AboutKeith Patton Expertise I can answer questions concerning physical and historical geology, environmental geology/hydrology, environmental consulting, remote sensing/aerial photo interpretation, G&G computer applications, petroleum exploration, drilling, geochemistry, geochemical and microbiological prospecting, 3D reservoir modeling, computer mapping and drilling.I am not a geophysicist.
Experience I have 24 years experience split between the petroleum and environmental industries. I have served as an expert witness in remote sensing, developmental geologist, exploration geologist, enviromental project manager, and subject matter expert in geology and geophysical software development.
Organizations American Association of Petroleum Geologists
American Association of Photogrammetrists and Remote Sensing
Education/Credentials Bachelor and Master of Science
Registered Geologist in State of Texas
Question QUESTION: how banded iron formation formation was occured? and what was the process?
also i want to know why we don't find any clastic material in that formation? also i want to know is that such process also occuring anywhere on the earth ocean?
ANSWER: Ankush:
These formations formed during the Precambrian and are attributed to the combination of oxygen with iron in the early formation of the Earths oceans.
They are said to contain 20 times the oxygen presently in our atmosphere bonded with the iron in the oxidized state.
The process was the combination by oxidation of oxygen released by the photosynthetic action of blue green algae with dissolved iron in the sea water. The iron oxide precipitated out to form the thin layers.
These are very similar to clay varves found in some lake sediments forming a record of a cyclic process.
Some are tying the formation of these deposits to the Snow Ball Earth hypothesis. Which would make it similar in some ways to the formation of varves, representing the result of freeze thaw cycles and depletion followed by enrichment of the ocean waters with oxygen in a cyclic manner.
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QUESTION: sir i want to know that why these formation are baneded with quartzite only? if such kind of oxygen was there then from where this much amount of iron is coming and why they form alternate layer with ouartzite mainly? if there was so much iron there then why it stops precipitating and then after some time again start forming?
Answer The reason they are interbedded with quartz, usually jasper or other microcrystalline quartz is that silica was added to the ocean water at mid ocean spreading centers and was precipitated out in alternating bands with the iron. The iron was being contributed from terrestrial sources as well as additional continental quartz sediments that would explain conglomeritic and quartzite deposits seen in some areas. The cyclic nature of the iron precipitation depends on the availability of oxygen, which would become depleted halting the precipitation, then ocean thawing would occur (as proposed by the snow ball earth hypothesis) resulting in oxygenation of the ocean again then refreezing resulting in more precipitation.
