A New Pleistocene Glacial Chronology from Patagonia

在巴塔哥尼亚冰原过去扩张期间形成的冰川沉积提供了南半球冰川作用和气候变化的连续记录。这些中纬度冰川运动的精确年代学对于确定南北半球的气候变化是否同步是必要的，这是理解冰期触发机制(S)的关键因素。普遍的假设是，安第斯山脉的冰川进程与北美冰川同步，这是基于有限的年代学信息。该奖项支持一项研究，该研究旨在获得布宜诺斯艾利斯拉戈冰川冰川新的高精度年代学，该年表记录了巴塔哥尼亚冰原的第四纪波动。冰雹保存极为完好，并有很好的圈定年代学，这是由于共存的年代确定的熔岩流，但没有直接的年代学。这项研究将使用3He、21Ne、10Be和36Cl在不同的冰河脊上获得巨石样品的表面暴露日期。这项研究将结合现场采集样本的努力和实验室确定冰雹年龄的努力。

Glacial deposits formed during past expansions of the Patagonian ice fields provide a continuous record of southern hemisphere glaciation and climate change. A precise chronology of these mid-latitude glacial advances is necessary to determine if climate changes were simultaneous in the northern and southern hemispheres, which is a key factor in understanding the triggering mechanism(s) for the ice ages. The common assumption, that glacial advances in the Andes were synchronous with North American glaciations, is based on limited chronological information. This award supports a study to obtain a new high precision chronology of glacial moraines at Lago Buenos Aires, which record Quaternary fluctuations in the Patagonian ice fields. The moraines are extremely well-preserved and have excellent bracketing chronology, due to coexisting Ar-dated lava flows, but there is no direct chronology. This study will obtain surface exposure dates, using 3He, 21Ne, 10Be and 36Cl on boulder samples from the distinct moraine ridges. This research will combine field efforts for sample collection and a laboratory effort to determine the ages of the moraines.