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Francis Chartrand - One of the best experts on this subject based on the ideXlab platform.
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Mineralogy, Geochemistry, and Paragenesis of the Eastern Metals Serpentinite-Associated Ni-Cu-Zn Deposit, Quebec Appalachians
2016Co-Authors: Marne Auclair, Michel Gauthier, Francis ChartrandAbstract:The Eastern Metals deposit, located in the southern Quebec Appalachians, occurs at the contact of a slice of ultramafic rock enclosed within ophiolitic m61ange sediments of Cambro-Ordovician age that are slightly metamorphosed tolower greenschist facies. Disseminated to massive sulfides are hosted by intensely carbonatized and silicified rocks at the sheared contacts between serpentinite and graphitic slate. The deposit comprises two mineralized zones, the Ni-Zn North zone and the Cu-Ni-Zn-Co-Au South zone. Textural and structural evidence suggests hat the deposit formed in two main phases: early alteration and mineraliza-tion in serpentinite; and late main-stage Cu-Ni mineralization. Hydrothermal alteration by CO2-, Ca-, S-, and As-rich fluids during a relatively late stage of serpentinization took place as ophiolite slices were obducted during the Taconic Orogeny. Serpentinite was initially transformed into talc-carbonate schist, and then, in a progressively more oxidizing and lower temperature environment, into listwaenite (quartz-carbonate rock), and finally birbirite (pyrite-bearing siliceous rock). All hydrothermally altered rocks are rich in Cr, Ni, and Co. The presence of relict chromite and ghosts of typical serpentinit
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mineralogy geochemistry and paragenesis of the eastern metals serpentinite associated ni cu zn deposit quebec appalachians
Economic Geology, 1993Co-Authors: Marne Auclair, Michel Gauthier, Jacques Trottier, Michel Jebrak, Francis ChartrandAbstract:The Eastern Metals deposit, located in the southern Quebec Appalachians, occurs at the contact of a slice of ultramafic rock enclosed within ophiolitic melange sediments of Cambro-Ordovician age that are slightly metamorphosed to lower greenschist facies. Disseminated to massive sulfides are hosted by intensely carbonatized and silicified rocks at the sheared contacts between serpentinite and graphitic slate. The deposit comprises two mineralized zones, the Ni-Zn North zone and the Cu-Ni-Zn-Co-Au South zone. Textural and structural evidence suggests that the deposit formed in two main phases: early alteration and mineralization in serpentinite; and late main-stage Cu-Ni mineralization.Hydrothermal alteration by CO 2 -, Ca-, S-, and As-rich fluids during a relatively late stage of serpentinization took place as ophiolite slices were obducted during the Taconic Orogeny. Serpentinite was initially transformed into talc-carbonate schist, and then, in a progressively more oxidizing and lower temperature environment, into listwaenite (quartz-carbonate rock), and finally birbirite (pyrite-bearing siliceous rock). All hydrothermally altered rocks are rich in Cr, Ni, and Co. The presence of relict chromite and ghosts of typical serpentinite net texture confirms the ultramafic nature of the protolith. The isotopic compositions of carbonate (delta 13 C = -2.4 to -7.0ppm) suggest a juvenile source of carbon, whereas sulfur isotopes from pyrite (delta 34 S = 7 to 19ppm) indicate interaction between seawater or meteoric water from sedimentary country rock.Late main-stage copper and nickel sulfides replace early pyrite. The sulfide assemblage in the North zone, comprising pyrite, violarite-polydymite, and millerite, is compatible with maximum temperatures of formation of 356 degrees and 282 degrees C. Massive sulfides in the South zone are composed principally of pyrite and chalcopyrite. Cubanite exsolutions in chalcopyrite indicate a minimum temperature of formation of approximately 250 degrees C. Gold, present in the South zone only, exhibits good positive correlations with lead, arsenic, antimony, and mercury. Metal zonation in the Eastern Metals deposit developed in response to changes in the redox potential in the host-rock environment.This deposit provides a unique opportunity to study a polymetallic serpentinite-associated deposit which has not been significantly overprinted by supergene alteration, intense metamorphism, or tectonic fabrics that occur in other examples of this deposit class such as Bou Azzer in Morocco or Outokumpu in Finland.
Francis A Macdonald - One of the best experts on this subject based on the ideXlab platform.
