Estudio y clasificación de la materia orgánica dispersa (MOD) en el Lías de la Playa de Peñarrubia (Asturias)

Abstract

A study of the organic matter of a marine sequence of the west part from Peñarrubia Beach (Asturias) has been carried out using pyrolysis tests and petrographic and geochemical techniques. White light and fluorescence microscopic observations have permitted to establish a general classification of the disperse organic matter, its distribution and concentration along the series, and also the variation with the litology. The organic components have been classified into nine groups which are mainly found in the Upper part of the Pliensbachian marlaceous and lutitic beds. These bituminous leveis are composed of a kerogen type 11 or mixed, with a small contribution of terrestrial humic materials. The rank of DOM has been determined by huminite reflectance and Rock-Eval (Tmax), being both results concordant. The DOM is in an inmature stage before the oil generation window. The highest oil yields determined by pyrolysis tests at 500°C correspond to the richest DOM levels. Petrographic and geochemical data show a good correlation. AIgae, fibers, organic-mineral matrix and other submicroscopic associations are the main source for oil generation.