*The Pleistocene is divided into four ages, but only two are shown here. What is shown as Calabrian is actually three ages: Calabrian from 1.8 to
0.774 Ma, Chibanian from 0.774 to 0.129 Ma, and Late from 0.129 to 0.0117 Ma. The Holocene is divided into three ages: Greenlandian from 0.0117
to 0.0082 Ma, Northgrippian from 0.0082 to 0.0042 Ma, and Meghalayan from 0.0042 to present. The geologic community broadly recognizes the
Anthropocene as a proposed new time interval of Earth history, partly coincident with the Holocene. Currently, the Anthropocene has an informal
designation, with a proposed age span extending from the present to a beginning point between ca. 15,000 yr B.P. and as recent as 1960 CE.
The Cenozoic, Mesozoic, and Paleozoic are the Eras of the Phanerozoic Eon. Names of units and age boundaries usually follow the Gradstein et al.
(2012), Cohen et al. (2012), and Cohen et al. (2013, updated) compilations. Numerical age estimates and picks of boundaries usually follow the
Cohen et al. (2013, updated) compilation. The numbered epochs and ages of the Cambrian are provisional. A “~” before a numerical age estimate
typically indicates an associated error of ± 0.4 to more than 1.6 Ma.
REFERENCES CITED
Cohen, K.M., Finney, S., and Gibbard, P.L., 2012, International Chronostratigraphic Chart: International Commission on Stratigraphy, https://stratigra-
phy.org/ICSchart/ChronostratChart2012.pdf (accessed Sept. 2022).
Cohen, K.M., Finney, S.C., Gibbard, P.L., and Fan, J.-X., 2013 (updated), The ICS International Chronostratigraphic Chart: Episodes, v.36, p.199–204,
http://www.stratigraphy.org/ICSchart/ChronostratChart2021-10.pdf (accessed Sept. 2022).
Gradstein, F.M, Ogg, J.G., Schmitz, M.D., et al., 2012, The Geologic Time Scale 2012: Boston, USA, Elsevier,
https://doi.org/10.1016/B978-0-444-59425-9.00004-4.
©2022 The Geological Society of America | www.geosociety.org
Walker, J.D., and Geissman, J.W., compilers, 2022, Geologic Time Scale v. 6.0: Geological Society of America, https://doi.org/10.1130/2022.CTS006C.
(Walker—University of Kansas; Geissman—University of Texas–Dallas, University of New Mexico.)
70
80
90
100
110
120
130
140
150
160
170
180
190
210
200
220
230
240
250
HIST
ANOM.
CHRON.
C31
C32
C33
31
32
33
M0r
M1
M5
M10
M12
M14
M16
M18
M20
M22
M25
M29
M3
RAPID POLARITY CHANGES
30 C30
C34
34
TRIASSIC JURASSIC CRETACEOUS
AGE
(Ma) EPOCH AGE PICKS
(Ma)
MAGNETIC
POLARITY PERIOD
LATE
EARLY
LATE
EARLY
MIDDLE
LATE
EARLY
MIDDLE
MAASTRICHTIAN
CAMPANIAN
SANTONIAN
CONIACIAN
TURONIAN
CENOMANIAN
ALBIAN
APTIAN
BARREMIAN
HAUTERIVIAN
VALANGINIAN
BERRIASIAN
TITHONIAN
KIMMERIDGIAN
OXFORDIAN
CALLOVIAN
BATHONIAN
BAJOCIAN
AALENIAN
TOARCIAN
PLIENSBACHIAN
SINEMURIAN
HETTANGIAN
NORIAN
RHAETIAN
CARNIAN
LADINIAN
ANISIAN
OLENEKIAN
INDUAN
~237
66.0
72.1
83.6
86.3
89.8
93.9
100.5
~113
~125
~129.4
~132.6
~139.8
~145.0
152.1
157.3
166.1
163.5
168.3
170.3
174.1
199.3
190.8
201.3
~208.5
~242
~227
251.90
251.2
247.2
182.7
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
3250
3500
3750
4000
PROTEROZOICARCHEAN
AGE
(Ma) EON ERA
BDY.
AGES
(Ma)
1000
1200
1800
2050
2300
1400
1600
2500
2800
3200
3600
4000
541
635
720
PERIOD
EDIACARAN
CRYOGENIAN
TONIAN
STENIAN
ECTASIAN
CALYMMIAN
STATHERIAN
OROSIRIAN
RHYACIAN
SIDERIAN
NEOPRO-
TEROZOIC
MESOPRO-
TEROZOIC
PALEOPRO-
TEROZOIC
NEOARCHEAN
MESO-
ARCHEAN
PALEO-
ARCHEAN
EOARCHEAN
HADEAN
260
280
300
320
340
380
360
400
420
440
460
480
500
520
540
PERMIAN
DEVONIAN
ORDOVICIAN SILURIAN
MISSIS-
SIPPIAN
PENNSYL-
VANIAN
CAMBRIAN CARBONIFEROUS
AGE
(Ma) EPOCH AGE PICKS
(Ma)
PERIOD
GZHELIAN
KASIMOVIAN
MOSCOVIAN
BASHKIRIAN
SERPUKHOVIAN
VISEAN
TOURNAISIAN
FAMENNIAN
FRASNIAN
GIVETIAN
EIFELIAN
EMSIAN
PRAGIAN
LOCHKOVIAN
Lopin-
gian
MIDDLE
Guada-
lupian
Cisura-
lian
LLANDO-
VERY
EARLY
EARLY
FURON-
GIAN
MIAOLIN-
GIAN
Epoch 2
TERRE-
NEUVIAN
LATE
LUDLOW
LATE
MIDDLE
WENLOCK
CHANGHSINGIAN
WORDIAN
ROADIAN
WUCHIAPINGIAN
CAPITANIAN
KUNGURIAN
ASSELIAN
SAKMARIAN
ARTINSKIAN
PRIDOLI
LUDFORDIAN
GORSTIAN
HOMERIAN
RHUDDANIAN
TELYCHIAN
AERONIAN
SHEINWOODIAN
HIRNANTIAN
SANDBIAN
KATIAN
DARRIWILIAN
DAPINGIAN
AGE 10
JIANGSHANIAN
PAIBIAN
GUZHANGIAN
DRUMIAN
WULIUAN
AGE 4
AGE 3
AGE 2
FORTUNIAN
FLOIAN
TREMADOCIAN
EARLY
EARLY
MIDDLE
MIDDLE
LATE
LATE
251.90
259.51
254.14
264.28
266.9
273.01
283.5
290.1
293.52
303.7
307.0
298.9
323.2
330.9
346.7
358.9
372.2
382.7
387.7
393.3
407.6
410.8
419.2
423.0
425.6
433.4
430.5
438.5
440.8
427.4
443.8
445.2
453.0
458.4
470.0
467.3
477.7
485.4
~494
~497
~500.5
~504.5
489.5
~509
~514
~521
~529
541.0
315.2
5
10
15
20
25
30
35
40
45
50
55
60
65
1
2
2A
3
3A
4
4A
5
5B
5A
5C
6
6A
6B
7
8
9
10
11
12
13
15
16
17
18
19
20
21
22
23
24
25
28
29
26
27
7A
6C
5D
5E
30
MIOCENEOLIGOCENEEOCENEPALEOCENE
PLIOCENE PIACENZIAN
ZANCLEAN
MESSINIAN
TORTONIAN
SERRAVALLIAN
LANGHIAN
BURDIGALIAN
AQUITANIAN
CHATTIAN
RUPELIAN
PRIABONIAN
BARTONIAN
LUTETIAN
YPRESIAN
DANIAN
THANETIAN
SELANDIAN
PALEOGENE NEOGENE
TERTIARY
GEOLOGIC TIME SCALE v. 6.0
MESOZOIC
PRECAMBRIANPALEOZOICCENOZOIC
AGE
(Ma) EPOCH AGE PICKS
(Ma)
MAGNETIC
PERIOD
HIST.
ANOM.
CHRON.
POLARITY
QUATER-
NARY PLEISTOCENE*
HOLOCENE*CALABRIAN
GELASIAN
C1
C2
C2A
C3
C3A
C4
C4A
C5
C5A
C6
C6A
C6B
C6C
C7
C5B
C5C
C5D
C5E
C8
C9
C10
C7A
C11
C12
C13
C15
C16
C17
C18
C19
C20
C21
C22
C23
C24
C25
C26
C27
C28
C29
C30
0.012
1.8
3.600
5.333
7.246
11.63
13.82
15.97
20.44
23.03
27.82
33.9
37.71
41.2
47.8
56.0
59.2
61.6
66.0
2.58
