Nature and geological targeting is a one day short course to be presented by david groves this october in kalgoorlie w. During this journey which would take gold millions of years to do depending on the river system it will go through several transformations. Maple gold takes fresh look at douay site visit ivanhoe alumni see potential in forgotten gold district in quebec. Prospectivity analysis of orogenic gold deposits in saqez. Sixteen common types of bedrock gold deposits are distinguished from one another and their main geological attributes are. A proposed classification in the context of their crustal distribution and relationship to other gold deposit types author links open overlay panel d. Constraints 4 from textures, trace elements and sulfur isotopes of 5 pyrite and marcasite, and raman spectroscopy of 6 carbonaceous material 7 8 yafei wu, 1,2,3 jianwei li, 31,3 katy evans, 2 alan e. A carbonaceous sedimentary sourcerock model for carlin. This presentation attempts to provide the basis of a systematic framework for targeting high grade oreshoots within gold deposits most of these concepts will also be relevant to other hydrothermal ore deposits. These deposits form in response to major orogenic events caused by accretion or changes in subduction direction or dip.
He explains how orogenic gold formed during plate tectonic collisions and. This study presents data on the geological setting and ore mineralogy of these deposits. Smith2 abstract mines in the oatman mineralized district, near oatman in northwestern arizona, have produced more than 1. Some geologists think these deposits were formed when streams deposited the gold into an. Predictive targeting in australian orogenicgold systems. Ore bodies at the deposit include laminated quartz veins and disseminated pyritebearing mylonite. Various theories of ore genesis explain how the various types of mineral deposits. The objectives of this paper are to provide an update on gold deposit models, and what new approaches and techniques can now be used to find gold deposits. Orogenic definition of orogenic by the free dictionary. The model presented here challenges three current views related to orogenic gold deposits. Gold mineralisation stage fluids range from magmatic to dominantly magmatic with variable amounts of external or unexchanged waters, probably introduced into the hydrothermal system during cooling.
In the above orogens, isotopegeochronological estimates suggest that the ore deposits were formed late in the orogenic history or even after orogeny had demonstrably ended 3,4,10,11. Lung health institute what are copd gold guidelines. The socalled mesothermal gold deposits are associated with regionally metamorphosed terranes of all ages. Orogenic gold deposits mainly form in metamorphic rocks in the mid to shallow crust 515 km depth, at or above the brittleductile transition, in compressional settings that facilitate transfer of hot gold bearing fluids from deeper levels goldfarb et al. Neoarchaean lode gold deposits are commonly interpreted to have formed during a single late tectonic gold mineralization event. Input data for the present study are existing gold deposits, mapped and interpreted faults, and multiscale.
Lode gold deposits of the western and eastern provinces, south island, new zealand, formed as a part of the. On the source of orogenic gold geology geoscienceworld. Gold deposits can still be seen today forming in some active geothermal areas. Meerdere documenten samenvoegen in een pdf bestand. Within the host volcanosedimentary sequences at the province scale, worldclass orogenic gold deposits are most commonly located in.
Orogenic gold deposits, or gold deposits in metamorphic rocks, are the spatially and temporally most widespread gold deposit type, defining important exploration targets in precambrian shields and in phanerozoic orogen ic belts. Orogenic gold deposits are gold lodes within and associated with metamorphic belts 1,7,8,9. Maakt het mogelijk om pdfbestanden samen te voegen met een simpele drag anddrop interface. The massive deposits of the witwatersrand mines in south africa have produced more than 40 percent of the worlds total production of gold. Comments on genesis although still regarded as controversial, intrusion related gold deposits irgd. Gold can be deposited in several locations, all the way from its source, or mother rock, right the way down to the sea. The gold deposits of california are classified as orogenic gold deposits and placer deposits. April 17, 2014, the company changed its name to golden predator mining corp following a merger with redtail metals corp.
Orogenic gold deposits in northwestern bc have formed at different depths in secondthirdorder structures along the longlived jurassic to eocene, crustalscale llewellyn fault zone in the late cretaceous 75120 ma. Orogenic gold deposits of china society of economic. A systematic framework for targeting highgrade ore. To register visit au the course will be held at curtin universitys wmc conference centre. Caroline laplante, exploration country manager, suriname samuelle gariepy, senior exploration geologist, rosebel gold mines. One of the worlds biggest gold deposits is finally making. Orogenic gold deposits are epigenetic mineral deposits groves et al. Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. Classification of mineral deposits geology for investors. Mesothermal and greenstone gold deposits aka orogenic geology formation. Nov 27, 2012 further west in victoria there is very little gold in granite eg a bit around mafeking in the grampians, and north of lancefield, and only mafeking had any significant production from deposits in granites different in the northeast of the state, eg glen wills was important. Mesothermal gold deposits form half way up through the rise of the melt from the deep crust to the surface usually at a depth of less than 10 km but greater than 1 km.
