Editing Ore (section)

== Ore deposits ==
{{Main|Mineral resource classification}}

An ore deposit is an economically significant accumulation of minerals within a host rock.<ref>{{Citation |last1=Heinrich |first1=C. A. |title=13.1 – Fluids and Ore Formation in the Earth's Crust |date=2014-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780080959757011013 |work=Treatise on Geochemistry (Second Edition) |pages=1–28 |editor-last=Holland |editor-first=Heinrich D. |access-date=2023-02-10 |place=Oxford |publisher=Elsevier |language=en |isbn=978-0-08-098300-4 |last2=Candela |first2=P. A. |editor2-last=Turekian |editor2-first=Karl K.}}</ref> This is distinct from a mineral resource in that it is a mineral deposit occurring in high enough concentration to be economically viable.<ref name="Hustrulid22" /> An ore deposit is one occurrence of a particular ore type.<ref name="JORCCODE2">{{cite book |last1=Joint Ore Reserves Committee |url=http://www.jorc.org/docs/jorc_code2012.pdf |title=The JORC Code 2012 |date=2012 |edition=2012 |pages=44 |access-date=10 June 2020}}</ref> Most ore deposits are named according to their location, or after a discoverer (e.g. the [[Kambalda type komatiitic nickel ore deposits|Kambalda]] nickel shoots are named after drillers),<ref>{{cite news |last1=Chiat |first1=Josh |date=10 June 2021 |title=These secret Kambalda mines missed the 2000s nickel boom – meet the company bringing them back to life |work=Stockhead |url=https://stockhead.com.au/resources/kambalda-nickel-boom-lunnon/ |access-date=24 September 2021}}</ref> or after some whimsy, a historical figure, a prominent person, a city or town from which the owner came, something from mythology (such as the name of a god or goddess)<ref>{{cite news |last1=Thornton |first1=Tracy |date=19 July 2020 |title=Mines of the past had some odd names |agency=Montana Standard |url=https://mtstandard.com/lifestyles/mines-of-the-past-had-some-odd-names/article_efce26cc-a021-5493-b4ed-834aa6fe0dfe.html |access-date=24 September 2021}}</ref> or the code name of the resource company which found it (e.g. MKD-5 was the in-house name for the [[Mount Keith Mine|Mount Keith nickel sulphide deposit]]).<ref>{{cite journal |last1=Dowling |first1=S. E. |last2=Hill |first2=R. E. T. |date=July 1992 |title=The distribution of PGE in fractionated Archaean komatiites, Western and Central Ultramafic Units, Mt Keith region, Western Australia |journal=Australian Journal of Earth Sciences |volume=39 |issue=3 |pages=349–363 |bibcode=1992AuJES..39..349D |doi=10.1080/08120099208728029}}</ref>

=== Classification ===
{{Main|Ore genesis}}

Ore deposits are classified according to various criteria developed via the study of economic geology, or [[ore genesis]]. The following is a general categorization of the main ore deposit types:

