|
Polarity
chron/subchron |
Normal polarity
interval (Ma) |
Epoch, stage
(approximate) |
Reference
|
Comments
|
|
|---|---|---|---|---|---|
|
Top
|
Bottom
|
||||
| C1n | 0.000 | 0.780 | Pleistocene | 1 | Brunhes (Chron C1r–Matuyama) |
| C1r.1n | 0.990 | 1.070 | Pleistocene | 1 | Jaramillo |
| C1r.2n | 1.201 | 1.211 | Pleistocene | 1 | Cobb Mountain |
| C2n | 1.770 | 1.950 | Pliocene, Piacenzian | 1 | Olduvai |
| C2r.1n | 2.140 | 2.150 | Pliocene, Piacenzian | Adjusted 5 | Reunion |
| C2An.1n | 2.581 | 3.040 | Pliocene, Piacenzian | 1, 2 | Gauss Normal (all Chron C2An); subdivided by brief reversed polarity intervals Kaena (Subchron 2An.1r) and Mammoth (Subchron 2An.2r) |
| C2An.2n | 3.110 | 3.220 | Pliocene, Piacenzian | 2 |
|
| C2An.3n | 3.330 | 3.580 | Pliocene, Piacenzian | 2 |
|
| C3n.1n | 4.180 | 4.290 | Pliocene, Zanclean | 2 | Cochiti Normal (in Gilbert Reversed, which spans Chrons C2Ar–C3r) |
| C3n.2n | 4.480 | 4.620 | Pliocene, Zanclean | 2 | Nunivak Normal |
| C3n.3n | 4.800 | 4.890 | Pliocene, Zanclean | 2 | Sidufjall Normal |
| C3n.4n | 4.980 | 5.230 | Pliocene, Zanclean | 2, 4 | Thvera Normal |
| C3An.1n | 5.875 | 6.122 | Miocene, Messinian | 4 | 5 has slightly different ages for the set calibrated by 4 |
| C3An.2n | 6.256 | 6.555 | Miocene, Messinian | 4 |
|
| C3Bn | 6.919 | 7.072 | Miocene, Messinian | 4 |
|
| C3Br.1n | 7.135 | 7.170 | Miocene, Tortonian | 4 |
|
| C3Br.2n | 7.341 | 7.375 | Miocene, Tortonian | 4 |
|
| C4n.1n | 7.406 | 7.533 | Miocene, Tortonian | 4 |
|
| C4n.2n | 7.618 | 8.027 | Miocene, Tortonian | 4 |
|
| C4r.1n | 8.174 | 8.205 | Miocene, Tortonian | 4 |
|
| C4An | 8.631 | 8.945 | Miocene, Tortonian | 4 |
|
| C4Ar.1n | 9.142 | 9.218 | Miocene, Tortonian | 4 |
|
| C4Ar.2n | 9.482 | 9.543 | Miocene, Tortonian | 4 |
|
| C5n.1n | 9.639 | 9.880 | Miocene, Tortonian | 4 |
|
| C5n.2n | 9.920 | 10.839 | Miocene, Tortonian | 4 |
|
| C5r.1n | 10.943 | 10.991 | Miocene, Tortonian | 4 |
|
| C5r.2n | 11.343 | 11.428 | Miocene, Serravalian | 4 |
|
| C5An.1n | 11.841 | 11.988 | Miocene, Serravalian | 4 |
|
| C5An.2n | 12.096 | 12.320 | Miocene, Serravalian | 4 |
|
| C5Ar.1n | 12.605 | 12.637 | Miocene, Serravalian | 4 |
|
| C5Ar.2n | 12.705 | 12.752 | Miocene, Serravalian | 4 |
|
| C5AAn | 12.929 | 13.083 | Miocene, Serravalian | 4 |
|
| C5ABn | 13.252 | 13.466 | Miocene, Serravalian | 4 |
|
| C5ACn | 13.666 | 14.053 | Miocene, Serravalian | 4 |
|
| C5ADn | 14.159 | 14.607 | Miocene, Serravalian | 4 |
|
| C5Bn.1n | 14.800 | 14.888 | Miocene, Langhian | 4, 5 | 14.8 Ma for base of Chron C5ADr is an age control point of 5 |
| C5Bn.2n | 15.034 | 15.155 | Miocene, Langhian | 5 |
|
| C5Cn.1n | 16.014 | 16.293 | Miocene, Langhian | 5 |
|
| C5Cn.2n | 16.327 | 16.488 | Miocene, Langhian | 5 |
|
| C5Cn.3n | 16.556 | 16.726 | Miocene, Burdigalian | 5 |
|
| C5Dn | 17.277 | 17.615 | Miocene, Burdigalian | 5 |
|
| C5En | 18.281 | 18.781 | Miocene, Burdigalian | 5 |
|
| C6n | 19.048 | 20.131 | Miocene, Burdigalian | 5 |
|
| C6An.1n | 20.518 | 20.725 | Miocene, Aquitanian | 5 |
|
| C6An.2n | 20.996 | 21.320 | Miocene, Aquitanian | 5 |
|
| C6AAn | 21.768 | 21.859 | Miocene, Aquitanian | 5 |
|
| C6AAr.1n | 22.151 | 22.248 | Miocene, Aquitanian | 5 |
|
| C6AAr.2n | 22.459 | 22.493 | Miocene, Aquitanian | 5 |
|
| C6Bn.1n | 22.588 | 22.750 | Miocene, Aquitanian | 5 |
