Subduction, mantle metasomatism, and gold: A dynamic and genetic conjunction

2019 ◽  
Vol 132 (7-8) ◽  
pp. 1419-1426 ◽  
Author(s):  
David I. Groves ◽  
Liang Zhang ◽  
M. Santosh
Keyword(s):  
Subduction Zones ◽  
Massive Sulfide ◽  
Mantle Metasomatism ◽  
Gold Deposits ◽  
Genetic Models ◽  
Dynamic Factor ◽  
Convergent Margins ◽  
Copper Gold ◽  
Orogenic Cycle ◽  
Fluid Release

Abstract Global gold deposit classes are enigmatic in relation to first-order tectonic scale, leading to controversial genetic models and exploration strategies. Traditionally, hydrothermal gold deposits that formed through transport and deposition from auriferous ore fluids are grouped into specific deposit types such as porphyry, skarn, high- and low-sulfidation–type epithermal, gold-rich volcanogenic massive sulfide (VMS), Carlin-type, orogenic, and iron-oxide copper-gold (IOCG), and intrusion-related gold deposits (IRGDs). District-scale mineral system approaches propose interrelated groups such as porphyry Cu-Au, skarn Cu-Au-Ag, and high-sulfidation Au-Ag. In this study, the temporal evolution of subduction-related processes in convergent margins was evaluated to propose a continuum of genetic models that unify the various types of gold deposits. At the tectonic scale of mineral systems, all hydrothermal gold deposits are interrelated in that they formed progressively during the evolution of direct or indirect subduction-related processes along convergent margins. Porphyry-related systems formed initially from magmatic-hydrothermal fluids related to melting of fertile mantle to initiate calc-alkaline to high-K felsic magmatism in volcanic arcs directly related to subduction. Formation of gold-rich VMS systems was related to hydrothermal circulation driven by magmatic activity during rifting of oceanic arcs. Orogenic gold deposits formed largely through fluids derived from devolatilization of the downgoing slab and overlying sediment wedge during late transpression in the orogenic cycle. Carlin-type deposits, IRGDs, and some continental-arc porphyry systems formed during the early stages of orogenic collapse via fluids directly or indirectly related to hybrid magmatism from melting of lithosphere that was metasomatized and gold-fertilized by earlier fluid release from subduction zones near margins of continental blocks. The IOCGs were formed during postorogenic asthenosphere upwelling beneath such subduction-related metasomatized and fertilized lithospheric blocks via fluid release and explosive emplacement of volatile-rich melts. Thus, importantly, subduction is clearly recognized as the key unifying dynamic factor in gold metallogenesis, with subduction-related fluids or melts providing the critical ore components for a wide variety of gold-rich deposit types.

Evidence from lead isotopes regarding the genesis of ore deposits in the Chibougamau region, Quebec

1981 ◽  
Vol 18 (4) ◽  
pp. 708-723 ◽  
Author(s):  
R. I. Thorpe ◽  
Jayanta Guha ◽  
Jules Cimon
Keyword(s):  
Lead Isotopes ◽  
Spatial Association ◽  
Massive Sulfide ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Carbonate Sediments ◽  
Sulfide Deposits ◽  
Copper Gold ◽  
Genesis Of Ore Deposits ◽  
Isotope Analyses

Twenty-three lead isotope analyses are reported for massive sulfide deposits, the main copper–gold shear zone deposits in anorthosite of the Doré Lake complex, and two gold deposits, all in Archean terrane, in the Chibougamau district. Five analyses were also obtained for lead occurrences in Proterozoic carbonate sediments in the Mistassini Basin.Galenas from the Coniagas and Lemoine deposits of volcanogenic massive sulfide type, from the Taché Lake deposit of possibly the same type, from the Norbeau and Ayrhart gold properties, and one from within the Opemiska mine, have Archean compositions. Of these, the Lemoine, Norbeau, and Opemiska mine galenas are slightly younger than the others or were contaminated during later deformation and (or) metamorphism.Analyses for the main Cu–Au deposits generally form a cluster, although the spread in 206Pb/204Pb ratios is significant and three analyses for the Copper Rand deposit, in particular, are distinct from data for the other deposits. One interpretation is that the data, in combination with the Archean analyses, define a secondary isochron reflecting a primary age of Archean deposits and rocks at 2735–2800 Ma and a secondary event, including genesis of the Cu–Au ores, at 2240–2160 Ma. Additional evidence for a metamorphic–plutonic(?) event at about 2200 Ma has been provided by previous paleomagnetic studies. One galena from the Opemiska deposit appears to have had uranogenic lead added at 1735–2075 Ma. Three analyses of galena from the Campbell (Merrill) pit are anomalous or indicate they were formed at 162–300 Ma, and it is suggested they may have resulted from multiple episodic additions of ambient rock lead to galena originally deposited at about 2200 Ma.Two new analyses, together with four older values, for Mistassini Basin lead occurrences define a possible secondary isochron that may indicate an integrated source age of 2655 or 2940 Ma at mineralization ages of 2100 and 1700 Ma, respectively. This secondary isochron is very poorly defined because three other new analyses plot above the line.This study suggests that further geochronological investigation of the Cu–Au orebodies, and of felsic dykes that occur in many cases in close spatial association with them, should be undertaken.

