GEOLOGICAL EVENT ACROSS THE BOUNDARY OF THE LATEST PALEOCENE TO EARLIEST EOCENE IN TINGRI, SOUTHERN TIBET

The marine early|middle Early Paleogene in the northern Tethys Himalayas was found in southern Tibet in mid 1980s (Hao and Wan, 1985), and the bio|, litho|, and chrono| stratigraphy were patterned by then (Hao and Wan, 1985; Willems et al., 1993, 1996). It seems that there is not an abrupt boundary between the Paleocene and Eocene (P/E) because they are composed of carbonate rocks. This similarity is widespread in the world. They are well examined in many ocean DSDP and ODP logs in similar continuous sediments. But in fact, it is sure that there is a geologic event between the Paleocene and Eocene around the world. Foraminifer extinction, stable isotope record, clay mineral changes, etc. verify the geologic event existence at the latest Paleocene. Unlike the K/T boundary, there is at present little direct or indirect evidence of such catastrophes coincident with the transition (Zachos et al., 1993). This work first shows that there could be also a geologic event across the boundary of latest Paleocene to earliest Eocene exposed on land, certainly in China territory.The P/E transitional sediment is exposed and remeasured at Gongzha, northwestern flank of the Zhepure Shan Syncline, west to Tingri. Here the P/E transitional stratum is approximately equivalent to the upper Member IV and the entire Member V (Willems et al., 1993, 1996). The exact boundary between the Paleocene and Eocene, i.e. between the Unit 16 and Unit 17, is determined by benthic foraminiferal zonations. The fossil zone Alveolina beginning at Unit 17 is just above the boundary that is partly different from Willems et al (1993, 1996).