砂宝斯金矿区多矿物脉特征及其对砂岩的改造

Characteristics and the Influence on Wall Rock of Multiple——Mineral Veins in Shabaosi Gold Deposit

砂宝斯矿区的成矿围岩为长石石英砂岩,砂岩被多期次的石英脉、方解石脉和高岭石脉所穿切,这些多矿物脉是热液流体运移的结果。矿物脉形成过程中对围岩进行了热改造,使砂岩发生了压溶作用、胶结作用和溶蚀作用,形成了蚀变砂岩。由于流体酸碱性和温压的变化,孔隙水介质的性质由酸性向碱性转变,在酸性成岩环境下形成的蚀变高岭石、伊利石将转变成绿泥石、绢云母等。绢云母的大量出现,石英次生加大和自生粘土矿物的形成均是热液流体活动的产物。

Feldspar quartz sandstone, the wall rock of gold orebodies in Shabaosi deposit, is often cut by various veins such as quartz, calcite and kaolinite. These veins are the result of removing thermal fluid. Feldspar quartz sandstone can be reworked to form altered stone during the formation of these veins, and compaction, dissolution and cementation occured simultaneously. Due to the variety of fluid acidic--base and temperature--pressure, pore fluid changed from acidic to alkalic environment. During this period, altered kaolinite and illite in the acidic environment will changeover to be chlorite and sericite, etc. A lot of sericite, sencondary enlargement of the quartz, authigenic clay are all caused by the thermal fluid.