T240 Excursions, Extinctions, and Environmental Change: New Advances in Geochemical Tools Linked to Critical Intervals of Environmental and Biotic Change in Earth History (Posters)

Tuesday, 27 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

MICROFACIES AND TRACE ELEMENT VARIATION ACROSS THE FRASNIAN PUNCTATA EVENT WITHIN THE BEAR BILTMORE DRILL CORE (ALBERTA, CANADA)

Paper number: T240-12
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Late Devonian oxygen isotope records show an increase in global sea surface temperature by as much as 9°C over the Frasnian stage (382.7-372.7 Ma), coincident with deposition of regional black shale horizons and global perturbation of the carbon isotope record. Previous studies of Devonian strata within the Western Canadian Sedimentary Basin have shown that pulses of terrestrial input during the mid-Frasnian punctata event are associated with increases in primary productivity and suboxic to anoxic marine conditions.

This investigation focused on understanding variations in sedimentation and ocean chemistry over 150ft of a single Frasnian section from northeastern Alberta, the Bear Biltmore drill core (7-11-87-17W4). Unlike previously-studied Frasnian sections from western Canada, samples from the Bear Biltmore core provide insight into more proximal reef to lower slope environments. 196 samples from 150ft of the core cover the middle to upper Frasnian within the Duvernay and Cooking Lake formations, including the globally recognized punctata carbon isotope excursion.

Initial results of microfacies work show a succession through the punctata interval from reef-derived bioclastic and intraclastic floatstones to a microbially-influenced shelf environment, followed by rapid transgression and transition into a fine-grained carbonate shelf environment. Results from x-ray fluorescence spectrometry of major, minor and trace elements over the study interval are currently undergoing data analysis. Taken together, microfacies and trace element variation will provide insight into the punctata isotope excursion as well as environmental change over the middle Frasnian.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-284521

© Copyright 2016 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.