拉斯曼丘陵新生代剥露作用的裂变径迹证据

Apatite fission track thermochronology of Cenozoic exhumation in Larsemann Hills, East Antarctica

在西南极和横贯南极山脉地区，新生代裂谷和剥露作用非常普遍。但是，文献中很少记录东南极地区的新生代剥露作用。文中根据东南极普里兹湾拉斯曼丘陵地质样品的磷灰石裂变径迹年龄和热历史的模拟，认为在东南极海岸边缘存在新生代的隆升和伸展作用，其年龄为始于（49．8±12）Ma。该年龄略晚于西南极裂谷系的启动年龄（约60-50Ma）。由于差异隆升作用，在拉斯曼丘陵地区发育了更新的正断层作用——拉斯曼丘陵拆离断层的新活动，其年龄为约5．4Ma。东南极周缘新生代裂谷和伸展作用的普遍存在，是冈瓦纳裂解以来大陆分离和印度洋形成的结果。

The Cenozoic rifting and exhumation is very common in West Antarctica and Transantarctic Mountains, though it is rarely documented from East Antarctica. However, based on apatite fission track ages and thermal histories modeled for samples from Larsemann Hills, Prydz Bay, East Antarctica, we conclude that the Cenozoic uplifting and extension may have occurred in the coastal edge of East Antarctica, at 49.8±12 Ma, which is later than the onset of the rifting system （-60-50 Ma）, developed in West Antarctica. Owing to differential uplifting, a young Larsemann Hills Detachment developed at -5.4 Ma. The Cenozoic rifting and extension is a common feature around the edge of East Antarctica due to the continental separation and the formation of India Ocean since the Gondwana breakup.