Prairie Bluff Chalk

Prairie Bluff Chalk
Stratigraphic range: Cretaceous
Prairie Bluff Chalk Formation (Starkville, Mississippi)
TypeFormation
Unit ofSelma Group[1]
Lithology
PrimaryChalk
Location
Region Alabama and  Mississippi[1]
Country USA

The Prairie Bluff Chalk is a geologic formation in Alabama and Mississippi. It preserves fossils dating back to the Cretaceous period.[2][3]

The chalk was formed by marine sediments deposited along the eastern edge of the Mississippi embayment during the Maastrichtian stage of the Late Cretaceous. It is a unit of the Selma Group and marks the end of the Cretaceous in Alabama. Evidence has been found within the formation at Braggs, Moscow, and Millers Ferry in Alabama indicating an instantaneous to brief erosional event, most likely a tsunami, at the Cretaceous–Paleogene boundary (K–T boundary). It is hypothesized that this event, along with faulting and liquification of the Prairie Bluff Chalk, is related to the meteorite impact at the Chicxulub crater site, directly south, across the Gulf of Mexico, from the formation.[4]

  1. ^ a b "Geolex — Unit Summary: Prairie Bluff Chalk". United States Geological Survey. Retrieved 14 November 2019.
  2. ^ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
  3. ^ "Selma Group; Prairie Bluff Chalk (ALKpb;1)". mrdata.usgs.gov. Retrieved 2018-06-08.
  4. ^ Ryder, Graham (1996). The Cretaceous-Tertiary Event and Other Catastrophes in Earth History. Boulder, Colorado: Geological Society of America. pp. 271–273. ISBN 0-8137-2307-8.