GSSP Table

Cenozoic Mesozoic Paleozoic Precambrian


Status on 2008, compiled by Jim Ogg (Chair SSI) and Gabi Ogg (Secretary)

Age (Ma) CGTS 2008
GSSP Location
Latitude, Longitude
Boundary Level
Correlation Events
Holocene Series 0.0117 NorthGRIP ice core, central Greenland 75.10°N 42.32°W 1492.45m depth in Borehole NGRIP2 End of the Younger Dryas cold spell, which is reflected in a shift in deuterium excess values Ratified 2008 Episodes 31/2, 2008
Upper Pleistocene (Tarantian) 0.126 Amsterdam-Terminal borehole, Netherlands 52°22'45"N 4°54'52"E  63.5 m below surface Base of warm marine isotope stage 5e, before final glacial episode of Pleistocene. Anticipated 2008  
Middle Pleistocene (Ionian) 0.781 Candidate sections in Italy (Montalbano Jorica or Valle di Manche) and Japan (Chiba)     Magnetic -- Brunhes-Matuyama magnetic reversal (base of Chron 1n) Anticipated 2008  
Calabrian 1.806 Vrica, Italy 39°02'18.61"N  17°08'05.79"E base of the marine claystone overlying the sapropelic marker Bed 'e' ~15 kyr after end of Olduvai normal polarity chron Ratified 1985 Episodes 8/2, 1985
Gelasian (currently in Pliocene) 2.588 Monte San Nicola, Sicily, Italy 37°08'48.8"N  14°12'12.6"E* base of marly layer overlying sapropel MPRS 250 with an age of 2.588 Ma precessional cycle 250 from the present, Marine Isotope Stage 103, with an age of  2.588 Ma Ratified 1996 Episodes 21/2, 1998
Piacenzian 3.600 Punta Piccola, Sicily, Italy 37°17'20"N  13°29"36"E* base of the beige marl bed of small-scale carbonate cycle 77 with an age of 3.6Ma precessional excursion 347 from the present with an astrochronological age estimate of 3.600 Ma Ratified 1997 Episodes 21/2, 1998
Zanclean 5.332 Eraclea Minoa, Sicily, Italy 37°23'30"N  13°16'50"E base of the Trubi Formation Insolation cycle 510 counted from the present with an age of 5.33Ma Ratified 2000 Episodes 23/3, 2000
Messinian 7.246 Oued Akrech, Morocco 33°56'13"N  6°48'45"W reddish layer of sedimentary cycle number 15 first regular occurrence of planktonic foraminifer Globorotalia miotumida and the FAD of the calcareous nannofossil Amaurolithus delicatus Ratified 2000 Episodes 23/3, 2000
Tortonian 11.61 Monte dei Corvi Beach, near Ancona, Italy 43°35'12"N  13°34'10"E mid-point of sapropel layer of basic cycle number 76. Last Common Occurrences of the calcareous nannofossil Discoaster kugleri and the planktonic foraminifer Globigerinoides subquadratus Ratified 2003 Episodes 28/1, 2005
Serravallian 13.82 Ras il Pellegrin section, Fomm Ir-Rih Bay, west coast of Malta 35°54'50"N  14°20'10"E formation boundary between the Globigerina Limestone and Blue Clay Mi3b oxygen-isotopic event (global cooling episode); near LAD of calcareous nannofossil Sphenolithus heteromorphus Ratified 2006  
Langhian 15.97 Potentially in astronomically-tuned ODP core (Leg 154) or in Italy (Moria or La Vedova )     Near FAD of planktonic foraminifer Praeorbulina glomerosa and top of magnetic polarity chronozone C5Cn.1n Anticipated 2008  
Burdigalian 20.43 Potentially in astronomically-tuned ODP core     Near FAD of planktonic foraminifer Globigerinoides altiaperturus or near top of magnetic polarity chronozone C6An Anticipated 2008  
Aquitanian (base Neogene) 23.03 Lemme-Carrioso Section, Allessandria Province, Italy 44°39'32"N  08°50'11"E 35m from the top of the section Base of magnetic polarity chronozone C6Cn.2n; FAD of planktonic foraminifer Paragloborotalia kugleri; near extinction of calcareous nannofossil Reticulofenestra bisecta (base Zone NN1); Oxygen isotopic event Mi-1. Ratified 1996 Episodes 20/1, 1997
