Precambrian banded iron-formations of the Ijil Group (Kediat Ijil, Reguibat Shield, Mauritania)

Bronner, Georges; Chauvel, Jean-Jacques

doi:10.2113/gsecongeo.74.1.77

Cited by 34 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2.25 to 2.10 Ga Lomagundi carbon isotope excursion in South Africa (Silverton Formation;Schweigart, 1965) and on the Kola Peninsula in Russia (Kuetsjärvi Sedimentary Formation; Akhmedov, 1972a). The IFs deposited during the Lomagundi excursion include those within the Ijil Group, Mauritania (Bronner and Chauvel, 1979) and the Lomagundi Group, Zimbabwe (Master, 1991). The former belongs to the 2.20-2.10 Ga Birimian Basin in West Africa, which also contains iron and manganese formations in the Francevillian Basin, Gabon (Leclerc and Weber, 1980) and in the Nigerian schist belts (Mücke, 2005).…”

Section: Minor Iron Formation Deposition After the Goe And Before Camentioning

confidence: 99%

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

Konhauser

Planavsky

Hardisty

et al. 2017

Earth-Science Reviews

382

257

View full text Add to dashboard Cite

Section: Minor Iron Formation Deposition After the Goe And Before Camentioning

confidence: 99%

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

Konhauser

Planavsky

Hardisty

et al. 2017

Earth-Science Reviews

382

257

View full text Add to dashboard Cite

“…The BIFs deposited during the Lomagundi excursion include those in the Ijil Group, Mauritania (Bronner and Chauvel, 1979) and the Lomagundi Group, Zimbabwe (Master, 1991). The former belongs to the 2.2 to 2.1 Ga Birimian basin in West Africa that also contains Algoma-type iron and manganese formations in the Francevillian basin, Gabon (Leclerc and Weber, 1980) and in the Nigerian schist belts (Mücke, 2005).…”

Section: Iron Formations Deposited After the Goe And Before Ca 193 Gamentioning

confidence: 99%

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

Bekker¹,

Krapež²,

Slack³

et al. 2010

Economic Geology

854

494

View full text Add to dashboard Cite

Iron formations are economically important sedimentary rocks that are most common in Precambrian sedimentary successions. Although many aspects of their origin remain unresolved, it is widely accepted that secular changes in the style of their deposition are linked to environmental and geochemical evolution of Earth. Two types of Precambrian iron formations have been recognized with respect to their depositional setting. Algoma-type iron formations are interlayered with or stratigraphically linked to submarine-emplaced volcanic rocks in greenstone belts and, in some cases, with volcanogenic massive sulfide (VMS) deposits. In contrast, larger Superior-type iron formations are developed in passive-margin sedimentary rock successions and generally lack direct relationships with volcanic rocks. The early distinction made between these two iron-formation types, although mimimized by later studies, remains a valid first approximation. Texturally, iron formations were also divided into two groups. Banded iron formation (BIF) is dominant in Archean to earliest Paleoproterozoic successions, whereas granular iron formation (GIF) is much more common in Paleoproterozoic successions. Secular changes in the style of iron-formation deposition, identified more than 20 years ago, have been linked to diverse environmental changes. Geochronologic studies emphasize the episodic nature of the deposition of giant iron formations, as they are coeval with, and genetically linked to, time periods when large igneous provinces (LIPs) were emplaced. Superior-type iron formation first appeared at ca. 2.6 Ga, when construction of large continents changed the heat flux at the core-mantle boundary. From ca. 2.6 to ca. 2.4 Ga, global mafic magmatism culminated in the deposition of giant Superior-type BIF in South Africa, Australia, Brazil, Russia, and Ukraine. The younger BIFs in this age range were deposited during the early stage of a shift from reducing to oxidizing conditions in the ocean-atmosphere system. Counterintuitively, enhanced magmatism at 2.50 to 2.45 Ga may have triggered atmospheric oxidation. After the rise of atmospheric oxygen during the GOE at ca. 2.4 Ga, GIF became abundant in the rock record, compared to the predominance of BIF prior to the Great Oxidation Event (GOE). Iron formations generally disappeared at ca. 1.85 Ga, reappearing at the end of the Neoproterozoic, again tied to periods of intense magmatic activity and also, in this case, to global glaciations, the so-called Snowball Earth events. By the Phanerozoic, marine iron deposition was restricted to local areas of closed to semiclosed basins, where volcanic and hydrothermal activity was extensive (e.g., backarc basins), with ironstones additionally being linked to periods of intense magmatic activity and ocean anoxia.Late Paleoproterozoic iron formations and Paleozoic ironstones were deposited at the redoxcline where biological and nonbiological oxidation occurred. In contrast, older iron formations were deposited in anoxic oceans, where ferrous iron oxid...

