摘要
In Yuanba area of the northeastern Sichuan Basin,vitrinite reflectance and (U-Th)/He dating analyses of apatite and zircon in chip samples from the Xujiahe (T3x)-Jiading (K1j) formations were carried out. From Paleogene to Neogene (0.2~36.4 Ma), the Mesozoic strata in Yuanba area went through a severe cooling uplift and denudation with the denudation rate of 109.9 m/Ma. In K1j and the overlying strata, the maximum denudation thickness was about 4 000 m. The dynamic thermal evolution history in the study area was illustrated systematically as followed. In Mesozoic, the maximum palaeogeothermal of strata was 170~190 ℃. As strata upraise, palaeogeothermal decreased. From 36 to 176 Ma, palaeogeothermal was 95~170 ℃. From 0 to 36 Ma, the present geotemperature is below 95 ℃.