The veintype ores are characterized by quartzpyritechalcopyrite veins of 0. 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 this process, which occurs primarily when fluids are driven off the cooling magma, is one of the main reasons for the. Geophysical signatures of coppergold porphyry and epithermal. Till geochemical and mineralogical case studies and surveys carried out around porphyry deposits in glaciated terrain are described here in two sections.
Hosted by acidic to intermediate intrusives such as granite, granodiorite, tonalite, diorite. Porphyry porphyry an igneous rock of any composition that contains conspicuous phenocrysts in a finegrained groundmass. The majority of porphyry copper deposits occur adjacent to subduction zones i. The radiometric survey its important to discover the alteration k u t. Porphyry cu deposits are generally associated with itype granitoids magma derived from upper mantle melt multiple intrusive events are common in areas of porphyry cu minzn, with the host intrusions being the youngest and most. How to make porphyry copper deposits sciencedirect. Skarns in the porphyry coppergold environment ausimm. Major miners look to copper porphyry deposits for largetonnage, lowcost operations. Newly discovered porphyry copper deposits in north sulawesi celebes are located in two principal districts, each with several centers of porphyry copper mineralization. Hydrogen and oxygen isotope ratios in minerals from. The deposits were discovered by reconnaissance stream silt geochemistry, which detected anomalies of the order of 500 to 1,000 ppm cu, against a background of 100 ppm cu.
Rhenium is recovered as a byproduct during roasting of molybdenite concentrates, which in turn are byproducts from porphyry cumo deposits magyar, 2003. The predicted magnetic anomaly over a porphyry copper system 1. Although molybdenite from porphyry cumo deposits can contain up to 0. The most well known among the porphyrytype deposits are the porphyry copper deposits. Mineralization of cu ores tend to occur at the tops of porphyry systems in cupolas. The term porphyry is also used for a mineral deposit called a copper porphyry. Optimum conditions for development of giant porphyry copper deposits.
Download statistics downloads hoschke, tg 2011, geophysical signatures of coppergold porphyry and epithermal gold deposits, and implications for exploration, research master thesis, university of tasmania. Codes the australian research councils centre for excellence in ore deposit research, university of tasmania, private bag 126, hobart, tasmania 7001, australia. Jan 14, 2020 porphyry coppergold deposits are large volume, lowgrade disseminations formed by precipitation of copper and gold plus molybdenum from fluids of magmatic origin 1. Geology and exploration of porphyry copper deposits in north. It refers to large, relatively low grade, epigenetic, intrusionrelated deposits that can be mined using mass mining techniques.
Porphyryrelated skarns are common around thepacific rim. Porphyry ore deposits, occurring in the western americas. Geology and metallogeny of copper deposits springerlink. Thomson resources porphyry copper gold deposit model. Porphyry copper deposit exploration and resource assessment objectives and guides. Porphyry copper district endeavour 26 north, endeavour 22 and endeavour 27 coppergold deposits. Pdf porphyry copper deposits of the american cordillera. Examples include cadia and goonumbla australia ok tedi png and ertsberg and grasberg indonesia. Location of the western pacific deposits discussed in this thesis 1. The problem is that while most of the magmas at convergent margins are highly oxidized, porphyry cu deposits are very rare, suggesting that. Distribution of worlds porphyry copper deposits modified from singer et. The similarities between the isotopic variations in the calculated hydrothermal waters associated with.
The major products from porphyry copper deposits are copper and molybdenum or copper and gold. The need to remove very large amounts of very hard igneous rocks means that porphyry ore deposits werent mined at all until 1905, when powered shovels and rail. A plate tectonic model for the origin of porphyry copper deposits. Development of a copper porphyry porphyry copper deposits are copper orebodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the.
Porphyry cu deposits are generally associated with itype granitoids magma derived from upper mantle melt multiple intrusive events are common in areas of porphyry cu minzn, with the host intrusions being the youngest and most differentiated plutons. The composition of rhomb porphyry places it in the trachytelatite classification of the qapf diagram. This two volume set describes the great porphyry cuaumo deposits and provinces around the. 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. Jan 11, 2014 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 gold deposit model porphyry deposits are the worlds most important source of cu and mo, and are major sources of au, ag, and sn. C c 12 values of hydrothermal vein carbonates in the porphyry copper deposits delta 2. Originally, the term porphyry copper was applied to stockwork copper mineralization in felsic, porphyritic igneous intrusions. The formation of porphyry copper deposits springerlink. If you would like to participate, you can choose to edit this article, or visit the project page for more information. Porphyry ore deposits are the source of much of the copper, molybdenum, gold and silver used by humans.
