Palaeogeography of the Upper Cretaceous–Eocene carbonate turbidites of the Northern Apennines from provenance studies
Andrea Argnani, Daniela Fontana, Cristina Stefani, Gian G. Zuffa, 2006. "Palaeogeography of the Upper Cretaceous–Eocene carbonate turbidites of the Northern Apennines from provenance studies", Tectonics of the Western Mediterranean and North Africa, G. Moratti, A. Chalouan
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The Upper Cretaceous Helminthoid Flysch (HF) of the Northern Apennines consists of thick and regionally widespread deep-water carbonate turbidite successions, deposited during the initial stages of Alpine collision. The HF spans the time from Turonian to Early Eocene and is mainly composed of intrabasinal carbonate ooze mixed with clay; siliciclastic terrigenous beds are also present, but they are a volumetrically minor component of the successions. Petrographic and sedimentological signatures indicate that the HF was deposited in distinct basins located below the carbonate compensation depth. Bulk composition and heavy minerals of terrigenous beds indicate provenance from different crustal levels of the European and Adria plates. The petrographic and palaeobathymetric characteristics of these turbidites indicate the coexistence of an active-margin tectonic setting, a palaeogeographical position suitable for carbonate ooze production and storage, and limited supply of terrigenous detritus into the basin. Palaeotectonic reconstructions and stratigraphic data suggest that Adria represented a vast repository of penecontemporaneous carbonate mud; the presumably intense seismic activity related to the pre-collisional Alpine orogeny promoted large-scale failures of shelf and/or slope biogenic muddy sediments, resulting in the deposition of a large volume of carbonate turbidites. Only occasionally, turbidity currents probably linked to exceptional fluvial floods generated pure terrigenous beds with different petrographic signatures for each HF succession.
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This book provides an insight into the overall tectonic evolution of the Western Mediterranean region and North Africa. The tectonic setting of the region reflects a long-lived and complex evolution, mainly related to the Alpine Orogeny. This inheritance is expressed by an intricate pattern of arc-shaped mountain chains, the Alps, the Betic–Rif Cordilleras and the Apennine–Maghrebian belt, whose southern branches mark the present limit between the African and Eurasian plates. The volume covers the Maghrebian chains in North Africa, from Tunisia to Morocco and the Western and Central Mediterranean, from Spain to Italy from the pre-orogeric phases (Palaeozoic–Mesozoic) to the post-collisional neotectonic and Quaternary development. It includes both original research papers and syntheses dealing with the aspects of structural, sedimentary, metamorphic and marine geology.