=== Magmatic deposits ===

Magmatic deposits are ones who originate directly from magma[[File:Grainitic Pegmatite.jpg|thumb|244x244px|Granitic pegmatite composed of plagioclase and K-feldspar, large hornblende crystal present. Scale bar is 5.0 cm]]
* [[Pegmatite]]s are very coarse grained, igneous rocks. They crystallize slowly at great depth beneath the surface, leading to their very large crystal sizes. Most are of granitic composition. They are a large source of industrial minerals such as [[quartz]], [[feldspar]], [[spodumene]], [[petalite]], and [[Lithophile element|rare lithophile elements]].<ref>{{Cite journal |last=London |first=David |date=2018 |title=Ore-forming processes within granitic pegmatites |url=https://www.sciencedirect.com/science/article/pii/S0169136818300283 |journal=Ore Geology Reviews |language= |volume=101 |pages=349–383 |doi=10.1016/j.oregeorev.2018.04.020 |bibcode=2018OGRv..101..349L |issn=0169-1368}}</ref>
* [[Carbonatite]]s are an igneous rock whose volume is made up of over 50% carbonate minerals. They are produced from mantle derived magmas, typically at continental rift zones. They contain more [[Rare-earth element|rare earth elements]] than any other igneous rock, and as such are a major source of light rare earth elements.<ref name="Verplanck-2016">{{Cite book |last1=Verplanck |first1=Philip L. |url=https://pubs.er.usgs.gov/publication/70138176 |title=Rare earth and critical elements in ore deposits |last2=Mariano |first2=Anthony N. |last3=Mariano Jr |first3=Anthony |publisher=Society of Economic Geologists, Inc. |year=2016 |isbn=978-1-62949-218-6 |location=Littleton, CO |pages=5–32 |chapter=Rare earth element ore geology of carbonatites |oclc=946549103}}</ref>
* Magmatic [[Sulfide mineral|Sulfide]] Deposits form from mantle melts which rise upwards, and gain sulfur through interaction with the crust. This causes the sulfide minerals present to be immiscible, precipitating out when the melt crystallizes.<ref name="Naldrett-2011">{{Cite book |last=Naldrett |first=A. J. |title=Magmatic Ni-Cu and PGE Deposits: Geology, Geochemistry, and Genesis |publisher=Society of Economic Geologists |year=2011 |isbn=9781934969359 |chapter=Fundamentals of Magmatic Sulfide Deposits}}</ref><ref name="Song-2011">{{Cite journal |last1=Song |first1=Xieyan |last2=Wang |first2=Yushan |last3=Chen |first3=Liemeng |date=2011 |title=Magmatic Ni-Cu-(PGE) deposits in magma plumbing systems: Features, formation and exploration |journal=Geoscience Frontiers |language= |volume=2 |issue=3 |pages=375–384 |doi=10.1016/j.gsf.2011.05.005|bibcode=2011GeoFr...2..375S |doi-access=free }}</ref> Magmatic sulfide deposits can be subdivided into two groups by their dominant ore element:
** Ni-Cu, found in [[komatiite]]s, [[anorthosite]] complexes, and [[flood basalt]]s.<ref name="Naldrett-2011" /> This also includes the [[Sudbury Basin|Sudbury Nickel Basin]], the only known astrobleme source of such ore.<ref name="Song-2011" />
** [[Platinum group elements|Platinum Group Elements]] (PGE) from large [[mafic]] intrusions and [[Tholeiitic magma series|tholeiitic]] rock.<ref name="Naldrett-2011" />
* Stratiform Chromites are strongly linked to PGE magmatic sulfide deposits.<ref name="Schulte-2010">{{Cite journal |last1=Schulte |first1=Ruth F. |last2=Taylor |first2=Ryan D. |last3=Piatak |first3=Nadine M. |last4=Seal |first4=Robert R. |date=2010 |title=Stratiform chromite deposit model |url=http://dx.doi.org/10.3133/ofr20101232 |journal=Open-File Report |page=49 |doi=10.3133/ofr20101232 |bibcode=2010usgs.rept...49S |issn=2331-1258}}</ref> These highly mafic intrusions are a source of [[chromite]], the only [[chromium]] ore.<ref name="Mosier-2012">{{Cite journal |last1=Mosier |first1=Dan L. |last2=Singer |first2=Donald A. |last3=Moring |first3=Barry C. |last4=Galloway |first4=John P. |date=2012 |title=Podiform chromite deposits—database and grade and tonnage models |journal=Scientific Investigations Report |publisher=USGS |pages=i–45 |doi=10.3133/sir20125157 |issn=2328-0328|doi-access=free |bibcode=2012usgs.rept...71M }}</ref> They are so named due to their strata-like shape and formation via layered magmatic injection into the host rock. Chromium is usually located within the bottom of the intrusion. They are typically found within intrusions in continental cratons, the most famous example being the [[Bushveld complex|Bushveld Complex]] in South Africa.<ref name="Schulte-2010" /><ref>{{Citation |last=Condie |first=Kent C. |title=Tectonic settings |date=2022 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780128199145000020 |work=Earth as an Evolving Planetary System |pages=39–79 |access-date=2023-03-03 |publisher=Elsevier |language=en |doi=10.1016/b978-0-12-819914-5.00002-0 |isbn=978-0-12-819914-5}}</ref>
* [[Podiform|Podiform Chromitites]] are found in ultramafic oceanic rocks resulting from complex magma mixing.<ref name="Arai-1997"/> They are hosted in serpentine and dunite rich layers and are another source of chromite.<ref name="Mosier-2012" />
* [[Kimberlite]]s are a primary source for diamonds. They originate from depths of 150&nbsp;km in the mantle and are mostly composed of crustal [[xenocryst]]s, high amounts of magnesium, other trace elements, gases, and in some cases diamond.<ref name="Giuliani-2019"/>
[[File:Kimberliite.jpg|thumb|260x260px|Piece of kimberlite. 11.1 cm x 4.5 cm]]

