Thesis advisor: J. Christopher Hepburn / The Shrewsbury quadrangle was geologically mapped at a scale of 1:24,000. The quadrangle spans the entire Nashoba terrane, a belt of amphibolite-grade rocks related to an early Paleozoic peri-Gondwanan arc. Petrofabric studies of fault-rocks indicated that the final motion on several major shear zones - Ball Hill fault, Sulfur Hill shear zone, and Assabet River fault - was sinistral strike-slip with an oblique NW over SE thrust component. Monazites from these shear zones were dated using an electron microprobe. Regional metamorphism (M1) took place around 420 Ma. A second regional metamorphism (M2) produced anatectic conditions around 394Ma. A group of dates in the range 360-385 Ma indicates that the Nashoba terrane was also affected by Neoacadian metamorphism and/or deformation. Major shear zones were active throughout the Devonian and may have persisted into the Carboniferous. / Thesis (MS) — Boston College, 2007. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.
| Identifer | oai:union.ndltd.org:BOSTON/oai:dlib.bc.edu:bc-ir_101937 |
| Date | January 2007 |
| Creators | Markwort, Ross Joseph |
| Publisher | Boston College |
| Source Sets | Boston College |
| Language | English |
| Detected Language | English |
| Type | Text, thesis |
| Format | electronic, application/pdf |
| Rights | Copyright is held by the author, with all rights reserved, unless otherwise noted. |
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