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Revision of the position of the Ordovician-Silurian boundary in southern Ontario: regional chronostratigraphic implications of delta C-13 chemostratigraphy of the Manitoulin Formation and associated strata

Bergstrom, Stig M.; Kleffner, Mark; Schmitz, Birger LU and Cramer, Bradley D. (2011) In Canadian Journal of Earth Sciences 48(11). p.1447-1470
Abstract
delta C-13 values of 142 samples from the Manitoulin Formation and subjacent strata collected from 14 exposures and two drill-cores on Manitoulin Island, Bruce Peninsula, and the region south of Georgian Bay suggest that the Manitoulin Formation is latest Ordovician (Hirnantian) rather than earliest Silurian in age. A delta C-13 excursion identified as the Hirnantian isotope carbon excursion (HICE), which has a magnitude of nearly 2.5 parts per thousand above baseline values, is present in an interval from the upper Queenston Formation to the lower to middle part of the Manitoulin Formation in most of Bruce Peninsula and in the area south of Georgian Bay, whereas on Manitoulin Island the RICE appears to be absent. This indicates that a... (More)
delta C-13 values of 142 samples from the Manitoulin Formation and subjacent strata collected from 14 exposures and two drill-cores on Manitoulin Island, Bruce Peninsula, and the region south of Georgian Bay suggest that the Manitoulin Formation is latest Ordovician (Hirnantian) rather than earliest Silurian in age. A delta C-13 excursion identified as the Hirnantian isotope carbon excursion (HICE), which has a magnitude of nearly 2.5 parts per thousand above baseline values, is present in an interval from the upper Queenston Formation to the lower to middle part of the Manitoulin Formation in most of Bruce Peninsula and in the area south of Georgian Bay, whereas on Manitoulin Island the RICE appears to be absent. This indicates that a significant part of the Manitoulin Formation is older on the Bruce Peninsula and in its adjacent region than on Manitoulin Island. The chemostratigraphically based conclusions are consistent with biostratigraphic data from conodonts and brachiopods. The Hirnantian delta C-13 curve from Anticosti Island, Quebec is closely similar to those of southern Ontario. Traditionally, the Ordovician-Silurian boundary has been placed at the base of the Manitoulin Formation, but the new results suggest that it is more likely to be at, or near, the base of the overlying Cabot Head Formation. These new results have major implications For the interpretation of the geologic history and marine depositional patterns of the latest Ordovician of a large part of the North American Midcontinent. (Less)
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organization
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Contribution to journal
publication status
published
subject
in
Canadian Journal of Earth Sciences
volume
48
issue
11
pages
1447 - 1470
publisher
NRC Research Press
external identifiers
  • wos:000296988000001
  • scopus:80055076660
ISSN
0008-4077
DOI
10.1139/E11-039
language
English
LU publication?
yes
id
3a24e5fe-57e5-484a-a558-235c45109adc (old id 2252958)
date added to LUP
2011-12-22 09:15:43
date last changed
2017-11-12 03:46:16
@article{3a24e5fe-57e5-484a-a558-235c45109adc,
  abstract     = {delta C-13 values of 142 samples from the Manitoulin Formation and subjacent strata collected from 14 exposures and two drill-cores on Manitoulin Island, Bruce Peninsula, and the region south of Georgian Bay suggest that the Manitoulin Formation is latest Ordovician (Hirnantian) rather than earliest Silurian in age. A delta C-13 excursion identified as the Hirnantian isotope carbon excursion (HICE), which has a magnitude of nearly 2.5 parts per thousand above baseline values, is present in an interval from the upper Queenston Formation to the lower to middle part of the Manitoulin Formation in most of Bruce Peninsula and in the area south of Georgian Bay, whereas on Manitoulin Island the RICE appears to be absent. This indicates that a significant part of the Manitoulin Formation is older on the Bruce Peninsula and in its adjacent region than on Manitoulin Island. The chemostratigraphically based conclusions are consistent with biostratigraphic data from conodonts and brachiopods. The Hirnantian delta C-13 curve from Anticosti Island, Quebec is closely similar to those of southern Ontario. Traditionally, the Ordovician-Silurian boundary has been placed at the base of the Manitoulin Formation, but the new results suggest that it is more likely to be at, or near, the base of the overlying Cabot Head Formation. These new results have major implications For the interpretation of the geologic history and marine depositional patterns of the latest Ordovician of a large part of the North American Midcontinent.},
  author       = {Bergstrom, Stig M. and Kleffner, Mark and Schmitz, Birger and Cramer, Bradley D.},
  issn         = {0008-4077},
  language     = {eng},
  number       = {11},
  pages        = {1447--1470},
  publisher    = {NRC Research Press},
  series       = {Canadian Journal of Earth Sciences},
  title        = {Revision of the position of the Ordovician-Silurian boundary in southern Ontario: regional chronostratigraphic implications of delta C-13 chemostratigraphy of the Manitoulin Formation and associated strata},
  url          = {http://dx.doi.org/10.1139/E11-039},
  volume       = {48},
  year         = {2011},
}