Publication Date:
2019
Description:
The sulfide‐telluride formation temperature is approximately 250 C, with logƒS2 from −14.3 to −7.3 and logƒTe2 from −17.4 to −9.4. Molybdenite has Re‐Os model ages of 162–164 Ma, which indicate that the main ore formation stage was in the Late Jurassic. The sulfur and Re isotope data suggest that the ore‐forming material is mainly derived from a crust‐dominated magma source, combined with a geodynamic setting, indicating that the Luanling deposit is possibly correlated with an unexposed and oxidized magmatic system.
Abstract
The Luanling gold telluride deposit in the Xiong'ershan region is located in the southern margin of the North China Craton. The deposit formed in four stages, that is, an early pyrite‐quartz stage (I), a pyrite‐molybdenite stage (II), a sulfide‐telluride‐gold stage (III), and a late carbonate stage (IV). Six species of telluride in stage (III) are recognized, including hessite, altaite, petzite, unidentified Au‐Ag‐Te mineral, empressite, and unidentified Ag‐Te‐S mineral. Gold occurs mostly as native gold and electrum along the microfractures of sulfides or the contact between sulfide and telluride. The mineralization temperature of stage I and stage III ranges from 296 to 377°C and 241 to 324°C, respectively. Tellurides in stage III precipitate at the logƒS2 from −14.3 to −7.3 and logƒTe2 from −17.4 to −9.4. The ores were formed in an oxidizing environment. The Re‐Os model ages of molybdenite are 162–164 Ma, which indicate that the main ore formation stage was in the Late Jurassic. The Re contents of five molybdenite samples from the Luanling deposit have a range of 36.32–81.95 ppm, except for one large value of 220 ppm, which indicates that the ore‐forming materials are mainly derived from a crustal‐dominated source. The δ34S values of sulfides range from −17.6 to −6.2‰, whereas those of sulfates are from 6.8 to 11.5‰. The δ34SΣS value of the ore‐forming system is 0.0–3.7‰, indicating that the sulfur of the Luanling deposit derived from a deep igneous source. Mineral association and isotope data of the Luanling deposit, together with its geodynamic setting, imply that this deposit belongs to a part of the metallogenic system of the Nannihu‐Sandaozhuang, Shangfangou porphyry molybdenum deposits, and the Late Jurassic granitic intrusions.
Print ISSN:
1344-1698
Electronic ISSN:
1751-3928
Topics:
Geosciences
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