Sedimentary processes on the west Hellenic Arc margin

Abstract

SUM M ARY: High-resolution seismic surveys across the western Hellenic Arc show that the Plio-Quaternary cover is highly discontinuous along most of the margin. The slope displays a series of basins separated by ridges generally devoid of sediment. Sedimentological analyses of the recent sediment permit the origin and processes of sedimentation to be defined. The sediments provided by a specific area on land are successively trapped, released by the slope basins and transferred via channels and canyons towards the deeper trench basins. Several main provinces can be distinguished. Each of them includes one or more slope basins and trenches without either lateral connection or the mixing of sediment inputs. The diversity and complexity of sedimentary structures, the granulometric characters, and the variability in rates of sedimentation argue for the prevalence of mass gravity processes. The transfer of sediment from the upper slope basins to the outer trench is effected by an alternation of short periods of giant mudflows and regular but slight reworking between slope basins. This cascade-feeding process, characteristic of the Hellenic subduction margin, does not appear to prevent terrigenous material from reaching the deep trenches. We compare this briefly with sedimentation on passive margins in the western Mediterranean Basin.

Sediment fluxes and the evolution of a riverine-supplied tectonically-active coastal system: Kyparissiakos Gulf, Ionian Sea (eastern Mediterranean)

“…slides, debris flows, turbidites); these are often triggered by earthquake shocks (Ferentinos 1992), associated with the subduction zone. Such gravitational mass movements are common along the flanks of the Hellenic Trench system and have also been reported for the region of the dextral transformation, the Kefallonia Fault (to the north of Kyparissiakos Gulf) (Ferentinos 1992;Poulos et al 1999) and to the south of the study area (Got et al 1981;Got 1984).…”

Turbidites and iron formations, Beardmore‐Geraldton, Ontario: application of a combined ramp/fan model to Archaean clastic and chemical sedimentation

“…Another cause of slumping could be seismic shocks, which are thought to be important in causing resedimentation on active margins (cf. Got, 1984). In this regard, the occurrence of bundles of thin graded sands (Fig.…”

Ιζηματολογικη Και Γεωχημικη Μελετη Των Ιζηματων Της Ηπειρωτικης Κρηπιδας Του Κυπαρισσιακου Κολπου

“…Ελάχιστες επικεντρώνουν το ενδιαφέρον τους στην λιθοστρωματογραφία των νεογενών και τεταρτογενών σχηματισμών. Δύο μελέτες των Hageman (1977) και Καμπέρη (1987) Οι Vittori (1978), Vittori et al (1981), Got (1984), Got et al (1981) (Vittori, 1978;Le Quellec et al, 1980;Got, 1984) (Got, 1984). (Stanley & Maldonado, 1981) Οι Vittori (1978), Vittori et al (1981), Got et al (1981) Πριν αρχίσει η κύρια κοκκομετρική ανάλυση των δειγμάτων πραγματοποιήθηκε απομάκρυνση των οργανικών με Η 2 0 2 και των ανθρακικών με HCl (Galehouse, 1971).…”