View test prep 2010 porphyry sillitoe from geology 1 at university of texas. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can. A tool for identification and exploration of porphyry copper deposits. Consequently, this descriptive model uses a working definition of a porphyry copper deposit. Till geochemical and mineralogical case studies and surveys carried out around porphyry deposits in glaciated terrain are described here in two.
The jebel ohier deposita newly discovered porphyry copper. Significant quantities of byproduct molybdenum, silver, gold, and platinum are also produced. 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. Epma results for magnetite samples show collisional deposits have higher average contents of fe and ca.
Usgs bulletin 1857e tooker, edwin wilson, james, l. Size of hydrothermal systems relative to extent of economically mineralized rock the total volume of rock affected by heat andor fluid flow related to porphyry copper systems commonly is much greater than estimated from the areas of ore zones or visibly altered rock and may extend 10 km or farther outward from the center of porphyry copper. This increase began in the early 1960s, and the numbers of publications reached a peak during. Average gold contents are generally gt, although a few deposits are richer fig. Porphyry copper deposits of the american cordillera frances wahl pierce and john g. General setting of porphyry copper and associated deposit types modified from sillitoe and bonham, 1990. Geology and genesis of major copper deposits and districts of the world. Characteristics, continua, and causes marco einaudi. Mar 29, 2018 size of hydrothermal systems relative to extent of economically mineralized rock the total volume of rock affected by heat andor fluid flow related to porphyry copper systems commonly is much greater than estimated from the areas of ore zones or visibly altered rock and may extend 10 km or farther outward from the center of porphyry copper. Sillitoe 27 west hill park, highgate village, london n6 6nd, england abstract porphyry cu systems host. Experimental study of high to intermediate temperature alteration in.
Skarns are formed when hot magma intrudes the limestone the fluids from the intrusive alter the limestone to form an exoskarn. View test prep 2010porphyrysillitoe from geology 1 at university of texas. Porphyry cu systems host some of the most widely distributed mineralization types at convergent plate boundaries. Because some porphyry mo deposits contain significant w, the few papers that document mow and w porphyry deposits are also provided in this subsection. Request pdf porphyry copper systems porphyry cu systems host. The systems commonly define linear belts, some many. Hydrothermal alteration and mineralization at darrehzar are centered on the stock and were broadly synchronous with its. Sillitoe and gappe 1984 have helped us to understand many aspects of porphyry systems, including that the ore deposits can be. Epithermal gold and silver deposits are typically hosted by volcanic rocks. Porphyry copper definition of porphyry copper by merriam. 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. The darrehzar porphyry cumo deposit is located in southwestern iran 70 km southwest of kerman city. Owing to the complexity, a succinct definition that includes the essential attributes of this deposit class is elusive. Generation of porphyry copper deposits by gasbrine.
Cooling of an aqueous fluid initially containing 2 m nacl, 0. The term porphyry copper is derived from the texture of the igneous rock that forms these intrusive bodies. Deposits assigned to this group include a few porphyries in the chilean maricunga belt. Enter your mobile number or email address below and well send you a link to download the free kindle app. Porphyry copper deposits, that is, copper ore associated with hydrothermal fluids rising from a magma chamber, supply 75% of the worlds copper. Alteration zones at the deposit demonstrated zoning which is comparable with lowelguilbert model proposed for quartzmonzonite type porphyry copper deposits. Here lets understand the geology of porphyries and iron oxide copper gold deposits or iocg as they are known. Porphyry deposits are important sources of copper and molybdenum, as well as gold, silver, and tin sinclair, 2007. International exchange lecture june 1994 high sulfidation.
Jan 23, 2019 the present work attempts to characterize magnetite chemistry in some collisional chahfiruzeh and keder. Porphyry and epithermal systemssciencedriven exploration successes richard sillitoe porphyry and epithermal deposits. Porphyry copper definition is a large lowgrade disseminated copper deposit. See sillitoe, 2010, porphyry systems economic geolo gy, t he best overvi ew of porphyry deposits also his 2005 paper in the economic geology 100 th anniversa ry volu me on su pergene. The intrusives also simulates the limestone altering its composition and forming and endo skarns. Some cenozoic porphyry copper deposits are known to have formed during or shortly after continentcontinent, continentisland arc, or island. Generation of porphyry copper deposits by gasbrine reaction. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Breccias associated with porphyry copper deposits have been a source of fascination for many researchers. Porphyry copper deposit model, chapter b of mineral deposit.