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tropical weathering of the Taconic Orogeny as a driver for ordovician cooling
Geology, 2017Co-Authors: Nicholas L Swansonhysell, Francis A MacdonaldAbstract:Author(s): Swanson-Hysell, NL; Macdonald, FA | Abstract: © 2017 Geological Society of America. The Earth's climate cooled through the Ordovician Period leading up to the Hirnantian glaciation. Increased weatherability of silicate rocks associated with topography generated on the Appalachian margin during the Taconic Orogeny has been proposed as a mechanism for Ordovician cooling. However, paleogeographic reconstructions typically place the Appalachian margin within the arid subtropics, outside of the warm and wet tropics where chemical weathering rates are highest. In this study, we reanalyze the paleomagnetic database and conclude that Ordovician constraints from cratonic Laurentia are not robust. Instead, we use paleomagnetic data from well-dated volcanic rocks in the accreting terranes to constrain Laurentia's position given that the Appalachian margin was at, or equatorward of, the paleolatitude of these terranes. To satisfy these allochthonous data, Laurentia must have moved toward the equator during the Ordovician such that the Appalachian margin was within 10° of the equator by 465 Ma. This movement into the tropics coincided with the collision and exhumation of the Taconic arc system, recorded by a shift in neodymium isotope data from shale on the Appalachian margin to more juvenile values. This inflection in detrital neodymium isotope values precedes a major downturn in global seawater strontium isotopic values by more than one million years, as would be predicted from a change in weathering input and the relatively long residence time of strontium in the ocean. These data are consistent with an increase in global weatherability associated with the tropical weathering of mafic and ultramafic lithologies exhumed during the Taconic arc-continent collision. A Taconic related increase in weatherability is a viable mechanism for lowering atmospheric CO2 levels through silicate weathering contributing to long-term Ordovician cooling.
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bridging the gap between the foreland and hinterland ii geochronology and tectonic setting of ordovician magmatism and basin formation on the laurentian margin of new england and newfoundland
American Journal of Science, 2017Co-Authors: Francis A Macdonald, James L. Crowley, Paul Karabinos, Eben Blake Hodgin, Peter W Crockford, J W DelanoAbstract:Ordovician strata of the Mohawk Valley and Taconic allochthon of New York and the Humber margin of Newfoundland record multiple magmatic and basin-forming episodes associated with the Taconic Orogeny. Here we present new U-Pb zircon geochronology and whole rock geochemistry and neodymium isotopes from Early Paleozoic volcanic ashes and siliciclastic units on the northern Appalachian margin of Laurentia. Volcanic ashes in the Table Point Formation of Newfoundland and the Indian River Formation of the Taconic allochthon in New York yield dates between 466.16 ± 0.12 and 464.20 ± 0.13 Ma. Red, bioturbated slate of the Indian River Formation record a shift to more juvenile neodymium isotope values suggesting sedimentary contributions from the Taconic arc-system by 466 Ma. Eight ashes within the Trenton Group in the Mohawk Valley were dated between 452.63 ± 0.06 and 450.68 ± 0.12 Ma. These ashes contain zircon with Late Ordovician magmatic rims and 1.4 to 1.0 Ga xenocrystic cores that were inherited from Grenville basement, suggesting that the parent magmas erupted through the Laurentian margin. The new geochronological and geochemical data are integrated with a subsidence model and data from the hinterland to refine the tectonic model of the Taconic Orogeny. Closure of the Iapetus Ocean by 475 Ma via collision of the peri-Gondwanan Moretown terrane with hyperextended distal fragments of the Laurentian margin is not clearly manifested on the autochthon or the Taconic allochthon other than an increase in sediment accumulation. Pro-foreland basins formed during the Middle Ordovician when these terranes were obducted onto the Laurentian margin. 466 to 464 Ma ashes on the Laurentian margin coincide with a late pulse of magmatism in both the Notre Dame arc in Newfoundland and the Shelburne Falls arc of New England that is potentially related to break-off of an east-dipping slab. Following slab reversal, by 455 Ma, the Bronson Hill arc was established on the new composite Laurentian margin. Thus, we conclude that Late Ordovician strata in the Mohawk Valley and Taconic allochthon of New York and on the Humber margin of Newfoundland were deposited in retro-foreland basins.
