Neoproterozoic paleogeography of the Tarim Block: An extended or alternative “missing-link” model for Rodinia?

The Datong area is located in the western part of the Western Kunlun Orogen (WKO), occupying a key area of the Tethyan domain. Our new SHRIMP U–Pb zircon ages from the Datong area provide new information about the Palaeozoic evolution of the Western Kunlun Orogen. A 473.0 ± 2.8 Ma granite with 493.6 ± 4.8 Ma inherited zircons from the Kusilafu extrusive rocks is interpretation as an A‐type granite formed in a fore‐arc tectonic setting. The 485.5 ± 1.9 Ma granitoid of the Datongdong pluton combined with the 452.7 ± 7 Ma granitoid of the Datong pluton indicate that the Datong pluton is an intra‐oceanic arc complex formed by the southern subduction of the Proto‐Tethyan ocean crust. Zircons from gabbros of the Datong mafic–ultramafic complex have a 499.2 ± 2.1 Ma U–Pb crystallization age. Combined with its complicated whole‐rock geochemistry, we propose that there may have existed a Datong seamount in the early Palaeozoic. The detrital zircon results of Silurian–Devonian sandstones reveal that the Late Silurian sandstones have the characteristic zircons both from the Tarim Block and Datong Arc, suggesting that the Datong arc collided with the Tarim Block in the Late Silurian. The tectonic history of the WKO was characterized by a southern subduction of Proto‐Tethys terminated in the Late Silurian.

Section: Discussionmentioning

confidence: 99%

Early Palaeozoic accretionary tectonics of West Kunlun Orogen: Insights from Datong granitoids, mafic–ultramafic complexes, and Silurian–Devonian sandstones, Xinjiang, NW China

Xiao

Tian

2018

“…The Neoproterozoic tectonic evolution of the Tarim Craton and its location in the Rodinia supercontinent have been discussed in many studies (e.g., Evans, ; Ge et al, ; Ge, Zhu, Wu, Zheng, & He, ; He, Zhang, Zong, Wang, & Santosh, ; He et al, ; Hoffman, ; Li et al, , ; Wen, Evans, & Li, ; Wen, Li, & Zhu, ). Based on the fact that no typical Grenville‐age orogenic record was identified in the northern margin of the Tarim Craton but ca.…”

Section: Discussionmentioning

confidence: 99%

⁴⁰Ar/³⁹Ar ages and geological significance of Neoproterozoic–Cambrian mafic rocks in the Aksu–Wushi area, NW Tarim Craton

Zhu

Jourdan

et al. 2018

Self Cite

Mafic dyke swarms and continental flood basalts record crucial information on mantle dynamics, crustal palaeostress, and supercontinent cycle. However, these mafic rocks are relatively difficult to date using zircon U–Pb methods because autogenous magmatic zircons are rare or absent in the rapidly cooled mafic magmas and most zircons extracted from these rocks are likely captured from their wall rocks. One good example of this dilemma is the Precambrian mafic dykes and layered basites in the Aksu–Wushi area, NW Tarim Craton, from which abundant zircon U–Pb data have yielded age spectra similar to those of the detrital zircons from the associated (meta‐)sedimentary rocks. In this paper, we performed the first 40Ar/39Ar dating on separated mineral grains from the mafic dykes (plagioclase and amphibole) and layered basites (plagioclase and pyroxene) in this area. Amphiboles from a mafic dyke cross‐cutting the blueschist‐bearing Aksu Group yielded a 40Ar/39Ar plateau age of 744.5 ± 2.8 Ma, whereas pyroxenes from a layered basite within the Sugetbrak Formation yielded a 40Ar/39Ar plateau age of 521.0 ± 2.1 Ma. The 40Ar/39Ar plateau age of 744.5 ± 2.8 was interpreted as the crystallization age of the studied mafic dykes and provides a minimum constraint for the third phase of deformation of the blueschist terrane. The mini‐plateau age of 521.0 ± 2.1 Ma was interpreted as a minimum crystallization age for basite of the Sugetbrak Formation. We also conducted geochemical analyses on layered basites of the Sugetbrak Formation from the Xiaoenbrak Formation, and the results indicated that these layered basites shared a uniform geochemical characteristic. Combining geochronological and geochemical analyses, we propose that the basites of the Sugetbrak Formation probably recorded a rifting event on the north‐western margin of the Tarim Craton during Early Cambrian.

“…Paleogeographic reconstructions, paleomagnetic data, and correlation of the Middle to Late Neoproterozoic stratigraphy of the Tarim Basin have shown that the Tarim Block once formed part of East Gondwana and was connected to the Kimberley region of NW Australia (Chen, Xu, Zhan, & Li, ; Li & Powell, ; Li, Zhang, & Powell, ) and cannot appropriate as a “missing link” between Australia and Laurentia (Li et al, ; Lu, Li, Zhang, & Niu, ; Wen et al, ) because of the absence of a drifting sequence during supercontinent breakup after the amalgamation of the North and South Tarim terranes during 1,000–800 Ma (Turner, ; Xu et al, ).…”

Section: Main Sedimentary Sequences Of Major Cratonic Basins During Nmentioning

confidence: 99%

Main sedimentary sequences and stages of major cratonic basins during the breakup of Rodinia

et al. 2017

This paper summarizes the main sedimentary sequences of major cratonic basins during the breakup of Rodinia and the assembly of Gondwana and extracts evolutionary stages of the Neoproterozoic basins around the Paleo‐Pacific Ocean and Iapetus Ocean tracts. During the breakup of Rodinia, sedimentary sequences and evolutionary stages of the main basins in major cratonic blocks, such as Yangtze, Australia, Eastern American, Western American, and Western Africa cratons, mostly experienced intracratonic rifting, drifting or passive continental margin, carbonate platform construction, and foreland basin stages. The time of rifting to drifting transition in Congo‐São‐Francisco precisely marked the closure of the Adamastor Ocean between Congo‐São‐Francisco and Rio de la Plata and presaged the opening of the Iapetus Ocean. The time of rifting to drifting transition of Eastern American of Laurentia and West Africa initiated at ~580 Ma also signified the opening of the Iapetus Ocean. The time of drifting stage of the main basins around the Paleo‐Pacific Ocean tracts is not only earlier than those of the Iapetus Ocean tracts but also is characterized by diachronism. The time of drifting onset of basins in the Yangtze Block is ~720 Ma, the time of drifting initiation of the Adelaide Fold Belt in South Australia is 680 Ma, and the time of drifting stage of the south‐western margin of Laurentia occurred at 550 Ma. The different times of rifting to drifting transition of the Adelaide Fold Belt in South Australia, the Yangtze Craton, and Western American of Laurentia signified the nonisochronous opening of the Neoproterozoic Paleo‐Pacific Ocean.