Apr 10, 20 these include direct magmatic segregation or crystallization, magmatic hydrothermal replacement and hydrothermal precipitation in the sense of ironoxidecoppergold iocgtype deposits 9,10,11. In this chapter we turn our attention to other magmatic activity which results in important mineral deposits. Discrimination between magmatic and hydrothermal nicu. Postmagmatic seafloor hydrothermal activity is recognized by intense alteration and formation of a greenschist facies mineral assemblage at temperatures of 250400 c. Magmatic ni deposits are the products of sulfide segregation from maficultramafic magmas naldrett, 2010. Ore deposits produced by magmatic segregation, with special reference to the nickel ores of the sudbury district, ontario stuart st. Mineral deposit mineral deposit magmatic cumulates. This work has been identified with a creative commons public domain mark 1. Introduction ore deposits are crustal concentrations of useful elements that can be exploited at a pro. Magmatic sulfide ore deposits elements geoscienceworld.
If you continue browsing the site, you agree to the use of cookies on this website. Anatomy of a porphyry cu mo au deposit and other spatially related deposits. Through the magmatic segregation process, one or more minerals are concentrated locally during the cooling of magma. It will be noticed that the authors ascribe the formation of these magmatic sulphide deposits to causes very different from those generally accepted. Department of the interior doi inspector general white house egov no fear act foia doi inspector. The sudbury model suggests that magmatic sulfide orebodies occur along the base of. Magmatic ore deposits in layered intrusionsdescriptive. Ppt magmatic deposits powerpoint presentation free to. Magmatic base metals deposits chrome nickelcopper platinum group metals pgm magmatic deposits are so named because they are genetically linked with the evolution of magmas emplaced into the crust either continental or oceanic and are spatially found within rock types derived from the crystallization of such magmas.
Some geologists favor the theory of magmatic segregation, that is, that the ironnickelcopper sulfides separated. Deposition mechanisms of magmatic sulphide liquids. Some ore deposits have such an intimate association with igneous rocks that a common heritage can be inferred. Magmatic and structural controls on the development of. Sulphide and silicate liquids are immiscible meaning they do not mix, so droplets of iron, copper, nickel and platinum sulphides that form at high temperatures and are denser than the surrounding silicate liquid magma sink to the base of the intrusion to form a cumulate layer, where they. Sulfidesilicate textures in magmatic nicupge sulfide. An ore deposit formed by magmatic segregation, generally in mafic rocks and layered intrusions, as crystals of metallic oxides or from an immiscible sulfide liquid. The rocks that are formed as a result of magmatic segregation are called magmatic cumulates.
Ripley, editors additional copies of this publication can be obtained from society of economic geologists, inc. Sulfide saturation of a magma is not enough in itself to produce an ore deposit. The size of the deposits, their grades, and ratios of economic metals are very variable. Definition of magmatic segregation concentration of crystals of a particular mineral or minerals in certain parts of a magma during its cooling and crystallization. The magmatic deposits are classified into two major groups, viz. Iv chromiteplatinumgroup element magmatic deposits giorgio garuti encyclopedia of life support systems eolss electroplanting, and pharmaceutics. The genesis of different ore types and the mineralization processes of the jinchuan deposit remain controversial.
Because the focus of this paper is on nicupge deposits, type iii deposits will not be considered in much detail. During formation of the pegmatites a fluid phase separated and caused deuteric alteration under magmaticsubmagmatic conditions. Magmatic segregation article about magmatic segregation by. Magmatic origin of giant kirunatype apatiteironoxide. A magmatic ore deposit is an accumulation of magmatic minerals. In many cases it can be confirmed by a study of field relationships, from ore textures and from the results of experimental petrology that the ores have segregated during the crystallization of a magma. Ore group some deposit types and examples typical element associations komatiiteassociated nickel deposits mt keith, kambalda, widgiemooltha, maggie hays, jubilee. In advances in geology of the porphyry copper deposits. Pge deposit is one of the three largest magmatic ni deposits in the world. Magmatic segregation can also take place as a result of the separation of sulphide and silicate liquids.
General model of a zoned magmatic hydrothermal system showing poten tial linkages between a porphyry cu deposit centered on a composite porphyry intru sion at depth adapted from sillitoe, 1993. Pdf on nov 1, 2012, xieyan song and others published magmatic nicu and pge deposits. These include direct magmatic segregation or crystallization, magmatic hydrothermal replacement and hydrothermal precipitation in the sense of ironoxidecoppergold iocgtype deposits. Magmatic fluid segregation and overprinting hydrothermal processes in gabbro pegmatites of the neotethyan ophiolitic szarvasko complex bukk mountains, ne hungary. Decompression can be the result of active mantle upwelling such as in plumes, or. Sulfide segregation is influenced mainly by the nature of parental magma, crustal assimilation, fractional crystallization and sulfur content at sulfide saturation scss barnes and lightfoot, 2005, liu et al. Alkalic porphyry and epithermal deposits a view from. Magmatic nicupge deposits typically form by segregation of immiscible sulphide liquid from mafic to ultramafic magmas naldrett, 2004, and references therein.
