| Author's Name: Ren Ying, Zhong Dakang, Gao Chonglong, Yang Xueqi, Li Haiyang,
Yang Qiang, Liu Yunlong, Wang Yu |
| Institution: China University of Petroleum(Beijing) |
| Abstract: |
| Based on the study of field sedimentary characteristics and the observation of indoor thin sections, carbon and oxygen isotopes were tested for 22 samples of Lower Cambrian Longwangmiao carbonate rock from eastern Sichuan Basin. After the validity of these samples was fully demonstrated, the characteristics of carbon and oxygen isotopes were analyzed and the paleoclimate and paleo-ocean environments during the Longwangmiao sedimentary period were discussed. The δ13C values of carbonate distributed between-1.533‰ and 2.619‰ with an average of 0.046‰, while the δ18O values varied from -9.916‰ to -3.58‰ and-7.746‰ on average. The overall variation trends of carbon and oxygen isotope in this area are basically the same as the other areas in Yangtze platform. It is shown that eastern Sichuan Basin was marine environment during the Longwangmiao sedimentary period, and the salinity of seawater had a decrease at first, followed by an increase and second decrease at the end. Seawater temperature mainly distributed between 20℃ and 30℃, being a warm or hot subtropical climate. Under the influence of depositional environments, such as slowly fluctuated decline of sea level, the exposure of shelf and biologic depopulation, the δ13C values had the evolutionary trend of negative drift. Those indices reflect that the lowest seawater depth and the highest salinity were present in the middle period of Longwangmiao Formation deposition, which was the best time favorable for development of dolostone. |
| Keywords: Lower Cambrian; Longwangmiao Fm.; Carbon isotope; Oxygen isotope; Paleo-ocean environment; Sichuan Basin |
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投稿时间：
2015-10-08 |
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