Apatite fission track study of Cenozoic uplifting and exhumation of Wutai Mountain, China

Wutai Mountain is the highest mountain in Taihang Mountain-chain, which is one of the important boundaries of the three grade physiognomy in China. The study on its uplifting history is important in confirming the forming age of the three grade physiognomy. We collected a series of rock samples along two sections, one is from Beitai peak of Wutai Mountain northwards and downwards to its root, and the other is from the maximal altitude of Changchengling Region, Fuping county, eastwards and downwards to its root. Then we selected 16 samples to make apatite fission track study. The histogram of length distribution of the confined fission track shows that the samples in Wutai Mountain had been cooling monotonously since the end of late Cretaceous, i.e. Wutai Mountain had been uplifting since then. The analysis of the fission track age-height plot Of samples, the inverse modeling of thermal history and Excel data fitting reveal that the uplifting of Wutai Mountain was episodic since the end of late Cretaceous, which included three rapid uplifting periods, 74 similar to 58 Ma, 46 similar to 31 Ma and about 15 Ma. The uplifting of Wutai Mountain since the end of late Cretaceous correspond with the uplifting of other regions in Taihang Mountain-chain and its peripheral mountains, such as Zhangxuan Uplift and Taishan Mountain etc. in time,indicating Cenozoic uplifting of Wutai Mountain is a part of regional tectonic evolution.