Séminaire de Riccardo Asti (Géosciences Rennes)


 AHLeGall    27/05/2016 : 21:55

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Le vendredi 27 mai 2016 à 10:30, en salle Bernard Auvray de l'OSUR (campus de Beaulieu, bât.15, RDC), Riccardo Asti propose un séminaire intitulé "Source-to-sink history of a supradetachment basin"

Le vendredi 27 mai 2016 à 10:30, en salle Bernard Auvray de l'OSUR (campus de Beaulieu, bât.15, RDC), Riccardo Asti propose un séminaire intitulé "Source-to-sink history of a supradetachment basin"


Cette présentation est proposée dans le cadre du cycle des séminaires de Géosciences Rennes

Présentation :

Supradetachment basins are common depositional settings associated to the exhumation of continental metamorphic core complexes and with their relatively high sedimentation rates may easily record major tectonic events during their evolution. The Menderes Massif represents the eastern termination of the Aegean Extensional Province and is an outstanding example of Tertiary continental metamorphic core complex, exhumed in the upper Oligocene – Miocene time, during the deposition of a series of E-W trending basins. Several studies address to the exhumation history but the geometry of the depositional system and its evolution are still poorly defined. The aim of this study is to reconstruct the source-to-sink evolution of the Gediz Graben, constraining the activation of the extensional detachment tectonics in the area, defining the exhumation/cooling pattern of the Central Menderes Massif at the footwall of the Gediz Detachment Fault and reconstructing the tectono-stratigraphic evolution of the supradetachment basin. We applied a multidisciplinary approach, mainly consisting in field observations and geological mapping, detrital Apatite Fission Track analyses, in situ U-Th-Pb titanite dating coupled with detailed textural and petrographic analyses, and micropaleontological analyses to constrain the age of sedimentation. Field observation highlighted the main critical points to investigate, as along-strike variations concerting both the margin of the basin and its sedimentary fill; in-situ U-Th-Pb dating on two generation of titanite from the proto-mylonitic Early Miocene Salihli granodiorite and from the mylonitic Gediz Detachment, coupled with careful textural analysis, allowed to constrain the relationship between magmatic emplacement and the activation of the detachment tectonics in the area; a complete detrital Apatite Fission Track study on the samples from both modern river sediments and the from Neogene-to-Quaternary sedimentary succession allowed to constrain the exhumation, erosional and stratigraphic history of the area on long-term and short-term time scales. The proposed evolutionary model for the Gediz Graben highlight the relative role of high angle normal faults vs. low angle detachment faults in the exhumation process, the fundamental role of magmatism in the evolution of this kind of settings and might have major implications on the amount of extension and exhumation accommodated by detachment faults and supradetachment basins in general.

Semin Ricardo Asti 27mai2016


Contact OSUR :
Philippe Steer (Géosciences Rennes)
Benjamin Guillaume (Géosciences Rennes)