Zeolitization of the Howson facies, Telkwa Formation, British Columbia

Simple item page
dc.contributor.advisorGhent, Edward D.
dc.contributor.authorDudley, Jon Steven
dc.coverage.spatial2000002239en
dc.date.accessioned2005-07-21T20:23:36Z
dc.date.available2005-07-21T20:23:36Z
dc.date.issued1983
dc.descriptionBibliography: p. 283-302.en
dc.description.abstractZeolites in the Howson facies of the Lower Jurassic Telkwa Formation, north-central British Columbia, include analcime, wairakite, laurnontite, thomsonite, mesolite, scolecite, stilbite, and heulandite. Electron microprobe anlyses of these zeolites show close agreement with ideal end-member compositions. The Howson facies zeolitization occurred in a regime of high temperature/pressure ratio typical of geothermal fields. Published stratigraphic reconstruction indicates a maximum burial depth during zeolitization of 4 kilometres. This corresponds to a maximum load of approximately 102 MPa. Comparison of the zeolite assemblage to published experimental data suggests a maximum temperature of 350°C for zeolitization of the Howson facies. Minimum pressures and temperatures could have been close to surface values. Zeolitization of the Howson facies was governed by physicochemical variables associated with the movement of fluids of variable temperature and composition through rock of varying permeability and composition. A high water/rock ratio is suggested by extensive occurrences of amygdules and groundmass replacement comprising up to 80% of the rock, veins and fracture breccia cements which in many instances bear no compositional relationship to the bulk rock composition, and the preferential alteration of initially more permeable strata. The complex stratigraphic distribution of zeolites in the Howson facies cannot be interpreted as a progressive dehydration with increasing depth and temperature. Paragenetic sequences can be explained only in part by a decreasing temperature with time. In some instances fracture permeability controlled the degree of hydration of the stable zeolite. Isolated groundmass zeolite occurrences were controlled by the composition of the host rock, whereas those occurrences associated with veins or fracture breccia cements involved external buffering of the fluid chemistry and mass transfer. Evolution of fluid chemistry with progressive interaction of meteoric water and volcanic rock can explain some, but not all, of the paragenetic sequences observed in the Howson facies. Changes in fluid chemistry associated with processes such as boiling can explain parts of paragenetic sequences such as late calcite in veins and fracture breccia cements. The regional distribution of zeolites within the Howson facies was controlled by changes in rock composition, temperature, and origin of the groundwater away from the volcanic centre toward the eastern boundary of the facies which is marked by a paleo-shoreline.
dc.description.notesThis title is not available online. Access options are: - consulting the copy from Archives in our reading room in person - https://asc.ucalgary.ca/visiting/ - borrowing a circulating copy from the Library catalogue – https://ucalgary.primo.exlibrisgroup.com/discovery/search?vid=01UCALG_INST:UCALGARY&lang=en
dc.format.extentxxii, 302 leaves : ill. ; 30 cm.en
dc.identifier.citationDudley, J. S. (1983). Zeolitization of the Howson facies, Telkwa Formation, British Columbia (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/12837en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/12837
dc.identifier.lccQE 391 Z5 D82 1985en
dc.identifier.otherNL Number: 66215en
dc.identifier.urihttp://hdl.handle.net/1880/22706
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.relationAdditional Copy: QE 391 Z5 D82 1983en
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 391 Z5 D82 1985en
dc.subject.lcshZeolites - British Columbia - Telkwa Formation
dc.subject.lcshGeology - British Columbia - Telkwa Formation
dc.titleZeolitization of the Howson facies, Telkwa Formation, British Columbia
dc.typedoctoral thesis
thesis.degree.disciplineGeology and Geophysics
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.thesis.accessionTheses Collection 58.002:Box 472 82483996
ucalgary.thesis.additionalcopyQE 391 Z5 D82 1983en
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleasenoen
Files
Collections
Restricted Theses and Dissertations