STUDY OF PHYSICAL AND CHEMICAL-PROPERTIES OF VITRINITES - INFERENCES ON DEPOSITIONAL AND COALIFICATION CONTROLS

A detailed study of petrological, geochemical, textural and coking pro perties was carried out on vitrains from the Puertollano, Blanzy-Montc eau, Asturias and Teruel. The objective was to determine in depth the physical and chemical properties of a series of natural and pure vitri nites of different rank, and the influence that the sedimentary and po st-sedimentary conditions had on them. It is demonstrated that althoug h vitrains are almost entirely made up of the huminite/vitrinite macer al group they have a different composition, thermal behaviour and phys ical properties. Thus, geochemical and textural properties of Blanzy-M ontceau vitrains can be considered to be representative of the telinit e, the major component in both samples (75% vol.) at the beginning of the bituminization stage (subbituminous/high volatile C bituminous coa ls). The characteristics of the Puertollano vitrains described here ca n also be attributed to the telocollinite (> 80% vol.) for the high vo latile C bituminous coal. Variations in physico-chemical properties be tween Puertollano and Blanzy-Montceau vitrains are due to the differen ces in the initial composition of organic matter. Slight differences ( i.e., bed moisture content or porosity) between vitrains from the two coal seams in the same basin can be attributed to their stratigraphic position. Several parameters such as S-2, HI, oil and extraction yield and fluorescent properties suggest that the Puertollano and Blanzy-Mo ntceau vitrains have a lower hydrocarbon potential. The relationships between geochemical and textural properties make it possible to distin guish between 'normal' and perhydrous vitrains. The two different hydr ogen-enrichment processes that occur in vitrains from the Teruel and A sturias basins can be distinguished from the extraction yield data. (C ) 1998 Elsevier Science B.V. All rights reserved.