Sillitoe ccop project office, undp technical support for regional offshore prospecting in east asia ras81120, 1984 copper ores 89 pages. Porphyry copper depositsthe primary source of the worlds copperare a consequence of the degassing of intrusion complexes in magmatic arcs associated with. Porphyry copper deposits contain up to 100 t of gold and are among the largest reservoirs of gold in the upper crust kerrich et al. Paulen, in past glacial environments second edition, 2018. Predating or associated with those fluids are vertical dikes of porphyritic intrusive rocks from which this deposit type derives its name. Characteristics and controls of the largest porphyry copper. Copper, gold, and molybdenum are among the important minerals extracted from these deposits.
Epma results for magnetite samples show collisional deposits have higher average contents of fe and ca compared to those of precollisional. Friedrich g h,genkin a d, naldrett a j, ridge j d, sillitoe r h, vokes f m eds geology and metallogeny of copper deposits. Gold can be removed from porphyry copper systems by vapors that separate at high. Porphyry copper deposits are copper orebodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. Pdf porphyry copper systems introduction miguel peral. A system of concentric zoning with cu, mo, au, and k in the center and pb, zn, mn, and fe forming the outer. Sillitoe r h 1986 spacetime distribution, crustal setting and cumo ratios of central andean porphyry copper deposits. 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. Sillitoethe tops and bottoms of porphyry copper deposits. Dec 21, 2012 porphyry type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. Numerous other minor occurrences with porphyry or porphyry related characteristics occur throughout the arc. Porphyry copper systems are mainly developed at convergent plate margins, including continental margin and islandarc settings sillitoe, 2010, where the subduction of oceanic crust is related to. Metallic ore deposits related to porphyry systems encompass a wide variety of.
Sillitoe rh 1993 gold rich porphyry copper deposits. A different but closely related group of deposits to porphyry copper deposits are the skarn deposits. Porphyry cu mo au deposits are commonly associated with shallowly emplaced, relatively lowto hightemperature 300700 c hydrothermal systems richards, 2011richards, 20sillitoe, 2010. Characteristics of porphyry aucu systems in the ordovician. Fluid evolution of the magmatic hydrothermal porphyry copper. Porphyry and epithermal systems sciencedriven exploration successes richard sillitoe porphyry and epithermal deposits. Table of contents pdf society of economic geologists. Cenozoic tectonics and porphyry copper systems of the chilean andes. For modeling purposes a simplified porphyry model was constructed based on known geologic information titley, 1982, and pierce and bolm, 1995. Generalized porphyry copper model anatomy and alteration zoning anatomy of calcalkalic porphyry copper and related mineralization alteration zonation patterns in calcalkalic porphyry systems modified from. Application of metal zoning to gold exploration in porphyry copper. The porphyries occur as tertiary quartzmonzonite stocks and dikes, ranging in composition from microdiorite to diorite and granodiorite. May 28, 2014 porphyry copper deposits are generally composed of a pluglike igneous intrusion a large magma body that is emplaced beneath a volcanic system. Porphyry gold systems are not a very common type of gold deposit.
Hydrothermal alteration porphyry copper porphyry copper deposit econ geol potassic alteration. Jul 28, 2014 additional benefits of exploring for large porphyry copper deposits due to the very large scale of the magmatic and hydrothermal systems that drive the formation of porphyry copper mineralisation, a number of other deposit styles also form within the same broad environment as the porphyry systems themselves. Porphyrytype ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. Porphyry and epithermal systems sciencedriven exploration. The next variation in the classification was used in 1995 by bakker. Phyllic, argillic, silicic and propylitic alteration zones were observed at the surface while potassic alteration zone could be observed at depth in drill core samples. Sillitoe r h 1972 a plate tectonic model for the origin of porphyry copper deposits. Porphyry copper deposits result from the complex interactions and feedbacks of many processes. Nov 01, 2010 the purpose of the study was to 1 delineate permissive areas tracts for undiscovered porphyry copper deposits within 1 km of the surface at a scale of 1.
