- Usage in publication:
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- Cretaceous Period*
- Modifications:
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- Geochronologic dating
- Overview
Summary:
A new database is created using 40Ar/39Ar laser fusion geochronometry on sanidine from bentonites interbedded with fossiliferous marine sediments. Coupling the new geochronometry with an improved ammonite biozonation allows a new time scale to be compiled. The resulting ages for Cretaceous boundaries are as follows: Paleocene-Maastrichtian (Tertiary-Cretaceous) 65.4 +/-0.1 Ma Maastrichtian-Campanian 71.3 +/-0.5 Ma Campanian-Santonian 83.5 +/-0.5 Ma Santonian-Coniacian 86.3 +/-0.5 Ma Coniacian-Turonian 88.7 +/-0.5 Ma Turonian-Cenomanian 93.3 +/-0.2 Ma Cenomanian-Albian 98.5 +/-0.5 Ma Albian-Aptian 112 +/-1 Ma Aptian-Barremian 121 Ma Barremian-Hauterivian 127 Ma Hauterivian-Valanginian 130 Ma Valanginian-Berriasian 135 Ma Berriasian-Tithonian (Cretaceous-Jurassic) 142 Ma
Source: GNU records (USGS DDS-6; Denver GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).