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出露于突尼斯卡夫附近的白垩纪与第三纪界线剖面是至今所知最完整的界线层序。它由厚约1米含浮游有孔虫 POa,b 带的黑色粘土和灰色的界线粘土,2米厚的 Pla 带(Globigerna eugubina)粘土质页岩和4米厚 Pla 带(G.taurica)的页岩和泥灰岩所组成。底栖有孔虫生物的定量分析表明出现于斜坡上部至陆架外部环境的最晚白垩纪沉积在 K/R 界线上变浅为外至中陆架深度,至 Plb 时期进一步变浅为中陆架深度。在 K/R 界线附近底栖有孔虫的分异度有一个明显的衰减,约有50%的生物种消失。在界线以上(POa,b—Pla)开始的3米沉积物中生物分异度平均值停留在37%以下,而且繁殖力极低。此时期残留和繁盛的有孔虫主要是能容忍低氧的表栖种和内栖种。界线(Plb 带)以上约4米处适应低氧生物的明显衰减及以浅水种陆架生物的出现标志了第二次回归,回到了较高含氧量和繁殖力的环境。虽然 K/R 界线事件的环境影响可以通过底生栖物来确定,但是最终的原因仍难以断定。 K/R 界线以后生物的重要变化和较长的恢复期是难以用一种单一的碰撞假说所能解释得了的。
The Cretaceous and Tertiary boundary profiles exposed near Kraft in Tunisia are the most complete boundary lineages ever known. It consists of a black clay of about 1 m with planktonic foraminifera POa, b, and gray boundary line clays, a 2 m thick layer of Globigerna eugubina clay shale and a 4 m thick layer of G. taurica Shale and marl formed. Quantitative analysis of benthic foraminifera showed that the latest Cretaceous sediments appearing in the upper part of the slope to the outer shelf environment were shallow in the K / R boundary to the outer-to-middle shelf depth and further to the mid-shelf depth in the Plb period. There was a significant attenuation of the diversity of benthic foraminifera near the K / R boundary, with about 50% of the species disappearing. The average value of the biological diversity in the 3-meter sediment above the boundary (POa, b-Pla) stayed below 37% and the fertility was very low. The remaining and thriving foraminifera during this period are mainly benthic and endangered species that tolerate hypoxia. The apparent attenuation of the adaptation to hypoxia at a distance of about 4 m above the boundary line (Plb band) and the emergence of shelled creatures in shallow water marked a second regression back to a higher oxygen and fertility environment. Although the environmental impact of K / R boundary events can be determined by subsistence, the ultimate cause remains uncertain. Important changes in biology after the K / R boundary and longer recovery periods are difficult to interpret with a single collision hypothesis.