Starting from version 2012 = the version distributed August 2012 at 34th IGC Brisbane, this change log lists: Changes ICS chart v.2013/01 Changes ICS chart v.2013/Episodes Changes ICS chart v.2014/02 Changes ICS chart v.2014/10 Changes ICS chart v.2015/01 Changes ICS chart v.2016/04 = the version distributed at 35th IGC Cape Town in August 2016 Changes ICS chart v.2016/10 Changes ICS chart v.2016/12 Changes ICS chart v.2017/02 Changes ICS chart v.2018/07 Changes ICS chart v.2018/08 Changes ICS chart v.2019/05 Changes ICS chart v.2020/01 = the version intended for distribution at the time of 36th IGC Delhi in 2020 (congress COVID-cancelled) Changes ICS chart v.2020/03 Changes ICS chart v.2021/05 Changes ICS chart v.2021/07 Changes ICS chart v.2021/10 Changes ICS chart v.2022/02 Changes ICS chart v.2022/10 Changes ICS chart v.2023/04 Changes ICS chart v.2023/06 Changes ICS chart v.2023/09 = the version distributed at 37th IGC Busan in August 2024 Changes ICS chart v.2024/12 = actual version GSSPs added: 2024/12 - Cretaceous: Valanginian Stage: GSSP added as it was ratified by IUGS (18-12-2024) 2023/06 - Miocene: Langhian Stage: GSSP added as it was ratified by IUGS (31-05-2023) 2023/04 - Cretaceous: Barremian Stage: GSSP added as it was ratified by IUGS (26-03-2023) 2022/10 - Cretaceous: Campanian Stage: GSSP added as it was ratified by IUGS (5-10-2022) 2022/02 - Permian: Artinskian Stage: GSSP added as it was ratified by IUGS (03-02-2022) 2021/05 - Cretaceous: Coniacian Stage: GSSP added as it was ratified by IUGS (02-05-2021) - Jurassic: Kimmeridgian Stage: GSSP added as it was ratified by IUGS (07-03-2021) 2020/03 - Paleogene: Priabonian Stage: GSSP added as it was ratified by IUGS (17-02-2020) 2020/01 - Cretaceous: Hauterivian Stage: GSSP added as it was ratified by IUGS (15-12-2019) - Quaternary: Chibanian Stage: GSSP added as it was ratified by IUGS (15-01-2020) 2018/07 - Permian: Sakmarian Stage: GSSP added as it was ratified by IUGS (21-7-2018) 2018/07 - Cambrian: Miaolingian Series (was Series 3) / Wuliuan Stage (was Stage 5): GSSP added as it was ratified by IUGS (26-06-2018) 2018/07 - Quaternary: Holocene Series / divided in tree stages: Greenlandian, Northgrippian, Meghalayan; GSSPs ratified by IUGS (26-06-2018) - in top of the first column, the graphic thickness of the Holocene was modestly increased and that of the Late and Middle Pleistocene decreased. Two lines were added to partition the Holocene Series in three. 2016/10 - Paleogene: Chattian Stage: GSSP added as it was ratified by IUGS (1-10-2016) 2016/04 - Cretaceous: Albian Stage: GSSP added as it was ratified by IUGS (8-4-2016) 2015/01 - Jurassic: Toarcian Stage: GSSP added as it was ratified. 2013 - Cretaceous: Santonian Stage: GSSP added as it was ratified. GSSAs changed/dropped/introduced: 2023/09 - Archean: base Eoarchean Erathem GSSA defined at 4,031 ± 3 Ma. This replaces the informal GSSA of ~4,000. 2022/10 - Hadean: GSSA instated as ratified by IUGS (5-10-2022). The GSSA is 4,567.30 ± 0.16 Ma. The chart displays it in rounded form: 4,567 Ma. This replaces non-GSSA provisional age of ~ 4,600 Ma. 2015/01 - base Cryogenian: changed to ~720 Ma (was 850 Ma, an Episodes paper by the subcommission in preparation). - In the outer right column, the graphic thickness of Cryogenian was reduced and that of the Tonian increased. 