Most of the worlds copper comes from porphyry ore deposits. Porphyry copper deposits of the american cordillera. It refers to large, relatively low grade, epigenetic, intrusionrelated deposits that can be mined using mass mining techniques. The paleoproterozoic coppergold deposits of the gaoua. Generation of porphyry copper deposits by gasbrine reaction. Srednogorie zone is a part of the carpathianbalkan metallogenic province and it is characterized by upper cretaceous magmatism and disposition of numerous copper, gold copper, copper molybdenum and copper base metal deposits. Although at that time porphyry copper deposits were well. Stochastic rock type modeling in a porphyry copper deposit. However, a wellknown, but unresolved paradox, is that arc magmas traversing thick crust, particularly in continental arcs, are generally depleted in cu whereas in. Porphyry mineral deposits are formed when two plate tectonic plates collide in an advanced subduction zone, then cools off reacting with existing rocks and finally forming a copper deposit. Porphyry deposits are the worlds principal resources of cu, mo, and re, and are major resources of au and ag. Lesage, mineral deposit research unit, the university of british columbia, vancouver, bc. The original definition was based on the aumo ratios of porphyry copper deposits with no reference to their copper content, and resulted in the suggestion that goldrich deposits were found largely in island arc regions kesler, 1973. Porphyry copper deposit exploration and resource assessment objectives and guides.
Host rocks for the ore are cretaceous andesitic flows and sedimentary rocks overlain unconformably by lower tertiary volcanics. This study focuses on the features at resolution that formed from acidic hydrothermal fluids including sericitic and advanced. A plate tectonic model for the origin of porphyry copper deposits. Geochronology of the porphyry copper deposits and related. The composition of rhomb porphyry places it in the trachytelatite classification of the qapf diagram. Classic provinces in continental settings include the northern. Porphyry ore deposits are the source of much of the copper, molybdenum, gold and silver used by humans. Pdf the formation of porphyry copper deposits researchgate. Laboratory experiments suggest that these deposits form in a twostage process over thousands of years, from the interaction between.
Much of the worlds economic copper resources are hosted in porphyry copper deposits pcds, shallow level magmatic intrusions associated mostly with thick 45 km magmatic arcs, such as mature island arcs and continental arcs. How to make porphyry copper deposits sciencedirect. Porphyry copper, gold, and molybdenum deposits society of. Sillitoe 27 west hill park, highgate village, london n6 6nd, england abstract porphyry cu systems host some of the most widely distributed mineralization types at convergent plate boundaries, including porphyry deposits centered on intrusions. The level of displacement is usually shallow at less than two kilometers below surface in an active volcanic area. The assarel porphyry copper ore deposit is situated in the central part of srednogorie zone near panagurishte town. Primary commodities copper is the primary commodity of economic interest in most porphyry copper deposits, although some deposits with low.
Porphyry and vein copper gold deposits in the ordovician macquarie volcanic province, lachlan orogen. Mar 29, 2018 porphyry copper deposit modelscientific investigations report 20105070b u. Industrial grinding estimation of blended ore from porphyry. Stochastic modelling of deep magmatic controls on porphyry. The radiometric survey its important to discover the alteration k u. Porphyry copper deposits are copper orebodies that are formed from hydrothermal fluids that. Introduction copper has been mined in japan since the ninth century. This report contains a revised descriptive model of porphyry copper deposits pcds, the worlds largest source about 60 percent and resource about 65 percent of copper and a major source of. Pakistan geological survey mineral information series 9, 21 p. The gaoua copper deposit, one of very few precambrian porphyry copper deposits known in west africa, formed in a volcanicarc setting that predated the eburnean orogeny in the boromogoren greenstone belt. Significant porphyry copper gold targets confirmed at the commonwealth project near the boda discovery in new south wales follow up work to commence in may new rock chip assay data demonstrates that many of the crucial fundamental geochemical components required to form a large porphyry copper gold deposit are.
The vast array of ore deposit types and their particular. Gold endowments of porphyry deposits controlled by. When it comes to porphyry deposits there are a number of variations on a theme and the deposits can be copper only, they can be copper gold, copper molybdenum or molybdenum only but regardless of the metal mix the process of deposit formation is the same. Stochastic rock type modeling in a porphyry copper deposit and its application to copper grade evaluation hassan talebia. Owing to the complexity, a succinct definition that includes the essential attributes of this deposit class is elusive. Geological survey global mineral resource assessment.
