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 WebThis graphic illustrates the process by which we think banded iron formations formed. In the early earth there was hot spring deposits driven by volcanic activity, causing circulation of sea water through the ocean crust. And as that sea water moved through the ocean crust it dissolved some of the minerals in the crust and became enriched in ...

Iron-rich sedimentary rocks - Wikipedia

WebMar 3, 2015 · BIF is a sedimentary rock with stripes of iron and silica which is well known to geologists and rock collectors. While it is generally accepted that BIF formed when dissolved iron oxidised and... WebAbout Banded iron formation Hide. Commonly termed BIFs by geologists, they are iron-rich rocks almost always of Precambrian age, predominantly associated with the great oxygenation event (GOE) about 2.3-2.8 billion years ago. It typically consists of repeated, thin iron oxide layers (a few mm to a few cm in thickness) but may be banded from a ... sid symposium digest of technical papers 影响因子

Banded iron formation - Simple English Wikipedia, the free …

WebBanded Iron Formation. Most of the major iron deposits worldwide occur in rocks called banded iron formations (or BIFs for short), which are finely layered sedimentary rocks … WebDec 13, 2024 · Banded iron formations (BIFs) comprise the largest iron resource on Earth. They formed throughout much of the Precambrian (∼3,800–543 Ma), reaching their maximum abundance between 2,700 and 2,400 Ma ago. Numerous examples can be found on almost every continent. WebThe Precambrian banded iron formations are, therefore, suggested to have been formed in a lacustrine or closed-basin environment. Known limnological processes are invoked to provide a mechanism for the common rhythmic banding of iron and silica. The difference between the dominantly nondetrital, low-alumina, banded Early-Middle Precambrian and ... the portland anxiety clinic