华北克拉通北缘岩浆Ni-Cu-(PGE)硫化物矿床地质特征、形成时代及其地球动力学背景

Geological Characteristics,Geochronology and Tectonic Settings of Typical Magmatic Ni-Cu-(PGE)Sulfide Deposits in the Northern Margin of the North China Craton

基于以往研究成果,笔者比较详细而全面地总结了华北克拉通北缘Ni-Cu-(PGE)硫化物矿床的基本特点、时空分布规律,并将该成矿带划分为四个成矿亚带:①吉黑成矿亚带、②辽吉成矿亚带、③燕冀成矿亚带和④白云鄂博成矿亚带。文中重新厘定了各个成矿亚带的形成时代,得出华北克拉通北缘Ni-Cu-(PGE)矿有三个主要成矿期,即古元古代吕梁期(2242～1962Ma)、晚古生代海西晚期(289～265Ma)和早中生代印支期(225～216Ma)。这三大成矿期所对应的地球动力学背景分别为华北克拉通北缘边缘裂陷环境、华北克拉通北缘晚古生代造山期后环境和古亚洲造山带的后碰撞-伸展环境。

The northern margin of the North China craton （NCC） Ni-Cu-（PGE） metallogenic belt is one of the regions in China characterized by the distribution of some important large-size or medium-size Ni-Cu-（PGE） sulfide deposits. The metallogenic belt has the following characteristics： ① special geotectonic location caused a variety of metallogenic tectonic settings; ②long-term and multi-period tectonic-magmatic activities resulted in multi-period lithogenesis and metallogenesis; ③regional metallogeny had multi-periods, with Mesozoic metallogeny being dominant; ④ the distribution of deposits in this region occurred as belts in east and west and concentrated in subsection mostly in the eastern part of Jilin province. Based on these results, this paper summarized the basic characteristics of Ni-Cu-（PGE） sulfide deposits in NCC and its spatial distribution regularities, divided the metallogenic belt into four sub-belts, i.e. , ①Ji- Hei metallogenic sub-belt, ② Liao-Ji metallogenic sub-belt, ③Yan-Ji metallogenic sub-belt, and ④ Bayan Obo metal- logenic sub-belt, and redetermined the metallogenic epoch of each sub-belt. Three major ore-forming periods of Ni-Cu- （PGE） sulfide deposits in the NCC area are 2242-1962 Ma （Paleoproterozoic Lüliangcan）, 289-265 Ma （Irate Paleo- zoic Late-Hercynian）, 225-216 Ma （Early Mesozoic Indosinian）, with the corresponding geodynamic settings being the marginal rift environment in the north margin of NCC, the Late-Paleozoic post orogenic environment in the north margin of NCC and the post-collision and extensional environment of Paleo-Asian orogenic belt, respectively.