Chattian 28.40 Possibly Monte Cagnero, Umbria-Marche region, Italy     Potentially extinction of planktonic foraminifer Chiloguembelina (base Foram Zone P21b); or an isotopic/climatic event Anticipated 2008  
Rupelian 33.9 Massignano, near Ancona, Italy 43°31'58.2"N  13°36'03.8"E* base of a 0.5m thick greenish-grey marl bed 19m above base of section Foraminifer LAD Hantkenina and Cribrohantkenina Ratified 1992 Episodes 16/3, 2001
Priabonian 37.2 Alano section, Piave River; Veneto Prealps, Belluno province, N. Italy   Tiziano Bed Near FAD of calcareous nannofossil Chiasmolithus oamaruensis (base Zone NP18) Anticipated 2008  
Bartonian 40.4 Contessa highway section near Gubio, Central Apennines, Italy     Near extinction of calcareous nannofossil Reticulofenestra reticulata Anticipated 2008  
Lutetian 48.6 candidate is Agost section, Murcia province, Betic Cordilleras, Spain     Planktonic foraminifer FAD of Hantkenina Anticipated 2008  
Ypresian 55.8 Dababiya, near Luxor, Egypt 25°30'N  32°31'52"E** Base of Bed 1 in DBH subsection base of the Carbon Isotope Excursion (CIE) Ratified 2003 Micropaleontology 49/1, 2003
Thanetian 58.7 Zumaia section, northern Spain 43º18’02”N 2º15’34”W   Magnetic polarity chronozone, base of C26n Ratified 2008  
Selandian 61.1  Zumaia section, northern Spain 43º18’02”N 2º15’34”W Base of the red marls of Itzurun Formation Onset of a carbon isotope shift and sea-level drop Ratified 2008  
Danian (base Paleogene) 65.5 Oued Djerfane, west of El Kef, Tunisia 36°09'13.2"N  8°38'54.8"E reddish layer at the base of the 50cm thick, dark boundary clay Iridium geochemical anomaly. Associated with a major extinction horizon (foraminifers, calcareous nannofossils, dinosaurs, etc.) Ratified 1991 Episodes 29/4, 2006
Age (Ma) CGTS 2008
GSSP Location
Latitude, Longitude
Boundary Level
Correlation Events
Late Cretaceous
Maastrichtian 70.6 Tercis les Bains, Landes, France 43°40'46.1"N  1°06'47.9"W* level 115.2 on platform IV of the geological site at Tercis les Bains Mean of 12 biostratigraphic criteria of equal importance. Closely above is FAD of ammonite Pachydiscus neubergicus. Boreal proxy is FAD of belemnite Belemnella lanceolata. Ratified 2001 Episodes 24/4, 2001
Campanian 83.5 candidates are in southern England and in Texas     Crinoid, extinction of Marsupites testudinarius Anticipated 2008  
Santonian 85.8 Leading candidates are Olazagutia (Spain) and Ten-Mile Creek (Texas)     Inoceramid bivalve, FAD of Cladoceramus undulatoplicatus Anticipated 2008  
Coniacian 89.3 Leading candidates are in Poland (Slupia Nadbrzena), USA (Pueblo, Colorado), and Germany (Salzgitter-Salder Quarry)     Inoceramid bivalve, FAD of Cremnoceramus rotundatus (sensu Tröger non Fiege) Anticipated 2008  
Turonian 93.6 Pueblo, Colorado, USA 38°16'56"N  104°43'39"W* base of Bed 86 of the Bridge Creek Limestone Member Ammonite FAD Watinoceras devonense Ratified 2003 Episodes 28/2, 2005
Cenomanian 99.6 Mount Risou, Hautes-Alpes, France 44°23'33"N  5°30'43"E 36 meters below the top of the Marnes Bleues Formation on the south side of Mont Risou Planktonic foraminifer  FAD Rotalipora globotruncanoides Ratified 2002 Episodes 27/1, 2004
Early Cretaceous
Albian 112.0 Southeastern France     Candidates include: (1) calcareous nannofossil, FAD of Praediscosphaera columnata (= P. cretacea of some earlier studies), (2) carbon-isotope excursion (black-shale episode), (3) ammonite Anticipated 2008  
Aptian 125.0 candidate is Gorgo a Cerbara, Piobbico, Umbria-Marche, central Italy     Magnetic polarity chronozone, base of M0r; near base of Paradeshayesites oglanlensis ammonite zone Anticipated 2008  
