WebBanded iron formation (BIF) is a lithological term applied to a thinly bedded or laminated chemical sedimentary rock consisting of successive layers of fine-grained quartz, iron oxides, carbonates, and/or silicates, typically containing 20–40% of iron and 40–50% of silica (Trendall 2002; Klein 2005 ). Overview WebThis banded iron formation comes from a rock unit 60 meters thick that formed over a 50-million-year period, from 2.736 to 2.687 billion years ago. The red bands are silica-rich, composed primarily of jasper, and the black bands contain the iron oxide mineral magnetite.
Banded Iron Formations Encyclopedia.com
WebThis oxygen immediately combined with the abundant dissolved iron to produce hematite or magnetite. These minerals deposited on the sea floor in great abundance, forming what … WebMay 12, 2024 · Banded iron formations typically have alternating layers: FIRST LAYER: The first layer is either magnetite (Fe 3 O 4 ) or hematite (Fe 2 O 3 ) a few millimeters to a … shanghai journal of economics缩写
Banded iron formation - Wikipedia
WebMay 21, 2024 · banded iron formation (BIF) Finely banded, siliceous, hematite deposits found in Precambrian rocks, forming stratiform units often several hundred metres thick and persistent over 150 km or more. They probably formed by chemical—organic processes during sedimentation in stable, shallow basins with little detritus, and so are syngenetic … WebThere are two major types of deposit. The first, and by far the most important, is banded iron formations (BIFs), so called because they are finely layered alternations of cherty silica and an iron mineral, generally … Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness and extend laterally for several hundred kilometers. Almost all of … See more A typical banded iron formation consists of repeated, thin layers (a few millimeters to a few centimeters in thickness) of silver to black iron oxides, either magnetite (Fe3O4) or hematite (Fe2O3), alternating with bands of iron … See more Banded iron formations provide most of the iron ore presently mined. More than 60% of global iron reserves are in the form of banded iron formation, most of which can be found in … See more • Iron-rich sedimentary rocks – Sedimentary rocks containing 15 wt.% or more iron • Stromatolite – Layered sedimentary structure formed by the growth of bacteria or algae See more Banded iron formations are almost exclusively Precambrian in age, with most deposits dating to the late Archean (2800-2500 Ma) with a … See more Banded iron formation provided some of the first evidence for the timing of the Great Oxidation Event, 2,400 Ma. With his 1968 paper on the early atmosphere and oceans of the earth, Preston Cloud established the general framework that has been widely, if … See more • Harnmeijer, J.P. (2003). "Banded Iron Formation: A Continuing Enigma of Geology". University of Washington. Archived from the original on 8 September 2006. See more • Media related to Banded iron formation at Wikimedia Commons • Banded-iron formation at the Encyclopædia Britannica • "Jaspilite" . Encyclopedia Americana. 1920. See more shanghai jps medical co. ltd