Improved moraine age interpretations through explicit matching of geomorphic process models to cosmogenic nuclide measurements from single landforms
Improved moraine age interpretations through explicit matching of geomorphic process models to cosmogenic nuclide measurements from single landforms
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DOI：
10.1016/j.yqres.2011.12.002
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发表时间：
2012-03
影响因子：
2.3
通讯作者：
P. Applegate;N. Urban;K. Keller;T. Lowell;B. Laabs;M. Kelly;R. Alley
中科院分区：
文献类型：
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作者：
P. Applegate;N. Urban;K. Keller;T. Lowell;B. Laabs;M. Kelly;R. Alley
从冰碛石宇宙成因核素测量的统计分布包含以前未使用的信息冰碛年龄，他们帮助确定是否冰碛退化或继承是更重要的个人冰碛。在这里，我们提出了一种方法来提取这些信息，通过拟合地貌过程模型，以观察到的暴露年龄从单冰碛。我们还采用这种方法，94 10 Be表观暴露年龄从11个冰碛在四个已发表的研究报告。我们的模型代表10 Be积累的巨石，随着时间的推移被挖出的斜坡过程（冰碛退化），并交付巨石与预先存在的10 Be库存冰碛（继承）。目前，我们忽略了巨石侵蚀和积雪，这可能是二阶过程。给定一个高度分散的数据集，我们建立哪个模型产生更好的拟合数据，并估计年龄的冰碛从更好的模型拟合。由更好的拟合模型所代表的过程可能是造成表观年龄分散的主要原因。我们的方法应该有助于解决暴露日期的争议;我们重新审视了两项已发表的研究的结论，基于我们的模型拟合。
The statistical distributions of cosmogenic nuclide measurements from moraine boulders contain previously unused information on moraine ages, and they help determine whether moraine degradation or inheritance is more important on individual moraines. Here, we present a method for extracting this information by fitting geomorphic process models to observed exposure ages from single moraines. We also apply this method to 94 10Be apparent exposure ages from 11 moraines reported in four published studies. Our models represent 10Be accumulation in boulders that are exhumed over time by slope processes (moraine degradation), and the delivery of boulders with preexisting 10Be inventories to moraines (inheritance). For now, we neglect boulder erosion and snow cover, which are likely second-order processes. Given a highly scattered data set, we establish which model yields the better fit to the data, and estimate the age of the moraine from the better model fit. The process represented by the better-fitting model is probably responsible for most of the scatter among the apparent ages. Our methods should help resolve controversies in exposure dating; we reexamine the conclusions from two published studies based on our model fits.