Salt-detached strike-slip faulting, Outer Kwanza Basin, Offshore Angola

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1029/2022TC007428. This is version 2 of this Preprint.

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Authors

Aurio Erdi , Christopher Aiden-Lee Jackson 

Abstract

We here use a 3D seismic reflection dataset from Outer Kwanza Basin, offshore Angola to examine the structure and growth of salt-detached strike-slip faults. The faults occur in four, up to 13.8 km-long, NE-trending arrays that are physically linked by restraining bend and releasing stepovers, and which presently overlie Aptian salt and base-salt relief related to pre-salt faulting. We suggest that these faults formed to accommodate along-margin variations in the rate and magnitude of differential seaward translation and salt diapirism, which commenced in the Early Cretaceous. We illustrate that the arrays grew by tip propagation of isolated fault segments, some of which linked during the Albian-Cenomanian (i.e., 113-100.5 Ma, or the initial 11-13% of their deformation history). Some arrays then reached their near-final length within the subsequent ca. 77 Ma, or the next 69-81% of their deformation history), while others attained this later, during the subsequent ca. 18 Ma (i.e., after 95% of their deformation history). During this time, the segments formed and then breached releasing and restraining stepovers, with the arrays as a whole growing by alternating periods of lengthening, throw accumulation, and inactivity. Our results also show that scatter in the D-L scaling of strike-slip faults reflect the propagation, interaction, and linkage of individual segments.

DOI

https://doi.org/10.31223/X5ND1T

Subjects

Geology, Geophysics and Seismology, Stratigraphy, Tectonics and Structure

Keywords

salt tectonic, Strike-slip Faults, restraining bend, releasing stepover

Dates

Published: 2022-05-25 15:49

Last Updated: 2022-08-25 20:10

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License

CC BY Attribution 4.0 International

Additional Metadata

Data Availability (Reason not available):
The seismic data supporting the findings of this study are available from CGG. However, restrictions apply to the availability of these data, which were used under license for this study.