Early Neoproterozoic (870–820 Ma) amalgamation of the Tarim craton (northwestern China) and the final assembly of Rodinia

Pan Zhao,Yan Chen,Jinyou He,Chenglong Deng,Ross N Mitchell

doi:10.1130/g48837.1

Abstract

Abstract In the paleogeographic configuration of the Neoproterozoic supercontinent of Rodinia, the Tarim craton (northwestern China), traditionally seen as a single block, is placed either on the periphery near northern Australia or India or in a central position between Australia and Laurentia. To distinguish between these possibilities, we present here new primary paleomagnetic results from ca. 900 Ma volcanics in the Aksu region of the northwestern Tarim craton. The data reveal a ~28° latitudinal difference between the North Tarim and South Tarim blocks at ca. 900 Ma and constrain the age of amalgamation of the Tarim craton to between 870 and 820 Ma. Combining paleomagnetic poles from Tarim and major cratons of Rodinia with geological evidence, a two-stage orogenic model is proposed for the assembly of Rodinia. Late Mesoproterozoic orogenesis (1.3–1.0 Ga) led to the assembly of Australia–East Antarctica, Baltica, Umkondia, South Tarim, and Cathaysia with Laurentia, forming the core of Rodinia. Thereafter, the Jiangnan–Central Tarim Ocean separating North Tarim and Yangtze from South Tarim and Cathaysia was closed before ca. 820 Ma. This second Jiangnan–Central Tarim orogeny caused nearly coeval amalgamation of the peripheral Tarim and South China cratons by the welding of North Tarim and Yangtze to South Tarim and Cathaysia, respectively. The supercontinent of Rodinia was thus assembled by two orogenic phases separated by ~200 m.y.

Highlights

Since Hoffman’s (1991) proposal of a paleogeographic configuration of the Rodinia supercontinent, there have been many investigations of continents, cratons, and blocks aimed at deducing their relative positions in different models of the Neoproterozoic supercontinent (Fig. 1; e.g., Dalziel, 1997; Pisarevsky et al, 2003; Li et al, 2008; Evans, 2013; Merdith et al, 2021)
Most Rodinia models place Laurentia in a central position due to the surrounding Neoproterozoic passive margins, where it is surrounded by Baltica, Africa, Amazonia, Antarctica, Australia, and Siberia, with Asian cratons (e.g., South China and Tarim) on the periphery near Antarctica-Australia (Hoffman, 1991; Pisarevsky et al, 2003; Evans, 2013)
In order to test the Neoproterozoic collision of North Tarim and South Tarim and further constrain its paleogeographic location during the final assembly of Rodinia, we conducted a paleomagnetic study on the newly identified ca. 900 Ma volcanics of the Aksu region of northwestern Tarim (He et al, 2019)

Summary

INTRODUCTION

Since Hoffman’s (1991) proposal of a paleogeographic configuration of the Rodinia supercontinent, there have been many investigations of continents, cratons, and blocks aimed at deducing their relative positions in different models of the Neoproterozoic supercontinent (Fig. 1; e.g., Dalziel, 1997; Pisarevsky et al, 2003; Li et al, 2008; Evans, 2013; Merdith et al, 2021). Most Rodinia models place Laurentia in a central position due to the surrounding Neoproterozoic passive margins, where it is surrounded by Baltica, Africa, Amazonia, Antarctica, Australia, and Siberia, with Asian cratons (e.g., South China and Tarim) on the periphery near Antarctica-Australia (Hoffman, 1991; Pisarevsky et al, 2003; Evans, 2013). In order to test the Neoproterozoic collision of North Tarim and South Tarim and further constrain its paleogeographic location during the final assembly of Rodinia, we conducted a paleomagnetic study on the newly identified ca. The new data enable us to constrain an amalgamation of the Tarim craton to between 870 and 820 Ma through parallel subduction belts on the periphery of Rodinia and establish the age of final assembly of the Neoproterozoic supercontinent

GEOLOGICAL SETTING OF THE QIGELEKEKUOTAN VOLCANICS

Amazonia Baltica

AMALGAMATION OF TARIM The Precambrian crustal evolution of the