Cenomanian

Cenomanian
100.5 – 93.9 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the Planktonic Foraminifer Rotalipora globotruncanoides
Lower boundary GSSPMont Risoux, Hautes-Alpes, France
44°23′33″N 5°30′43″E / 44.3925°N 5.5119°E / 44.3925; 5.5119
Lower GSSP ratified2002[2]
Upper boundary definitionFAD of the Ammonite Watinoceras devonense
Upper boundary GSSPRock Canyon, Colorado, US
38°16′56″N 104°43′39″W / 38.2822°N 104.7275°W / 38.2822; -104.7275
Upper GSSP ratifiedSeptember 2003[3]

The Cenomanian is in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series.[4] An age is a unit of geochronology; it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name.

As a unit of geologic time measure, the Cenomanian Age spans the time between[5] 100.5 and 93.9 million years ago (Mya). In the geologic timescale, it is preceded by the Albian and is followed by the Turonian. The Upper Cenomanian starts around at 95 Mya.[citation needed]

The Cenomanian is coeval with the Woodbinian of the regional timescale of the Gulf of Mexico and the early part of the Eaglefordian of the regional timescale of the East Coast of the United States.

At the end of the Cenomanian, an anoxic event took place, called the Cenomanian-Turonian boundary event or the "Bonarelli event", that is associated with a minor extinction event for marine species.

Cenomanithrips, an extinct thrip of the Stenurothripidae family, was named after the Cenomanian, the age of the Myanmar amber in which it was discovered.[6]

  1. ^ International Commission on Stratigraphy. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ Kennedy, W.; Gale, A.; Lees, J.; Caron, M. (March 2004). "The Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France" (PDF). Episodes. 27: 21–32. doi:10.18814/epiiugs/2004/v27i1/003. Retrieved 13 December 2020.
  3. ^ Kennedy, W. J.; I. Walaszczyk; W. A. Cobban (2005). "The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, U.S.A." (PDF). Episodes. 28 (2): 93–104. doi:10.18814/epiiugs/2005/v28i2/003.
  4. ^ See for a detailed geologic timescale Gradstein et al. (2004)
  5. ^ "International Stratigraphic Chart v2021/05". Archived from the original on 2021-06-05. Retrieved 2021-07-29.
  6. ^ Tong T, Shih CK, Ren D (2019). "A new genus and species of Stenurothripidae (Insecta: Thysanoptera: Terebrantia) from mid-Cretaceous Myanmar amber". Cretaceous Research. 100: 184–191. Bibcode:2019CrRes.100..184T. doi:10.1016/j.cretres.2019.03.005.{{cite journal}}: CS1 maint: multiple names: authors list (link)