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