AGE VARIATION IN THE SOURCE OF THE DIAPIRIC MUD BRECCIA ALONG AND ACROSS THE AXIS OF THE MEDITERRANEAN RIDGE ACCRETIONARY COMPLEX

Pleistocene, or younger, mud diapirism is recorded along the arcuated crest of the Mediterranean Ridge Accretionary Complex over a distance of more than 450 km. The extruded mud-supported breccia, named mud bre ccia, is poorly fossiliferous, but the matrix may be dated as Late Apt ian to Albian and Late Burdigalian to Langhian in age based on the cal careous plankton content. Calcareous nannofossils and planktonic foram inifera diagnostic of other ages are sparse within the two above-menti oned major assemblages. They indicate the presence of sediments attrib utable (1) to the Santonian and Cenomanian which occur in association with the mid-Cretaceous assemblages (Toronto, Unnamed, and Aros Domes) , and (2) to the Serravallian which occur in association with the Late Burdigalian-Langhian assemblages in the Gelendzhik Dome. Aptian-Albia n to Late Cretaceous sediments are pelagic in origin and are similar t o the Scisti a Fucoidi and Scaglia Rossa Formations well known from co ntinental Italy. Mixed,dolomitic clasts and crystals also occur within the matrix, indicating the presence of portions of the evaporitic seq uence of Messinian age in four cores from the western locations. Singl e, very rare plankton specimens, indicative of other ages different fr om those mentioned above, also occur within the matrix at various plac es. They are interpreted as reworked primarily within the Late Burdiga lian-Langhian sediments. The age of the emplacement of the breccia sho uld be older than the Middle Pleistocene as supported by the occurrenc e of clasts of this age in the mud breccia and is still an ongoing pro cess at least in the Napoli Dome.