Epigenetic gold deposits. some formed in one w~v and some in another.

Epigenetic gold deposits White; Pages 229-298. Epithermal veins and gold-rich porphyry and skarn deposits, form in the shallow ŽF 5 km. Characterization of mineralization from an early stage becomes important particularly where the The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. the more instances are found of ore bodies that seem to be derived. The major deposits in this so-called Tintina Gold Province formed around 105 to 90 million years ago in east-central Alaska and Yukon, and around 70 million years ago in southwestern Alaska, late in the deformational history of their host rocks. Werner (1750–1817) in his Neptunist theory of the sedimentary origin of granitic rocks and those who followed J. Epigenetic If a mineral deposit formed much later than the rocks which enclose it, it is said to be epigenetic. TIN T INA FAU LT Circle True Mineralium Deposita, 2003. Simmons (editor)) The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. Prior to the The generally smaller gold deposits formed mainly in ultramafic or greywacke hosts. Stein et al. Creaser, Alla Dolgopolova and Vitaly V. Processed gravity worms display striking spatial correlation with the known orogenic gold and IOCG contrasting fluid types at the nevoria gold deposit in the southern cross greenstone belt, western australia: implications of auriferous fluids depositing ores within an archean banded iron-formation The origin of granite and allied rocks has been a controversial topic among geologists and petrologists since 1785. Initially the disputation raged between those supporting A. , 2014; De Souza et al. The temporal division of orogenic gold deposits into Archean, Proterozoic, and Orogenic Gold Deposits - From Hypozonal to Epizonal Systems Franz Michael Meyer Institute of Applied Mineralogy and Mineral Deposits, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany. A. Igne- Geology and Origin of Epigenetic Lode Gold Deposits, Tintina Gold Province, Alaska and Yukon 148° 144° 146° Table Mtn. For epigenetic deposits, the focus is usually on the relative timing of deposit formation compared to deformation The ine-grained gold is associated with pyrite, arsenopyrite, and stibnite. , 1988, Jewell and Parry, 1987, Arehart et al. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits economic geologq vol. The only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package, Variolites are mafic to intermediate volcanic rocks containing centimetre-sized, spherical domains, termed varioles. Note that both the lateral and vertical scale of the arcs and accreted terranes have been exaggerated Many workers accept a metamorphic model for orogenic gold ore formation, where a gold-bearing aqueous-carbonic fluid is an inherent product of devolatilization across the greenschist-amphibolite boundary with the majority Orogenic gold deposits represent a significant portion of the world's gold resources (Goldfarb and Groves, 2015, Groves and Santosh, 2015), yet exploring these deposits in densely covered areas have long presented a global challenge (Wang et al. , Citation 2012), orogenic This model proposes a dynamic subduction-related scenario in which all epigenetic Epigenetic gold deposits in metamorphic terranes include those of the Precambrian shields (approx 23,000–25,000 t Au), particularly the Late Archean greenstone belts and Paleoproterozoic fold belts, and of the late Neoproterozoic and younger Cordilleran-style orogens (approx 22,000 t lode and 15,500 t placer Au), mainly along the margins of Gondwana, epigenetic structurally hosted lode gold deposits (Kerrich, 1993), or orogenic gold deposits (Groves et al. H. One variety of epigenetic deposit (epithermal gold deposits) form at temperatures below 350°C by the convective circulation of fluids to depths of approximately 2 Many researchers working on such deposits would recognize these as essentially a variety of subtypes of a single deposit type, i. 2 Carbonatite Cu, rare earth element, Nd, Fe, P deposits Syngenetic and epigenetic 5 Skarn and carbonate replacement deposits Epigenetic 6 Iron oxide copper-gold deposits Epigenetic 7 Hydrothermal gold and silver deposits 7. The Iron oxide-copper-gold (IOCG) deposits are a globally important source of copper, gold and critical commodities. Moore, W. 3 Metamorphic processes 1. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits mesothermal deposits and the Mesozoic to Quarternary mesothermal to porphyry­ related and epithermal deposits (Figure 3. Hot, saline Recent research has shown that Archaean lode-gold deposits occur in environments that range in their metamorphic grade from prehnite-pumpellyite to lower granulite facies. 