DOI: 10.1016/j.quascirev.2016.03.013
Scopus记录号: 2-s2.0-84962004051
论文题名: Dating buried glacier ice using cosmogenic 3He in surface clasts: Theory and application to Mullins Glacier, Antarctica
作者: Mackay S.L. ; Marchant D.R.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 140 起始页码: 75
结束页码: 100
语种: 英语
英文关键词: Antarctica
; Buried ice
; Cosmogenic-nuclides
; Debris-covered glacier
; Exposure dating
; Glacier chronology
; Helium-3
Scopus关键词: Debris
; Isotopes
; Stochastic systems
; Antarctica
; Cosmogenic nuclides
; Debris covered glaciers
; Exposure dating
; Helium-3
; Ice
; accumulation rate
; chronology
; clast
; cosmogenic radionuclide
; dating method
; entrainment
; glacial debris
; glacial erosion
; helium isotope
; ice mechanics
; theoretical study
; valley glacier
; Antarctica
; East Antarctica
; McMurdo Dry Valleys
英文摘要: We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and on top of, debris-covered glaciers, including the effects of (1) ice ablation, (2) erosion at the debris surface, and (3) stochastic geomorphic processes that impact clast movement within and on top of supraglacial debris; we then explicitly calculate the impact of each process in altering the total inventory of cosmogenic nuclides in surface clasts. Assuming basic elements of ice-dynamics and debris entrainment are known, the model results provide an estimate for the total accumulation of cosmogenic nuclides, as well as the expected range in nuclide inventories, for any clast at the surface of debris-covered glaciers. Because the values are quantified, the approach can be applied to help evaluate the robustness of existing and future cosmogenic datasets applied to these systems. As a test, we applied our model framework towards Mullins Glacier, a cold-based debris-covered alpine glacier in the Dry Valleys of Antarctica. Our simulated values for cosmogenic-nuclide inventories compare well with those previously measured from fifteen surface cobbles along Mullins Glacier (3He), both in terms of expected ranges and absolute values, and suggest that our model framework adequately incorporates most of the complicating factors that impact cosmogenic datasets for cold-based, debris-covered glaciers. Relating these cosmogenic-nuclide inventories to ice ages, the results show that ice within Mullins Glacier increases non-linearly, ranging from 12 ka to ~220 ka in areas of active flow, to »1.6 Ma in areas of slow-moving-to-stagnant ice. © 2016 Elsevier Ltd. 资助项目: Funding for this research was provided by NSF Graduate Research Fellowship awarded to S.L. Mackay and NSF Polar Programs grants NSF ANT-0944702, NSF ANT-0739700, and NSF ANT-1043706 awarded to D.R. Marchant. Logistical support for this project in Antarctica was provided by the U.S. National Science Foundation through the U.S. Antarctic Program. Measurements of cosmogenic nuclides reported in this study were completed by Joerg Schaefer at the cosmogenic-nuclide lab at the Lamont Doherty Earth Observatory and by William Phillips and Gary Landis at the USGS noble gas laboratory, Denver Federal Center.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59607
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Earth and Environment, Boston University, Boston, MA, United States
Recommended Citation:
Mackay S.L.,Marchant D.R.. Dating buried glacier ice using cosmogenic 3He in surface clasts: Theory and application to Mullins Glacier, Antarctica[J]. Quaternary Science Reviews,2016-01-01,140