The geological characteristics, geochemical signature and. The resolution deposit is a giant, deep, highgrade deposit in the laramide porphyry copper province of arizona that is currently being developed. Porphyry copper deposits are low grade, but are important sources of copper because they can be worked at a large scale for low costs. Porphyry deposits are the worlds principal resources of cu, mo, and re, and are major. Among the first recognized as having porphyry copper potential by midcentury were the disseminated ores at silver bell. Pdf this report contains a revised descriptive model of porphyry copper deposits pcds, the worlds largest source about 60 percent and. Originally, the term porphyry copper was applied to stockwork copper mineralization in felsic, porphyritic igneous intrusions. Rhomb porphyry is a volcanic rock with graywhite large porphyritic rhombusshaped phenocrysts embedded in a very finegrained redbrown matrix. The mvb, within the eastern lachlan orogen, is considered highly prospective for large scale porphyry gold copper deposits, as demonstrated by the presence of the world class cadia valley porphyry district located 110km to the south 49moz au.
Porphyry ore typically forms in magmatic arcs above subduction zones. This report contains a revised descriptive model of porphyry copper deposits pcds, the worlds largest source about 60 percent and resource about 65 percent of copper and a major source of molybdenum, gold and silver. Copper is a moderately incompatible chalcophile element. The proposed contamination model is another way to form porphyry copper deposits. Gold abundances in porphyry copper deposits vary greatly, complicating efforts to define goldrich porphyry copper deposits. The systems commonly define linear belts, some many. A gold and magnetiterich variant of arizona porphyry copper systems. Porphyry cu systems host some of the most widely distributed mineralization types at convergent plate boundaries, including porphyry deposits centered on intrusions. Porphyry copper deposits commonly contain hundreds of millions of metric tons of. Types of copper deposits in the world an investors. Most porphyry copper cu deposits are distributed along convergent margins fig. The term porphyry is also used for a mineral deposit called a copper porphyry. The problem is that while most of the magmas at convergent margins are highly oxidized, porphyry cu deposits. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601.
Countryrock contamination of magmas associated with the baogutu porphyry cu deposit, xinjiang, china. Ore mineralization forms an ore body, presented by large stock work and it has ellipsoidal contours. The ore mineralization is forms mainly fine veinlets in craks and mineral disseminations. Copper porphyry is a form of copper deposit that is often characterized as lowgrade, typically with 0. Porphyry deposits, our main source of copper and of significant amounts of mo, re and au, form at convergent margins in association with intermediatefelsic magmas. Although copper has been mined from a number of different types of mineral deposits, porphyry copper deposits are the most important source for copper, accounting for more than 60 percent of the annual world copper production and approximately 65 percent of the known total copper resource. Porphyry copper deposits result from the complex interactions and feedbacks of many processes. Associated with late cretaceous subvolcanic bodies and porphyry dikes intruded into cambrian metamorphic rocks and carboniferous granodiorites. This deposit type also contains a great abundance of gold and silver. Skarns are formed when hot magma intrudes the limestone the fluids from the intrusive alter the limestone to form an exoskarn. This report contains a revised descriptive model of porphyry copper deposits pcds, the worlds largest source about 60 percent and resource about 65 percent of copper. What the best geophysical survey method for exploring and discovering a porphyry copper deposit. Largescale sodiccalcic alteration around porphyry copper.
Economic filters for evaluating porphyry copper deposit resource assessments using gradetonnage deposit models, with examples from the u. The different stages of cooling that create porphyritic textures in intrusive and hypabyssal porphyritic rocks also lead to a separation of dissolved metals into distinct zones. A total of 276 samples was collected from 203 localities over an area of 5 km2 at elevations between 2,900 and 3,300 m. Eightyfive percent of the deposits were emplaced during the eastward transgression of the cordilleran volcanic arc in middle cretaceous through eocene time. Porphyry copper deposit model free download pdf ebook. The term porphyry copper is derived from the texture of the igneous rock that forms these intrusive bodies. Most porphyry copper cu deposits are distributed along.
Pdf copper is a moderately incompatible chalcophile element. The miocene wafigolpu goldrich porphyry cuau deposit, and associated epithermal au mineralisation is located in the morobe province of png, and has a currently published resource of 28. The alteration assemblages can be separated into two groups, broadly corresponding to the stages previously identified from underground studies, al. Epithermal gold for explorationists paper 200201, april 2002 5 mineralogical differences used to categorise the styles of low sulphidation epithermal gold deposit styles corbett and leach, 1998. Largescale sodiccalcic alteration around porphyry copper systems. The formation of porphyry copper deposits institute of geochemistry. Sericitic and advanced argillic mineral assemblages and.
