The thermal diagenesis (catagenesis) of clays has been investigated in samples from the Panarctic et al. North Sabine H-49 well in the Sverdrup Basin in the Canadian Northwest Territories. Upon burial of the sediments, the concentration of expandable 2:1 layer silicate, kaolinite and amorphous inorganic material decreases whereas illite increases in concentration in the clay fractions. The first dehydration of the interstratified clays is made permanent by isomorphic substitution of Si4+ by Al3+ and the ensuing absorption of K+ and coincides with the onset of hydrocarbon generation from the sedimentary organic matter. The clay size fraction also decreases with depth due to destruction of the hydrous clay minerals. Both the destruction of inorganic amorphous material and hydrous clay minerals provides water to the pore system but only the destruction of the latter occurs within the hydrocarbon generation zone. The second dehydration step of the interstratified clays occurs below the oil generation zone. © 1979, Elsevier Science & Technology. All rights reserved.
Foscolos, A. E., & Powell, T. G. (1979). Mineralogical and geochemical transformation of clays during burial-diagenesis (catagenesis): Relation to oil generation. Developments in Sedimentology, 27(C), 261–270. https://doi.org/10.1016/S0070-4571(08)70722-2