Question

HELP??
Banded iron formations were caused by the production of which atmospheric gas?

Answer 1

The conventional concept is that the banded iron layers were formed in sea water as the result of oxygen released by photosynthetic cyanobacteria. The oxygen then combined with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the ocean floor, which may have been anoxic mud (forming shale and chert). Each band is similar to a varve, to the extent that the banding is assumed to result from cyclic variations in available oxygen.

It is unclear whether these banded ironstone formations were seasonal, followed some feedback oscillation in the ocean's complex system or followed some other cycle.[8]

It is assumed that initially the Earth started with vast amounts of iron and nickel dissolved in the world's acidic seas. As photosynthetic organisms generated oxygen, the available iron in the Earth's oceans precipitated out as iron oxides.

At a suspected tipping point where the oceans became permanently oxygenated, small variations in oxygen production produced periods of free oxygen in the surface waters, alternating with periods of iron oxide deposition.

Snowball Earth scenario[edit]

Answer 2

Okay, lol thank you.