PROVENANCE AND SYNTECTONIC DEPOSITIONAL HISTORY OF THE MIOCENE CAMERINO DEEPWATER BASIN, CENTRAL ITALY

The Miocene deepwater clastic basins in the central Apennines of Italy serve as timekeepers of orogenic processes related to compressional tectonics and foredeep basin development. Although the general stratigraphic framework of these basins is well-established, the precise provenance history and details of the tectonically controlled sedimentary routing systems linking the hypothesized Alpine source areas to their sedimentary sinks remain ambiguous. The Camerino Basin (CB) is a small structurally confined turbidite basin in this system positioned between two larger depocenters; the Marnosa-Arenacea Basin (MAB) to the west and the Laga Basin (LB) to the east and provides an opportunity to evaluate the relative sedimentary contribution of Alpine source material and intrabasin recycling.

Here we present preliminary data from an integrated geochemical-petrographic-stratigraphic approach that combines: a multiproxy geochemical approach using laser ablation inductively coupled plasma- mass spectrometry (ICP-MS) and electron microprobe analysis (EPMA) of heavy minerals, with particular focus on garnets, rutile, zircon, and apatites; U-Pb radiometric dating of detrital zircon and apatites; petrographic analysis of thin sections; and bedrock geologic mapping and stratigraphic analysis in the field.

Mapping and stratigraphic and petrographic analysis reveals the presence of a large ~2km wide vertically stacked turbidite channel complex filled with predominately coarse grained sandstones composed of abundant metamorphic rock fragments (MRFs) and metamorphic minerals in the CB sandstones suggesting that the bulk of the sediment in the CB was derived from an Alpine source. Preliminary geochronological data from processed CB samples show two major zircon ²³⁸U/²⁰⁶Pb age populations centered at 277.5 Ma and 37.5 Ma, confirming previously documented ages from nearby basins. Apatites however, show an U-Pb age of ~22 Ma is that is not represented in the zircon data indicating the contribution of different provenance sources. These results show the utility of using a multi-mineral approach to constrain provenance history and the full depositional record relating more precisely the syntectonic clastic basins of the Apennines with their Alpine source rocks.