Geochronology, Geochemistry, and Pb–Hf Isotopic Composition of Mineralization-Related Magmatic Rocks in the Erdaohezi Pb–Zn Polymetallic Deposit, Great Xing’an Range, Northeast China

Zhitao Xu,Xiaolong Liang,Xiaolei Chu,Zhikai Xu,Jinggui Sun

doi:10.3390/min10030274

Abstract

Late Mesozoic intermediate–felsic volcanics and hypabyssal intrusions are common across the western slope of the Great Xing’an Range (GXAR). Spatiotemporally, these hypabyssal intrusions are closely associated with epithermal Pb–Zn polymetallic deposits. However, few studies have investigated the petrogenesis, contributions and constraints of these Pb–Zn polymetallic mineralization-related intrusions. Therefore, we examine the representative Erdaohezi deposit and show that these mineralization-related hypabyssal intrusions are composed of quartz porphyry and andesite porphyry with concordant zircon U–Pb ages of 160.3 ± 1.4 Ma and 133.9 ± 0.9 Ma, respectively. These intrusions are peraluminous and high-K calc-alkaline or shoshonitic with high Na2O + K2O contents, enrichment in large ion lithophile elements (LILEs; e.g., Rb, Th, and U), and depletion in high field strength elements (HFSEs; e.g., Nb, Ta, Zr, and Hf), similar to continental arc intrusions. The zircon εHf(t) values range from 3.1 to 8.0, and the 176Hf/177Hf values range from 0.282780 to 0.282886, with Hf-based Mesoproterozoic TDM2 ages. No differences exist in the Pb isotope ratios among the quartz porphyry, andesite porphyry and ore body sulfide minerals. Detailed elemental and isotopic data imply that the quartz porphyry originated from a mixture of lower crust and newly underplated basaltic crust, while the andesite porphyry formed from the partial melting of Mesoproterozoic lower crust with the minor input of mantle materials. Furthermore, a magmatic–hydrothermal origin is favored for the Pb–Zn polymetallic mineralization in the Erdaohezi deposit. Integrating new and published tectonic evolution data, we suggest that the polymetallic mineralization-related magmatism in the Erdaohezi deposit occurred in a back-arc extensional environment at ~133 Ma in response to the rollback of the Paleo-Pacific Plate.

Highlights

The Great Xing’an Range (GXAR) in Northeast China is an important part of the Central AsianOrogenic Belt (CAOB) and is characterized by numerous late Mesozoic volcanics and intrusions [1,2,3,4,5,6].it is one of the major global producers of polymetallic Pb and Zn resources; the Erguna metallogenic belt in the (GXAR) is a world-famous Pb–Zn polymetallic metallogenic belt [7,8,9,10,11] that hosts various types of metalliferous deposits
The Erdaohezi deposit, which was discovered in 1980, is an epithermal Pb–Zn deposit in the the Erguna metallogenic belt (Figure 1A,B) [15], it is spatially associated with subvolcanic intrusions
This study presents new geochronological age constraints from zircon U–Pb dating, Pb–Hf isotopic compositions and petrogeochemical data from andesite porphyry and quartz porphyry in the Erdaohezi deposit

Summary

Introduction

Orogenic Belt (CAOB) and is characterized by numerous late Mesozoic volcanics and intrusions [1,2,3,4,5,6]. It is one of the major global producers of polymetallic Pb and Zn resources; the Erguna metallogenic belt in the (GXAR) is a world-famous Pb–Zn polymetallic metallogenic belt [7,8,9,10,11] that hosts various types of metalliferous deposits (such as porphyries, hydrothermal veins, and epithermal deposits). Few studies that have been performed on the petrogenesis, geochronology, major and trace element geochemistry, and Pb and Hf isotopic characteristics of the intermediate–felsic intrusions

Results

Discussion

Conclusion