Detailed geologic mapping of the Dycer Creek area and to the north at Last Peak has revealed several major findings: i) rocks of the Teslin Zone and Cassiar Platform are documented on both sides of the fault; ii) regional transposition ST (sub 2) fabrics observed on both sides of the fault are correlative with one another; iii) late km-scale F (sub 3) folding resulted in the modification of a near horizontal regional foliation on both sides of the fault into a steeply dipping orientation. In the hope of better constraining the timing of regional ductile D (sub 2) and D (sub 3) deformation, geochronology samples of four plutonic bodies have been collected during the 1995, 1996 and 1997 field seasons. Initial results of the study are promising as U-Pb dating of zircons from the Mendocina Orthogneiss within the Teslin Zone has confirmed a Devonian age, and dating of monazites from the Dycer Creek Stock and Last Peak Granite has bracketed the age of regional F (sub 3) folding between 113 and 98 Ma. These findings suggest that at least part of the regional deformation may be younger than previously proposed.
A copy of this thesis is available at the EMR library – QE195 G35 1999.
This thesis is available online at https://doi.org/10.22215/etd/1999-04228.