Sillitoe and others published supergene oxidized and enriched porphyry copper and related deposits find, read and cite. T1 controls on supergene enrichment of porphyry copper deposits in the central andes. The central andes host some of the worlds largest porphyry copper deposits. The economic viability of these deposits is dependent on the size and quality of their supergene enrichment blanket.
Copper enrichment occurs when pyrite is oxidized by. Harraz presentation supergene enrichment 2 outline of topic 9. Copper oxides are defined as those copper minerals containing oxidized anions, especially copper oxides, sensu strictu, sulfates, phosphates, carbonates, and. Tyrone is one of few deposits in the laramide porphyry copper province with clear evidence for both eocene and miocene supergene enrichment events that have been dated by 40ar39ar. Twentyfive samples of supergene alunite collected from deeply developed supergene profiles in porphyry copper deposits and prospects between latitudes 20. Supergene sulfide enrichment, also called secondary enrichment, in geology, natural upgrading of buried sulfide deposits by the secondary or subsequent deposition of metals that are dissolved as sulfates in waters percolating through the oxidized mineral zone near the surface. Tectonic controls, timing and geochemistry of supergene enrichment of the tyrone porphyry copper deposit, grant county, new mexico a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy in geology by craig j. Supergene oxidized and enriched porphyry copper and. The descending meteoric waters oxidize the primary sulfide ore minerals and redistribute the metallic ore elements. Boyongan is a blind copper gold porphyry deposit that was discovered by anglo american exploration philippines, inc. Therefore supergene oxidation and enrichment processes were active from the early oligocene to the middle miocene, a minimum of 20 m. The ore thus enriched forms the secondary, or supergene sulfide, zone and overlies the primary, or hypogene, zone. Mineralization in the district consists of at least three distinct disseminated porphyry copper deposits and several skarn replacement deposits. Ore enrichment kghm corporate website20200402 a mechanical process of copper ore enrichment is essential for effective smelting.
Supergene enrichment of copper deposits since the mafiadoc. Much of the early his tory of these deposits has been recorded from economic and engi. Mathematically this formulation represents the supergene weathering process as a moving boundary problem. Supergene enrichment required significant rainfall. Supergene mineralisation of the boyongan porphyry coppergold. Enrichment processes in oxidizing sulfide mine tailings. The paleoclimatic signatures of supergene metal deposits. The enrichment blanket at the chuquicamata deposit in chile is reported to attain a thicknesses of up to 2,500 feet. Supergene enrichment occurs at the base of the oxidized portion of an ore deposit. Porphyry copper deposit exploration and resource assessment objectives and guides. Eocene porphyry cu deposits that contains supergene mineralization and provides. First upb laicpms in situ dating of supergene copper. The north silver bell deposit is located at the north end of the district and. Several distinct events of leaching and enrichment were responsible for supergene copper mineralization found in the deposit.
Definition weathering processes and supergene ore deposits conditions that influence supergene enrichment ideal starting material zones. A first principles approach to supergene enrichment of a. Introduction the monywa copper district is 115 km west. The fundamental chemical principles of supergene processes were elucidated during the early decades of the twentieth century, mainly from studies in the western united states. The reactions for the same mineral are written for different possible redox couples. The mean values and 1sigma variations for supergene enrichment chalcocite are, for sedimentary copper chalcocite are, and for hypogene chalcocite is. N2 the central andes host some of the worlds largest porphyry copper deposits. Copper was mostly removed from the sericitic capping, but iron, molybdenum, and gold were relatively immobile during supergene leaching. Munchmeyer c 1996 exotic deposits products of lateral migration of supergene solutions from porphyry copper deposits.
Geophysical case history of north silver bell, arizona. The ore mineralogy of the supergene blanket is dominated by chalcocite digenite covellite rimming pyrite. Two distinct massive chalcocitel enrichment zones have been distinguished in the jurassic to eocene magmatogene copper deposits of the copiap6 region, which include veins, breccia pipes, stockworks, porphyry copper deposits, and stratabound mantos sulfide enrichment occurred in the interval between the lower eocene and the upper. The evolution of supergene enrichment in the morenci by. Exotic copper deposits, ferricretes, and manganocretes associated with porphyry copper deposits in arizona, new mexico, timothy s.
