塔里木盆地北缘古岩溶充填物包裹体特征

FEATURES OF THE INCLUSION IN PALEO-KARST FILLINGS AT THE NORTH EDGE OF TARIM BASIN

塔里木盆地北缘露头区奥陶系碳酸盐岩中的古岩溶发育经历了从裸露到埋藏、从淡水作用到热液作用以及从湿润气候到干燥气候的变化,多期次古岩溶作用的叠加导致了充填物地球化学特征的差异性。古岩溶充填物主要有机械沉积充填物、化学淀积充填物和塌积充填物三大类。方解石和萤石包裹体的物理特征、化学相、盐度、均一温度和化学成分均具有多样性,其综合化学特性可划分为四种类型:①低温、低盐度、N aC l-H2O型;②低温、高盐度、N aC l-H2O-C aC l2型;③中温、中盐度N aC l-H2O-M gC l2型;④高温、中盐度、CO2-N aC l-H2O型。

The paleo-karst of the Ordovician carbonate rock had experienced changes from naked to buried, from fresh water to hot water, and from humid climate to arid climate in outcrop ＇area at the north edge of Tarim Basin. Thus, several times of paleo-karst were piled up and the paleo-karst were filled by different material with particular geochemical characteristics separately. There are three kinds of fillings in paleo-karst as mechanical deposition and chemical deposition as well as collapsed deposition. The physical characteristics, chemical faces, salinity, homogenization temperature, chemical component of calcite inclusion and fluorite inclusion are of diversity. The integrative chemical characteristics can be divided into 4 kinds, they are ① NaC1-HzO with low temperature and low salinity; ② NaCl-HzO-CaClz with low temperature and high salinity; ③ NaCl-H2O-MgCl2 with mid temperature and mid salinity; ④ CO2-NaCl-H2O with high temperature and mid salinity.