A 12 000 year radiocarbon date of deglaciation from the Continental Divide of northwestern Montana
A 12 000 year radiocarbon date of deglaciation from the Continental Divide of northwestern Montana
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蒙大拿州西北部大陆分水岭 12000 年冰川消融的放射性碳测年
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
P. Carrara
中科院分区：
文献类型：
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作者：
P. Carrara
在皮内代尔(威斯康星州晚期)冰川运动期间，从山上冰场流出的冰川向东流经蒙大拿州西北部的马里亚斯山口，穿过大陆分水岭。这个出口冰川是两个梅迪奇冰川的主要来源，两个梅迪奇冰川是一个大型的山前冰川，从山前向东延伸约55 公里进入平原。在马里亚斯山口附近的一段湖泊沉积物中，从冰川峰底和圣海伦斯山下的一块木屑中获得了12 194 ± 145 BP(AA-9530)的加速器质谱仪放射性碳年龄。这一放射性碳年龄为马里亚斯山口地区提供了一个最小的冰川消融日期，比之前的估计早了大约800年。此外，放射性碳测年表明，两药冰川不再由其主要来源供应，如果它仍然存在，也只是作为一个垂死、停滞的冰块存在。
During the Pinedale (Late Wisconsinan) glaciation, an outlet glacier from a mountain ice field flowed eastward across the Continental Divide through Marias Pass in northwestern Montana. This outlet glacier was the major source of the Two Medicine glacier, a large piedmont glacier that extended from the mountain front east about 55 km onto the plains. An accelerator mass spectrometry radiocarbon age of 12 194 ± 145 BP (AA-9530) was obtained from a wood fragment, underlying a Glacier Peak tephra and a Mount Saint Helens set J tephra in a section of lake sediments, near Marias Pass. This radiocarbon age provides a minimum date of deglaciation for the Marias Pass area that is about 800 years older than a previous estimate. Furthermore, the radiocarbon age indicates that the Two Medicine glacier was no longer being supplied by its major source and if it still existed was only as a dying, stagnant ice mass.