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a newly identified gondwanan terrane in the northern appalachian mountains implications for the Taconic Orogeny and closure of the iapetus ocean
Geology, 2014Co-Authors: Francis A Macdonald, James L. Crowley, Juliet Ryandavis, Raymond Coish, Paul KarabinosAbstract:The Taconic and Salinic orogenies in the northern Appalachian Mountains record the closure of the Iapetus Ocean, which separated peri-Laurentian and peri-Gondwanan terranes in the early Paleozoic. The Taconic Orogeny in New England is commonly depicted as an Ordovician collision between the peri-Laurentian Shelburne Falls arc and the Laurentian margin, followed by Silurian accretion of peri-Gondwanan terranes during the Salinic Orogeny. New U-Pb zircon geochronology demonstrates that the Shelburne Falls arc was instead constructed on a Gondwanan-derived terrane preserved in the Moretown Formation, which we refer to here as the Moretown terrane. Metasedimentary rocks of the Moretown Formation were deposited after 514 Ma and contain abundant ca. 535–650 Ma detrital zircon that suggest a Gondwanan source. The Moretown Formation is bound to the west by the peri-Laurentian Rowe belt, which contains detrital zircon in early Paleozoic metasedimentary rocks that is indistinguishable in age from zircon in Laurentian margin rift-drift successions. These data reveal that the principal Iapetan suture in New England is between the Rowe belt and Moretown terrane, more than 50 km farther west than previously suspected. The Moretown terrane is structurally below and west of volcanic and metasedimentary rocks of the Hawley Formation, which contains Laurentian-derived detrital zircon, providing a link between peri-Laurentian and peri-Gondwanan terranes. The Moretown terrane and Hawley Formation were intruded by 475 Ma plutons during peak activity in the Shelburne Falls arc. We propose that the peri-Laurentian Rowe belt was subducted under the Moretown terrane just prior to 475 Ma, when the trench gap was narrow enough to deliver Laurentian detritus to the Hawley Formation. Interaction between peri-Laurentian and peri-Gondwanan terranes by 475 Ma is 20 m.y. earlier than documented elsewhere and accounts for structural relationships, Early Ordovician metamorphism and deformation, and the subsequent closure of the peri-Laurentian Taconic seaway. In this scenario, a rifted-arc system on the Gondwanan margin resulted in the formation of multiple terranes, including the Moretown, that independently crossed and closed the Iapetus Ocean in piecemeal fashion.
Martin Moloney - One of the best experts on this subject based on the ideXlab platform.
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Petrochemistry and hydrothermal alteration within the Tyrone Igneous Complex, Northern Ireland: implications for VMS mineralization in the British and Irish Caledonides
Mineralium Deposita, 2014Co-Authors: Steven P. Hollis, Stephen Roberts, Garth Earls, Richard Herrington, Mark R. Cooper, Stephen J. Piercey, Sandy M. Archibald, Martin MoloneyAbstract:Although volcanogenic massive sulfide (VMS) deposits can form within a wide variety of rift-related tectonic environments, most are preserved within suprasubduction affinity crust related to ocean closure. In stark contrast to the VMS-rich Appalachian sector of the Grampian-Taconic Orogeny, VMS mineralization is rare in the peri-Laurentian British and Irish Caledonides. Economic peri-Gondwanan affinity deposits are limited to Avoca and Parys Mountain. The Tyrone Igneous Complex of Northern Ireland represents a ca. 484–464 Ma peri-Laurentian affinity arc–ophiolite complex and a possible broad correlative of the Buchans-Robert’s Arm belt of Newfoundland, host to some of the most metal-rich VMS deposits globally. Stratigraphic horizons prospective for VMS mineralization in the Tyrone Igneous Complex are associated with rift-related magmatism, hydrothermal alteration, synvolcanic faults, and high-level subvolcanic intrusions (gabbro, diorite, and/or tonalite). Locally intense hydrothermal alteration is characterized by Na-depletion, elevated SiO_2, MgO, Ba/Sr, Bi, Sb, chlorite–carbonate–pyrite alteration index (CCPI) and Hashimoto alteration index (AI) values. Rift-related mafic lavas typically occur in the hanging wall sequences to base and precious metal mineralization, closely associated with ironstones and/or argillaceous sedimentary rocks representing low temperature hydrothermal venting and volcanic quiescence. In the ca. 475 Ma pre-collisional, calc-alkaline lower Tyrone Volcanic Group rift-related magmatism is characterized by abundant non-arc type Fe-Ti-rich eMORB, island-arc tholeiite, and low-Zr tholeiitic rhyolite breccias. These petrochemical characteristics are typical of units associated with VMS mineralization in bimodal mafic, primitive post-Archean arc terranes. Following arc-accretion at ca. 470 Ma, late rifting in the ensialic upper Tyrone Volcanic Group is dominated by OIB-like, subalkaline to alkali basalt and A-type, high-Zr rhyolites. These units are petrochemically favorable for Kuroko-type VMS mineralization in bimodal-felsic evolved arc terranes. The scarcity of discovered peri-Laurentian VMS mineralization in the British and Irish Caledonides is due to a combination of minimal exploration, poor-preservation of upper ophiolite sequences, and limited rifting in the Lough Nafooey arc of western Ireland. The geological and geochemical characteristics of the Tyrone Volcanic Group of Northern Ireland and peri-Gondwanan affinity arc/backarc sequences of Ireland and northwest Wales represent the most prospective sequences in the British and Irish Caledonides for VMS mineralization.
