Abstract
Erosion of the seafloor is often interpreted to be the result of turbidity currents and reflects their frictional and non-cohesive nature. However, evidence of the interaction between sediment gravity-flows and the substrate forming the sea floor has been increasingly reported in the literature. Based on styles of basal interaction with the substrate, we here propose a broad classification of submarine mass movements labelled free- and no-slip flows. Three mechanisms are proposed for free-slip flows during translation of mass movements that are effectively detached from the substrate; hydroplaning, shear wetting, and substrate liquefaction. In contrast, no-slip flows occur where the mass movement is welded to the substrate, and the strain front lies within the substrate itself. In the latter case, flows can erode by pushing forward and/or ploughing into the substrate, often remobilizing sediments that are later incorporated into the flow, a common characteristic shared by many mass transport deposits (MTDs) containing blocks. Additionally, linear track features (e.g. grooves and striations) are described as a consequence of substrate tooling by rigid blocks. Using outcrops in NW Argentina as a detailed case study, we have recorded evidence for penetration of the strain profile into sediments underlying MTDs and categorised the deformation into no-slip basal deformation that may display continuous and discontinuous profiles. Continuous deformation profiles involve the complete deformation of the uppermost layers of the substrate, while discontinuous deformation profiles preserve a undeformed substrate layer between the MTD and the zone of deformed substrate. These features highlight the erosive and deformational nature of MTDs, and can be used as potential kinematic indicators.
Original language | English |
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Pages (from-to) | 629-639 |
Number of pages | 11 |
Journal | Marine and Petroleum Geology |
Volume | 98 |
Early online date | 24 Aug 2018 |
DOIs | |
Publication status | Published - Dec 2018 |
Bibliographical note
We acknowledge the support of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) - Brazil, Shell and the University of Aberdeen. The authors would like to thank GCSSEPM and SEPM for permission to publish some of their published figures and to all authors whose works were cited here as case studies.We would like to thank the following colleagues for their support, camaraderie and countless hours of fieldwork: Claus Fallgatter, Victoria Valdez, Carla Puigdomenech, Guilherme Bozetti, Roberto Noll Filho, Arthur Lemos Giovannini, Qun Liu, Thisiane dos Santos, Pan Li, Amanda Santa Catarina, Ramon Lopez Jimenez and Larissa Hansen. Last but not least, we thank Lorena Moscardelli and Kei Ogata for their insightful reviews that improved this manuscriptKeywords
- mass-transport deposits
- substrate deformation
- substrate erosion
- liquefaction
- hydroplaning
- no-slip flows
- free-slip flows