A STRATIGRAPHIC AND TECTONOFACIES FRAMEWORK OF THE CALCARI-A-LUCINA IN THE APENNINE CHAIN, ITALY

The Apennine Chain provides the first example of stratigraphic (time) and synsedimentary tectonic (space) distribution of the ''calcari a Lu cina'' Miocene equivalents of modern cold-vent carbonates. Chemosynthe tic faunal assemblages and related carbonate deposits are found at dif ferent stratigraphic levels, with peaks during Langhian-Serravallian a nd late Tortonian-early Messinian times. A general increase in frequen cy and volume occurs with time. A ''genetic link'' between venting and the Messinian Evaporite event is difficult to demonstrate. However, L ucina limestones are limited to preevaporitic times, and their maximum abundance is reached just before the onset of the Messinian Evaporite accumulation. Lucina limestones occur in almost all tectofacies of th e orogen, from backland to foreland.