Prairie Bluff Chalk

{{short description|Formation in Alabama and Mississippi, United States}} {{more citations needed|date=October 2017}} {{Infobox rockunit | name = Prairie Bluff Chalk | image = Prairie Bluff Chalk Formation Starkville MS 052510.JPG | caption = Prairie Bluff Chalk Formation (Starkville, Mississippi) | type = [[Formation (stratigraphy)|Formation]] | age = [[Cretaceous]] | period = Cretaceous | prilithology = [[Chalk]] | otherlithology = | namedfor = | namedby = | region = [[Alabama]], [[Mississippi]]<ref name=geolex /> | country = [[United States]] | coordinates = | unitof = [[Selma Group]]<ref name=geolex>{{cite web |url=https://ngmdb.usgs.gov/Geolex/Units/PrairieBluff_3405.html |title= Geolex — Unit Summary: Prairie Bluff Chalk|author= |date= |website= |publisher=[[United States Geological Survey]] |access-date=14 November 2019 |quote=}}</ref> | subunits = | underlies = | overlies = | thickness = | extent = | area = | map = | map_caption = }}

The '''Prairie Bluff Chalk''' is a [[Formation (geology)|geologic formation]] in [[Alabama]] and [[Mississippi]]. It preserves [[fossils]] dating back to the [[Cretaceous]] [[Period (geology)|period]].<ref>{{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}}</ref><ref>{{Cite web|url=https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=ALKpb;1|title=Selma Group; Prairie Bluff Chalk (ALKpb;1)|website=mrdata.usgs.gov|access-date=2018-06-08}}</ref>

The [[chalk]] was formed by [[pelagic sediments|marine sediments]] deposited along the eastern edge of the [[Mississippi embayment]] during the [[Maastrichtian (geological period)|Maastrichtian]] [[Stage (stratigraphy)|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, Marengo County, Alabama|Moscow]], and [[Millers Ferry, Alabama|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 [[Fault (geology)|faulting]] and [[Soil liquefaction|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.<ref name="KTEVENT">{{cite book |title=The Cretaceous-Tertiary Event and Other Catastrophes in Earth History |last=Ryder |first=Graham |year=1996 |publisher=Geological Society of America |location=Boulder, Colorado |isbn=0-8137-2307-8 |pages=271–273 |url=https://books.google.com/books?id=kAup0TOL09gC&dq=%22Prairie+Bluff+Chalk%22&pg=PA272 }}</ref>

==See also== {{Portal|Paleontology}} *[[List of fossil sites]] **[[List of fossiliferous stratigraphic units in Alabama]] **[[List of fossiliferous stratigraphic units in Mississippi]] * [[Paleontology in Alabama]] * [[Paleontology in Mississippi]]

==References== {{reflist}}

==External links== *[http://www.foraminifera.eu/starkville.html Microfossils: Images of Foraminifera from the Prairie Bluff FM at Starkville, MS from www.foraminifera.eu]

[[Category:Cretaceous Alabama]] [[Category:Cretaceous Mississippi]] [[Category:Geologic formations of Alabama]] [[Category:Chalk formations]] [[Category:Mississippi embayment]] [[Category:Maastrichtian Stage of North America]] [[Category:Geologic formations of Mississippi]]