From Middle Neoproterozoic Extension to Paleozoic Accretion and Collision of the Eastern Tiklik Belt (the Western Kunlun Orogen, NW China)

Miao Sang,Zhiyong Zhang,Dongfang Song,Zhixin Zhang,Brian F Windley,Liang Li,Songjian Ao,Hao Wang,Qigui Mao,He Yang,Wenjiao Xiao,Jingmin Gan

doi:10.3390/min12020166

Abstract

The eastern Tiklik belt is mainly composed of meta-sedimentary rocks of the Ailiankate and Sailajiazitage Groups that were previously interpreted as Palaeoproterozoic, Mesoproterozic and Neoproterozoic stratigraphic units, which are part of the Tarim Precambrian basement. Our new detrital (U-Pb) zircon ages yield a dominant single peak with a major range between ca. 700 Ma and 800 Ma for meta-sedimentary rocks from both the Ailiankate and Sailajiazitage Groups, which demonstrates that they were mainly derived from an independent Neoproterozoic terrane. There are several ages of 444–659 Ma, of which, the youngest has an age of 444 ± 6 Ma, indicating that the time of deposition of the meta-sedimentary rocks could have been in the Early Silurian. The porphyritic granite sample has a weighted mean crystallization age of 442 ± 2 Ma. The adakite-like geochemical characteristics of the porphytitic granite suggest derivation from the melting of the oceanic slab and formation in a subduction, arc-related tectonic setting. After integration with relevant published data, our work suggests that the Ailiankate and Sailajiazitage Groups belong to a tectonic mosaic that contains Middle Neoproterozoic extensional and Paleozoic accretionary and collisional complexes, rather than the Paleoproterozoic or Mesoproterozoic basement, as previously regarded. We propose a new tectonic model for the eastern Tiklik belt that started with a Middle Neoproterozoic extension and ended with Paleozoic continuous accretion and collision in a Paleo-Tethys archipelago, which contributed to the considerable continental growth of the southern Tarim Block.

Highlights

The current tectonic activity in Asia has often been cited as a consequence of convergence and continental collision between India and Eurasia [1,2,3,4,5]
The older orogenesis that led to the conduption and closure of the PaleoTethys Ocean is less well-known, and yet it played an important role in the construction and growth of the Tarim Block and the early evolution of the Tibetan Plateau
We present the results of new field mapping and structural analysis integrated with new geochronologic and geochemical data from the eastern Tiklik belt in order to re-evaluate the relationships between the Tarim craton and the western Kunlun orogen, as their relevant structural boundaries and history of subduction and collage amalgamation are poorly understood

Summary

Introduction

The current tectonic activity in Asia has often been cited as a consequence of convergence and continental collision between India and Eurasia [1,2,3,4,5]. The older orogenesis that led to the conduption and closure of the PaleoTethys Ocean is less well-known, and yet it played an important role in the construction and growth of the Tarim Block and the early evolution of the Tibetan Plateau. Contains prime evidence for the evolution and closure of the Paleo-Tethys Ocean [7,8]. The rapid uplift of the western Kunlun orogen [6,7,9,10] caused juxtaposition of the basement of the Tarim Block and metamorphic rocks associated with the subduction and closure of Paleo-Tethys, hampering our understanding of the tectonic boundary between the Tarim Block and the western Kunlun orogen. During the Cenozoic, the Tiklik tectonic belt was thrust northward onto the Tarim basin, forming the junction between the western Kunlun orogen and Tarim craton (Figure 1). The tectonic relations and isotopic age variations of the Tiklik belt need to be re-evaluated in order to gain a better understanding of the contrasting tectonic senarios

Methods

Results

Conclusion