|
| C6Bn.2n | 22.804 | 23.069 | Miocene, Aquitanian | 5 |
|
| C6Cn.1n | 23.353 | 23.535 | Miocene, Aquitanian | 5 |
|
| C6Cn.2n | 23.677 | 23.800 | Miocene, Aquitanian | 5 | 23.8 Ma (Eocene/Oligocene boundary) at base of Subchron C6Cn.2n is an age control point of 5 |
| C6Cn.3n | 23.999 | 24.118 | Oligocene, Chattian | 5 |
|
| C7n.1n | 24.730 | 24.781 | Oligocene, Chattian | 5 |
|
| C7n.2n | 24.835 | 25.183 | Oligocene, Chattian | 5 |
|
| C7An | 25.496 | 25.648 | Oligocene, Chattian | 5 |
|
| C8n.1n | 25.823 | 25.951 | Oligocene, Chattian | 5 |
|
| C8n.2n | 25.992 | 26.554 | Oligocene, Chattian | 5 |
|
| C9n | 27.027 | 27.972 | Oligocene, Chattian | 5 |
|
| C10n.1n | 28.283 | 28.512 | Oligocene, Chattian | 5 |
|
| C10n.2n | 28.578 | 28.745 | Oligocene, Rupelian | 5 |
|
| C11n.1n | 29.401 | 29.662 | Oligocene, Rupelian | 5 |
|
| C11n.2n | 29.765 | 30.098 | Oligocene, Rupelian | 5 |
|
| C12n | 30.479 | 30.939 | Oligocene, Rupelian | 5 |
|
| C13n | 33.058 | 33.545 | Oligocene, Rupelian | 5 | 33.7 Ma for Subchron C13r.85 is an age control point of 5 |
| C15n | 34.655 | 34.940 | Eocene, Priabonian | 5 | Chron C14 does not exist |
| C16n.1n | 35.343 | 35.526 | Eocene, Priabonian | 5 |
|
| C16n.2n | 35.685 | 36.341 | Eocene, Priabonian | 5 |
|
| C17n.1n | 36.618 | 37.473 | Eocene, Priabonian | 5 |
|
| C17n.2n | 37.604 | 37.848 | Eocene, Bartonian | 5 |
|
| C17n.3n | 37.920 | 38.113 | Eocene, Bartonian | 5 |
|
| C18n.1n | 38.426 | 39.552 | Eocene, Bartonian | 5 |
|
| C18n.2n | 39.631 | 40.130 | Eocene, Bartonian | 5 |
|
| C19n | 41.257 | 41.521 | Eocene, Lutetian | 5 |
|
| C20n | 42.536 | 43.789 | Eocene, Lutetian | 5 |
|
| C21n | 46.264 | 47.906 | Eocene, Lutetian | 5 | 46.8 Ma at upper Chron C21n (Subchron C21n.67) is an age control point of 5 |
| C22n | 49.037 | 49.714 | Eocene, Ypresian | 5 |
|
| C23n.1n | 50.778 | 50.946 | Eocene, Ypresian | 5 |
|
| C23n.2n | 51.047 | 51.743 | Eocene, Ypresian | 5 |
|
| C24n.1n | 52.364 | 52.663 | Eocene, Ypresian | 5 |
|
| C24n.2n | 52.757 | 52.801 | Eocene, Ypresian | 5 |
|
| C24n.3n | 52.903 | 53.347 | Eocene, Ypresian | 5 |
|
| C25n | 55.904 | 56.391 | Paleocene, Thanetian | 5 |
|
| C26n | 57.554 | 57.911 | Paleocene, Thanetian | 5 | Selandian stage is approximately equivalent to Chron C26r (6) |
| C27n | 60.920 | 61.276 | Paleocene, Danian | 5 |
|
| C28n | 62.499 | 63.634 | Paleocene, Danian | 5 |
|
| C29n | 63.976 | 64.745 | Paleocene, Danian | 5 | 65.0 Ma at Subchron C29r.7 (Maastrichtian/Paleocene boundary) is an age control of 5 |
| C30n | 65.578 | 67.610 | Maastrichtian | 5 |
|
| C31n | 67.735 | 68.737 | Maastrichtian | 5 |
|
| C32n.1n | 71.071 | 71.338 | Maastrichtian | 5 |
|
| C32n.2n | 71.587 | 73.004 | Campanian | 5 |
|
| C32r.1n | 73.291 | 73.374 | Campanian | 5 |
|
| C33n | 73.619 | 79.075 | Campanian | 5 |
|
| C34n | 83.000 |
|
Santonian to Aptian | 5 | 83.0 Ma at base of Chron C33r (base of Campanian) is an age control of 5 |
Notes: Ages of polarity chrons are from compilations published before 1995 but were retained to be consistent with the biostratigraphic age scales during Leg 207 (see "Biostratigraphy"). References: 1 = Shackleton et al. (1990), 2 = Hilgen (1991a), 3 = Hilgen (1991b), 4 = Shackleton et al. (1995), 5 = Cande and Kent (1995), 6 = Berggren et al. (1995b).