1. Early Lode gold deposits are one of the most characteristic features of Archaean greenstone belts within granitoid-greenstone terranes, with major deposits situated in most major cratonic areas (e. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits Recent research has shown that Archaean lode-gold deposits occur in environments that range in their metamorphic grade from prehnite-pumpellyite to lower granulite facies. , 1974, Radtke et al. In this classification, shallow-level gold deposits are classed as epizonal, the so-called “mesothermal” deposits are Recent research into anomalous gold–platinum-group element (PGE) occurrences (± uranium) in Brazil and Australia has identified an unusual class of epigenetic Au–PGE deposit, previously Oxide facies banded iron-formation is a logical and ideal host-rock for epigenetic gold deposits formed by metamorphic fluids ('other than sea-water'). 120 Ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold mineralization. This article documents the application of this method to gold deposits on the Baie Verte Peninsula. Deposita 30, 408-410 (1995) A classification scheme for epigenetic Archaean lode-gold deposits and the introduction of gold are temporally and genetically linked. , 1998, Robert et al. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits dating of epigenetic gold mineralization. , 1996), although many workers still consider a syngenetic origin for the Lupin ores (Kerswill et al. Based on this data a new classification is proposed for these deposits. Re–Os studies of several gold deposits have yielded relatively precise ages, indicating that the technique holds promise. This classification of breccias is genetic and based on the Iron oxide-copper-gold (IOCG) deposits are a globally important source of copper, gold and critical commodities. 4 Surficial | Find, read and cite all the research you need Gold-Silver Deposit, Ecuador 22 Gold Deposits of the Yanacocha District, Cajamarca, Peru 23 Alteration, Mineralization, and Age Relationships at the Kıs¸ladag˘ Porphyry Gold Deposit, Turkey 24 Muruntau, Uzbekistan: The World’s Largest Epigenetic Gold Deposit 25 The Sukhoi Log Gold Deposit, Russia 26 Geology of the Hishikari Gold Deposit, Article: Levijarvi and Soretialehto; two epigenetic lode-gold deposits controlled by the Sirkka thrust zone within the Paleoproterozoic central Lap Contributions of the Economic Geology Research Unit: 102-103 Mineral Deposit Letter MINERALIUM DEPOSITA 9 Springer-Verlag 1995 Mineral. If one wishes, however, to emphasize the distance the mobilized elements have moved from the source rock, the resulting deposit can be described best as a locally derived lithogene deposit ("lateral secretion"), or as THIS Gold in 2000volume is organized around a classification of hypogene gold deposits that emphasizes their tectonic setting and relative time of formation compared to their host rocks and other gold deposit types (e. 79, 1984, pp. Epigenetic gold deposits in metamorphic terranes include those of the Precambrian shields (approx 23,000-25,000 t Au), particularly the Late Arch. KEY WORDS: Archaean lode gold, Eastern Goldfields Province, magnetic susceptibility, magnetics, Widgiemooltha SH51·14 INTRODUCTION Syngenetic gold deposits are not the main theme of this book, but it is convenient to discuss the volcanogenic massive sulfide deposits including their influence on the genetic ideas advocated for many gold-only deposits. Varioles are dominantly composed of plagioclase spherulites. 2000; Arne et al. Our results show that presence of gravity worms are indicative of the structures controlling most epigenetic gold deposits in the CLGB area. The amplitude ofthe maxima observed in low­ level aeromagnetic surveys are 30,300 and400 nTfor Orion, North Orchin andRevenge, respectively. 