The Geobiology of the Paleoproterozoic Belcher Group, Nunavut, Canada Masters Thesis Submitted to the College of Graduate and Postdoctoral Studies In Partial Fulfillment of the Requirements For the Degree of Master of Science In the Department of Geological Sciences University of Saskatchewan Saskatoon, Saskatchewan, Canada By Zachary Stephen William Morrow-Pollock © Copyright Zachary Stephen William Morrow-Pollock, December 2020. All rights reserved. Unless otherwise noted, copyright of the material in this thesis belongs to the author. PERMISSION TO USE In presenting this thesis/dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis/dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis/dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis/dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis/dissertation. DISCLAIMER Reference in this thesis/dissertation to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the University of Saskatchewan. The views and opinions of the author expressed herein do not state or reflect those of the University of Saskatchewan and shall not be used for advertising or product endorsement purposes. Requests for permission to copy or to make other uses of materials in this thesis/dissertation in whole or part should be addressed to: Dr. Samuel Butler, Department Head of Geological Sciences 114 Science Place University of Saskatchewan Saskatoon, Saskatchewan S7N 5E2 Canada OR Dean Deborah Burshtyn College of Graduate and Postdoctoral Studies University of Saskatchewan 116 Thorvaldson Building, 110 Science Place Saskatoon, Saskatchewan S7N 5C9 Canada i Abstract The Belcher Group Microbiota (BGM) are a collection of microbial organisms from the Paleoproterozoic (~2.0 to 1.8 Ga) Belcher Group from the Belcher Islands, Nunavut, Canada. The Belcher Group is exceptionally well-preserved, having avoided deep burial or strong deformation during the Trans-Hudson orogen. The 6-9 km thick Belcher Group includes a variety of shallow marine depositional environments, two distinct periods of volcanism, and a prograding submarine fan system. The rock types range from dolomitic carbonate platforms to flood and pillow basalts to granular iron formations to sandstones. The BGM are found primarily in chert-replaced stromatolitic layers in dolostones of the lower and middle Belcher Group, including the Kasegalik and McLeary formations, and show dominantly filamentous (i.e., segmented) and coccoid (i.e., spherical) morphologies. The Belcher Group was first studied over 100 years ago, with the focus initially on the iron formation rocks and stromatolitic dolostones. Research on the putative microfossils and the geological history of the Belcher Group became the focus of later studies during the 1960s through the 1980s. The BGM were first described by Hans Hofmann as a collection of benthic prokaryotic organisms consisting of up to 24 taxa with filamentous and coccoid morphologies. However, due to degradation and diagenesis effects, Hofmann determined that the 24 different taxa could be as few as 10 distinctive taxa. The taxa of the BGM are contemporaneous with the Gunflint Microbiota but share more similarities with the microbiota of the Bitter Springs Formation. The main objective of this thesis is to confirm the biogenicity of the BGM. Previous characterization of the BGM utilized transmitted light microscopy. This thesis further investigates the BGM by utilizing other methods including Raman spectroscopy, X-ray photoelectron spectroscopy, and both electron microprobe and scanning electron microscopy, in addition to petrography and field work. This work shows that the microbiota likely represent cyanobacteria that built stromatolite structures in peritidal carbonate rocks, consistent with previous work. New data from Raman and XPS show that organic carbon is present in the spherules from the Kipalu Formation, which suggests microbiota could have facilitated the deposition of the granular iron formation. Pseudofossils were discovered during the re- examination of McLeary Formation samples, which show that abiotic structures exist as well as biogenic ones. Nevertheless, data from Raman and XPS show evidence for organic matter preservation in the Belcher Group rocks associated with stromatolites and microbial mats. The discovery of pseudofossils does not invalidate the interpretation of the BGM as cyanobacteria, however it shows that extraordinary preservation of the BGM is not universal. ii Acknowledgements I would like to acknowledge the guidance from my supervisor Camille Partin and my Advisory Committee members: Joyce McBeth and M. Gabriela Mángano. I want to also acknowledge the financial assistance I received from my supervisor’s Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (RGPIN-2016-04501) as well as Polar Knowledge Canada’s Northern Scientific Training Program (NSTP). Lastly, I want to acknowledge Brayden McDonald, Malcolm Hodgskiss, Blaine Novakovski, Tim Prokopiuk, Tom Bonli, and finally Ramaswami Sammynaiken and his people at the Saskatchewan Structural Sciences Centre for their support in fieldwork and data collection throughout the course of this project. iii Table of Contents: PERMISSION TO USE ................................................................................................................................. i Abstract ........................................................................................................................................................ ii Acknowledgements ...................................................................................................................................... iii Table of Contents: ........................................................................................................................................ iv List of Tables ............................................................................................................................................... vi List of Figures ............................................................................................................................................ viii Chapter 1. Introduction .............................................................................................................................. 1 1.1 Research Objectives and Hypothesis .................................................................................................. 5 1.2 Research Scope and Problem .............................................................................................................. 5 Chapter 2. A Brief History on the Evolution of Life ................................................................................ 7 2.1 Beginnings of Prokaryotic Organisms ................................................................................................ 7 2.2 Developments during the Archean and Paleoproterozoic ................................................................. 10 2.3 Emergence of Eukaryotes ................................................................................................................. 16 Chapter 3. Geological Setting of the Belcher Group ............................................................................. 22 3.1 Regional Tectonic History ................................................................................................................ 22 3.2 Stratigraphy and formations of interest ............................................................................................. 27 3.2.1 Kasegalik Formation .................................................................................................................. 28 3.2.2 McLeary Formation ................................................................................................................... 29 3.2.3 Kipalu Formation ....................................................................................................................... 31 3.3 Local Depositional Phases ................................................................................................................ 33 Chapter 4. Previous Characterization of the Belcher Group Microbiota ........................................... 37 4.1 Stromatolite Morphology .................................................................................................................. 37 4.1.1 Kasegalik Formation .................................................................................................................. 37 4.1.2 McLeary Formation ................................................................................................................... 38 4.1.3 Mavor Formation ......................................................................................................................