199 by K.M. Cohen1, S.C. Finney 2, P.L. Gibbard 3, and J.-X. Fan 4 The ICS International Chronostratigraphic Chart 1 Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands. E-mail: [email protected] 2 Department of Geological Sciences, California State University, Long Beach CA, USA. E-mail: [email protected] 3 Cambridge Quaternary, University of Cambridge, Cambridge, England, UK. E-mail: [email protected] 4 State Key Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology & Palaeontology, CAS, Nanjing, PR China. E-mail:[email protected] The International Commission on Stratigraphy (ICS) (IUGS) uses the units and formally defined boundaries as international has a long tradition of producing international charts standards: they are included in the library of GeoSciML, an application for globally accessing standards-based geoscience data and that communicate higher-order divisions of geological information. Furthermore, the GSSPs (Global Boundary Stratotype time and actual knowledge on the absolute numerical Section and Point) that define the boundaries are recognized as ages of their boundaries. The primary objective of ICS international geostandards, at which ICS encourages the placement is to define precisely a global standard set of time- of markers, educational exhibits, and even ‘golden spikes’ in well- correlative units (Systems, Series, and Stages) for attended dedication ceremonies (Schmitz et al., 2011: their Fig. 4; Morton, 2012). Here we present the most recently updated version stratigraphic successions worldwide. These units are, in of the ICS Chart dated January 2013 (Fig. 1). turn, the basis for the Periods, Epochs and Ages of the From earlier editions, we have continued the organisation of the Geological Time Scale. Setting an international global chart in four columns. Three columns present the Phanerozoic, standard is fundamental for expressing geological showing four systems in each column. At the lowest level they display 34 + 34 + 32 stages. The stage names are derived from stratotype knowledge. It is also of considerable pragmatic areas, and the stages are defined primarily on marine faces. The fourth importance as it provides the framework through which column shows the Precambrian, sub-divided to system level. An regional-scale higher-resolution divisions can be linked, innovation to the layout is that the stages of greater temporal duration equated and collated. This is a status update on the are shown with thicker intervals in the columns. The numerical ages International Chronostratigraphic Chart and the ICS make clear that the chronostratigraphic units are not of equal temporal duration and that the geological time scale is not a linear one. The website www.stratigraphy.org. three Phanerozoic columns span 145, 214 and 182 Ma respectively, but have equal heights in the chart. Within these columns, each stage Introduction is given a fixed proportion of the column height (e.g., 2%). The remaining height (100–(34 x 2) = 32% in the example) is then At the 34th International Geological Congress, in 2012 in Brisbane, distributed proportionally to the stages that cover more than the fixed over 6000 delegates found the redesigned International proportion on a linear timescale for that column. With the design we Chronostratigraphic Chart of the International Commission on have tried to communicate visually, in improved style, that the division Stratigraphy (ICS) in their conference packages. The ICS Chart is a of Phanerozoic geological time is irregular and governed by the hierarchy of chronostratigraphic units (e.g. Systems, Series, and stratigraphical successions on which the units were originally defined, Stages) on which geochronological units (e.g. Periods, Epochs, and to which many subsequent revisions have been made. The chart design Ages) are based. With the addition of calibrated numerical ages for is intended to be advantageous in the daily use for both professional unit boundaries it serves as the International Geological Timescale. geologists and other users alike. The ICS Chart caters to a range of users: geologists that are relatively new to a particular time-stratigraphic interval and seek to place named Global divisions and ‘Golden Spikes’ divisions in their correct order and hierarchical structure, professionals who need to look up the latest specific estimates of numerical ages, Units of all ranks are in the process of being defined by GSSPs earth science students at all levels, and the general public interested for their lower boundaries, including those of the Archean and in the long history of the Earth. For the International Commission on Proterozoic, the latter long defined by Global Standard Stratigraphic Stratigraphy, the chart is also important for communicating the Ages (GSSA). The status of each GSSP is displayed in