=== Metamorphic deposits ===
These are ore deposits which form as a direct result of metamorphism.
* [[Skarn]]s occur in numerous geologic settings worldwide.<ref name="Meinert-1992">{{Cite journal |last=Meinert |first=Lawrence D. |date=1992 |title=Skarns and Skarn Deposits |url=https://journals.lib.unb.ca/index.php/GC/article/view/3773 |journal=Geoscience Canada |language= |volume=19 |issue=4 |issn=1911-4850}}</ref> They are silicates derived from the recrystallization of carbonates like [[limestone]] through [[Contact metamorphic|contact]] or [[regional metamorphism]], or fluid related [[Metasomatism|metasomatic]] events.<ref name="Einaudi-1981">{{Cite book |last1=Einaudi |first1=M. T. |url=https://www.worldcat.org/oclc/989865633 |title=Economic Geology Seventy-fifth anniversary volume |last2=Meinert |first2=L. D. |last3=Newberry |first3=R. J. |publisher=Society of Economic Geologists |others=Brian J. Skinner, Society of Economic Geologists |year=1981 |isbn=978-1-934969-53-3 |edition=75th |location=Littleton, Colorado |chapter=Skarn Deposits |oclc=989865633}}</ref> Not all are economic, but those with potential value are classified depending on the dominant element such as Ca, Fe, Mg, or Mn among many others.<ref name="Meinert-1992" /><ref name="Einaudi-1981" /> They are one of the most diverse and abundant mineral deposits.<ref name="Einaudi-1981" /> As such they are classified solely by their common mineralogy, mainly [[garnet]]s and [[pyroxene]]s.<ref name="Meinert-1992" />
* [[Greisen]]s, like skarns, are a metamorphosed silicate, quartz-mica mineral deposit. Formed from a granitic [[protolith]] due to alteration by intruding magmas, they are large ore sources of [[tin]] and [[tungsten]] in the form of [[wolframite]], [[cassiterite]], [[stannite]] and [[scheelite]].<ref name="Pirajno-1992">{{Cite book |last=Pirajno |first=Franco |url=https://www.worldcat.org/oclc/851777050 |title=Hydrothermal Mineral Deposits : Principles and Fundamental Concepts for the Exploration Geologist |date=1992 |publisher=Springer Berlin Heidelberg |isbn=978-3-642-75671-9 |location=Berlin, Heidelberg |oclc=851777050}}</ref><ref>{{Cite book |last=Manutchehr-Danai |first=Mohsen |url=https://www.worldcat.org/oclc/646793373 |title=Dictionary of gems and gemology |date=2009 |publisher=Springer |others=Christian Witschel, Kerstin Kindler |isbn=9783540727958 |edition=3rd |location=Berlin |oclc=646793373}}</ref>

