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Analysis of Brittle Faulting
in the Prince
Rupert Area, Coast Mountains, British Columbia
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).
thesis was part of a Keck-sponsored project led by Cam Davisdon, now at
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
can be downloaded here:
Table of Contents
Thesis text only
Full thesis (140 MB) (103 p.)
(The images are not well-compressed in the thesis; hence it is 140 MB,
fault rock from Prince Rupert area, British Columbia (Figure 19a of
Field area of
study, western British Columbia (Figure 1 of thesis).
through-road runs along the Skeena River, running perpendicular to the
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).
Figure 47b from my thesis and Figure 23 from our GSA poster)
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
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,
the slip on all four faces occurred
under the same stress regime.