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National Library Bibliothèque nationale du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington OttawaON K1AON4 Ottawa ON K1A ON4 Canada Canada Your file Votre réference Our rile Noire refdrence The author has granted a non- L'auteur a accorde une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la fome de microfichelfilm, de reproduction sur papier ou sur format électronique. The author retains ownership 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 £iom it Ni la thèse ni des extraits substantiels may be p~tedor otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. BIOSTRATIGRAPHY OF THE LOWER ORDOVICIAN CHITINOZOA OF WESTERN NEWFOUNDLAND, CANADA by Randy S.R. Batten @.Sc. Hons.) A thesis submitted to the School of Graduate Studies in partial fulfilrnent of the requirements for the degree of Master of Science Department of Earth Sciences Mernorial University of Ne wfoundland July 2000 St. John's Newfoundland ABSTRACT The Cow Head Group of western Newfoundland, lying exposed within shoreline sections between Bonne Bay and Portland Creek, represents an aIlochthonous sediment apron or toe deposit at the base of an ancient carbonate-rich continental rnargin. While it ha been studied extensively for a varïety of fossil species, few accounts exist for chitinozoa in this stratigraphically important section. For this study, a detailed analysis of samples from 6 sections across the Lower Ordovician Cow Head Group recovered 32 species of well- preserved chitinozoan. In addition, 22 taxa of uncertain specific designation have been identified which represent 9 genera (Amphorachitina, Belonechitina, Conochitina, Desmochitina, Eremochitina, Lagenochitina, Laufeldochitina, Rhabdochitina, and Tanuchitina), and include several species that have never been documented from western Newfoundland. Frequent occurrence of biostratigraphicaIIy useful species (Arnphorachitina con@ndas7 Conochitina brevis, Conochitina langei, Conochitina raymondi, Conochitina symmeîrica, Lagenochitina esthonica and Lagenochitina destombesi) indicate 4 Lower Ordovician chitinozoan biozones (Amphorachitina conzfindas Zone, Conochitina symrnetrica Zone, Lagenochitina esthonica / Conochitina raymondi Zone, Conochitina langei / Conochitina brevis Zone), and 2 proposed biozones (Cyathochitina dispar Zone, Laufeldochitina sp. Zone) that are unique to Newfoundland. Together, these zones span the upper Tremadoc through the entire Arenig, and correlate well with equivalent sections fiom North Amenca, Europe, north Afkica and Australia. While Amphorachitina conifundas and Lagenochitina destombesi have not previously been reported within North Arnencan sections, their persistence in western Newfoundland establishes a strong affinity between Laurentian and Gondwanan sections that has not been docurnented within eastem Canada- A prelirninary investigation of species distribution suggests a number of taxa (Conochitina, Rhubdochitina and Lugenochitina spp.) may show preference for either shallow (proximal) or deep water (distal) deposits dong the lower carbonate slope of the Cow Head Grouy. Whether this refiects either physical reworking and sediment transport, or the result of ecological influences is largely speculative. From the present study it is clear that the distributional controls on chitinozoa within the Cow Head Group are indeed cornplex, and likeiy influenced by an array of sedimentological and biological processes. TABLE OF CONTENTS ABSTRACT ............................................................. i ... TABLE OF CONTENTS ................................................... ri1 ILLUSTRATIONS ....................................................... vi List of Text-Figures ................................................vi * . List of Tables ..................................................... vil ... ACKNO WLEDGEMENTS ................................................. viii CHAPTER 1: JNTRODUCTION ........................................... 1 1.1 Introduction .................................................... 1 1.2 History of Research .............................................. -3 1.3 Geology of the Cow Head Region ................................... 8 1.3.1 Stratigraphy ............................................ -8 1.3.2 Paieontology ........................................... 14 CHAPTER 2: METHODOLOGY ............................................ 17 2.1 Collecting ...................................................... 17 2.2Processhg ..................................................... 17 2.2.1 Carbonate Dissolution .................................... 18 2.2.2 Silica Dissolution ........................................ 19 2.2.3 Picking and Counting ..................................... 19 2.3 Study Material ................................................ -20 2.4 SEM Stub Preparation ........................................... -20 2.5 Light Microscopy .............................................. -21 CHAPTER 3: SYSTEMATICS ............................................. -22 3.1Morpholo gy .................................................... 22 3.1.1 General Architecture .................................... -22 3.1.2 Vesicle Wall .......................................... -38 3.1.3 Vesicte Distortion ...................................... -31 3.1.3.1 Physical ....................................... 31 3.1.3.2 Chernical ...................................... -32 3.1 -3-3 c'Biologicai" .....................................33 3.2 Biological Affinities ............................................ -34 CHAPTER 4: SYSTEMATIC PAL,EONTOLOGY ............................. -42 4-1 Introduction .................................................... 42 4.2Descriptions ................................................... 46 4.3 Measurements ................................................. -47 4-4 Synonymy Lists ................................................ -48 4.5Taxonomy ..................................................... 51 Farnily Desmochitinidae ......................................... -51 Subfarnily Desmochitininae ..................................... 51 Genus Desmochitina ...................................... -51 Family Conochitinidae ...........................................-55 Subfamily Belonechitininae .................................... -55 Genus Belonechitina ...................................... 55 Subfamily Conochitininae ..................................... -57 Genus Conochitina ....................................... -57 Genus Rhabdochitina ...................................... 104 Subfamily Tanuchitininae ..................................... 113 Genus Laufeldochitina .................................. .. 113 GenusTanuchitina ........................................ 115 Subfamily Eremochitininae .................................... 118 Genus Eremochitina .......................................118 Family Lagenochitinidae ......................................... 120 Subfarniiy Lagenochitininae ................................... 120 Genus Amphorachitina .................................... 120 Genus Lagenochitina ..................................... 123 Subfamily Cyathochitininae ................................... 152 Genus Cyathochitina ...................................... 152 CHAPTER 5: BIOSTRATIGRAPHY ....................................... 160 5.1 Previous Research .............................................. 160 5.2 Chitinozoan Assemblages ........................................ 162 5.2.1Tremadoc .............................................. 163 5.2.2Arenig ............................................... 164 5.3 Chitinozoan Zonation ........................................... 168 5.3.1 Arnphorachifina con~findasZone .......................... 169 5-3-2 Conochitina symmetrica Zone ............................. 170 5.3 -3 Lagenochitina esthonica / Conochirina raymondi Zone ......... 171 5.3.4 Conochitina langei / Conochitina brevis Zone ................ 174 5 3.5 Cyathochitina dispar Zone ................................ 175 5.3 -6 Laufeldochitina spZone .................................. 176 5 -4 Supplementary Note ...........................................-176 CONCLUSIONS ......................................................... 187 REFERENCESCITED .................................................... 189 APPENDICES ......................................................... 216 Appendix I - Plates .............................................. -216 ILLUSTRATIONS List of Text-Figures Page 1.1 Simplified geological map of the Humber (tectonostratigraphic) Zove of western Newfoundand showing location of study area .................... -5 1.2 Regional map of the distribution of the Cow Head Group and the location of sarnple sites ....................................................-6 1.3 Stratigraphie nomenclature and relationships of the units within the Cow HeadGroup ....................................................... 9 1.4 Depositiond mode1 showing the Cow Head Group formed as a sediment apron at the base of an