Magmatic concentration, hydrothermal solutions part 1. Oct 24, 2015 magmatic ore deposits part 2 duration. Magmatic nickelcopperplatinum group element deposits. If magmas are related to each other by some processes, that process would have to be one that causes magma composition to change. Magmatic segregation is an oreforming process, in which the valuable minerals are concentrated by settling them out from cooling magma. This chapter introduces magmatic sulphide ore deposits, assesses the controls. Mineral deposits mineral systems and mineralising events. Mineral deposite formed by magmatic concentration process products. These elements are the ones which did not fit well inside of common rock forming minerals. Lkind of deposits lalmost all chromite deposits are magmatic segregation in ultrabasic rocks. Much more uncommon than maficultramafic magmatic ore deposits.
The distribution and concentration of ree in these deposits are influenced by various rockforming processes including enrichment in magmatic or hydrothermal fluids, separation into. Ore deposits have formed at various periods over geological time from at least 3500 million years ago to the present day where mineral deposits are forming as part of natural earth processes both on land and on the seafloor. Ore deposits secondaryenrichment deposits original deposit is subeconomic. In addition, secondary processes can produce associated asbestos, soapstone, and native copper deposits. Ore deposits magmatic deposits crystal settling from magma. 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.
Triggers for the formation of porphyry ore deposits in. The formation of valuable minerals in magma that is cooling is. As a leading global manufacturer of crushing, grinding and mining equipments, we offer advanced, reasonable solutions for any sizereduction requirements including, mineral deposite formed by magmatic concentration process, quarry, aggregate, and different kinds of minerals. Gold concentrations of magmatic brines and the metal.
Magmatic ore deposits form through processes that are, for the most part, normal aspects. Sulfide ore deposits occupy a spectrum from accumulated pools of matte within small igneous intrusions or lava flows. In general, ore deposits of a metal are rocks in which the concentration of the metal is. Over the years, various process have been suggested to explain the variation of magma compositions observed within small regions. Volcanogenic massive sulfide ore deposits, also known as vms ore deposits, are a type of metal sulfide ore deposit, mainly copperzinc which are associated with and created by volcanicassociated hydrothermal events in submarine environments these deposits are also sometimes called volcanichosted massive sulfide vhms deposits. Through the magmatic segregation process, one or more minerals are concentrated locally during the cooling of magma. Form of the deposit size, shape, orientation and ore mineral distribution.
Clair state university of iowa follow this and additional works at. About 60% of the worlds ni and 40% of the worlds pge platinumgroupelementsare mined from magmatic sul. This paper explores the physical and chemical evolution of lowsalinity to mediumsalinity magmatic. Representatives of magmatic concentration are many and widespread, but the.
Associated host rocks or geological structures ore associations. The rocks that are formed as a result of magmatic segregation are called magmatic cumulates. Sulfide ore deposits occupy a spectrum from accumulated pools of matte within small igneous intrusions or lava flows, mined primarily for ni and. Sulfur concentration at sulfide saturation scss in.
This is a pdf file of an unedited manuscript that has been accepted for publication. Gold deposits can still be seen today forming in some active geothermal areas. In other instances the transvaal sedimentary rocks are. These include lowsulfide, contacttype, and reeftype pge deposits, chromite deposits, and fetiv deposits. Economic deposits require concentration by geologic processes. Magmatic nicu sulfide deposits form as the result of the segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma. Discrimination between magmatic and hydrothermal nicupge. Ore deposits formed by gravity settling due to magmatic. Triggers for the formation of porphyry ore deposits in magmatic arcs jamie j. What is the use of a classification of mineral deposits. The feasibility of extracting an element depends on the concentration and mineralogy of the element in the host mineral or rock. There are six worldclass settings for magmatichydrothermal gold deposits. These deposits vary in shape and occur in igneous rocks that are related to them in origin.
The host rock for the mineralization can range from ultramafic to felsic. Magmatic sulfide ore deposits elements geoscienceworld. Geological knowledge of earths crust and mineral formations. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Magmatic deposits article about magmatic deposits by the.
