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Kinematic Analysis of Brittle Faulting

My undergraduate thesis in geology at Carleton College (2001) involved measuring and analyzing a population of faults in the vicinity of Coast Shear Zone in western British Columbia.  I computed P-T axes of the faults that had slip sense preserved by the slicksides on the surface.  I also examined the assocated fault rocks at multiple scales (outcrop, hand sample, thin section, SEM).  My thesis was part of a Keck-sponsored project led by Cam Davisdon, now at Carleton College.

Some of the analysis was incorporated into a paper published in
Geology by Davidson, Davis, Bailey, Tape, Singleton, Singer (pdf).

A nice overview can be found in our 2001 GSA poster:
left panel (15 MB), right panel (27 MB)

The thesis (PDF format) can be downloaded here:
Abstract
Table of Contents
Thesis text only
References
Full thesis (140 MB) (103 p.)

(The images are not well-compressed in the thesis; hence it is 140 MB, unfortunately.)

Other links:
Carleton College
Carleton Geology Department
Carleton Physics Department


A beautiful fault rock from Prince Rupert area, British Columbia (Figure 19a of thesis).


Field area of study, western British Columbia (Figure 1 of thesis).
The primary through-road runs along the Skeena River, running perpendicular to the terranes.



Three significant fault groups in the study region (modified Figure 38 from thesis). (pdf)

Synthesis of ductile and brittle deformation in the study area (pdf). (modified Figure 47b from my thesis and Figure 23 from our GSA poster) The three colored boxes correspond to the fault sets plotted above.  The indicated timing of the normal faulting (52 Ma) is somwhat later that what I proposed in my thesis (65 Ma), and somewhat earlier than what we proposed on our 2001 GSA poster (42 Ma).  A key observation is the structural evidence of extensional collapse in the east region at 52 Ma (Hollister and Adronicos, EPSL, 2006).  This is not listed in the plot above.

A kinematically compatible rock (Figure 41 of thesis).
This rock has four distinct surfaces with sense-of-slip.
For each face we can compute the P-T axes with respect to the foliation plane.
In this case, all four sets of P-T axes cluster near the same area,
suggesting that the slip on all four faces occurred under the same stress regime.