丽水—椒江凹陷西斜坡明月峰组上段碎屑锆石物源  

Detrital Zircon Provenance of Upper Mingyuefeng Formation in West Slope of Lishui-Jiaojiang Sag,the East China Sea

作　　者：付晓伟[1] 朱伟林[1,2] 陈春峰[1,3] 钟锴[2] 许长海[1] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]中国海洋石油总公司,北京100010 [3]中海石油有限公司上海分公司,上海200030

出　　处：《地球科学（中国地质大学学报）》2015年第12期1987-2001,共15页Earth Science-Journal of China University of Geosciences

基　　金：国家科技重大专项(No.2011ZX05023-003)

摘　　要：沉积物源对油气储层发育具有重要影响.为研究丽水-椒江凹陷西斜坡明月峰组上段物源的岩性组成及其分布特征,选取4口钻井4个砂岩样品进行碎屑锆石U-Pb定年,并对陆上潜在物源区岩层（体）的岩性和年龄进行统计分析.结果显示：（1）样品中碎屑锆石以岩浆锆石为主,主要的年龄区间为125~90Ma、145~125Ma及170~145Ma,还有少量变质锆石,其年龄区间为235~210Ma及2 087~1 653Ma;（2）陆上潜在物源区中以火山岩占绝对优势（173~94Ma）,局部区域可能有较大规模白垩系永康群沉积岩,而变质岩（〉210Ma）和侵入岩（107.0~87.8Ma）仅零星出露.综合分析认为：研究区东北部明月峰组上段的物源以永康群火山-沉积岩和九里坪组火山岩为主,含有少量晚白垩世侵入岩;西南部以九里坪组、西山头组火山岩及元古代区域变质岩为主,侏罗纪火山岩为辅,这一区域可能更有利于优质储层的发育.Sedimentary source has a significant impact on the development of oil and gas reservoir.To differentiate the provenance and analyze the lithological composition of the source area of the upper Mingyuefeng Formation in the west slope of Lishui-Jiaojiang sag,4 detrital zircon samples from 4 drillings were selected for U-Pb isotopic dating,and then provenance analysis was conducted according to the dating results and the age and lithology of potential source.The results suggest that detrital zircons are mainly dominated by magmatic zircons falling into the age ranges of 125-90 Ma,145-125 Ma and 170-145 Ma,and there are a small amount of metamorphic zircons aged 235-210 Ma and 2 087-1 653 Ma.In the potential source area,volcanic rocks in the age range of 168-94 Ma are in overwhelming majority,and metamorphic rocks older than 210 Ma and intrusive rocks formed in 107.0-87.8 Ma outcrop sporadically,while maybe there are sedimentary rocks of Yongkang Group concentrated locally.The comprehensive analysis shows that the provenance of the northeastern part of the study area was mainly volcanic-sedimentary rocks of Yongkang Group and volcanic of Jiuliping Formation and Late Cretaceous intrusions exposed locally.While in the southwestern part,the source rock was mainly Proterozoic metamorphic rocks and volcanic rocks from Xishantou Formation in addition to Jiuliping Formation,and a small amount of Jurassic volcanic rocks as well.,which is more favorable to the development of high-quality reservoir in the southwestern part.

关 键 词：碎屑锆石U-Pb定年 明月峰组上段 物源 丽水-椒江凹陷 沉积物 

分 类 号：P618[天文地球—矿床学]