酒西盆地首例湖相"白烟型"喷流岩——热水沉积白云岩的发现及其意义

酒西盆地青西凹陷下沟组中广泛发育的纹层状“白云质泥岩”和“泥岩白云岩”，以其富含铁白云石，钠长石和方沸石等特殊的矿物组分和优越的油气地质条件，引起众多石油地质工作者的重视。以往的研究成果中，认为此两类岩石的成因均与火山作用有关。在该项研究中，依据此两类岩石的空间展布规律与北东向基底断裂的拉张活动密切相关，岩石的矿物组合和结构，构造特征主要显示热水沉积性质，并含有大量重晶石，地开石和再现微量闪锌矿，黄铜矿和方铅矿等特征的热液矿物，认为此两类岩石均属于湖相“白烟型”喷流岩，识别出各以铁白云石、钠长石，重晶石，方沸石和地开石为主的6种热水矿物组合类型，在此基础上，划分出脉状充填型，水爆角砾型，盆地沉积型和区域扩散型4种成因类型的喷流岩，文中首次提出喷流型热水沉积铁白云岩成因类型，探讨了此类白云岩在油气藏勘探与开发工程中的研究意义。

DISCOVERY OF THE FIRST EXAMPLE OF "WHITE SMOKE TYPE" OF EXHALATIVE ROCK (HYDROTHERMAL SEDIMENTARY DOLOSTONE) IN JIUXI BASIN AND ITS SIGNIFICANCE

A number of petroleum geological workers take it seriously that extensively distributed lacustrine laminted dolomitic mudstone and muddy dolomite contains rich special mineral component, such as ferrodolomite , albite and analcite, ect. and superior geological condition of petroleum and natural gas in the Xiagou Formation from Qingxi sag of Jiuxi basin. The past studies indicate that the cause of the formation of two types of rocks is the same. They resulted from volcanism. According to the evidences that the spreading pattern in space of the two types of rocks is controlled by taking part activity of basement fault and that the mineral assemblage including large quantity of barite and dickite and micro quantity of pseudogalena, chalcopyrite and galena, the texture and structure features of the two types of rocks mainly indicate the hydrothermal sedimentary nature. The authors present that the genesis of two types of rocks belongs to the "white smoke type" of lacustrine exhalative rock which is divided into four types of the sedimentary ways, i.e., filling lode rock type, water bursting breccia type, basin depositing type and region diffusing type and six main types of the assemblage of hydrothermal mineral mainly including ferrodolomite , albite, barite, analcite, and dickite. In the same time, they suggest that the exhalative rock is a new genetic type of hydrothermal sedimentary dolostone for the first time and discuss the implication of exhalative rock in the exploring and developing oil and gas fields.