Mediterranean turbidite systems are deposited adjacent and within developing orogens and there has been an increasingly recognition of the role of active structures within basins and their influences on facies distribution. Some turbidites basins such Marnoso-Arenacea in northern Italy, regarded to have been deposited in tectonically quiescent settings are now seen as influenced by advancing thrust fronts of the orogeny. Here we show outcrops examples on how active basin floor can control the facies distribution on a turbidite basin. This study case comes from the Nebrodi and Madonie Mountains (northern of Sicily), a region that contains the greatest expanse of Numidian strata (Oligocene- Miocene) in the central Mediterranean. The system was controlled by thrust related folds and their intrabasin submarine slopes, together with basin floor architecture inherited from the under-filled passive continental margin. We also demonstrate that deforming basin-floor can be revealed by entrainment of substrate into the sand-fairways. Thrust-top basins filled diachronously implying a large scale tectonic control both on sand fairways and facies variations along their margins. Existing models wrongly suggest that facies variations between adjacent outcrops on Sicily (and elsewhere) result from long-range stratigraphic variations being juxtaposed by later large-displacement thrusts. Our research challenge this ideas and propose a much simpler tectonic structure but a more complex stratigraphic arrangement for the Numidian on Sicily. We outline the evidence for this deduction and develop the consequences for understanding of the Maghrebian orogenic system that has deformed this margin during the Neogene.

Why is the Numidian a confined turbidite system?

MANISCALCO, ROSANNA
2016

Abstract

Mediterranean turbidite systems are deposited adjacent and within developing orogens and there has been an increasingly recognition of the role of active structures within basins and their influences on facies distribution. Some turbidites basins such Marnoso-Arenacea in northern Italy, regarded to have been deposited in tectonically quiescent settings are now seen as influenced by advancing thrust fronts of the orogeny. Here we show outcrops examples on how active basin floor can control the facies distribution on a turbidite basin. This study case comes from the Nebrodi and Madonie Mountains (northern of Sicily), a region that contains the greatest expanse of Numidian strata (Oligocene- Miocene) in the central Mediterranean. The system was controlled by thrust related folds and their intrabasin submarine slopes, together with basin floor architecture inherited from the under-filled passive continental margin. We also demonstrate that deforming basin-floor can be revealed by entrainment of substrate into the sand-fairways. Thrust-top basins filled diachronously implying a large scale tectonic control both on sand fairways and facies variations along their margins. Existing models wrongly suggest that facies variations between adjacent outcrops on Sicily (and elsewhere) result from long-range stratigraphic variations being juxtaposed by later large-displacement thrusts. Our research challenge this ideas and propose a much simpler tectonic structure but a more complex stratigraphic arrangement for the Numidian on Sicily. We outline the evidence for this deduction and develop the consequences for understanding of the Maghrebian orogenic system that has deformed this margin during the Neogene.
Numidian system; confined turbidites; active basin
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/102959
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