to incise the deepest point of the Beardmore Glacier trough. Rapid incision began at c. 37-34 Ma (at the latest by 34±3 Ma), coinciding with or slightly preceding the initiation of Antarctic glaciation at the Eocene-Oligocene transition, and contributed to at least 2.6 km of exhumation within the first 3-6 million years, at an apparent exhumation rate of no less than 0.4 mm/a. Article in Journal/Newspaper Antarc* Antarctic Antarctica Beardmore Glacier East Antarctica Ice Sheet Indiana University - Purdue University Indianapolis: IUPUI Scholar Works Earth and Planetary Science Letters 567 117009 |
institution |
Open Polar |
collection |
Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
op_collection_id |
ftiupui |
language |
English |
topic |
Apatite helium thermochronology East Antarctic ice sheet Glacial erosion Overdispersion Subglacial landscape |
spellingShingle |
Apatite helium thermochronology East Antarctic ice sheet Glacial erosion Overdispersion Subglacial landscape He, John Thomson, Stuart N. Reiners, Peter W. Hemming, Sidney R. Licht, Kathy J. Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
topic_facet |
Apatite helium thermochronology East Antarctic ice sheet Glacial erosion Overdispersion Subglacial landscape |
description |
Apatite (U-Th)/He thermochronology has the potential to reconstruct records of erosional exhumation that are critical to understanding interactions between climate, tectonics, and the cryosphere at high latitudes on million-year timescales. However this approach is often hindered by the problem of intrasample single-grain date dispersion. Here we present an extensive new apatite (U-Th)/He dataset (n = 361) from the central Transantarctic Mountains of East Antarctica between 160°E to 170°W and 84 to 86°S, and show that apparently uninterpretable data in most samples are a reflection of inadequate sampling of skewed date distributions. We outline a workflow for interpreting such dispersed data and demonstrate that geologically meaningful age interpretations are possible in the case of rapidly cooled samples, despite the wide array of potential causes for date dispersion. We show that for samples and compilations with a large number of single-grain analyses (n > ∼25), the youngest probability distribution peak represents the most likely time of fast cooling through the apatite (U-Th)/He closure temperature. When fewer grains are analyzed, the youngest peak is represented best by the minimum date or first quartile date, depending on sample size. Using this workflow, we show that since the latest Eocene, up to 8.8 km of exhumation occurred to incise the deepest point of the Beardmore Glacier trough. Rapid incision began at c. 37-34 Ma (at the latest by 34±3 Ma), coinciding with or slightly preceding the initiation of Antarctic glaciation at the Eocene-Oligocene transition, and contributed to at least 2.6 km of exhumation within the first 3-6 million years, at an apparent exhumation rate of no less than 0.4 mm/a. |
author2 |
Earth Sciences, School of Science |
format |
Article in Journal/Newspaper |
author |
He, John Thomson, Stuart N. Reiners, Peter W. Hemming, Sidney R. Licht, Kathy J. |
author_facet |
He, John Thomson, Stuart N. Reiners, Peter W. Hemming, Sidney R. Licht, Kathy J. |
author_sort |
He, John |
title |
Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
title_short |
Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
title_full |
Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
title_fullStr |
Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
title_full_unstemmed |
Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier |
title_sort |
rapid erosion of the central transantarctic mountains at the eocene-oligocene transition: evidence from skewed (u-th)/he date distributions near beardmore glacier |
publisher |
Elsevier |
publishDate |
2021 |
url |
https://hdl.handle.net/1805/39617 |
genre |
Antarc* Antarctic Antarctica Beardmore Glacier East Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Beardmore Glacier East Antarctica Ice Sheet |
op_source |
Author |
op_relation |
10.1016/j.epsl.2021.117009 Earth and Planetary Science Letters He J, Thomson SN, Reiners PW, Hemming SR, Licht KJ. Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier. Earth and Planetary Science Letters. 2021;567:117009. doi:10.1016/j.epsl.2021.117009 https://hdl.handle.net/1805/39617 |
op_rights |
Publisher Policy |
op_doi |
https://doi.org/10.1016/j.epsl.2021.117009 |
container_title |
Earth and Planetary Science Letters |
container_volume |
567 |
container_start_page |
117009 |
_version_ |
1797574006451208192 |