Mineral Deposits of Myanmar (Burma)

10.5382/gb.62 ◽  
2021 ◽  
Author(s):  
Laurence Robb ◽  
Andrew Mitchell
Keyword(s):  
Massive Sulfide ◽  
Gold Deposits ◽  
Late Triassic ◽  
Mineral Deposits ◽  
Magmatic Arc ◽  
Silver Deposits ◽  
Copper Gold ◽  
Lead Zinc ◽  
Lead Nickel ◽  
Complex Geology

Myanmar is richly endowed in natural resources that include tin, tungsten, copper, gold, zinc, lead, nickel, and silver, as well as gemstones. The material covered over a nine-day field trip explores the country’s complex geology, which reflects a collisional history stretching from the Late Triassic to at least Miocene, sited at the eastern end of the India-Asia suture. The country can be divided into three principal metallotects: the Wuntho-Popa magmatic arc, with granites and associated porphyry-type and epithermal Cu-Au mineralization; the Slate Belt (also called the Mogok-Mandalay-Mergui Belt), with multiple precollisional I-type and postcollisional S-type crustal melt granites that host significant tin-tungsten mineralization, and which also are host to a number of orogenic gold deposits; and the Shan Plateau with massive sulfide-type and also MVT-style lead-zinc-silver deposits.

Osmium Isotope Constraints on Ore Metal Recycling in Subduction Zones

Science ◽  
1999 ◽  
Vol 286 (5439) ◽  
pp. 512-516 ◽  
Author(s):  
Brent I. A. McInnes ◽  
Jannene S. McBride ◽  
Noreen J. Evans ◽  
David D. Lambert ◽  
Anita S. Andrew
Keyword(s):  
Subduction Zones ◽  
Source Region ◽  
Mantle Peridotite ◽  
Gold Deposits ◽  
Advective Transport ◽  
Tectonic Processes ◽  
Metal Recycling ◽  
Copper Gold ◽  
Primary Origin ◽  
Osmium Isotope

Veined peridotite xenoliths from the mantle beneath the giant Ladolam gold deposit on Lihir Island, Papua New Guinea, are 2 to 800 times more enriched in copper, gold, platinum, and palladium than surrounding depleted arc mantle. Gold ores have osmium isotope compositions similar to those of the underlying subduction-modified mantle peridotite source region, indicating that the primary origin of the metals was the mantle. Because the mantle is relatively depleted in gold, copper, and palladium, tectonic processes that enhance the advective transport and concentration of these fluid soluble metals may be a prerequisite for generating porphyry-epithermal copper-gold deposits.

Chapter 1: Gold Deposit Types: An Overview

2020 ◽  
pp. 1-28
Author(s):  
Richard H. Sillitoe
Keyword(s):  
Gold Deposit ◽  
Unknown Origin ◽  
Mafic Magma ◽  
Massive Sulfide ◽  
Gold Deposits ◽  
Hydrothermal Fluids ◽  
Copper Gold ◽  
Deposit Type ◽  
Ambient Surface

Abstract Gold is either the only economically important metal or a major by-product in 11 well-characterized deposit types—paleoplacer, orogenic, porphyry, epithermal, Carlin, placer, reduced intrusion related, volcanogenic massive sulfide (VMS), skarn, carbonate replacement, and iron oxide-copper-gold (IOCG), arguably more than for those of any other metal; it also dominates a number of deposits of uncertain or unknown origin. Major gold concentrations formed worldwide from the Mesoarchean to the Pleistocene, from Earth’s surface to midcrustal paleodepths, alone or in association with silver, base metals, and/or uranium, and from hydrothermal fluids of predominantly metamorphic, magmatic, meteoric, seawater, or, uncommonly, basinal origins, as well as from mafic magma or ambient surface water. Most of the Neoproterozoic and Phanerozoic deposits unequivocally formed in accretionary orogens. As an introduction to this compilation of the world’s major gold deposits and provinces, this paper provides a thumbnail sketch of each gold deposit type, including geologic and economic characteristics and widely accepted genetic models, as well as briefly discusses aspects of their spatial and temporal associations and distributions.

