Detrital zircon LA-ICP-MS U-Pb age of the Late Permian Linxi Formation in Horqin Right Wing Middle Banner-Tuquan area of Inner Mongolia and its geological significance.

A set of thick layer rocks, which lack fossils and suffered from contact metamorphism, have been recognized as Early Permian Suolun Formation, Late Permian Linxi Formation and Lower Cambrian strata in Horqin Right Wing Middle Banner-Tuquan area, Inner Mongolia. Age data of 52 detrital zircons obtained from LA-ICP-MS dating show that the detrital zircon U-Pb ages could be divided into two parts: the young ages varying from 255Ma to 354Ma with the peak age of 263Ma and 283Ma, and the other ages concentrated in the range of 413-529Ma with the peak age of 485Ma. The authors also obtained some old data such as 625Ma, 965Ma, 1372Ma, 1707Ma, and 1727Ma. Compared with the age of 242Ma of the granite which was intruded into the strata, the age of 263Ma suggests that the strata could be assigned to the Late Permian Linxi Formation. The data of age characteristics that represent the provenance of the strata and the collision of the Siberian and North China plates in Late Permian are also discussed in this paper. In addition, the stratigraphic age gives evidence to support the assumption that the Late Permian Linxi Formation occurred beneath Tuquan Basin as “second low resistivity layer”.