四川盆地东北部二叠系长兴组礁岩中的放射轴状纤维状胶结物  

Radiaxial fibrous cement of reefal framestone of Permian Changxing Formation in northeastern Sichuan Basin

作　　者：黄思静[1,2] 王春梅[1,2] 佟宏鹏[1,2] 黄可可[1,2] 

机构地区：[1]成都理工大学"油气藏地质及开发工程国家重点实验室" [2]成都理工大学沉积地质研究院

出　　处：《岩性油气藏》2010年第3期9-15,共7页Lithologic Reservoirs

基　　金：国家自然科学基金(编号:40839908)资助

摘　　要：四川盆地东北部晚二叠世孤立碳酸盐台地边缘生物礁岩中发育的放射轴状纤维状胶结物(RFC),虽然已完全白云石化,但仍然具有双晶面弯曲(波状消光)且远端收敛的特征,高锶、高钠和暗阴极发光等反映海源流体环境的地球化学特征以及层状胶结物和内部沉积物等RFC的其它特征。RFC的原始矿物是海水环境中沉淀的高镁方解石,其存在说明四川盆地东北部二叠系长兴组海绵礁发育于陡峭的台地边缘,并具有千万年尺度的长期与海水接触的地质条件。RFC中内部沉积物的存在说明胶结过程持续时间很长并有短时间的间断,虽然这种间断与短时间的海平面下降有关,但就RFC发育的整个千万年尺度的时间来说,海平面是上升的,生物礁的建造速度与海平面上升幅度基本一致。Radiaxial fibrous cement（RFC） developed in reefal framestone of Late Permian isolated carbonate platform in northeastern Sichuan Basin.Although the RFChas completely dolomitized,itstill presents the typical characteristics of curved twin planes,undulose extinction and distal convergence,and also has the geochemical characteristics of high strontium and high natrium content and dark cathodoluminescence,showing marine fluid environment,as well as laminated cement and internal deposition in cement.High magnesian calcite deposited in marine environment is the primary mineral of RFC,indicating that spongy reefs of Permian Changxing Formation in northeastern Sichuan Basin developed in a steep platform margin,and contacted with seawater for tens of millions of years.The internal deposition in RFC indicates that the process of cementation lasted very long and breaked in a short period.This depositional break is relevant to sealevel drop in a short period,butas tothe RFC development process,the sealevel is rising,and the rate of organic reefs is in accordant with the rising amplitude of sealevel.

关 键 词：台地边缘礁 RFC 海水胶结物 长兴组 四川盆地东北部 

分 类 号：TE122.2[石油与天然气工程—油气勘探]