Influence of MTD-related relief on the stratigraphic architecture of subsequent gravity-flow and current-controlled deposits
Presented by Dr. Lorena MOSCARDELLI on 23 Sep 2013 from 17:15 to 19:15
Type: Poster presentation
Session: Poster session
Significant seabed relief can develop along the upper surface of mass transport deposits (MTDs). However, the style of accommodation associated with MTD-related seabed relief and the way in which it influences the evolution and distribution of subsequent gravity-driven (e.g. turbidites) and current-controlled (e.g. contourites) deposits is relatively unknown and scarcely documented. This work seeks to address the fundamental questions associated with the influence that MTDs have on slope morphology, accommodation and depositional patterns in overlying units. Seismic reflection data from the Gulf of Mexico (Lobster area) and offshore Brazil (Santos Basin) are used to illustrate how complex MTD surface topography varies in deep-water environments. The Gulf of Mexico (GoM) data showcases a detached-MTD that locally developed on the flank of a salt body; a series of rotational slides were generated within this MTD and multiple, low-relief depocentres originated on its upper surface. Younger strata onlap the top surface clearly indicating that the underlying MTD formed significant seabed relief that influenced subsequent depositional patterns. In contrast, the Santos Basin seismic data showcases a regionally-developed attached-MTD that contains kilometer scale megablocks that have been transported from the slope onto the distal basinfloor. These megablocks generated seabed relief that modified the average gradient of the MTD upper surface, thus generating additional accommodation and constraining the location of localized depocenters. The relationships illustrated by these subsurface examples are also observed in outcrops in the Paganzo Basin (northwest Argentina), Ablation Point Formation (Antarctica) and Sierra Contreras (Chile), as well as in the subsurface of the UK North Sea using core correlations. It is clear that MTD-related seabed relief can control accommodation development in deep-water settings, and our work is part of an ongoing attempt to better document this influence and integrate data from the subsurface and outcrops. This study is relevant for oil and gas exploration activities because it can help us improve our capacity to predict areas where reservoir prone intervals (e.g. turbidites) can preferentially accumulate in deep-water settings.
Location: GEOMAR East shore
Address: Wischhofstr. 1-3 / D-24148 Kiel