=== Porphyry copper deposits ===

These are the leading source of copper ore.<ref name="Hayes-2015">{{Cite journal |last1=Hayes |first1=Timothy S. |last2=Cox |first2=Dennis P. |last3=Bliss |first3=James D. |last4=Piatak |first4=Nadine M. |last5=Seal |first5=Robert R. |date=2015 |title=Sediment-hosted stratabound copper deposit model |journal=Scientific Investigations Report |page=147 |doi=10.3133/sir20105070m |issn=2328-0328|doi-access=free |bibcode=2015usgs.rept...40H }}</ref><ref name="Lee-2020">{{Cite journal |last1=Lee |first1=Cin-Ty A |last2=Tang |first2=Ming |date=2020 |title=How to make porphyry copper deposits |journal=Earth and Planetary Science Letters |language= |volume=529 |page=115868 |doi=10.1016/j.epsl.2019.115868|bibcode=2020E&PSL.52915868L |s2cid=208008163 |doi-access=free }}</ref> [[Porphyry copper deposit]]s form along [[Convergent boundary|convergent boundaries]] and are thought to originate from the partial melting of subducted oceanic plates and subsequent concentration of Cu, driven by oxidation.<ref name="Lee-2020" /><ref>{{Cite journal |last1=Sun |first1=Weidong |last2=Wang |first2=Jin-tuan |last3=Zhang |first3=Li-peng |last4=Zhang |first4=Chan-chan |last5=Li |first5=He |last6=Ling |first6=Ming-xing |last7=Ding |first7=Xing |last8=Li |first8=Cong-ying |last9=Liang |first9=Hua-ying |date=2016 |title=The formation of porphyry copper deposits |url=http://link.springer.com/10.1007/s11631-016-0132-4 |journal=Acta Geochimica |language= |volume=36 |issue=1 |pages=9–15 |doi=10.1007/s11631-016-0132-4 |s2cid=132971792 |issn=2096-0956}}</ref> These are large, round, disseminated deposits containing on average 0.8% copper by weight.<ref name="Wills-2015" />

'''Hydrothermal'''[[File:Classic_VMS_Deposit2.png|thumb|A cross-section of a typical [[Volcanogenic massive sulfide ore deposit|volcanogenic massive sulfide]] (VMS) ore deposit]] [[Hydrothermal mineral deposit|Hydrothermal deposits]] are a large source of ore. They form as a result of the precipitation of dissolved ore constituents out of fluids.<ref name="Jenkin-2014" /><ref name="FutMinRes2">Arndt, N. and others (2017) Future mineral resources, Chap. 2, Formation of mineral resources, [https://www.geochemicalperspectives.org/online/v6n1/ Geochemical Perspectives, v6-1, p. 18–51].</ref>
* [[Mississippi Valley-Type]] (MVT) deposits precipitate from relatively cool, basal brinal fluids within carbonate strata. These are sources of [[lead]] and [[zinc]] sulphide ore.<ref name="Leach-2001"/>
* Sediment-Hosted Stratiform Copper Deposits (SSC) form when copper sulphides precipitate out of brinal fluids into sedimentary basins near the equator.<ref name="Hayes-2015" /><ref>{{Cite journal |last1=Hitzman |first1=M. W. |last2=Selley |first2=D. |last3=Bull |first3=S. |date=2010 |title=Formation of Sedimentary Rock-Hosted Stratiform Copper Deposits through Earth History |url=http://dx.doi.org/10.2113/gsecongeo.105.3.627 |journal=Economic Geology |volume=105 |issue=3 |pages=627–639 |doi=10.2113/gsecongeo.105.3.627 |bibcode=2010EcGeo.105..627H |issn=0361-0128}}</ref> These are the second most common source of copper ore after porphyry copper deposits, supplying 20% of the worlds copper in addition to silver and cobalt.<ref name="Hayes-2015" />
* [[Volcanogenic massive sulfide ore deposit|Volcanogenic massive sulphide]] (VMS) deposits form on the seafloor from precipitation of metal rich solutions, typically associated with hydrothermal activity. They take the general form of a large sulphide rich mound above disseminated sulphides and viens. VMS deposits are a major source of [[zinc]] (Zn), [[copper]] (Cu), [[lead]] (Pb), [[silver]] (Ag), and [[gold]] (Au).<ref name="Galley-2007" />[[File:Gold-Quartz-273364.jpg|thumb|[[Gold]] ore (size: 7.5 × 6.1 × 4.1&nbsp;cm)]]
* [[SEDEX|Sedimentary exhalative sulphide deposits]] (SEDEX) are a copper sulphide ore which form in the same manor as VMS from metal rich brine but are hosted within sedimentary rocks and are not directly related to volcanism.<ref name="Pirajno-1992" /><ref>{{Citation |last=Hannington |first=Mark |title=VMS and SEDEX Deposits |date=2021 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780081029084000758 |encyclopedia=Encyclopedia of Geology |pages=867–876 |access-date=2023-03-03 |publisher=Elsevier |language=en |doi=10.1016/b978-0-08-102908-4.00075-8 |isbn=978-0-08-102909-1|s2cid=243007984 }}</ref>
* [[Orogenic gold deposit]]s are a bulk source for gold, with 75% of gold production originating from orogenic gold deposits. Formation occurs during late stage mountain building (''see [[orogeny]]'') where metamorphism forces gold containing fluids into joints and fractures where they precipitate. These tend to be strongly correlated with quartz veins.<ref name="Jenkin-2014" />
* [[Epithermal vein deposit]]s form in the shallow crust from concentration of metal bearing fluids into veins and stockworks where conditions favour precipitation.<ref name="Pirajno-1992" /><ref name="Mosier-2012" /> These volcanic related deposits are a source of gold and silver ore, the primary precipitants.<ref name="Mosier-2012" />

