The Extent of Early Versus Late Wisconsin Glaciation: A Test Using Cosmogenic 36C1 Dating

宇宙成因氯-36累积年代测定法是一种新的地质年代学方法，它测量的是岩石暴露在地球表面宇宙射线下的时间，而不是它成为地球化学封闭系统的时间。因此，该方法可以用于确定地貌的形成年代，例如冰川冰碛，这些地形很难或不可能用传统方法确定年代。该奖项支持在四个地点(1)测量莫纳克亚山（Mauna Kea）的样品，(2)怀俄明州的风河山脉（Wind River Range），(3)西北地区的班克斯岛（Banks Island）通过宇宙成因36Cl积累进行的冰川年代学研究。加拿大，以及(4)北极高地的另一个地点。这些地点将提供北半球的纬度样带，以检验先前在夏威夷和内华达山脉观察到的时间模式是由于巧合的局部异常还是真正的全球气候影响。积极结果的一个潜在含义是，大陆尺度冰盖的增长可能更多地是对内部动力的响应，而不是全球气候强迫。

Cosmogenic chlorine-36 buildup dating is a new geochronological method that measures how long a rock has been exposed to cosmic rays on the earth's surface, rather than the time since it became a geochemically closed system. The method can thus be used to date the construction of landforms, such as glacial moraines, that are difficult or impossible to date using conventional methods. This award supports glacial chronology investigations by cosmogenic 36Cl buildup at four locations (1) measurements on samples from Mauna Kea, (2) the Wind River Range, Wyoming, (3) Banks Island, NWT. Canada, and (4) one other site in the High Arctic. These sites will provide a latitudinal transect of the northern hemisphere to test whether the chronological pattern previously observed at Hawaii and the Sierra Nevada was due to coincidental local anomalies or to truly global climate effects. One potential implication of a positive result would be that the growth of continental-scale ice caps may be more a response to internal dynamics than global climate forcing.