Premium
R e– O s and U – P b Geochronology of the D awan M o– Z n– F e D eposit in N orthern T aihang M ountains, C hina
Author(s) -
Song Yang,
Ding HaiYang,
Qu XiaoMing,
Wang RuiJiang,
Zhou Wei,
Wang ShuZhi
Publication year - 2014
Publication title -
resource geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 43
eISSN - 1751-3928
pISSN - 1344-1698
DOI - 10.1111/rge.12032
Subject(s) - quartz monzonite , geology , zircon , rhyolite , geochemistry , silicic , molybdenite , geochronology , isochron , volcanic rock , mineralization (soil science) , quartz , pluton , fluid inclusions , basalt , volcano , paleontology , tectonics , soil water , soil science
Abstract The Dawan M o– Z n– F e deposit located in the N orthern T aihang M ountains in the middle of the N orth C hina C raton ( NCC ) contains large M o‐dominant deposits. The mineralization of the D awan M o– Z n– F e deposit is associated with the M esozoic W anganzhen granitoid complex and is mainly hosted within A rchean metamorphic rocks and P roterozoic– P aleozoic dolomites. Rhyolite porphyry and quartz monzonite both occur in the ore field and potassic alteration, strong silicic–phyllic alteration, and propylitic alteration occur from the center of the rhyolite porphyry outward. The M o mineralization is spacially related to silicic and potassic alteration. The F e orebody is mainly found in serpentinized skarn in the external contact zone between the quartz monzonite and dolomite. Six samples of molybdenite were collected for R e– O s dating. Results show that the R e– O s model ages range from 136.2 Ma to 138.1 Ma with an isochron age of 138 ± 2 Ma ( MSWD = 1.2). U– P b zircon ages determined by laser ablation inductively coupled plasma mass spectrometry yield crystallization ages of 141.2 ± 0.7 ( MSWD = 0.38) and 130.7 ± 0.6 Ma ( MSWD = 0.73) for the rhyolite porphyry and quartz monzonite, respectively. The ore‐bearing rhyolite porphyry shows higher K 2 O / Na 2 O ratios, ranging from 58.0 to 68.7 (wt%), than those of quartz monzonite. All of the rock samples are classified in the shoshonitic series and characterized by enrichment in large ion lithophile elements; depletion in M g, F e, T a, N i, P, and Y ; enrichment in light rare earth elements with high ( L a/ Y b) n ratios. Geochronology results indicate that skarn‐type F e mineralization associated with quartz monzonite (130.7 ± 0.6 Ma) formed eight million years later than M o and Z n mineralization (138 ± 2 Ma) in the D awan deposit. From R e concentrations in molybdenite and previously presented P b and S isotope data, we conclude that the ore‐forming material of the deposit was derived from a crust‐mantle mixed source. The porphyry‐skarn type C u– M o– Z n mineralization around the Wanganzhen complex is related to the primary magmatic activity, and the skarn‐type F e mineralization is formed at the late period magmatism. The Dawan M o– Z n– F e porphyry‐skarn ores are related to the magmatism that was associated with lithospheric thinning in the NCC .