50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
eneath the detachment involved a component of<br />
simple shear parallel to the lineation with a top-tothe<br />
NE sense-of-shear. High-temperature quartz<br />
and feldspar deformation mechanisms, and minimal<br />
retrogression suggest that the lower plate tectonites<br />
preserve an early snapshot of extensional fabrics in<br />
the lower crust. These fabrics are preserved<br />
because they were exhumed by dominantly brittle<br />
processes, involving localised slip on a deeply<br />
penetrating detachment fault that transects the<br />
middle crust. Localisation of slip on the fault could<br />
be due to a weakening effect of high strain-rates on<br />
fault gouge material or deep embrittlement caused<br />
by prolonged maintenance of high pore-fluid<br />
pressures or high strain rates.<br />
ORAL<br />
LATE QUATERNARY LARGE-SCALE<br />
ROCK-MASS DEFECT CONTROLLED<br />
LANDSLIDES <strong>OF</strong> EASTERN NORTH<br />
ISLAND, <strong>NEW</strong> ZEALAND: TECTONIC AND<br />
CLIMATIC FORCING IN LANDSCAPE<br />
EVOLUTION<br />
Jarg Pettinga 1 ,JimMcKean 2 , Joshu Mountjoy 1 ,<br />
Verne Pere 1 , Kerry Leith 1 & Ben Mackey 1<br />
1 Geological Sciences, University of Canterbury,<br />
P.B. 4800, Christchurch, New Zealand<br />
2 USDA Forest Service, Rocky Mountain Research<br />
Station, 316 E. Myrtle Street, Boise, ID 83702 USA<br />
(jarg.pettinga*canterbury.ac.nz)<br />
Rock mass defect controlled landslides are<br />
widespread in the Tertiary bedded marine soft rock<br />
terrain of eastern North Island. The location and<br />
frequency of these deep-seated bedrock landslides<br />
is somewhat predictable and the slides are a<br />
dominant process affecting both sediment fluxes<br />
and landscape evolution. Most slides appear to be<br />
base level controlled and occur after stream incision<br />
has exposed a critical stratigraphic horizon,<br />
defined by thin (typically