ANALISI DELL'EVOLUZIONE TETTONICO-SEDIMENTARIA DEI «BACINI MINORI» TORBIDITICI DEL MIOCENE MEDIO-SUPERIORE NELL'APPENNINO UMBRO-MARCHIGIANO E LAZIALE-ABRUZZESE: 3) LE ARENARIE DI M. VICINO, UN MODELLO DI CONOIDE SOTTOMARINA AFFOGATA (MARCHE SETTENTRIONALI)

Abstract

The Monte Vicino Sandstone constitutes a lenticular turbidite body (about 84 Km3 ), about 38 Km in len­ght and 4 Km in width at most, which develops in the NW-SE direction immediately behind the western edge of the Umbro-Marchean Ridge and at the top of the Marnoso-arenacea Formation ("Umbro-Marchean se­quence"). Six lithologic associations have been distin­guished; they correspond to as many turbidite bodies deposited in submarine fan environments: a first type of pelitic-arenaceous (I) which represents basal basin plain and fringe deposits; a first type of arenaceous-pelitic (I) referred to as lower sandy lobe deposits; a second type of pelitic-arenaceous (II) which indicates sediments of the lateral fan fringe; a laminated arenaceous type corresponding to channelized facies; a second type of arenaceous-pe­ litic (II) which indicates upper sandy lo bes; a third type of pelitic-arenaceous (III) referred to as basin plain deposits.