A Mesozoic time scale

Abstract

We present an integrated geomagnetic polarity and stratigraphic time scale for the Triassic, Jurassic, and Cretaceous periods of the Mesozoic Era, with age estimates and uncertainty limits for stage boundaries. The time scale uses a suite of 324 radiometric dates, including high‐resolution 40Ar/39Ar age estimates. This framework involves the observed ties between (1) radiometric dates, biozones, and stage boundaries, and (2) between biozones and magnetic reversals on the seafloor and in sediments. Interpolation techniques include maximum likelihood estimation, smoothing cubic spline fitting, and magnetochronology. The age estimates for the 31 stage boundaries (in mega‐annum) with uncertainty (millions of years) to 2 standard deviations, and the duration of the preceding stages (in parentheses) are Maastrichtian/Danian (Cretaceous/‐Cenozoic) is 65.0±0.1 Ma (6.3 m.y.), Campanian/Maastrichtian is 71.3±0.5 Ma (12.2 m.y.), Santonian/Campanian is 83.5±0.5 Ma (2.3 m.y.), Coniacian/Santonian is 85.8±0.5 Ma (3.2 m.y.), Turonian/Coniacian is 89.0±0.5 Ma (4.5 m.y.), Cenomanian/Turonian is 93.5±0.2 Ma (5.4 m.y.), Albian/Cenomanian is 98.9±0.6 Ma (13.3 m.y.), Aptian/Albian is 112.2±1.1 Ma (8.8 m.y.), Barremian/Aptian is 121.0±1.4 Ma (6.0 m.y.), Hauterivian/Barremian is 127.0±1.6 Ma (5.0 m.y.), Valanginian/Hauterivian is 132.0±1.9 Ma (5.0 m.y.), Berriasian/Valanginian is 137.0±2.2 Ma (7.2 m.y.), Tithonian/Berriasian (Jurassic/Cretaceous) is 144.2±2.6 Ma (6.5 m.y.), Kimmeridgian/Tithonian is 150.7±3.0 Ma (3.4 m.y.), Oxfordian/Kimmeridgian is 154.1±3.2 Ma (5.3 m.y.), Callovian/Oxfordian is 159.4±3.6 Ma (5.0 m.y.), Bathonian/Callovian is 164.4±3.8 Ma (4.8 m.y.), Bajocian/Bathonian is 169.2±4.0 Ma (7.3 m.y.), Aalenian/Bajocian is 176.5±4.0 Ma (3.6 m.y.), Toarcian/Aalenian is 180.1±4.0 Ma (9.5 m.y.), Sinemurian/Pliensbachian is 195.3±3.9 Ma (6.6 m.y.), Hettangian/Sinemurian is 201.9±3.9 Ma (3.8 m.y.), Rhaetian/Hettangian (Triassic/Jurassic) is 205.7±4.0 Ma (3.9 m.y.), Norian/Rhaetian is 209.6±4.1 Ma (11.1 m.y.), Carnian/Norian is 220.7±4.4 Ma (6.7 m.y.), Ladinian/Carnian is 227.4±4.5 Ma (6.9 m.y.), Anisian/Ladinian is 234.3±4.6 Ma (7.4 m.y.), Olenekian/Anisian is 241.7±4.7 Ma (3.1 m.y.), Induan/Olenekian is 244.8±4.8 Ma (3.4 m.y.), Tatarian/Induan (Permian/Triassic) is 248.2±4.8 Ma. The uncertainty in the relative duration of each individual stage is much less than the uncertainties on the ages of the stage boundaries.

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set

“…Their new model interprets the spreading rate to be about 4.0 cm a )1 from the onset of spreading at about 130 Ma (time scale of Gradstein et al, 1994) to chron M4 (126.7 Ma) and then decreased to about 1.6 cm a )1 until spreading in the Enderby Basin ceased at about 124 Ma. At this time, a spreading ridge jump to the east Indian margin transferred the Elan Bank microcontinent to the Antarctic Plate.…”

Late Campanian–Maastrichtian foraminifera from the Simsima Formation on the western side of the Northern Oman Mountains

“…The lower boundary is indicated by the first appearance of Abathomphalus mayaroensis, at the base of chron 31 (Fig. 6), while the upper boundary is placed at the last Gradstein et al, 1994; palaeomagnetic polarities after Gradstein et al, 1994, andPremoli Silva &Sliter, 1994). 4, Bolivina incrassata gigantae, sample 10.…”

Deep-sea pre-glacial to glacial sedimentation in the Weddell Sea and southern Scotia Sea from a cross-basin seismic transect

“…The following seismic tie lines were Timescale: Chron and Age (this study) taken from Gradstein et al, 2004. Ages appended with old (o), middle (m) and young (y); Chron-L and Age-L (literature) from: C5n to C33r, Cande and Kent, 1995;C34 to E, Barker, 2001C34 to E, Barker, , 1994M0 to M17, Kent and Gradstein 1986;Gradstein et al, 1994. References: 1 Maldonado et al, 2007;2 Bohoyo et al, 2002;3 Eagles and Livermore, 2002;4 Lodolo et al, 1998;5 Kovacs et al, 2002;6 Ghidella et al, 2002;7 Nankivell, 1997;8 LaBrecque and 9 König and Jokat, 2006.…”