Dr richard goldfarb is a world expert on orogenic gold deposits. The main factor causing gold to become deposited in the locations where it does is its superior weight over the majority of other materials which end up in a. Ores were formed during compressional to transpressional deformation processes at convergent plate margins in accretionary and. Mineralizing systems are defined to include all geologic factors that control the generation and preservation of mineral deposits and emphasize the processes responsible for deposit formation at a variety of scales. Just starting out with the hobby of amateur gold prospecting and want to know where to find gold deposits. The term mesothermal veins is really a sack term, referring simply to the depth formation. Alamos and aurico metals announce completion of merger. Our pdf merger allows you to quickly combine multiple pdf files into one single pdf document, in just a few clicks. Before you get out into the field to try your hand at gold panning or metal detecting, its worth taking a moment to learn about the different types of gold deposits. Full details of the course are presented in the brochure available here. A peculiar feature of these deposits is the association of gold with a variety of copper sulfides and the rare copper arsenides domeykite and koutekite which is atypical for orogenic type gold deposits.
Pdf evidence of upgrading of gold tenor in an orogenic quartz. These deposits are associated with deepsourced fluids channelled along crustalscale shear zones hosted within quartzfilled fault and fracture meshes that formed in association with brittleductile shear zones. Eluvial gold placers boyle, 1979, aubearing saprolite becker, 1895. How the various types of mineral deposits form within the earths crust. Soda pdf is the solution for users looking to merge multiple files into a single pdf document. Highgrade gold ore from the harvard mine, jamestown, california, a wide quartz gold vein in californias mother lode. Although empirical correlations between structural heterogeneities and ore shoots have long been noted and certain key physical processes elucidated, no integrated, systembased. From an exploration point of view, especially for large gold companies, efforts have to be focused on models that have the best chance of yielding large deposits. Oreforming processes of the daqiao epizonal orogenic gold. Other articles where endogenic phenomenon is discussed.
Orogenic gold, or gold deposits in metamorphic rocks, and associated placer deposits, comprise about 6575 percent of this endowment, with lodes existing as structurallyhosted vein and or disseminated orebodies. Fluid origin and structural enhancement during mineralization. Gold deposits in the pine creek inlier likely formed moreorless simultaneously with emplacement of the posttectonic cullen batholith at 18351820 ma. Nov 10, 20 dr richard goldfarb is a world expert on orogenic gold deposits. Mesothermal and greenstone gold deposits aka orogenic. The descending meteoric waters oxidize the primary hypogene sulfide. Gold occurs in a wide range of deposit types and settings, but this paper is concerned with deposits in which gold forms the main economic commodity or a coproduct. Archean orogenic lode gold in the superior province of. Groves1 1centre for global metallogeny, university of western australia, 35 stirling highway, crawley, wa 6009, australia. Prospectivity analysis of orogenic gold deposits in saqezsardasht goldfield, zagros orogen, iran by a. Epithermal gold deposits part ii geology and gold deposits of the oatman district, northwestern arizona by ed dewitt, jon p. The application of deposit scale structural targeting to orogenic gold deposits is primarily concerned with locating volumes of highergrade mineralisation ore shoots within a broader, host structural system. Orogenic gold mineral systems of the north american. Orogenic gold deposits have formed over more than 3 billion years of earths history, episodically during the middle archean to younger precambrian, and continuously throughout the phanerozoic.
There are six worldclass settings for magmatichydrothermal gold deposits. Some gold bearing areas, including national parks, are closed to prospecting. The details will be debated until the sun cools, but the broadbrush classification of mineral deposits is generally understood. Introduction to orogenic gold deposits investing news network november 23rd, 2014 orogenic deposits are the source of much of the worlds gold. Pacton gold is a canadian exploration company with key strategic partners focused on the exploration and development of high grade conglomerate and orogenic gold properties located in the districtscale pilbara gold rush in western australia and the red lake district, ontario. Blevin date unknown has documented eastern australian irgs deposits for eastern australia. It is acknowledged that magmatic or thermally driven.
This class of gold deposit is characteristically associated with deformed and metamorphosed midcrustal. Jul 29, 20 geologists, are known to have more opinions than economists, so it should come as no surprise that the classification of mineral deposits, is an ongoing hot topic. The kalgoorlie and kambalda gold camps are located to the north and south of new celebration deposits, along the strike of the blfz. The development of thought and the history of investigations on ores in metamorphic terranes aretraced.
Timing, nature and characteristics of orogenic gold. Orogenictype coppergoldarsenicbismuth mineralization. While not all favourable structural sites will host mineralisation, it is argued that without the in. These stages are part of the global initiative for chronic obstructive lung disease gold system. Algoma type bifhosted gold deposits 4 moz au meadowbank. This online pdf merger allows you to quickly combine multiple pdf files into one. Scheelite from 25 representative orogenic gold deposits from various geological settings was investigated by epma electron probe microanalyzer and laicpms laser ablationinductively coupled plasmamass spectrometer to establish discriminant geochemical features to constrain indicator mineral surveys for gold exploration. Completion of the merger also marks the inception of a new company, aurico metals. Orogenic gold deposits represent by far the most economically important primary gold mineralisation in victoria, accounting for almost all primary gold production more than 1100 tonnes and include most of the known and potential resources. Numerous and diverse gold deposit types formed during the cenozoic era include epithermal, porphyry. Alluvial gold refers to gold found in riverbeds, streambeds, and floodplains. The bestknown of the exogenetic ores is alluvial gold. In ore deposit geology, supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Archean orogenic lode gold deposits are the result of large, complex mineralizing systems that have developed within many archean terrains.
