light reading

heres a little piece i put together myself from research gathered from many different sources, its as accurate as currently theorized but please DYOR. I hope its of interest and a good read, for this part I've just gone over banded iron formation if its well received I'll write again on CID&DID.
Pretty hard to condense 4500000000years of evolution
The epic story of iron ore…
It was originally assumed that due to the majority of fossils found that life on earth dated back some ware between 530-550mill years, this was considered to be the Cambrian. However as the fossils disappeared further into the past the Precambrian was born and indeed covered over two thirds of the planets age, so because the Cambrian has no impact on our story we shall go way back to the early Precambrian. Even this is broken into Eons, Eras, Periods, Epochs and Ages, so we shall just deal with the three Eons that split up the Precambrian and evolved the planet to what we have now including our magnificent iron formations!
We’ll begin at the very beginning in the first eon the Priscoan (4.6-3.9 bill years ago) these were turbulent times for the young solar system, the sun and planets all having just formed from a huge cloud of star dust left over from up to four huge chemical building suns that had gone supernova long ago. To help our story, the last elements a star builds before its spectacular demise are iron and nickel, there are more lighter built before and heavier built in the supernova itself but again we’re only dealing with iron so lets get on with the brand new proto planet sitting 90mill miles from its star. At this stage we’re not the fourth rock but one of many cause at about 4bill years ago another planetoid about the size of Mars hit us and the impact ripped the planet apart then when everything had settled we had our moon! If life had started prier to this an ELE (extinction level event) of this magnitude would have seen a back step, however we are now in the Archean eon (3.9-2.5 bill years) and the planet has started cooling and forming geological features. Far from the planet we know and love, the atmosphere is a toxic mix of nitrogen and carbon dioxide and the boiling oceans are sulphuric acid about the Ph of battery acid. This is when life begins; enter Cyanobacteria (photosynthetic blue green algae), still around today in various forms including as a symbiont in plants known commonly as chloroplast (the green stuff). Cyanobacteria was one of the first photosynthesizes, using sun light and feeding on hydrogen and carbon ions to produce energy, this process released oxygen as a waste product.
Now we come to iron, as you know the earth is a ball of rock and iron, but iron being heavy gravitated to the liquid mantle to be brought to the surface with other elements by volcanoes. A good deal of these volcanoes lay under water and the heavy metals including iron remained diluted in solution in the anoxic oceans, however iron oxide isn’t soluble and as the Cyanobactiria released oxygen it oxidized the iron causing it to fall out of solution and drop to the ocean floor. For some unknown reason this process was periodic as no layer is more than 10cm thick.
Between these layers of predominately hematite and magnetite are layers of chert (clear quartz with crystals of submicroscopic size), jasper (impure opaque silica, usually of red colour) and shale (fine grained sedimentary rock-clay minerals as mud, most common sedimentary rock), oh and blue asbestos. The end result are BIF, banded iron formations which to be classed as BIF must contain 15% iron. Geological processes have continued and as such every continent has BIF as part of their landscapes, however only the most ancient lands (cratons) have the most preserved formations.
All this happened during the early Archean through to the Proterozoic (2.5-.55 bill years, most of the Precambrien) then stopped once oxygen levels on the planet had stabilized, not the end of Cyanobacteria however probably the most prolific polluter the world has ever see, dragging carbon dioxide out of the atmosphere putting oxygen in but plunging the world into several ice ages! This is the life they’ll find on Mars, has been here long before us and nodoubt long after we’re gone.
Please note CID (channel iron deposits) and DID (detrital iron deposits) are secondary processes caused by erosion and various other geological activity however BIF because of their biochemical nature are classed as fossils and are amongst the worlds oldest fossils and oldest forms of sedimentary rock!
..................Flaming.........:)