Cenozoic Time Scale

A WORLD-WIDE CENOZOIC TIME SCALE

BOUNDARY TIME (in millions of years) CHRON

Pleistocene-Holocene Boundary 0.010 Ma ^a -

Pliocene-Pleistocene Boundary 1.79 Ma Bottom of C1r

Miocene-Pliocene Boundary 5.32 Ma C 3r

Middle Miocene-Late Miocene Boundary 11.2 Ma C 5r.2r

Early Miocene-Middle Miocene Boundary 16.40 Ma C 5Cn.2n

Oligocene-Miocene Boundary 23.80 Ma At the C6Cn.2n/r Boundary₍₀₎

Eocene-Oligocene Boundary 33.7 Ma Within(?) Chron C13r (still in some debate)

Paleocene-Eocene Boundary 54.8 Ma Within Chron C24r

Maastrichtian/Danian Boundary (Cret/Tertiary) 65.00+/- 0.04 Ma^b Occurs in the upper portion of C29r (approximately C29r.7)

BOUNDARY	TIME (in millions of years)	CHRON
Pleistocene-Holocene Boundary	0.010 Ma ^a	-
Pliocene-Pleistocene Boundary	1.79 Ma	Bottom of C1r
Miocene-Pliocene Boundary	5.32 Ma	C 3r
Middle Miocene-Late Miocene Boundary	11.2 Ma	C 5r.2r
Early Miocene-Middle Miocene Boundary	16.40 Ma	C 5Cn.2n
Oligocene-Miocene Boundary	23.80 Ma	At the C6Cn.2n/r Boundary₍₀₎
Eocene-Oligocene Boundary	33.7 Ma	Within(?) Chron C13r (still in some debate)
Paleocene-Eocene Boundary	54.8 Ma	Within Chron C24r
Maastrichtian/Danian Boundary (Cret/Tertiary)	65.00+/- 0.04 Ma^b	Occurs in the upper portion of C29r (approximately C29r.7)

COMMENTS ^a The Pleistocene-Holocene Boundary appears to be defined two different ways, depending on who you ask. The conventional definition is old, and arbitrarily places the Pleistocene-Holocene boundary at 10,000 years (a time-based boundary. There is no international stratotype for the Holocene).
In Europe, the tendency seems to be to use the Younger Dryas-Pre-Boreal transition as the boundary (end of Younger Dryas = 11,200 ya). Thanks to Rickard Toomey and John Van Couvering for the Pleistocene/Holocene information, which was provided in a 1997 public discussion on the Vertebrate Paleontology Mailing List (vrtpaleo@usc.edu).

^bGradstein et al. (1995:102). But Obradovich (1993) gives 65.4 +or- 0.1 Ma as the most accurate date obtained from the Western Interior Basin of North America.

References

Berggren, W. A., D.V. Kent, C.C. Swisher, and M. Aubry. 1995. A Revised Cenozoic Geochronology and Chronostratigraphy, pp. 129-212, IN Berggren, W. A., D.V. Kent, C.C., Swisher, M. Aubry, and J. Hardenbol (eds), Geochronology, Time Scales and Global Stratigraphic Correlation. SEPM Special Publication No. 54.

Gradstein, F.M., F.P. Agterberg, J.G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. Mesozoic timescale, pp. 95-126, IN Berggren, W. A., D.V. Kent, C.C., Swisher, M. Aubry, and J. Hardenbol (eds), Geochronology, Time Scales and Global Stratigraphic Correlation. SEPM Special Publication No. 54.

Kennett, J.P., and B.L. Ingram. 1995. A 20,000-year record of ocean circulation and climate change from the Santa Barbara basin. Nature, vol. 377:510-513.

Obradovich, J., 1993, A Cretaceous Time scale: IN Caldwell and Kauffman K (eds.), Evolution of the Western Interior Basin, Geological Association of Canada Special Paper 39, p. 379-396.

Prueher, L.M., and D.K. Rea. 1998. Rapid onset of glacial conditions in the subarctic North Pacific region at 2.67 Ma: Clues to causality. Geology, 26(11):1027-1030.

Hell Creek Life © 1997-2005 Phillip Bigelow