Characterization of blocks within a near seafloor Neogene MTC, Orange Basin: Constraints from a high-resolution 3D seismic data

Paschal Ogechukwu Amaechi, Nicolas David Waldmann, Yizhaq Makovsky, Mimonitu Opuwari

Research output: Contribution to journalArticlepeer-review


Submarine mass wasting processes in deepwater settings can incorporate large blocks, which may play a key role in deepwater geological processes and geohazard assessment. However, there is a limited understanding of the deformation style arising from the interaction between submarine blocks and structural/bathymetric barriers such as ramps. The deformation and kinematic history of several submarine blocks (with a thickness of up to 150 m) within a near seafloor mass transport complex in the Orange Basin are documented using seismic geomorphic methods. The interpreted blocks are preserved in three discrete fault-bounded morphological terrains within a Neogene mass-transport complex. These terrains vary in lengths from 2 km to 6 km; they have heights of 60 m to 150 m and are characterized by discrete and localized structural highs on the present-day seafloor. Block sizes vary across terrains suggesting differences in the block evolution process. Blocks near the ramp appear in seismic profiles comprising (a) Chaotic and transparent seismic reflections and (b) parallel to sub-parallel, continuous, low to moderate amplitude reflections. This variability in seismic facies of the blocks reflects the degree of their interaction and translation over a ramp at the basal shear zone of the mass transport complex, evidenced by the difference in the block features on the upslope portion of the ramp versus the downslope part. Notably, the deformation styles recorded in the blocks show the impact of the ramp during mass flow, which has broader implications for understanding the internal mechanisms of blocky mass transport complexes in many continental margins.

Original languageEnglish
Article number106319
JournalSedimentary Geology
StatePublished - Feb 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.


  • Deepwater
  • MTC
  • Orange Basin
  • Seismic
  • Submarine blocks

ASJC Scopus subject areas

  • Geology
  • Stratigraphy


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