青海锡铁山铅锌矿床断层沟矿段成矿预测  

Geological characteristics and metallogenetic prediction of Duancenggou target,Xitieshan Pb-Zn deposit,Qinghai

作　　者：辛天贵 祝新友[2] 

机构地区：[1]西部矿业有限责任公司,西宁810000 [2]北京矿产地质研究院,北京100012

出　　处：《矿产勘查》2013年第4期373-381,共9页Mineral Exploration

基　　金：全国危机矿山接替资源找矿项目(编号:200663063)资助

摘　　要：青海锡铁山铅锌矿床发育较完整的喷流沉积(SEDEX)成矿系统,断层沟位于该系统东南端。在锡铁山矿区赋矿的滩间山群a-b岩组向东南方向一直连续延伸至断层沟地区,岩性和含矿特点基本稳定。断层沟一带也含有大量的喷流沉积岩,包括大理岩和顺层分布的石英钠长石岩层。其中,大理岩与锡铁山矿区大理岩成因一致,皆属喷流卤水与海水相互作用的产物,更多地表现为喷流沉积系统远端特征。层状石英钠长岩也代表喷流沉积系统相对远端的喷流沉积活动,是很多SEDEX矿床的外围常见的喷流沉积岩。含矿地层受倾向北东的F_1区域断裂的影响,在断层沟一带表现为强烈片理化,大部分原始层理消失,原始地层倾向可能为南西,与锡铁山区相同。主要矿化为脉状铅锌矿,赋矿层位与锡铁山矿区相同,受片理及北西向断裂控制,是原始喷流沉积形成的矿体或初始富集层受F_1断裂作用改造形成的热液型矿体。成矿系统与矿床成因的研究表明,中间沟一断层沟一带,仍属喷流沉积成矿系统的中远端,具备形成大规模条纹条带状铅锌矿体的条件,但F_1断裂改造、成矿后的喷口活动均会对矿体起破坏作用。The Duancenggou target occurred at the southeastern part of Xitieshan lead - zinc deposit, the deposit has been recog- nized as a completely marine exhalative sedimentary system （SEDEX）. The host strata of the a- b member of Tianjianshan Group in which the Xitieshan lead - zinc orebody occurs, extends to Duancenggou area from the deposit area along NW - SE trending. In this target area, intensive exhalative sedimentary rocks including marble and quartz albite rocks of the Tianjianshan Group. ~he geological and geochemical characteristics of the marble indicates that the origin of the marble is the product of the interaction between the exhala- tive brines and the sea water, which is same as that in the Xitieshan deposit area. The layered quartz - albite sedimentary rocks also in- dicates that it is formed in the distal environment of the SEDEX system, which commonly occurred in many SEDEX deposits. The host rocks in the target area is strongly foliated by the NE - trending regional fault named as F~. The bedding in the host rock was strongly and rarely kept, and the original strata maybe dips SW, which is same as that in the Xitieshan deposit area. The main mineralization type is the vein type lead -zinc in the stratum same as in the deposit area, and controlled by the schistosity structure and F~ fault. The lead - zinc veins are formed by the reformed activity of the original exhalative sedimentary orebodies or initially lead - zinc enrichment layers. Based on the study on the mineralization system and the deposit genesis, it shows that the Zhongjiangou - Duancenggou area is still located at the central and distal parts of the SEDEX system, and has a great potential for forming the banded lead - zinc orebodies. However the lead - zinc orebodies could be destroyed by the later stage regional F~ and the volcanic vents events.

关 键 词：铅锌矿床 喷流沉积型 地层地球化学 成矿预测 青海 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]