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。
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 dolosihite, dolomicritein, spotty dolomite, replacement dolomite related with stylolite, baroque dolomite and sugar granular dolomite （dolorndite）, 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%; δ^13C of -2.0‰ and δ^18O 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.
出处
《新疆石油地质》
CAS
CSCD
北大核心
2006年第2期146-150,共5页
Xinjiang Petroleum Geology
