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UMS Sedimentology, Sea-Level Hlstory, and Tectonic Context of a Mesoproterozoic Carbonate Ramp, Baffin Island, Nunavut Anne Geneviève Sherman A thesis submitted to the Department of Geological Sciences and Geological Engineering in conformity with the requirements for the degree of Doctor of Philosophy Queen's University Kingston, Ontario, Canada March, 2001 copyright O Anne Genevieve Shem2001 National Li'brary Bibliothèque nationale du Canada Acquisitions and Acquisitions et Bibliographie Services seivices bibliographiques 395 Wellhqml Street 395. rue Wdlnigîon OttawaON KlAON4 OttawaON KtAON4 canada Canada The author has ganted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant a la National Library of Canada to Bibliothèque nationale du Canada de reproduce, Ioan, distribute or selI reproduire, prêter, distriibuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownershrp of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or othewise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. QUEEN'S UNiVERSiTY AT KINGSTON SCHOOL OF GRADUAE STUDIES AND RESEARCH PERMISSION OF CO-AUTHORS Mm, the undersigned, hereby grant permission to microfilm any material designated as being coguthored by melus in the thesis copyrighted to the person named below: 6-S&/ma, Name of copyrighted author Name(s) of coauthar(s) Signatures of CO-author(s) Yiews ofthe Vicror Bay Formation Cllrs of sîrongiy cyclic shallow-waier limestone overlying recessive deep-wuter shale in the Ector Bay Formation. Field of view is 1.5 kilo~etmwide and contains part of the eastern wu11 ofPmgo Valley, Sirnirlik National Purk nwthem B@n Island. DarA limestone cl* of the 450-metmthick Yictor Bay Fornatron merlyingpale Society CZ#i dolosones, togetherfonnihgpart of the Pmcipitopls Mountains alung the western shore of Tremblay Sm4 notthm BeIdand ABSTRACT The -1.2 Ga Victor Bay Formation is a -300-600-m-thick succession of predominantly carbonate rocks within the Mesoproterozoic Borden Basin of northem Baffin Island in Arctic Canada. These sediments are dominated by lime mudstone facies and, given their Precambrian age, contain an anomalously Iow proportion of shallow-water stromatolitic rocks. They fom one of the first examples of a Phanerozoic-style carbonate ramp, and reflect the interplay between sea level and tectonics during a critical period in the evolution of the Borden Basin aulacogen. Of the wide spectrum of carbonate depositional systems that had evolved by the late Mesoproterozoic, the Victor Bay ramp succession represents a muddy endmember wherein the carbonate factory produced lime mud in far greater amounts than ooids, microbialites, or benthic precipitates combined. Lime rnud precipitated from the water column and grains fomed by early lithification of the muddy sediments. Episodic storms generated a variety of intraclast particles and redistributed mud and grains on this otherwise Iow-energy microtidal ramp. Stromatolites were deposited only when accommodation space increased rapidly, but during such times flourished and accumulated as large reefs. The ramp carbonates are demonstrably cyclic at several scales. Most are packaged in decametre-scale cycles of 2û-50 rn, thicknesses that exceed those of classic shallowing- upward cycles by a hctor of ten. Three types of cycles are recognized: (1) deep-subtidal cycles on the outer-ramp, with black dolomitic shale at the base overlain by ribbon, nodular, and carbonaceous carbonate facies, al1 of which exhibit signs of synsedimentary dimption; (2) shallow-subtidal cycles with basal deepwater facies and an upper layer of subtidal rnolar- tooth limestone tempestite interbedded with microspar calcarenite facies; and (3) pentidal cycles similar to shallow-subtidal cycles and capped by dolomitic tidai-flat microbia1 Iarninite, red shale sabkha facies and sandy polymictic conglomerate. Maximum progradation of Uuier- ramp tidal Bats over outer- and mid-mp facies during shoaling coincides with a zone of slope failure that may have created accommodation space and therefore promoted the development of the stromatolitic reefs. Consistently thick and cornplete decametre-scale cycles are compatible with the rapid creation of accommodation space during high-amplitude, high-frequency eustasy. A glacio-eustatic interpretation of these cycles supports the global climatic supercycle theory that predicts icehouse conditions in the Iate Mesoproterozoic. At the hectometre scale, the eustatic signal was overprinted by pulses of tectonism that