He explains how orogenic gold formed during plate tectonic collisions and especially during continental growth. Mesothermal and greenstone gold deposits aka orogenic geology. Gold can be described according to its natural size and nature of occurrence. Orogenic gold deposits or intrusionrelated gold systems. Parameters for the formation of orogenic gold deposits. Orogenic gold, or gold deposits in metamorphic rocks, and associated placer deposits, comprise about 6575 percent of this endowment, with lodes existing as. Table 2 shows the distribution of gold deposits among the types listed in table 1 from a population of 103 deposits.
Deze gratis online tool maakt het mogelijk om meerdere pdf bestanden of afbeeldingen te combineren in een pdf document. Diversity of gold deposits, geodynamics and conditions of. Detailed material for this globally important deposit type will be provided on tectonic and structural controls. We invite contributions on all aspects of geochemistry applied to these intriguing deposits. The saramacca gold deposit, a new orogenic gold discovery in the guiana shield amec round up 2018, vancouver l tsx.
Trace element composition of scheelite in orogenic gold. Models and exploration methods for major gold deposit types. Apr 24, 2014 copd gold guidelines there are four stages categorized under the copd gold guidelines. Orogenic gold deposits are a widespread coherent group of epigenetic mineral deposits controlled by a similar set of factors groves, 1993, knoxrobinson, 2000 and are sited in accretionary or collisional orogens of all ages. Most quartz veins in the shear zone, with and without gold mineralization, were boudinaged during progressive shear deformation with.
The origin of these ancient oresseveral billion years oldis controversial. Since the first production in 1878, almost 28 million troy ounces of gold have been extracted, worth 987 million dollars at present price causing the mine to be the most valuable in the united states. If most of your files have form fields, you may want to consider merging or. The company is a reporting issuer in british columbia, alberta, ontario and. Violations may accrue major fines and in more serious cases, possible jail time. Geographically, the kalgoorlie deposits are located at latitude 30. Deposits can range from single small quartz veins to large and commonly highgrade, faultshear controlled systems containing in excess of 25 million ounces of gold. The ore deposits fall in a general category of lode orogenic gold deposits. Phillips and powell 2011 either as the erosion of primary gold deposits or from hydrothermal. The terms metamorphosed, metamorphic, and metamorphogenic as applied to ores are also considered. Au disseminated in laterite and saprolite that developed under conditions of tropical weathering fig.
Farhang aliyari, ebrahim rastad and mohammad mohajjel department of geology, tarbiat modares university, tehran, iran abstract most of the known large gold deposits in iran are located along the sanandajsirjan zone, western iran, which. Homestake mine, located in western south dakota, was created in 1876. If a gold bearing area is on privatelyowned land, be sure to obtain permission from the owner in writing prior to prospecting. Many of the midcretaceous orogenic gold deposits developed in and adjacent to these midcretaceous fault zones. Pdf merge combine pdf files free tool to merge pdf online. This deposit is a classic example of a lowsulfide turbidityhosted orogenic gold quartz deposit sulfide less than 25% located in the folds of sandstoneshale rock as a saddle reef and as discordant veins and stockwork, predominantly in the anticlinal domes. Recent results on structural controls, relative timing and orogenic context of mineralization archean orogenic lode gold in the superior province of manitoba.
The saramacca gold deposit, a new orogenic gold discovery. Victoria hosts one of the worlds largest orogenic gold provinces. Alteration at all mines is distinctly present, variable in intensity and alteration products. Geochemistry, alteration, and genesis of gold mineralization in the okote area. Orogenic gold deposits are among the worlds largest and richest such as the california mother. A proposed classification in the context of their crustal distribution and relationship to other gold deposit types, authordavid i. The resulting goldbearing quartz veins are emplaced over a unique depth range for hydrothermal ore deposits, with gold deposition from 1520 km to the near surface environment. It is invariably elemental gold and usually made up of very fine particles.
So in putting these two words together, we have placer geology as the nature and features of the formation of deposits of gold and other valuable minerals within a streambed. Jun 20, 2010 the jinshan orogenic gold deposit is a worldclass deposit hosted by a ductile shear zone caused by a transpressional terrane collision during neoproterozoic time. Examples of such deposits are numerous and include the tomingleycaloma sytem in nsw, the gympie deposit in queensland, and the slatebelt deposits of victoria e. Idealized cross section of lateritesaprolite au deposit. The characteristics, origins, and geodynamic settings of. As the price of gold increased dramatically in the late 1970s, so did interest in the understanding of these gold deposits. Orogenic gold deposits bohlke, 1982 dominantly form in metamorphic rocks in the mid to shallow crust 515 km depth, at or above the brittleductile transition, in compressional settings that facilitate transfer of hot goldbearing fluids from deeper levels goldfarb et al. There are orogenic gold deposits the more typical quartz gold veins such as. Distribution of orogenic gold deposits in relation to fault.
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