Geological survey of new south wales, report gs 20190306, digs. The importance of porphyry deposits as a copper and gold resource gold resources. Potassic alteration zones and aveinlets are strongly developed at cerro casale, whereas they are. Therefore, porphyry cu deposits are usually oxidized with oxygen fugacities dfmq. Porphyry deposits are the worlds leading source of copper and molybdenum. Porphyry copper deposit, large body of rock, typically a porphyry of granitic to dioritic composition, that has been fractured on a fine scale and through which chalcopyrite and other copper minerals are disseminated. Department of mining geology, royal school of mines, imperial college of science and. Further extensive porphyry goldcopper mineralisation at.
Ray mine, arizona, one of the largest porphyry copper deposits in the united states. As thus, aster data have been widely used for geologicalstructural mapping and ore minerals exploration, particularly for porphyry copper. Porphyry deposits represent an important resource of copper. Consequently, this descriptive model uses a working definition of a porphyry copper deposit. Countryrock contamination of magmas associated with the. Chemical and isotopic data cited are consistent with the generation of the com ponents of calcalkaline igneous rocks and porphyry ore deposits by partial melting. The occurrence of the porphyry copper deposits of mexico appears to be independent of the terrane intruded and the copper content of the wall rocks where the wall rocks predate the volcanic. Economic filters for evaluating porphyry copper deposit. The term porphyry copper now includes engineering as well as geological considerations. Examples from the highland valley copper district, guichon batholith, southcentral british columbia k. Porphyry copper deposits are very large mineralized systems that are typically formed by relatively small intrusions stocks, which are several thousand.
Briggs over the last several years, many of you have probably heard the term porphyry copper and wondered what everyone is talking about. Collectively, these type of deposits are known as porphyry copper deposits. Tokyo, society of resource geology, resource geology special issue 19, p. However, a wellknown, but unresolved paradox, is that arc magmas traversing thick crust, particularly in. Copper resources a geological cross section through the batu hijau porphyry deposit, indonesia 920 million tons of ore grading 0. The kahang cumo porphyry deposit is located in the middle part of the urumieh. Mar 15, 2017 porphyry deposits, our main source of copper and of significant amounts of mo, re and au, form at convergent margins in association with intermediatefelsic magmas. Hypogene alteration and mineralization in the dos pobres porphyry cuaumo deposit, safford district, arizona. Because some porphyry mo deposits contain significant w, the few papers that document mow and w porphyry deposits are also provided in this subsection. Pdf estimating numbers of undiscovered mineral deposits has been a source of unease among economic geologists yet is a fundamental. Alteration includes propylitic, dominated by chlorite and epidote with silicification and pyritization. Porphyry porphyry an igneous rock of any composition that contains conspicuous phenocrysts in a finegrained groundmass.
Among the first recognized as having porphyry copper potential by midcentury were the disseminated ores at silver bell, described by richard and courtright 1954. The speciation of sulfur is controlled by oxygen fugacity. In general, porphyry deposits are characterized by low grades of ore mineralization, a porphyritic intrusive complex that is surrounded by a vein stockwork. Barton eric seedorff center for mineral resources, department of geosciences, university of arizona, tucson, arizona 857210077. A porphyry deposit is a semiclosed system that usually. Why no porphyry copper deposits in japan and south korea. Pdf the sarcheshmeh porphyry copper deposit, kerman.
Breccias associated with porphyry copper deposits have been a source of fascination for many researchers. Copper porphyry deposits are almost always mined in industrialscale open pit operations. Data metallogenicacentered information system covering the worlds ore deposits. The studied porphyry copper deposit is located mainly in the volcanics and intrusive, granitoids rocks. Porphyry copper gold deposits are large volume, lowgrade disseminations formed by precipitation of copper and gold plus molybdenum from fluids of magmatic origin 1. Stochastic modelling of deep magmatic controls on porphyry copper.
A mineralogical analysis of the igneous rocks and alteration zones including halogen element systematics related to cu mineralization processes. The alteration and mineralization in porphyry cu systems, occupying many cubic kilometers of rock, are zoned outward from the stocks or dike swarms, which typically comprise several generations of intermediate. Therefore, porphyry cu deposits are usually oxidized with oxygen fugacities. The formation of porphyry copper deposits springerlink. Jan 11, 2014 the middle of an idealized porphyry copper system. Porphyry cu deposits in china contain a total resource of 47 million tonnes mt cu at average grades ranging mostly from 0. After doing an extensive literature survey at the best university library i find these exploration methods. Porphyritic texture is characterized by larger crystals of feldspar and quartz, known as phenocrysts, which are surrounded by a matrix of very finegrained crystals. Porphyry copper deposit model, chapter b of mineral deposit. Pdf the sarcheshmeh porphyry copper deposit, kerman, iran. It refers to large, relatively low grade, epigenetic, intrusionrelated deposits. The major products from porphyry copper deposits are copper and molybdenum or copper and gold. Goldrich porphyry deposits occur in both continental and islandarc orogenic settings.
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