Histological and franboidal textures in diagenetic Pyrite from the Gondwana coal beds, Brazil

Pyrite occurs in the Gondwana coal measures of the Tubarao Group, in the Parana sedimentary basin, Southern Brazil. Polished sections of pyrite from the Carnbui area show framboidal and histological textures which are interpreted as evidence for the syngenetic origin of the pyrite, deposited during diagenesis. Subordinate marcasite, which occurs as secondary veins and concentric bands with colloform textures, would indicate formation in a locally acid environment. The anatomical structures observed in polished sections of pyrite show parts of a complex vascular system which suggests that current opinion concerning the affinities of the forms of the Southern Hemisphere with those of the Northern Hemisphere should be revised.