Fission track analysis and thermotectonic history of the main borehole of the Chinese Continental Scientific Drilling project

摘要: Abstract The Chinese Continental Scientific Drilling (CCSD) project, part of the International Program (ICDP), has completed drilling a 5158 m hole in eastern Dabie–Sulu ultrahigh-pressure metamorphic belt. This study reports on an apatite fission track analysis core samples from 0 to 4000 m depth CCSD main (CCSD-MH). We determined ages 38 different depths. range between 98.6 ± 17.0 and 3.2 ± 1.3 Ma, showing general decreasing trend with depth, 87.1 ± 11.2 Ma at surface 3.2 ± 1.3 Ma 3899 m depth. As first approximation, average uplift rate ~ 35 m/Ma is calculated for period 90–30 Ma. within borehole shows some fluctuations, indicates movements along major faults. It inferred that highest-level normal fault occurs ~ 350 m, recording vertical displacement ~ 400 m. Movement another prominent ~ 2150 m occurred subsequent ~ 25 Ma. Three reverse faults occur about 2450, 3050 3250 m Testing geological constrains against data set indicated agreement reheating area during late Cretaceous Eocene, followed by cooling ~ 80 °C Eocene low until reached their present-day position Donghai area.