From Breakup of Nuna to Assembly of Rodinia: A Link Between the Chinese Central Tianshan Block and Fennoscandia

Abstract

The transition from breakup of Nuna (or Columbia, 2.0-1.6 Ga) to assembly of Rodinia (1.0-0.9 Ga) is investigated by means of U-Pb and Lu-Hf data of detrital zircons from three Neoproterozoic metasedimentary rocks in the Central Tianshan Block (CTB), NW China. These data yield six age peaks around 1.0, 1.13, 1.34, 1.4-1.6, 1.75, and 2.6 Ga. Few zircons are detected between 2.0 and 2.5 Ga. The Paleoproterozoic to Neoproterozoic detrital zircons have Hf isotopic compositions (−22.1 to +13.0) similar to those of coeval magmatic rocks in the CTB, indicating a proximal provenance. These results, together with the geological evidence and the presence of 1.4 Ga orogenic granitoids in the CTB, rule out most cratons as the CTB sources but support a Fennoscandia ancestry. Zircon U-Pb ages and Hf isotopic compositions from the CTB and Fennoscandia suggest that from 1.8 to 1.4 Ga, the ε Hf (t) values increased toward more positive values, consistent with an exterior orogen characteristic that the lower crust was replaced by a juvenile arc crust. In contrast, from 1.4 to 0.9 Ga, zircon ε Hf (t) values decreased to more negative values, reflecting an interior orogen, characterized by enhanced contribution of recycled crustal material from collided continental fragments. This marked shift most likely reflected a transition from breakup of Nuna to assembly of Rodinia, accomplished by a transformation from an exterior orogen to an interior one.

Late Paleozoic Tectonic Evolution of the Paleo‐Asian Ocean in the Northern Alxa Block (NW China)

“…Similar to microcontinents in the Central Tianshan and southern Beishan, which have a tectonic affinity with the Baltica Craton (He, Klemd, Yan, & Zhang, 2018; Huang et al, 2019), the ZSZ is also considered to be a microcontinent within the PAO and was accreted to the northern margin of the Alxa Block along Quagan Qulu suture zone. Consequently, late Carboniferous to early Permian arc‐related volcanic rocks and sedimentary rocks (i.e., the latest marine sediments, Amushan Formation) along both sides of the Qagan Qulu suture zone (W. Zhang, Wu, Feng, et al, 2013; Zheng et al, 2017), forming in an active continental margin (Yin et al, 2016), suffered nearly E‐ to W‐trending fold and thrust deformation (Shi, Song, et al, 2016).…”

The Tectonic Implications of the Hongliuhe‐Xichangjing Ophiolitic Mélanges Belt in the Central Region of the Beishan Orogen, NW China — Constrained by the U‐Pb Ages of Detrital Zircons of the Metasandstones

“…9a). In the supercontinent stage of Rodinia, the thermal events of c. 900-800 Ma for the Tarim Craton and the Chinese Central Tianshan Block are widely reported (Zhang et al, 2007;Shu et al, 2011;He et al, 2014a;Huang et al, 2019), indicating that the two blocks combined into a unified continental block in this period (Fig. 9b), but the Chinese Central Tianshan Block recorded earlier thermal events, the Tarim Craton recording recorded later thermal events (Fig.…”

“…2500 Ma orthogneisses were interpreted to represent basement rocks of the Chinese Central Tianshan Block (Wang et al, 2014(Wang et al, , 2017. The basement rocks are mainly composed of gneisses and migmatites, with Precambrian metasedimentary covers that are composed of clastic rocks, limestones and quartzites (2000-730 Ma) (Hu et al, 1998(Hu et al, , 2000(Hu et al, , 2006(Hu et al, , 2010Liu et al, 2004;Wang et al, 2014;He et al, 2014bHe et al, , 2015bHuang et al, 2019). These rocks of Precambrian cover were then overlaid by Cambrian to Permian limestone, sandstone, siliceous rocks, shale and marble (XBGMR, 1993;Xiao et al, 2004).…”

“…In the southern margin of the CAOB, a large number of detrital zircons have been extracted from the Chinese Central Tianshan Block and the Tarim Craton. We selected previous data with high quality and large quantity as references (He et al, 2014a;Huang et al, 2019). The main age populations from the Chinese Central Tianshan Block are at 2700-2500 Ma, 2000-700 Ma (Fig.…”

Late Paleozoic tectonic evolution of the North Tianshan Belt: New structural and geochronological constraints from meta-sedimentary rocks and migmatites in the Harlik Range (NW China)

“…The Central Tianshan Belt (CTB) is composed of a Precambrian basement (Hu et al, 2000(Hu et al, , 2010Liu et al, 2004;Ma et al, 2012b;He et al, 2014;Wang et al, 2017;Han and Zhao, 2018;Huang et al, 2019), Ordovician to early Devonian arc-related volcanic and sedimentary sequences, and Paleozoic intrusive rocks (Xiao et al, 2004(Xiao et al, , 2013Shi et al, 2007;Lei et al, 2011;Ma et al, 2013;Zhong et al, 2015;Han and Zhao, 2018;He et al, 2018b). Both the basement and arc-type rocks are unconformably overlain by unmetamorphosed Carboniferous to Permian sediments (XBGMR, 1993).…”