Draut, Amy E. - One of the best experts on this subject based on the ideXlab platform.
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Arc-continent collision and the formation of continental crust: A new geochemical and isotopic record from the Ordovician Tyrone Igneous Complex, Ireland
LSU Digital Commons, 2009Co-Authors: Draut, Amy E., Clift, Peter D., Amato, Jeffrey M., Blusztajn Jerzy, Schouten HansAbstract:Collisions between oceanic island-arc terranes and passive continental margins are thought to have been important in the formation of continental crust throughout much of Earth\u27s history. Magmatic evolution during this stage of the plate-tectonic cycle is evident in several areas of the Ordovician Grampian-Taconic orogen, as we demonstrate in the first detailed geochemical study of the Tyrone Igneous Complex, Ireland. New U-Pb zircon dating yields ages of 493 2 Ma from a primitive mafic intrusion, indicating intra-oceanic subduction in Tremadoc time, and 475 10 Ma from a light rare earth element (LREE)-enriched tonalite intrusion that incorporated Laurentian continental material by early Arenig time (Early Ordovician, Stage 2) during arc-continent collision. Notably, LREE enrichment in volcanism and silicic intrusions of the Tyrone Igneous Complex exceeds that of average Dalradian (Laurentian) continental material that would have been thrust under the colliding forearc and potentially recycled into arc magmatism. This implies that crystal fractionation, in addition to magmatic mixing and assimilation, was important to the formation of new crust in the Grampian-Taconic Orogeny. Because similar super-enrichment of orogenic melts occurred elsewhere in the Caledonides in the British Isles and Newfoundland, the addition of new, highly enriched melt to this accreted arc terrane was apparently widespread spatially and temporally. Such super-enrichment of magmatism, especially if accompanied by loss of corresponding lower crustal residues, supports the theory that arc-continent collision plays an important role in altering bulk crustal composition toward typical values for ancient continental crust. © 2009 Geological Society of London
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Arc–continent collision and the formation of continental crust : a new geochemical and isotopic record from the Ordovician Tyrone Igneous Complex, Ireland
'Geological Society of London', 2008Co-Authors: Draut, Amy E., Clift, Peter D., Amato, Jeffrey M., Blusztajn, Jerzy S., Schouten, Hans A.Abstract:Author Posting. © Geological Society of London, 2009. This is the author's version of the work. It is posted here by permission of Geological Society of London for personal use, not for redistribution. The definitive version was published in Journal of the Geological Society 166 (2009): 485-500, doi:10.1144/0016-76492008-102.Collisions between oceanic island-arc terranes and passive continental margins are thought to have been important in the formation of continental crust throughout much of Earth’s history. Magmatic evolution during this stage of the plate-tectonic cycle is evident in several areas of the Ordovician Grampian-Taconic Orogen, as we demonstrate in the first detailed geochemical study of the Tyrone Igneous Complex, Ireland. New U–Pb zircon dating yields ages of 493 ± 2 Ma from a primitive mafic intrusion, indicating intra-oceanic subduction in Tremadoc time, and 475 ± 10 Ma from a light-rare-earth-element (LREE)-enriched tonalite intrusion that incorporated Laurentian continental material by early Arenig time (Early Ordovician, Stage 2) during arc-continent collision. Notably, LREE enrichment in volcanism and silicic intrusions of the Tyrone Igneous Complex exceeds that of average Dalradian (Laurentian) continental material which would have been thrust under the colliding forearc and potentially recycled into arc magmatism. This implies that crystal fractionation, in addition to magmatic mixing and assimilation, was important to the formation of new crust in the Grampian-Taconic Orogeny. Because similar super-enrichment of orogenic melts occurred elsewhere in the Caledonides in the British Isles and Newfoundland, the addition of new, highly enriched melt to this accreted arc terrane was apparently widespread spatially and temporally. Such super-enrichment of magmatism, especially if accompanied by loss of corresponding lower crustal residues, supports the theory that arc-continent collision plays an important role in altering bulk crustal composition toward typical values for ancient continental crust.This work was supported by the University of Aberdeen. LA-MC-ICPMS dating was conducted at the Arizona LaserChron Center with the assistance of George Gehrels and Victor Valencia and was supported by NSF-EAR 0443387
