Element geochemical characteristics of the lower assemblage hydrocarbon source rocks in southeast Sichuan-central Guizhou (Chuandongnan-Qianzhong) region and its periphery areas and their implications to sedimentary environments

Abstract：This paper deals with the contents of such elements as B, V, Ni, Sr, Ba, Th and U by using the ICP-MS (Inductively Coupled Plasma-Ms Spectrometer) technique for 28 samples collected from Sinian-Silurian strata in Chuandongnan-Qianzhong region and its periphery areas. The contents of major and trace elements were determined by means of GB/T14506.28-93 and X-Ray Fluorescence Spectrometry. The corresponding relationships between the Sr/Ba, V/Ni, V/(V+Ni), Sr/Ca, Ca/Mg and Th/U values and the sedimentary environments were studied. The results show that the main sedimentary environments are bathyal, deep-sea or shallow sea stagnant environments. The difference in spatial distribution of elements reflects regional variation of the sedimentary environment.