气候变化领域集成服务门户(CCPortal): New insights into the Precambrian tectonic evolution and continental affinity of the Qilian block: Evidence from geochronology and geochemistry of metasupracrustal rocks in the North Wulan terrane

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DOI	10.1130/B35059.1
	New insights into the Precambrian tectonic evolution and continental affinity of the Qilian block: Evidence from geochronology and geochemistry of metasupracrustal rocks in the North Wulan terrane
	Wang L.; Johnston S.T.; Chen N.
发表日期	2019
ISSN	167606
起始页码	1723
结束页码	1743
卷号	131 期号:2021-09-10
英文摘要	The Qilian block, one of the Precambrian terranes in the Qinling-Qilian-Kunlun orogenic system, is a critical region for reconstruction of the overall architecture and tectonic evolution of NW China. This investigation of zircon U-Pb and Lu-Hf isotopes and whole-rock geochemistry of a metasupracrustal sequence in the North Wulan terrane provides new insights into the Qilian block. A Statherian-Calymmian unit (ca. 1.67-1.5 Ga), dominated by Al- and Si-rich gneisses, arkosites, quartzites, and amphibolites with minor calc-silicate rocks and marbles, is interpreted to have been deposited during continental rifting. Detrital zircons show two main age populations of 2685-2276 and 2098-1761 Ma with mostly negative εHf(t) values (-14.0 to +3.6). The sources are characterized by mixed felsic to intermediate igneous rocks as well as recycled components and are interpreted as being derived from the Tarim craton because of the age distribution of their detrital zircons. A Stenian-Tonian unit (ca. 1.1-0.9 Ga) consists mainly of felsic gneisses, quartzites, calc-silicate rocks, marbles, metavolcanic rocks, and amphibolites. The metasedimentary rocks yielded detrital zircon ages clustering at ca. 1.64, 1.43, 1.3-1.2, 1.1, and 0.94 Ga with predominantly positive εHf(t) values (-7.1 to +9.7). One metavolcanic rock has an age of ca. 1110 Ma and εHf(t) values of +6.5 to +9.1. The provenance is dominated by local syndepositional arc-related igneous rocks with older detritus possibly from Laurentia, again based on the age distribution of the detrital zircons. The Central Qilian and Hualong terranes show strong affinities with the North Wulan terrane and together constituted a single coherent Qilian block prior to their involvement in the Qilian- North Qaidam orogen. The Qilian block was probably once part of the Tarim craton and had a strong linkage to South Tarim, which drifted from North Tarim during the breakup of Columbia in the early Mesoproterozoic. We suggest that, from the late Mesoproterozoic to early Neoproterozoic, the South Tarim-Qilian formed an active continental margin located close to Laurentia during the assembly of Rodinia. The final collision occurred in the early Neoproterozoic with the formation of a significant continent that included the reunified Tarim- Qilian as well as Qaidam-Kunlun and Qinling terranes, Alxa block, Kyrgyz-Chinese Tianshan, and Yili block. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184904
作者单位	School of Earth Sciences, China University of Geosciences, Lumo Road 388, Wuhan, 430074, China; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
推荐引用方式 GB/T 7714	Wang L.,Johnston S.T.,Chen N.. New insights into the Precambrian tectonic evolution and continental affinity of the Qilian block: Evidence from geochronology and geochemistry of metasupracrustal rocks in the North Wulan terrane[J],2019,131(2021-09-10).
APA	Wang L.,Johnston S.T.,&Chen N..(2019).New insights into the Precambrian tectonic evolution and continental affinity of the Qilian block: Evidence from geochronology and geochemistry of metasupracrustal rocks in the North Wulan terrane.Bulletin of the Geological Society of America,131(2021-09-10).
MLA	Wang L.,et al."New insights into the Precambrian tectonic evolution and continental affinity of the Qilian block: Evidence from geochronology and geochemistry of metasupracrustal rocks in the North Wulan terrane".Bulletin of the Geological Society of America 131.2021-09-10(2019).