北祁连铜矿成矿规律及找矿方向

MINEROGENIC REGULARITIES AND EXPLORATION GUIDES OF COPPER DEPOSITS OF NORTH QILIAN

北祁连是我国西北部的一个重要火山岩带和有色金属成矿带。本文划分出三条火山岩亚带和四个喷发旋回。并以白银厂、红沟、浪力克和桦树沟四个铜、多金属矿床的典型地质特征为基础归纳成矿规律:①矿床赋存具有时控层控特点;②矿床分布有成带性、分段性特征;③火山构造和火山机构是重要的控矿条件;④火山沉积型矿床就位于火山喷发旋回顶部;⑤火山热液型矿床赋存于玄武安山岩的断裂、片理化带中;⑥原生矿化分带规律明显;⑦热液蚀变带、氧化带发育;⑧矿床类型主要有四种;⑨铜、铁共生规律。进而从四大成矿带中划分出十一个矿带,认为火山沉积型、火山热液型、斑岩型和热液型应作为今后找矿的主要类型,并指出了重点找矿地区。

North Qilian is an important volcanic rock zone and nonferrous minerogenie zone in the northwest of China.The zone is divided into three volcanic rock subzones and four eruption cycles.According to the typical geological features offour copper—polymetal ore deposits,that is,Baiyinchang,Honggou,Langlike and Huashugou,minerogenic regularities havebeen summarized as follows:(1)Ore deposits are formed with the characters of timebound and stratabound;(2)Ore depositsare zonately and sectionally distributed;(3)Volcanic tectonics and apparatus are significant eonditions of controllingmineralization;(4)Volcanogenic—sedimentary ore deposits are situated at the top of volcanic eruption cycle;(5)Volcanogenic—hydrothermal ore deposits occur in the faulting and schistosity zone of basaltic andesite;(6)Origional mineralization possesses clear zoning;(7)Hydrothermal alteration and oxidized zones are developed;(8)There are four predominant types of oredeposits;(9)Copper and iron coexist.Further eleven mineral subzones have been identified in four minerogenie zones.Voleanogenie sedimentary,volcanogenic hydrothermal,porphyry and thermal types should be taken as the main prospectingtypes in the future.At last important exploration areas have been pointed out.