They eventually create richmetallic fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals. An ore deposit, in its simplest terms, is a portion of the earths crust from which some industrial raw material can be extracted at a profit. Classification of ore deposits rock geology minerals. The details will be debated until the sun cools, but the broadbrush classification of mineral deposits is generally understood. For example, if the average grade of a porphyry deposit is 0. Ore deposits formed by lateral secretion are formed by metamorphic reactions during shearing, which liberate mineral constituents such as quartz, sulfides, gold, carbonates, and oxides from deforming rocks, and focus these constituents into zones of reduced pressure or dilation such as faults. Only students with a semestermodule mark of more than 50% and an exam mark of more than 35% will be. Geology and ore deposits of the shafter mining district, presidio county, texas by clyde p. Geologists, are known to have more opinions than economists, so it should come as no surprise that the classification of mineral deposits, is an ongoing hot topic. Hydrothermal mineral deposit, any concentration of metallic minerals formed by the precipitation of solids from hot mineralladen water hydrothermal solution.
The authors comprehensively describe the physical and chemical characteristics of ore deposits, and correlate them with environments and conditions of deposition since ore deposits are best interpreted as extensions of the environments responsible for their enclosing rocks. Four groups of sources of the water of hydrothermal solutions are distinguished. Evolution of ore deposits and technology transfer project usgs. This chapter on metamorphosed hydrothermal ore deposits summarizes key attributes of mineral deposits that are hydrothermal in nature, originally formed at shallow crustal depths, entrained in. Isbn 0716714566 background paper the outlook for metals markets prepared for g20 deputies meeting sydney 2006 pdf. To the first or contactmetamorphic class belong the deposits worked by the bluestone, mason valley, and other mines. Magmatic ore deposits magmatic ore deposits are those which are formed during crystallization of a magma, deep underground.
Therefore, ore deposits by definition form only where geological processes concentrate elements into ore minerals, and then concentrate the latter again into a single, and limited, location. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. Ore deposit geology john ridley, colorado state university. Classification of mineral deposits geology for investors.
Fluid inclusions fi represent the best tool available for determining temperatures and pressures of ore forming processes and provide the only direct method for determining compositions of ore. Nevertheless, its formation required the operation of read more. Interpretation of ore textures and paragenetic sequences. Ore deposits ore is a metalliferous mineral, or an aggregate of metalliferous minerals, more or less mixed with gangue non ore, wall rock or waste rock which from the standpoint of the metallurgist can be treated at a profit. Komatiiteassociated nickel deposits layered maficultramafic intrusion deposits skarn deposits fractionated granitoidassociated deposits porphyryassociated deposits iron oxide copper gold deposits syndeformational hydrothermal and replacement deposits orogenic gold deposits carbonatehosted stratabound leadzinc deposits.
If youve been searching for a modern textbook on metallic ore deposits, this is a good choice. In the first half of the 20th century such geologists as v lindgren 8 and v obruchev 4. The enrichment process of these metals follows physical principles that are similar to the extraction of deep geothermal energy by hydraulic fracturing of the rock. Sedex, or sedimentary exhalative deposits, are ore deposits formed when hydrothermal.
This may occur without much hydrothermal fluid flow. Hydrothermal gold deposits epithermal, carlintype, and orogenic have accounted for 75% of lodegold production. Other sources of heating that may be involved include energy released by radioactive decay or by faulting of the. Sulfide deposits are by far the most important source of nickel, both quantitatively and numerically. As an example of early classification of hydrothermal ore deposits, here is enclosed lindgrens evans, 1993 classification based on approximate t empe ra t ure s of f orm at ion. For best results viewing and printing pdf documents, it. Petrology of ore deposits university of south alabama. Aug 31, 20 ore deposit geology by john ridley, 9781107022225, available at book depository with free delivery worldwide. If a deposit area has 6 tons of copper in 1,000 tons of ore rock, what is the grade. Komatiiteassociated nickel deposits layered maficultramafic intrusion deposits skarn deposits fractionated granitoidassociated deposits porphyryassociated deposits iron oxide copper gold deposits syndeformational hydrothermal and replacement deposits orogenic gold deposits carbonate. In 1964 two single districts of sulfide deposits in canada were producing about 80 percent of the free world total. Emmons for suggestions in connection with the sections on ore deposits.
