Re–Os isotopic systematics of the Voisey's Bay Ni–Cu–Co magmatic ore system, Labrador, Canada

Lambert, David D; Foster, Jeffrey G; Frick, Louise R; Li, Chusi; Naldrett, A. J.

doi:10.1016/s0024-4937(99)00008-0

Cited by 95 publications

(32 citation statements)

References 49 publications

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“…7 intrusion have high and variable gOs(t) values ranging from 50 to 187 and rather restricted eNd(t) values (3−5; Fig. 14), which is inconsistent with Lambert et al (1999). bulk assimilation of the upper crust but can be well explained by selective assimilation of crustal sulfides.…”

Section: Crustal Contaminationmentioning

confidence: 88%

Origin of PGE-Depleted Ni-Cu Sulfide Mineralization in the Triassic Hongqiling No. 7 Orthopyroxenite Intrusion, Central Asian Orogenic Belt, Northeastern China

Wei¹,

Wang²,

Li³

et al. 2013

Economic Geology

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The ~216 Ma Hongqiling No. 7 intrusion is located in the southern margin of the Central Asian orogenic belt, northeastern China. It was the second largest Ni producer after Jinchuan in China. The intrusion crops out in an area of ~0.013 km 2 on the surface. It intruded gneisses and marbles of the Paleozoic Hulan Formation. The intrusion is mainly composed of orthopyroxenite (~95 vol %), with minor harzburgite and norite. Over 90 vol % of the intrusion contains disseminated, net-textured or massive sulfides. The bulk sulfide ores (recalculated to 100% sulfide) have low average PGE concentrations (5.6 ppb Os, 3.1 ppb Ir, 4.7 ppb Ru, 2.2 ppb Rh, 31 ppb Pt, and 11 ppb Pd) and high Cu/Pd ratios (3 × 10 5 −3 × 10 7 ), consistent with the compositions of sulfide liquids segregated from PGE-depleted magma. Olivine composition (Fo <86 mol %) indicates a fractionated parental magma. Back calculation shows that the parental magma was possibly derived by olivine fractionation from a primary magma containing ~16 wt % MgO. Numerical modeling indicates that PGE depletion in the parental magma of the Hongqiling No. 7 intrusion was due to previous sulfide segregation in the staging chamber. Whole-rock data show light rare earth element (REE) enrichments, negative Nb-Ta anomalies, and positive eNd (t = 216 Ma) values from 3 to 5, which can be explained by mixing of a mantle-derived magma with a granitic melt formed by magma underplating in the crust. The gOs (t = 216 Ma) values of sulfide ores vary from 50 to 187. The highly variable gOs(t) values coupled with similar eNd(t) values indicate preferential assimilation of crustal sulfides during magma rock interaction. Based on the observations, we propose that the parental magma of the Hongqiling No. 7 intrusion formed by contamination of mantle-derived, S-undersaturated magma by crustally derived granitic melt, together with olivine crystallization, in a staging chamber. The contaminated magma became PGE depleted due to sulfide segregation in response to crustal contamination. The PGE-depleted magma became S undersaturated again during ascent due to the negative effect of pressure on the maximum solubility of sulfur in magma. Upon arrival near the present level of the Hongqiling No. 7 intrusion a second event of sulfide segregation took place due to addition of crustal sulfides from immediate country rocks. The immiscible sulfide liquids and orthopyroxene crystallizing from the magma were retained in a dynamic conduit to form the ore-bearing intrusion while much of the magma left the conduit to form some of the nearby sulfidepoor intrusions. We suggest future exploration in the region to focus on olivine-bearing and orthopyroxenedominant intrusions with ages similar to that of the Hongqiling No. 7 intrusion.

