新疆石油地质

新疆石油地质 ›› 2006, Vol. 27 ›› Issue (2): 146-149.

• 油气勘探 • 上一篇    下一篇

塔中地区西北部奥陶系白云岩(化) 成因分析

钱一雄1,2, 尤东华2   

  1. 1.中国石油大学资源与环境学院, 北京 102249;
    2.中国石化石油勘探开发科学研究院西部分院, 乌鲁木齐 830011
  • 收稿日期:2005-05-24 修回日期:2005-05-24 出版日期:2006-04-01 发布日期:2020-10-30
  • 作者简介:钱一雄(1962-) , 男, 江苏苏州人, 教授级高级工程师, 在读博士研究生, 地球化学,(Tel) 0991-3662050(E-mail) qyx9167@vip.sina.com.

An Analysis of Ordovician Dolomitisation Origin in Northwestern Tazhong Area

QIAN Yi-xiong1,2, YOU Dong-hua2   

  1. 1. Institute of Resources and Environment, China University of Petroleum, Beijing 102249, China;
    2. West Branch, Research Institute of Petroleum Exploration and Development, Sinopec, Urumqi, Xinjiang 830011, China
  • Received:2005-05-24 Revised:2005-05-24 Online:2006-04-01 Published:2020-10-30

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摘要： 对塔中西北部中1 井区奥陶系白云岩矿物学-岩石学及地球化学特征研究表明, 其共有泥-粉晶白云石、泥晶白云石、斑状白云石、与缝合线有关的交代白云石、异型白云石和糖粒状白云石等多种结构类型, 广泛发育镶嵌状、亮边雾心结构、交代残余、生长环带等埋藏成岩作用结构, 主要反映不同介质下的埋藏成岩环境; 具有相对低的锶(Sr为161×10-6) 和相对高的钠(Na 为0.09%); δ13C 平均为-2.0‰; δ18O 平均为-6.8‰, 进一步表明其既属于埋藏白云岩范畴,又具有准同生期成岩特点。流体包裹体研究表明, 埋藏作用中的白云石化流体是温度为115~130℃和170~210℃、盐度为5%~7%、8%~9%和12%~13%的中高温、高盐度的卤水。综合认为, 它主要为成岩白云岩, 但也存在在潮上及潮间带上与灰岩共生的准同生期白云岩。

关键词: 塔里木盆地, 白云岩, 成因, 成岩作用, 地球化学, 包裹体

Abstract: The study of mineralogical-petrologic and geochemical characteristics of Ordovician dolomite in Wellblock Zhong-1 in northwestern Tazhong area shows that it is composed of dolosiltite, dolomicritein, spotty dolomite, replacement dolomite related with stylolite, baroque dolomite and sugar granular dolomite (dolorudite), characterized by mosaic, mist-core with bright rim, metasomatic and zonal diagenetic textures, reflecting buried diagenetic environment under these different media, with relatively low Sr of 161 ×10-6, relatively high Na of 0.09%; δ13C of -2.0‰ and δ18O of -6.8‰ in average, which indicate its nature of both buried dolomite and quasicogenetic diagenesis. The fluid inclusion study shows that the buried and dolomitized fluid is bittern with mid-high temperature of 115~130℃ and 170~210℃ and high salinity of 5%~7%, 8%~9% and 12%~13%. It is concluded that such a dolomite belongs to diagenetic dolomite and associated quasi-cogenetic dolomite in supratidal and intertidal zones.

Key words: Tarim basin, dolomite, origin, diagenesis, geochemistry, inclusion

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