2016/04 - With the tuned age of the base Cryogenian being established, it is no-longer a ratified GSSA and the icon is dropped. Numeric Ages altered: 2024/12 - Large update to many (44) numerical ages, to resync with GTS2020 (Gradstein et al., 2020; was GTS2012, Gradstein et al., 2012), unless prevailed over by ICS commission descions. Lines beginning with dots (.) indicate stages with no updates. A remark indicates why. Number of dots is number of no-numeric-age change stages. TOP-OF-CHART .......... Quaternary and Neogene stages above Langhian: GTS2020 matches ICS2023/09 ages. . Miocene: Langhian Stage: see 2023/06, stays 15.98 Ma Miocene: Burdigalian Stage: 20.45 Ma (was: 20.44 Ma) - following GTS2020 (Ch 29; Raffi et al. 2020) - minor update Miocene: Aquitanian Stage: 23.04 Ma (was: 23.03 Ma) - following GTS2020 (Ch 29; Raffi et al. 2020) - minor update Oligocene: Chattian Stage: 27.30 Ma (was: 27.82 Ma), two decimal rounded calibrated age for C9n.139 (27.2963 Ma; Paleogene Subcommission), close to GTS2020 (ch28; section 28.3.3: Speijer et al. 2020: 27.29 Ma) .. Oligocene: Rupelian Stage and Eocene: Priabonian stage: prior featured ages and GTS2020 ages are the same Eocene: Bartonian Stage: 41.03 Ma (was: 41.2 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update Eocene: Lutetian Stage: 48.07 Ma (was: 47.8 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update Eocene: Ypresian Stage: 56.00 Ma (was: 56.0 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update (accuracy only) Paleocene: Thanetian Stage: 59.24 Ma (was: 59.2 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update Paleocene: Selandian Stage: 61.66 Ma (was: 61.6 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update Paleocene: Danian Stage: 66.00 Ma (was: 66.0 Ma) - following GTS2020 (ch28, Speijer et al. 2020) - minor update (accuracy only) CENOZOIC/MESOZOIC BOUNDARY Upper Cretaceous: Maastrichtian Stage: 72.2 +/- 0.2 Ma (was: 72.1 +/- 0.2 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update . Campanian Stage: not updated: see 2022/10, GSSP age there prevails GTS2020 Upper Cretaceous: Santonian Stage: 85.7 +/- 0.2 Ma (was: 86.3 +/- 0.5 Ma) - following GTS2020 (ch27, Gale et al. 2020) - 0.6 Ma younger . Coniacian Stage: not updated: see 2021/05, GSSP age there prevails GTS2020 Upper Cretaceous: Turonian Stage: 93.9 +/- 0.2 Ma (was: 93.9 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update (accuracy only) Upper Cretaceous: Cenomanian Stage: 100.5 +/- 0.1 Ma (was: 100.5 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update (accuracy only) Lower Cretaceous: Albian Stage: 113.2 +/- 0.3 Ma (was: 113.0 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update (age and accuracy) Lower Cretaceous: Aptian Stage: 121.4 +/- 0.6 Ma (was: 121.4 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update (accuracy only) . Barremian Stage: not updated: see 2023/04, GSSP age there prevails GTS2020 Lower Cretaceous: Hauterivian Stage: 132.6 +/- 0.6 Ma (was: 132.6 Ma) - following GTS2020 (ch27, Gale et al. 2020) - minor update (accuracy only) Lower Cretaceous: Valanginian Stage: 137.05 +/- 0.20 Ma (was: 139.8 Ma): Age with GSSP ratified 18-12-2024; GSSP age there prevails GTS2020. Lower Cretaceous: Berriasian Stage: 143.1 Ma (was: 145.0 Ma) - following GTS2020 (ch27, Gale et al. 2020) - 1.9 Ma younger ........... Jurassic stage ages: see 2022/10: GTS2020 syncing based on (ch26, Hesselbo et al. 2020) had already taken place Upper Triassic: Rhaetian Stage: 205.7 Ma (was: 208.5 Ma) - following GTS2020 (ch25, Ogg et al. 2020) and Maron et al. (2015) and Rigo et al. (2016) cited therein - 2.8 Ma younger Upper Triassic: Norian Stage: 227.3 Ma (was: 227 Ma) - following GTS2020 (ch25, Ogg et al. 2020) and Maron et al. (2015) and Rigo et al. (2016) cited therein - minor update (age and accuracy) . Carnian Stage: GTS2020 age unchanged to GTS2012, stays 237 Ma Middle Triassic: Ladinian Stage: 241.464 +/- 0.28 Ma (was: 242 Ma) - following GTS2020 (ch25, Ogg et al. 2020) and Wotzlaw et al. (2018) and Maron et al. (2019) cited therein - minor update (age and accuracy) Middle Triassic: Anisian Stage: 246.7 Ma (was: 247.2 Ma) - following GTS2020 (ch25, Ogg et al. 2020) and Chen et al. (2020) cited therein - 0.5 Ma younger Lower Triassic: Olenekian Stage: 249.9 Ma (was: 251.2 Ma) - following GTS2020 (ch25, Ogg et al. 2020) and Li et al. (2016) cited therein - 1.3 Ma younger . Induan Stage: 2016/12 numeric age (from Burgess et al. 2014) is GTS2020 age, stays 251.902 +/- 0.024 Ma MESOZOIC/PALEOZOIC BOUNDARY . Permian: Lopingian: Changhsingian Stage: not updated: see 2013, age-precision prevails (GTS2020 difference <0.1 Ma), stays 254.14 +/- 0.07 Ma . Permian: Lopingian: Wuchiapingian Stage: not updated: see 2021/07, numeric age and precision prevail (GTS2020 difference <0.1 Ma), stays 259.51 +/- 0.21 Ma . Permian: Guadalupian: Capitanian Stage: not updated: see 2021/07, numeric age and precision prevail (GTS2020 difference <0.1 Ma), stays 264.28 +/- 0.16 Ma . Permian: Guadalupian: Wordian Stage: not updated: 2021/07 numeric age and precision prevail, stays 266.9 +/- 0.4 Ma Permian: Guadalupian: Roadian Stage: 274.4 +/- 0.4 Ma (was: 273.01 +/- 0.14 Ma) - following GTS2020 (ch24, Henderson et al., 2020) - 1.39 Ma older Permian: Cisuralian: Kungurian Stage: 283.3 +/- 0.4 Ma (was: 283.5 +/- 0.6 Ma) - following GTS2020 (ch24, Henderson et al., 2020) - 0.2 Ma younger . Permian: Cisuralian: Artinskian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 290.1 +/- 0.26 Ma . Permian: Cisuralian: Sakmarian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 293.52 +/- 0.17 Ma . Permian: Cisuralian: Asselian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 298.9 +/- 0.2 Ma . Carboniferous: Upper Pennsylvanian: Gzhelian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 303.7 +/- 0.1 Ma . Carboniferous: Upper Pennsylvanian: Kasimovian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 307.0 +/- 0.1 Ma . Carboniferous: Middle Pennsylvanian: Moscovian Stage: not updated, GTS2012 (Schmitz & Davydov, 2012 GSA Bulletin) ages maintained, stays 315.2 +/- 0.2 Ma Carboniferous: Lower Pennsylvanian: Bashkirian Stage: 323.4 +/- 0.4 Ma (was: 323.2 +/- 0.4 Ma) - following GTS2020 (ch23, Aretz et al. 2020) - minor update Carboniferous: Upper Mississippian: Serpukhovian Stage: 330.3 +/- 0.4 Ma (was: 330.9 +/- 0.3 Ma) - following GTS2020 (ch23, Aretz et al. 2020) - 0.6 Ma younger . Carboniferous: Middle Mississippian: Visean Stage: GTS2020 age unchanged to GTS2012, stays 346.7 +/- 0.4 Ma Carboniferous: Lower Mississippian: Tournaisian Stage: 358.86 +/- 0.19 Ma (was: 358.9 +/- 0.4 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Upper Devonian: Famennian Stage: 372.15 +/- 0.46 Ma (was: 372.2 +/- 1.6 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Upper Devonian: Frasnian Stage: 382.31 +/- 1.36 Ma (was: 382.7 +/- 1.6 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Middle