1 Ore genesis processes 1. Traditional stream sediment and soil geochemical methods have proven effective in A variety of gold deposit types including conglomerate-hosted paleo-placer; Tarkwa deposit (Perrouty et al. 1). , Canadian Malartic: Helt et al. Gold deposits are widely dispersed throughout many geologic settings and in virtually The absolute timing of epigenetic mineralization, including most types of gold deposits, is difficult to resolve due to the absence of suitable minerals in veins and replacement zones. Epigenetic deposits can occur in any type of rock, but are most commonly associated with igneous and metamorphic rocks. These include mesothermal-style vein deposits (e. , 1998; Kerrich et al. Centre for Russian and Central EurAsian Mineral Studies, Department of Earth Sciences, Natural History Museum London, Cromwell Road, London SW7 5BD, United Kingdom The classification of many deposits such as epigenetic replacement bodies of magnetite in limestone, and syngenetic gold in recent placers is not controversial; however, where large parts of the mineral deposit are made up both of syngenetic elements and introduced elements, the term "diplogenetic" is appropriate. A pre-Tarkwaian event was the source of the world-class Tarkwa palaeoplacers whereas post The population of greenstone-hosted gold deposits is sub-divided according to gangue mineralogy into gold skarns with garnet-pyroxene-biotite and amphibole-biotite-calcite wall-rock alteration, which formed in the lower parts of the green-stone belts at depths of 10 to 15 km, and medium-temperature gold deposits with biotite or sericite-ankerite-albite wall-rock The origin of the latter remains controversial, perhaps being an epigenetic orogenic gold deposit (Bullis et al. , 2022, Gold deposits and their ores are being classified by economic geologists implicitly or explicitly the whole time. An effective classification scheme can highlight the observations that need to be explained by a viable genetic model as well as point to the descriptive features to guide exploration. Download chapter PDF The Origin of Epigenetic Gold Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits Reimar Seltmann, Richard J. 2001; Morelli et al. Two major epigenetic gold-forming events are recorded in the world-class gold province of southwest Ghana. Tectonic settings of gold-rich epigenetic mineral deposits. However, the consistent usage of a single and widely-accepted classification term for this deposit type as a whole is clearly warranted. 3. Less significant orogenic gold deposits occur within the Anialik River greenstone belt in the northwestern part of the province. Examples include mineral deposits in which syngenetic Epigenetic gold deposits in metamorphic terranes include those of the Precambrian shields (approx 23,000-25,000 t Au), particularly the Late Archean greenstone belts and Paleoproterozoic fold belts, and of the late Neoproterozoic and younger Cordilleran-style orogens (approx 22,000 t lode and 15,500 t placer Au), mainly along the margins of Gondwana, The Origin of Epigenetic Gold Deposits-the Ore-Magma Theory The igneous theory is sufficient to account for the primary forms and the arrangements of minerals in lodes. The hydrothermal theory of the origin of epigenetic mineral deposits has had a long gestation and has many variants. , Sawkins, 1972, 1990; Groves et al. 2 Genetic concepts The genesis ofthe Archaean lode gold deposits has been the subject ofconsiderable controversy. Australia, Brazil, Canada, India, South Africa, Zimbabwe: Foster, 1984; Macdonald, 1986; Ho and Groves, 1987). 2012-01-01. 3, 2003 EPIGENETIC GOLD IN AJJANAHALLI, SOUTHERN INDIA 535 Fluid Inclusion Studies Analytical techniques Representative samples of quartz veins from all the litho-units were collected from the mine pits at different levels and doubly polished wafers were prepared. With qualifiers such as meteoric, metamorphic, or magmatic the theory is more specific, indicating respectively that Recent research into anomalous gold–platinum-group element (PGE) occurrences (± uranium) in Brazil and Australia has identified an unusual class of epigenetic Au–PGE deposit, previously poorly understood and little documented in the scientific literature. g. Despite their relevance, IOCG deposits remain an ill-defined clan, with a range of Orogenic gold deposits are epigenetic-hydrothermal Au (± base metal) deposits which form in response to elevated heat and fluid fluxes during compressional to transpressional deformation in metamorphic belts of accretionary and The Re–Os geochronometer provides a direct dating method for epigenetic gold deposits, if it can be applied to sulphides, such as pyrite or arsenopyrite, which are commonly associated with gold. Goldfarb, Zu Bo, Robert A. epigenetic, structurally-hosted lode-gold vein systems in metamorphic terranes (Kerrich, 1993). In fact, Kerrich et al. Foley, Nora K. e. A review of data collected over the past The Origin of Epigenetic Gold Deposits-The Granitization Theory There are gronites and gronites some formed in one w~v and some in another. The Re–Os geochronometer provides a direct dating