Tectonic uplift history of the Yitong Basin since the Oligocene,Northeast China:Evidence from apatite fission track ages and geological relationship

摘要

The Yitong Basin is an oilbearing basin with unique characteristics in Northeast China. On the basis of apatite fission track ages and geological relationship, the tectonic uplift history of the Yitong Basin since the Oligo-cene was discussed. Based on apatite fission track analysis of five samples from the Luxiang and Chaluhe fault depressions and basin modeling study, it can be concluded that since the Oligocene (36.6 Ma) in the Yitong Basin, the Chaluhe fault depression has undergone two episodes of uplift during 24.9-19.1 Ma and 6.9-4.9 Ma. And the Luxiang fault depression also had undergone two episodes of uplift during 30-27.8 Ma and 22.6-11.1 Ma. Moreover, the average apparent exhumation rates for the Chaluhe fault depression and Luxiang fault depression, could be calculated to be 70.34 and 60.33 m/Ma since 21.8 Ma and 18.9 Ma, respectively. The results of thermochronological analysis can also be supported by the evidence from geological relationships such as geodynamics, volcanic activity, and stratigraphic division and correlation.