朝鲜半岛与华北地质之对比研究:进展与问题

华北与朝鲜半岛山水相连,传统上称为中朝克拉通或中朝地块。但是中朝的地质对比研究并不深入。作者所在的研究组有幸同时与南北朝鲜半岛双方展开了合作研究达十年以上,内容涉及到前寒武纪基底、古生代沉积盆地、造山带演化、以及中生代岩浆活动。本文是对我们最新研究成果的一个简要总结,并提出一些仍未解决的或具争议的相关地质问题,希望以此能推动中朝地质和东北亚地质的研究。研究结果总结如下:(1)朝鲜半岛可划分为三个陆块,从北到南分别为狼林、京畿和岭南陆块,分别被临津江和沃川构造带分割;(2)三个陆块的前寒武纪基底虽有差别,但本文认为它们是相似的,并可与华北克拉通基底对比;(3)狼林地块的平南古生代盆地以及位于京畿陆块和岭南陆块之间的太白山古生代盆地与华北古生代盆地可对比;(4)临津江和沃川构造带的演化还有待深入研究,它们并不具有陆陆碰撞造山带的特征;(5)在京畿陆块西南部发现了含榴辉岩的三叠纪变质杂岩(洪城杂岩),其变质时代和岩石组合都可以和苏鲁造山带对比,不含超高压变质矿物。这表明苏鲁造山带东延到朝鲜半岛,并在半岛的京畿陆块西南缘登陆。但是洪城杂岩出露有限,没有穿越切割半岛的证据,因此可能沿半岛西部断裂局部分布或在半岛西缘尖灭,其空间分布需进一步研究;(6)中生代岩浆岩在朝鲜半岛广泛存在,三叠纪岩浆作用可能与印支期造山作用有关;侏罗纪和白垩纪的岩浆岩分布与华北在时代和空间分布上有所差别,晚白垩世岩浆岩在朝鲜半岛集中出露于庆尚盆地。本文还在最后一部分,提出了朝鲜半岛以及中朝对比研究中有争议的和尚需进一步研究的关键问题。

Comparative study of geology in North China and Korean Peninsula:Research advances and key issues.

In terms of geological and tectonic evolution, the Korea Peninsula (KP) has long been thought to be strongly tied with the mainland of China, with the North China Craton (NCC) and KP collectively termed as the Sino-Korea Craton, although such correlation suffered from the absence of relevant geological information and data in North Korea. This paper introduces our study of comparative study of geology in North China and Korean Peninsula, including Precambrian basements, Paleozoic basins, orogenic belts and Mesozoic magmatism. Main summary and conclusions are as follows. (1) The KP comprises three major Precambrian massifs i.e., Rangrim, Gyeonggi, and Yongnam massifs. The Rangrim and Gyeonggi massifs are separated by the Imjingang Fold Belt, while the Gyeonggi and Yongnam massifs are separated by the Ogcheon Fold Belt; (2) The basements of the three massifs are correlated to the NCC; (3) Two main Paleozoic basins within the Rangnim massif and within the Gyeonggi and Yongnam massifs are the Phyongnam basin and Taebaeksan basin that have a similar Paleozoic tectono-stratigraphy to the NCC; (4) Although, at present, the nature and tectonic significance of the Imjingang and Ogcheon belts remain controversial, these two structural belts do not show characteristics and natures of collisional orogenic belt; (5) The eclogite-bearing Hongseong Complex (HSC) is located in the southwestern part of the Gyeonggi massif and has been separated from the Gyeonggi complex. The eclogitic rocks are commonly associated with serpentinites, and occur as lenses in granitic gneiss. An eclogite sample yielded a metamorphic age of~230Ma and another protolith age of~880Ma. Its hosting granitic gneiss yielded an age of ca. 820Ma. All these age records indicate that the Sulu Belt extends to the KP. However, no evidence supports the HSC as a tectonic zone cuts across the KP. A crustal detachment-thrust model envisages that the collisional suture between the North China Block (NCB) and South China Block (SCB) was along the Western Marginal Fault Zone of the KP; (6) Mesozoic igneous rocks are widespread throughout the northern and southern parts of the KP. Triassic magmatism is related to Indosinian orogeny. Jurassic and Cretaceous igneous rocks are different from those in the NCC on ages and spatial-temporal distribution. Late Cretaceous volcanic rocks are located only in the Gyeongsang basin in the southeastern corner of KP. This paper also suggests several key and controversial academic issues that are worth to study in the future.