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Laurentian crustal recycling in the Ordovician Grampian Orogeny: Nd isotopic evidence from western Ireland
LSU Digital Commons, 2004Co-Authors: Draut, Amy E., Cooper, Matthew J., Clift, Peter D., Chew, David M., Taylor, Rex N., Hannigan, Robyn E.Abstract:Because magmatism associated with subduction is thought to be the principal source for continental crust generation, assessing the relative contribution of pre-existing (subducted and assimilated) continental material to arc magmatism in accreted arcs is important to understanding the origin of continental crust. We present a detailed Nd isotopic stratigraphy for volcanic and volcaniclastic formations from the South Mayo Trough, an accreted oceanic arc exposed in the western Irish Caledonides. These units span an arc-continent collision event, the Grampian (Taconic) Orogeny, in which an intra-oceanic island arc was accreted onto the passive continental margin of Laurentia starting at ~475 Ma (Arenig). The stratigraphy corresponding to pre-, syn- and post-collisional volcanism reveals a progression of εNd(t from strongly positive values, consistent with melt derivation almost exclusively from oceanic mantle beneath the arc, to strongly negative values, indicating incorporation of continental material into the melt. Using εNd(t) values of meta-sediments that represent the Laurentian passive margin and accretionary prism, we are able to quantify the relative proportions of continent-derived melt at various stages of arc formation and accretion. Mass balance calculations show that mantle- derived magmatism contributes substantially to melt production during all stages of arc-continent collision, never accounting for less than 21 % of the total. This implies that a significant addition of new, rather than recycled, continental crust can accompany arc-continent collision and continental arc magmatism. © 2004 Cambridge University Press
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Laurentian crustal recycling in the Ordovician Grampian Orogeny : Nd isotopic evidence from western Ireland
'Cambridge University Press (CUP)', 2004Co-Authors: Draut, Amy E., Cooper, Matthew J., Clift, Peter D., Chew, David M., Taylor, Rex N., Hannigan, Robyn E.Abstract:Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Geological Magazine 141 (2004): 195-207, doi:10.1017/S001675680400891X.Because magmatism associated with subduction is thought to be the principal source for continental crust generation, assessing the relative contribution of pre-existing (subducted and assimilated) continental material to arc magmatism in accreted arcs is important to understanding the origin of continental crust. We present a detailed Nd isotopic stratigraphy for volcanic and volcaniclastic formations from the South Mayo Trough, an accreted oceanic arc exposed in the western Irish Caledonides. These units span an arc–continent collision event, the Grampian (Taconic) Orogeny, in which an intra-oceanic island arc was accreted onto the passive continental margin of Laurentia starting at [similar] 475 Ma (Arenig). The stratigraphy corresponding to pre-, syn- and post-collisional volcanism reveals a progression of [varepsilon]Nd(t) from strongly positive values, consistent with melt derivation almost exclusively from oceanic mantle beneath the arc, to strongly negative values, indicating incorporation of continental material into the melt. Using [varepsilon]Nd(t) values of meta-sediments that represent the Laurentian passive margin and accretionary prism, we are able to quantify the relative proportions of continent-derived melt at various stages of arc formation and accretion. Mass balance calculations show that mantle-derived magmatism contributes substantially to melt production during all stages of arc–continent collision, never accounting for less than 21% of the total. This implies that a significant addition of new, rather than recycled, continental crust can accompany arc–continent collision and continental arc magmatism
Marne Auclair - One of the best experts on this subject based on the ideXlab platform.
