ESR dating of the evolution of the Shuanghu basin in the northern Tibetan Plateau

The Shuanghu basin is a NE-trending rift basin bounded by NE-striking norma l faults and NW-striking shear-extensional faults of the northern Tibetan P lateau. Four samples from calcite veins in marginal faults and one sample f rom mudstone (S-3) were collected for dating the evolution of the Shuanghu basin by using the ESR spectrograph of EXM-type. Ages were calculated accor ding to the close-equilibrium model on the basis of the measured ESR signal spectra of samples, providing good chronological information. It is known from the ESR dating that the extensional faulting and rifting of the Shuang hu area began at 4.92 Ma B.P., followed by regional folding in 3.56-1.36 Ma , NW-striking faulting in 0.60 Ma and normal faulting in 0.024 Ma in the Sh uanghu basin.