the chart by progress in formalising a single set of global chronostratigraphic units small golden-spike icons at the base of the divisions that they define. defined by specific boundaries, and for communicating standards of The status of each GSSA is indicated similarly with clock icons. colour coding the divisions for use on geological maps and sections, For boundaries in the Phanerozoic for which no GSSP is currently using the scheme established by the Commission for the Geological ratified, or which lack constraining numerical ages, an approximate Map of the World (CGMW: www.ccgm.org ). Furthermore, the numerical age (~) is provided. Note that numerical ages do not define Commission on the Management and Application of Geoscience units in the Phanerozoic and the Ediacaran, they are only defined by Information (CGI) of the International Union of Geological Sciences GSSPs. Episodes Vol. 36, no. 3 200 201 INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2013/01 numerical numerical numerical Eonothem numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age Erathem / Era System / Period GSSP GSSP age (Ma) GSSP GSSA EonothemErathem / Eon System / Era / Period EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) / Eon GSSP age (Ma) present ~ 145.0 358.9 ± 0.4 ~ 541.0 ±1.0 Holocene Ediacaran 0.0117 Tithonian Upper 152.1 ±0.9 Famennian ~ 635 0.126 Upper Kimmeridgian Neo- Cryogenian Middle 157.3 ±1.0 Upper proterozoic Pleistocene 0.781 372.2 ±1.6 850 Calabrian Oxfordian Tonian 1.806 163.5 ±1.0 Frasnian 1000 Callovian 166.1 ±1.2 Quaternary Gelasian 382.7 ±1.6 Stenian 2.588 Bathonian 168.3 ±1.3 Piacenzian Middle Bajocian Givetian 1200 Pliocene 3.600 170.3 ±1.4 Middle 387.7 ±0.8 Meso- Zanclean Aalenian proterozoic Ectasian 5.333 174.1 ±1.0 Eifelian 1400 Messinian Jurassic 393.3 ±1.2 7.246 Toarcian Calymmian Tortonian 182.7 ±0.7 Emsian 1600 11.62 Pliensbachian Statherian Serravallian Lower 407.6 ±2.6 13.82 190.8 ±1.0 Lower 1800 Miocene Pragian 410.8 ±2.8 Langhian Sinemurian Proterozoic Neogene Orosirian 15.97 199.3 ±0.3 Lochkovian Paleo- Hettangian 2050 Burdigalian 201.3 ±0.2 419.2 ±3.2 proterozoic 20.44 Mesozoic Rhaetian Pridoli Rhyacian Aquitanian 423.0 ±2.3 23.03 ~ 208.5 Ludfordian 2300 Cenozoic Chattian Ludlow 425.6 ±0.9 Siderian 28.1 Gorstian Oligocene Upper Norian 427.4 ±0.5 2500 Rupelian Wenlock Homerian 430.5 ±0.7 Precambrian Neo- 33.9 ~ 227 Sheinwoodian 433.4 ±0.8 archean 2800 Priabonian Carnian Silurian Devonian Telychian 38.0 ~ 237 Llandovery 438.5 ±1.1 Meso- Bartonian Triassic 41.3 Ladinian Aeronian 440.8 ±1.2 archean Eocene Middle ~ 242 Rhuddanian Lutetian Anisian 443.4 ±1.5 3200 47.8 247.2 Hirnantian 445.2 ±1.4 Paleo- Olenekian 251.2 Ypresian Lower Katian Archean archean Paleogene Induan 252.17 ±0.06 Upper 56.0 Changhsingian 453.0 ±0.7 3600 Thanetian 254.14 ±0.07 59.2 Lopingian Sandbian Eo- Wuchiapingian Paleozoic Paleocene Selandian 259.8 ±0.4 458.4 ±0.9 archean Phanerozoic Phanerozoic Phanerozoic 61.6 Capitanian Darriwilian 4000 Danian 265.1 ±0.4 Middle 66.0 467.3 ±1.1 Guadalupian Wordian Dapingian Hadean Maastrichtian 268.8 ±0.5 470.0 ±1.4 Roadian Ordovician ~ 4600 72.1 ±0.2 272.3 ±0.5 Floian Campanian Kungurian Lower 477.7 ±1.4 Units of all ranks are in the process of being defined by Global 283.5 ±0.6 Tremadocian Boundary Stratotype Section and Points (GSSP) for their lower 83.6 ±0.2 Permian Santonian 485.4 ±1.9 boundaries, including those of the Archean and Proterozoic, long Upper 86.3 ±0.5 Artinskian defined by Global Standard Stratigraphic Ages (GSSA). Charts and Cisuralian 290.1 ±0.26 Stage 10 Coniacian ~ 489.5 detailed information on ratified GSSPs are available at the website 89.8 ±0.3 Sakmarian http://www.stratigraphy.org. The URL to this chart is found below. 295.0 ±0.18 Furongian Jiangshanian Turonian ~ 494 Asselian Numerical ages are subject to revision and do not define units in 93.9 298.9 ±0.15 Paibian ~ 497 Cenomanian Gzhelian Guzhangian the Phanerozoic and the Ediacaran; only GSSPs do. For boundaries 100.5 Upper 303.7 ±0.1 ~ 500.5 in the Phanerozoic without ratified GSSPs or without constrained Kasimovian 307.0 ±0.1 numerical ages, an approximate numerical age (~) is provided. Paleozoic Series 3 Drumian Albian ~ 504.5 Middle Moscovian Numerical ages for all systems except Permian,Triassic, Cretaceous ~ 113.0 315.2 ±0.2 Stage 5 Mesozoic and Precambrian are taken from ‘A Geologic Time Scale 2012’ by Cretaceous ~ 509 Aptian Lower Bashkirian Stage 4 Gradstein et al. (2012); those for the Permian, Triassic and Pennsylvanian 323.2 ±0.4 Cretaceous were provided by the relevant ICS subcommissions. ~ 125.0 Series 2 ~ 514 Upper Serpukhovian Cambrian Stage 3 Barremian 330.9 ±0.2 Lower ~ 129.4 ~ 521 Hauterivian Coloring followsfollows the the Commission Commission for for the the ~ 132.9 Middle Visean Stage 2 Geological MapMap of of the the World.