Department or Program

Geology

Abstract

The Sandhill Corner shear zone is the longest continuous strand of deformation within the Norumbega Fault System (NFS). The Norumbega is a dextral fault system that extends from New Hampshire into New Brunswick. This study uses recrystallized grain size piezometry and quartz flow laws to determine the total offset on the Sandhill Corner shear zone (SCsz). Recrystallized quartz grains were measured and quartz crystallographic preferred orientations (CPO) were determined in three samples using SEM-EBSD. Differential stress and deformation temperature can be estimated from these data and then used to calculate strain rate and total shear zone offset. Calculating the quartz c-axis fabrics made it possible to determine the deformation temperature, these temperatures ranged from 400±50ºc to 500±50ºc. Differential stress ranged between 47.5-60.1MPa, the strain rate ranged between 1.44x10-13s-1 and 3.73x10-13s-1 and the plate velocity estimates were between 0.45-1.18cm/year. Previous estimates of the total displacement across the Norumbega fault system and the Sandhill Corner shear zone range widely, from 25-1900km. Based on a previously well-established regional cooling history there was significant plate movement during a 30-million-year period. Based on deformation temperature and published Ar-Ar dating, it was possible to estimate that this shear zone was deforming between 370 million years ago to 340 million years ago. It was possible to get an estimated total distance of displacement between 136-353km

Level of Access

Open Access

First Advisor

<-- Please Select One -->

Date of Graduation

5-2020

Degree Name

Bachelor of Arts

Number of Pages

53

Download

Open Access

Available to all.

Share

COinS