U–Pb Dating and Trace Element Composition of Zircons from the Gujiao Ore-Bearing Intrusion, Shanxi, China: Implications for Timing and Mineralization of the Guojialiang Iron Skarn Deposit

Ze-Guang Chang,Guo-Chen Dong,Alireza K Somarin

doi:10.3390/min10040316

Ze-Guang Chang, Guo-Chen Dong + Show 1 more

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https://doi.org/10.3390/min10040316

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Abstract

The Gujiao ore field, located in the middle segment of the Lüliang Mountain in central North China Craton (NCC), is one of iron skarn deposits of western iron belt in China. The U–Pb dating results of zircon by LA-ICP-MS suggest that the ore-related monzonite from the Guojialiang deposit was formed at 129.7 ± 1.7 Ma, early Cretaceous, which is consistent with the timing of iron skarn deposits in the Handan–Xingtai district of western iron belt. The zircons of monzonite present notable positive Ce anomalies (Ce/Ce* = 23.38–45.85), high Ce4+/Ce3+ values (154–385) and relatively high oxygen fugacity (fO2 = −13.09 to −15.36), and yield relatively low Ti-in-zircon temperatures. The physico-chemical conditions of the Guojialiang deposit were quite similar to these of ore-bearing plutons in the Handan-Xingtai district. The ore-bearing magmas are derived from the enriched lithospheric mantle with crustal material contribution, which played key role in oxidation state of the magma and the iron mineralization in the western iron belt.

Highlights

The North China Craton (NCC) has experienced reactivation or decratonization during theLate Mesozoic [1,2,3], accompanied by large-scale magmatism and endogenic mineralization [4,5,6,7,8,9].The skarn-type iron deposit is one such mineralization type that has provided a crucial source of high-grade iron ores, especially in China [10]
Despite a majority of skarn-type iron deposits being associated with arc setting [11], the Mesozoic skarn Fe deposits in the NCC were generated within an intraplate extensional setting [8]
The ore-bearing magma had lower temperature and higher oxidation state compared to ore-barren magma

Summary

Introduction

The North China Craton (NCC) has experienced reactivation or decratonization during theLate Mesozoic [1,2,3], accompanied by large-scale magmatism and endogenic mineralization [4,5,6,7,8,9].The skarn-type iron deposit is one such mineralization type that has provided a crucial source of high-grade iron ores, especially in China [10]. The western iron skarn deposit belt consists of the Southern Taihang district ore deposit cluster, Gujiao (or Taiyuan) ore field, and Linfen ore field (Figure 1a). All these iron deposits in the western belt have similar ore-related intrusive rocks, monzonites, and/or diorites, and similar country rocks: Middle Ordovician marine carbonate rocks. There are few researches about the iron skarn deposits in the Gujiao ore field. These studies reported zircon U–Pb age and geochemistry of the Huyanshan complex in the Gujiao ore field [14,15]. The ore-bearing monzonite implication to iron skarn mineralization is still not clear in the Gujiao ore field

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