Paleogeography and sedimentology of the MacKenzie Basin, Northwest Territories, Canada: An evaluation of Devonian sea-level change, paleoecological controls on Paleozoic reef growth, and early diagenetic conditions.Reportar como inadecuado




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Devonian, eustatic, Paleozoic, sea-level

Corlett, Hilary

Supervisor and department: Jones, Brian Department of Earth and Atmospheric Sciences

Examining committee member and department: Leys, Sally Department of Biological Sciences Qing, Hairuo Department of Geology, University of Regina Gingras, Murray Department of Earth and Atmospheric Sciences Leighton, Lindsey Department of Earth and Atmospheric Sciences Muehlenbachs, Karlis Department of Earth and Atmospheric Sciences

Department: Department of Earth and Atmospheric Sciences

Specialization:

Date accepted: 2011-05-17T19:40:08Z

Graduation date: 2011-11

Degree: Doctor of Philosophy

Degree level: Doctoral

Abstract: The MacKenzie Basin, located in the District of MacKenzie in thesouthern part of the Northwest Territories, Canada, includes a thick succession of Middle Devonian strata. This basin, bordered to the east by the Canadian Shield and to the south by the Tathlina Uplift, was directly connected to the open ocean that lay to the northwest. Comprehensive facies analyses of the Chinchaga Formation, Lonely Bay Formation, Horn Plateau Formation, and Horn River Formation, which formed in this basin during the Early and Middle Devonian, shows that sedimentation was largely controlled by eustatic sea level changes. Accordingly, these strata reflect a long period of sea level rise during which shallow water evaporite deposition in the Eifelian was followed by open marine conditions that led to reef growth in the Givetian, and ultimately pelagic shale deposition in the Frasnian.The Horn Plateau Formation is comprised of numerous isolated reefsthat are located along northeast-southwest direction over a distance of 350 km along the MacKenzie Basin ramp. Reefs in the southwest are dominated bystromatoporoids whereas those in the northeast are dominated by corals. Although difficult to prove, it appears that the distribution of the stromatoporoids and corals may have been controlled by nutrients coming from coastal upwelling or runoff from the exposed Canadian Shield.Effects of early diagenetic processes were evident on the MacKenzieBasin ramp in an intensely bioturbated facies in the Lonely Bay Formation.Burrows from this facies are dolomite-filled further down the ramp and calcite-filled proximal to the Canadian Shield in the east. Anoxic conditions and thepresence of sulphate reducing bacteria may have promoted early dolomiteformation in the burrows located in deeper water. Burrows further up the ramp were oxygenated and show evidence of input from the exposed Canadian Shield, both of which may have inhibited low-temperature dolomite formation.

Language: English

DOI: doi:10.7939-R3FM84

Rights: License granted by Hilary Corlett hcorlett@ualberta.ca on 2011-05-17T18:11:34Z GMT: Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of the above terms. The author reserves all other publication and other rights in association with the copyright in the thesis, and except as herein provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.





Autor: Corlett, Hilary

Fuente: https://era.library.ualberta.ca/


Introducción



University of Alberta Paleogeography and sedimentology of the MacKenzie Basin, Northwest Territories, Canada: An evaluation of Devonian sea-level change, paleoecological controls on Paleozoic reef growth, and early diagenetic conditions. by Hilary Jean Corlett A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Earth and Atmospheric Sciences Edmonton, Alberta Fall 2011 ABSTRACT The MacKenzie Basin, located in the District of MacKenzie in the southern part of the Northwest Territories, Canada, includes a thick succession of Middle Devonian strata.
This basin, bordered to the east by the Canadian Shield and to the south by the Tathlina Uplift, was directly connected to the open ocean that lay to the northwest.
Comprehensive facies analyses of the Chinchaga Formation, Lonely Bay Formation, Horn Plateau Formation, and Horn River Formation, which formed in this basin during the Early and Middle Devonian, shows that sedimentation was largely controlled by eustatic sea level changes. Accordingly, these strata reflect a long period of sea level rise during which shallow water evaporite deposition in the Eifelian was followed by open marine conditions that led to reef growth in the Givetian, and ultimately pelagic shale deposition in the Frasnian. The Horn Plateau Formation is comprised of numerous isolated reefs that are located along northeast-southwest direction over a distance of 350 km along the MacKenzie Basin ramp.
Reefs in the southwest are dominated by stromatoporoids whereas those in the northeast are dominated by corals.
Although difficult to prove, it appears that the distribution of the stromatoporoids and corals may have been controlled by nutrients coming from coastal upwelling or runoff from the exposed Canadian Shield. Effects of early diagenetic processes were evident on the MacKenzie Basin ramp in an intensely bioturbated facies...





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