The Ombrina-Rospo Plateau (Apulian Platform): Evolution of a Carbonate Platform and its Margins during the Jurassic and Cretaceous

Abstract

In this paper we analyze the Jurassic and Cretaceous evolution of the buried northwards stretch of the Apulia Platform (Southern Italy) (Ombrina-Rospo Plateau – ORP), and adjacent Adriatic Basin. Exploration wells indicate that inner platform carbonate facies across the ORP in the Jurassic and Lower Cretaceous are capped, along a subaerial exposure surface, by Oligocene/Miocene carbonates. A NW-trending intra-platform basin (“Casalbordino Corridor”) was infilled with shallow- to deeper-water sediments in the late Early to Late Cretaceous interval, while platform margins were experiencing tectonic reactivation.The ORP-to-basin transitional belt formed a corner, defining a NW and a NE margin. The NW margin was essentially stationary. A syn- and early post-rift platform-toe bypass wedge formed when late Hettangian–Sinemurian extension produced the platform/basin relief. Export of platform material, coupled with a halt of faulting, made the platform/slope profile continuous in the late Early or early Middle Jurassic (possibly across an ooidal rim). Late Jurassic Ellipsactinia/coral reefs passed downdip into bioclastics. The Maiolica Fm. displays two cycles (M1, M2), where M2 onlaps the slope built by M1. In the Aptian, with lithospheric arching, a high angle fault rejuvenated the margin. Off this margin, a narrow basin, locked between the ORP and a pelagic carbonate platform, was largely infilled with turbidites sourced by the ORP, but the high hampered the dispersal of the sand fraction. The NE margin displays prograding ooidal to bioclastic clinoforms (Middle and Upper Jurassic) downlapping onto the rift basin. In the Lower Cretaceous, the platform recovered after a slow-down of carbonate productivity (M1/2 boundary). The Marne a Fucoidi Fm. thickens at the toe of, and seals, a fault backstepping the margin. Further backstepping occurred ∼5 km platformwards along a (Cenomanian?) normal fault, producing room for a rudist factory. A retreating rocky shoreline sourced breccias, while downdip the shallow water facies graded into the Scaglia Fm. basin along a ramp-like profile with low angle clinoforms, merging with turbidites.