Illite crystallinity in the Carboniferous of the Campine-Brabant Basin (Belgium) and its relationship to organic maturity indicators

Abstract

With 4 figures and 2 tables in the text

Relation between graphitization of organic matter and clay mineralogy, Silurian black shales in Central Spain

“…Using the relation given by Cathelineau and Nieva (1985), the temperature of formation was 300 _+ 20 ~ compatible with the mineral assemblages of both types of slates in the area and the anchi-epimetamorphic boundary conditions estimated from the illite crystallinity index. Using the modified equation by Cathelineau (1988), the temperature of formation would be 390 + 20~ too high compared with other independent criteria (Muchez et al, 1991). These results agree with the differences observed between both equations by Hillier and Velde (1991).…”

Late-Variscan fluid migration at the Variscan thrust front of Eastern Belgium: numerical modelling of the palaeothermal and fluid flow field

“…A hydrostatic gradient of 40°C/100bar and a lithostatic gradient of 40°C/ 230bar has been used. A thermal gradient of 40°C km -1 has been modelled in this study and is in agreement with earlier studies Muchez et al 1991). The maximum temperatures obtained are 210 and 270°C, respectively for a hydrostatic and lithostatic gradient.…”

“…The simulated thermal gradients vary slightly because of the various thermal conductivities applied in the model. The modelled geothermal gradient of 40°C km -1 is comparable to the general values in the Variscides deduced from vitrinite reflectance data ) and in northern Belgium (Muchez et al 1991). The all-over temperature enhancement by the high basal heat flow density of 90 mW m -2 does not comprise the peak palaeotemperatures suggested by the chlorite minerals in the Bolland borehole (Zhang et al 1997), nor those deduced from fluid inclusions and organic rank.…”

New findings on the tectono-metamorphic history of the western Rhenish Massif (Germany) by K–Ar dating of metasedimentary illite

“…The parameters influencing the ICI measurements were identified to be of two types: either they depend on the material and/or they relate to sample preparation or equipment settings (e.g. Weaver, 1958;Dunoyer De Segonzac, 1969;Weber, 1972;Buggisch, 1986;Hillier and Clayton, 1989;Kisch, 1990;Muchez et al, 1991;Krumm, 1992). In this study, the values defining the zones of very-low grade metamorphism were set on the basis of sample preparation and used XRD equipment.…”