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 40 Ar/39 Ar 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.