Lall economic deposits of chromite are in ultrabasicrocks and are either stratiform in layered intrusions 98% of worlds chromite resources or podiform. Portrait of a planet fifth edition chapter 15 mineral resources cesc 1011020110. The early magmatic deposits are believed to have been formed simultaneously with the hostrock, whereas the late magmatic deposits are formed towards the close of the magmatic deposits. Magmatic nicupge sulfide deposits can occur with a number of other magmatic ore deposits. No layering due to 100 higher mew, also due to lower density differences between minerals. Secondary enrichment processes allow concentration of the ore minerals to economic levels. Kaneko encyclopedia of life support systems eolss size and richness to constitute valuable mineral deposits such as chromium, platinum and ree. Mineral deposite formed by magmatic concentration process. Differentiation causes a concentrating effect resulting in a concentration of selected elements in the residual magma. Volcanogenic massive sulfide ore deposit wikipedia. Comments on genesis although still regarded as controversial, intrusion related gold deposits irgd. Introduction ore deposits are crustal concentrations of useful elements that can be exploited at a pro. A number of processes that occur during cooling and crystallization of magmatic bodies can lead to the separation and concentration of minerals. Examples of concentrating and transporting agents are groundwater, seawater, and magma.
The average grade of an ore deposit is calculated, often employing very sophisticated. The processes of formation of mineral deposits are grouped. These deposits are mined primarily for their platinum, palladium, and rhodium contents table 1. These results demonstrate that the experimental duration needed to reach steady state is under 6 h. Magmatic ore deposits are derived from accumulations of crystals of metallic oxides, or immiscible sulfide, or oxide liquids that formed during the cooling and crystallization of magma, typically with mafic to ultramafic compositions.
Mineral deposit mineral deposit magmatic cumulates. Students who gain less than 40% in the exam will be considered to have failed the course, irrespective of the semestermodule mark. Magmatic nicupge deposits in magma plumbing systems. 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. Various theories of ore genesis explain how the various types of mineral deposits form within the earths crust. Complexes segregated via magmatic processes and was subsequently modified by hydrothermal processes.
The formation temperature of different magmatic deposits varies from 1500c to 300c. Magmatic ore deposits magmatic ore deposits are those which are formed during crystallization of a magma, deep underground. Wilkinson 1, 2, 3 nature geoscience volume 6, pages 917 925 20 cite this article. Oct, 20 triggers for the formation of porphyry ore deposits in magmatic arcs jamie j. They occur within theigneous rock from which they were derived, such as a gabbro.
Magmatic some mineral deposits, particularly those containing ni, cr and pt, form by the separation of the metal sulphide or oxides in the molten form, within an igneous melt before it crystallizes. It remains controversial, however, whether the metal content of porphyrystyle and other magmatichydrothermal deposits is dominantly controlled by metal partitioning between magma and an. The formation of the magmatic sulfide deposits in magma conduit systems, such as the norilsk nicupge deposit, voiseys bay nicuco deposit, and the magmatic sulfide deposits at the bases of komatiite flow, and the pge deposits in large layered intrusions, such as the bushveld intrusion and great dyke, are closely related to mantle. Magmatic segregation, or separation and concentration of the ore from the cooling, crystallizing rock magma, has taken place where the magma has pushed its way upward and formed large masses laccoliths, etc. Magma is molten rock, together with any suspended mineral grains and dissolved gases, that forms when temperatures rise and melting. This work has been identified with a creative commons public domain mark 1. Ore deposits produced by magmatic segregation, with. The property hosts the sunday lake intrusion, which is part of the proterozoic midcontinental rift magmatic event that produced the eagle nickel deposit in michigan lundin mining and the tamarack rio tinto talon resources and duluth complex antofagasta plc magmatic sulphide deposits in minnesota. Mineral deposits form because some medium serves as a concentrating and transporting agent for the ore minerals, and some process subsequently causes the transporting agent to precipitate, or deposit, the minerals. Portrait of a planet fifth edition university of notre dame. For the two fluids to always mix at the same place for an.
