The Ecology, Neoichnology and Sedimentology of Siliciclastic Hardground Communities: Implications for Trypanites Assemblages in the Rock Record

  • Author / Creator
    Furlong, Carolyn Marie
  • The paleoecology of rocky substrates in the rock record is commonly interpreted based on ichnology (the Trypanites ichnofacies) and is frequently associated with a biotic assemblage with low diversity. However, analyses of two modern, siliclastic, intertidal hardground community at Lion Rock, located at Arcadia Beach State Park, Oregon, and Thomas Cove at Upper Economy, Nova Scotia (Bay of Fundy), reveal diverse communities of boring, encrusting and squatting/clinging organisms. Through observations and descriptions of organism distribution and abundance, up to 45 species of flora and fauna are reported to inhabit the study areas. At Lion Rock, organisms reside within five littoral zones (supra-, upper-, middle-, and lower littoral zones, and a newly established sublittoral zone) on the sea stack. Borings are produced by Adula californiensis, Hiatella arctica, Penitella penita, and Zirfaea pilsbryi and are identified as Gastrochaenolites-type traces. At Thomas Cove, organisms inhabit eleven depositional sub-environments and borings are formed by Petricola pholadiformis and Zirfaea pilsbryi, and are also identified as Gastrochaenolites-type traces. Within the two studied localities, substrate, sediment type and thickness, water presence during low tide and water velocity control boring location and abundance. It is likely that ancient Trypanites communities had considerably higher diversity and faunal abundance than their ichnological record indicates. Comparisons with modern assemblages are thus crucial in assessing these environments in ancient successions.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • 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.