How is Oblique Extension (Transtension) Accommodated from Regional to Local Scales?

Richard R. Jones¹, Sotiris Kokkalas², Dave Healy³, and Ken McCaffrey^3
1Dept. of Earth Sciences, Durham, United Kingdom
²University of Patras, Patras, Greece
³Durham University, Durham, United Kingdom

It is often assumed that mature, crustal-scale fault zones will form major planar lineaments in which smaller scale asperities and irregularities are progressively smoothed and removed during ongoing deformation. New LiDAR data based on detailed terrestrial laser-scans from the Gulf of Evia, Greece, question this view. In this fault zone, active oblique extension is accommodated on arrays of faults that display rhombohedral geometry over several orders of magnitude, from regional to local scale (10m - 100km scale). Rather than forming a single through-going fault plane, it seems that it is more favourable for complex oblique extension (transtension) to be accommodated along multi-scaled arrays of interlinked curvi-planar faults in which the active slip surfaces are comprised of different amalgamations of small fault segments. During progressive deformation, the exact configuration of which active segments of faults are kinematically linked can vary significantly through time.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece