Castiglione (Oletta, Corsica): relationships between phenomena of calcification and tectonic fossiliferous fracture dating

Six cavities have been discovered in the Oletta massif. The massif, today c onstitued of Schistes lustres with several metres of calcareous layers abov e them, has undergone intense fracturing. The networks of cavities are orga nised along north-south and subequatorial directions, and form a narrow bay onnet-network. All the elements in the galleries appear to be karstic: stal agmites, stalactites and calcitic deposits along the walls; but no trace of dissolution or excavation was found. Thus, the origin of the galleries is only tectonic, while the calcitic deposits result from the dissolution of t he old, thick calcareous layers above, which are no longer present. The thi ckness and the volume of the calcitic deposits, which is variable depending on the galleries, indicates the chronology of the different tectonic perio ds which have fractured the massif. Five tectonic and successsive events ha ve been detected. Calcitic datings confirm the timing of successional fract uring, indicating also the variable age of the fossiliferous Middle Pleisto cene deposits found in these cavities. (C) 1999 Editions scientifiques et m edicales Elsevier SAS.