The relationship between three parameters, the Tmax given by Rock-Eval pyrolysis, the illite content in illite-smectite mixed layers (I-S) and the Kübler Index (KI) has been investigated in the Cretaceous–Neogene, sedimentary syn-orogenic successions in the Northern Apennines (Italy). A strong relationship was found between maturity stages of kerogen, illite content in I-S and KI. The oil formation zone for continental organic matter (Type III), delimited by Tmax between 434 and 465°C, corresponded to rocks with short-range ordering R1, I-S with illite content between 60 and 85% and KI values in the range 0.85–0.65 (°Δ2θ). Over-mature rocks were characterized by Tmax >465°C, a long-range ordered I-S with an illite content >85% and KI in the range 0.65–0.45 (°Δ2θ). The relationship permits use of both mineralogical parameters and Tmax to estimate palaeotemperatures in sedimentary successions and it can be exploited in hydrocarbon research to evaluate the petroleum potential.

You do not currently have access to this article.