摘要
本文以不整合面的发现及同位素年龄为依据,重新厘定了本区早前寒武纪的地层,从而搞清了本区的大地构造格架,认为它类似于加拿大地盾的“洋葱构造”。本文将山东半岛划分为4个地体:胶北地体、鲁西地体、胶南地体、胶东南-苏东北-黄海地体。认为胶北地体成矿的大地构造背景与南非克拉通成矿背景十分相似。胶南地体、黄海地体对胶北地体的俯冲作用为胶北地体提供了大量的成岩成矿物质。根据胶北群和齐山群的地质及地球化学特征,认为胶北地体是在大洋基础上发展起来的O-型绿岩地体,有利于金矿的形成。
Jiaodong is the greatest Au-producing area in China. Based on the work of predecessors as well as a lot of isotopic ages and unconformities, the 'Jiaodong Group' that was originally considered to be Archeozoic in age are disintegrated into three parts the Jiaobei Group (Ar) , Qishan-Linjiazai Group (Pt1-1)and Jingshan Group (Pt1-2 - Pt1-3). According to the similarity in isotopic ages and geological and geochemical characteristics between the Jingshan and Fenzishan Groups, they may be combined into the Jingshan-Fenzishan Group which is determined to be the typical khondalite se- ries. So the tectonic setting in the area may be clear, which is similar to the 'onion structure' of the Canadian shield. On the basis of the geological and geophysical differences between the Jiaodong uplift area and its surrounding areas, four terranes can be defined: the Jiaobei, Luxi, Jiaonan and Yellow Sea terranes. The boundary faults between the various terranes are all dynamic matemor-phic belts. It is considered that the tectonic setting of the Jiaobei terrane is very similar to the metal-logenic tectonic setting of the South Africa craton. Large quantity of rock-forming and ore-forming metarials were provided by means of subduction of the Jiaonan and Yellow sea terranes toward the Jiaobei terrane. It can be considered from the geological and geochemical characteristics of the Jiaobei and Qishan Groups that the Jiaobei terrane is a O-type greenstone terrane (oceanic-greenstone terrain) developing from the ocean floor and is favourable to the formation of the gold deposit.
出处
《地质论评》
CAS
CSCD
北大核心
1995年第1期7-14,共8页
Geological Review
基金
国家自然科学基金 (94880100)
