Details

Autor(en) / Beteiligte

• Osagiede, Edoseghe E.
• Rotevatn, Atle
• Gawthorpe, Rob
• Kristensen, Thomas B.
• Jackson, Christopher A-L.
• Marsh, Nicola

Titel

Pre-existing intra-basement shear zones influence growth and geometry of non-colinear normal faults, western Utsira High–Heimdal Terrace, North Sea

Ist Teil von

• Journal of structural geology, 2020-01, Vol.130, p.103908, Article 103908

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Pre-existing intra-basement shear zones can induce mechanical and rheological heterogeneities that may influence rifting and the overall geometry of rift-related normal faults. However, the extent to which physical and kinematic interaction between pre-existing shear zones and younger rift faults control the growth of normal faults is less-well understood. Using 3D reflection seismic data from the northern North Sea and quantitative fault analysis, we constrain the 3D relationship between pre-existing basement shear zones, and the geometry, evolution, and synrift depositional architecture of subsequent rift-related normal faults. We identify NE-SW- and N-S-striking rift faults that define a coeval Middle Jurassic – Early Cretaceous, non-colinear fault network. NE-SW-striking faults are parallel to underlying intra-basement shear zone. The faults either tip-out above or physically merge with the underlying shear zone. For faults that merges with the basement shear zone, a change from tabular to wedge-shaped geometry of the hangingwall synrift strata records a transition from non-rotational to rotational extension faulting, which we attribute to the time of rift fault's linkage with the shear zone, following downward propagation of its lower tip. N-S-striking faults are oblique to, and offset (rather than link with) intra-basement shear zones. These observations highlight the selective influence pre-existing intra-basement shear zones may (or may not) have on evolving rift-related normal faults. •Basement inheritance control the development of coeval non-colinear rift fault network.•Linkage between rift faults and basement shear zone causes transition from non-rotational to rotational faulting.•Onset of low-angle, rotational faulting is associated with a corresponding change in syn-rift stratigraphic architecture.•Pre-linkage growth strata is tabular whereas syn- and post-linkage growth strata is wedge-shaped.