Barremian 130.0 candidate is Río Argos near Caravaca, Murcia Province, Spain     Ammonite, FAD of Spitidiscus hugii – Spitidiscus vandeckii group Anticipated 2008  
Hauterivian 133.9 candidate is La Charce village, Drôme Province, southeast France     Ammonite, FAD of genus Acanthodiscus (especially  A. radiatus) Anticipated 2008  
Valanginian 140.2 candidates are near Montbrun-les-Bains (Drôme province, SE France) and Cañada Luenga (Betic Cordillera, S. Spain)     Calpionellid, FAD of Calpionellites darderi (base of Calpionellid Zone E); followed by the FAD of ammonite “Thurmanniceras” pertransiens Anticipated 2008  
Berriasian (base Cretaceous) 145.5       Maybe near FAD of ammonite Berriasella jacobi Anticipated 2009  
Late Jurassic
Tithonian 150.8 candidates are Mt. Crussol or Canjuers (SE France) and Fornazzo (Sicily, S. Italy)     Near base of Hybonoticeras hybonotum ammonite zone and lowest occurrence of Gravesia genus, and the base of magnetic polarity chronozone M22An Anticipated 2008  
Kimmeridgian 155.6 candidate is Flodigarry (Isle of Skye, NW Scotland)     Ammonite, near base of Pictonia baylei ammonite zone of Boreal realm Anticipated 2008  
Oxfordian 161.2 candidates are Savouron (Provence, SE France) and Redcliffe Point (Dorset, SW England)     Ammonite Cardioceras redcliffense Horizon at base of the Cardioceras scarburgense Subzone (Quenstedtoceras mariae Zone) Anticipated 2008  
Middle Jurassic
Callovian 164.7 candidate is Pfeffingen, Swabian Alb, SW Germany     Ammonite, FAD of the genus Kepplerites (Kosmoceratidae) (defines base of Macrocephalites herveyi Zone in sub-Boreal province of Great Britain to southwest Germany) Anticipated 2008  
Bathonian 167.7 Ravin du Bès, Bas-Auran area, Alpes de Haute Provence, France 43°57'38"N  6°18'55"E* base of limestone bed RB07 Ammonite, FAD of Gonolkite convergens (defines base of Zigzagiceras zigzag Zone) Ratified 2008  
Bajocian 171.6 Murtinheira Section, Cabo Mondego, Portugal 40°11'57"N  8°54'15"W* base of Bed AB11 of the Murtinheira Section Ammonite FAD Hyperlioceras mundum, H. furcatum, Braunsina aspera, B. elegantula Ratified 1996 Episodes 20/1, 1997
Aalenian 175.6 Fuentelsaz, Spain 41°10'15"N  1°50'W base of Bed FZ 107 in Fuentelsaz Section Ammonite FAD Leioceras opalinum and Leioceras lineatum Ratified 2000 Episodes 24/3, 2001
Early Jurassic
Toarcian 183.0 Peniche (Portugal)     Ammonite, near FAD of a diversified Eodactylites ammonite fauna; correlates with the NW European Paltus horizon. Anticipated 2008  
Pliensbachian 189.6 Robin Hood's Bay, Yorkshire Coast, England 54°24'25"N   0°29'51"W base of Bed 73b at Wine Haven, Robin Hood’s Bay ammonite association of Bifericeras donovani and Apoderoceras sp. Ratified 2005 Episodes 29/2, 2006
Sinemurian 196.6 East Quantoxhead, SW England 51°11'27.3"N  3°14'11.2"W* 0.90 m above the base of Bed 145 Ammonite FAD Vermiceras quantoxense, Vermiceras palmeri Ratified 2000 Episodes 25/1, 2002
Hettangian (base Jurassic) 199.6 candidate is Kuhjoch section, Tyrol, Austria     FAD of first species (Psiloceras spelae) of Psiloceras ammonite group; significantly above a sharp negative carbon-isotope excursion Anticipated 2008  
Late Triassic
Rhaetian 203.6 Key sections in Austria, British Columbia (Canada), and Turkey     Near FAD of ammonite Cochloceras, conodonts Misikella spp. and Epigondolella mosheri, and radiolarian Proparvicingula moniliformis Anticipated 2008  
