摘要
本文论述了我国长江中下游地区的成矿条件和成矿规律。以长江深断裂为主干的带状网络构造系统是成矿带的主导控岩、控岩构造。中生代扬子式同熔型第一成岩序列高钾花岗闪长岩类和第二成岩序列富钠闪长岩类分别与铜矿系列和铁矿系列有成因联系,并分别产于块断褶皱隆起区和断陷火山岩盆地及两者之间的过渡区。容矿层有特定的岩层组合,常含同生沉积矿(胚)层,具一定层控作用。本成矿带的成矿条件和规律可概括为“一断裂,二序列,三环境,四层位”。
The middle and lower reaches of the Changjiang River is one of the important metallogenic provinces in China.The tectonic unit underwent three different development stages,the geosynclinal,paraplatformal and interplate stages.During the interplate deformation stage,a nearly E-W trending arcuate downwarped zone convex toward the south was formed under the N-S-trending and NW-SE-trending compression.On the basis of the prominent difference between the southern and the northern basements by the end of Proterozoic,there formed a system of belted network structure with the Yangtze deep fault Zone as its mainstay,whichis of prime importance for controlling the formation and location of igneous rocks and ores.The rocks and the mineral deposits are characterized by their zonal distribution,but aggregation intervals along the various belts into groups at certain.Mesozoic magmatic activity is intense and widespread in the region.The rocks belong to two main magmatic series:the syntectic type and the anatectic type.The former is the most important and subdivisible into the Yangtze style(crust-mantle type)and the Jiangnan style(mantle-crust type).The Yangtze style may be further divided into two evolutionary suites.The fist,which is rich in alkalis and especially potassium is related to the formation of copper ores and the second,which is rich in alkalis and particulary sodium,is related to the formation of iron ores.The geological environments are directly related to ore formation.Copper deposits generally occur in relatively uplifted fold zones and skarn iron deposits occur in uplift-depression transitional zones,whereas sub-volcanic pneumato-hydrothermal iron deposits occur in volcanic depressions.Many deposits are of stratabound nature and occur as"multi-storeyed deposits".The ore-hosted horizons may be divided into four groups.The formation of the Early Carboniferous"Palaeo Tongling-Island"is related closely to the ore formation.The Middle Triassic gypsum(salt)-bearing layers have important influence on the formation of iron and sulphur deposits.It may be concluded that there are three main metallogenic models,viz:"Tongling model","Daye model"and"Ningwu model",when we consider the respective combined influences of the following ore-controlling factors,i.e.fractures,sequences of magmatic rocks geological environments and specific ore-hosted horizons.
作者
刘湘培
常印佛
吴言昌
Liu Xiangpei;Chang Yinfo;Wu Yanchang(Anhui Bureau of Geology and Mineral Resources;Anhui Institute of Geological Sciences)
出处
《地质学报》
1988年第2期167-177,共11页
Acta Geologica Sinica
