河北牛圈热泉型银(金)矿床成因

GENESIS OF NIUJUAN HOT-SPRING TYPE Ag (Au) DEPOSIT IN HEBEI PROVINCE

牛圈银(金)矿床是冀北地区近几年来新发现的重要银矿床之一.本文从硅质角砾岩成因、成矿的阶段划分、成矿物理化学条件、矿物包裹体等方面入手探讨了该矿床成因并提出了成矿模式.该矿床成矿温度稍高(220—350℃),成矿压力很低(小于260×10~5Pa),形成深度为0.42—0.86km的亚地表环境,成矿流体以低盐度(小于3.35wt%NaCl),富K^+、Cl^-、F^-、SO_4^(2-),贫Na^+、Ca^(2+),以大气水为主为特征,属典型的热泉型矿床.

This deposit is one of important Ag deposits found recently in the north part of He-bei. In this paper basing on the work of predecessors and many geologic observtions of surface, producing area, drilling cores, from the genesis of siliceous breecia, the divide of ore- foroming stages, ore forming physio-chemical conditions, inclusion etc, authors discuss the genesis of this deposit and give a metallogenic model Ore-forming tempheratures of this deposit are relatively high (220 -350℃), metallogenic press are low (less than 260×105Pa), the depth is 0. 42-0. 86km, the forming environment is the subsurface environment, the ore- forming fluid is of characters of low salinity (less than 3. 35wt% NaCl), rich in K+, Cl , F-, SO42 , poor in Na+ , Ca2+, so it belongs to a typical hot spring type deposit.