Controls on subaerial erosion rates in Antarctica
Controls on subaerial erosion rates in Antarctica
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DOI：
10.1016/j.epsl.2018.08.018
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发表时间：
2018-11
影响因子：
5.3
通讯作者：
S. Marrero;A. Hein;M. Naylor;Mikael Attal;Richard A. Shanks;Kate Winter;J. Woodward;S. Dunning
中科院分区：
文献类型：
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作者：
S. Marrero;A. Hein;M. Naylor;Mikael Attal;Richard A. Shanks;Kate Winter;J. Woodward;S. Dunning
侵蚀速率提供了对景观发展和风化的化学和物理过程的相对重要性的见解。最小的化学风化使南极洲成为比较碳酸盐岩和其他岩性物理风化的理想地点。在这里，我们报告了南极洲碳酸盐岩的首次宇宙成因核素侵蚀速率。在Ellsworth山脉最南端采集的碳酸盐样品反映了a36Cl侵蚀速率为0.22±0.02 mm/ka。这一侵蚀速率与其他报道的南极侵蚀速率一致，但低于世界上其他干旱地区的36cl侵蚀速率。这些结果与对28项宇宙核素侵蚀率研究（bbb2000测量）进行的全大陆范围的再分析相结合，这些研究包括许多岩石类型和多种宇宙核素。通过综合研究中宇宙核素衍生的侵蚀速率，更大的趋势提供了对影响南极洲陆上侵蚀速率的因素（如岩性、冰川历史和磨料的可用性）的深入了解。对汇编数据集的统计分析显示了基于岩性的差异，砂岩的侵蚀速率范围最大。汇编的数据还显示，在像干谷这样具有大量潜在沉积物供应的地区，侵蚀率更高。从巨石上采集的样品比从基岩上采集的样品产生更低的侵蚀速率，这可能是由于物理过程对巨石和基岩的影响不同，以及冰川历史的结合，这可能会影响明显的宇宙成因核素产生的侵蚀速率。
Erosion rates offer insight on landscape development and the relative importance of chemical and physical processes of weathering. Minimal chemical weathering makes Antarctica an ideal location in which to compare the physical weathering of carbonate rocks to other lithologies. Here we report the first cosmogenic nuclide-derived erosion rates for carbonate rocks in Antarctica. Carbonate samples collected in the southernmost Ellsworth Mountains reflect a36Cl erosion rate of 0.22 ± 0.02 mm/ka. This erosion rate is consistent with other reported Antarctic erosion rates, but is lower than36Cl erosion rates derived from other arid regions in the world. These results are integrated with a continent-wide reanalysis of 28 cosmogenic nuclide erosion rate studies (>200 measurements), which comprise numerous rock types and multiple cosmogenic nuclides. By combining cosmogenic nuclide-derived erosion rates across studies, the larger trends provide insight into factors (e.g. lithology, glacial history, and availability of abrasive material) affecting subaerial erosion rates in Antarctica. Statistical analysis of the compiled data set shows differences based on lithology, with sandstone having the largest range of erosion rates. The compiled data also reveals higher erosion rates in areas with a large potential sediment supply, like the Dry Valleys. Samples collected from boulders yield lower erosion rates than those collected from bedrock, likely due to a combination of physical processes that affect boulders and bedrock differently, and glacial history, which can affect the apparent cosmogenic-nuclide derived erosion rate.