Salient characteristics since the discovery of the jinchuan, limahe sichuan province, and hongqiling jilin province nicupge deposits during the 1950s to 1960s, several magmatic sul. Some of these minerals are extremely rare and almost never encountered in common rocks, an example being alloys of the platinum metals. Magmatic deposits 1 magmatic depositssulfides ni and cr pge 2. The formation of this type of magmatic deposits is related with segregation of sulfide melts by immiscibility from basaltic magmas e. Exploration for magmatic nicupge sulphide deposits. While a magma may start as a homogeneous liquid, magmatic segregation. Magmatic nicu sulfide deposits form as the result of the segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma and the partitioning of chalcophile elements.
This site is like a library, use search box in the widget to get ebook that you want. Some of the largest deposits, such as those in the sudbury district, ontario, canada, also occur along the base of a mafic intrusive at sudbury a basinshaped or funnellike norite intrusivebut their origin is disputed. Layered, ultramafic to mafic intrusions are uncommon in the geologic record, but host magmatic ore deposits containing most of the worlds economic concentrations of platinumgroup elements pge figs. The chemical principle governing precipitation of an immiscible liquid is the. Without magmatism and the chemical differentiation of magmas, life as we know it. Mar 24, 2017 shallow magma chambers either erupt as volcanoes or solidify as intrusive magma bodies. The early magmatic deposits resulted from straight magmatic processes those that have been termed orthotectic and orthomagmatic. The three most crucial factors for the formation of large and superlarge magmatic sulfide deposits are. Pge deposits are believed to have formed by segregation of immiscible sulfide melts andor alloys from maficultramafic magmas in dynamic magmatic systems such as lava channels, feeder dikes, and magma chambers. Magmatic differentiation an overview sciencedirect topics.
Cu auporphyry type deposits are commonly high, between 640 and. This paper summarizes research results of magmatic and hydrothermal biotites exemplified by the lakange porphyry cumo deposit and the qulong porphyry cu deposit in the gangdese porphyryskarn metallogenic belt, tibet. The type locality of hibonite is the esiva alluvial deposits, in tulear province, madagascar. Host rocks and parental magmas with the exception of the sudbury deposits, which formed in a crustal impact melt, magmatic nicupge deposits are hosted by a wide range of olivinebearing mantlederived. Presentation mode open print download current view. The best candidates for magmatic differentiation processes to form the footwall deposits of the south range are at little stobie, lindsley, the creighton 126 ore body, creighton deep, crean hill, mckim, and perhaps parts of the garson mineral system details are provided in chapter 4. Fundamentals of magmatic sulfide deposits magmatic nicu. A terrestrial magmatic hibonitegrossitevanadium assemblage. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. Geology, geochemistry, and genesis find, read and cite all the research you need on researchgate. The roles of volatiles in mineralizations of magmatic nicu.
Lightfoot5, nadya krivolutskaya6, bo wei7 6 1csiro mineral resources, perth, australia. Callinan mines declares exploration update chromite occurs as magmatic segregations in ultrabasic igneous rocks. Pdf how do metals escape from magmas to form porphyrytype. Original article magmatic nicupge deposits in magma plumbing systems. Chromite occurs in the host rock as masses, lenses, and dissemination.
Click download or read online button to get magmatic ore deposits book now. However, some of the mineralization in some deposits e. The relative roles of magmatic segregation, volcanic exhalation and regional metamorphism in the generation of volcanic associated nickel ores of western australia. These magma bodies are traditionally considered to be longlived and dominated by melt. Hydrothermal versus magmatic 14 hydrothermal versus magmatic. It is concluded that the high degree of partial melting i. Magmatic segregation is an oreforming process, in which the valuable minerals are concentrated by settling them out from cooling magma. Magmatic ore deposits in layered intrusionsdescriptive model. This indicates that magmatic segregation, which forms the nickelsulphide deposits we are looking for, may have occurred in this area. This paradigm helps explain many geophysical and geochemical. Magmatic sulfide deposits fall into two major groups when considered on the basis of the value of their contained metals, one group in which ni, and, to a lesser extent, cu, are the most valuable products and a second in which the pge are the most important. Genesis of the main types of sulphide ore in the jinchuan. These deposits are mined primarily for their platinum, palladium, and rhodium contents table 1.
