新疆塔西南区海相白垩系—第三系界线的地球化学异常

ABNORMAL GEOCHEMICAL CHARACTERISTICS OF THE BOUNDARY BETWEEN THE MARINE CRETACEOUSTERTIARY IN THE SOUTHWESTERN TARIM BASIN

新疆塔里木盆地西南地区海相白垩系—第三系的界线粘土层发现于依格孜牙组和吐依洛克组之间。这一层具有相当复杂的元素组合 ,存在诸多元素异常。它不仅是一条生物界线 ,而且是一条地球化学界线。这一异常事件层代表了白垩纪与第三纪之交的突变事件 ,具有全球的一致性和等时性 ,因而具有自然界线性质。

The marine K T boundary clay have been found by authors between the Yigzya Formation and Tuylouk Formation,not found between the Tuylouk Formation and Artashi Formation in the southwestern Tarim Basin.There are a very complex element assemblage and abnormal contents of a number of elements,particularly iridium,osmium and REE.It is not only a boundary of organism extinction,but also a boundary of abnormal geochemistry.This abnormal event bed represents a catastrophic event of the Cretaceous Tertiary with global consistency and simultaneity.Therefore, it should be a natural boundary.