Norian 216.5 Candidates are Black Bear Ridge in British Columbia (Canada) and  Pizzo Mondello, Sicily (Italy)     Base of Stikinoceras kerri ammonoid zone and near FAD of Metapolygnathus echinatus within the M. communisti conodont zones Anticipated 2008  
Carnian 228.7 Prati di Stuores, Dolomites, Italy. Important reference sections in Spiti (India) and New Pass, Nevada (USA). 46°31'37"N 11°55'49"E base of marly limestone bed SW4, 45m from base of San Cassiano Formation Near FADs of the ammonoid Daxatina, the conodont "Paragondolella" polygnathiformis and Halobia bivalves. Just above base of S2n magnetic polarity zone and above the maximum flooding surface of Sequence Lad 3 of Hardenbol et al (1998). Ratified 2008? Albertiana 36, 2007
Middle Triassic
Ladinian 237.0 Bagolino, Province of Brescia, Northern Italy 45°49'09.5"N  10°28'15.5"E base of a 15 – 20cm thick limestone bed overlying a distinctive groove (“Chiesense groove”) of limestone nodules in a shaly matrix, located about 5m above the base of the Buchenstein Beds Ammonite FAD Eoprotrachyceras curionii (base of the E. curionii zone). Conodont  FAD Budurovignathus praehungaricus is in the uppermost Anisian. Ratified 2005 Episodes 28/4, 2005
Anisian 245.9 Candidate section at Desli Caira (Dobrogea, Romania); significant sections in Guizhou Province (China) and South Primorye (Russia) 45°04'27"N 28°48'08"E In Section B, the GSSP level will be either the FAD of conodont Chiosella timorensis at the base of Bed GR7 at ca. 7 m; OR the base of magnetozone MT1n at the 5.7 m level. Conodont  FAD Chiosella timorensis  or Magnetic -- base of magnetic normal-polarity chronozone MT1n Anticipated 2008 Albertiana 36, 2007.
Early Triassic
Olenekian 249.5 Candidate GSSP Mud (Muth) village, Spiti valley, northwest India 31°57'55.5"N 78°01'28.5"E base of Bed 13A-2, about 4.8m up in Mikin Formation., Section M04 (~4000 m elevation Conodont FAD of Neospathodus waageni, just above base of Rohillites rohilla ammonite zone, and below lowest occurrence of Flemingites and Euflemingites ammonite genera.  Within a prominent positive Carbon-13 peak, and just above widely recognizable sequence boundary. Anticipated 2008 Albertiana 36, 2007.
Induan (base Triassic) 251.0 Meishan, Zhejiang Province, China 31° 4'47.28"N  119°42'20.90"E base of Bed 27c in the Meishan Section Conodont FAD Hindeodus parvus Ratified 2001 Episodes 24/2, 2001
Age (Ma) CGTS 2008
GSSP Location
Latitude, Longitude
Boundary Level
Correlation Events
Changhsingian 253.8 Meishan, Zhejiang Province, China 31° 4'55"N  119°42'22.9"E base of Bed 4a-2, 88 cm above the base of the Changxing Limestone at the Meishan D Section Conodont FAD Clarkina wangi Ratified 2005 Episodes 29/3, 2006
Wuchiapingian 260.4 Penglaitan, Guanxi Province, South China 23°41"43"N  109°19"16"E base of Bed 6k in the Penglaitan Section Conodont FAD Clarkina postbitteri postbitteri Ratified 2004 Episodes 29/4, 2006
Capitanian 265.8 Nipple Hill, SE Guadalupe Mountains, Texas, U.S.A 31°54'32.8"N  104°47'21.1"W 4.5m above the base of the outcrop section of the Pinery Limestone Member of the Bell Canyon Formation Conodont FAD Jinogondolella postserrata Ratified 2001  
Wordian 268.0 Guadalupe Pass, Texas, U.S.A 31°51'56.9"N  104°49'58.1"W 7.6m above the base of the Getaway Ledge outcrop section of the Getaway Limestone member of the Cherry Canyon Formation Conodont FAD Jinogondolella aserrata Ratified 2001  
Roadian 270.6 Stratotype Canyon, Texas, U.S.A 31°52'36.1"N  104°52'36.5"W 42.7m above the base of the Cutoff Formation Conodont FAD Jinogondolella nankingensis Ratified 2001  
Kungurian 275.6 candidates are in southern Ural Mtns.     Near conodont FAD Neostreptognathus pnevi - N. exculptus Anticipated 2008  
