白垩纪缺氧事件期间分子有机碳同位素偏移的二种不同机制

The Mechanism of Stable Carbon Isotope Excursion of the Individual Normal- Alkane During the Cretaceous Oceanic Anoxic Event

对我国业已发现的白垩纪大洋缺氧事件进行了对比研究。结果显示,我国河北滦平盆地高等植物叶腊碳同位素正偏,是weissert缺氧事件的陆地响应,weissert缺氧事件可能是全球性缺氧事件,而不是区域性的缺氧事件。叶腊烷烃单分子碳同位素正偏有两种不同的机制:早白垩世分子碳同位素正偏主要反映的是大气CO2水平增加;晚白垩世分子碳同位素正偏主要反映的是陆地植物类型的变化。

Comparative study was carried out on the Cretaceous OAEs discovered in China. The results show that the carbon isotope of the leaf wax from the highland of the Luanping basin, Hebei province, is positive excursion, which probably responded terrestrially to the Weissert Anoxic Event. It is suggested that the Weissert OAE is a global, not local event. There are two mechanisms responsible for carbon isotope positive excursion of leaf wax. one during the early Cretaceous reflects CO2 increase in atmosphere, and the other during the late Cretaceous was caused by terrestrial ecosystem change.