Dear list members,
I currently try to separate stress tensors from heterogeneous fault-slip data
collected at the eastern margin of the Tibetian Plateau, where I found six (or
more?) superposed deformation phases (D1 to D6/7/8?) - the first two of which
record ductile, the succeeding phases brittle deformation.
The data set for the brittle faults (D3 to D6/7/8?) comprises the orientation of
the faults and associated slickensides or slickofibres on the fault surface and
the sense of movement derived thereof. Fault planes frequently exhibit two,
seldomly three different sets of lineations. However, overprinting
relationships are usually unclear, as lineations have formed on several
parallel planes within the 1-3 cm width of the fault ("zone") and the
individual layers have weathered off irregularly. Fault planes have therefore
not only been newly built, but have certainly been reactivated and demonstrably
been rotated.
There is some control of the approximate orientation of the paleo- stress-field,
derived from the orientation of fold axes and large-scale shear zones.
For a more precise calculation of the stress tensors from the fault-slip data,
however, I am in need of some computer software capable of differentiating
between tensors of several deformation phases.
Does anyone of you know some software that could perform such operation? I am
aware of the recent publications of
Liesa and Lisle: Realibility of methods to separate stress tensors from
heterogeneous fault-slip data. J Struc Geol, 26 (2004), 559-572
and Yamaji: The multiple inverse method: a new technique to separate stresses
from heterogeneous fault-slip data. J Struc Geol 22 (2000) 441-452 (not so
sucessful with my data)
Any hint is highly appreciated,
Regards
Julia
Dr. Julia Kramer
Postdoctoral Researcher
Economic Geology Research Institute(EGRI)
School of Geosciences
University of the Witwatersrand
Private Bag 3
2050 Wits, Johannesburg
South Africa
Office: +27-11-717 66 11
Mobile phone: +27-72-997 50 72
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