Of particular interest are the super porphyry copper andor gold deposits, because of their size, grade and ability to support large scale, long life, profitable operations. After doing an extensive literature survey at the best university library i find these exploration methods. Skarns are formed when hot magma intrudes the limestone the fluids from the intrusive alter the limestone to form an exoskarn. The geology, structure and mineralisation of the oyu tolgoi porphyry.
Porphyry copper deposit model, chapter b of mineral deposit. The purpose of the study was to delineate geographic areas as permissive tracts for the occurrence of porphyry copper. Porphyry copper deposit is part of wikiproject geology, an attempt at creating a standardized, informative, comprehensive and easytouse geology resource. This study focuses on the magmatic characteristics of the three main phases of intrusion at the level of the open pit mine. The problem is that while most of the magmas at convergent margins are highly oxidized, porphyry. Critical factors controlling pd and pt potential in. Pdf the formation of porphyry copper deposits researchgate. 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. Porphyrystyle cuaumo deposits are among the most sought after targets for both base and precious metal exploration in the world today. Pdf geochemistry of porphyry deposits researchgate. Porphyry copper systems1 economic geology geoscienceworld. Porphyry copper deposits commonly contain hundreds of millions of metric tons of ore that averages a fraction of 1 percent. Information on porphyry copper deposits from around the world with grade and tonnage models, a general classification based on geologic setting, mineralogy, with data allowing locations of these deposits to be plotted using gis. Porphyry copper deposits pcds represent shallow level intrusions 25 km in the crust.
Here lets understand the geology of porphyries and iron oxide copper gold deposits or iocg as they are known. Predating or associated with those fluids are vertical dikes of porphyritic intrusive rocks from which this deposit type derives its name. Ring of fire around the pacific ocean, which form along continental margins i. The assessment estimated undiscovered porphyry copper deposits within 1 kilometer of the land surface in three depth intervals. Porphyry deposits are the worlds principal resources of cu, mo, and re, and are major. They account for about 50 to 60% of world cu production and more than 95% of world mo production. View porphyrytype copper deposits research papers on academia. Gold endowments of porphyry deposits controlled by. The problem is that while most of the magmas at convergent margins are highly. The grasberg igneous complex which formed at 3 ma is host to one of the largest copper and gold porphyrytype ore deposits discovered on earth. 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.
Although usually treated as separate to the adjacent porphyry coppergold cuau deposit, skarns near porphyry deposits are commonly inextricably part of the larger cuau systems. Porphyry copper assessment of the tethys region of western. Multiple and prolonged porphyry cuau mineralization and. Porphyry copper deposits are copper ore bodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. May 31, 2015 development of a copper porphyry porphyry copper deposits are copper orebodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the. Analysis of tectonic settings of global superlarge porphyry. Analysis of 55 porphyry copper deposits demonstrates a continuum between porphyry copper gold deposits emplaced at a median depth of 1 km, with a median size of 160 million metric tons of copper. Porphyry ore deposits are low grade meaning that the amount of the element that you want in this case, copper isnt very high.
Geology and exploration of porphyry copper deposits in. Porphyry deposits are important sources of copper and molybdenum, as well as gold, silver, and tin sinclair, 2007. Download the text of this report as a 9page pdf file. Hughes the australasian institute of mining and metallurgy, melbourne. Ip survey can used for the sulfide mapping not for porphyry copper. Elevated pd, pt hundreds of ppb and au contents are associated with typical stockwork magnetitebornitechalcopyrite assemblages, at the central parts of certain porphyry deposits. An exploration framework for porphyry to epithermal transitions in the toodoggone mineral district 94e. Copper skarn deposits occur near many porphyry copper host intru sions that intruded carbonatebearing units einaudi and others, 1981, and skarn mineral zoning patterns may be useful in the targeting of a potentially associated porphyry copper deposit meinert and others, 2005.
Possible regimes where cu may be mobilized include hydrothermal circulation at midocean ridge centers, dehydration or melting of the subducting slab, and late stage. A different but closely related group of deposits to porphyry copper deposits are the skarn deposits. Currently, new porphyry copper deposits are formed somewhere in the world beneath active volcanic territory. Porphyry copper deposits of the american cordillera. Economic filters for evaluating porphyry copper deposit. Collectively, these type of deposits are known as porphyry copper deposits.
