Early Permian Granitic Magmatism in Middle Part of the Northern Margin of the North China Craton: Petrogenesis, Source, and Tectonic Setting

Longxue Li,Dingling Huang,Xinyu Wang,Qingye Hou

doi:10.3390/min11020099

Abstract

The late Palaeozoic was an important period of tectonic evolution for the northern margin of the North China Craton (NCC). The source(s) and tectonic setting of early Permian granitoid rocks emplaced along the northern margin of the NCC are still unclear. These granitoids formed between ~295.4–276.1 Ma (uncertainties ranging from ±1.5 to ±7.8 Ma) according to zircon laser ablation inductively coupled mass spectrometry (LA-ICP-MS) and sensitive high-resolution ion microprobe (SHRIMP) U-Pb data. The Dadongou (DDG) pluton is an A1-type granite and the Dananfangzi (DNFZ) pluton is an A2-type granite. The Erdaowa (EDW), Lisicun (LSC), Wuhai (WH) and Gehuasitai (GHST) plutons are I-type granites. The Yuanbaoshan (YBS) dykes are diorite and syenodiorite. All the granitoids are enriched in large ion lithophile elements and light rare earth elements, depleted in high field strength elements and have negative εNd(t) and εHf(t) values. The A1-type granite was formed by the melting of the mafic crust. The A2-type granite was derived from partial melting of tonalite gneiss from the NCC crust and mantle materials. The EDW, LSC, WH and GHST granites mainly originated from partially melted granulite, with some mantle input. The YBS dykes are formed by the magma mixing of hot mantle melt and the relatively cold crustal magma. The northern margin of the NCC experienced anorogenic and collision tectonic stages, and the structural setting started to transform to post-collision at the later period of early Permian.

Highlights

The formation process and tectonic background of igneous rocks are important keys for understanding the geologic history of the continental margin
Large volumes of Palaeozoic and Mesozoic magmatic rocks are distributed along the northern margin of the North China Craton (NCC)
The evolution of the northern margin of the NCC was strongly influenced by the southward subduction and closure of the Paleo-Asian Ocean (PAO) from the early Palaeozoic to the Triassic [7,8]

Summary

Introduction

The formation process and tectonic background of igneous rocks are important keys for understanding the geologic history of the continental margin. The CAOB formed by subduction-accretion during the Palaeozoic as a result of the closure of the. The timing of subduction, accretion and the PAO closure are uncertain. The evolution of the northern margin of the NCC was strongly influenced by the southward subduction and closure of the PAO from the early Palaeozoic to the Triassic [7,8]. These magmatic rocks could provide insight into the timing of the PAO closure. Studies on early Permian magmatic rocks along the northern margin of the NCC have inferred that they were formed in different tectonic settings.

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