沉积学报2012，Vol.30Issue(4)：761-769,9.
黔南坳陷下寒武统烃源岩地球化学特征及成因
Geochemical Characteristics and Origins of the Lower Cambrian Source Rocks from the Southern Guizhou Depression,SW China
摘要
Abstract
The Lower Cambrian source rock samples from three typical profiles in the southern Guizhou Depression were analyzed for TOC values,δ13C values,Tmax temperatures,potential generation,and biomarkers using Rock-Eval,GC,GC-MS to elucidate the geochemical characteristics and its origin.The results show that the Lower Cambrian black shales in the southern Guizhou Depression are regional marine excellent source rocks with depth of 50-150m,and have the TOC values of 0.13%-15.40%,average 3.31%（n=169）;the kerogens of the source rocks have the δ13C values of-35.79‰——29.88‰,average-32.85‰（n=35）,and the kerogen macerals are mainly sapropelinites;the values of the marine vitrinite reflectance of the kerogens are 1.95%-3.96%,and the values of the equivalent vitrinite reflectance are 2.02%-3.47%;the distribution shapes of the n-alkanes are mainly single peak,and the maximum peak carbon are mainly C22,the C30 hopane and C27ααα20R regular sterane are abundant,the regular steranes are mainly C27C29C28,the Pr/Ph values are 0.27-0.62,the source rocks have relative high abundance of gammacerane and dibenzothiophene,the OEP values are 0.82-1.11,C31 homohopane 22S/（22S＋22R） have values of 0.56-0.63,average 0.59;the source rocks are generally characterized by enrichment in light REE,Ba,Mo,V and U element,relative strong negative anomaly of Ce element,relative strong positive anomaly of Eu element and relative high ratio of U/Th.In summary,the Lower Cambrian marine source rocks in the southern Guizhou Depression have a wide distribution with a thickness of from tens of meters to hundreds of meters,the source rocks have high TOC values,are excellent for organic matter type,and have a post-maturity.It is the product which is jointly controlled by high paleo-productivity and anoxic environment.It can provide abundant organic matter for hydrocarbon generation in the southern Guizhou Depression.关键词
烃源岩评价/海相烃源岩/生物标志化合物/生产力/缺氧环境/牛蹄塘组/黔南坳陷Key words
source rock evaluation/marine source rock/biomarker/productivity/anoxic environment/Niutitang Formation/southern Guizhou Depression分类
能源科技引用本文复制引用
贺训云,姚根顺,蔡春芳,沈安江,吴敬武,黄羚,陈子炓..黔南坳陷下寒武统烃源岩地球化学特征及成因[J].沉积学报,2012,30(4):761-769,9.基金项目
全国油气资源战略选区调查与评价项目 （）
国家科技重大专项（编号：2008ZX05004-002）资助 （）