Additional benefits of exploring for large porphyry copper deposits due to the very large scale of the magmatic and hydrothermal systems that drive the formation of porphyry copper mineralisation, a number of other deposit styles also form within the same broad environment as the porphyry systems themselves. Numerical modeling shows that dynamic permeability responses. See sillitoe, 2010, porphyry systems economic geolo gy, t he best overvi ew of porphyry deposits also his 2005 paper in the economic geology 100 th anniversa ry volu me on su pergene al tered. Richard sillitoes observations and interpretations e. Gold abundances in porphyry copper deposits vary greatly, complicating efforts to define goldrich porphyry copper deposits. Cumo zoning in porphyry systems porphyry cumo deposits are commonly zoned with a deeper, higher temperature molybdeniterich zone and a shallower, lower temperature chalcopyriterich zone. In addition a further ten significant cu andor au systems that may be porphyryrelated in the broader sense exist table 1. This paper presents a brief history of the technological evo lution of southwest porphyry copper deposits as bulk lowgrade. Porphyritic texture is characterized by larger crystals of feldspar and quartz, known as phenocrysts, which are surrounded by a matrix of very finegrained crystals. This ignores the fact that sillitoe 1979 had earlier introduced the concept of a porphyry gold deposit style. Magnetite chemistry in the porphyry copper systems of kerman. An idealized porphyry copper system is shown in fig. Fluid evolution of the magmatic hydrothermal porphyry. Triggers for the formation of porphyry ore deposits in magmatic arcs.
Porphyry copper deposit model free download pdf ebook. They are commonly surrounded by deposits and country rock containing gold that is thought to have been derived from them jones, 1992. Porphyry copper systems, which provide most of the worlds copper resource, are commonly associated. Sillitoe rh 1993 gold rich porphyry copper deposits geological model and from geol 562 at university of kansas. Porphyry copper deposits commonly contain hundreds of millions of metric tons of ore that averages a fraction of 1 percent copper by weight. Two porphyry coppertype mineral occurrences were prospected using multielement soil geochemistry with. The present work attempts to characterize magnetite chemistry in some collisional chahfiruzeh and keder. See sillitoe, 2010, porphyry systems economicgeology. See sillitoe, 2010, porphyry systems economicgeology, the best overview of porphyry deposits also his 2005 paper in the economic geology 100 th anniversary volume on supergenealtered porphyry. Advances in geological models and exploration methods for. 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.
Combined with an enlarging base of descriptive models of porphyry copper. These are somewhat the giants of the ore deposits world. Update of the geologic setting and porphyry cumo deposits of. Porphyry copper depositsthe primary source of the worlds copperare a consequence of the degassing of intrusion complexes in magmatic arcs associated with ancient subduction zones 1,2. In addition a further ten significant cu andor au systems that may be porphyry related in the broader sense exist table 1. Porphyry copper molybdenum and copper gold deposits are centred on shallowlevel porphyry intrusions. Porphyry and epithermal systems sciencedriven exploration successes 1 porphyry and epithermal systems sciencedriven exploration successes. Cenozoic tectonics and porphyry copper systems of the chilean. Magnetite chemistry in the porphyry copper systems of.
Hydrothermal alteration and mineralization at darrehzar are centered on the stock and were broadly synchronous with its emplacement. The study of the tectonic setting of porphyry copper deposits is fundamental to understanding their genesis e. 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. Read the jebel ohier deposita newly discovered porphyry coppergold system in the neoproterozoic arabiannubian shield, red sea hills, ne sudan, mineralium deposita on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Generalized models of porphyry copper deposits anatomy. Characteristics and controls of the largest porphyry. The tops and bottoms of porphyry copper deposits sillitoe, richard h on. Numerous other minor occurrences with porphyry or porphyryrelated characteristics occur throughout the arc. Porphyry coppermolybdenum and coppergold deposits are centred on shallowlevel porphyry intrusions. Pdf porphyry copper systems daniela olivares sedan.