Artinskian 284.4 candidates are in southern Ural Mtns.     Conodont FAD Sweetognathus whitei Anticipated 2008  
Sakmarian 294.6 candidate is at Kondurovsky, Orenburg Province, Russia.     Near conodont FAD Sweetognathus merrelli Anticipated 2008  
Asselian (base Permian) 299.0 Aidaralash Creek, Kazakhstan 50°14'45"N  57°53'29"E* 27m above the base of Bed 19, Aidaralash Creek Conodont FAD of isolated-nodular morphotype of Streptognathodus "wabaunsensis" Ratified 1996 Episodes 21/1, 1998
Gzhelian 303.4 Candidates are in southern Urals or Nashui (south China).     Conodont FAD Idiognathodus simulator (s.str.). Close to FAD of ammonoid Shumardites. Anticipated 2008  
Kasimovian 307.2 Candidates are in southern Urals, southwest USA and Nashui (south China).     Fusulinid FAD Protriticites, which is near ammonoid FAD Eothalossoceras.  Alternative (higher) base is fusulinid FAD Montiparus montiparus, which is near conodont FAD Idiognathodus sagittalis.  Age given here is the higher version; the lower one is about 1 myr older. Anticipated 2008  
Moscovian 311.7 Candidates are in southern Urals or Nashui (south China).     Either conodont FAD Idiognathoides postsulcatus or Declinognathodus donetzianus. Anticipated 2009  
Bashkirian 318.1 Arrow Canyon, Nevada 36°44’00” N, 114°46’40” W** 82.9m above the top of the Battleship Formation in the lower Bird Spring Formation Conodont FAD Declinograptus noduliferous Ratified 1996 Episodes 22/4, 1999
Serpukhovian 328.3 Candidates are Verkhnyaya Kardailovka  (Urals) or Nashui (China)     Conodont FAD Lochriea ziegleri Anticipated 2008  
Visean 345.3 Pengchong, south China 24°26’N,   109°27’E base of bed 83 in the Pengchong Section Foraminifer, lineage Eoparastaffella simplex morphotype 1/morphotype 2 Ratified 2008  
Tournaisian (base Carboniferous) 359.2 La Serre, France 43°33'19.9"N  3°21'26.3"E* base of Bed 89 in Trench E’ at La Serre, (but FAD now known to be at base of Bed 85) Conodont FAD Siphonodella sulcata IMPRECISE (GSSP discovered in 2006 to have biostrat problems, and can not be correlated wih precision.) Ratified 1990 Episodes 14/4, 1991; Kölner Forum Geol. Paläont., 15, 2006
Late Devonian
Famennian 374.5 Coumiac Quarry,  near Cessenon, Montagne Noire, France 43°27'40.6"N  3°02'25"E* Base of Bed 32a Conodont FAD Palmatolepis subperlobata and flood occurrence of Palmatolepis ultima Ratified 1993 Episodes 16/4, 1993
Frasnian 385.3 Col du Puech de la Suque, Montage Noire, France 43°30'11.4"N  3°05'12.6"E* base of Bed 42’ at Col du Puech de la Suque section E Conodont FAD Ancyrodella rotundiloba Ratified 1986 Episodes 10/2, 1987
Middle Devonian
Givetian 391.8 Jebel Mech Irdane, Morocco 31°14'14.7"N  4°21'14.8"W* base of Bed 123 Conodont FAD Polygnathus hemiansatus Ratified 1994 Episodes 18/3, 1995
Eifelian 397.5 Wetteldorf, Eifel Hills, Germany 50°08'58.6"N  6°28'17.6"E* 21.25m above the base of the exposed section, base of unit WP30 Conodont FAD Polygnathus costatus partitus Ratified 1985 Episodes 8/2, 1985
Early Devonian
Emsian 407.0 Zinzil'ban Gorge, Uzbekistan 39°12'N  67°18'20"E base of Bed 9/5 in the Zinzil’ban Gorge in the Kitab State Geological Reserve Conodont FAD Polygnathus kitabicus Ratified 1995 Episodes 20/4, 1997
Pragian 411.2 Velká Chuchle, Prague, Czech Republic 50°00'53"N  14°22'21.5"E* base of Bed 12 in Velká Chuchle Quarry Conodont FAD Eognathodus sulcatus sulcatus or, better, of Latericriodus steinachensis Morph beta Ratified 1989 Episodes 12/2, 1989
