贵州中三叠世盘县动物群产出地层剖面样品元素地球化学数据因子分析及其环境演化意义

Factor analyses and environmental evolution implications of element geochemistry data for the section bearing the Middle Triassic Panxian Fauna in Guizhou Province

应用地质统计学方法研究剖面沉积物化学组分的含量变化规律和相互关系,以了解剖面沉积物及其化学组分的影响因素和剖面地层的古环境演化。从R型和Q型因子分析结果得出,剖面沉积物及其化学组分含量主要受陆源物质影响,其次受火山源物质的影响,成岩作用及生物源物质也发挥了一定的作用。剖面的古环境演化以陆源物质、火山源物质和生物源物质混合沉积为主,其间至少经历了7次火山喷发。短期频繁的火山喷发及大量的火山喷发物可能严重影响该时期剖面位置的爬行动物及其他生物的生活环境,这可能是它们在这段时间大量死亡的重要原因之一。

Geological statistical methods are used to analyze the changing regularities of the chemical components of the sediments from the studied section, to investigate the relationships among the elements, and finally to reveal the factors affecting the sediments and their chemical components, as well as the palaeoenvironmental evolution of the strata. According to the R-type and Q-type factor analyses, the sediments and their chemical components of the section are mainly affected by terrigenous materials. The volcanic material is the second most important influencing factor, while diagenesis and biogenic materials only play a limited role. The palaeoenvironmental evolution was a mixture of the above four types of sediments with different origins, and during the depositional process, volcanic eruption happened at least seven times. These volcanic events and volcanic materials might seriously affect the living environment of marine reptiles and other animals, and thus, they may be one of the most important causes which led to their massive deaths during this period.