湖相白云质喷流岩物质组分对比与成因机理研究

Since the first discovery of Xiagou Formation lacustrine dolomitic exhalative rocks in Qingxi Sag of Jiuquan Basin, similar rocks have been found in many basins and formations, such as Fengcheng Formation in Urho area of northwest Junggar Basin, Lucaogou Formation in Santanghu region of eastern Junggar Basin, Shahejie Formation in Liaodong Bay of Bohai Bay Basin and Lower Cretaceous in Erlian Basin of Inner Mongolia. Our goal is to contrast the compositions of lacustrine dolomitic exhalative rocks from different basins and different formations. On the basis of outcrops and drilling cores, according to the comprehensive petrological, mineralogical, geochemical features and fluid inclusions, and combined with regional tectonic setting and thermal history, we will clear the compositional and geochemical differences of lacustrine dolomitic exhalative rocks from different basins and different formations, the nature and source of hydrothermal fluids of various types of lacustrine dolomitic exhalative rocks. We will explore the formation conditions of lacustrine dolomitic exhalative rocks from different basins and different formations relationships, and the relationship with the endogenic geological processes and their spatial and temporal evolution, including tectonic setting, the nature of the basins, volcanic eruption and hydrothermal activities. Then the the sedimentary models and genesis of lacustrine dolomitic exhalative rocks from different tectonic settings and basins will be established and analoged, which will provide new integrated sedimentary models and genesis for the lacustrine primary hydrothermal exhalative dolostones.

自从酒泉盆地青西凹陷下沟组发现首例湖相白云质喷流岩以来,于准噶尔盆地西北缘乌尔禾地区风城组，噶尔盆地东缘三塘湖地区芦草沟组，内蒙古二连盆地下白垩统，渤海湾盆地辽东湾凹陷沙河街组等多个盆地和多个层位都发现类似的湖相白云质喷流岩。以不同盆地和层位的湖相白云质喷流岩物质组分对比与成因分析为目标，地表露头和钻井岩心为对象，综合岩石学、矿物学，元素地球化学及流体包裹体特征分析成果，结合区域构造背景和热演化史、深入分析不同盆地和层位的湖相白云质喷流岩物质组分及其独特的地球化学特征异同性，查明各类型湖相白云质喷流岩热流体性质、来源，了解不同盆地和层位的湖相白云质喷流岩的形成条件，及其与地球内动力作用之间的关系和时空演化规律，包括构造背景、盆地性质、火山喷发、热液喷流活动等，建立和类比不同构造背景和盆地性质的湖相白云质喷流岩沉积模式，为湖相原生热液喷流沉积成因的白云岩形成机制提供新的综合型模式和成因解释。