Abstract:

 The Cyclostratigraphic study has become a principal tool for refinement of the geologic time scale. Compared to the Western Tethys, the Cyclostratigraphic study on the Eastern Tethys is relatively insufficient. The precision of the study for the preQuaternary still needs to be advanced in Eastern Tethys. Cretaceous marine sediments are cropped out widely in Southern Tibet, among them the late Cretaceous in the Gongzha section of Tingri Area is rather continuous and  integrated. Based on the field observation and the measurement of the bundle thickness, we have analyzed the cycles of the orbital parameters with Fast Fourier Transport (FFT)  in this paper. And the result well matches the theoretical value as that the cycles of the precession are 4092 ka (E1)，1279 ka (E2)，and 93 ka (E5), and the cycles of the eccentricity are 512 ka (O1)，409 ka (O2)，and 389 ka (O2). In the process of power spectral analyses, a tuning treat based on the relationship between bundle and superbundle set was conducted, and those results  before and after the tuning were compared to confirm the significance of the tuning. Moreover, the variety of sedimentation rate was confirmed as well.  Generally, the sedimentation rate is in the range of 086253 cm/ka, which increased from the bottom to the top of the strata. In addition, the result of this study is compared with the published results of Cretaceous marine sediments in Western Tethys and  those from  other areas in  different ages, which indicates that in Eastern and Western Tethys, the shape, genesis and the cycles of the orbital parameters of Cretaceous marine strata are similar. And the conclusion that the orbital cycles  becoming longer are well consistent  with the theoretical value. Finally, a suggestion for further  research is given.

Key words: Key words: Southern Tibet; Tingri Area; Upper Cretaceous; Coniacian; cyclostratigraphy