Basement-Controlled Deformation of Sedimentary Sequences, Anadarko Shelf, Oklahoma

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1111/bre.12433.

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Authors

Folarin Kolawole , Molly Simpson Turko, Brett Carpenter

Abstract

Structures rooted in the crystalline basement frequently control the deformation of the host bedrock and the overlying sedimentary sequences. Here, we elucidate the structure of the c. 2‐km deep Precambrian granitic basement in the Anadarko Shelf, Oklahoma, and how the propagation of basement faults deformed the sedimentary cover. Although the basin is foreland in origin, the gently dipping shelf sequences experienced transpressional deformation in the Late Palaeozoic. We analyse a 3‐D seismic reflection data set and basement penetrating well data in an area of 824 km2. We observe: (a) pervasive deformation of the basement by basement‐bounded interconnected mafic sills, and a system of subvertical discontinuity planes (interpreted as faults) of which some penetrate the overlying sedimentary cover; (b) three large (>10 km‐long) through‐going faults, with relatively small (<100 m) vertical separation (Vsep) of the deformed stratigraphic surfaces; (c) upward propagation of the large faults characterized by faulted‐blocks near the basement, and faulted‐monoclines in the deeper sedimentary units that transition into open monoclinal flexures up‐section; (d) cumulative along‐fault deformation of the stratigraphy exhibits systematic trends that varies with offset accrual; (e) two styles of Vsep-Depth distribution which include a unidirectional decrease of Vsep from the basement through the cover rocks (Style‐1) and a bidirectional decrease of Vsep from a deep sedimentary unit towards the basement and shallower sequences (Style‐2). We find that the basement‐driven propagation (Style‐1) shows greater efficiency of driving the fault deformation to shallower depths compared to the intrasedimentary‐driven fault nucleation and propagation (Style‐2). Our study demonstrates an evolution of cumulative Vsep trends with offset accrual on the faults, and the partial inheritance of the heterogeneous intra‐basement deformation by the sedimentary cover. This contribution provides important insight into the upward propagation of basement‐driven faulting associated with structural inheritance in contractional sedimentary basins.

DOI

https://doi.org/10.31223/osf.io/up497

Subjects

Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

Basement faults, Fault propagation, Igneous sills, Intrabasement reflectors, Strike-slip fault, Structural inheritance, Transpression

Dates

Published: 2020-07-30 13:51

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License

CC BY Attribution 4.0 International

Additional Metadata

Data Availability (Reason not available):
The 3-D seismic dataset that support the findings of this study are available on request from TGS (global.marketing@tgs.com). However, the vertical separation and geochemical data (XRD and XRF) that support the findings of this work are available as supplementary files of this manuscript.

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