黑龙江省塔河县宝兴沟金矿床中生代侵入岩及其对成矿作用的制约  

Mesozoic intrusive rocks and their constraints on mineralization in Baoxinggou gold deposit in Tahe County,Heilongjiang Province

作　　者：周传芳[1] 王献忠[1] 李向文[1] 杨华本 宋贵斌[1] 段明新[1] 郭宏宇[1] ZHOU ChuanFang;WANG XianZhong;LI XiangWen;YANG HuaBen;SONG GuiBin;DUAN MingXin;GUO HongYu(No. 3 Gold geological Party, CAPF, Harbin 150086, Heilongiiang, China)

机构地区：[1]中国人民武装警察部队黄金第三支队,黑龙江哈尔滨150086

出　　处：《矿床地质》2018年第1期137-150,共14页Mineral Deposits

基　　金：中国地质调查局重要矿产资源调查计划(编号:[2015]02-14-03-002)资助

摘　　要：宝兴沟金矿床为近年来在漠河前陆盆地南缘新发现的大型金矿床。区内发育石英闪长岩、闪长玢岩、花岗细晶岩等侵入岩,矿体主要产于石英闪长岩、闪长玢岩内部及其与二十二站组砂岩的内外接触带中。地球化学研究表明,石英闪长岩具高钾、低钛、富碱特征,花岗细晶岩具高硅、高钾、低钛、富碱特征,二者均为高钾钙碱性系列岩石,富集大离子亲石元素Rb、Ba、Sr等,亏损高场强元素Nb、Ta、Ti和重稀土元素Yb、Y,但二者稀土元素特征和配分曲线差异较大,不具成因联系。矿石与石英闪长岩、闪长玢岩具有相似的微量元素、稀土元素组成和稀土元素配分曲线,表明石英闪长岩、闪长玢岩为成矿提供了热液和成矿物质等,与成矿具有密切的成因联系。LA-ICP-MS锆石U-Pb同位素测年结果显示,石英闪长岩成岩时间为118.13~121.77 Ma,限定了宝兴沟金矿床的形成时间不早于118Ma,为早白垩世,形成于太平洋板块俯冲后的伸展环境。漠河前陆盆地除中-晚侏罗世侵入岩外,早白垩世中酸性侵入岩对区域成矿也具有重要的作用,是今后找矿的重要方向之一。The Baoxinggou gold deposit is a large-sized gold deposit discovered in south Mohe foreland basin in recent years. Gold mineralization has close relationship with quartz diorite and dioritic porphyrite in this area. Orebodies mainly occur within the intrusion and its contact zone with the sandstone. A study of the geochemistry of this deposit shows that major elements in quartz diorite are characterized by high potassium, low titanium, and high alkali. Major elements in aplite granite are characterized by high SiO2, high potassium, low titanium, and high alkali. They both belong to the high-K calc-alkaline series. They have such geochemical features as relatively enrichment of large ion lithophile elements like Rb, Ba and Sr, depletion of high field strength elements like Nb, Ta, Ti and HREE Yb and Y. However, the characteristics and distribution curve of REE of the quartz diorite and the aplite granite show obvious differences, suggesting that they have no genetic relationship. As for trace element ratio on the cobweb map and the REE map, the trace elements and the REE distribution curves are close to curves of quartz diorite and dioritic porphyrite. They provided hydrothermal solution, mineralization material for ore-forming process, suggesting intimate relationship with mineralization. Zircon LA ICP MS U-Pb isotope dating shows that the rock-forming time of the quartz diorite is 118.13-121.77 Ma, indicating Early Cretaceous. This deposit was formed in an extension environment resulting from subduction of the Pacific plate to the Eurasian plate. Therefore, the mineralization of the Baoxinggou gold deposit was not earlier than 118 Ma. Besides the intrusive rocks of the middle-Late Jurassic, the medium acidic intrusion in Early Cretaceous also played an important role in regional mineralization, and hence it is one of the important prospecting directions in the future.

关 键 词：地球化学 锆石U-PB测年 成矿作用 中生代侵入岩 宝兴沟金矿床 

分 类 号：P618.51[天文地球—矿床学]