Characterization of blocks within a near seafloor Neogene MTC, Orange Basin: Constraints from a high-resolution 3D seismic data
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
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 geo-
morphic 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 de-
gree of their interaction and translation over a ramp at the basal shear zone of the mass transport complex, ev-
idenced 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.
Description
Keywords
Marine science, Geology, Submarine blocks, Orange Basin
Citation
Amaechi, P. O. et al. (2023). Characterization of blocks within a near seafloor Neogene MTC, Orange Basin: Constraints from a high-resolution 3D seismic data. Sedimentary Geology, 444, 106319. https://doi.org/10.1016/j.sedgeo.2022.106319