Abstract The Upper Devonian-Upper Triassic low-grade metasedimentary rocks exposed along the South Patagonian Andes preserve the structural record of deformation associated with pre-Andean orogenic phases that predated the inception of the Jurassic rift during Gondwana fragmentation. Through the structural analysis at different scales, we identified deformation structures mainly with cratonward vergence, produced at two stages of structure development for the Bahia de la Lancha (early Carboniferous) and Rio Lacteo (Middle Devonian-early Carboniferous) formations, and in a single one, for the Nunatak Viedma Unit (Late Triassic). The structural features were integrated with available U–Pb detrital zircon ages and fission-track cooling ages from those units. It leads us to identify a westward younging of sedimentation (i.e. protolith deposition) and widening of the continental margin throughout Paleozoic-early Mesozoic times, tectonically stabilized during the late Carboniferous-middle Permian Gondwanide orogeny and the Late Triassic-Early Jurassic Chonide orogeny. The structural style holds features of fold-and-thrust belts, which is discussed in a context of accretionary tectonics inherent to the Terra Australis exterior orogen.

中文翻译：

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阿根廷巴塔哥尼亚南部西冈瓦纳增生边缘的古生代-早中生代构造演化

摘要 沿南巴塔哥尼亚安第斯山脉出露的上泥盆统-上三叠统低品位变沉积岩保留了与前安第斯造山期相关的变形结构记录，这些变形早于侏罗纪裂谷在冈瓦纳碎裂期间的开始。通过不同尺度的构造分析，我们确定了以克拉通辐合为主的变形构造，产生于Bahia de la Lancha（早石炭世）和Rio Lacteo（中泥盆世-早石炭世）两个构造发展阶段一，Nunatak Viedma Unit（晚三叠世）。结构特征与这些单元的可用 U-Pb 碎屑锆石年龄和裂变径迹冷却年龄相结合。它引导我们确定沉积的向西年轻化（即 原岩沉积）和整个古生代-早中生代时期大陆边缘的加宽，在晚石炭世-中二叠世冈瓦德造山运动和晚三叠世-早侏罗世造山运动期间构造稳定。构造样式具有褶皱冲断带的特征，这在 Terra Australis 外部造山带固有的增生构造背景下进行了讨论。