Posted on october 20, 20 by economicgeo a colleague and i visited a university geology department in the vicinity of a project we were working to do a presentation on the geology of the project. A different kind of magmatic segregation involves liquid immiscibility. In the previous chapter we have described some of the mineral deposits that have formed by magmatic activity, often by segregation within the magma chamber itself. The processes of formation of mineral deposits are grouped. Magmatic deposits article about magmatic deposits by the. Other articles where magmatic segregation is discussed. This man survived over 2 months lost at sea 76 days adrift i shouldnt be alive s4 ep6 wonder duration. Discuss the mechanisms by which crystal fractionation could occur in. Ii processes of magma evolution and magmatic suites gerhard worner encyclopedia of life support systems eolss figure 1. The lorraine deposits appear to represent the deepest known level of ore formation in the alkalic porphyry environment. Pdf the relative roles of magmatic segregation, volcanic.
Ore deposits formed by gravity settling due to magmatic. The appropriate physical environment is required so that the sulfide liquid mixes with. Oil and gas are often associated with salt deposits, which can rise kilometers above the top of the main underground salt body. Magmatic fluid segregation and overprinting hydrothermal. Second, during the crystallization of magma valuable minerals may form earlier than others and sink to the bottom of the magma reservoir, forming early magmatic deposits. A magmatic model for the origin of large salt formations. Magmatic sulfide ore deposits are products of natural smelting. Clair state university of iowa follow this and additional works at. These are not ores that have segregated during crystallization of the magma but are those. In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The metal content of the sulphides is governed by the concentration of the metals in the silicate host magma, the sulphide meltsilicate melt. A magmatic model for the origin of large salt formations stef heerema large formations of rock salt are found on every continent around the world.
Ore deposits produced by magmatic segregation, with. Segregation of magmatic fluids and their potential in the. Vertically extensive and unstable magmatic systems. Features, formation and exploration xieyan songa, yushan wangb, liemeng chena a state key laboratory of ore deposit geochemistry, institute of geochemistry, chinese academy of sciences, guanshui road 46, guiyang 550002, china b jinchuan group limited, jinchuan road 98, jinchang, gansu 737104, china. Ore deposits produced by magmatic segregation, with special. These deposits are also called segregation or accumulative deposits chromium, titanium, and iron deposits. Rocks formed as a result of magmatic segregation are called magmatic cumulates. Mungall and others published magmatic ore deposits find, read and cite all the research you need on researchgate. Porphyry ore deposits are aproduct of magmatichydrothermal activity. Magmatic ore deposits download ebook pdf, epub, tuebl, mobi. Magmatic processes and the evolution of magmas throughout geological history have shaped the globe by forming the continents and providing nutrient elements in abundances that have made them important in the metabolism of plants and animals.
Droplets segregate due to settling to the base of the magma andor due to irregular magma flow. Many important elements are found, on average, in the crust in very small amounts ppm ppb finding these elements in high concentrations is the exception and requires unusual geologic processes. Magmatic segregation is a general term referring to any process by which one or more minerals become locally concentrated segregated during the cooling and crystallization of a magma. Kong, zhigang wu, yue liang, ting zhang, feng meng, xuyang lu, lin and yang, g. Sulfide ore deposits occupy a spectrum from accumulated pools of matte within small igneous intrusions or lava flows, mined primarily. About 7% of chromite ore production goes to the refractory industry. A cooling magma will sometimes precipitate droplets of a second magma that has an entirely different composition. Multiple constraints from chospbsr isotopic compositions.
Lecture 2processes and mode of formation processes of. Since the discovery in the mid1960s of nickel sulphide mineralization at kambalda in western australia, komatiites have been recognized as significant hosts of magmatic ni ores. Magmatic nicu sulfide deposits form as the result of segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma, and the partitioning of chalcophile elements into these from the silicate melt. Magmatic nicupge deposits in magma plumbing systems. The material was probably derived from nearby deposits of thorianitebearing skarns, which are widespread in the panafrican 565515 ma granulite belts of madagascar and tanzania rakotondrazafy et al.
Advances in research of mineral chemistry of magmatic and. Lkind of deposits lalmost all chromite deposits are magmatic segregation in ultrabasic rocks. Most major magmatic cunipge sulphide deposits are thought to have formed by segregation of an immiscible sulphide melt from a silicate host magma, in response to processes such as magma mixing, rapid cooling, differentiation, and contamination. Sources of oreforming material for pbzn deposits in the sichuanyunnanguizhou triangle area. Host rocks and parental magmas with the exception of the sudbury deposits, which formed in a crustal impact melt. Doi privacy policy legal accessibility site map contact usgs. Name 5 processes that might cause the chemical composition of a magma to change.
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