We now know the age of the glaciation accurately from radiometric dating of the carbon-14 in logs buried in the drift.
我们现在通过测量掩埋在漂流物中木头放射性的碳-14元素，以精确地确定冰川作用的时期。
2
Radiocarbon dating of fossils taken from caves on islands along southeastern Alaska's coast suggest that at least a portion of the area was remaining ice-free during the last ice age.