Economic geology Mineralogy group
Ernst-Moritz-Arndt Universität Greifswald
Institute for Geography and Geology
Friedrich-Ludwig-Jahn-Str. 17A
D-17487 Greifswald

L.N. Warr. Tel. ++49(0)3834 86 4578. E-mail: warr@uni-greifswald.de.
G. Grathoff. Tel. ++49(0)3834 86 4584. E-mail: grathoff@uni-greifswald.de. Secretary. Tel. ++49(0)3834 86 4570. E-mail: geologie@uni-greifswald.de



Holdsworth, R.E., Diggelen, E.W.E., Spiers, C.J., de Bresser, J.H.P., Walker, R.J. & Bowen, L. (2010). Fault rocks from the SAFOD core samples: Implications for weakening at shallow depths along the San Andreas Fault, California. Journal of Structural Geology, 1-13.

This paper describes the features observed in core material of the SAFOD borehole by optical microscopy and SEM. The study highlights the possible linkage between the abundant clay-coated fractures and the creep zones in this part of the San Andreas Fault. It also suggests Mg-smectitic clay mineral phases concentrated in the creep zones are directly responsible for the particularly weak mechanical strength of the fault rock in this zone.