Devonian: Givetian Stage: 387.95 +/- 1.04 Ma (was: 387.7 +/- 0.8 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Middle Devonian: Eifelian Stage: 393.47 +/- 0.99 Ma (was: 393.3 +/- 1.2 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Lower Devonian: Emsian Stage: 410.62 +/- 1.95 Ma (was: 407.6 +/- 2.6 Ma anticipating newEmsian) - following Harrigan et al. (2022; not GTS2020) - A redefinition of the GSSP (newEmsian) is considered with an age of ~407.6 Ma. Lower Devonian: Pragian Stage: 413.02 +/- 1.91 Ma (was: 410.8 +/- 2.8 Ma) - following Harrigan et al. (2022; not GTS2020) - 2.2 Ma older Lower Devonian: Lochkovian Stage: 419.62 +/- 1.36 Ma (was: 419.2 +/- 3.2 Ma) - following Harrigan et al. (2022; not GTS2020) - minor update Silurian: Pridoli: Pridoli Stage: 422.7 +/- 1.6 Ma (was: 423.0 +/- 2.3 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Ludlow: Ludfordian Stage: 425.0 +/- 1.5 Ma (was: 425.6 +/- 0.9 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Ludlow: Gorstian Stage: 426.7 +/- 1.5 Ma (was: 427.4 +/- 0.5 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Wenlock: Homerian Stage: 430.6 +/- 1.3 Ma (was: 430.5 +/- 0.7 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Wenlock: Sheinwoodian Stage: 432.9 +/- 1.2 Ma (was: 433.8 +/- 0.8 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) Silurian: Llandovery: Telychian Stage: 438.6 +/- 1.0 Ma (was: 438.5 +/- 1.1 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Llandovery: Aeronian Stage: 440.5 +/- 1.0 Ma (was: 440.8 +/- 1.2 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Silurian: Llandovery: Rhuddanian Stage: 443.1 +/- 0.9 Ma (was: 443.8 +/- 1.5 Ma) - following GTS2020 (ch21 Melchin et al. 2020; age-modelled for Ordovician+Silurian, ch20 Goldman et al. 2020) - minor update Upper Ordovician: Hirnantian Stage: 445.2 +/- 0.9 Ma (was: 445.2 +/- 1.4 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - minor update, accuracy only Upper Ordovician: Katian Stage: 452.8 +/- 0.7 Ma (was: 453.0 +/- 0.7 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - minor update Upper Ordovician: Sandbian Stage: 458.2 +/- 0.7 Ma (was: 458.4 +/- 0.9 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - minor update Middle Ordovician: Darriwilian Stage: 469.4 +/- 0.9 Ma (was: 467.3 +/- 1.1 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - 2.1 Ma older Middle Ordovician: Dapingian Stage: 471.3 +/- 1.0 Ma (was: 470.0 +/- 1.4 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - 1.3 Ma older Lower Ordovician: Floian Stage: 477.1 +/- 1.2 Ma (was: 477.7 +/- 1.4 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - 0.6 Ma younger Lower Ordovician: Tremadocian Stage: 486.85 +/- 1.50 Ma (was: 485.4 +/- 1.9 Ma) - following GTS2020 (ch20 Goldman et al. 2020) - 1.45 Ma older Furongian: Stage 10 Stage: 491.0 Ma (was: 489.5 Ma) - following GTS2020 (ch19 Peng et al. 2020), related to lowered age of base Ordovician in ch20 Goldman et al. 2020) - 1.5 Ma older Furongian: Jiangshanian Stage: 494.2 Ma (was: 494 Ma) - following GTS2020 (ch19 Peng et al. 2020) - minor update ... Paibian, Guzhangian and Drumian stages: ages unchanged between GTS2012, GTS2020 and ICS2012-2023/09, no change. Miaolingian: Wuliuan Stage: ~506.5 Ma (was: ~509 Ma) - based on Karlstrom et al. (2020, Geology, 48: 425–430), Sundberg et al. 2020 (Geology, 48: 441–446), and Landing et al. (2023, Geological Magazine, 160: 1790–1816). Series 