|2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)|
|Paper No. 341-2|
|Presentation Time: 1:15 PM-1:30 PM|
NEW CONODONT FAUNAL ASSEMBLAGES FROM THE ANISIAN OF BRITISH COLUMBIA AND THEIR USE IN LOCAL STRATIGRAPHIC CORRELATION
GOLDING, Martyn, Earth, Ocean and Atmospheric Science, University of British Columbia, 2020-2207 Main Mall, Vancouver, BC V6T 1Z4, Canada, firstname.lastname@example.org and ORCHARD, Michael J., Geological Survey of Canada, 1500 - 605 Robson Street, Vancouver, BC V6B 5J3, Canada|
Conodonts and ammonoids are the two most useful and widely used taxonomic groups for biostratigraphy in the marine Triassic of North America. Both groups have a well-established zonation throughout the Triassic. However, during the Anisian stage (Middle Triassic) in North America, the resolution of the current conodont zonation is not as precise as that of the ammonoids. Although ammonoids are often abundant in some outcrop sections, conodonts are far more ubiquitous, and the lack of resolution in their zonation during this stage affects the precision and accuracy of correlation between sections. This lack of precision is particularly problematic when attempting to correlate between outcrop sections and subsurface drill core, as ammonoids are virtually absent in the latter.
The lack of resolution in the conodont zonation is due in part to the broad taxonomic concepts that have previously been applied to conodont species from the Anisian of North America; the majority of specimens recovered from rocks of this age have been assigned to one of only six species belonging to either Neogondolella or Paragondolella. This has led to the obscuring of morphological variability, some of which is now thought to be stratigraphically significant.
Examination of new and existing collections from outcrop sections and subsurface drill core in northeastern British Columbia has allowed the recognition of 10 new species of conodonts belonging to Neogondolella, as well as 19 new morphotypes of species of Neogondolella and Paragondolella. This represents a dramatic increase in taxa from the six species that have commonly been recognized in the past. These new species and morphotypes allow the delineation of eleven new, informal conodont faunal assemblages that enable correlation between outcrop sections and subsurface drill core across British Columbia. These assemblages have not yet been formalized as biozones, pending further work on existing material to constrain their stratigraphical and geographical extent. At present, these assemblages appear to be applicable at a local scale, and further work on Anisian faunas from the Canadian Arctic and Nevada is underway to determine if they can be recognised at a regional scale as well.
2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)
General Information for this Meeting
|Session No. 341|
Conodonts as Stratigraphic and Paleoclimatic Tools
Vancouver Convention Centre-West: 220
1:00 PM-5:00 PM, Wednesday, 22 October 2014
© Copyright 2014 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.