New geochronological and geochemical data document a new and widely distributed succession of igneous and sedimentary rocks within the Sibumasu that extend from SW Yunnan through SE Asia as far as Sumatra. Our data revealed the presence of an Ordovician‐Silurian (mainly ∼490–430 Ma) igneous zone. The early Paleozoic granites in the zone display similar elemental and Sr–Nd–Pb–Hf isotopic compositions. They were derived from a common mixed source of ancient crustal materials with a juvenile component and formed in a subduction‐related setting. Detrital‐zircon U‐Pb apparent ages from the previously defined Precambrian Lancang and Ximeng units in the SW Yunnan portion of the Sibumasu are in the range of 3,306–428 Ma and 3,316–512 Ma, with the youngest age‐peaks of 505 Ma and 447 Ma, respectively, indicating the lower Paleozoic (Cambrian‐Silurian) sedimentary sequences. The Tarutao Unit and its equivalents in the SE Asia portion of the Sibumasu yield the U‐Pb apparent ages of 3,177–510 Ma, suggesting the maximum deposited time being Cambrian‐Ordovician. All these detrital zircon U‐Pb ages define two main peaks of ∼554–528 Ma and 964–905 Ma with ε_Hf(t) values similar to those in the Qiangtang, Tethyan Himalaya, and eastern Indochina. The lower Paleozoic detritus in the Sibumasu were likely derived from the India‐Antarctica region of East Gondwana. We propose that the late Cambrian‐Silurian units formed in an outward‐propagating accretionary orogen in response to the consumption of the Prototethyan Ocean in SW Yunnan and SE Asia. Sibumasu might represent a part of the easterly migrating accretionary orogen along the northern margin of East Gondwana in the late Cambrian‐late Silurian.

中文翻译：

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东冈瓦纳外围的原生动物增生造山作用：西布马苏早期古生代火成岩和沉积岩的新见解

新的地质年代和地球化学数据记录了西布马苏地区内火成岩和沉积岩的新的，广泛分布的演替，其分布范围从云南西南部一直到东南亚直至苏门答腊。我们的数据显示存在奥陶纪-lur陵纪（主要为490-430 Ma）火成岩带。该地区早期的古生代花岗岩显示出相似的元素和Sr–Nd–Pb–Hf同位素组成。它们来自具有幼年成分的古地壳材料的常见混合来源，并在俯冲相关的环境中形成。锡伯马苏西南云南地区以前定义的前寒武纪澜沧和西盟单元的碎屑锆石U-Pb表观年龄在3306–428 Ma和3,316–512 Ma范围内，最小年龄峰值为505 Ma和分别为447 Ma 指示下古生界（寒武纪-lur陵纪）沉积层序。塔布陶单位及其在西布马苏东南亚地区的等价物产生的U-Pb表观年龄为3177-510 Ma，表明最大沉积时间为寒武纪-奥陶纪。所有这些碎屑锆石U-Pb年龄定义了两个主要峰，分别为554-528 Ma和964-905 Ma，其中ε_的Hf（t）值类似于在羌塘，特提斯喜马拉雅，和印度支那东部。西布马苏的下古生界碎屑可能来自东冈瓦纳的印度-南极洲地区。我们建议，响应于云南西南部和东南亚的原生原生海洋的消耗，寒武纪-泥浆纪晚期单元形成在向外传播的增生造山带中。Sibumasu可能代表了寒武纪晚期志留纪晚期东冈瓦纳北缘东移的增生造山带的一部分。