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Table T7. Geomagnetic polarity timescale used during Expedition 342.

Geological
age 		Base age
(Ma) 		  Polarity chron   Age (Ma) Duration (m.y.) Remarks
Top Base
Neogene              
Holocene 11.5 ka            
Pleistocene   C1 C1n (Brunhes) 0 0.781 0.781 Base of middle Pleistocene (Ionian) is base of Brunhes Chron.
late (Tarantian) 0.126   C1r.1r (Matuyama) 0.781 0.988 0.207  
middle (Ionian) 0.781   C1r.1n (Jaramillo) 0.988 1.072 0.084  
      C1r.2r 1.072 1.173 0.101  
      C1r.2n (Cobb Mountain) 1.173 1.185 0.012 Cobb Mountain cryptochron is within early part of Matuyama Chron (C1r).
      C1r.3r 1.185 1.778 0.593  
early (Calabrian) 1.806 C2 C2n (Olduvai) 1.778 1.945 0.167 Base of Calabrian is in lower part of Olduvai Chron.
      C2r.1r 1.945 2.128 0.183  
      C2r.1n (Reunion) 2.128 2.148 0.020  
      C2r.2r (Matuyama) 2.128 2.581 0.453 Base of Pleistocene is near base of Matuyama Chron.
(Gelasian) 2.588            
Pliocene   C2A C2An.1n (Gauss) 0.000 3.032 3.032 “Gauss normal chron” (C2An) contains two reversed intervals: Kaena (2An.1r)
and Mammoth (2An.2r).
      C2An.1r (Keana) 3.032 3.116 0.084  
      C2An.2n 3.116 3.207 0.091  
      C2An.2r (Mammoth) 3.207 3.330 0.123  
late (Piacenzian) 3.600   C2An.3n (Gauss) 3.330 3.596 0.266 Base of Piacenzian is base of Chron C2An.3n.
      C2Ar (Gilbert) 3.596 4.187 0.591 “Gilbert reversed chron” spans Chrons C2Ar through C3r.
    C3 C3n.1n (Cochiti) 4.187 4.300 0.113  
      C3n.1r 4.300 4.493 0.193  
      C3n.2n (Nunivak) 4.493 4.631 0.138  
      C3n.2r 4.631 4.799 0.168  
      C3n.3n (Sidufjall) 4.799 4.896 0.097  
      C3n.3r 4.896 4.997 0.101  
early (Zanclean) 5.332   C3n.4n (Thvera) 4.997 5.235 0.238 Base of Miocene is in uppermost Chron C3r.
Miocene     C3r (Gilbert) 5.235 6.033 0.798  
    C3A C3An.1n 6.033 6.252 0.219  
      C3An.1r 6.252 6.436 0.184  
      C3An.2n 6.436 6.733 0.297  
      C3Ar 6.733 7.140 0.407  
    C3B C3Bn 7.140 7.212 0.072  
late (Messinian) 7.246   C3Br.1r 7.212 7.251 0.039 Base of Messinian is in lowermost Chron C3Br.1r.
      C3Br.1n 7.251 7.285 0.034  
      C3Br.2r 7.285 7.454 0.169  
      C3Br.2n 7.454 7.489 0.035  
      C3Br.3r 7.489 7.528 0.039  
    C4 C4n.1n 7.528 7.642 0.114  
      C4n.1r 7.642 7.695 0.053  
      C4n.2n 7.695 8.108 0.413  
      C4r.1r 8.108 8.254 0.146  
      C4r.1n 8.254 8.300 0.046  
      C4r.2r 8.300 8.771 0.471 Cryptochron C4r.2r-1 is within C4r.2r (~8.661−8.699 Ma).
    C4A C4An 8.771 9.105 0.334  
      C4Ar.1r 9.105 9.311 0.206  
      C4Ar.1n 9.311 9.426 0.115  
      C4Ar.2r 9.426 9.647 0.221  
      C4Ar.2n 9.647 9.721 0.074  
      C4Ar.3r 9.721 9.786 0.065  
    C5 C5n.1n 9.786 9.937 0.151  
      C5n.1r 9.937 9.984 0.047  
      C5n.2n 9.984 11.056 1.072 Cryptochrons C5n.2n-1, C5n.2n-2, and C5n.2n-3.
