Geometrical analysis of the refraction and segmentation of normal faults in periodically layered sequences

Autor(en)

M.P.J. Schöpfer, C. Childs, J.J. Walsh, T. Manzocchi, H.A. Koyi

Abstrakt

Normal faults contained in multilayers are often characterised by dip refraction, which is generally attributed to differences in the mechanical properties of the layers, sometimes leading to different modes of fracture. Because existing theoretical and numerical schemes are not yet capable of predicting the 3D geometries of normal faults through inclined multilayer sequences, a simple geometric model is developed, which predicts that such faults should show either strike refraction or fault segmentation, or both. From a purely geometrical point of view, a continuous refracting normal fault will exhibit strike (i.e. map view) refraction in different lithologies if the intersection lineation of fault and bedding is inclined. An alternative outcome of dip refraction in inclined multilayers is the formation of segmented faults exhibiting en échelon geometry. The degree of fault segmentation should increase with increasing dip of bedding, and a higher degree of segmentation is expected in less abundant lithologies. Strike changes and associated fault segmentation predicted by our geometrical model are tested using experimental analogue modelling. The modelling reveals that normal faults refracting from pure dip-slip predefined faults into an overlying (sand) cover will, as predicted, exhibit systematically stepping segments if the base of the cover is inclined.

Organisation(en)

Institut für Geologie

Externe Organisation(en)

Uppsala University, University College Dublin

Journal

Journal of Structural Geology

Band

29

Seiten

318-335

Anzahl der Seiten

18

ISSN

0191-8141

DOI

https://doi.org/10.1016/j.jsg.2006.08.006

Publikationsdatum

02-2007

Peer-reviewed

Ja

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/f282b4aa-817e-4034-9124-a7d435faca91