Geochemical Study of Cretaceous Magmatic Rocks and Related Ores of the Hucunnan Cu–Mo Deposit: Implications for Petrogenesis and Poly-Metal Mineralization in the Tongling Ore-Cluster Region

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.

Metallogenic Model and Prospecting Progress of the Qiandongshan–Dongtangzi Large Pb-Zn Deposit, Fengtai Orefield, West Qinling Orogeny

“…Combined with the analysis of isotopic ages and trace element data, it is suggested that the Qinling Orogenic Belt was in the post-collision extensional stage after collision during the Indosinian period. Intense magmatic activity and mineralization occurred in this tectonic setting [13,27,[56][57][58][59] , which formed the basis for the formation of the Qiandongshan-Dongtangzi lead-zinc deposit. It shows obvious difference from typical Sedex lead-zinc deposit in the geological characteristics, the macroscopic and microscopic structural of lead-zinc ores, H-O-S-Pb isotopes, trace and rare earth element characteristics, mineralization age, and the relationship between ore body and granite, but they are closely related to magmatic-hydrothermal processes.…”

Deep Mineralization Background and Metallogenic Regularity of the Tongling Ore District

“…The ore field in this area is basically distributed in series along the east-west basement fault zone of Tongling city-Daijiahui, which clearly corresponds to the distribution of the shallow rock masses and is controlled by the same structure. There are more than 70 small rock bodies exposed on the surface of the study area, most of which are small rock bodies, rock branches or rock walls of medium-to-shallow facies, distributed in the metallogenic belt controlled by the basement fault of Tongling-Nanling, arranged in a nearly east-west banded pattern (Li and Tan, 1989;Shi et al, 2019aShi et al, , 2020. The main rock combination includes pyroxene monzodiorite, granodiorite, quartz monzodiorite and monzoite, which are part of a high potassium calc alkaline rock series.…”

Geochemistry and Geochronology of Intermediate Rocks in the Jiangshan Au Deposit in the Bengbu Uplift, North Anhui Province: Clues to Regional Au Mineralization

“…As an empirical index, oxygen fugacity can be used to judge the relationship between rock mass and mineralization (Ballard et al, 2002;Gu et al, 2020;Shi et al, 2020). Generally, highly oxidized magmas can control the behavior and speciation of sulfide, the behavior of Cu, Au being controlled by sulfur (Sun et al, 2017).…”