Abstract

The Qibaoshan polymetallic ore field is located in the Wulian area, Shandong Province, China. Four ore deposits occur in this ore field: the Jinxiantou Au–Cu, Changgou Cu–Pb–Zn, Xingshanyu Pb–Zn, and Hongshigang Pb–Zn deposits. In the Jinxiantou deposit, three paragenetic stages were identified: quartz–pyrite–specularite–gold (Stage 1), quartz–pyrite–chalcopyrite (Stage 2), and quartz–calcite–pyrite (Stage 3). Liquid-rich aqueous (LV type), vapor-rich aqueous (V type), and halite-bearing (S type) fluid inclusions (FIs) are present in the quartz from stages 1–3. Microthermometry indicates that the initial ore-forming fluids had temperatures of 351–397 °C and salinities of 42.9–45.8 mas. % NaCl equivalent. The measured hydrogen and calculated oxygen isotopic data for fluid inclusion water (δ18OFI = 11.1 to 12.3‰; δDFI = −106.3 to −88.6‰) indicates that the ore-forming fluids were derived from magmatic water; then, they were mixed with meteoric water. In the Changgou deposit, three paragenetic stages were identified: quartz–pyrite–specularite (Stage 1), quartz–pyrite–chalcopyrite (Stage 2), and quartz–galena–sphalerite (Stage 3). LV, V, and S-type FIs are present in the quartz from stages 1–3. Microthermometry indicates that the initial ore-forming fluids had temperatures of 286–328 °C and salinities of 36.7–40.2 mas. % NaCl equivalent. The measured hydrogen and calculated oxygen isotopic data for fluid inclusion water (δDFI = −115.6 to −101.2‰; δ18OFI = 12.2 to 13.4‰) indicates that the ore-forming fluids were derived from magmatic water mixed with meteoric water. The characteristics of the Xingshanyu and Hongshigang deposits are similar. Two paragenetic stages were identified in these two deposits: quartz–galena–sphalerite (Stage 1) and quartz–calcite–poor sulfide (Stage 2). Only LV-type FIs are present in the quartz in stages 1–2. The ore-forming fluids had temperatures of 155–289 °C and salinities of 5.6–10.5 mas. % NaCl equivalent. The measured hydrogen and calculated oxygen isotopic data for fluid inclusion water (δDFI = −109.8 to −100.2‰; δ18OFI = 10.2 to 12.1‰) indicates that the ore-forming fluids were derived from circulating meteoric waters. The sulfur isotopes (δ34Ssulfide = 0.6 to 4.3‰) of the four deposits are similar, indicating a magmatic source for the sulfur with minor contributions from the wall rocks. The ore field underwent at least two phases of mineralization according to the chronology results of previous studies. Based on the mineral assemblage and fluid characteristics, we suggest that the late Pb–Zn mineralization was superimposed on the early Cu (–Au) mineralizaton in the Changgou deposit.

Highlights

  • The Qibaoshan area, located to the northwest of Wulian town in Shandong Province, is an important polymetallic ore field

  • The measured hydrogen and calculated oxygen isotopic data for fluid inclusion water indicates that the ore-forming fluids were derived from magmatic water mixed with meteoric water

  • Based on the mineral assemblage and fluid characteristics, we suggest that the late Pb–Zn mineralization was superimposed on the early Cu (–Au) mineralizaton in the Keywords: stable isotopes; fluid inclusions; Qibaoshan polymetallic ore field; Jiaodong Peninsula

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Summary

Introduction

The Qibaoshan area, located to the northwest of Wulian town in Shandong Province, is an important polymetallic ore field. Proposed that the Jinxiantou deposit is a intermediate–low temperature hydrothermal deposit and the temperature and salinity of the main mineralization stage are 120–290 ◦ C and 2.9–14.7% NaCl equivalent, respectively, based on a study of the FIs from the quartz cement of the breccia-hosted ores. More data is required to characterize the mineralizing fluids in order to understand the ore genesis and determine the relationship between the different deposits in the Qibaoshan ore field. The new H–O–S isotopic data that we collected enabled us to determine the origins and evolution of the ore-forming fluids and propose a genetic model for the Qibaoshan polymetallic ore field

Regional Geology
Deposit Geology
Geologic
Jinxiantou Deposit
Changgou
Hongshigang Deposit
Xingshanyu Deposit
Fluid Inclusions
H–O–S Isotopes
Fluid Inclusion Petrography
Histograms
Changgou Deposit
Oxygen and Hydrogen Isotopes
Sulfur Isotopes
Sources of Ore Constituents
34 Fluid and Pressure–Temperature of by Trapping the δ34 SVCDT values
Sources and Evolution of the Hydrothermal System
1: Minerals such the and biotite and
Two Phases of Mineralization in the Qibaoshan Polymetallic Ore Field
Two phases of mineralization occurred in the Qibaoshan area
Conclusions

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