Role of magmatic activity in the generation of ore deposits mdpi. For this type of deposit we may ask the following types of questions. The 85 descriptive deposit models and 60 gradetonnage models presented here are the culmination of a process that began in. In some occurrences, minerals can be extracted at a profit by mining. Industrial drive chelsea, mi 48118 additional copies of this publication can be obtained from society of economic geologists, inc. Syngenetic ore deposits ore deposits which are formed as the same time as the enclosing rock, are called syngenetic ore deposits. Ore deposit an accumulation of an ore body or ore bodies on or below the surface of the earth that, because of size, quality, and mode of occurrence, is suitable for industrial exploitation.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. The ores found in the pitches and flats bear evidence of having been formed mainly in open spaces. Geology, ore deposits, and mineral potential of the seward peninsula, alaska by c. From the integration of field and laboratory data petrography, isotope geochemistry, fluid inclusion and organic matter studies and numeric simulations the research group aims to understand the role of the fluids in the formation of ore deposits and the. The study of ore deposits through the last century has required and. Hydrothermal copper deposits are often found in porphyritic igneous rocks. He must also have a complete knowledge of the method of making. The mining companies, and the resi dents of republic and vicinity offered every. Ore minerals minerals with economic value are ore minerals minerals often associated with ore minerals but which do not have economic value are gangue minerals key to economic deposits are geochemical traps metals are transported and precipitated in a very concentrated fashion gold is almost 1,000,000 times less abundant than is iron economic. A number of ore deposits are formed as the result of hydrothermal processes in the earth crust. Oct 22, 2017 introduction the purpose of any classification is to group similar objects into classes or sets either for convenience, organization, or access, as in a collection,a library, or a computer data base, or for the purpose of learning more about the items being classified. Ore minerals, mineral deposits and processes of their formation. The solutions are thought to arise in most cases from the action of deeply circulating water heated by magma.
Metamorphosed hydrothermal ore deposits request pdf. Holmov 1931 after describing the succession of vein formation, which starts with a pegmatite period, in the duldurga tungsten deposit. Geology of ore deposits rg journal impact rankings 2018. Economic consideration principal steps in the establishment and operation of a mine. The enrichment of ore deposits william harvey emmons. Introduction the purpose of any classification is to group similar objects into classes or sets either for convenience, organization, or access, as in a collection,a library, or a computer data base, or for the purpose of learning more about the items being classified. Hydrothermal deposits article about hydrothermal deposits.
However, on this case, such precise and accurate classifications would completely depend on the information data of ore formation conditions. Fluid inclusions in hydrothermal ore deposits the coupled geochemistry of au and as in pyrite from hydrothermal ore deposits. Skinner, editor first edition, 1999 graphic design and layout by johnson printing boulder, co printed by sheridan books, inc. Yager chapter e3 of integrated investigations of environmental effects of historical mining in the animas river watershed, san juan county. Major styles of mineralization and hydrothermal alteration and related solid and aqueousphase geochemical signatures by dana j. Volcanogenic massive sulfides vms and sedimentary exhalative deposits part 7 duration.
Types of hydrothermal ore forming systems from fluid inclusion studies article pdf available in geology of ore deposits 406. Major styles of mineralization and hydrothermal alteration. From the integration of field and laboratory data petrography, isotope geochemistry, fluid inclusion and organic matter studies and numeric simulations the research group aims to understand the role of the fluids in the formation of ore deposits and the relationship between the mineralizing. All the significant types of nickel ore deposits are represented in north america. Ore deposit article about ore deposit by the free dictionary. Classification of ore deposits linkedin slideshare. Mineralogy and petrography of ore and gangue minerals under the reflected and transmitted light microscope and in hand specimen.
