藏南岗巴地区上白垩统海相碳酸盐岩碳稳定同位素研究

Carbon stable isotopes of the Upper Cretaceous marine carbonate rocks in the Gamba region, southern Xizang

关键词:  碳稳定同位素  白垩纪  碳酸盐岩  岗巴  藏南

Key words:  carbon stable isotope  Cretaceous  carbonate rock  Gamba  southern Xizang

摘要:

本文对藏南岗巴地区上白垩统海相碳酸盐岩的碳稳定同位素组成特征及变化趋势进行了研究,对比分析了藏南其它地区及欧洲同时代地层,认为岗巴地层的碳稳定同位素的记录很好地响应了白垩纪期间全球性的缺氧事件。通过对岗巴地区岩石地层学及区域环境的分析说明,全球性的海平面升降及板块运动造成了大洋溶解氧含量的波动是碳稳定同位素δ¹³C值偏移的根本原因。

Abstract:

The carbon stable isotopic compositions and variations are examined for the Upper Cretaceous marine carbonate rocks in the Gamba region, and the stratigraphic correlation is made for the study area and other coeval marine strata in southern Xizang and Europe. The carbon stable isotopic records in the Gamba strata have well responsed to the global anoxic events during the Cretaceous. The lithostratigraphic and environmental analysis shows that the changes of oceanic dissolved oxygen contents caused by global sea-level changes and plate movement are a cause or effect of the deviation of δ¹³C values.