These deposits can form when dissolution occurs in oxygenated waters and the water moves to a deoxygenated region. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. Start studying ore deposits formed by gravity settling due to magmatic segregation. Mineral deposits form in a variety of complex geologic settings such as continental magmatic arcs, sedimentary basins, and evaporite deposits. Magmatic ore deposits in layered intrusionsdescriptive. Mineral deposit mineral deposit formation of mineral deposits. For the observed metal concentration of up to 20 wt % sn in the yankee lode to be produced. From the days of agricola, the founder of the science of ore deposits, successive authors on the subject have attempted classifications, none of which have attained unanimous endorsement of miners, engineers, or geologists. Potential for magmaticrelated uranium mineral systems in australia 3 this study employs a mineral systems approach which has been modified from the five questions developed by the predictive mineral discovery cooperative research centre walshe et al. Rocks formed as a result of magmatic segregation are called magmatic cumulates. Magmatic deposits containing exploitable quantities of nickel, copper, and platinum group elements pge are associated with variable quantities of localized sulphide concentrations in mafi c and. Magmatic definition of magmatic by the free dictionary. As magma crystallizes, these elements remain in the magma and their concentration increases. Oregenesis theories vary depending on the mineral or commodity examined oregenesis theories generally involve three components.
Magmatic sulfide ore deposits are products of natural smelting. If you continue browsing the site, you agree to the use of cookies on this website. Sulfide ore deposits occupy a spectrum from accumulated pools of matte within small igneous intrusions or lava flows, mined primarily for ni and cu. With theriseof manydeveloping nations, the worlds need for metal deposits increased rapidly in. Deposits have commonly formed through a combination of geological factors closely related in time. Ore deposits produced by magmatic segregation, with special.
The deposit can consist of massive ores in some cases, a nd disseminations of rare minerals in others. Some igneous rocks enriched in incompatible elements be, li, rare earth elements, u, th, rb, au elements that don. Name 5 processes that might cause the chemical composition of a magma to change. Structural control, magmatichydrothermal evolution and. Gold concentrations of magmatic brines and the metal budget. The magmatic deposits are classified into two major groups, viz. Magmatic ore deposits in layered intrusionsdescriptive model for.
Potential for magmaticrelated uranium mineral systems in. As we know, magma consists of a multitude of constituents, which are in mutual solution. Any process that causes magma composition to change is called magmatic differentiation. Gold mineralisation stage fluids range from magmatic to dominantly magmatic with variable amounts of external or unexchanged waters, probably introduced into the hydrothermal system during cooling. The most important beds in magmatic deposits are those of iron, titanium, vanadium, chromium, platinum, copper, nickel, cobalt, apatite, diamonds, niobiumtantalum, zirconium, and hafnium. Longo2 the eocene epoch in the great basin of western north america was a period of profuse magmatism and hydrothermal activity. Chromite occurs in the host rock as masses, lenses, and dissemination. Discuss the mechanisms by which crystal fractionation could occur in nature. Copper deposits 3platinum group metal pgm deposits. 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. Mineral deposit formation of mineral deposits britannica.
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. Magmatic deposits prospecting guidelines magmatic deposits prospecting guidelines abridged and adapted to html from notes from the prospecting school on the web by luca riccio for the b. Only students with a semestermodule mark of more than 50% and an exam mark of more than 35% will be. As the magma approaches the earths surface its temperature and the external pressure drop, with the result of crystallization and differentiation of minerals in a definite sequence. Magmatichydrothermal origin of nevadas carlintype gold. Magmatic deposits deposits of minerals formed deep in the earths crust during the solidification and crystallization of basic or alkaline magma containing high concentrations of valuable minerals. In some localities andalusite forms economically exploitable concentrations oosterhuis. Possible in certain deposits associated with mafic magmas. Magmatichydrothermal origin of nevadas carlintype gold deposits john l. Magmatic ore deposits in layered intrusionsdescriptive model.
Much less frequently magmatic deposits may occur in the form of flows that issue from volcanic vents for example, volcanic sulfur flows. Sulfur concentration at sulfide saturation scss in magmatic. Ore deposits produced by magmatic segregation, with special reference to the nickel ores of the sudbury district, ontario stuart st. Magmatic sulfiderich nickelcopper deposits related to.
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