=== Sedimentary deposits ===

[[File:MichiganBIF.jpg|thumb|Magnified view of banded iron formation specimen from Upper Michigan. Scale bar is 5.0 mm.]]
[[Laterite]]s form from the weathering of highly mafic rock near the equator. They can form in as little as one million years and are a source of [[iron]] (Fe), [[manganese]] (Mn), and [[aluminum]] (Al).<ref name="Persons-1970" /> They may also be a source of nickel and cobalt when the parent rock is enriched in these elements.<ref>{{Cite journal |last1=Marsh |first1=Erin E. |last2=Anderson |first2=Eric D. |last3=Gray |first3=Floyd |date=2013 |title=Nickel-cobalt laterites: a deposit model |journal=Scientific Investigations Report |page=59 |doi=10.3133/sir20105070h |issn=2328-0328|doi-access=free |bibcode=2013usgs.rept...59M }}</ref>

[[Banded iron formation]]s (BIFs) are the highest concentration of any single metal available.<ref name="Jenkin-2014" /> They are composed of chert beds alternating between high and low iron concentrations.<ref>{{Cite journal |last=Cloud |first=Preston |date=1973 |title=Paleoecological Significance of the Banded Iron-Formation |url=http://pubs.geoscienceworld.org/economicgeology/article/68/7/1135/18462/Paleoecological-Significance-of-the-Banded |journal=Economic Geology |language=en |volume=68 |issue=7 |pages=1135–1143 |doi=10.2113/gsecongeo.68.7.1135 |bibcode=1973EcGeo..68.1135C |issn=1554-0774}}</ref> Their deposition occurred early in Earth's history when the atmospheric composition was significantly different from today. Iron rich water is thought to have upwelled where it oxidized to Fe (III) in the presence of early photosynthetic plankton producing oxygen. This iron then precipitated out and deposited on the ocean floor. The banding is thought to be a result of changing plankton population.<ref name="cloud-1968">{{cite journal |last1=Cloud |first1=Preston E. |year=1968 |title=Atmospheric and Hydrospheric Evolution on the Primitive Earth. |journal=Science |volume=160 |pages=729–736 |bibcode=1968Sci...160..729C |doi=10.1126/science.160.3829.729 |jstor=1724303 |pmid=5646415 |number=3829}}</ref><ref>{{Cite journal |last1=Schad |first1=Manuel |last2=Byrne |first2=James M. |last3=ThomasArrigo |first3=Laurel K. |last4=Kretzschmar |first4=Ruben |last5=Konhauser |first5=Kurt O. |last6=Kappler |first6=Andreas |date=2022 |title=Microbial Fe cycling in a simulated Precambrian ocean environment: Implications for secondary mineral (trans)formation and deposition during BIF genesis |url=https://linkinghub.elsevier.com/retrieve/pii/S0016703722002514 |journal=Geochimica et Cosmochimica Acta |language=en |volume=331 |pages=165–191 |doi=10.1016/j.gca.2022.05.016|bibcode=2022GeCoA.331..165S |s2cid=248977303 }}</ref>

