青海省苏海图金矿床地质特征及控矿因素

Geological characteristics and ore-controlling factors of Suhaitu Gold Deposit,Qinghai Province

苏海图金矿床位于东昆仑成矿带中部东昆仑南坡俯冲碰撞杂岩带内,该区为青海省多金属成矿密集区,金、铜、锑等矿床(点)密布,成矿地质条件优越。在综合分析区域地质概况和矿床地质特征的基础上,探讨了控矿因素和矿床成因。研究表明,金矿(化)体主要赋存于奥陶—志留系纳赤台群变余长石石英砂岩和构造角砾岩中,且严格受近EW向、NW向断裂及蚀变破碎带控制;沿次级断裂或裂隙侵入的花岗斑岩脉及石英脉为寻找金矿有利地质体;黄铁矿化、褐铁矿化和硅化等围岩蚀变与金成矿关系密切,是重要的找矿标志。矿床成因类型为热液型,工业类型为蚀变岩型和石英脉型。

Suhaitu Gold Deposit is located in subduction-collision complex zone on the southern slopes that sit in the central part of the East Kunlun metallogenic belt.This area was polymetallic mineralization concentration area in Qinghai Province,where gold,copper and antimony deposits(points)are densely distributed and the ore-forming geological conditions are superior.Based on comprehensive analysis of the regional geological situation and geological features,the ore-controlling factors and the deposit genesis were analyzed.The results show that the gold ore bodies are mainly located in blastospathic quartz sandstone and tectonic breccia of Ordovician-Silurian Nakchitai Group,and strictly controlled by near EW-trending and NW-trending fractures and alteration zones;the intrusive granite veins and quartz veins along secondary faults or fissures were favorable for gold deposits;the surrounding rock alteration,such as pyritization,ferritization and silicification,were closely related to gold mineralization and therefore important prospecting indicators.The genetic type of the deposit belongs to hydrothermal deposit and the industrial type is tectonic altered rock type and quartz vein type.