      C5r.1r 11.056 11.146 0.090  
      C5r.1n 11.146 11.188 0.042  
      C5r.2r 11.188 11.592 0.404 Subchron C5r.2r-1 is within C5r.2r (~11.263−11.308 Ma).
(Tortonian) 11.63   C5r.2n 11.592 11.657 0.065 Base of Tortonian is near base of Chron C5r.2n.
      C5r.3r 11.657 12.049 0.392  
    C5A C5An.1n 12.049 12.174 0.125  
      C5An.1r 12.174 12.272 0.098  
      C5An.2n 12.272 12.474 0.202  
      C5Ar.1r 12.474 12.735 0.261  
      C5Ar.1n 12.735 12.770 0.035  
      C5Ar.2r 12.770 12.829 0.059  
      C5Ar.2n 12.829 12.887 0.058  
      C5Ar.3r 12.887 13.032 0.145  
    C5AA C5AAn 13.032 13.183 0.151  
      C5AAr 13.183 13.363 0.180  
    C5AB C5ABn 13.363 13.608 0.245  
      C5ABr 13.608 13.739 0.131  
middle (Serravallian) 13.82 C5AC C5ACn 13.739 14.070 0.331 Base of Serravalian is upper Chron C5ACn.
      C5ACr 14.070 14.163 0.093  
    C5AD C5ADn 14.163 14.609 0.446  
      C5ADr 14.609 14.775 0.166  
    C5B C5Bn.1n 14.775 14.870 0.095  
      C5Bn.1r 14.870 15.032 0.162  
      C5Bn.2n 15.032 15.160 0.128  
(Langhian) 15.97   C5Br 15.160 15.974 0.814 Base of Langhian is base of Chron C5Br.
    C5C C5Cn.1n 15.974 16.268 0.294  
      C5Cn.1r 16.268 16.303 0.035  
      C5Cn.2n 16.303 16.472 0.169  
      C5Cn.2r 16.472 16.543 0.071  
      C5Cn.3n 16.543 16.721 0.178  
      C5Cr 16.721 17.235 0.514  
    C5D C5Dn 17.235 17.533 0.298  
      C5Dr.1r 17.533 17.717 0.184  
      C5Dr.1n 17.717 17.740 0.023 Cryptochron is in Chron C5Dr.
      C5Dr.2r 17.740 18.056 0.316  
    C5E C5En 18.056 18.524 0.468  
      C5Er 18.524 18.748 0.224  
    C6 C6n 18.748 19.722 0.974  
      C6r 19.722 20.040 0.318 Cryptochron C6r-1.
    C6A C6An.1n 20.040 20.213 0.173  
early (Burdigalian) 20.44   C6An.1r 20.213 20.439 0.226 Base of Burdigalian (working version) is approximately base of Chron C6An.1r
(used here) or of Chron C6An.1n.
      C6An.2n 20.439 20.709 0.270  
      C6Ar 20.709 21.083 0.374  
    C6AA C6AAn 21.083 21.159 0.076  
      C6AAr.1r 21.159 21.403 0.244  
      C6AAr.1n 21.403 21.483 0.080  
      C6AAr.2r 21.483 21.659 0.176  
      C6AAr.2n 21.659 21.688 0.029  
      C6AAr.3r 21.688 21.767 0.079  
    C6B C6Bn.1n 21.767 21.936 0.169  
      C6Bn.1r 21.936 21.992 0.056  
      C6Bn.2n 21.992 22.268 0.276  
      C6Br 22.268 22.564 0.296  
    C6C C6Cn.1n 22.564 22.754 0.190  
      C6Cn.1r 22.754 22.902 0.148  
(Aquitanian) 23.03   C6Cn.2n 22.902 23.030 0.128 Base of Miocene is base of Chron C6Cn.2n.
