Digital re-evaluation of down-dip channel-fill architecture in deep-water slope deposits: Multi-scale perspectives from UAV-SfM

Abstract

Recent advances in sea floor measurements and modelling have revealed new insight into submarine channel processes; however, understanding how these short-term perspectives influence long-term evolution of submarine channels has been limited by the difficulty in linking processes to products in the stratigraphic record. Outcrops present opportunities to characterise the detailed internal architecture of deep-water channel fills over a wide range of timescales, but obtaining observations is compounded by challenges in outcrop accessibility and perspective along broad exposures. To demonstrate the potential value of modern remote sensing techniques in supplementing fieldwork, an extensive dip-oriented outcrop exposure of Cretaceous deep-water channel deposits was re-evaluated using a 3D digital outcrop model generated from uninhabited/unmanned aerial vehicle photogrammetry. Results confirmed previous field-based documentation of depositional element-scale stratigraphic architecture, but also revealed nuanced internal detail that was not captured from field-based perspectives alone. Subtle internal channel-fill architecture, including discontinuous sandstone wedges and the interpreted stratigraphic products of upslope-migrating bedforms, are also recognised. This study demonstrates the sedimentary detail that can be uncovered by integrating conventional field-based approaches limited by viewable scale, perspective, and/or accessibility, with emerging remote sensing techniques. The unmanned aerial vehicle photogrammetry approach used here provides valuable supplemental data in the investigation of deep-water channel system deposits and has the potential to overcome inherent challenges in outcrop mapping for numerous applications.