Interaction of deepwater sandstones with the substrate: analogues from Numidian turbidites (Miocene) of Sicily

Deepwater quartz-rich sandstones derived from mature cratons form reservoirs in many hydrocarbon provinces. These include not only rifted margins of the Atlantic but also tectonically active margins where turbidity currents have interacted with deformed substrate. An understanding of the controls on the distribution of sandstone body thickness and architecture will aid exploration and production strategies in these areas. The Numidian “flysch” is an Oligo-Miocene succession of clean, quartz-rich deep marine sandy turbidite deposits sourced from the North African craton and transported northwards across the continental margin into the foredeep system of the Apennine orogen. The regional extent of these sands is well-established; they extend for some 500 km along strike and down dip with outcrops preserved within the Maghrebian-Apennine thrust belt of Sicily and southern Italy. These deposits are commonly regarded to have been deposited on undeformed substrate within ancentral foredeep, however there are evidences that the turbidity flows interact with active basin evidenced by large scale onlap and relationship between basin floor and slope substrata. This work focuses on detailed mapping of the Numidian stratigraphy and establishing the chronostratigraphic and structural relationships to underlying and overlying stratigraphic units in order to constrain local and regional basin architecture. Key stratigraphic sections were logged and palaeocurrent data collected to establish sand fairways across Sicily. Also eleven sandstone samples were analyzed by LA-ICPMS and show detrital zircon ages strongly consistent with African source signature. Biostratigraphic samples (foraminifera) were collected to establish chronostratigraphic context and correlation between the sections. Panoramic views were traced to follow lateral continuity and geometry of the beds. Future work will focus on extending the study across northern and Central Sicily to better constrain the influence of basin tectonics on ponding and deflection of the Numidian gravity flows.