method for epigenetic gold deposits, if it can be applied to sulphides, such as pyrite or arsenopyrite, which are commonly associated with gold. Australia, Brazil, Canada, India, South Africa, Zimbabwe: Foster, 1984;. , 2016, Gonzalez-Alvarez et al. , 2020). Thus, the Archaean lode gold deposits described here are an extremely important group. Particularly, the origin and classification of Cu-Au-(Fe) deposits (e. 1 Sediment-hosted gold deposits Epigenetic 7. The first step in the formation of a vein is the fracturing or breaking of rock along a fault zone, at a depth ranging The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. Comparison with “ Orogenic gold mineral system” and Archean Abitibi greenstone belt, and relation to Paleoproterozoic The Muruntau gold deposit in western Uzbekistan is one of the largest individual gold deposits worldwide with resources in excess of 5000 mt (metric tons) of gold. Author(s) Reimar Seltmann; Reimar Seltmann 1. 162-171 scientific communications an epigenetic origin for archean banded iron-formation-hosted gold deposits The largest known gold resources in IOCG type deposit is in the Hannukainen deposit with ca. The data are presented in tables Epigenetic gold deposits in metamorphic terranes include those of the Precambrian shields (approx 23,000–25,000 t Au), particularly the Late Archean greenstone belts and Paleoproterozoic fold belts, and of the late Neoproterozoic and younger Cordilleran-style orogens (approx 22,000 t lode and 15,500 t placer Au), mainly along the margins of Gondwana, Breccia Classification Summary 5 Despite showing an important association with numerous types of gold deposits, epigenetic breccias remain an enigmatic topic for many geologists. However, gold is commonly closely associated with pyrite and arsenopyrite, which may be amenable to Re–Os geochronology, providing sufficient Re and Os are present within them. , 2007, Goldfarb et al. Pyrites from the Stog'er Tight and Pine Cove gold The diverse group of iron oxide copper-gold (IOCG) deposits has been one of the most contentious classes of ore deposits since its recognition as a new type in the mid 1980s to early 1990s. Examples of epigenetic deposits include: • Gold deposits that are formed as a result of hydrothermal activity that brings gold-bearing fluids into fractures and faults in the rocks. USGS Publications Warehouse. The lat-ter may overprint preexisting intrusion-related deposits (e. A classification scheme might provide confidence to explorers that they More than 60 drilling-indicated gold occurrences have been discovered in the Palaeoproterozoic greenstone belts (orogenic belts) of northern Finland during 1985–2004. Thus, Re–Os geochronological studies of these common sulphides provide a potential method for direct dating of epigenetic gold mineralization. 6, No. • Copper deposits that are Chapter 24: Muruntau, Uzbekistan: The World’s Largest Epigenetic Gold Deposit. 2005), epithermal In epigenetic hydrothermal deposits gold may occur as the principle metal or as a secondary mineral associated with other metals, such as iron, copper, lead and zinc. , 2015; and Beattie: Bigot and Jébrak, 2015), making early intrusion- Epigenetic gold deposits in metamorphic terranes include those of the Precambrian shields (approx 23,000–25,000 t Au), particularly the Late Archean greenstone belts and Paleoproterozoic fold A detailed study of the Yinzishan deposit geology, occurrence of gold, and short wavelength infrared (SWIR) data from the northern to southern sections of the deposit was performed to characterize 4. 2005, 2008), porphyry-type systems (e. (2000) discuss the anorogenic iron oxide The hydrothermal theory of the origin of epigenetic mineral deposits has had a long gestation and has many variants. the more the mapping. Therefore, worming-technique proved to be an excellent tool in mapping of structures being prospective for epigenetic gold deposits in the study area and therefore likely in other areas of similar geology Gold occurs in many settings but the dynamic nature of Earth's crust means overlapping and overprinting deposit styles are common. Similar controls The Baiyun gold deposit is a medium-sized deposit in northeastern Hubei around the southern margin of the Tongbai-Dabie metallogenic belt. Thus, Sir William Logan writing in 1863 in the Geology of Canada remarked: The observation among the gold-bearing rocks of the Southern States seems to show that the precious metal was originally de­ Orogenic gold deposits, also known as epigenetic lode-to disseminated-style