Studi Awal Geologi di Daerah Beruang Kanan Kabupaten Gunung Mas Propinsi Kalimantan Tengah

PROMINE ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 1-11
Author(s):  
Retno Anjarwati ◽  
Arifudin Idrus ◽  
Lucas Donny Setijadji
Keyword(s):  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Gold Deposits ◽  
Central Kalimantan ◽  
Magmatic Arc ◽  
Tertiary Sediment ◽  
Copper Gold ◽  
Regional Tectonic ◽  
Mineralization Processes ◽  
High Yields

The regional tectonic conditions of the KSK Contract of Work are located in the mid-Tertiary magmatic arc (Carlile and Mitchell, 1994) which host a number of epithermal gold deposits (eg, Kelian, Indon, Muro) and significant prospects such as Muyup, Masupa Ria, Gunung Mas and Mirah. Copper-gold mineralization in the KSK Contract of Work is associated with a number of intrusions that have occupied the shallow-scale crust at the Mesozoic metamorphic intercellular junction to the south and continuously into the Lower Tertiary sediment toward the water. This intrusion is interpreted to be part of the Oligocene arc of Central Kalimantan (in Carlile and Mitchell 1994) Volcanic rocks and associated volcanoes are older than intrusions, possibly aged Cretaceous and exposed together with all three contacts (Carlile and Mitchell, 1994) some researchers contribute details about the geological and mineralogical background, and some papers for that are published for the Beruang Kanan region and beyond but no one can confirm the genesis type of the Beruang Kanan region The mineralization of the Beruang Kanan area is generally composed by high yields of epithermal sulphide mineralization. with Cu-Au mineralization This high epithermal sulphide deposition coats the upper part of the Cu-Au porphyry precipitate associated with mineralization processes that are generally controlled by the structure

scholarly journals Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

Geosciences ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Pavel Kepezhinskas ◽  
Nikolai Berdnikov ◽  
Nikita Kepezhinskas ◽  
Natalia Konovalova
Keyword(s):  
Subduction Zones ◽  
Far East ◽  
Gold Deposits ◽  
Type I ◽  
Isotopic Signatures ◽  
Epithermal Mineralization ◽  
Depleted Mantle ◽  
Mantle Sources ◽  
East Russia ◽  
Collisional Orogens

Adakites are Y- and Yb-depleted, SiO2- and Sr-enriched rocks with elevated Sr/Y and La/Yb ratios originally thought to represent partial melts of subducted metabasalt, based on their association with the subduction of young (<25 Ma) and hot oceanic crust. Later, adakites were found in arc segments associated with oblique, slow and flat subduction, arc–transform intersections, collision zones and post-collisional extensional environments. New models of adakite petrogenesis include the melting of thickened and delaminated mafic lower crust, basalt underplating of the continental crust and high-pressure fractionation (amphibole ± garnet) of mantle-derived, hydrous mafic melts. In some cases, adakites are associated with Nb-enriched (10 ppm < Nb < 20 ppm) and high-Nb (Nb > 20 ppm) arc basalts in ancient and modern subduction zones (HNBs). Two types of HNBs are recognized on the basis of their geochemistry. Type I HNBs (Kamchatka, Honduras) share N-MORB-like isotopic and OIB-like trace element characteristics and most probably originate from adakite-contaminated mantle sources. Type II HNBs (Sulu arc, Jamaica) display high-field strength element enrichments in respect to island-arc basalts coupled with enriched, OIB-like isotopic signatures, suggesting derivation from asthenospheric mantle sources in arcs. Adakites and, to a lesser extent, HNBs are associated with Cu–Au porphyry and epithermal deposits in Cenozoic magmatic arcs (Kamchatka, Phlippines, Indonesia, Andean margin) and Paleozoic-Mesozoic (Central Asian and Tethyan) collisional orogens. This association is believed to be not just temporal and structural but also genetic due to the hydrous (common presence of amphibole and biotite), highly oxidized (>ΔFMQ > +2) and S-rich (anhydrite in modern Pinatubo and El Chichon adakite eruptions) nature of adakite magmas. Cretaceous adakites from the Stanovoy Suture Zone in Far East Russia contain Cu–Ag–Au and Cu–Zn–Mo–Ag alloys, native Au and Pt, cupriferous Ag in association witn barite and Ag-chloride. Stanovoy adakites also have systematically higher Au contents in comparison with volcanic arc magmas, suggesting that ore-forming hydrothermal fluids responsible for Cu–Au(Mo–Ag) porphyry and epithermal mineralization in upper crustal environments could have been exsolved from metal-saturated, H2O–S–Cl-rich adakite magmas. The interaction between depleted mantle peridotites and metal-rich adakites appears to be capable of producing (under a certain set of conditions) fertile sources for HNB melts connected with some epithermal Au (Porgera) and porphyry Cu–Au–Mo (Tibet, Iran) mineralized systems in modern and ancient subduction zones.

