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长乐—南澳带位于华南大陆的东南缘,是揭示晚中生代古太平洋板块与欧亚大陆相互作用和华南陆缘地质演化的一条关键性构造带。该构造带的T3-J含煤地层不整合下伏于下白垩统南园组之下,或以角闪岩相包体形式赋存于晚侏罗—早白垩世片麻状花岗岩体内。这些具有透入性混合岩化特征的副变质岩包体(T3-J)与围岩(片麻状花岗岩)发生过同变形,并且被未变形的白垩纪岩体/脉侵入。这些晚三叠—早侏罗世地层的变质和变形具有朝陆内(NW)方向减弱的特征。下白垩统南园组普遍发生褶皱和绿片岩相变质,并且被未变质的上白垩统石帽山群不整合覆盖。长乐—南澳带的主要岩石单元与构造特征表明华南陆缘在晚中生代经历过两期挤压(造山)。在第一期挤压(造山)过程中,T3-J陆相地层发生褶皱和变质。随后,这些经历了变形和变质的T3-J沉积地层与中-上地壳的其他岩石在早白垩世早期发生构造折返,其间伴随着大规模同构造岩浆作用(147～135 Ma)和区域性混合岩化。在第二期挤压过程中,早白垩世南园组发生褶皱和变质。华南陆缘110～100 Ma的岩浆杂岩、100～90 Ma的A型花岗岩和90～80 Ma的双峰式火成岩可能分别与这次挤压事件及其后的地壳伸展、减薄过程有关。因此,华南晚中生代两大岩浆旋回(165～120 Ma和110～80 Ma)可能受控于同期的两大构造旋回(165～120 Ma和115～80 Ma)。每个构造旋回包括一个地壳受挤压增厚过程和一个随后发生的地壳伸展减薄过程。值得注意的是,华南沿海地区的晚中生代构造-岩浆作用与陆内同期构造-岩浆作用似乎具有可比性。
The Changle-Nan’ao zone is located on the southeastern margin of the South China continent and is a key tectonic zone for revealing the interaction between the Paleo-Mesozoic Paleo-Pacific plate and Eurasia and the geologic evolution of the southern China margin. The unconformity of the T3-J coal-bearing strata in this tectonic belt lies under the Lower Cretaceous Nanyuan Formation or in the form of amphibolite facies in Late Jurassic-Early Cretaceous gneiss. These peridotitic inclusions (T3-J) with intrusive mixed-rock features have been co-deformed with surrounding rocks (gneissic granite) and have been intruded by undeformed Cretaceous rocks / veins. These Late Triassic-Early Jurassic strata metamorphism and deformation have weaker features in the NW direction. The Cretaceous Nanyuan Formation generally occurs folds and greenschist facies metamorphism and is unconformable by the unconformated Upper Cretaceous Shiamishan Group. The main rock units and tectonic features of the Changle-Nanao zone indicate that the southern China margins experienced two stages of compression (orogeny) during the Late Mesozoic. During the first stage of extrusion (orogeny), the T3-J continental strata developed folds and metamorphism. Subsequently, these deformed and metamorphic T3-J sedimentary formations and other rocks in the mid-upper crust tectonicly reverberated during the early Early Cretaceous, accompanied by large-scale syn-structural magmatism (147-135 Ma) and regional mixing Petrified. In the second stage of extrusion, the Early Cretaceous Nanyuan Formation was folded and metamorphosed. The magmatic complex of 110-100 Ma in the southern margin of South China, the A-type granite of 100-90 Ma and the bimodal igneous rock of 90-80 Ma may be related to the crustal extension and thinning process after this crushing event respectively. Therefore, the two large magmatic cycles (165 ~ 120 Ma and 110 ~ 80 Ma) in late Mesozoic in southern China may be controlled by the two major tectonic cycles (165 ~ 120 Ma and 115 ~ 80 Ma) in the same period. Each tectonic cycle consists of a crustal crustal thickening process and a subsequent crustal extension thinning process. It is noteworthy that the Late Mesozoic tectono-magmatism in the coastal areas of South China seems to be comparable to the intracontinental tectono-magmatism.