Geodynamics of the Ogcheon Belt (South Korea)
Geodynamics of the Ogcheon Belt (South Korea)
复制标题
Ogcheon 带的地球动力学（韩国）
DOI：
10.1016/0040-1951(90)90187-d
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
H. Lapierre
中科院分区：
文献类型：
--
作者：
Dominique Cluzel;J. Cadet;H. Lapierre
奥川带是一组同变质的向东南方向的推覆体，它是受多期构造影响的早古生代裂谷中沉积的火山沉积序列变形的结果。它的前白垩纪构造是由三次主要造山事件造成的：晚志留世-泥盆纪（？）印支期（晚二叠世-三叠纪）和燕山期（中侏罗世-早白垩世）构造阶段，外部、原地或准原地单元代表具有浅水沉积的台地带，而内部则为裂谷相。永威层序形成于裂谷东南缘的外陆棚，与华南江南盆地有密切关系。在内部变质单元中，后寒武世-早奥陶世泥质、浊积岩裂谷变质沉积物覆盖在寒武系或寒武-早奥陶世台地层序之上。区分两个子域：上部单元（Chung Ju和Pibaryeong单元）代表盆地的深“轴向”部分，包含来自西北“狭窄”边缘的远飞石和大型石; 2下部单元（Turung San、Poeun和Iwharyeong）与位于深裂谷域和稳定的东南地台之间的“宽”边缘有关。后者以厚层海底碎屑流和碱性或过渡拉斑玄武岩类火山岩为特征，火山活动和块状重力流沉积与地壳减薄及随后的裂陷和掀斜作用密切相关。岩石地层学证据表明，不含碳酸盐的裂谷变质沉积物与寒武-奥陶纪台地序列在同一盆地内相互关联。中志留世后-中石炭世前的“Ogcheon”硅铝造山带导致裂谷闭合，但对台地区域的影响相对较小。形成了一条无蛇绿岩的陆内褶皱冲断带。这一构造事件可能与中国中部昆岭带和中国东南褶皱带的早古生代构造活动同时发生，中朝克拉通的最终形成发生在中石炭世之前，“磨拉石”沉积开始于日本西南部矢久野洋盆西缘的单一地台上。在晚二叠世和早三叠世时期，朝鲜的克拉通内“印支”构造作用标志着海洋区域的闭合和随后的本州地块向西碰撞。自晚三叠世以来，主要的平移运动发生在沿着NNE-SSW断裂，与同构造山间槽和重要的花岗岩化有关。
The Ogcheon Belt is a stack of synmetamorphic southeastward verging nappes resulting from the deformation of a volcanosedimentary sequence deposited in an early Palaeozoic rift which was affected by polyphase tectonics. Its pre-Cretaceous structure results from three main orogenic events: the “Ogcheon” (late Silurian-Devonian (?)), Indosinian (late Permian-Triassic) and Yenshanian (middle Jurassic-early Cretaceous) tectonic phases.The external, autochthonous or para-autochthonous units represent platform zones with shallow-water deposits whereas rift facies characterize the internal domain. The Yeongweol sequence, forming an outer shelf on the southeastern margin of the rift, displays affinities with the Jiangnan basin of South China. It is in wrench fault contact with the easternmost Duwibong sequence correlated with the North China-North Korea platform.In the internal metamorphic units, post-Cambrian-early Ordovician pelitic and turbiditic rift metasediments overlie a thin Cambrian or Cambrian-Ordovician early platform sequence. Two subdomains are distinguished: the upper units (Chung Ju and Pibaryeong units) representing the deep “axial” part of the basin contain distal flyshoids and large olistoliths derived from the northwestern “narrow” margin; the lower units (Turung San, Poeun and Iwharyeong) are related to the “wide” margin located between the deep rift domain and the stable southeastern platform. The latter transitional domain is characterized by thick submarine debris flows, and volcanics of alkali or transitional tholeiitic affinity.The volcanic activity and mass gravity flow sedimentation are closely related to the crustal thinning and subsequent rifting and tilting. Lithostratigraphic evidence allows the correlation of the unfossiliferous rift metasediments with the Cambrian-Ordovician platform sequence in one single basin.The post-middle Silurian-pre-mid-Carboniferous “Ogcheon” ensialic orogeny resulted in the closure of the rift with relatively minor effects in the platform area. It gave rise to an intracontinental fold-thrust belt without ophiolites. This tectonic event may have been contemporaneous with early Palaeozoic tectonism in the Quinling Belt in Central China and in the Southeast China fold belt.The definitive constitution of the Sino-Korean craton took place before the mid-Carboniferous and “molasse” sedimentation was initiated on a single platform located on the western edge of the Yakuno oceanic basin of Southwest Japan. In late Permian and early Triassic times, the closure of the oceanic area and the subsequent westward collision of the Honshu Block are marked in Korea by the intracratonic “Indosinian” tectonism. Since late Triassic times, predominantly transcurrent movements have occurred along NNE-SSW faults associated with syntectonic intermontane troughs and important granitization.