Incorporating recent observational and theoretical advances, excellent graphics, an accessible treatment of chemical processes, and end of chapter questions, this book appears ideal for undergraduate geology majors. May 16, 2018 a number of ore deposits are formed as the result of hydrothermal processes in the earth crust. Classification of ore deposits by abdul bari qanit m. By leia michele toovey exclusive to copper investing news. A list to some major types of ore deposits and a link book download.
Then he must be thoroughly familiar with the many and varied species of earths, juices, gems, stones, marbles, rocks, metals and compounds. Geochemistry of hydrothermal ore deposits pdf free download. Page 95 dubuque,a and yielded large quantities of galena ore. A similar body of galena was found in a welldeveloped pitch at elizabeth in 1903, and is described on page 80. These accumulations develop either as a result of the transport of oreforming elements. The details will be debated until the sun cools, but the broadbrush.
Hypot her mal 300 600 ec, mes o t h er mal 200 300 ec. However, ore formation in the interior of modern hydrothermal magmatic systems is either declared on the basis of indirect data stties of volcanic gases and udy of metal bearing proper. Jul 29, 20 geologists, are known to have more opinions than economists, so it should come as no surprise that the classification of mineral deposits, is an ongoing hot topic. New computer simulations by geologists from eth zurich demonstrate how large copper and gold deposits are formed. Introduction ore deposits are crustal concentrations of useful elements that can be exploited at a pro. Although these deposits form in distinctly different geologic settings and by. Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in earths crust through fractures. Ore deposits are divided into deposits of ferrous, light, nonferrous, noble, rare, and radioactive metals and deposits of trace elements. Ore deposits hydrothermal deposits disseminated deposit. Evolution of ore deposits and technology transfer project. Page 231 replacement of limestone and genetically associated with metamorphism of a kind usually attributed to the contact action of intrusive rock, 2 metasomatic vein deposits in altered limestone, and 3 metasomatic vein deposits in granodiorite.
The deposit can consist of massive ores in some cases, and disseminations of rare minerals in others. Geological characteristics and distribution of ore deposits, including deposits of base and precious metals, diamonds, and industrial minerals. It is assumed that there is relation between geothermal and epithermal ore deposits hedenquist et al. Ore deposit crossword clue answer crossword heaven. Iv characteristics of mineral deposits maria boni encyclopedia of life support systems eolss and seams in the rocks.
The host rock for the mineralization can range from ultramafic to felsic. Modern civilizations dependence upon an increasing volume and diversity of minerals makes the search for new ore deposits ever more difficult. Students who gain less than 40% in the exam will be considered to have failed the course, irrespective of the semestermodule mark. Distribution of mineral deposits in various geotectonic s settings and mineralization epochs. An ore deposit may also form as a result of several steps of processes that are identical but belong to different periods of geological history. A common type of ore deposit is the one formed by actions of hot water, the hydrothermal type. Sedex, or sedimentary exhalative deposits, are ore deposits formed when hydrothermal fluids enter a water reservoir, such as an ocean. If a deposit area has 200lbs of copper in 10,000lbs of ore rock, what is the grade. Part or all of this report is presented in portable document format pdf. Request pdf on jan 1, 2005, andy wilde and others published descriptive ore deposit models.
Ore deposit geology by john ridley, 9781107022225, available at book depository with free delivery worldwide. If we understand how these processes work, we may be able to find more ore deposits. Pete sainsbury l introduction the writer first began geologic studies on the seward peninsula in 1952. Ross abstract the shafter mining district is principally notable for the presidio mine, which. Fantastic summary, covering the majority of deposit types in good detail but should be supplemented with more recent andor detailed scientific papers.
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