Geoscience bc report 201908, mdru publication 424, 101 p. The speciation of sulfur is controlled by oxygen fugacity. 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, currently being the dominant source for cu mo au, are formed in arc. View porphyry type copper deposits research papers on academia. The theory of lithosphere plate tectonics, embodying the concepts of seafloor spreading, transform faulting, and underthrusting at continental margins and island arcs, is employed as a basis for an actualistic, though speculative, model for the origin and spacetime distribution of porphyry copper and porphyry molybdenum deposits. What the best geophysical survey method for exploring and discovering a porphyry copper deposit. Batholith volcano coupling in the metallogeny of porphyry copper deposits. Rhomb porphyry is a volcanic rock with graywhite large porphyritic rhombusshaped phenocrysts embedded in a very finegrained redbrown matrix. Porphyry copper deposit model free download pdf ebook.
Tectonic setting and distribution of major porphyry copper deposits in the central asian orogenic belt. Porphyry coppergold deposits are large volume, lowgrade disseminations formed by precipitation of copper and gold plus molybdenum from fluids of magmatic origin 1. The importance of porphyry deposits as a copper and gold resource gold resources. The intrusives also simulates the limestone altering its composition and forming and endo skarns. Part or all of this report is presented in portable document format pdf. Request pdf porphyry copper deposits in china porphyry cu deposits in china contain a total resource of 47 million tonnes mt cu at average grades. Jan 12, 2017 porphyry deposits are copperrich orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from magmatic intrusions that cooled at depth within the earths crust. A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in the tethys region of western and southern asia was carried out as part of a global mineral resource assessment led by the u. Typically, porphyry copper deposits are lowgrade yet being mined on a large scale via openpits resulting in a processing of at least a few 100 million tons averaging mostly below 1% copper. In porphyry cu deposits, for example, cu grades range from 0. This publication contains a computer file of information on porphyry copper deposits from around the world. The term porphyry copper now includes engineering as well as geological considerations. Porphyry copper deposits commonly contain hundreds of millions of metric tons of ore that averages a fraction of 1 percent copper by weight. The consistently defined deposits in this file provide the foundation for grade and tonnage models included here and for mineral deposit density models singer and others, 2005.
As a mining interested learner, the geology of porphyry copper deposits is vital to your education now in the first exploration geology course i discussed how because our current mining technology all the. We take a look at what makes for a copper porphyry takeover target. Pdf distribution of gold in porphyry copper deposits. These are somewhat the giants of the ore deposits world. Copper resources a geological cross section through the batu hijau porphyry deposit, indonesia 920 million tons of ore grading 0.
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. Porphyry ore typically forms in magmatic arcs above subduction zones. Till geochemical and mineralogical case studies and surveys carried out around porphyry deposits in glaciated terrain are described here in two. Tempo of magma degassing and the genesis of porphyry copper. Characteristics of porphyry aucu systems in the ordovician. Porphyry deposits can, however, be very large, so by extracting and processing very large amounts of low grade ore, enough copper can be found for it to be economically worthwhile.
Metallogenic features of miocene porphyry cu and porphyry. With the development of largescale openpit mining methods and froth flotation techniques for efficient beneficiation of lowgrade ores, the. Porphyrytype copper deposits research papers academia. Hydrogen and oxygen isotope ratios in minerals from porphyry. Request pdf porphyry copper deposits in china porphyry cu deposits in china contain a total resource of 47 million tonnes mt cu at average grades ranging mostly from 0. Porphyry copper depositsthe primary source of the worlds copperare a consequence of the degassing of intrusion complexes in magmatic arcs associated with. Therefore, porphyry cu deposits are usually oxidized with oxygen fugacities. Paulen, in past glacial environments second edition, 2018. Copper is a moderately incompatible chalcophile element.
Some porphyry copper deposits are inconsistent with plate subduction with respect to their formation time, and most of them in the world are associated with tensional environment. Porphyry copper deposits often occur in the upper parts of a subduction zone and in a withinplate orogenic belt. The updated cost models were used to perform an economic analysis of undiscovered resources estimated in porphyry copper deposits in six tracts located in north america. Recent research has focused on the application of porphyry indicator minerals pims, to pinpoint the location of porphyry copper deposits hiding under large amounts of glacial till.