Petrogenesis and Tectonic Setting of Ore-Associated Intrusive Rocks in the Baiyinnuoer Zn–Pb Deposit, Southern Great Xing’an Range (NE China): Constraints from Zircon U–Pb Dating, Geochemistry, and Sr–Nd–Pb Isotopes

Qing Zhao,Yanfei Zhang,Jianping Wang,Rongge Xiao,Dehui Zhang,Panpan Li

doi:10.3390/min10010019

Abstract

The Baiyinnuoer skarn Zn–Pb deposit, located in the Southern Great Xing’an Range, Northeast China, is the largest Zn–Pb deposit of the northern China, with a total reserve of 32.74 Mt at average grades of 5.44% Zn and 2.02% Pb. The Zn–Pb ore bodies are hosted in the Lower Permian Huanggangliang Formation. The results of zircon U–Pb geochronology show that the ore-associated granodiorite porphyry, granodiorite, and diorite were emplaced at 248 ± 1.3, 251 ± 1.8, and 249 ± 1.4 Ma, respectively. The granodiorites and granodiorite porphyry have low P2O5 (0.13–0.23 wt %) and A/CNK (0.79–1.05) values, and their SiO2 and P2O5 contents are negatively correlated, indicating I-type affinity. The positive εNd(t) values (+1.3 to +1.8) and young two-stage model ages (TDM2) (880–916 Ma) of the Baiyinnuoer intrusive rocks suggest that they might have formed by the mixing of both mantle and crustal materials. The variations in the major elements, Rb, Sr, and Ba, and the negative Nb–Ta–Ti anomalies indicate that fractional crystallization might have occurred during magma ascent. In combination with the regional geology, the new geochronological, geochemical, and isotopic data reveal that the ore-associated intrusive rocks at Baiyinnuoer were formed in a post-collision setting in the Late Permian.

Highlights

The Southern Great Xing’an Range (SGXR), Northeast (NE) China, located in the eastern part of the Central Asian Orogenic Belt (CAOB), is considered to be one of the most important metallogenic belts, hosting a number of skarn, porphyry, and magmatic–hydrothermal Pb–Zn–Ag–Cu–Mo polymetallic deposits [1,2,3,4] (Figure 1)
Detailed field observation around the south ore zone at Baiyinnuoer in this study revealed that the skarn-type Zn–Pb ore bodies occurred extensively, and these ore bodies developed along the contact zones between the Indosinian subvolcanic rocks and marbles
Indosinian subvolcanic rocks were emplaced in the Late Permian and we can constrain the age of magmatism at Baiyinnuoer to 251–248 Ma

Summary

Introduction

The Southern Great Xing’an Range (SGXR), Northeast (NE) China, located in the eastern part of the Central Asian Orogenic Belt (CAOB), is considered to be one of the most important metallogenic belts, hosting a number of skarn, porphyry, and magmatic–hydrothermal Pb–Zn–Ag–Cu–Mo polymetallic deposits [1,2,3,4] (Figure 1). The Baiyinnuoer skarn Zn–Pb deposit, located in the SGXR, is the largest Zn–Pb deposit in this region of northern China (Figure 1), with a total reserve of 32.74 Mt at average grades of 5.44% Zn, 2.02% Pb, and 31.4 g/t Ag [1,12,13]. The age of the ore-associated intrusions and the related skarn-type Zn–Pb mineralization in the Baiyinnuoer deposit is still controversial. Yi et al [16] estimated the age of the ore-related granodiorites as

Results

Discussion

Conclusion