show abstract

“…Most economic BIF is of Archean and Paleoproterozoic age (James 1983;Hofmann 2005;Alexander et al 2008;Johnson et al 2008;Bekker et al 2010), although some deposits occur in younger terranes of Neoproterozoic age following a hiatus of over a billion years from *1800 to *800 Ma (e.g., Pelleter et al 2006, Ali et al 2010, Basta et al 2011Stern et al 2013;Khalil et al 2015). In North Africa, significant BIF deposits occur in Egypt and more importantly in Mauritania where the largest deposits are documented (Bronner and Chauvel 1979;Taylor et al this volume) (Figs. 9 and 10).…”

Section: Bif Depositsmentioning

confidence: 99%

“…All of these rocks underlie the northeastern portion of the western Reguibat Shield. In contrast, the allochthonous Paleoproterozoic sequences of the Kediat Ijil Complex, which overlies the Tiris Complex, consist of metamorphosed (low grade) magnetite-rich chert and barren clastic sedimentary rocks including conglomerate, sandstone, and mica schist with subordinate carbonates and very few volcanic rocks (Bronner and Chauvel 1979). Although not directly dated radiometrically, geological constraints suggest that the Ijil Complex is Paleoproterozoic (Taylor et al this volume) and that the contained iron formations (i.e., Kediat Ijil and Guelb El Mhaoudat deposits) are Superior-type BIF that was deposited on the northeastern passive margin of the Archean Rgueibat Shield.…”

Section: Bif Depositsmentioning

confidence: 99%

“…These time periods coincide with major increased rates of crustal growth and subsequent supercontinent formation and breakup, all of which are associated with mantle plumes and the development of Archean-Paleoproterozoic cratons (e.g., Groves et al 2005). Major and well-documented examples include in Mauritania the Guelb Moghrein IOCG deposit Kolb et al 2008;Kirschbaum 2011;Kolb and Petrov 2015;Kirschbaum and Hitzman 2016) and associated Mesoarchean to Paleoproterozoic BIFs (Bronner and Chauvel 1979;Taylor et al this volume), the numerous Birimian orogenic and intrusion-related gold deposits of Mali (McFarlane et al 2011;Lawrence et al 2013a, b, Salvi et al 2015Markwitz et al 2015;Masurel et al 2015Masurel et al , 2016Lawrence et al this volume), and the Tasiast orogenic goldfield of Mauritania (Heron et al 2015).…”

Section: 16mentioning

confidence: 99%

See 1 more Smart Citation

Geologic and Metallogenic Framework of North Africa

Bouabdellah

Slack

2016

Mineral Deposits of North Africa

View full text Add to dashboard Cite

North Africa is noteworthy for having a great diversity of geology and mineral resources. Geologically, the region contains numerous terranes that contain rocks ranging in age from Archean to Quaternary, including diverse igneous, sedimentary, and metamorphic lithologies. Major geological features were built during the main phases of Proterozoic and subsequent Phanerozoic orogenies, the break-up of the supercontinents Rodinia, Gondwana, and Pangea, and during the opening and closing of major ocean basins such as the Iapatus, Atlantic, Pacific, and Tethys. Three major tectono-stratigraphic domains are recognized (1) the Precambrian province that includes the African-Nubian Shield (ANS) to the east and the West African Craton (WAC) to the west, and the intervening Tuareg Shield and "Saharan Metacraton"; (2) the Variscan (Paleozoic) fold belt; and (3) the Atlas-Alpine (Mesozoic-Cenozoic) system. Mineral deposits of North Africa formed in a variety of geologic settings at different time periods from Archean to Quaternary. Mineral commodities including gold, silver, cobalt, nickel, chromium, arsenic, copper, lead, zinc, iron, and many other elements. Major deposit types present in the region are (1) orthomagmatic Cr-Ni-platinum group elements (PGE); (2) rare-metal granites and related rare-element pegmatites; (3) volcanic-hosted massive sulphide (VHMS); (4) sedimentaryexhalative (SEDEX); (5) orogenic and intrusion-related gold; (6) iron oxide-copper-gold (IOCG); (7) banded iron formation (BIF); (8) Mississippi Valley-type (MVT) lead-zinc; (9) sediment-hosted stratiform copper;Electronic supplementary material The online version of this chapter

show abstract

Precambrian banded iron-formations of the Ijil Group (Kediat Ijil, Reguibat Shield, Mauritania)

Cited by 34 publications

References 0 publications

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

Geologic and Metallogenic Framework of North Africa

Contact Info

Product

Resources

About