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Mineralogy, Geochemistry, and Paragenesis of the Eastern Metals Serpentinite-Associated Ni-Cu-Zn Deposit, Quebec Appalachians
2016Co-Authors: Marne Auclair, Michel Gauthier, Francis ChartrandAbstract:The Eastern Metals deposit, located in the southern Quebec Appalachians, occurs at the contact of a slice of ultramafic rock enclosed within ophiolitic m61ange sediments of Cambro-Ordovician age that are slightly metamorphosed tolower greenschist facies. Disseminated to massive sulfides are hosted by intensely carbonatized and silicified rocks at the sheared contacts between serpentinite and graphitic slate. The deposit comprises two mineralized zones, the Ni-Zn North zone and the Cu-Ni-Zn-Co-Au South zone. Textural and structural evidence suggests hat the deposit formed in two main phases: early alteration and mineraliza-tion in serpentinite; and late main-stage Cu-Ni mineralization. Hydrothermal alteration by CO2-, Ca-, S-, and As-rich fluids during a relatively late stage of serpentinization took place as ophiolite slices were obducted during the Taconic Orogeny. Serpentinite was initially transformed into talc-carbonate schist, and then, in a progressively more oxidizing and lower temperature environment, into listwaenite (quartz-carbonate rock), and finally birbirite (pyrite-bearing siliceous rock). All hydrothermally altered rocks are rich in Cr, Ni, and Co. The presence of relict chromite and ghosts of typical serpentinit
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mineralogy geochemistry and paragenesis of the eastern metals serpentinite associated ni cu zn deposit quebec appalachians
Economic Geology, 1993Co-Authors: Marne Auclair, Michel Gauthier, Jacques Trottier, Michel Jebrak, Francis ChartrandAbstract:The Eastern Metals deposit, located in the southern Quebec Appalachians, occurs at the contact of a slice of ultramafic rock enclosed within ophiolitic melange sediments of Cambro-Ordovician age that are slightly metamorphosed to lower greenschist facies. Disseminated to massive sulfides are hosted by intensely carbonatized and silicified rocks at the sheared contacts between serpentinite and graphitic slate. The deposit comprises two mineralized zones, the Ni-Zn North zone and the Cu-Ni-Zn-Co-Au South zone. Textural and structural evidence suggests that the deposit formed in two main phases: early alteration and mineralization in serpentinite; and late main-stage Cu-Ni mineralization.Hydrothermal alteration by CO 2 -, Ca-, S-, and As-rich fluids during a relatively late stage of serpentinization took place as ophiolite slices were obducted during the Taconic Orogeny. Serpentinite was initially transformed into talc-carbonate schist, and then, in a progressively more oxidizing and lower temperature environment, into listwaenite (quartz-carbonate rock), and finally birbirite (pyrite-bearing siliceous rock). All hydrothermally altered rocks are rich in Cr, Ni, and Co. The presence of relict chromite and ghosts of typical serpentinite net texture confirms the ultramafic nature of the protolith. The isotopic compositions of carbonate (delta 13 C = -2.4 to -7.0ppm) suggest a juvenile source of carbon, whereas sulfur isotopes from pyrite (delta 34 S = 7 to 19ppm) indicate interaction between seawater or meteoric water from sedimentary country rock.Late main-stage copper and nickel sulfides replace early pyrite. The sulfide assemblage in the North zone, comprising pyrite, violarite-polydymite, and millerite, is compatible with maximum temperatures of formation of 356 degrees and 282 degrees C. Massive sulfides in the South zone are composed principally of pyrite and chalcopyrite. Cubanite exsolutions in chalcopyrite indicate a minimum temperature of formation of approximately 250 degrees C. Gold, present in the South zone only, exhibits good positive correlations with lead, arsenic, antimony, and mercury. Metal zonation in the Eastern Metals deposit developed in response to changes in the redox potential in the host-rock environment.This deposit provides a unique opportunity to study a polymetallic serpentinite-associated deposit which has not been significantly overprinted by supergene alteration, intense metamorphism, or tectonic fabrics that occur in other examples of this deposit class such as Bou Azzer in Morocco or Outokumpu in Finland.
