High-Precision ID-TIMS U-Pb Zircon Geochronology of Three Cenomanian Bentonites from the Western Canada Foreland Basin

The Western Canada foreland basin contains a rich record of Upper Cretaceous marine | and tectonic change, yet is sparse in biostratigraphically useful fauna that permit | continental and global correlation. However, numerous extensive bentonites have been 1 mapped in Cenomanian strata and traced into the U.S. portion of the basin where relationships to globally correlated ammonite zones can be determined. The X, A-X and Bighorn River bentonites provide important calibration points for the Cenomanian Stage. Single zircon crystals from these bentonites were chemically-abraded and dated using high-precision U-Pb ID-TIMS geochronology techniques. The Pb/ U weighted-mean ages are: 95.87±0.10 Ma for the X-bentonite, 95.67±0.15 Ma for the A-X bentonite, and 94.29±0.13 Ma for the Bighorn River Bentonite (2a confidence level). These new ages establish a more precise maximum age for the Cenomanian/Turonian boundary and allow for more accurate measurements of the timing and rates of Cenomanian tectonic and eustatic activity in western North America.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Geology

Year dc:date.issued

2009

Author dc:creator

• Barker, Ivan R.

Advisors dc:contributor.advisor

• Moser, Desmond
• Plint, Guy

• U-Pb Isotope Geochronology
• Tephrochronology
• Upper-Cretaceous
• Cenomanian
• ID-TIMS
• Zircon
• Bentonite
• Western Canada Foreland Basin
• Stratigraphy
• Blackstone Formation
• Dunvegan Formation
• Eustasy
• Tectonics

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/19317

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/19317