Sediment Hosted Copper forms from the precipitation of a copper rich oxidized brine into sedimentary rocks. These are a source of copper primarily in the form of copper-sulfide minerals.<ref name="Sillit20172">{{cite journal | doi=10.1007/s00126-017-0769-x | title=Reply to discussions of "Age of the Zambian Copperbelt" by Hitzman and Broughton and Muchez et al | year=2017 | last1=Sillitoe | first1=Richard H. | last2=Perelló | first2=José | last3=Creaser | first3=Robert A. | last4=Wilton | first4=John | last5=Wilson | first5=Alan J. | last6=Dawborn | first6=Toby | journal=Mineralium Deposita | volume=52 | issue=8 | pages=1277–1281 | bibcode=2017MinDe..52.1277S | s2cid=134709798 }}</ref><ref>{{Citation |last1=Hitzman |first1=Murray |title=The Sediment-Hosted Stratiform Copper Ore System |date=2005 |url=https://pubs.geoscienceworld.org/books/book/1940/chapter/107716228 |work=One Hundredth Anniversary Volume |access-date=2023-03-05 |publisher=Society of Economic Geologists |language=en |doi=10.5382/av100.19 |isbn=978-1-887483-01-8 |last2=Kirkham |first2=Rodney |last3=Broughton |first3=David |last4=Thorson |first4=Jon |last5=Selley |first5=David}}</ref>

[[Placer deposit|Placer]] deposits are the result of weathering, transport, and subsequent concentration of a valuable mineral via water or wind. They are typically sources of gold (Au), [[platinum group]] elements (PGE), [[sulfide mineral]]s, tin (Sn), [[tungsten]] (W), and [[rare-earth element]]s (REEs). A placer deposit is considered alluvial if formed via river, colluvial if by gravity, and eluvial when close to their parent rock.<ref name="Best-2015" /><ref name="Haldar-2013" />

=== Manganese nodules ===
[[Polymetallic nodules]], also called manganese nodules, are mineral [[concretion]]s on the [[sea]] floor formed of concentric layers of [[iron]] and [[manganese]] [[hydroxide]]s around a core.<ref>{{Cite journal |last=Huang |first=Laiming |date=2022-09-01 |title=Pedogenic ferromanganese nodules and their impacts on nutrient cycles and heavy metal sequestration |url=https://www.sciencedirect.com/science/article/pii/S0012825222002318 |journal=Earth-Science Reviews |volume=232 |pages=104147 |doi=10.1016/j.earscirev.2022.104147 |bibcode=2022ESRv..23204147H |issn=0012-8252}}</ref> They are formed by a combination of [[Diagenesis|diagenetic]] and sedimentary precipitation at the estimated rate of about a centimeter over several million years.<ref>{{Cite journal |last1=Kobayashi |first1=Takayuki |last2=Nagai |first2=Hisao |last3=Kobayashi |first3=Koichi |date=October 2000 |title=Concentration profiles of 10Be in large manganese crusts |url=https://linkinghub.elsevier.com/retrieve/pii/S0168583X00002068 |journal=Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms |language=en |volume=172 |issue=1–4 |pages=579–582 |doi=10.1016/S0168-583X(00)00206-8}}</ref> The average diameter of a polymetallic nodule is between 3 and 10&nbsp;cm (1 and 4 in) in diameter and are characterized by enrichment in iron, manganese, [[heavy metals]], and [[rare earth element]] content when compared to the Earth's crust and surrounding sediment. The proposed mining of these nodules via [[Remotely operated underwater vehicle|remotely operated]] ocean floor trawling robots has raised a number of ecological concerns.<ref>{{Cite news |last=Neate |first=Rupert |date=2022-04-29 |title='Deep-sea gold rush' for rare metals could cause irreversible harm |language=en-GB |work=The Guardian |url=https://www.theguardian.com/environment/2022/apr/29/deep-sea-gold-rush-rare-metals-environmental-harm |access-date=2023-11-28 |issn=0261-3077}}</ref>