Gold Exploration and Potential of the Appalachian Piedmont of Eastern Alabama

SEG Discovery ◽  
2013 ◽  
pp. 1-17
Author(s):  
Jim Saunders ◽  
Mark Steltenpohl ◽  
Robert B. Cook
Keyword(s):  
Massive Sulfide ◽  
Gold Deposits ◽  
Southern Appalachians ◽  
Sulfide Deposits ◽  
Gold Exploration ◽  
Geochemical Association ◽  
Carolina Slate Belt ◽  
Appalachian Piedmont ◽  
Metamorphic Terranes ◽  
Exploration Activity

ABSTRACT: The discovery and production of gold from epithermal and volcanogenic massive sulfide deposits in the Carolina slate belt of the southern Appalachians perhaps have overshadowed the gold potential of orogenic gold deposits in relatively higher grade metamorphic terranes of the southern Appalachian Piedmont. There has been a limited amount of exploration in the non-Carolina slate belt southern Appalachians since the early 1980s. Here we describe some of the recent exploration activity and geology of gold occurrences in the most productive part of the Alabama Piedmont, including the Goldville and Devil’s Backbone districts. In this area, there is a strong geochemical association of gold and arsenic in bedrock, saprolite, and soils, which reflects the mineralogical association of gold with arsenian pyrite and arsenopyrite in mineralized zones.

Stable isotopes and fluid inclusion constraints on the fluid evolution in the Bacaba and Castanha iron oxide-copper-gold deposits, Carajás Mineral Province, Brazil

2020 ◽  
Vol 126 ◽  
pp. 103738 ◽  
Author(s):  
André Luiz Silva Pestilho ◽  
Lena Virgínia Soares Monteiro ◽  
Gustavo Henrique Coelho de Melo ◽  
Carolina PenteadoNatividade Moreto ◽  
Caetano Juliani ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Iron Oxide ◽  
Fluid Inclusion ◽  
Gold Deposits ◽  
Carajás Mineral Province ◽  
Fluid Evolution ◽  
Copper Gold

Laterally extensive modified placer gold deposits in the Paleoproterozoic Mississagi Formation, Clement and Pardo Townships, Ontario

2011 ◽  
Vol 48 (5) ◽  
pp. 779-792 ◽  
Author(s):  
D.G.F. Long ◽  
T. Ulrich ◽  
B.S. Kamber
Keyword(s):  
Massive Sulfide ◽  
Gold Deposits ◽  
Low Flow ◽  
Braided Rivers ◽  
Valley Fill ◽  
Potential Source ◽  
Lake Formation ◽  
Lateral Extent ◽  
Topographic Relief ◽  
Depositional Elements

Local gold concentrations are found in laterally extensive pyrite-bearing, framework-supported, cobble and boulder conglomerates in the basal 30 m of the Mississagi Formation in the south eastern part of the Huronian outcrop belt. These were deposited as part of a valley-fill succession, in shallow gravel-bed braided rivers with local hyperconcentrated flows. The basal contact with underlying Archean psammites is typically highly irregular and shows no obvious sign of weathering suggesting that deposition took place soon after retreat of the glaciers responsible for deposition of the Ramsey Lake Formation. Highest gold concentrations are associated with moderately well-sorted medium to large pebble conglomerate that show some signs of reworking during low flow events. Depositional elements are typically lenticular and of limited lateral extent. Unlike the older pyritic quartz-pebble conglomerates at the base of the Matinenda Formation in the Elliot Lake and Blind River areas, these conglomerates contain no uraninite and are polymict with material derived from a highly restricted catchment area with marked local and regional topographic relief. Porous detrital allogenic pyrite and euhedral post-depositional pyrite have overlapping, generally positive δ34S values, indicating a closed system during diagenesis and metamorphism. The presence of biotite-enriched rims on many of the metavolcanic and metasedimentary clasts in the conglomerates suggests that gold was partly leached from the allogenic pyrite grains at the peak of the Penokean Orogeny at 1.85–1.5 Ga. The potential source of the Au-bearing detrital allogenic pyrite appears to be an as yet undiscovered Archean volcanic-hosted massive sulfide (VHMS) deposit located 1 to 8 km north of the deposit.

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