Abstract The South China Block (SCB) is tectonically bounded by the Tethyan and Pacific subduction zones and the Qinling-Dabie HP-UHP metamorphic zone. Triassic tectonic activity was a key phase in the tectonic history of the SCB and in creating the fundamental framework of East Asia. The geometry and kinematics of the Triassic deformation sheds light on the mechanism driving intra-continental orogenesis in the SCB. Our new field- and mapped- based structural analysis, along with thermo-chronological dating results, reveal two distinct Triassic deformations in the southern SCB involving top-to-north dextral thrusting at ∼250-225 Ma and NE-trending sinistral transpression at ∼230-190 Ma. Early Triassic dextral transpression is marked by WNW-trending high-strain zones and thrust nappes/sheets, which might have been rooted beneath the Hainan-Yunkai basement along a low angle, mid-upper crustal basal detachment. It transformed from a thick-skinned fold-and-thrust belt to thin-skinned Jura-like patterns with northerly-propagating deformation. Late Triassic NE-trending sinistral transpression was accompanied by a series of the parallel folds and thrusts in the SCB interior, resulting in the development of the regional positive-flower geometry and reactivation of the pre-existing structures. Such signatures, in combination with the available geological, geochronological, and paleogeographic observations, suggest two-stage (early-middle and late Triassic) intra-continental orogenesis in the SCB, were controlled by the clockwise scissor-like closure of the Paleotethyan Ocean and its interactions with the adjoining blocks including deep-subduction beneath the North China Block and limited lateral extrusion due to the obstructing paleo-Pacific plate.

中文翻译：

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由古奥特提斯闭合和与相邻块体相互作用驱动的华南陆块三叠纪两期陆内造山作用

摘要 华南地块（SCB）在构造上以特提斯和太平洋俯冲带和秦岭-大别高压-超高压变质带为界。三叠纪构造活动是南海构造历史和建立东亚基本框架的关键阶段。三叠纪变形的几何和运动学揭示了驱动 SCB 大陆内造山作用的机制。我们新的基于现场和映射的结构分析，连同热年代学测年结果，揭示了南 SCB 的两个不同的三叠纪变形，涉及 ∼250-225 Ma 的从上到北的右旋逆冲和 ∼ ∼ NE 向的左旋挤压230-190 马。早三叠世右旋挤压以 WNW 趋势的高应变区和逆冲推覆/片为标志，它可能沿着一个低角度的中上地壳基底拆离扎根于海南-云开基底之下。它从厚皮的褶皱冲断带转变为薄皮的侏罗山状图案，并具有向北传播的变形。晚三叠世 NE 向左旋压压伴随着 SCB 内部的一系列平行褶皱和逆冲，导致区域正花几何形状的发展和先前存在的结构的重新激活。这些特征与现有的地质、地质年代学和古地理观测相结合，表明 SCB 存在两阶段（早-中-晚三叠世）陆内造山作用，