Supergene and exotic cu mineralization occur during periods of. Hydrothermal alteration of the rocks of the morenci porphyry copper deposit is well described in lindgren 1905a, reber 1916, bennett 1974, preece, stegen and weiskopf 1993, and walker 1995. Controls on supergene enrichment of porphyry copper deposits in the central andes. Current inferred mineral resources for boyongan are estimated at 219 million tonnes of combined oxide and sulfide material with an average grade of 0. Sillitoe and others published supergene oxidized and enriched porphyry copper and related deposits find, read and cite all the research you need on researchgate. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. Use of cu isotopes to distinguish primary and secondary cu. The booubyjan deposit has undergone a substantial increase of copper grades near surface through supergene enrichment processes. Supergene mineralisation of the boyongan porphyry copper gold deposit, surigao del norte, philippines by allan maglaya ignacio b. Pdf supergene enrichment of copper deposits since the onset of.
Supergene enrichment of copper deposits since the onset of. The economically important results of supergene oxidation and enrichment in porphyry cu systems have been addressed elsewhere sillitoe, 2005, and references. Morphology of zoning gossans and cappings oxidation and solution in. Published models that have strongly influenced exploration policy suggest that supergene enrichment ceased at 14 ma due to an increase in aridity. Among the first recognized as having porphyry copper potential by midcentury were the disseminated ores at silver bell, described by richard and courtright 1954. Hydrothermal alteration of the rocks of the morenci porphyry copper deposit is well described in lindgren 1905a, reber 1916, bennett 1974, preece, stegen and. Supergene enrichment processes in porphyry systems. Cook s s and porter t m, 2005 the geologic history of oxidation and supergene enrichment in the porphyry copper deposits of southwestern north america, in porter t m, ed, super porphyry copper and gold deposits. Porphyry copper deposits of the american cordillera. The early oligocene supergene activity affected deposits in the paleocene porphyry copper belt, whereas early and middle miocene supergene processes are documented in the early cretaceous, paleocene, and late eocene to early oligocene porphyry copper belts.
A unified description of supergene enrichment of a porphyry copper protore is. All forms shown may be important at different depths and times during supergene enrichment of a porphyry copper deposit. Chile introduction in the cu deposits of the atacama desert, northern chile, the meteoric supergene enrichment stage covered a long period extending from 44 ma and ending near 149ma with a stepwise onset towards the hyperaridity in the. Descriptions of the tertiary volcanic and sedimentary. Total production for that period is reported at 75. Supergene processes are all but inactive under the hyperarid climatic conditions now prevailing in the chilean norte chico below ca. Prominent examples are several chilean copper porphyry deposits that have important exotic oxide schematic profile of a deeply weathered copper sulphide ore deposit, displaying the supergene secondary zonation resulting from redistribution of elements. Supergene enrichment of copper deposits since the onset of modern hyperaridity in the atacama desert, chile article pdf available in mineralium deposita 445. Twentyfive samples of supergene alunite collected from deeply developed supergene profiles in porphyry copper deposits and prospects between latitudes 20 and 27 s in northern chile yield kar ages ranging from about 34 to 14 ma. This investigation of leached caps in meiduk and parkam porphyry copper deposits pcd in kerman cenozoic magmatic arc kcma of sw iran indicated that the fertility of supergene enrichment zones may be inferred from the mineralogical and geochemical characteristics of their associated leached caps. Systems deposits commoditiescritical minerals table for the earth mapping resources initiative. The importance of porphyry deposits as a copper and gold resource gold resources.
Read more about geological summary and perspective of porphyry copper deposits in southwestern north america, in pierce, f. Pdf controls on supergene enrichment of porphyry copper. Atacamite in the oxide zone of copper deposits in northern. Supergene copper deposits supergene enrichment is essential for the economic viability of many porphyry copper deposits reich and vasconcelos 2015 this issue, and determining when and how supergene enrichment has occurred is important when exploring for enriched and exotic copper deposits mote et al.
A first principles approach to supergene enrichment of a porphyry. Supergene mineralisation of the boyongan porphyry copper. Chile introduction supergene enrichment of cu deposits in the atacama desert of northern chile has been a principal factor in this region becoming the greatest producer of cu in the world. Origins of chalcocite defined by copper isotope values. University of nevada, reno tectonic controls, timing and. Controls on supergene enrichment of porphyry copper deposits. Supergene alteration of porphyry copper deposits in the central atacama desert occurred over a long period extending from 44 ma, reaching a maximum at 1421 ma, and ending near 9 ma with the onset of hyperaridity arancibia et al. Porphyry copper deposit model, chapter b of mineral deposit. Geology, national institute of geological sciences university of the philippines thesis submitted in partial fulfilment of the requirements of the. Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. Supergene oxidation and leaching processes have led to significant enrichment of porphyry and stratabound mantotype cu deposits, and the economic viability of these deposits is typically dependent on the size and quality of the supergene enrichment blanket that overlies the hypogene cusulfide zones 5, 6. Supergene oxidized and enriched porphyry copper and related.