2: Stage 4 Stage: 514.5 Ma (was: 514 Ma) - following GTS2020 (ch19 Peng et al. 2020) - 0.5 Ma older .. Stage 3 and Stage 2: ages unchanged between GTS2012, GTS2020 and ICS2012-2023/09, no change. Terreneuvian: Fortunian Stage: numeric age is that of the 2022/02, but uncertaity increased: 538.8 +/- 0.6 Ma (was +/- 0.2 Ma)- minor update PHANEROZOIC/PRECAMBRIAN boundary ............. No changes to Precambrian system ages . Base Archean age (see 2023/09) at 4,031 Ma (4.031 Ga) prevails over GTS2020 age . Base Hadean age (see 2022/10) at 4,567 Ma (4.567 Ga) prevails over GTS2020 age. 2023/09 - Archean: base Eoarchean Erathem age set to 4031 ± 3 Ma in agreement with GSSA proposal (was ~4000 Ma). 2023/06 - Miocene: Langhian Stage: 15.98 (was: 15.97 Ma) in agreement with ratified Langhian GSSP proposal. 2023/04 - Cretaceous: Barremian Stage: 125.77 (was: ~129.4) in agreement with ratified Barremian GSSP proposal 2022/10 - Jurassic: numeric ages of all stages updated to comply to GTS2020 - by request of SCJS (Angela Coe) Tithonian 149.2 +/- 0.7 Ma (was: 152.1 +/- 0.9 Ma ) Kimmeridgian 154.8 +/- 0.8 Ma (was: 157.3 +/- 1.0 Ma ) Oxfordian 161.5 +/- 1.0 Ma (was: 163.5 +/- 1.0 Ma ) Callovian 165.3 +/-1.1 Ma (was: 166.1 +/- 1.2 Ma ) Bathonian 168.2 +/- 1.2 Ma (was: 168.3 +/- 1.3 Ma ) Bajocian 170.9 +/- 0.8 Ma (was: 170.3 +/- 1.4 Ma ) Aalenian 174.7 +/- 0.8 Ma (was: 174.1 +/- 1.0 Ma ) Toarcian 184.2 +/- 0.3 Ma (was: 182.7 +/- 0.7 Ma ) Pliensbachian 192.9 +/-0.3 Ma (was: 190.8 +/- 1.0 Ma ) Sinemurian 199.5 +/-0.3 Ma (was: 199.3 +/- 0.3 Ma ) Hettangian 201.4 +/- 0.2 Ma (was: 201.3 +/- 0.2 Ma ) 2022/10 - Hadean age set to 4567 in agreement with GSSA proposal (was ~4600 Ma). 2022/02 - Cambrian: numeric age base Fortunian is 538.8 +/- 0.2 Ma (Linnemann et al. 2019) - by request of SCaS (Per Alberg, Maoyan Zhu) 2022/02 - Cretaceous: numeric age base Aptian is 121.4 (GTS2020; Gradstein et al. 2020) - by request of CSC (Maria Rose Petrizio), in consultation with Aptian GSSP working group. 2021/07 - Permian: numeric age base Guadalupian (Roadian) is 273.01+/-0.14 Ma (Shen et al. 2020, ESR) - by request of SPS (Lucia Angiolini & Shen Shuzhong) - Permian: numeric age base Wordian is 266.9+/-0.4 Ma (Wu et al. 2020, Paleo-3) - by request of SPS (Lucia Angiolini & Shen Shuzhong) - Permian: numeric age base Capitanian is 264.28+/-0.16 Ma (Wu et al. 2020, Paleo-3) - by request of SPS (Lucia Angiolini & Shen Shuzhong) - Permian: numeric age base Lopingian is 259.51+/-0.21 Ma (Yang et al. 2018, EPSL) - by request of SPS (Lucia Angiolini & Shen Shuzhong) 2020/03 - Paleogene: numeric age Base Priabonian Stage changed to 37.71 Ma (was 37.8 Ma) - by request of SPgS (Simonetta Monechi), updated to that at the ratified GSSP. 2020/01 - Cretaceous: numeric age Base Hauterivian Stage changed to 132.6 Ma (was 132.9) - by request of CSC (Maria Rose Petrizio), in consultation with Hauterivian GSSP working group, awaiting GTS-2020 book publication, and based on data by Aguirre et al (2015) and Martinez et al. (2015) 132 Ma +/-1 Ma. - Quaternary: numeric age base Late Pleistocene (Subseries / unnamed Stage) changed to 129 ka (was 126 ka) - by request of SQS (Martin Head), anticipating renewed GSSP-candidate locality search. The age sought is near the mid-point of Termination II in the marine isotope stratigraphy. References: Drysdale et al. 2005; Tzedakis et al. 2018, 2019. - Quaternary: numeric age base Chibanian Stage changed to 774 ka (in accordance with GSSP documentation; GSSP is 1 m below base Brunhes Chron in the Chibanian type section; base Brunhes Chron at 773 ka provided the numeric age in prior chart versions) 2019/05 - Quaternary: numeric age Base Middle Pleistocene to 773 ka (was 781 ka) - by request of SQS (Martin Head). 