Ammonite biostratigraphy and organic carbon isotope chemostratigraphy of the early Aptian oceanic anoxic event (OAE 1a) in the Tethyan Himalaya of southern Tibet
| Autor: | K. Stoykova, Hanwei Yao, Vyara Idakieva, Xi Chen, Huiming Liang, Chengshan Wang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Total organic carbon
Ammonite 010506 paleontology Aptian Paleontology Biostratigraphy 010502 geochemistry & geophysics Oceanography 01 natural sciences Anoxic waters language.human_language Diagenesis Isotopes of carbon Chemostratigraphy language Ecology Evolution Behavior and Systematics Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Palaeogeography, Palaeoclimatology, Palaeoecology. 485:531-542 |
| ISSN: | 0031-0182 |
| DOI: | 10.1016/j.palaeo.2017.07.010 |
| Popis: | The early Aptian oceanic anoxic event (OAE 1a) is well known in the western Tethys, the North Atlantic and the Pacific Ocean, but has not been reported in the eastern Tethys to date. In this paper, we present bulk organic carbon isotope data and ammonite biostratigraphy of a lower Aptian succession from the Gucuo area (southern Tibet). These findings document the occurrence of the OAE 1a for the first time from the eastern Tethys. The studied sequence can be attributed to the D. forbesi and D. deshayesi ammonite zones of the lower Aptian. The δ 13 C org data can be correlated with published early Aptian carbon isotope records from the western Tethys and the Pacific. A distinctive negative carbon isotope excursion of 2.4‰ in the upper part of the section corresponds to segment C3 of the OAE 1a, and the following positive excursion correlates to segment C4. The absolute values of the carbon isotope ratio in the Gucuo area are higher than those of known sections in the western Tethys and equatorial Pacific. We suggest that diagenetic alteration is the major cause of the higher absolute values in the Gucuo area. |
| Databáze: | OpenAIRE |
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