The iron in these strata originally arrived via the erosion of iron-bearing silicate minerals. Initially, this iron accumulated as iron-oxide coatings, which formed slowly after the sand had been deposited. Later, after having been deeply buried, reducing fluids composed of water and hydrocarbons flowed through the thick red sand which once comprised the Navajo Sandstone. The dissolution of the iron coatings by the reducing fluids bleached large volumes of the Navajo Sandstone a brilliant white. Reducing fluids transported the iron in solution until they mixed with oxidizing groundwater. Where the oxidizing and reducing fluids mixed, the iron precipitated within the Navajo Sandstone. Depending on local variations within the permeability, porosity, fracturing, and other inherent rock properties of the sandstone, varying mixtures of hematite, goethite, and limonite precipitated within spaces between quartz grains
I wanted to check sources before I answered some of the questions I asked. The main weakness I see with this hypothesis is that the hematite "precipitated" up through sandstone. This is a faulty premise which defies chemistry, and fluid mechanics.
Hematite is ferric
iron (FeO+++), and is not water soluable. It turns the water reddish brown--it's rust basically. Hematite and water are a reversible colloid
This is opposed to ferrous iron (FeO++), which is water soluable, and completely dissoves in water. The result is that FeO++ does not dye the water--it will remain clear, because it is completely dissolved. http://www.idph.stat...eets/ironFS.htm"Iron is mainly present in water in two forms: either the soluble ferrous iron or the insoluble ferric iron. Water containing ferrous iron is clear and colorless because the iron is completely dissolved. When exposed to air in the pressure tank or atmosphere, the water turns cloudy and a reddish brown substance begins to form. This sediment is the oxidized or ferric form of iron that will not dissolve in water."http://www.idph.stat...eets/ironFS.htm
The argument is then strong against upward "precipitation" of FeO+++ into the sands and sandstones. The hematite in the water, which is what caused it to turn reddish brown, would have been a colloid. The "rust" and the water would have been seperate similar to oil and water, only the rust is a heavy metal, and solid. The heavier hematite, in standing water, precipitates downward, not upward. This is how conventional geology believes the banded iron formations were formed--a settling of FeO+++ on a lake or sea bed."The conventional concept is that the banded iron layers were formed in sea water as the result of oxygen released by photosynthetic cyanobacteria (bluegreen algae), combining with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the substrate, which may have been anoxic mud...." http://en.wikipedia....rmation#Origins
In order for an emulsion or colloid to be blended there has to be aggitation of the mixture, just like vinagrette salad dressing. If you leave it set, it will again seperate. How do you propose aggitation of water and hematite under highly compacted and pressurized sands. So one could say that the concept of upward "precipitation" of already existing hematite in groundwater below the sands would defy gravity and chemistry. It is falsified by the principles stated above.
However, a moving water current can suspend rust, just as our drinking water does in old water systems, where it has had time to form. The fact that water and FeOlll are a reversible colloid predicts that standing water, unlike moving water current which suspends the rust, will cause a downward precipitation of the rust to a bottom surface. It will remain there unless sufficiently aggitated. Unless the hypothesizer can provide a realistic mechanism whereby the rust/ water mixture were aggitated in the highly pressurized sands and sandstones, the hypothesis, which is seriously accepted science, contrarily has no scientific footing at all.
If the hypothesis of millions of years and that the hematite went downward initially were true, a more realistic result is that it would have stained the underneath materials. But to think that it went up through rock, to make a rather even staining on such large areas in the southwest doesn't work.