华北板块北缘曹四夭超大型钼矿床成矿母岩及成矿作用

MOTHER ROCK AND MINERALIZATION OF CAOSIYAO SUPER LARGE DEPOSIT

曹四夭钼矿床成矿母岩为中生代燕山晚期侏罗纪末期(137±12)Ma少斑花岗斑岩,与全国其他十个超大型钼矿床成矿母岩—花岗斑岩微型岩株化学成分大同小异;岩石为二高二低,即高酸、高钾和低碱、低钙镁的钙碱性系列太平洋型的超浅成侵入岩,岩体侵位深度小于3 km。岩石地球化学Mo的丰度值为维诺格拉多夫世界花岗岩Mo丰度值的30.1倍,充分说明花岗斑岩体是上地幔初始岩浆正向演化至高级阶段的产物。成矿物质来源系由成矿母岩大量吞噬太古界集宁岩群黄土窑组含钼地层中深变质岩系而形成超足量储备。成矿母岩岩浆向地表运移过程中通过水岩交换转化为含矿汽水热液向围岩进行了广泛扩散、充填,从而将熔浆中的矿物质几乎全部留在了围岩中形成超大型矿床。

The mother rock of Caosiyao molybdenum deposit is granite porphyry with less spots that developed from the late Yanshan-Jurassic of Mesozoic era（ 137 ± 12） Ma,and the chemical composition is very much the same with miniature granite porphyry rock- the mother rock of the other ten large molybdenum deposits; The rocks are Pacific extra-hypabyssal intrusive rocks of magnesium calcium alkali series with the intrusive depth of less than 3 km,which are high in acid and potassium,low in alkali and calcium. Geochemical abundance value of Mo is 30. 1 times of which in the Weino Gladof World granite in the rock,which proved that granite porphyry is the product when the initial the upper mantle magma developed to the advanced stage. Source of ore-forming materials is ore-forming parent rock which is formed by plenty of mid-deep metamorphic molybdenum rocks of Archean era Jining Gr. During its migration towards the earth surface,magma of the mother rock water-rock changed into gas-hydrothermal and widely spread into the surrounding rock,so almost all the minerals of the lava were kept in the surrounding rock,and developed into super large deposits.