中国陆相盆地油页岩形成环境与成矿机制

近10年来,油页岩勘探开发和成矿理论研究取得重要进展.作者在前期研究和系统调研的基础上,概要总结了中国陆相油页岩的形成环境和成矿机制.总体表明,油页岩易形成于相对较高的O2和低CO2浓度的大气背景下,具有4个主要成矿期次;盆地内构造和古气候协同控制油页岩的矿床规模,补偿环境易于形成深水油页岩,而过补偿环境沉积浅水油页岩...

Formation environment and mineralization mechanism of oil shale in continental basins of China

In the past ten years,great progress has been made in the exploration,development and formation theory of oil shale. Based on previous research and systematic investigation,we summarized the formation environment and mineralization mechanism of continental oil shale in China. In general,the oil shale preferably forms in the atmospheric background with relatively high O2 and low CO2 concentration,with four main mineralization mechanisms. In the basins,the tectonic and paleoclimate control the deposit scale of oil shale,resulting in deep-water oil shale formed in balance filled environment,and shallow water oil shale in the over filled environment. The deep water oil shale was deposited in the semi-deep and deep lake environment,where the lake bottom is in the state of hypoxia to anoxia. The biological productivity is the key factor to control the quality of oil shale,and the duration of favorable conditions and the range of low oxygen area determine the scale of oil shale deposit. Shallow water oil shale was deposited in limnetic environment. Lakes with eutrophication and turbid algae are the premises of shallow water oil shale deposition.The restoration of lake itself and paleoclimate regulation result in thin thickness and strong horizontal and vertical heterogeneity of oil shale. Some geological events promoted oil shale deposition and mineralization.For example,anoxia,volcanism,hydrothermal and marine transgression events help to improve bioproductivity and form anoxic environment. Based on the analyses of oil shale forming environment,the mineralization mechanism of deep water and shallow water oil shale is summarized. Combined with the regional tectonic evolution of the China continent,the temporal and spatial distribution of oil shale in China is mainly controlled by the influence of Paleo-Asia,Tethys and Circum-Pacific tectonic domains.