Sedimentological and Ichnological Dynamics of the Early Cambrian Mount Clark Formation, Northwest Territories, Canada

  • Author / Creator
    Herbers, David S
  • The early Cambrian Mount Clark Formation of the Northwest Territories comprises marginal marine to marine siliciclastic sediments deposited in an incipient rift basin on the margin of Laurentia. Within core and outcrop datasets the preserved record of sedimentation represents complex and highly variable lateral to vertical architecture. As a result of recording early Cambrian (Series 2, Stage 3: Bonnia-Olenellus trilobites) the Mount Clark Formation represents a rare opportunity to study marine biological interactions at the very onset of the Cambrian Explosion. To achieve this objective, high resolution sedimentological ichnological data was recorded from a six core database within the Colville Hills in addition to the field description of 8 outcrops in the Mackenzie Mountains over the course of two field seasons. Eight distinct lithofacies (F1-F8) were identified in the Colville Hills recording offshore to continental deposition along a strongly storm-influence shoreface succession. Three distinct facies associations (FA1-3) were identified within the Mackenzie Mountains recording shoreface (FA1), deltaic (FA2), and tidal embayment (FA3) sedimentation. Shoreface sedimentation (FA1) ranged from strongly storm-influenced to storm-affected lower shoreface to foreshore environments and were identified on the presence of robust and diverse trace fossil assemblages. Deltaic sedimentation (FA2) ranged from strongly storm-influenced to storm-affected prodelta to upper delta-front environments and were identified on the basis of stressed trace fossil assemblages recording decreasing ichnofossil size, diversity, and abundance in collaboration with more immature lithologies. Tidal compound dune sedimentation (FA3) ranged from embayment margin to the core of a compound dune field. Shoreface trace fossil assemblages within both study areas were found to have higher degrees of diversity, abundance, and complexity than previously identified early Cambrian trace fossil assemblages. It is interpreted that the Mount Clark Formation represents the earliest known radiation into these characteristic ethologies predating the famous and complex body fossils within the Burgess Shale. This body of work seeks to highlight a poorly understood region of Canada’s north, recording deposition at a time when complex life was first inhabiting Earth’s primordial oceans.

  • Subjects / Keywords
  • Graduation date
    Spring 2017
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.