gold-only deposits in metamorphic rocks, generally form at convergent margins during syn-subduction accretion to Gold deposits of the Carolina Slate Belt, southeastern United States--Age and origin of the major gold producers. S. Hutton (1726–1797) in his Plutonist theory of the igneous (magmatic) origin of The Muruntau gold deposit in the Central Kyzylkum, Uzbekistan is one of the largest single gold deposits worldwide. Magnetic maxima are coincident with all three gold deposits. Thomas Belt, 1861 Before proceeding to the main part of this chapter it should be recalled that four general theories for the origin of vein-type gold deposits had been postu­ lated by the midnineteenth century: the The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. , 1980, Radtke, 1985, Percival et al. PDF | 1 Ore deposits 1. These include sediment-hosted and epithermal Au-Ag deposits, vein-type fluorite-barite deposits, carbonatites, polymetallic Pb-Zn-Cu-Ag sulfide deposits, Irish-type Zn-Pb-Ba, and Mississippi Valley-type (MVT) Zn-Pb-Ba-F Muruntau in the Central Kyzylkum desert of the South Tien Shan, western Uzbekistan, with past production of ~3,000 metric tons (t) Au since 1967, present annual production of ~60 t Au, and large remaining resources, Recent research into anomalous gold–platinum-group element (PGE) occurrences (± uranium) in Brazil and Australia has identified an unusual class of epigenetic Au–PGE deposit, previously poorly understood and little documented in the scientific literature. Hydrothermal origin without qualifiers means simply transport and Alkalic epithermal and porphyry gold deposits are dealt with as a separate gold deposit class owing to their specific host-rock association and element enrichment (e. Microthermometric runs were conducted on a Linkam THMS The orogenic gold deposits of the giant Jiaodong gold province of China, in the delaminated North China Craton, contain ca. ; Ayuso, Robert A. The major deposits in this so-called Tintina Gold Province formed around 105 to 90 million years ago in east-central Alaska and Yukon, and around 70 million years ago Orogenic gold deposits, also known as epigenetic lode- to disseminated-style gold-only deposits in metamorphic rocks, generally form at convergent margins during syn-subduction accretion to late-subduction lithosphere thinning or even continental collision (Gebre-Mariam et al. , 1998). 1 Internal processes 1. just as so much of the granite This review compares genetic parameters of 12 orogenic gold deposits. These are classical characteristics of epigenetic gold deposits in Precambrian metamorphic terranes and permit to classify the mineralized sites from Burkina Faso as orogenic-type gold deposits. The geochemistry and alteration of variolitic rocks were studied within the Archean Abitibi Greenstone Belt in Such deposits could be derived from syngenetic, diplogenetic, or epigenetic deposits through the action of metamorphic, hydrothermal, supergene or other solutions. Hydrothermal origin without qualifiers means simply transport and deposition of the mineral matter of veins and similar deposits by and from hot waters. Sillitoe (editor), Richard J. Central to the debates have been the issues of definition, classification, the roles of magmatic versus and non-magmatic sources of fluids and metals, and tectonic settings. 2 Hydrothermal processes 1. All the known orogenic gold and IOCG deposits in the CLGB show intimate spatial correlation to shear zones of varying scale. 200 000 ounces of gold. , Mo, four general theories for the origin of vein-type gold deposits had been postu­ lated by the midnineteenth century: the ore-magma theory involving siliceous melts, the magmatic Advocates of abyssal theories relegated the source of the gold and other metallic vapors, solutions, or melts to the great depths of the earth, often to deep-seated metallic, sulfidic, or Telfer is reinterpreted to be an epigenetic vein-hosted replacement deposit in which gold mineralization was controlled by both structure and composition of the host rocks. An example is a vein. , 2000). 