贵州关岭动物群产出地层的地球化学特征及其对物源和沉积环境的指示意义

对贵州关岭晚三叠统法郎组瓦窑段底部的毛凹剖面系统地采集了105个岩石样品，测定了样品中的36种化学元素含量。作者对它们进行元素富集因子（EF）分析、R型聚类分析、R型因子分析、元素和氧化物的含量与Al2O3的含量比值以及δCe在剖面中垂向变化的分析，讨论了元素含量变化的制约因素、沉积物的来源、古海洋氧化还原条件的变化、关岭动物群的埋藏环境。结果表明：研究的5.2 ~17.7 m段剖面地层以陆源碎屑和生物碎屑混合沉积为主，沉积物来源于陆壳，而不是火山和热液的来源，其沉积的氧化还原条件多次反复变化；元素的含量变化主要受陆源物质、氧化还原条件、生物碎屑以及成岩作用控制；从元素地层学角度将所研究的剖面段从下到上可划分为4层，第1层至第4层元素对比值曲线呈现出平缓波动-频繁波动-平缓波动的周期性变化特征；该段偏还原的环境对海百合及海生爬行动物化石的保存和埋藏起了良好的作用。

Geochemistry characteristics and implications on provenance and sedimentary environments of Guanling Fauna bearing strata,Guizhou Province

Altogether 105 rock samples are collected from the Maowa section, the bottom part of the Wayao Member of Falang Formation of Late Triassic in Guanling County, Guizhou Province, and contents of 36 elements of the rock samples are measured by ICP (Inductively Coupled Plasma Emission Spectroscopy). Based on the measured data, the authors analyze the enrichment factors (EF), R type cluster analysis and R type factors of the elements, and chronological changes of the ratio of elements to Al2O3, the ratio of oxides to Al2O3 and the value of δCe, then discuss the factors controlling the changes of element contents, and present an interpretation about the sedimentary provenance, paleoredox condition and burial environment of Guanling Fauna. As a conclusion, the sediments within the studied interval in 5.2 ~17.7 m in the Maowa section are mainly composed of terrigenous and biogenic substances, which are deriving from continent crust rather than volcanic material or thermal water. During this course, paleo-oceanic redox conditions changed repeatedly. The changes of element contents are controlled by terrigenous material, redox conditions, biogenic material and diagenesis. The 5.2 ~17.7 m interval of the section can be divided into four beds in terms of elementary stratigraphy. The ratio of elements and oxides to Al2O3 changes frequently from the first bed (bottom part of the interval) to the fourth bed (top part of the interval), showing a periodicity from slight to strong fluctuation. By correlating the paleoredox conditions with the occurrences of fossils, the authors suggest the formation and preservation of the crinoids and marine reptiles fossils benefit from anoxic conditions.