Lithostratigraphic and structural reconstruction of the Zn-Pb-Cu-Ag-Au Lemarchant volcanogenic massive sulphide (VMS) deposit, Tally Pond group, central Newfoundland, Canada

Cloutier, Jonathan; Piercey, Stephen J.; Lode, Stefanie; Guchte, Michael Vande; Copeland, David A.

doi:10.1016/j.oregeorev.2017.01.010

Cited by 13 publications

(1 citation statement)

References 64 publications

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“…This could promote sulphide precipitation in the rock as a stockwork [81]. The shallow position of the deposit provide suitable condition for the promotion of boiling near or at the seafloor [82], ultimately resulting in precious metals enrichment of the Divar deposit.…”

Section: Alterationmentioning

confidence: 99%

Tectono-Magmatic Setting of the Divar Deposit, Eastern Iran: Evidences for VMS Mineralzation

Pourkaseb¹,

Zarasvandi²,

Adelpour³

et al. 2017

Preprint

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The Divar VMS deposit is located in the Nehbandan ophiolite complex (NOC). It is hosted in the Sistan suture zone (SSZ) marking the boundary between the Lut and Afghan continental blocks. This area is composed mainly of various ophiolitic rock units representing a tectono-sedimentary mélange, which are commonly interpreted as being the remnants of Sistan oceanic lithosphere. The major host rocks cropping out in the Divar deposit are mantle peridotites include clinopyroxene-(cpx-) rich harzburgites and depleted harzburgites with gabbronorite, cumulate gabbro, basalt and pelagic sediments. They are interpreted as being related to the rifting and subsequent Late Triassic continental break-up of the southern Neothethys. In this study petrographic observations mineral chemistry with whole rock chemistry, and rare earth element (REE) modeling were carried out on the different rocks associated with Divar deposit. The presented data led to the following conclusions: (1) The depleted harzburgites proved to be related to the residual mantle after 18-22% removal of melts. This is comparable with abyssal peridotites; (2) The cpx-rich harzburgites represent the residual mantle after the removal of 11-13% mid-ocean ridge basalt-type (MORB). Subsequently, the residual mantle was enriched in light REE (LREE) by subduction-derived fluids; (3) The gabbronorite and cumulate gabbro represents a portion of oceanic crust generated in a mid-ocean ridge setting; (4) The basalts belong to the N-MORB-type with no considerable crustal contamination. From the top to bottom, the Divar deposit is characterized a gossan zone, a thick massive ore zone, and a poorly developed stockwork zone. In Divar deposit, host rocks are indicated by serpentinized peridotites and severely altered mafic rocks that include disseminated and stockwork ore under massive lenses. These rocks showed a mineral assemblage of carbonate + quartz-jasper + chlorite + albite + epidote that demonstrate greenschist facies ocean floor metamorphism. Moreover, in the footwall rocks, sericitization and hematitization are also observed. Primary mineralization includes bedded ore, sulphide breccias, stockworks and chimney fragments. Ore mineral abundances decrease from pyrite, magnetite, to chalcopyrite, and sphalerite. Highlightly, there are two distinct mineralization phases' namely massive sulphide (stage-1) and massive magnetite (stage-2). The spatial relationships with the host rocks and textural evidence (e.g., magnetite replacing sulphides) indicate that sulphide minerals and magnetite were generated in different stages. The transition from sulphide to magnetite mineralization is interpreted as being related to the variation of H2S content in the ore fluids. The massive sulphide ore (stage 1) might have formed by primary hydrothermal fluids enriched in H2S and Fe. The second stage (massive magnetite) seem to be related to the later hydrothermal fluids enriched in Fe but poor in H2S, replacing the pre-existing sulphide minerals. The lithological features (stockwork/massive or...

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Section: Alterationmentioning

confidence: 99%

Tectono-Magmatic Setting of the Divar Deposit, Eastern Iran: Evidences for VMS Mineralzation

Pourkaseb¹,

Zarasvandi²,

Adelpour³

et al. 2017

Preprint

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Light Stable Isotopes in Volcanic-Hosted Massive Sulfide Ore Systems

Huston

LaFlamme

Beaudoin

et al. 2023

Mineral Resource Reviews

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Volcanic-hosted massive sulfide (VHMS) deposits, the ancient analogues of “black smoker” deposits that currently form on the seafloor, are the products of complex mineral systems involving the interaction of seawater with the underlying volcanic pile and associated magmatic intrusions. Light stable isotopes, particularly those of oxygen, hydrogen and sulfur, have had a strong influence in determining sources of ore fluids and sulfur as well as elucidating geological processes important in the VHMS mineral systems. Oxygen and hydrogen isotope data indicate that evolved seawater was the dominant ore-forming fluid in VHMS mineral systems through geological time, although a small proportion of deposits, including high sulfidation and tin-rich deposits, may have a significant, or dominant, magmatic-hydrothermal fluid component. Higher-temperature (> 200 °C) interaction of evolved seawater alters the rock pile below the seafloor, producing δ18O depletion anomalies at the deposit and district scales that can be used as a vector to ore. In contrast, lower-temperature hydrothermal alteration results in δ18O-enriched zones that commonly cap mineralized positions. An apparent decrease in the degree of high temperature 18O depletion with time may relate to the increasing importance of felsic-dominated host successions in younger deposits. δ18O anomalies have potential as an exploration tool, and have contributed directly to discovery. The other important contribution of stable isotopes to understanding the VHMS mineral system is quantification of the contribution of sulfur sources. Conventional δ34S data, when combined with Δ33S data acquired using recently developed technologies, indicate that the dominant sulfur source is igneous sulfur, either leached from the volcanic pile or introduced as a magmatic volatile (these sources are not distinguishable). The thermochemical reduction of seawater sulfate is also an important, but subordinate, sulfur source. Estimation of the proportion of seawater sulfate with geological age indicate that, on average, it has increased from 5–10% in the Archean to 20–25% in the Phanerozoic. This most likely reflects the increase in seawater sulfate contents through geological time. Although untested as an exploration tool, variations in sulfur isotope data may have utility is discriminating fertile from barren sulfide accumulations or providing vectors to ores at the deposits scale. As exploration tools, light stable isotopes suffer from a relatively high cost and slow turn-around time. If these limitations can be overcome, and new analytical methods can be developed, light stable isotopes may emerge as another tool for exploration, particularly as discoveries are made at greater depth and under cover.

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Geology and lithogeochemistry of hydrothermal mudstones from the upper block near the Duck Pond volcanogenic massive sulfide (VMS) deposit, Newfoundland, Canada: evidence for low-temperature venting into oxygenated mid-Cambrian seawater

Piercey

Squires²,

Brace³

2018

Miner Deposita

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Lithostratigraphic and structural reconstruction of the Zn-Pb-Cu-Ag-Au Lemarchant volcanogenic massive sulphide (VMS) deposit, Tally Pond group, central Newfoundland, Canada

Cited by 13 publications

References 64 publications

Tectono-Magmatic Setting of the Divar Deposit, Eastern Iran: Evidences for VMS Mineralzation

Tectono-Magmatic Setting of the Divar Deposit, Eastern Iran: Evidences for VMS Mineralzation

Light Stable Isotopes in Volcanic-Hosted Massive Sulfide Ore Systems

Geology and lithogeochemistry of hydrothermal mudstones from the upper block near the Duck Pond volcanogenic massive sulfide (VMS) deposit, Newfoundland, Canada: evidence for low-temperature venting into oxygenated mid-Cambrian seawater

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