Sedimentary analysis of the deep-water (Pliocene) Pellini Member, Corinth Rift, Greece
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This sedimentological study focuses on the architectural elements distinguished within the deep-water Pellini Member. The Pellini Member is located south of the active Corinth rift, within the uplifted and incised Pliocene-Pleistocene rift basin of the northern Peloponnese Peninsula, Greece. This syn-rift succession is exposed in a small area along the western side of the northeast oriented Sythas valley, 7 km south of the Xylocastro village. The coarse-grained Pellini member belongs to the turbiditic/hemipelagic Rethio-Dendro Formation, Lower Group. The northeast dipping Amphithea fault separates the Pellini Member from the relatively younger parts of the Rethio- Dendro Formation. The identification of the palaeoenvironmental and palaeogeographic depositional setting, and mechanisms controlling the evolution of the Pellini Member was achieved by integrating traditional fieldwork techniques with LiDAR-based digital outcrop modelling, combined with literary research. This combination allowed the identification of 11 architectural elements, distinguished as channelized and non-channelized elements. Channelized elements are described as Large-scale complex sheets (AE1), Large-scale complex ribbons (AE2), Large-scale complex U-shaped elements (AE3), Large-scale simple ribbons (AE4), Small-scale simple U-shaped elements (AE5), Small-scale simple ribbons, (AE6), and Small-scale simple ribbon-sheets (AE7). Non-channelized elements are described as Deformed large-scale complex sheets (AE8), Thin-to thick- bedded sandstone sheets (AE9), Sandy heterolithics (AE10), and Mudstone with thin-bedded sandstone sheets (AE11). These architectural elements represent meandering (AE1, 2 and 4), non-meandering (AE3), and crevassing channels and splays (AE5, 6, and 7), alternating with interchannel deposits (AE8, 9, 10, and 11). The orientation, geometry and stratigraphic distribution of the large- and small-scale channelized elements, points towards a branched channel system. This system is dominated by sinuous distributives and crevassing channels, alternating with interchannel deposits. Multi-storey channels comprise vertically and/or laterally stacked channel bodies which indicate their planform development to have been controlled by the degree of aggradation, avulsion and lateral confinement. Laterally stacked channels indicate modest lateral confinement and a relatively low rate of overbank aggradation. Vertically stacked channels reflect lateral confinement and/or high rates of sediment aggradation. Meandering single-storey channels are unilateral, indicating a low degree of lateral confinement, combined with relatively low rates of aggradation. Crevassing channels and splays exhibits the highest variations in planform geometry; rapidly changing in thickness and width in the transition from being confined to unconfined. The sedimentary system reflects relatively high rates of sediment aggradation overall, combined with high rates of channel avulsion and bifurcation, which are the main processes controlling the channels' planform development and the creation of thickening and thinning upwards sandstone sheets. High rates of aggradation are caused by the high frequency of coarse-grained turbidity flows, which is the main transport mechanism of sediments to the deep-water fan-channel system. Despite...
PublisherUniversitetet i Bergen (UiB)
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