Melville Island's salt-based fold belt (Arctic Canada)

dc.contributor.advisorBally, Albert W.
dc.creatorHarrison, John Christopher
dc.date.accessioned2009-06-04T00:15:34Z
dc.date.available2009-06-04T00:15:34Z
dc.date.issued1991
dc.description.abstractMelville Island lies astride the Cambrian through Devonian Arctic Platform, correlative rocks of the Franklinian Mobile Belt and, unconformable post-Devonian cover of the Sverdrup Basin. Seismic profiles and a revised geology map provide insight into Melville Island bedrock structure spanning a billion years of earth history to depths exceeding 20 km. Structures at the deepest levels include possible ?Precambrian crystalline basement and three ?Proterozoic seismic successions deformed and eroded prior to unconformable overlap by ?Lower Cambrian strata. Over a south to north distance of 300 km, the ?Cambrian through Devonian shelf-marginal wedge increases from 1200 m to at least 12500 m in thickness. The overlying Devonian clastic wedge (3000 to 4600 m) represents the depositional record of the ancestral Ellesmerian Orogeny. deformation that eventually terminated lower Paleozoic sedimentation. This southerly-directed deformation produced large contractional features on the island, and a salt-based fold belt that dominates surface structure. The fold belt is continuous downwards with: a seismically-imaged, folded and thrust faulted interval with up to 28 km (15%) horizontal shortening; a basal detachment at 5 km, and; an array of southerly- and northerly-transported thrusts most of which fail to appear at surface. Elements of a younger Ellesmerian deformation phase, recognized in surface cross-fold axes, are also mapped within the folded sub-salt succession below 5 km. Ellesmerian deformation continues to the west where style is related to slip on a ?mid-Cambrian detachment. Thrusts that ramp up to the sub-salt decollement have produced large anticlinoria near the present margin of the Sverdrup Basin. These faults have been repeatedly reactivated since the ?Precambrian. Recognized phases include: a N40-10$\sp\circ$W-directed Late ?Proterozoic extension; mid-?Cambrian growth faulting; two phase sinistral transpressive inversion of these extensional structures during the Ellesmerian Orogeny; northerly-directed rifting of Sverdrup Basin in the Carboniferous; inversion of the rift zone during the mid-Permian; evaporite diapirism and magmatic activity in the Jurassic and pre-Albian Cretaceous; southwesterly-directed sinistral transpressive adjustments coeval with the mid-Tertiary Eurekan Orogeny, and; a final phase of uplift and continuing seismicity.
dc.format.extent1166 p.en_US
dc.format.mimetypeapplication/pdf
dc.identifier.callnoThesis Geol. 1991 Harrison
dc.identifier.citationHarrison, John Christopher. "Melville Island's salt-based fold belt (Arctic Canada)." (1991) Diss., Rice University. <a href="https://hdl.handle.net/1911/16447">https://hdl.handle.net/1911/16447</a>.
dc.identifier.urihttps://hdl.handle.net/1911/16447
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectGeology
dc.subjectGeophysics
dc.titleMelville Island's salt-based fold belt (Arctic Canada)
dc.typeThesis
dc.type.genremaps
dc.type.materialText
thesis.degree.departmentEarth Science
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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Simplified correlation chart with major geologic events and tectonic transport directions, Precambrian-Recent of the Melville Island region
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Melville Island and adjacent small islands, eastern map
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Melville Island and adjacent small islands, western map