Geomorfologia sísmica de feições deposicionais e erosionais do sistema deltaico Eridanos (Plioceno do Setor Holandês do Mar do Norte).

Abstract

Depositional and erosional features along two specific surfaces within Pliocene strata of the Dutch sector of the North Sea were studied based on using seismic geomorphology and seismic stratigraphy concepts. This study consisted of the interpretation of a high quality 3D seismic cube (~ 400 km²) acquired in shallow water (~ 40 m), which covers the Eridanos fluvio-deltaic depositional system. The free software OpendTect was used to analyze two key stratigraphic surfaces. Some seismic attributes and filters were used to highlight palaeogeomorphological features on the selected horizon slices. The first one, a maximum flooding surface, shows a network of tributary channels incised onto the slope and merging into larger, probably hyperpycnal channels developed on the basin floor. Local evidence of contour currents was also identified. The second horizon, a subaerial unconformity, presents evidence of widespread action of contour currents and local action of turbidity currents partially reworking the contourites. The results enhanced the close relationship between extreme climate conditions (glacial and interglacial) and erosional / depositional geomorphological features (e.g. contour currents scours and depositional streaks, tributary drainage network and associated submarine channels, and turbidite channels and lobes).