defined major sequence-bounding unconfonnities and flooding surfaces. Tectonic effects bdamentally altered patterns of sedimentation in the Borden Basin during Victor Bay the. Regional correlations indicate that during deposition of the carbonate ramp, the overall deepening trend within the basin was reversed, leading to karsting in the west and drowning in the east. This sequence of events and the disruption of the paleogeography across the structural grain of the aulacogen are best reconciled with reactivation of basement faults in a foreland basin setting. This new interpretation is consistent with observations of late Mesoproterozoic deformation in the northwestern Arctic. CO-AUTHORSHIP The following work is my own, but owes its final form to input from Dr. Noel James and Dr. Guy Narbonne. niey are CO-authorson the three manuscripts and contributed in both a scientific and editorial role. The two published manuscripts were improved both conceptually and stylistically by J.P. Groizinger, P.N. Southgate, M.E. Tucker, J.F. Read, J.B. Southard, and D. Pettyjohn. The third paper benefited greatly fiom recommendations by H.T. Helmstaedt. ACKNOWLEDGEMENTS This tome is the distillation of several years of work, and it presents new information and ideas. Iust as importantly, it represents the tremendous gift of knowledge, guidance, patience, and support contributed by Noel lames and Guy Narbonne in thrir role as advisors. Their example helped me understand the real work behind the science: how to ask questions, how to approach problems, and how to communicate results. Al1 my thanks to you both for fostenng an ideal learning environment with good advice and an open door. Whenever we "taked shop", your dynamism and perspective unfailingly renewed my enthusiasm and promoted new ways of thinking. 1 consider myself extremely fortunate to have had two exceptional advison during my time here. Thank you also for accepting the spasmodic Pace of my progress through many work stints and the usual complement of persona1 complications that corne with being Homo supiens. A special note of appreciation, Guy, for showing me how a real geologist crosses a Stream; and Noel, for teaching us that lunchtime means Merlot. A big thanks to Jason Harrington for Kraft Suppers, mernorable Lindsay stories, and excellent field assistance. 1 was fortunate to find someone masochistic enough to put up with me for one summer, let alone two. This project would not have possible without logistical support from the Polar Continental Shelf Project, with special thanks to Resolute base managers Ji.Godden and Dave Maloley, and crews from BradleyEirst Air and Canadian Helicopters. Staff at Nanisivik Mine, especially Gary Dyck, Jack Haynes, Noel Hedges, and Ron Sutherland, are thanked for generously providing storage space, a mine tour, and many truck rides up the hill. The communities of Arctic Bay and Pond Inlet are thanked for permission to conduct research on their land. Financial support for the project was provided by the Natural Sciences and Engineering Research CounciI, the Northern Studies Training Program, a GSA Research Grant, and a Queen's Doctoral Travel Grant. The Department of Geological Sciences and Geological Engineering and the School of Graduate Studies are thanked for financial assistance through scholarships, gants, and teaching assistantships. Technical and administrative assistance from staff membea is much appreciated, especially Rob Renaud, Greg Hounsell, Ela Rusak, Jerzy Adwent, Roger I~es,Dianne Hyde, Joan Charbonneau, Linda Anderson, Ellen Mulder, Hanne Sherbonneau, and Larke Zarichny. Thanks to Bill Macfarlane for his help with photographie prints. One of the pleasures of pduate school is the opportunity to meet and interact with exceptional people. To leff Lukasik, Dave Scott, and Liz Turner, my sincere gratitude for many years of fkiendship, advice, and support. 1 can't possibly summarize it al1 here, so 1 wonlt even try! Thanks go out to Tom Ullrich for aesthetic counsel of al1 kinds, Jeny Grant for improving the student body through hockey, Sara Ryan for coffee & chick-talk, Kasper Frederiksen for sharing many ideas during his short visit, fellow Borden Babe Linda Kah for fruitfil discussions and collaboration, also Vicki Bannister, Frank Brunton, Cathy Corrigan, Dave Kerr, Annukka Lipponen, Dave Love, Annette MacIlroy, Sarah Palmer, Amelia Rainbow, Clare Robinson, Ian Russell, Gord Stretch, Marian Warren, Don Wood, Karen Wright, and a string of tolerant officemates. Merci aussi à Doug Archibald, Herb Helmsatedt,