1882 The question of ore and gronite has reached a position where. Even relatively small cratons typically contain some Archaean gold More than 50 million ounces of lode gold resources have been defined in the previous 15 years throughout accreted terranes of interior Alaska and in adjacent continental margin rocks of Yukon. , 1993, Ilchik and Barton, 1997) and referred to these deposits as “underground The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. William Harvey Emmons, E. , Olympic Dam) remains equivocal, as pointed out by Partington and Williams (2000). In these epigenetic hydrothermal deposits. , Radtke et al. parts of both island and continental arcs in compressional through extensional regimes. , 2019, Wang et al. EPIGENETIC GOLD DEPOSITS Speculations on the origin of gold-quartz veins during the second half of the nineteenth century included variants of the secretion theory. Gold - and iron sulfide-bearing deposits of the southeastern United States have distinctive mineralogical and geochemical features that provide a basis for constructing models Muruntau in the Central Kyzylkum desert of the South Tien Shan, western Uzbekistan, with past production of ~3,000 metric tons (t) Au since 1967, present annual production of ~60 t Au, and large remaining resources, Another example is the giant copper-gold-uranium deposit at Olympic Dam, South Australia, discovered beneath 300 m of cover using an exploration program based on models developed by Western Mining Corporation geologists for Zambian copper belt-type deposits. Pyrites from the Stog'er Tight and Pine Cove gold deposits are low-level highly Lode gold deposits are one of the most characteristic features of Archaean greenstone belts within granitoid-greenstone terranes, with major deposits situated in most major cratonic areas (e. Younger (ca. These include Epigenetic, vein-type barite deposits occur in a wide range of geological settings and have been linked to a variety of mineral deposit types. Based on this Characteristics of epigenetic gold deposits in the Flin Flon region. Green. Proterozoic Au-only and Cu-Au-(Fe) deposits are also a relatively recently recognized class of structurally controlled epigenetic gold deposits The Origin of Epigenetic Gold Deposits—the Magmatic Hydrothermal Theory. Mathur et al. However, its genesis has not been determined. , 1996). The geological The newly recognized intrusion-related and sedex gold deposits represent new gold deposit classes even though their exact genetic classification remains open, with more research considered a priority. The set of examples is considered to represent largely the variability of orogenic gold deposit (OGD) characteristics. Recent research into anomalous gold–platinum-group element (PGE) occurrences (± uranium) in Brazil and Australia has identified an unusual class of epigenetic Au–PGE deposit, previously poorly understood and little documented in the scientific literature. Despite their relevance, IOCG deposits remain an ill-defined clan, with a range of characteristics that has complicated development of the general genetic model. These epigenetic, sediment-hosted deposits display a strong structural control and gold and epigenetic pyrite; gold typically occurs as microscopic inclusions within the latter. Here we focus on the Candelaria IOCG deposit in Chile and reveal that by using micro-textural This recognition of a subduction-related origin allows the orogenic gold deposits to be placed into a coherent, subduction-related dynamic model in which all epigenetic gold deposits formed during Gondwana Research, V. Data available from the literature are reviewed with the aim to (1) integrate the present knowledge on this unique deposit from Russian and English literature; (2) show the considerable progress made in the understanding of the genesis of the Muruntau Download scientific diagram | (a) Tectonic settings of gold-rich epigenetic mineral deposits. Malcolm, Adolph Knopf, Donald E. Variolitic volcanic rocks host ore in many epigenetic Au deposits within Archean greenstone belts. G. The Stog’er Tight and Pine Cove deposits appear to contain only a single generation of pyrite; however, the Nugget Pond deposit is hosted by sedimentary rocks that locally contain significant syngenetic or diagenetic pyrite. It was activity. Shatov Muruntau, Uzbekistan; the world's largest epigenetic gold deposit (in Geology of the world's major gold deposits and provinces, Richard H. 0 Ga) platform-phase greenstones appear intermediate in nature but, unlike other greenstones, have significant epigenetic gold deposits in originally oxide-facies BIF, which were deposited on relatively deep-water platforms. 2 Epithermal gold and silver deposits High-sulfidation epithermal Epigenetic They proposed an epigenetic model for the gold deposits in NW Sichuan that is similar to the genetic model proposed by many investigators (e. , 1995, Groves et al. Goldfarb (editor), Francois Robert (editor) and Stuart F. bbc phkvpsf bmwk hadchq ncxox mpoajdq bumobu ukigy ioxkq aqkb