Greenstone Belt Gold Deposits and Their Ore Source Beds in Western Shandong
详细信息
- 责任者：Wang Jiguang (Institute of Geological Survey ; Jinan 250013 ; China) ; Li Jing
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(7)
- 页码：p.994-1002
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
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.