THERMOANALYTICAL DEHYDROXYLATION OF CLAYS AND COMBUSTION OF ORGANIC-COMPOUNDS IN A PROGRADE METAMORPHIC LIASSIC BLACK SHALE FORMATION, CENTRAL SWISS ALPS

Thermoanalytical investigations (thermoanalysis combined with the anal ysis of the evolved gases) have been carried out on bituminous claysto ne samples from Switzerland with different diagenetic and metamorphic grades, ranging up to lower amphibolite facies. Mainly the course of w ater loss and the combustion of the organic compounds in flowing air w ere examined by thermoanalytical heating. The highest temperature of t he structure water release from the samples was assigned to the dehydr oxylation of the smectitic/illitic clays and muscovitic as well as par agonitic layer silicates, and is shown to be dependent on diagenetic a nd metamorphic grade. The highest temperature of combustion of the org anic substance in the claystone samples is a good indication for the g rade of diagenesis and metamorphism. The increase of the highest tempe ratures of dehydroxylation and combustion of the organic compounds sho ws a similar trend as the delta(13)C isotopic ratio of the organic com pounds with increasing degree of metamorphism.