Abstract
The Hucunnan porphyry- and skarn-type Cu–Mo deposit is located in the south of the central Shizishan ore field of the Tongling ore-cluster region. The intrusive Hucunnan granodiorite, outcropping in this deposit, has adakitic geochemical features, and its magma is proposed to have originated from partial melting of the oceanic crust mixed with mantle-derived materials. The porphyry-type orebody is hosted in the granodiorite, whereas the skarn-type orebody occurs in the contact zones of intrusions and country rocks. The δ34S values of pyrite from the skarn orebodies ranged from +3.9 to +4.7‰ (avg. +4.3‰, n = 6), while those of the porphyry orebodies ranged from +5.1 to +6.2‰ (avg. +5.6‰, n = 4). 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios of the pyrites from the skarn orebodies were 38.04–38.45 (avg. 38.26), 15.55–15.66 (avg. 15.59), and 18.16–18.54 (avg. 18.44), respectively (n = 6). The pyrites in the porphyry orebodies had 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios of 38.24–38.36, 15.51–15.662, and 18.10–18.41, respectively (avg. 38.32, 15.58, 18.22; n = 4), respectively. The metallogenic model ages from Re–Os isotopic dating were 138.7 ± 1.9 and 140.0 ± 2.8 Ma, respectively. Geochemical data indicate that the ore-forming fluids in the skarn stage are characterized by high temperature, low acidity, and high oxygen fugacity, and the ore-forming materials were mainly from magma and partly from stratum, proving that the skarn orebody has more stratum materials than the porphyry orebody.
Highlights
Porphyry and skarn deposits are widely distributed in the world and represent the most important source of Cu, W, Fe, Mo, Pb–Zn, etc
There are more than 200 ore deposits in the Tongling ore-cluster region, which are divided into five ore fields: Tongguanshan (Cu, Au, Fe), Shizishan (Cu, Au, S, Pb, Zn), Xinqiao–Shujiaidan (Cu, S, Au), Fenghuangshan (Cu, Au, Fe), and Shatanjiao (Pb, Zn, Au, Cu) (Figure 1b) [11]
The Hucunnan Cu–Mo deposit, a medium-sized porphyry- and skarn-type deposit, is located in the south of Shizishan orefield in the Tongling ore-cluster region (Figure 1b)
Summary
Porphyry and skarn deposits are widely distributed in the world and represent the most important source of Cu, W, Fe, Mo, Pb–Zn, etc. Porphyry-skarn metallogenesis is a dynamic process, and the development of deposits depends on parameters such as the host rock types, geochemistry of the causative intrusions, and local tectonic history. These deposits can form in either convergent arc systems (island arcs or continental arcs) or collisional settings and they are closely related to intermediate to acidic intrusions [8,9]. Tongling ore-cluster region, and the geochronological, geochemical, and fluid of reported in numerous studies [30,31,32].
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