EVALUATING THE DETRITAL RECORD OF APENNINE OROGENESIS USING MULTI-PROXY PROVENANCE METHODS IN THE MARNOSO-ARENACEA AND LAGA BASINS, NORTHERN AND CENTRAL APENNINES, ITALY

Foreland basin deposits in northern and central Italy formed adjacent to the actively deforming Apennine Mountain chain in response to subduction and collision between the Adriatic and African plates. Geodynamic models of the Apennine foreland basin invoke both slab rollback and slab detachment as potential drivers of basin formation but during different phases. These processes have resulted in discrete depozones that migrated perpendicular to the orogenic front during the Early Miocene, and along-strike during Middle Miocene–Pliocene time, which resulted in the deposition of the Marnoso-arenacea (MAF) and Laga formations that span this geodynamic transition. One model suggests that basin development was dominated by frontal accretion driven by slab rollback processes leading to trench-ward migration of foredeeps with sedimentation derived primary from the central and southern Alps. Another view suggests that basin migration was driven by a combination of slab rollback and slab detachment processes. In this model, early basin formation was driven by frontal accretion followed by along-strike foredeep migration during slab detachment with sedimentation derived from the uplifting Apennine clastic wedge.

We present new raman detrital heavy mineral and detrital garnet geochemical datasets from these stratigraphic intervals. Samples from the MAF include, in stratigraphic order, the Langhian, Serravallian (Units I-VI), and Tortonian strata (Castel del Rio and Fontanelice turbidite mixed systems). In the Laga basin, sampled stratigraphic intervals include the Messinian Laga 1b, Laga 2, and Laga 3 successions. These new datasets from this study are used in concert with existing U-Pb detrital zircon and detrital apatite fission track datasets to asses upsection and spatial variations from mafic and high-pressure source terranes that are often not examined in in the detrital stratigraphic record.