Paleogeography and sedimentology of fluvial point bars, chute-fills and oxbow-fills in the lower Liard River, NWT.

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dc.contributor.advisorSmith, Derald G.
dc.contributor.authorPiet, Leona J. M.
dc.coverage.spatial2000001926en
dc.date.accessioned2005-08-05T16:55:12Z
dc.date.available2005-08-05T16:55:12Z
dc.date.issued1992
dc.descriptionBibliography: p. 101-107.en
dc.description.abstractThe sedimentology and geometry of chute and oxbow channel-fills deposited by meandering rivers are poorly understood. In the ancient fluvial rocks, oxbow-fill deposits are conceptually important stratigraphic traps for small oil and gas prospects and reservoirs in the subsurface. This concept advocates the notion that clay-filled oxbow lakes provide a lateral seal which contains sandy point bar deposits. Why some oxbow traps contain hydrocarbons while others don't has concerned exploration geologists. This study is an attempt to help answer this question by describing the sedimentology and morphology of point bars, chute channel-fills and oxbow-fills in Holocene meandering channel deposits. Terraces up to 18 m high, flanking most reaches of the modern Liard and South Nahanni rivers, NWT, consist of Holocene (5750 BP± 60; GSC-4103) meandering river sediments. Fresh cutbanks have exposed the internal sedimentary anatomy of the river channel: point bar, chute channel-fill and oxbow-fill deposits. The surficial features are so distinct that scroll bar patterns, abandoned channels and oxbow lakes can be easily identified and mapped. The direct association between surface morphology of the floodplain and fluvial stratigraphy, provides a 3-dimensional perspective of a meandering river system and its channel deposits. Aerial photography indicates that the terrace was formerly a floodplain deposited by a meandering river. Exposed sandy point bar deposits are representative of a high energy range of deposition for sandy meandering rivers. The Liard point bar succession was found to be similar to those described in the literature. The chute channelfills, small isolated channel-fills (8 m thick by less than 400 m wide), were dominated by rhythmic-bedded sand and mud. Oxbow-fills were found to have a complex sedimentology contrary to the simplistic all-mud facies presented in most text books. Oxbow-fills have extensive cross-sectional areas, at least 16 m thick and greater than 400 m in width, and are composed of at least 65% thin bedded, fine grained sand. Rhythmic bedding of sand and mud is common. The laterally extensive sand interbeds within the oxbow-fill may not provide impervious stratigraphic traps when deeply buried.
dc.format.extentxvii, 107 leaves : ill. ; 30 cm.en
dc.identifier.citationPiet, L. J. (1992). Paleogeography and sedimentology of fluvial point bars, chute-fills and oxbow-fills in the lower Liard River, NWT. (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/19106en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/19106
dc.identifier.isbn0315790989en
dc.identifier.lccQE 501 P3 P53 1992aen
dc.identifier.urihttp://hdl.handle.net/1880/31161
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.subject.lccQE 501 P3 P53 1992aen
dc.subject.lccAdditional Copy: QE 501 P3 P53 1992en
dc.subject.lcshPaleogeography - Northwest Territories
dc.subject.lcshGlacial landforms - Northwest Territories
dc.subject.lcshGlacial erosion - Northwest Territories
dc.subject.lcshSediment transport - Northwest Territories
dc.subject.lcshAlluvium - Northwest Territories
dc.titlePaleogeography and sedimentology of fluvial point bars, chute-fills and oxbow-fills in the lower Liard River, NWT.
dc.typemaster thesis
thesis.degree.disciplineGeography
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 838 520535172
ucalgary.thesis.additionalcopyQE 501 P3 P53 1992en
ucalgary.thesis.notesoffsiteen
ucalgary.thesis.uarcreleaseyen
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