Overview of the supergene enrichment of the chuquicamata porphyry copper deposit with the associated exotica deposit, chile. Supergene leaching, oxidation, and chalcocite enrichment in porphyry and related cu deposits take place in the weathering. Ore deposits secondary enrichment deposits original deposit is subeconomic. Pleistocene recycling of copper at a porphyry system. Secondary enrichment processes allow concentration of the ore minerals to economic levels. Geochemical modeling of steady state fluid flow and chemical. Age of supergene oxidation and enrichment in the chilean. A midmiocene pluton is inferred to underlie the monywa deposits, but the possibility of porphyry type mineralization within the district is at best highly speculative. Radiometric agedates of supergene alunite also indicate. Leached caps mineralogy and geochemistry as supergene. The deposits and prospects used as examples throughout the text are located and further characterized in figure 1.
Oxidation supergene enrichment linkedin slideshare. Kuroko black ore, oko yellow ore, keiko silicious ore. Geomorphologic environment and age of supergene enrichment of. The deposits may be named after their rock type, like pegmatite huge crystals. This investigation of leached caps in meiduk and parkam porphyry copper deposits pcd in kerman cenozoic magmatic arc kcma of sw iran indicated that the fertility of supergene enrichment zones may be inferred from the mineralogical and geochemical characteristics of their. Yet it is only the very latest mesozoic and cenozoic porphyry copper deposits that have been subject to supergene oxidation and enrichment sillitoe 2005, in spite of the fact that the older. Definitions definition from evans leaching of valuable elements from the upper parts of mineral deposits and their precipitation at depth to produce higher concentrations definition from guilbert and park supergene enrichment occurs when oxidizing acids dissolve metal ions from the protore and redeposited it in. Supergene sulfide enrichment, in geology, natural upgrading of buried sulfide deposits by the secondary or subsequent deposition of metals that are dissolved as sulfates in waters percolating through the oxidized mineral zone near the surface. A natural enrichment and refinement phenomenon abstract louisa lawrance 147. Partially leached, relict chalcocite is found at topographic levels much higher than the current enrichment level, thus indicating an earlier period of enrichment. The tyrone data indicate that evidence for eocene supergene enrichment in these deposits is probably often destroyed by miocene uplift, leaching, and erosion. A unified description of supergene enrichment of a porphyry copper protore is presented based on the principles of metasomatic zoning. Supergene leaching, oxidation, and chalcocite enrichment in porphyry and related cu deposits take place in the weathering environment to depths of several hundred meters.
Controls on supergene enrichment of porphyry copper. In ore deposit geology, supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Supergene enrichment how natural processes have transformed. Pdf supergene enrichment of copper deposits since the.
These deposits can form when dissolution occurs in oxygenated waters and the water moves to a deoxygenated region. Porphyry associated deposits copper gold stockworks and veins. Geochemical modeling of steady state fluid flow and. 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. Enrichment blankets at many porphyry copper deposits form large laterally extensive zones up to 3040 square miles that typically range from 200 to 1,000 feet in thickness, but thin laterally to 10 to 100 feet. Copper ore grades of the cuajone, quellaveco, and toquepala porphyry cumo deposits, situated at 3,000 to 4,000 m a. Porphyry copper deposits are typically mined by openpit methods. Porphyry copper deposit at red mountain, santa cruz county, arizona photo taken by david briggs, october 2009 enrichment blankets at many porphyry copper deposits form large laterally extensive zones up to 3040 square miles that typically range from 200 to 1,000 feet in thickness, but thin laterally to 10 to 100 feet. Copper resources a geological cross section through the batu hijau porphyry deposit, indonesia 920 million tons of ore grading 0. The upper portions of porphyry copper deposits may be subjected to supergene enrichment. This involves the metals in the upper portion being dissolved and carried down to below the water table, where they precipitate. Initial products of supergene oxidation, copiapo mining. Pdf supergene enrichment of copper deposits since the onset.
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