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Section: Crustal Contaminationmentioning

confidence: 88%

Origin of PGE-Depleted Ni-Cu Sulfide Mineralization in the Triassic Hongqiling No. 7 Orthopyroxenite Intrusion, Central Asian Orogenic Belt, Northeastern China

Wei¹,

Wang²,

Li³

et al. 2013

Economic Geology

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“…The Re-Os isotopic system can determine the timing of mineralization, provides information on metal sourcing, and is a highly sensitive indicator of possible crustal involvement during ore formation (Foster et al, 1996;Lambert et al, 1999;Mao et al, 1999;Selby & Creaser, 2001;Stein et al, 2001). The Re-Os ages obtained during this study can be divided into two groups that identify two different periods of mineralization, consistent with the geology and mineral assemblages.…”

Section: Implications Of Molybdenite Re-os and Sulfur Isotopic Data Fmentioning

confidence: 51%

Two Periods of Skarn Mineralization in theBaizhangyanW–MoDeposit, SouthernAnhui Province, SoutheastChina: Evidence from ZirconU–Pband MolybdeniteRe–Osand Sulfur Isotope Data

Jiang

Xing

et al. 2015

Resource Geology

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The recently discovered Baizhangyan skarn-porphyry type W-Mo deposit in southern Anhui Province in SE China occurs near the Middle-Lower Yangtze Valley polymetallic metallogenic belt. The deposit is closely temporally-spatially associated with the Mesozoic Qingyang granitic complex composed of granodiorite, monzonitic granite, and alkaline granite. Orebodies of the deposit occur as horizons, veins, and lenses within the limestones of Sinian Lantian Formation contacting with buried fine-grained granite, and diorite dykes. There are two types of W mineralization: major skarn W-Mo mineralization and minor granite-hosted disseminated Mo mineralization. Among skarn mineralization, mineral assemblages and cross-cutting relationships within both skarn ores and intrusions reveal two distinct periods of mineralization, i.e. the first W-Au period related to the intrusion of diorite dykes, and the subsequent W-Mo period related to the intrusion of the fine-grained granite. In this paper, we report new zircon U-Pb and molybdenite Re-Os ages with the aim of constraining the relationships among the monzonitic granite, fine-grained granite, diorite dykes, and W mineralization. Zircons of the monzonitic granite, the fine-grained granite, and diorite dykes yield weighted mean U-Pb ages of 129.0 ± 1.2 Ma, 135.34 ± 0.92 Ma and 145.3 ± 1.7 Ma, respectively. Ten molybdenite Re-Os age determinations yield an isochron age of 136.9 ± 4.5 Ma and a weighted mean age of 135.0 ± 1.2 Ma. The molybdenites have δ 34 S values of 3.6‰-6.6‰ and their Re contents ranging from 7.23 ppm to 15.23 ppm. A second group of two molybdenite samples yield ages of 143.8 ± 2.1 and 146.3 ± 2.0 Ma, containing Re concentrations of 50.5-50.9 ppm, and with δ 34 S values of 1.6‰-4.8‰. The molybdenites from these two distinct groups of samples contain moderate concentrations of Re (7.23-50.48 ppm), suggesting that metals within the deposit have a mixed crust-mantle provenance. Field observation and new age and isotope data obtained in this study indicate that the first diorite dyke-related skarn W-Au mineralization took place in the Early Cretaceous peaking at 143.0-146.3 Ma, and was associated with a mixed crust-mantle system. The second fine-grained granite-related skarn W-Mo mineralization took place a little later at 135.0-136.9 Ma, and was crust-dominated. The fine-grained granite was not formed by fractionation of the Qingyang monzonitic Resource Geology Vol. 65,

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“…The numbers indicate the percentages of participation of the crustal materials. The calculated parameters of Nd (ppm), eNd(t), Sr (ppm) and ( 87 Sr/ 86 Sr) i are 4.4, ?7, 102 and 0.704 from picrites in Northern Vietnam as parental magmas; 20, -22, 220, 0.715 and 20, -10, 220, 0.715 as two components of the Yangtze middle/upper crust Os, a chalcophile element, is mainly hosted in sulfide (e.g., Ripley et al 1999Ripley et al , 2001 so that if crustal sulfide is selectively assimilated due to its low melting point (Ripley et al 1999;Lambert et al 2000;Lesher and Burnham 2001), the 187 Os/ 188 Os ratio of magmas would be substantially elevated. On the other hand, crustal sulfides have low Nd, Sr and REE and would not significantly affect Sr-Nd isotopic system and REE patterns.…”