Lochkovian (base Devonian) 416.0 Klonk, near Prague, Czech Republic 48.855°N  13.792°E** within Bed 20 Graptolite FAD Monograptus uniformis Ratified 1972 IUGS Series A, 5, 1977
Pridoli (Epoch) 418.7 Pozáry Section, Reporyje, Prague, Czech Republic 50°01'39.82"N  14°19'29.56"E* within Bed 96 Graptolite FAD Monograptus parultimus Ratified 1984 Episodes 8/2, 1985; Geol. Series, Nat. Mus. Wales 9, 1989
Ludfordian 421.3 near Ludlow, UK 52°21'33"N  2°46'38"W* coincident with the base of the Leintwardine Formation Imprecise. May be near base of Saetograptus leintwardinensis graptolite zone. Ratified 1980 Lethaia 14; Episodes 5/3,  1982; Geol. Series, Nat. Mus. Wales 9, 1989
Gorstian 422.9 near Ludlow, UK 52°21'33"N  2°46'38"W* coincident with the base of the Lower Elton Formation Graptolite FAD Saetograptus (Colonograptus) varians Ratified 1980 Lethaia 14; Episodes 5/3,  1982; Geol. Series, Nat. Mus. Wales 9, 1989
Homerian 426.2 Sheinton Brook, Homer, UK 52°36'56"N  2°33'53"W* within upper part of the Apedale Member of the Coalbrookdale Formation Graptolite FAD Cyrtograptus lundgreni Ratified 1980 Lethaia 14; Episodes 5/3,  1982; Geol. Series, Nat. Mus. Wales 9, 1989
Sheinwoodian 428.2 Hughley Brook, UK 52°34'52"N  2°38"20"W* base of the Buildwas Formation Imprecise.  Between the base of acritarch biozone 5 and LAD of conodont Pterospathodus amorphognathoides.  The current GSSP does not coincide with the base of the Cyrtograptus centrifugus Biozone, as was supposed when the GSSP was defined.  Restudy  recommends a slightly higher and correlatable level on condonts -- the Ireviken  datum 2, which coincides approximately with the base of the  murchisoni graptolite biozone Ratified 1980 Lethaia 14; Episodes 5/3,  1982; Geol. Series, Nat. Mus. Wales 9, 1989
Telychian 436.0 Cefn-cerig Road Section, Wales, UK 51.97°N  3.79°W** within the Wormwood Formation Just above LAD of Brachiopod Eocoelia intermedia and below FAD of Eocoelia curtisi Ratified 1984 Episodes 8/2, 1985; Geol. Series, Nat. Mus. Wales 9, 1989
Aeronian 439.0 Trefawr Track Section, Wales, UK 52.03°N  3.70°W** within Trefawar Formation Graptolite FAD Monograptus austerus sequens Ratified 1984 Episodes 8/2, 1985; Geol. Series, Nat. Mus. Wales 9, 1989
Rhuddanian (base Silurian) 443.7 Dob's Linn, Scotland 55.44°N  3.27°W** 1.6m above the base of the Birkhill Shale Formation Graptolite FAD Akidograptus ascensus Ratified 1984 Episodes 8/2, 1985
Late Ordovician
Hirnantian 445.6 Wangjiawan North section, N of Yichang city, Western Hubei Province, China 30°59'2.68"N  111°25'10.76"E 0.39m below the base of the Kuanyinchiao Bed Graptolite FAD Normalograptus extraordinarius Ratified 2006 Episodes 29/3, 2006
Katian 455.8 Black Knob Ridge Section,  Atoka, Oklahoma (USA) 34°25'49.74"N   96°4'28.38"W 4.0m above the base of the Bigfork Chert Graptolite FAD Diplacanthograptus caudatus Ratified 2006 Episodes 30/4, 2007
Sandbian 460.9 Sularp Brook, Fagelsang, Sweden 55°42'49.3"N  13°19'31.8"E* 1.4m below a phosphorite marker bed in the E14b outcrop Graptolite FAD Nemagraptus gracilis Ratified 2002 Episodes 23/2, 2000
Middle Ordovician
Darriwilian 468.1 Huangnitang section, Changshan, Zhejiang Province, SE China 28°51'14"N  118°29'23"E* base of Bed AEP 184 Graptolite FAD Undulograptus austrodentatus Ratified 1987 Episodes 20/3, 1997
Dapingian 471.8 Huanghuachang section, NE of Yichang city, Hubei Province, S, China 30°51’ 37.8’’N 110°22’ 26.5’’E 10.57 m above base of the Dawan Formation Conodont FAD of Baltoniodus triangularis Ratified 2007 Proposal in Episodes 28/2, 2005
Early Ordovician
