Spatial distribution of sulfur isotope ratios associated with the Eagle Ni-Cu sulfide deposit in Upper Peninsula, Michigan: Implications on country-rock contamination in a dynamic magma conduit

Thakurta, Joyashish; Hinks, Benjamin Davis; Rose, Katharine

doi:10.1016/j.oregeorev.2019.01.008

Cited by 4 publications

(1 citation statement)

References 59 publications

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“…The nature of the contaminant can be diverse, including evaporates at Noril'sk-Tanakh (Grinenko 1985), graphitic shales at Duluth (Thériault and , paragneiss at Voisey's Bay (Ripley et al 2002), orthogneiss at Nebo-Babel (Seat et al 2009), (v) dolomite at Uitkomst (Li et al 2002), (vi) granite and shales at Eagle (Thakurta et al 2019), and (vii) juvenile crust at Huangshannan (Mao et al 2016). In the Platreef of the Bushveld Complex, a range of contaminants has been proposed including carbonates, sulphidic shale, and granitic gneiss (Barton et al 1986;Harris and Chaumba 2001;Maier et al, 2008;Ihlenfeld and Keays 2011;McDonald and Holwell 2011;Yudovskaya et al 2017).…”

Section: Magmatic Ni-cu-(pge) Sulphidesmentioning

confidence: 99%

The geotectonic setting, age and mineral deposit inventory of global layered intrusions

Smith

Maier

2021

Earth-Science Reviews

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Section: Magmatic Ni-cu-(pge) Sulphidesmentioning

confidence: 99%

The geotectonic setting, age and mineral deposit inventory of global layered intrusions

Smith

Maier

2021

Earth-Science Reviews

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Sulfur and copper isotopic signatures of chalcopyrite at Kalatongke and Baishiquan: Insights into the origin of magmatic Ni-Cu sulfide deposits

Tang

Qin

et al. 2020

Geochimica et Cosmochimica Acta

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A Preliminary Model for the Migration of Sulfide Droplets in a Magmatic Conduit and the Significance of Volatiles

Yao

Mungall

Qin

2019

Journal of Petrology

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Abstract A close relationship between Ni–Cu–(PGE) sulfide deposits and magmatic conduit systems has been widely accepted, but our present understanding still rests on empirical inductions that sulfide liquids are entrained during magma ascent and aggregated at hydrodynamic traps such as the opening of a conduit into a larger magma body. In this contribution, a preliminary quantitative model for the dynamics of mm-scale sulfide droplets in a vertical magmatic conduit is developed, examining such limiting parameters as the size, transport velocity and the magmas’ maximum carrying capacity for sulfide droplets. Addition of numerous dense sulfide droplets significantly reduces magma buoyancy and rapidly increases the bulk viscosity, and the resulting pressure gradient in the propagating conduit dyke restricts the maximum volume fraction of droplets that can be carried by ascending magma. For sulfide droplets alone, the maximum carrying capacity is low, but it will be improved dramatically by the addition of volatiles which reduces the density and viscosity of silicate melt. Potential volatile degassing during decompression further facilitates sulfide entrainment by reducing bulk magma density, and the formation of buoyant compound vapour-sulfide liquid bubble drops also greatly enhances the carrying capacity. The breakdown of compound drops by detachment of parts of the vapour bubble or sulfide droplet may occur at low pressure, which liberates sulfide liquids from rising compound drops, potentially to collect in traps in the conduit system. When sulfide-laden magma flows through a widening conduit, many droplets can be captured by the re-circulation flow just downstream of the expanding section, followed by sulfide liquid accumulation and enhanced chemical interaction via diffusive exchange with the recirculating magma, potentially resulting in an economic, high-tonnage ore body. We apply our models to the emplacement of sulfide-rich magmatic suspensions at Noril’sk and show that the disseminated mineralization in intrusions could have formed when magmas carrying re-suspended sulfide liquid entrained from pre-existing sulfide accumulations in the conduit system reached their limiting sulfide carrying capacity as dictated by buoyancy and were deflected into blind sills flanking the principal conduit for flood basalt volcanism.

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Spatial distribution of sulfur isotope ratios associated with the Eagle Ni-Cu sulfide deposit in Upper Peninsula, Michigan: Implications on country-rock contamination in a dynamic magma conduit

Cited by 4 publications

References 59 publications

The geotectonic setting, age and mineral deposit inventory of global layered intrusions

The geotectonic setting, age and mineral deposit inventory of global layered intrusions

Sulfur and copper isotopic signatures of chalcopyrite at Kalatongke and Baishiquan: Insights into the origin of magmatic Ni-Cu sulfide deposits

A Preliminary Model for the Migration of Sulfide Droplets in a Magmatic Conduit and the Significance of Volatiles

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