Section: Differentiation Of Pge-depleted Evolved Magmasmentioning

confidence: 99%

“…Os, one of the PGE, is present at low concentrations in the crust (*0.05 ppb, Rudnick and Gao 2004) relative to the primitive mantle (3.4 ppb, Palme and O'Neill 2004). Re-Os isotope systematics thus provides a sensitive monitor of crustal contamination of mantlederived magmas and sulfide ore-forming processes (Walker et al 1994;Lesher and Stone 1996;Lambert et al 1999Lambert et al , 2000Sproule et al 1999Sproule et al , 2002. The combination of lithophile and chalcophile elements and Re-Os isotopes has proven to be a powerful tool for investigating the role of fractional crystallization and crustal contamination in sulfide saturation of magma.…”

Section: Introductionmentioning

confidence: 99%

Differentiation, crustal contamination and emplacement of magmas in the formation of the Nantianwan mafic intrusion of the ~260 Ma Emeishan large igneous province, SW China

Wang

Zhou

Sun

et al. 2012

Contrib Mineral Petrol

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The Nantianwan mafic intrusion in the Panxi region, SW China, part of the *260 Ma Emeishan large igneous province, consists of the olivine gabbro and gabbronorite units, separated by a transitional zone. Olivine gabbros contain olivine with Fo values ranging from 83 to 87, indicating crystallization from a moderately evolved magma. They have 0.2 to 0.9 wt % sulfide with highly variable PGE (17-151 ppb) and variable Cu/Pd ratios (1,500-32,500). Modeling results indicate that they were derived from picritic magmas with high initial PGE concentrations. Olivine gabbros have negative eNd(t) values (-1.3 to -0.1) and positive cOs(t) values (5-15), consistent with low degrees of crustal contamination. Gabbronorites include sulfide-bearing and sulfide-poor varieties, and both have olivine with Fo values ranging from 74 to 79, indicating crystallization from a more evolved magma than that for olivine gabbros. Sulfide-bearing gabbronorites contain 1.9-4.1 wt % sulfide and 37-160 ppb PGE and high Cu/Pd ratios (54,000-624,000). Sulfide-poor gabbronorites have 0.1-0.6 wt % sulfide and 0.2-15 ppb PGE and very high Cu/Pd ratios (16,900-2,370,000). Both sulfide-bearing and sulfide-poor gabbronorites have eNd(t) values (-0.9 to -2.1) similar to those for olivine gabbros, but their cOs(t) values (17-262) are much higher and more variable than those of the olivine gabbros. Selective assimilation of crustal sulfides from the country rocks is thus considered to have resulted in more radiogenic 187 Os of the gabbronorites. Processes such as magma differentiation, crustal contamination and sulfide saturation at different stages in magma chambers may have intervened during formation of the intrusion. Parental magmas were derived from picritic magmas that had fractionated olivine under S-undersaturated conditions before entering a deep-seated staging magma chamber, where the parental magmas crystallized olivine, assimilated minor crustal rocks and reached sulfide saturation, forming an olivine-and sulfide-laden crystal mush in the lower part and evolved magmas in the upper part of the chamber. The evolved magmas were forced out of the staging chamber and became S-undersaturated due to a pressure drop during ascent to a shallow magma chamber. The magmas re-attained sulfide saturation by assimilating external S from S-rich country rocks. They may have Communicated by T. L. Grove. Electronic supplementary materialThe online version of this article (

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Re–Os isotopic systematics of the Voisey's Bay Ni–Cu–Co magmatic ore system, Labrador, Canada

Cited by 95 publications

References 49 publications

Origin of PGE-Depleted Ni-Cu Sulfide Mineralization in the Triassic Hongqiling No. 7 Orthopyroxenite Intrusion, Central Asian Orogenic Belt, Northeastern China

Origin of PGE-Depleted Ni-Cu Sulfide Mineralization in the Triassic Hongqiling No. 7 Orthopyroxenite Intrusion, Central Asian Orogenic Belt, Northeastern China

Two Periods of Skarn Mineralization in theBaizhangyanW–MoDeposit, SouthernAnhui Province, SoutheastChina: Evidence from ZirconU–Pband MolybdeniteRe–Osand Sulfur Isotope Data

Differentiation, crustal contamination and emplacement of magmas in the formation of the Nantianwan mafic intrusion of the ~260 Ma Emeishan large igneous province, SW China

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