鲁西地区绿岩带型金矿及其矿源层探讨  

Greenstone Belt Gold Deposits and Their Ore Source Beds in Western Shandong

作　　者：王继广[1] 李静 李庆平 王巧云[1] 董志成[1] 

机构地区：[1]山东省地质调查院,济南250013 [2]山东省第五地质矿产勘查院,山东泰安271021 [3]山东省第一地质矿产勘查院,济南250013

出　　处：《地质学报》2013年第7期994-1002,共9页Acta Geologica Sinica

基　　金：中国地调局项目(编号200113000026和200110200051)资助的成果

摘　　要：鲁西泰山岩群是我国典型的新太古代绿岩带,发育并保存了良好的科马提岩,对其地质认识已基本趋于一致,但对鲁西地区绿岩带型金矿的认识还不够深入和全面。以往仅对韧性剪切带型金矿有所了解,对绿岩带层控型金矿很少重视,对矿源层的理解也较为模糊,笼统地将泰山岩群作为后期各种金矿成矿的矿源层。本文对鲁西绿岩带韧性剪切带型和层控型金矿做了系统介绍,认为绿岩带层控型金矿具有原生层状特征和矿源层意义,受绿岩带某特定层位控制十分明显,是超基性岩—基性火山岩—碎屑沉积岩建造旋回过程中发展到一定阶段的产物。对鲁西地区金矿源层成生发育机制进行了探讨,认为绿岩带中金初始沉积矿化层位十分狭窄,厚度一般仅1至十几米,但横向分布较广泛,一般长达5～10km以上,初始沉积金品位一般在10×10-9～0.5×10-6,其金质来源于海底火山喷流(热液和喷气)作用。阐述了金矿源层与条带状硅铁建造(BIF)往往密切伴生的成因联系,并与硅铁矿层一样,也具有多旋回性沉积特点。韧性剪切带型金矿受矿源层内在控制,产于矿源层内或附近。Taishan Group in western Shandong is the typical Late Archean greenstone belt in China ,where the komatiite developed and arewell preserved.But there has been no a consensus among geologists on its geologic understanding.The interpretation of greenstone belt gold deposits inwestern Shandong is still superficial.Previous studies mainly focused on the ductile shear zone type gold deposits , and less concern has been paid on the greenstone belt strata-bound type gold deposits.And there is no much understanding for ore source beds , and Taishan Group is generally considered as the ore source beds for all the late gold deposits.Based on the systematic introduction of theductile shear zone type and strata-bound type gold deposits of greenstone belt in western Shandong , it is concluded that the greenstone belt gold deposits have primary layered characteristics.They are obviously controlled by some specific horizontal beds and the productdeveloping from the formation cycle of the ultra-mafic rock-mafic volcanic rock-clastic sedimentary rock.In addition , this studydiscussed the formation and development mechanism of gold ore source beds , inferring that the initial deposition and mineralization horizons of gold were very narrow ,with awidth of just 1to more than 10meters , butwith an extensive lateraldistribution from 5to 10km in length.The initialdeposition grade of goldwas generally 10×10 -9 ～0.5×10 -6 ,which originated from sub-seafloor volcanic exhalative process （ hydrothermal fluid anddegassing ） .Furthermore , this paper discussed the genetic relationship between the gold ore source bed and the banded iron ore formation （ Anshan type irondeposit ）, suggesting that the gold ore source beds are characterized with multi-cycledeposition , the same as the banded iron formation.Finally , the result shows that ductile shear zone type gold deposits are controlled by distribution of ore source beds , mainly occurring within or around ore source beds.

关 键 词：绿岩带 韧性剪切带型金矿 绿岩带层控型金矿 金矿源层 鲁西 新太古代 

分 类 号：P618.51[天文地球—矿床学]