Paleogene     C6Cn.2r 23.030 23.233 0.203  
Oligocene     C6Cn.3n 23.233 23.295 0.062  
      C6Cr 23.295 23.962 0.667  
    C7 C7n.1n 23.962 24.000 0.038  
      C7n.1r 24.000 24.109 0.109  
      C7n.2n 24.109 24.474 0.365  
      C7r 24.474 24.761 0.287 Cryptochron C7r-1.
    C7A C7An 24.761 24.984 0.223  
      C7Ar 24.984 25.099 0.115  
    C8 C8n.1n 25.099 25.264 0.165  
      C8n.1r 25.264 25.304 0.040  
      C8n.2n 25.304 25.987 0.683 Cryptochron C8n.2n-1.
      C8r 25.987 26.420 0.433  
    C9 C9n 26.420 27.439 1.019 Cryptochrons C9n-1and C9n-2.
      C9r 27.439 27.859 0.420 Cryptochron C9r-1.
late (Chattian) 28.09 C10 C10n.1n 27.859 28.087 0.228 Base of Chattian (working version) is base of Chron C10n.1n. Base is
potentially at ~70% up in “undifferentiated Chron C10n” in candidate
GSSP in Italy (Coccioni et al., 2008), which would project as equivalent to
Chron C10n.1n.4.
      C10n.1r 28.087 28.141 0.054  
      C10n.2n 28.141 28.278 0.137  
      C10r 28.278 29.183 0.905 Cryptochrons C10r-1 and C10r-2.
    C11 C11n.1n 29.183 29.477 0.294  
      C11n.1r 29.477 29.527 0.050  
      C11n.2n 29.527 29.970 0.443  
      C11r 29.970 30.591 0.621 Cryptochron C11r-1.
    C12 C12n 30.591 31.034 0.443  
      C12r 31.034 33.157 2.123 Cryptochrons C12r-1 through C12r-8.
    C13 C13n 33.157 33.705 0.548 Cryptochron C13n-1.
early (Rupelian) 33.89   C13r 33.705 34.999 1.294 Base of Rupelian is at Chron C13r.86.
Cryptochrons C13r-1 through C13r-4
Eocene   C15 C15n 34.999 35.294 0.295 “C14” does not exist.
      C15r 35.294 35.706 0.411  
    C16 C16n.1n 35.706 35.892 0.186  
      C16n.1r 35.892 36.051 0.159  
      C16n.2n 36.051 36.700 0.649  
      C16r 36.700 36.969 0.269  
late (Priabonian) 37.75 C17 C17n.1n 36.969 37.753 0.784 Base of Priabonian (working version) assigned as base of Chron C17n.1n.
      C17n.1r 37.753 37.872 0.119  
      C17n.2n 37.872 38.093 0.221  
      C17n.2r 38.093 38.159 0.065  
      C17n.3n 38.159 38.333 0.174  
      C17r 38.333 38.615 0.283  
    C18 C18n.1n 38.615 39.627 1.012 Cryptochron C18n.1n-1.
      C18n.1r 39.627 39.698 0.070  
      C18n.2n 39.698 40.145 0.447  
middle (Bartonian) 41.15   C18r 40.145 41.154 1.010 Base of Bartonian (working version) assigned as base of Chron C18r.
    C19 C19n 41.154 41.390 0.235  
      C19r 41.390 42.301 0.912  
    C20 C20n 42.301 43.432 1.130  
      C20r 43.432 45.724 2.292  
    C21 C21n 45.724 47.349 1.625  
(Lutetian) 47.84   C21r 47.349 48.566 1.217 Base of Lutetian is Chron C21r.6.
    C22 C22n 48.566 49.344 0.778  
      C22r 49.344 50.628 1.283  
    C23 C23n.1n 50.628 50.835 0.207  
      C23n.1r 50.835 50.961 0.126  
      C23n.2n 50.961 51.833 0.872  
      C23r 51.833 52.620 0.787  
    C24 C24n.1n 52.620 53.074 0.454  
      C24n.1r 53.074 53.199 0.125  
      C24n.2n 53.199 53.274 0.075  
      C24n.2r 53.274 53.416 0.142  
      C24n.3n 53.416 53.983 0.567  
early (Ypresian) 55.96   C24r 53.983 57.101 3.118 Base of Eocene is 1.14 m.y. after beginning of Chron C24r, or Chron C24r.37.
Cryptochrons C24r-1 through C24r-11.
Paleocene   C25 C25n 57.101 57.656 0.555  
      C25r 57.656 58.959 1.303 Cryptochrons C25r-1 through C25r-5.
late (Thanetian) 59.24 C26 C26n 58.959 59.237 0.278 Base of Thanetian is base of Chron C26n.
middle (Selandian) 61.61   C26r 59.237 62.221 2.984 Base of Selandian is an isotope shift at 30. Precession cycles (0.61 m.y. if 20.5
k.y. cycles) above base of Chron C26r at GSSP. Cryptochrons C26r-1
through C26r-7.
    C27 C27n 62.221 62.517 0.296  
      C27r 62.517 63.494 0.977  
    C28 C28n 63.494 64.667 1.173  
      C28r 64.667 64.958 0.291 Cryptochron C28r-1
    C29 C29n 64.958 65.688 0.730  
early (Danian) 66.04   C29r 65.688 66.398 0.710 Mesozoic/Cenozoic boundary event is Chron C29r.5 in total Chron C29r span
of 710 k.y. according to cycles (Husson et al., 2011; Thibault et al.,
submitted).
Cretaceous   C30 C30n 66.398 68.196 1.798 Pre-Chron 29r C-sequence ages based entirely on cycle stratigraphy because
of lack of adequate radiometric age constraints. Duration of Chron C30n is
1.798 m.y. (Husson et al., 2011; Thibault et al., submitted).
      C30r 68.196 68.369 0.173 Duration of Chron C30r is 173 m.y. (Husson et al., 2011; Thibault et al.,
2012).
    C31 C31n 68.369 69.269 0.900 Duration of Chron C31n is 0.9 m.y. (Husson et al., 2011).
      C31r 69.269 71.449 2.180 Duration of Chron C31r is 2.18 m.y. (Husson et al., 2011).
Base of Chron C31r is within the lower Baculites grandis ammonite zone
constrained by Ar/Ar ages of 70.65 ± 0.65 Ma (2σ) within that zone.
    C32 C32n.1n 71.449 71.689 0.240 Duration of Chron C32n.1n is 0.24 m.y. (Husson et al, 2011).
      C32n.1r 71.689 71.939 0.250 Duration of Chron C32n.1r assigned as 0.25 m.y. (same as GTS2004 spline
fit).
Maastrichtian 72.05   C32n.2n 71.939 73.649 1.710 Base of Maastrichtian is approximately at Chron C32n.2n.9, or at 72.05 Ma
from spline fit to ammonite zones. Duration of Chron C32n.1n is 1.71 m.y.
(Husson et al., 2011).
      C32r.1r 73.649 73.949 0.300 Duration of Chron C32r.1r is 0.3 m.y. (Husson et al., 2011).
      C32r.1n 73.949 74.049 0.100 Duration of Chron C32r.1n is 0.1 m.y. (Husson et al., 2011).
      C32r.2r 74.049 74.309 0.260 Duration of Chron C32n.2r assigned as 0.26 m.y. (same as GTS2004 spline
fit).
    C33 C33n 74.309 79.900 5.591 Base of Chron C33n constrained by Ar/Ar dates to be slightly younger than
80.08 Ma ± 0.61 m.y.; following Hicks (1995), it is extrapolated as 0.2 m.y.
younger (79.9 m.y.).
Campanian 83.64   C33r 79.900 83.640 3.740 Base of Chron C33r assigned as base of Campanian as in North American
ammonite zonation, with age from spline fit of the bracketing bentonites.
Santonian   C34 C34n 83.64     Chron C33r may include upper part of the English Chalk usage of Santonian.

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