2018/08 - Permian: numeric ages of the base Sakmarian changed to 293.52 +/-0.17 in accordance with GSSP - by request of SPS (Shen Shuzhong) 2018/07 - Holocene: numeric ages of the subseries added: base Meghalayan 0.0042, base Northgrippian 0.0082 2017/02 - Paleogene: Base of Chattian: The numeric age is updated to that at the ratified GSSP (27.82 Ma; Nanno et al. exp. 2017; by request of Simonetti Monechi) 2016/12 - Permian-Triassic boundary: 251.902 +/- 0.024 Ma (Burgess et al., 2014, PNAS) - by request of SPS (Shen Shuzhong) and STS (Mark Hounslow) 2016/12 - Permian: Base of Lopingian (Wuchiapingian): 259.1 +/- 0.5 Ma (Zhong et al., 2014, Lithos) - by request SPS (Shen Shuzhong) 2016/12 - Permian: Base of Guadalupian (Roadian): 272.95 +/- 0.11 Ma (Wu et al.,2016, Palaeo-3) - by request of SPS (Shen Shuzhong) 2015/01 - Proterozoic: base Cryogenian: ~720 (was 850; GSSA dropped, future GSSP anticipated) 2014/10 - Neogene: base Tortonian: 11.63 (cf. GTS2012; incorrectly was 11.62 in previous ICS charts) 2014/10 - Paleogene: base Priabonian: 37.8 (cf. GTS2012; incorrectly was 38.0 in previous ICS charts) 2014/10 - Paleogene: base Bartonian: 41.2 (cf. GTS2012; incorrectly was 41.3 in previous ICS charts) 2014/10 - Silurian: base Rhuddanian: 443.8 (cf. GTS2012; incorrectly was 443.4 in previous ICS charts) 2014/02 - Pleistocene: base Calabrian: 1.80 (removed 3rd decimal) - Argumentation to deviate from GTS2012: Gibbard & Head, 2009 2014/02 - Pleistocene: base Gelasian: 2.58 (removed 3rd decimal) - Argumentation to deviate from GTS2012: Gibbard & Head, 2009 2013 - Triassic: base Norian: ~227 2013 - Triassic: base Carnian: ~237 2013 - Base Triassic: base: 252.17 +/- 0.06 2013 - Permian: base Changhsingian: 254.14 +/- 0.07 2013 - Permian: base Wuchiapingian: 259.8 +/- 0.4 2013 - Permian: base Capitanian: 265.1 +/- 0.4 2013 - Permian: base Wordian: 268.8 +/- 0.5 2013 - Permian: base Roadian: 272.3 +/- 0.5 2013 - Permian: base Kungurian: 283.5 +/- 0.6 2013 - Permian: base Artinskian: 290.1 +/- 0.26 2013 - Permian: base Sakmarian: 295.0 +/- 0.18 2013 - Permian: base Asselian: 298.9 +/- 0.15 --------- Based on SPS Permian chart and communication with Triassic subcommission (S. Finney) 2013 - BASE OF CRETACEOUS, BASE OF CARBONIFERUOUS, BASE OF CAMBRIAN, the ages for these three also appear as top of Jurassic, Devonian, Ediacaran in the chart layout. the ages reported for the top are _exactly_ the same as for the base (e.g. ~ 145.0 for Base Cretaceous, not +-0.1) SUBSERIES GRAPHIC INDICATION - Starting 2018/07: Where ratified, these are indicated as thin lines to the right side of the Series column, and small font U/L, M, L/E indicators (see also the Descriptive text change log) - This differs from the way Subsystems are indicated (the Carboniferous Subsystems since long are incidated as full cells), for graphic reasons mainly. 2021/10 Indication added for Neogene (Pliocene, Miocene) Subseries (ratified 12/13-10-2020) 2020/01 Indication added for Pleistocene Subseries (ratified in parallel to GSSP Chibanian; 15/30-01-2020) 2018/07 Indication added for Holocene Subseries (ratified in parallel to GSSP) TYPE SETTING CHANGES 2019/05 Precambrian font switched to italics, after discussion in Precambrian subcommission, ICS and ICS executive. Also Graphic changes (see below). 