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- W2099572573 abstract "Almost all economic manganese ores are ultimately or directly derived from hydrothermal vents associated with intermediate volcanic rocks. This source is in contrast to deep-sea nodules, which likely have a larger component of sediment-derived manganese and whose volcanic sources are more mafic. Manganese deposits can be divided into sedimentary rock-hosted, volcanic rock-hosted and karst-hosted, in order of predominance. Two genetic types of sedimentary rock-hosted deposits can also be identified: those with Mn derived via upwelling from oxygen-minimum zones and those formed on the margins of euxinic basins. Most of the large tonnage deposits appear to form by the euxinic mechanism. Manganese ores, like those of Fe, show a strong concentration of deposits in the Paleoproterozoic and a lesser occurrence in the Neoproterozoic, but, unlike Fe, there is an additional strong peak in the Oligocene. Therefore, Mn is not controlled entirely by the level of oxygen in the Earth’s atmosphere. At each peak of Mn deposition, the associated ore deposits are concentrated in a few districts, suggesting a more local than global control on manganese metallogenesis. Age trends can, however, be discerned in some chemical properties of manganese deposits. Overall, there is a trend to progressive increases in chemical diversity from the Archean to the Recent, with a particularly steep increase in the Neoproterozoic-Early Cambrian, corresponding in time to the radiation of metazoans. Also beginning in the Cambrian is the development of upwelling-linked deposits. There is another sharp increase in chemical diversity at the Jurassic-Cretaceous boundary, which includes increased SiO 2 /Al 2 O 3 ratios and corresponds to the radiation of diatoms. There is a conspicuous gap in sedimentary rock-hosted Mn deposits between 1800 and 800 Ma that may correspond to a monotonous, low-oxygen ocean, but one without sulfidic deep water. Alternatively, Mn may have been precipitated entirely in the deep ocean, beneath a sulfidic oxygen minimum layer. The positive Eu anomalies, which in iron formations are equated to vent-sourced metals, are not seen in most Mn deposits, although they are found in Mn-rich iron formations. By contrast, Fe deposits interbedded with major Mn ores lack the usual Eu signal. Therefore, mechanisms of transport between hydrothermal vents and the sites of deposition differed for Fe and for Mn deposits in the Archean-Paleoproterozoic. The dominant pattern in the time trend of Mn deposition is increasing chemical diversity, which reflects an increasing compartmentalization of the Earth’s depositional environments. This compartmentalization was a response to, but also provided a spur to, the diversification of life forms." @default.
- W2099572573 created "2016-06-24" @default.
- W2099572573 creator A5002611084 @default.
- W2099572573 date "2010-05-01" @default.
- W2099572573 modified "2023-10-06" @default.
- W2099572573 title "The Chemistry of Manganese Ores through Time: A Signal of Increasing Diversity of Earth-Surface Environments" @default.
- W2099572573 cites W1510232411 @default.
- W2099572573 cites W1525476360 @default.
- W2099572573 cites W168614109 @default.
- W2099572573 cites W1964033040 @default.
- W2099572573 cites W1964401941 @default.
- W2099572573 cites W1965478052 @default.
- W2099572573 cites W1965536973 @default.
- W2099572573 cites W1967675439 @default.
- W2099572573 cites W1970253591 @default.
- W2099572573 cites W1971098916 @default.
- W2099572573 cites W1971431820 @default.
- W2099572573 cites W1971800909 @default.
- W2099572573 cites W1973000950 @default.
- W2099572573 cites W1973024354 @default.
- W2099572573 cites W1975538373 @default.
- W2099572573 cites W1977018074 @default.
- W2099572573 cites W1978255350 @default.
- W2099572573 cites W1979230725 @default.
- W2099572573 cites W1980131158 @default.
- W2099572573 cites W1980747614 @default.
- W2099572573 cites W1981060637 @default.
- W2099572573 cites W1982626311 @default.
- W2099572573 cites W1986072396 @default.
- W2099572573 cites W1987351790 @default.
- W2099572573 cites W1989662389 @default.
- W2099572573 cites W1990405639 @default.
- W2099572573 cites W1991485769 @default.
- W2099572573 cites W1991724003 @default.
- W2099572573 cites W1994386576 @default.
- W2099572573 cites W1996394922 @default.
- W2099572573 cites W1996917932 @default.
- W2099572573 cites W1997688781 @default.
- W2099572573 cites W1998357168 @default.
- W2099572573 cites W1998669478 @default.
- W2099572573 cites W1999382651 @default.
- W2099572573 cites W2000177754 @default.
- W2099572573 cites W2002769103 @default.
- W2099572573 cites W2003664874 @default.
- W2099572573 cites W2003959525 @default.
- W2099572573 cites W2005887772 @default.
- W2099572573 cites W2010996396 @default.
- W2099572573 cites W2011740723 @default.
- W2099572573 cites W2011801766 @default.
- W2099572573 cites W2014459311 @default.
- W2099572573 cites W2016244971 @default.
- W2099572573 cites W2017344213 @default.
- W2099572573 cites W2017600130 @default.
- W2099572573 cites W2018967433 @default.
- W2099572573 cites W2019197568 @default.
- W2099572573 cites W2019961348 @default.
- W2099572573 cites W2020983353 @default.
- W2099572573 cites W2021986389 @default.
- W2099572573 cites W2023989514 @default.
- W2099572573 cites W2025136132 @default.
- W2099572573 cites W2026254800 @default.
- W2099572573 cites W2027228820 @default.
- W2099572573 cites W2028807360 @default.
- W2099572573 cites W2031678578 @default.
- W2099572573 cites W2031901871 @default.
- W2099572573 cites W2032093895 @default.
- W2099572573 cites W2033301786 @default.
- W2099572573 cites W2036464754 @default.
- W2099572573 cites W2037619434 @default.
- W2099572573 cites W2038756934 @default.
- W2099572573 cites W2039424237 @default.
- W2099572573 cites W2040701129 @default.
- W2099572573 cites W2041762395 @default.
- W2099572573 cites W2042379760 @default.
- W2099572573 cites W2042826964 @default.
- W2099572573 cites W2045543220 @default.
- W2099572573 cites W2046651077 @default.
- W2099572573 cites W2047840445 @default.
- W2099572573 cites W2051553307 @default.
- W2099572573 cites W2051789791 @default.
- W2099572573 cites W2056853496 @default.
- W2099572573 cites W2057100418 @default.
- W2099572573 cites W2057391595 @default.
- W2099572573 cites W2057944078 @default.
- W2099572573 cites W2058058446 @default.
- W2099572573 cites W2059345653 @default.
- W2099572573 cites W2059428275 @default.
- W2099572573 cites W2059828635 @default.
- W2099572573 cites W2060437333 @default.
- W2099572573 cites W2061435088 @default.
- W2099572573 cites W2064576119 @default.
- W2099572573 cites W2064908863 @default.
- W2099572573 cites W2071194416 @default.
- W2099572573 cites W2075613749 @default.
- W2099572573 cites W2079774522 @default.
- W2099572573 cites W2080158106 @default.
- W2099572573 cites W2080891266 @default.
- W2099572573 cites W2081314412 @default.