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[[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=":25" /> 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 |doi=10.3133/sir20105070h |issn=2328-0328|doi-access=free }}</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
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=":27" /><ref name=":28" />
=== Manganese nodules ===
[[Polymetallic nodules]], also called manganese nodules, are mineral [[Concretion|concretions]] on the [[sea]] floor formed of concentric layers of [[iron]] and [[manganese]] [[Hydroxide|hydroxides]] 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 |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 |last=Kobayashi |first=Takayuki |last2=Nagai |first2=Hisao |last3=Kobayashi |first3=Koichi |date=2000-10 |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 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>
== Extraction ==
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