Wyoming-type montmorillonites

It is considered likely that the catalytic Na-rich, Wyoming-type montmorillonites are distinctive not because of the composition of the original volcanic ash, but rather due to the saline-rich waters into which the volcanic ash was deposited and subsequently altered during shallow burial. 

Although uncertainty remains, the environments required for the formation of Wyoming-type montmorillonites (i.e., explosive eruptions of volcanic ash granitic compositions deposition of volcanic ash into saline water shallow burial) may conceivably have been present on the prebiotic Earth. Formation of RNA oligomers would have proceeded fi-om activated monomers if the aqueous environment had a pH in the neutral to mildly basic range (40). 

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