Cosmogenic nuclide exposure ages and glacial history of late Quaternary Ross Sea drift in McMurdo Sound, Antarctica
Cosmogenic nuclide exposure ages and glacial history of late Quaternary Ross Sea drift in McMurdo Sound, Antarctica
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南极洲麦克默多海峡晚第四纪罗斯海漂移的宇宙成因核素暴露年龄和冰川历史
DOI：
10.1016/0012-821x(95)00006-x
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发表时间：
1995
影响因子：
5.3
通讯作者：
F. Yiou
中科院分区：
文献类型：
--
作者：
E. Brook;M. Kurz;R. P. Ackert;G. Raisbeck;F. Yiou
对南极洲麦克默多海峡沿岸罗斯海冰盖沉积的晚第四纪漂流岩片样品进行了~ 3 He、~（10）Be和~（26）Al表面暴露年龄测定。最年轻的漂移，以前认为是晚威斯康星州的年龄，有8-106 kyr（19个样本）的曝光年龄。这些结果表明，明显的“晚威斯康星州”的冰缘可能代表了一些冰盖的进步，在末次冰期。3 He暴露年龄从类似的，地层年龄较老的漂移范围从104至567千年（7个样本），并清楚地区分最年轻的漂移从较老的存款。比较罗斯海漂移石英样品中的10 Be和3 He浓度表明，只有一个样品中有显著的3 He损失，这表明宇宙成因的3 He通常保留在适当粒度的年轻南极石英样品（暴露年龄<10万年）中。在分析的五个石英样品中的两个中，26 Al相对于10 Be的显著过量排除了有意义的26 Al暴露年龄计算。这些过剩可能是由于铀和钍衰变产生的副产品成核26铝。
3He,10Be and26Al surface exposure ages were determined for rock samples from late Quaternary drift sheets deposited on the coast of McMurdo Sound, Antarctica, by the Ross Sea Ice Sheet. The youngest drift, previously believed to be Late Wisconsin in age, has exposure ages of 8–106 kyr (19 samples). These results suggest that the apparent ‘Late Wisconsin’ ice margin may represent a number of ice sheet advances during the last glacial period.3He exposure ages from analogous, stratigraphically older drift range from 104 to 567 kyr (seven samples), and clearly distinguish the youngest drift from older deposits. Comparison of10Be and3He concentrations in Ross Sea Drift quartz samples indicates significant3He loss in only one sample, suggesting that cosmogenic3He is generally retained in young Antarctic quartz samples (exposure age < 100 kyr) of appropriate grain size. In two of the five quartz samples analyzed, significant excesses of26Al relative to10Be preclude meaningful26Al exposure age calculations. These excesses may be due to nucleogenic26Al produced as a byproduct of uranium and thorium decay.