| Autor: |
Gao, Junbo, Yang, Ruidong, Tao, Ping, Cheng, Wei, Wei, Huairui |
| Předmět: |
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| Zdroj: |
Chinese Journal of Geochemistry; Sep2013, Vol. 32 Issue 4, p321-325, 5p |
| Abstrakt: |
The evolution of the global sulfur isotope curve was plotted based on the δ 34S values of evaporates resultant from oceanic evaporation. In the long period of geological history the δ 34S values showed obvious peaks for three times during the process of ancient oceans’ sulfur isotope evolution, namely the Early Cambrian (+30‰), the Late Devonian (+25‰) and the Permian-Triassic transition interval (+17‰), but the causes of the abnormal rise of sulfur isotopic values during the geological period are still in question. In this paper, 18 samples collected from a large Devonian barite deposit from Zhenning County were analyzed to determine their δ 34S values, revealing that the 18 samples have very high δ 34S values (δ 34S=41.88‰–+68.39‰), with an average close to 56.30‰, which are higher than the isotopic values of contemporary sulfates (+17‰–+25‰). A comparative analysis was conducted of the emerging of high δ 34S barite deposits (from Cambrian and Devonian) and the δ 34S variation curves of the ancient oceans. The results indicate that the time when the obvious peaks of δ 34S values appeared and the time of massive sedimentation of high δ 34S barite deposits are very close to each other, which, in our opinion, is not a coincidence. There may exist some correlations between the sulfur isotope evolution of ancient oceans during the diverse periods of geological history and the massive sedimentation of high δ 34S barite deposits. Therefore, it is inferred that perhaps it was the massive sedimentation of high δ 34S barites that caused the sharp rise of δ 34S values in a short period of time. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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