Characterization of Structures and Deformation in the Brittle-Ductile Transition, Western Termination of the Chugach Metamorphic Complex, Southern Alaska

Field mapping along the western termination of the Chugach Metamorphic Complex (CMC) revealed a new D2 structure, the Bremner foliation fan. This structure has a high strain, vertically foliated core, with moderate-shallow dipping cleavages to the north and south which rollover into the core. The fan appears to have propagated from below by a shear-zone at depth (O'Driscoll, 2006). Description of the Bremner foliation fan revealed that the Bremner shear zone of Pavlis and Sisson (2003) is a D3 structure, and that the Stuart Creek fault is a younger brittle fault with 90km of dextral offset. Electron Back Scatter Diffraction (EBSD) and microstructural observations revealed deformation mechanisms were primarily compositionally controlled, whereas P-T-t conditions played a secondary role. Other factors, deemed to be of lesser influence included increased pressure solution caused by high fluid mobility, a lack of pore space, high levels of free aluminum, and a load-bearing framework of phyllosilicates.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Geology and Geophysics

Year

2007

Author dc:creator

• Day, Erik

Contributors dc:contributor

• Pavlis, Terry
• Derstler, Kraig
• Kulp, Mark

Repository record dc:identifier

https://scholarworks.uno.edu/td/529

OAI identifier oai:identifier

oai:scholarworks.uno.edu:td-1529