中国三叠纪大陆成矿体系

Preliminary study on the Triassic continental mineralization system in China

中国三叠纪大陆成矿体系是指在三叠纪(250~205Ma)时期发生于大陆环境(包括大陆边缘)的成矿作用及其成矿地质要素构成的整体。分布在阿尔泰、北山、华北地块北缘和南缘、辽吉、鄂尔多斯、西南三江、羌塘、上扬子、湘鄂赣、云开-雷琼等矿集区的10多个主要矿床成矿系列(亚系列)可大致构筑起中国三叠纪的大陆成矿体系。相对于燕山期而言,印支期的成矿作用较弱,即使是印支运动强烈的西南三江-松潘甘孜地区已知三叠纪矿产资源尚少,找矿潜力仍然很大,而以往被认为形成于海西期的一些矿床(如阿尔泰的大喀拉苏、小喀拉苏等伟晶岩型稀有金属矿床)或被认为形成于燕山期的一些矿床(如辽吉裂谷带的小佟家堡子金矿和高家堡子银矿),经近年来同位素年代学的研究证明实际上形成于印支期,或者经历了印支旋回的成矿过程。在三叠纪的整个演化历程中,华北与华南两大块体拼合在一起,华北陆块南缘和北缘的拼合带及各类古构造再度活化,成为内生矿产的主要成矿带;华北的鄂尔多斯等大陆盆地及华南的山间小盆地为煤炭、油气、膏盐等沉积矿产的形成创造了条件;西南特提斯构造域的演化经历了从海洋到陆地的构造大变局,尤其是印支运动为中国中生代以来大陆格局的形成起到了重要作用,也为四川盆地等盆山格局的形成及其矿产资源的富集奠定了基础。因此,三叠纪成矿系统不仅可以为构造改造提供综合依据,也可以为成矿预测提供理依据。

The Triassic mineralization system in China is composed of mineralization and all of the metallogenic series(sub-series) which formed in the continental environment(including the continental margin) during the Triassic(250-205 Ma) period.It is established that such metallogenic series such as those formed at Altai,Beishan,northern and southern margins of North China block,Liaoning-Jilin,Ordos,southwest Sanjiang area,Qiangtang,Upper Yangtze,Hunan-Hubei-Jiangxi border region,and Yunkai-Leiqiong,roughly constructed the Triassic mineralization system in China.Compare to Yanshanian,Indosinian mineralization is weaker.Sanjiang-Songpan Ganzi area in southwestern China has excellent protential of large-scale prospecting of deposits,even though the movement was strong in Indosinian.Recent isotope chronology studies have shown that,some deposits that were previously thought to have formed in the Hercynian(such as Dakalasu,Xiaokalasu pegmatitic rare metal deposits in Altai) or Yanshanian period(such as Xiaotongjiapuzi Au deposit and Gaojiapuzi Ag deposit in Liaoji rift zone)formed during the Indosinian period or experienced the mineralization process of the Indosinian cycle.During the whole evolution of Triassic,the two blocks of North China and South China were combined,and the combination zone and paleo-tectonics of the southern and northern edges of North China were re-activated and became the central metallogenic belt of the endogenous minerals.The continental basins such as the Ordos in North China and the small intermountain basins in South China have created conditions for the formation of coal,oil,gas,paste,and other sedimentary minerals.The evolution of the Tethys tectonic region in the southwest has undergone significant tectonic changes from the ocean to the land,especially the Indosinian movement,which has played an essential role in the formation of the continental pattern since the Mesozoic period of China.It has also laid a foundation for the formation of the basin-mountain pattern and the enrichment of its mineral resources in the Sichuan Basin.Therefore,the Triassic mineralization system can The Triassic mineralization system in China is composed of mineralization and all of the metallogenic series(sub-series)which formed in the continental environment(including the continental margin)during the Triassic(250-205 Ma)period.It is established that such metallogenic series such as those formed at Altai,Beishan,northern and southern margins of North China block,Liaoning Jilin,Ordos,southwest Sanjiang area,Qiangtang,Upper Yangtze,Hunan Hubei Jiangxi border region,and Yunkai-Leiqiong,roughly constructed the Triassic mineralization system in China.Compare to Yanshanian,Indosinian mineralization is weaker.Sanjiang Songpan Ganzi area in southwestern China has excellent protential of large-scale prospecting of deposits,even though the movement was strong in Indosinian.Recent isotope chronology studies have shown that,some deposits that were previously thought to have formed in the Hercynian(such as Dakalasu,Xiaokalasu pegmatitic rare metal deposits in Altai)or Yanshanian period(such as Xiaotongjiapuzi Au deposit and Gaojiapuzi Ag deposit in Liaoji rift zone)formed during the Indosinian period or experienced the mineralization process of the Indosinian cycle.During the whole evolution of Triassic,the two blocks of North China and South China were combined,and the combination zone and paleo-tectonics of the southern and northern edges of North China were re-activated and became the central metallogenic belt of the endogenous minerals.The continental basins such as the Ordos in North China and the small intermountain basins in South China have created conditions for the formation of coal,oil,gas,paste,and other sedimentary minerals.The evolution of the Tethys tectonic region in the southwest has undergone significant tectonic changes from the ocean to the land,especially the Indosinian movement,which has played an essential role in the formation of the continental pattern since the Mesozoic period of China.It has also laid a foundation for the formation of the basin mountain pattern and the enrichment of its mineral resources in the Sichuan Basin.Therefore,the Triassic mineralization system can provide not only comprehensive basis for tectonic rebuilding but also provides a theoretical basis for metallogenic prediction.