Answers are grounded in this paper and cite their sources.
Ferric illite (Fe‐illite) developed extensively in a siliciclastic submarine fan sequence within a lime‐mud succession in the Proterozoic Penganga Group at Adilabad, South India. The minerals formed as de novo by preferentially replacing high‐K minerals like alkali feldspar and mica. It is compositionally intermediate between glauconite and illite in a continuously varying chemical spectrum. The mineral exhibits an R1 or R3 type stacking sequence, with low (<10%) interlayering of illite and smectite (I/S). All the analyzed grains are characterized by high potash content, and it has been inferred that the maturity is dictated by high ak in the microenvironment. This occurrence strongly calls into question the environmental significance that has so far been attributed to glauconitic minerals.
No takes yet. Share an insight, caveat, or question.
Deb et al. (1998) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: