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The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after creta, the Latin word for the white limestone known as chalk.
The Maastrichtian (/ m ɑː ˈ s t r ɪ k t i ə n / mahss-TRIK-tee-ən) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from .
The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains: An Integrated Continental Record of the End of the Cretaceous. Geological Society of America. pp. 145– 167. ISBN 978-0-8137-2361-7. Varricchio, D.J (2001). "Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana". In Carpenter, Kenneth (ed.).
At the beginning of the Late Cretaceous, around 100 million years ago, deposition changed to that of chalk, with the deposition of the Chalk Group continuing until the end of the Cretaceous. Chalk was deposited over much of Great Britain, now notably exposed at the White Cliffs of Dover and the Seven Sisters , and also forming Salisbury Plain .
The Cretaceous is characterized by warm global temperatures caused by the high amounts of carbon dioxide and possibly methane greenhouse gases in the atmosphere. This caused a lack of permanent ice coverage in the polar regions, though the carbon dioxide level dropped between 115 and 66 million years ago (mya), possibly allowing some permanent ice cover.
The first expansion was designed by BCW Architects, and was completed in 2003; while the second expansion was designed by Kasian Architecture, and was completed in 2019. The museum's personal collection includes over 160,000 cataloged fossils, consisting of over 350 holotypes , providing the museum with the largest collection of fossils in Canada.
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada [2] to New Mexico. The Pierre Shale was described by Meek and Hayden in 1862 in the Proceedings of the Academy of Sciences (Philadelphia).
The Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series. In older literature, the Cretaceous is sometimes divided into three series: Neocomian (lower/early), Gallic (middle) and Senonian (upper/late). A subdivision into 12 stages, all originating from European stratigraphy, is now used worldwide. In ...