K/Ar Age of Lower–Upper Cretaceous Boundary at Orphan Knoll (Labrador Sea)

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Hinte, J. E. Van, Adams, J. A. S., Perry, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1975
• Subjects: General Earth and Planetary Sciences; Orphan Knoll; Labrador Sea
• Online Access: http://dx.doi.org/10.1139/e75-135; http://www.nrcresearchpress.com/doi/pdf/10.1139/e75-135

The Albian–Cenomanian of Orphan Knoll yielded unrecrystallized, unheated, autochthonous glauconite. K/Ar ages for the Lower Cenomanian samples are 100, 91, and 105 Ma (average 99), and the K/Ar age for one Upper Albian (Vraconian) sample is 96 Ma. The non-sequential results do not allow for great confidence in a precise boundary age. However, the data can be read to support the widely used assumption of −100 Ma as the age for the Albian-Cenomanian = Early-Late Cretaceous boundary.