The thermal history of the Baltic Basin evaluated by means of a multidisciplinary approach, the IMPr– Integrated Maturity Profile

Grigo D., Aldega L., Andreucci B., Caricchi C., Corrado S., Di Paolo L., Romano C., Zattin M. (2014)
Orale (Grigo), 87° Congresso della Società Geologica Italiana, 10-12, settembre, Milano
Rend. Online Soc. Geol. It., Suppl. n. 1 al Vol. 31

ABSTRACT

The definition of the thermal history of a sedimentary basin in the oil industry is classically made collecting vitrinite reflectance data and calibrating them with a PSM tool on the basis of some geologically reliable postulations. Sometimes the experimental data are not able to describe a homogeneous maturity profile for lack of data reliability or for absence of vitrinite macerals. So the maturity profile results quite discontinuous for the lack of shaly sequences or cloudy for the lack of good vitrinite fragments. This will increase the uncertainties on the maturity evaluation. The usage of additional parameters based on FT-IR and Raman spectroscopic analysis, both on dispersed organic in addition to X-ray diffraction on fine grained sedimentary rocks will help in reducing the uncertainties of the maturity profiles. In any case vitrinite reflectance does not help in defining the timing of heating processes and sometimes the geological postulations risk to link to an infinite number of combinations affecting again the uncertainty of the model. The usage of thermochronological techniques (fission-tracks and U-Th/He analysis, both on apatite) can help in
reducing those uncertainties for two main reasons. First of all they permit to fill the gap in the maturity profile because they cover the terrigenous part of the sequence usually scarce of not reworked vitrinite fragments. Moreover they can also reduce the uncertainties in the definition of the timing of heating processes because they permit to fix some important time points in the thermal history of the basin. The application of all these techniques to the Polish Baltic basin permitted to develop some important issues in the thermal history evolution of the eastern margin of the Russian craton. In particular a Meso-Cenozoic heating event can be postulated and will help in explaining the differences that exist between the present thermal regime and the maturity trend.