TY - JOUR
T1 - Prototethyan Accretionary Orogenesis Along the East Gondwana Periphery
T2 - New Insights From the Early Paleozoic Igneous and Sedimentary Rocks in the Sibumasu
AU - Wang, Yuejun
AU - Qian, Xin
AU - Cawood, Peter A.
AU - Zhang, Yuzhi
AU - Wang, Yang
AU - Xing, Xiaowan
AU - Senebouttalath, Vongpaseuth
AU - Gan, Chengshi
N1 - Funding Information:
The authors would like to thank Drs. Q‐Y Gou, X Yang, C Xu, Z Liu, X‐Q Yu, X Qiu, and X‐H Lu for their experimental help. The authors thank Prof. Vinod Singh for their thorough and constructive comments and Prof. Claudio Faccenna for their editorial advice. Financial supports from the National Natural Science Foundation of China and Guangdong Province (41830211 and U1701641 and 2018B030312007 and 2019B1515120019) are gratefully acknowledged. Peter A. Cawood acknowledges support from the Australian Research Council grant FL160100168.
Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - 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 εHf(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.
AB - 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 εHf(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.
KW - igneous and sedimentary rocks
KW - outwardly propagating accretionary orogenesis
KW - peripheral East Gondwana
KW - Prototethyan consumption
KW - Sibumasu
UR - http://www.scopus.com/inward/record.url?scp=85106697774&partnerID=8YFLogxK
U2 - 10.1029/2020GC009622
DO - 10.1029/2020GC009622
M3 - Article
AN - SCOPUS:85106697774
SN - 1525-2027
VL - 22
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
IS - 5
M1 - e2020GC009622
ER -