Digital re‐evaluation of down‐dip channel‐fill architecture in deep‐water slope deposits: Multi‐scale perspectives from UAV‐SfM. (1st March 2021)

• Record Type: Journal Article
• Authors: Nesbit, Paul R.; Hubbard, Stephen M.; Daniels, Benjamin G.; Bell, Daniel; Englert, Rebecca G.; Hugenholtz, Christopher H.
• Is Part Of: Depositional record. Volume 7:Number 3(2021)
• Page Start: 480
• Page End: 499
• Publication Date: 2021-03-01
• Subjects: channel architecture -- deep‐water slope deposits -- SfM photogrammetry -- stratigraphic architecture -- UAV -- upslope‐migrating bedforms; Sediments (Geology) -- Periodicals; Sedimentology -- Periodicals; Sedimentation and deposition -- Periodicals; 552.5
• DOI: 10.1002/dep2.137
• Languages: English
• ISSNs: 2055-4877

Abstract

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. Abstract : Outcrops provide opportunities to characterise sedimentological detail within depositional systems across geologic timescales, but outcrop geometry and accessibility may not always allow for complete characterisation. Emerging remote sensing techniques, such as UAV‐SfM, can supplement field‐studies with additional perspectives and reveal nuanced detail that is imperceptible in the field. We present a case study in which UAV‐SfM mapping methods confirm and enhance previous field‐based documentation of broad‐scale stratigraphic architecture in deep‐water channel deposits, but also reveal subtle internal details (including the deposits from upslope‐migrating bedforms) that were largely overlooked using a conventional field‐based approach and have implications that complement recent work in modern deep‐water depositional settings.