2018/07 Holocene ratified Subseries and Stages: Stage names put in smaller font than others for reason of chart design continuity. Also added U/L, M and L/E to the left of the Series column to indicate ratified Subseries to exist for this Series. 2016/04 Upper and Middle Pleistocene: capitalized placeholder subseries names in Stages column set in italics rather than regular font ======================== Descriptive text: 2024/12 - Substantial change and reorganization of the descriptive text. Specific mention of systems deviating from GTS base reference is removed. GTS2012 mention replaced by GTS2020. 2024/12 - Edited paragraph 1 (includes the line on subseries abbreviation formerly in paragraph 2): Units of all ranks are in the process of being defined by Global Boundary Stratotype Section and Points (GSSP) for their lower boundaries, including those of the Archean and Proterozoic, long defined by Global Standard Stratigraphic Ages (GSSA). Ratified Subseries/Subepochs are abbreviated as U/L (Upper/Late), M (Middle) and L/E (Lower/Early). Italic fonts indicate informal units and placeholders for unnamed units. Previous versions and detailed information on ratified GSSPs are available at the website http://www.stratigraphy.org. The URL to this chart is provided below. 2024/12 - Edited paragraph 2: Numerical ages are subject to ongoing revision and do not define units in the Phanerozoic and the Ediacaran; only GSSPs do. For boundaries in the Phanerozoic without ratified GSSPs or without constrained numerical ages, an approximate numerical age (~) is provided. 2024/12 - Edited paragraph 3: Most numerical ages are taken from ‘A Geologic Time Scale 2020’ by Gradstein et al. (2020), but some ages differ as provided by the relevant ICS subcommissions, with advice from the Timescale Calibration subcommission. These are approved by the ICS executive as the current consensus. 2024/12 - Edited Credits and (c) lines: Chart drafted and maintained online by officers K.M. Cohen and N. Car. The chart is a product of collective work by all ICS members past and present. (c) International Commission on Stratigraphy, Month YYYY 2021/07 - Authorship of version of chart changed: N Car has taken over role of J.-X. Fan in 2020. 2018/07 - Authorship J.-X. Fan added to authors. 2016/10 - Authorship of version of chart changed: DAT Harper has taken over role of SC Finney in ICS executive board (as per 35th IGC Capetown ICS business-meeting and IUGS assembly) 2019/05 - Sentence added "Italic fonts indicate informal units and placeholders for unnamed units." 2018/07 - Sentence added "Ratified Subseries/Subepochs are abbreviated as U/L (Upper/Late), M (Middle) and L/E (Lower/Early)." TWO TIMES, IN FIRST PART AND IN SECOND PART of sentence declaring deviations from GTS2012: 2022/02 - Cambrian ages (base Cambrian) added 2018/07 - Lower Pleistocene changed into Quaternary: Q, upper Pg, C, T, P, PreC 2017/02 - upper Paleogene ages (ages deviating) added (2018/07: upper decapitalised) 2016/10 - reordered ammended the ages/subcommissions to be chronological (lower Pl, C, T, P, PreC) 2014/02 - Lower Pleistocene (ages deviating) added 2013 - Permian (ages deviating) added 2012 - Triassic and Cretaceous ones as deviating