Metamorphism, structure and stratigraphy of the Park Ranges (western Rocky Mountains), British Columbia

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dc.contributor.advisorGhent, Edward D.
dc.contributor.authorCraw, David
dc.coverage.spatial2000002702en
dc.date.accessioned2005-07-19T20:19:27Z
dc.date.available2005-07-19T20:19:27Z
dc.date.issued1977
dc.descriptionBibliography: p. 129-133.en
dc.description.abstractThe Southern. Park Ranges lie immediately east of the Rocky Mountain Trench, near the Big Bend of the Columbia River, B.C. They are composed of quartzites, pelites and carbonates in an uninterrupted sequence from the Proterozoic Windermere Supergroup, through the Lower Cambrian Gog Group, to the Middle· Cambrian Tsar Creek and Kinbasket units. Two phases of folding and metamorphism are recognized. The first phase of folding (F1) occurred before and during the first phase of metamorphism (M1), while the second phase of folding (F2) was associated with a second (very minor) phase of metamorphism (M2). F1 is seen only as minor structures at the mesoscopic and microscopic scale, although there is some minor-fold vergence evidence for F1 macroscopic structures. F2 structures are seen on microscopic, mesoscopic, and macroscopic scales and are all apparently associated with the Porcupine Creek Anticlinorium, a major fold complex trending NW-SE across the eastern part of the study area. Commonly, F2 folds are nearly concentric with some thickening of incompetent units in the fold hinges. Associated with F2 folds are several west dipping thrust faults, some of which terminate upwards into the cores of F2 anticlines. All structures are cut by late-stage, west-dipping normal faults. Quartz c-axis orientation data show that a distinct postmetamorphic fabric has been imprinted on quartzites near thrust fault and normal fault zones, confirming that both of these fault types are post-metamorphic. The first phase of metamorphism resulted in a Barrovian sequence of .isograds such that chlori te zone rocks occur in the east and sillimanite zone rocks occur in the west. Phase equilibria studies suggest that the metamorphic temperatures in the area ranged from less than 480°c (east)to 570°c (west) _while under a pressure of approximately 5 kb. The pelitic rocks were studied to determine the nature and sequence of prograde metamorphic chemical reactions within the rocks, and the bearing of these reactions on observed textures (e.g., poikiloblastic kyanite). The reactions are depicted on a T-X (Fe-Mg) phase diagram similar to those proposed by Thompson (1976b). Calculations show that potassium released in the reactions almost certainly remained in the rock, causing potassium enrichment of K-bearing phases. The isograds outline a thermal antiform whose western limb is truncated by the Purcell Fault (a major Cordilleran structure) on the western slopes of the study area. A comparison of main metamorphic phases between the Park Ranges and the Selkirk and Monashee Mountains across the Purcell Fault, suggests that the western (Selkirk-Monashee) terrane was subjected to temperatures approximately 40°C higher than the study area (for equivalent metamorphic zones) and a pressure between 2 and 3 kb higher than the study area. This pressure difference suggests that there has been a minimum of 7 km post-metamorphic vertical motion on the Purcell Fault. A difference in structural style across t:;he Purcell Fault, due to a higher ductility in the western terrane, is considered to be a result of the difference in depth during the deformation of the two terranes.
dc.format.extentxiii, 140 leaves : ill. ; 30 cm.en
dc.identifier82480983en
dc.identifier.citationCraw, D. (1977). Metamorphism, structure and stratigraphy of the Park Ranges (western Rocky Mountains), British Columbia (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/12535en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/12535
dc.identifier.lccQE 187 C685 1977 Microficheen
dc.identifier.other82480983en
dc.identifier.urihttp://hdl.handle.net/1880/13775
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.relationAdditional Copy: QE 187 C685 1977G GEOLOGYen
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.subject.lccQE 187 C685 1977 Microficheen
dc.subject.lcshGeology - British Columbia
dc.subject.lcshGeology, Structural
dc.subject.lcshGeology, Stratigraphic
dc.subject.lcshMetamorphism (Geology)
dc.titleMetamorphism, structure and stratigraphy of the Park Ranges (western Rocky Mountains), British Columbia
dc.typemaster thesis
thesis.degree.disciplineGeology
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.item.requestcopyTRUE
ucalgary.thesis.accessionTheses Collection 58.002:Box 283 82480983
ucalgary.thesis.additionalcopyQE 187 C685 1977G GEOLOGYen
ucalgary.thesis.notesPLen
ucalgary.thesis.uarcreleasenoen
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