Journal
SEDIMENTARY GEOLOGY
Volume 281, Issue -, Pages 50-58Publisher
ELSEVIER
DOI: 10.1016/j.sedgeo.2012.08.004
Keywords
Cretaceous; Forebulge; Carbon isotopes; Western Interior Sea; Oceanic anoxic events; extinctions
Categories
Funding
- Natural Science and Engineering Research Council of Canada
- German Science Foundation [HE 3521/6]
- Biodiversity and Climate Research Centre (BIK-F)
- Krupp-Stiftung
- Canada Research Chair
Ask authors/readers for more resources
The forebulge region of the Cretaceous Canadian Western Interior Sea (CWIS) was susceptible to subaerial exposure and marine erosion during sea level lowstands. The middle Albian to Santonian record as cored at Cold Lake, east-central Alberta, Canada documents numerous disconformities that are expressed in bioclastic concentration horizons and faunal extinctions and turnovers. Detailed comparison between a newly established delta C-13(org.) record measured on bulk sediment at Cold Lake and a combined delta C-13(carb.) reference curve based on the Cretaceous English chalk and SE France hemipelagic marlstones highlights missing positive and negative delta C-13 excursions at the CWIS forebulge and thus missing sections that precisely corroborate with sequence boundaries. Disconformable boundaries correlate closely with global sea-level lowstands as established for the Cretaceous North Atlantic suggesting a pronounced eustatic influence on the CWIS forebulge setting. Sequence boundaries occur in the uppermost Middle Albian, lowermost Upper Albian, Albian/Cenomanian boundary, Cenomanian/Turonian boundary, middle Turonian to lower Coniacian and uppermost Middle Santonian, each followed by a positive delta C-13 excursion. Oceanic anoxic events 1d, 2 and 3 are recognized and linked to major faunal and floral assemblage changes. Of these the Albian/Cenomanian biotic turnover is the most severe in the CWIS marked by the total loss of Albian benthic foraminifera species. Causes of this benthic extinction might be linked to a period of anoxia (OAE 1d) during the latest Albian followed by sea-level controlled basin restriction. (c) 2012 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available