U-Pb Detrital Zircon Geochronology of Late Triassic to Early Jurassic Sandstones in the Northwestern Junggar Basin and its Implications

Xinchuan Lu,Shuncun Zhang,Shengyin Zhang,Xiangyang Xie,Arthur B Busbey,Guoqiang Sun,Jian Shi,Shekuan Du

doi:10.4172/2381-8719.1000320

Xinchuan Lu, Shuncun Zhang + Show 6 more

Open Access

https://doi.org/10.4172/2381-8719.1000320

Copy DOI

Abstract

The Junggar Basin is a Late Carboniferous foreland basin in northwestern China surrounded by different mountain belts. The west Junggar Basin has a complicated tectonic history with multiple subduction and collision events that controlled sedimentation and basin development. In this study, absolute dating of igneous rocks, rock geochemistry, and U-Pb detrital zircon geochronology were used to document the provenance of the Triassic-Jurassic clastic rocks in the northwest margin of Junggar Basin and determine local sources and tectonic setting. Granitic zircons with the youngest concordia age reveal the north Karamay pluton was formed at 292.6 ± 0.7 Ma, suggesting that they are postcollision granites. Late Triassic-Lower Early Jurassic strata were derived from Zhayier Mountain south of the Darbute fault. Starting with the Upper Early Jurassic Sangonghe Formation-Lower Middle Jurassic Xishanyao Formation, the strata changed from a single source to mix multiple sources. Sediment sources are widespread, including the northern Karamay granitic plutons, the area north of the Darbute fault, with potentially minor contributions from the southern margin of the Junggar Basin.

Highlights

The Central Asian Orogenic Belt (CAOB) is a typical pacifictype orogenic belt located among the East European, Siberian, North China and Tarim cratons [1] (Figure 1A)
Most efforts have been focused on the tectonic activity of the Tianshan orogenic belt, sedimentary records along the southern margin of basin or strata older than the Carboniferous, while sediment sources in the northwestern margin of Junggar Basin and the potential impact of Tianshan tectonic activity remains less constrained
Eight samples were selected, which are TZ-1, TZ2, TZ-5, TZ-7, SP-1 and SP-2, TZ-4 from the north Karamay granitic pluton in the Tuziakeneigou section, SP-3 from the granitic pluton in Sanping section, and were crushed by mortar to less than 200 powder mesh to measure the concentration of trace and rare earth elements with an inductively coupled plasma mass spectrometer (ICP-MS)

Summary

Introduction

The Central Asian Orogenic Belt (CAOB) is a typical pacifictype orogenic belt located among the East European, Siberian, North China and Tarim cratons [1] (Figure 1A). Previous studies have mainly focused on the Tianshan orogenic belt [3,4], and the Altay orogenic belt and east Junggar tectonic activations [5,6]. The northwestern margin of the Junggar Basin is an important potential area for hydrocarbon exploration and production [14,15,16]. Most efforts have been focused on the tectonic activity of the Tianshan orogenic belt, sedimentary records along the southern margin of basin or strata older than the Carboniferous, while sediment sources in the northwestern margin of Junggar Basin and the potential impact of Tianshan tectonic activity remains less constrained

Methods

Results

Discussion

Conclusion