冀北中生代地洼期构造与银金多金属矿床特征

冀北地区中生代地洼活动始于早侏罗世，晚侏罗世至晚自垩世达到剧烈期。经历了基性-中性，大规模酸性岩浆喷发及侵入和基性岩浆活动三个阶段。时空分布由南东逐渐向北西迁移。陆相火山盆地多为箕状盆地。区内发育三种银、金多金属矿床：（1）多因复成型；（2）隐爆角砾岩型；（3）陆相火山热液型。银金矿床均分布在箕状盆地扬起端与隆起区的过渡部位。矿体产于断裂构造内，与酸偏碱性侵入岩相伴生。

CHARACTERISTICS OF MESOZOIC DIWA TECTONICS AND ITS Ag-Au POLYMETALLIC DEPOSITS IN NORTHERN HEBEI, CHINA

The activity of Mesozoic Diwa tectonics in Northern Hebei is believed to begin in Early Jurassic with its maximum-mobility period from Upper Jurassic to Early Cretaceous, and displays three stages of magmatic evolution, which begin with basic-intermediate magmatism,so-called, succeeded by extensive acid eruptions and intrusions, and ended with basic magmatic activity. The spatial distribution and chronological order of magmatism migrate gradually from the southeast toward the northwest, and most of the continental-volcanic rock basins are dustpan-shaped ones. Three kinds of Ag-Au polymetallic deposits have been found, namely the polygenetic compound deposit, the crypto-explosive breccia deposit and the continental-volcano-hydrotherm deposit. All of the deposits are situated in the transitional portion between the uprising end of dustpan-shaped basin and the uplift region, while the ore bodies predominantly within the fractures of hostrock, accompanied by meta-alkalicacid intrusions.