Re-Os systematics of early proterozoic ferropicrites, Pechenga Complex, northwestern Russia: Evidence for ancient 187Os-enriched plumes

Walker, Richard J.; Morgan, John; Hanski, Eero; Smolkin, V. F.

doi:10.1016/s0016-7037(97)00088-4

Cited by 101 publications

(20 citation statements)

References 48 publications

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“…However, the S-isotope composition of sulfides from the western deposits are close to mantle values, and have been interpreted to indicate that most of the S is of mantle origin (Hanski 1992, Abzalov & Both 1997. Rhenium-osmium isotopic data from Pilgujärvi and Kammikivi are interpreted to indicate that contamination by crust occurred (Walker et al 1997). Melezhik et al (1994Melezhik et al ( , 1998 noted the apparent contradictory evidence for the source of S, but showed that the ␦ 34 S of the sediments evolves from -1.2‰ (i.e., close to mantle values) in the synsedimentary stage of formation of the sulfides to +9‰ in the late stages of diagenesis (Fig.…”

Section: Synthesis Of Existing Ideas and Development Of An Overall Modelmentioning

confidence: 94%

“…There, sulfides closest to the country rock show the greatest degree of contamination. Moreover, Walker et al (1997) attributed a variation in the Re/Os isotopes at Pilgujärvi to an increase in the degree of contamination close to the margins of the flow. We also wished to compare the composition of sulfides from the presumed flows erupted onto unconsolidated sediments (western deposits) with those emplaced into consolidated sediments (eastern deposits).…”

Section: Compositional Variations Along Traverses and Between The Easmentioning

confidence: 99%

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The Composition and Mode of Formation of the Pechenga Nickel Deposits, Kola Peninsula, Northwestern Russia

Barnes

Melezhik

Sokolov³

2001

The Canadian Mineralogist

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The Pechenga Ni-sulfide deposits, in the Kola Peninsula of Russia, are associated with ferropicrite flows and intrusions. The sulfides are divided into five types: 1) disseminated sulfides within the olivine cumulate portions of the ferropicrites, 2) massive sulfides, which occur at the contact between the ferropicrites and the country-rock black schists, 3) breccia-matrix sulfides, which occur at the contact between the ferropicrites and the schists, and in some cases continue for hundreds of meters subparallel to the contact but within the footwall, 4) chalcopyrite vein or stringer sulfides, which occur in the footwall, and 5) pyrite-rich layers, concretions and lenses in the sedimentary rocks. The disseminated sulfides have similarly shaped mantle-normalized patterns of chalcophile metal abundances to those of the ferropicrites, and could have formed in equilibrium with the ferropicritic magma at moderate R factors (250). The rocks are depleted in platinum-group elements (PGE), suggesting that the magma reached sulfide saturation prior to the formation of the ores. Sulfur isotope data indicate that the S was derived from the sediments onto and into which the ferropicrites were emplaced. The high As and Sb concentrations in the sulfides may have been derived from the sediments. The massive sulfides show a wider variety of composition than the disseminated sulfides; some sulfides are enriched in Os, Ir, Ru, Rh and depleted Pt, Pd, Ag, Au, Cu, Sb, As, Se. This pattern is attributed to the accumulation of monosulfide solidsolution during crystallization of a sulfide liquid. The sedimentary sulfides are richer in As and Sb than the disseminated and massive sulfides, but poorer in all the other chalcophile elements. The breccia-matrix sulfides consist of sedimentary and ultramafic fragments in a sulfide matrix. Compared with vein sulfides from other deposits, those from Pechenga have a very unusual composition. They are not only rich in Cu and Ag, but also in Os, Ir, Ru and Rh, and they are depleted in Pt, Pd, Au, As, Sb and Se.Keywords: nickel sulfide deposits, platinum-group elements, arsenic, antimony, gold, selenium, silver, rare-earth elements, ferropicrites, sulfur isotopes, Pechenga, Russia. SOMMAIRELes gisements de nickel de Pechenga, dans la péninsule de Kola, en Russie, sont associés à des coulées et des massifs intrusifs de ferropicrite. Les sulfures de nickel se présentent en cinq associations: 1) sulfures disséminés dans les parties cumulatives des ferropicrites, 2) sulfures massifs au contact entre les ferropicrites et les schistes noirs encaissants, 3) sulfures formant la matrice de brèches de ferropicrite et de schiste, dans certains cas se prolongeant des centaines de mètres le long du contact mais invariablement situés au dessus de la paroi inférieure, 4) veines de chalcopyrite ou sulfures en veinules, dans la paroi inférieure, et 5) accumulations de pyrite formant concrétions et lentilles dans l'encaissant sédimentaire. Les sulfures disséminés possèdent des tracés de concentrations en mét...

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Section: Synthesis Of Existing Ideas and Development Of An Overall Modelmentioning

confidence: 94%

Section: Compositional Variations Along Traverses and Between The Easmentioning

confidence: 99%

The Composition and Mode of Formation of the Pechenga Nickel Deposits, Kola Peninsula, Northwestern Russia

Barnes

Melezhik

Sokolov³

2001

The Canadian Mineralogist

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“…This is evident from the presence of the core components in the prod ucts of melting of the head parts of Neogean mantle plumes observed in picrobasalts of the Pechenga and Onega structures on the Baltic Shield with an age of 2 Ga [11,15], as well as in modern Hawaiian basalt [4].…”

Section: Sharkov Bogatikovmentioning

confidence: 95%

“…As is evident from the isotope data, fluid compo nents of the core substantively participate in the pro cesses of adiabatic melting in the head of mantle plumes and may reach the Earth's surface together with lavas [4,11,15]. Accordingly, mantle plumes sys tematically "sampling" the material of deep geo spheres are the only carriers of the core material, and study of the evolution of tectonomagmatic processes during the whole history of the Earth provides a unique possibility for obtaining of objective informa tion on the core evolution inaccessible by other meth ods as well.…”

mentioning

confidence: 98%

The problem of evolution of the Earth’s core: Geological, petrological, and paleomagnetic evidence

Шарков

Богатиков

2015

Dokl. Earth Sc.

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“…for plume-derived magmas have used geochemistry as evidence for such an interaction (Walker et al, 1995(Walker et al, , 1997Brandon et al, 1999;Ely and Neal, 2003;Chazey and Neal, 2004). Geophysical evidence suggests the presence of partial melts, convection, and strong physical heterogeneity at the D" layer (e.g., Vidale et al, 1998;Vinnik et al, 1998).…”

Section: Modelmentioning

confidence: 99%

Platinum-group element constraints on source composition and magma evolution of the Kerguelen Plateau using basalts from ODP Leg 183

Chazey

Neal

2005

Geochimica et Cosmochimica Acta

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Re-Os systematics of early proterozoic ferropicrites, Pechenga Complex, northwestern Russia: Evidence for ancient 187Os-enriched plumes

Cited by 101 publications

References 48 publications

The Composition and Mode of Formation of the Pechenga Nickel Deposits, Kola Peninsula, Northwestern Russia

The Composition and Mode of Formation of the Pechenga Nickel Deposits, Kola Peninsula, Northwestern Russia

The problem of evolution of the Earth’s core: Geological, petrological, and paleomagnetic evidence

Platinum-group element constraints on source composition and magma evolution of the Kerguelen Plateau using basalts from ODP Leg 183

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