Stratigraphic and structural features of the Bas Ostriconi Unit (Corsica): Palaeogeographic implications

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• 作者：Luca Pandolfi^a ; ^c ; ^{pandolfi@dst.unipi.it} ; Michele Marroni^a ; ^c ; Alessandro Malasoma^b
• 关键词：Alpine Corsica ; Stratigraphy ; Deformation history ; Bas Ostriconi Unit ; Narbinco Flysch ; Ligure-Piemontese basin
• 刊名：Comptes Rendus Geoscience
• 出版年：2016
• 出版时间：November-December 2016
• 年：2016
• 卷：348
• 期：8
• 页码：630-640
• 全文大小：6458 K
• 卷排序：348

文摘

The palaeogeographic origin of the Bas Ostriconi Unit (Balagne area, Alpine Corsica) has long been a matter of debate. This unit is actually detached from its original basement. It is made of Late Cretaceous carbonatic turbidites with lenses of coarse-grained polymict conglomerates (Narbinco Flysch). The turbidites have a mixed siliciclastic-carbonatic composition and are affected by a polyphasic deformation. Here, based on field observations and sampling, we analyse the sedimentary, petrographic, and structural features of the Narbinco Flysch. From these analyses, we derive that the Narbinco Flysch belongs to the sedimentary cover of the Balagne ophiolite Nappe. We also show that the carbonatic turbidites are associated with mixed siliciclastic-carbonatic coarse-grained debris, which is typical of the turbidite sediments deposited during the Late Cretaceous in the Ligure-Piemontese oceanic basin close to the European Margin. Our results thus suggest that, the Bas Ostriconi Unit succession originally formed on the Ligure-Piemontese oceanic crust, then was integrated to the accretionary wedge that was thrusted on the European margin of Corsica during the Eocene collisional events.