Imperial College London
Portrait Picture

Emeritus ProfessorLidiaLonergan

Faculty of Engineering, Department of Earth Science & Engineering

Emeritus Reader of Geotectonics
 
 
 
//

Contact

 

+44 (0)20 7594 6465l.lonergan Website

 
 
//

Location

 

3.48Royal School of MinesSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Galindo:2021:10.1190/tle40120923.1,
author = {Galindo, PA and Lonergan, L},
doi = {10.1190/tle40120923.1},
journal = {The Leading Edge},
pages = {923--930},
title = {Sigmoidal normal faults and evidence for vertical-axis block rotation in an oblique convergent margin: a 3D seismic example from offshore Colombia},
url = {http://dx.doi.org/10.1190/tle40120923.1},
volume = {40},
year = {2021}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Sigmoidal fold and fault geometries are typical kinematic indicators of strike-slip fault zones. We document kilometer-scale, normal faults with sigmoidal plan-view geometries within the dextral pull-apart Bahia Basin, at the rear of the obliquely convergent South Caribbean Deformed Belt, offshore Colombia. Using 3D seismic reflection data calibrated to wells, closely spaced, low-displacement, planar normal faults are mapped within the Miocene strata. A series of seismic horizontal (time) slices and computed seismic attributes are used to interpret the 3D configuration of these faults. The closely spaced faults display an east–west trend with a progressive rotation into a northwest–southeast trend. In map view, the fault traces curve toward their tips, describing a sigmoidal-Z geometry that terminates at discrete northeast–southwest-trending fault zones. The structures observed may correspond to either tension fractures, which form theoretically at 45°, or antithetic shear fractures with normal displacement formed at 50°–70° to the boundaries of a dextral shear zone. These scenarios lead to a clockwise block rotation of between 20° and 40° within the shear zone. This study shows the first example of vertical-axis block rotations observed offshore in the western end of the South Caribbean margin and is an important example of the use of 3D seismic data to identify rotations where paleomagnetic studies are not available.
AU  - Galindo,PA
AU  - Lonergan,L
DO  - 10.1190/tle40120923.1
EP  - 930
PY  - 2021///
SN  - 1070-485X
SP  - 923
TI  - Sigmoidal normal faults and evidence for vertical-axis block rotation in an oblique convergent margin: a 3D seismic example from offshore Colombia
T2  - The Leading Edge
UR  - http://dx.doi.org/10.1190/tle40120923.1
UR  - http://hdl.handle.net/10044/1/94830
VL  - 40
ER  -
Download