from 'A Geological Time Scale 2012' communicated status 2014/02 - To cite: Cohen et al. (2013) Episodes reference added. GRAPHICS =========== 2024/12 - Logo of CGMW/CCGM updated in lower right corner 2023/04: Cell thickness of Lower Cretaceous Aptian (thinner), Barremian (thinner), Hauteverian (thicker) and Valanginian (thicker) stages adapted Now visually compliant again to numeric age revisions (thickness was based on 2012 numeric age, thickness now is based on 2023 numeric ages) 2022/10: ICS bottom of chart signature at base Archean moved back to base Hadean (to indicate the now formalised status of the Hadean with the ratified GSSA). 2021/07: Stratigraphic colour for Pennsylvanian ammended (to contrast it to Bashkirian better), in collaboration with CCGM/CGMW (Bruno Vrielynck). 2021/05: Stratigraphic colour for Late Pleistocene and Holocene ammended, in collaboration with CCGM/CGMW. Cf. Table 2 in Head et al. (2020, Episodes). 2019/05: ICS bottom of chart signature moved from base Hadean to base Archean (to better indicate the informal status of Hadean) 2019/03: Cell widths of 'Precambrian' table column modified. 2019/05: Header placement above cell columns of 'Precambrian' table column modified. 'Eonothem / Eon', Erathem / Era and System / Period headers rotated to 45 degreees as the Phanerozoic table columns. The reason for the change was to remove unclarity, former placement was suggesting that it was the header for the Precambrian cell too (following aforementioned discussion). 2013/2015 - 'Systems' cells of first column slimmed down to match the width in the second and third column - Vertical and horizontal centering of names in their cells checked and fixed Adobe-illustrator file (main version layers): - Background layer (not displayed as visible) contained 'made invisible' logos from 2012 congres and sponsor. These are deleted now. - Added the deep URL in the lowerright corner of the chart. - Added a line 'The URL to this chart is found below.' to the first paragraph of the text. - line spacing of the blank lines set to 7 pt, wheras the main text is in 9 pt font. - further fiddiling with the exact font size of the text lines to accommodate additions with versions. Adobe-illustrator file (layers storing translations) - Since 2019, the master file for the english version of the chart, also holds additional layers with translated versions - Importing those from separate illustrator files (Graphic Officer archive) and PDFs (translations produced independently Graphic Officer; Chinese and Japanese fonts) is in progress. - This serves to be able to update translated versions more easily. - Some features are: --- Toggle numeric ages layer in decimal point notations, numeric ages layer in decimal comma notation, --- Logo and text space at bottom of chart to feature translating parties. --- Logo space also used to produce four-annual IGC handout versions of chart. Per 2023/10 the following translations have been imported in the master file (next to English): -- Finnish, Hungarian, Norwegian, Dutch (NL,B), Slovak, Czech, German, French [with decimal comma]; -- Turkish, Brazilian Portuguese, Iberian Portuguese, American Spanish, Spanish, Catalan, Chinese, Japanese, Korean [with decimal point]. -- At GBDB in China, a Chinese masterfile translated chart is kept, parallel to ICS. As per 2022/02-2023/10 older translations still awaiting import are: -- Russian, Lithuanian, Basque