投稿时间：2019-06-14
修订日期：2019-09-30
网络发布日期：2020-02-26
中文摘要:辽吉活动带是华北陆块最具代表性的古元古代造山/活动带，不仅发育巨量的古元古代陆壳沉积物质和岩浆活动，而且经历了十分复杂的构造演化过程，以及多期岩浆-变质事件的叠加改造。辽吉活动带的形成和构造演化时期，也是该区的一次重要成矿期，以矿种多、规模大、层状或层控为主而发育大型-超大型矿床为特点，其中菱镁矿、滑石、硼、铅锌、钴、金和铀等矿产具有重要的经济价值。辽吉活动带由出露厚度达万米的古元古代辽河群、集安群、老岭群和不同阶段、不同类型的岩浆岩所组成。其主体发育两套变质岩石：一套为变质碎屑岩-碳酸盐岩组合，以变质相相对较低为特征，出露地层为北辽河群和老岭群，形成于靠近龙岗陆块的被动大陆边缘浅海盆地环境；另一套是由变质火山-沉积岩系和辽吉花岗岩共同组成的地质构造单元，变质相相对较高，地层分布在南辽河群和集安群，形成于远离大陆边缘俯冲体系下的弧岩浆构造环境。此外，形成于与被动大陆边缘构造环境相关的成矿带内分布着菱镁矿床、滑石矿床、铜钴矿床和铀矿床等，形成于活动大陆边缘弧岩浆构造坏境内的成矿带主要分布硼、铅锌和金等矿床。研究表明，海城菱镁矿、后仙峪硼矿、翁泉沟硼矿、范家堡子滑石矿、大横路铜钴矿和猫岭金矿等矿床均具有大型-超大型规模，其中海城菱镁矿矿床储量达8.84亿吨，为世界之最的超大型矿床，翁泉沟硼矿床的B2O3储量高达2185万吨，为超大型矿床，占全国总储量的28.6%。辽吉古元古代活动带发育在太古宙克拉通基底之上，经历了有限的拉伸裂陷、岩浆侵位、（火山）沉积、碰撞拼贴、变质改造、隆升拆离和消亡等发展演化阶段，时限为2.2~1.8 Ga。辽吉活动带的成矿构造-岩浆演化可以划分为4个阶段：① 2.2~2.0 Ga岩浆作用和成矿阶段；② 2.0~1.9 Ga沉积作用和成矿阶段；③ 1.90 Ga大规模变质-变形和成矿阶段（碰撞造山期）；④ 1.89~1.82Ga碰撞后岩浆作用阶段。综上，辽吉活动带的形成与演化经历了从活动陆缘转变为被动陆缘最终碰撞造山的地壳演化和成矿作用过程，其中成矿作用是由两类不同成矿构造环境所控制。同时，本区又经历了中生代构造-岩浆成矿作用的叠加，使区内成矿作用更具复杂性、多样性和多期性。这种在同一个成矿区内，由双成矿带控制的成矿在国内外很少见。因此，该区是形成多种矿产大规模成矿十分有利的地区及找矿远景地区。
Abstract:The Liaoji belt is the most representative Paleoproterozoic orogenic/active belt in North China, which not only accepted a huge amount of Paleoproterozoic sedimentary material deposition and magmatic emplacement but also underwent a very complex tectonic evolution and multi-period magmatic-metamorphic events. The formation and tectonic evolution period of the Liaoji belt was also an important metallogenic period characterized by multiple minerals, large scale and layered or stratabound forms in this area, such as magnesite, talc, boron, leadzinc, cobalt, gold and uranium polymetallic deposits with significant economic value. The Liaoji belt is composed of Liaohe, Ji' an, Laoling groups and magmatic rock in different stages. The rock mass in this belt is compose of two sets of metamorphic rocks:one consists of metamorphic clastic-carbonate assemblages characterized by relatively low metamorphic facies, which exists in the North Liaohe and Laoling groups. The other is composed of metamorphic volcano-sedimentary rocks and Liaoji granite characterized by relatively high metamorphic facies, which exists in the South Liaohe and Ji' an groups, and it was formed under the arc magmatic tectonic environment in a subduction system far from the continental margin. In addition, magnesite, talc, copper-cobalt and uranium deposits are distributed in the metallogenic belt related to the passive continental margin; on the contrary, the boron, lead, zinc and gold deposits were formed in an arc environment of the active continental margin. These deposits are all of large to superlarge scale, such as Haicheng magnesite deposit, Houxianyu boron deposit, Wengquangou boron deposit, Fanjiapuzi talc deposit, Dahenglu copper-cobalt deposit and Maoling gold deposit. Among them, the Haicheng magnesite deposit is the largest deposit with the reserves of 884 million tons, and the Wengquangou boron deposit is a superlarge deposit with the reserves of B2O3 as high as 21.85 million tons, accounting for 28.60% of total reserves in China. The Liaoji active belt in Paleoproterozoic was developed on the cratonic basement in Archean, and experienced the evolutionary phases of limited extension-rift, magma emplacement, volcanic sediment, collision, metamorphism, uplift-detachment and extinction in 2.2~1.8 Ga. The evolution of mineralization, tectonism and magmatism of Liaoji active belt is composed of four stages:① 2.2~2.0 Ga magmatism and mineralization stage, ② 2.0~1.9 Ga sedimentation and mineralization stage, ③~1.9 Ga large-scale modification-deformation and mineralization stage (collisional orogeny stage), and ④ 1.89~1.82 Ga post-collision magmatism stage. In conclusion, the formation and evolution of the Liaoji active belt experienced the crustal evolution and mineralization processes from active continental margin to passive continental margin, in which the mineralizations were controlled by different tectonic environments. In addition, the mineralization was characteristics by complexity, diversity and multistage, due to the fact that this area experienced the superposition of Mesozoic tectonic magmatic mineralization. Double metallogenic belts controlling mineralization in the same area is rarely seen both in China and abroad. Therefore, this area is very favorable for the large-scale mineralization of many kinds of mineral resources and prospecting.
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基金项目:本文得到“中国地质调查局中国矿产地质与成矿规律综合集成和服务项目（矿产地质志）（编号：DD20160346）”资助
引用文本：
沈保丰,张阔,毕君辉.2020.辽吉古元古代活动带的双成矿带地质特征[J].矿床地质,39(1):1~18SHEN BaoFeng,ZHANG Kuo,BI JunHui.2020.Geological characteristics of double metallogenic belts in Paleoproterozoic Liaoji active belt[J].Mineral Deposits39(1):1~18
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