The nature and timing of movement along the Purcell Thrust, Rocky Mountain Trench, British Columbia

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dc.contributor.advisorKrause, Federico F.
dc.contributor.advisorMoore, J.M.
dc.contributor.authorBoggs, Katherine Janet Elizabeth
dc.date.accessioned2005-08-16T17:36:08Z
dc.date.available2005-08-16T17:36:08Z
dc.date.issued2004
dc.descriptionBibliography: p. 455-479en
dc.description.abstractThe Purcell Thrust (PT) is a classic out-of-sequence thrust, a phenomenon that is not well understood. In the study area, the Purcell Thrust lies in and near the Rocky Mountain Trench (RMT). The Purcell Thrustjuxtaposes the eastern margin of the Selkirk Fan Structure (Dogtooth Duplex) of the Omineca Crystlline Belt over the western margin of the Porcupine Creek Anticlinorium in the western margin of the Rocky Mountain Foreland Belt. Throughout most of the current study area, from the Trans-Canada Highway northwest of Golden, BC to the Big Bend region of the Columbia River, the Purcell Thrust is offset by the Trench Normal Faults (TNF) of the RMT. In both the footwall and hanging wall of the Thrust, metamorphic grade increases from sub-garnet grade in the southeast to migmatites in the northwest (towards the PT). Detailed petrographic studies coupled with electron microprobe analyses determined that garnet is the only mineral that is consistently zoned. Generally, Xpe and Xivig values decrease from the rim to core, while Xca and Xmb values increase from the rim into the core. Thermobarometric calculations using THERMOCALC v3.1 combined with the garnet-biotite thermometer and GASP barometer failed to observe a statistically significant barometric break across the Purcell Thrust. It is possible that movement along a Trench Normal Fault may have disguised this barometric break. Calculations of diffusional penetration distances demonstrated that kyanite + staurolite grade garnets smaller than 5 mm in radius probably had their internal chemistry altered by the affects of retrograde cation diffusion. Fault plane reconstructions of movement along the Purcell Thrust and the Trench Normal Faults demonstrated the existence of at least 10 km of dextral movement along the Purcell Thrust. Geochronology demonstrated that peak regional metamorphism was between 159 and 179 Ma, corresponding to the Jurassic collision of the Intermontane Superterrane with the western margin of ancestral North America. Movement along the Purcell Thrust occurred between 107 and < 85 Ma. This is when the Cretaceous collision of the Insular Superterrane collided with the western margin of ancestral North America. Early Eocene extension coupled with movement along the Trench Normal Fault from 61 to 54 Ma.en
dc.format.extentxiv, 486 leaves : ill. ; 30 cm.en
dc.identifier.citationBoggs, K. J. (2004). The nature and timing of movement along the Purcell Thrust, Rocky Mountain Trench, British Columbia (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/15456en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/15456
dc.identifier.isbn0494039000en
dc.identifier.lccAC1 .T484 2004 B64Aen
dc.identifier.urihttp://hdl.handle.net/1880/42172
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.titleThe nature and timing of movement along the Purcell Thrust, Rocky Mountain Trench, British Columbia
dc.typedoctoral thesis
thesis.degree.disciplineGeology and Geophysics
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 1490 520492007
ucalgary.thesis.additionalcopyAC1 .T484 2004 B64 (Gallagher)en
ucalgary.thesis.additionalcopyAC1 .T484 2004 B64 MAPS (Gallagher)en
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleaseyen
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