大别-苏鲁造山带在朝鲜半岛的延伸方式——基于~(40)Ar/~(39)Ar构造年代学的约束

本文结合野外构造变形特征观测,在朝鲜半岛的不同构造单元采集14件糜棱岩和片麻岩样品进行~(40)Ar/~(39)Ar年代学分析,在此基础上通过对比朝鲜半岛与大别造山带不同构造单元的变形特征,探讨大别苏鲁构造带在朝鲜半岛的东延特征,取得如下认识:朝鲜半岛中部的主要构造带在中生代经历了碰撞阶段(~210Ma)、逆冲推覆(200~150Ma)、造山后伸展阶段(140~90Ma)三个主要的构造过程;从变形期次和变形特征看,临津江构造带与大别造山带的北淮阳构造带、苏鲁构造带北部威海地区具有可比性,沃川构造带与南大别构造带有相似之处;在朝鲜半岛,自临津江带至沃川带构成了较完整的中生代碰撞造山带,即大别-苏鲁造山带的东延部分,原认为的"京畿地块"应属造山带的一部分。

The extension of the Dabie-Sulu orogenic belt in Korean Peninsula:Based on 40Ar/39Ar Tectonic chronology.

In this study, ⁴⁰Ar/³⁹Ar dating was done on 14 biotites or hornblende mineral separated from mylonites and gneiss in shear belts from different tectonic position of Korean Peninsula. Depending on the deformation characteristics of geological sections and associative tectonic chronology data, comparison was made between Korean Peninsula (include Rimjingang Belt and Okchon Belt) and Dabie-Sulu orogenic belt, and the eastward extension of Dabie-Sulu orogenic belt was discussed. As a result, Rimjingang belt of Korean Peninsula is similar to Beihuaiyang tectonic belt of North Dabie orogenic belt and north of Sulu belt in deformation characteristics and era, and Okchon belt is similar to South Dabie belt in the same ways. Furthermore, three main Mesozoic tectonic event of Korean Peninsula could be recognized such as:Collide Stage (T₁,~210Ma), Orogenesis Stage (T₂-J₃, 200~150Ma), Extensional Stage (K_1-2, 140~90Ma). On these bases, the geologic body between Rimjingang belt and Okchon belt is a holonomic Mesozoic orogene, as the eastern extending part of Dabie-Sulu orogenic belt, and "Gyonggi Massif" should be redefined as a part of the orogenic belt.