Floian 478.6 Diabasbrottet, Hunneberg, Sweden 58°21'32.2"N  12°30'08.6"E in the lower Tøyen Shale, 2.1m above the top of the Cambrian Graptolite FAD Tetragraptus approximatus Ratified 2002 Episodes 27/4,  2004
Tremadocian (base Ordovician) 488.3 Green Point Section, western Newfoundland 49°40'58.5"N  57°57'55.09"W* at the 101.8m level, within Bed 23, in the measured section Conodont FAD Iapetognathus fluctivagus Ratified 2000 Episodes 24/1, 2001
Stage 10 492 candidate section is Duibian (Zhejiang province, China)     Trilobite FAD of Lotagnostus americanus. An internal substage division might be FAD of Codylodus adesei conodont Anticipated 2009  
Stage 9 496 candidate sections at Duibian (Zhejiang province, China) and Gonggiri (Korea)     Trilobite FAD of  Agnostotes orientalis Anticipated 2008  
Paibian 499 Wuling Mountains, Huayuan County, NW Hunan Province, China 28°23.37'N  109°31.54'E at 396 m in the Huaqiao Formation Trilobite FAD Glyptagnostus reticulatus Ratified 2003 Lethaia 37,  2004
Epoch 3
Guzhangian 503 Louyixi, Guzhang County, NW Hunan Province, S. China 28°43.20’ N; 109°57.88’ E 121.3 m above the base of the Huaqiao Formation Trilobite FAD Lejopyge laevigata Ratified 2008  
Drumian 506.5 Drum Mountains, Millard County, Utah, USA 39°30.705'N  112°59.489'W at the base of a dark-gray thinly laminated calcisiltite layer, 62 m above the base of the Wheeler Formation Trilobite FAD Ptychagnostus atavus Ratified 2006 Episodes 30/2, 2007
Stage 5 510 candidate sections are Wuliu-Zengjiayan (east Guizhou, China) and Split Mountain (Nevada, USA)     Trilobite, potentially FAD of Oryctocephalus indicus Anticipated 2008  
Epoch 2
Stage 4 515       Trilobite, FAD of Olenellus or Redlichia Anticipated 2009  
Stage 3 521       Trilobites -- their FAD Anticipated 2009  
Stage 2 528       Small Shelly Fossils, or Archaeocyathid species    
Fortunian (base Cambrian) 542 Fortune Head, SE Newfoundland, Canada 47°4'34.47"N  55°49'51.71"W* 2.4m above the base of Member 2 in the Chapel Island Formation Trace fossil FAD Trichophycus pedum Ratified 1992 Episodes 17/1&2, 1994
Age (Ma) CGTS 2008
GSSP Location
Latitude, Longitude
Boundary Level
Correlation Events
Neoproterozoic Era
Ediacaran 635 Enorama Creek, Flinders Ranges, South Australia 31°19'53.2"S  138°38'0,2"E base of the Marinoan cap carbonate Beginning of a distinctive pattern of secular changes in carbon isotopes Ratified 2004 Lethaia 39,  2006
Cryogenian 850 Defined chronometrically; but will be replaced by GSSP. First glacial episode occurred after 750 Ma       Ratified 1990 Episodes 14/2,1991
Tonian 1000 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Mesoproterozoic Era
Stenian 1200 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Ectasian 1400 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Calymmian 1600 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Paleoproterozoic Era
Statherian 1800 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Orosirian 2050 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Rhyacian 2300 Defined chronometrically       Ratified 1990 Episodes 14/2,1991
Siderian 2500 Defined chronometrically, but it will be replaced by GSSP       Ratified 1990. GSSP replacement planned for 2009 Episodes 14/2,1991
Age (Ma) CGTS 2008
GSSP Location
Latitude, Longitude
Boundary Level
Correlation Events
Archean Eon
Neoarchean 2800 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15/2, 1992
Mesoarchean 3200 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15/2, 1992
Paleoarchean 3600 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15/2, 1992
Eoarchean ~4000 Base is not defined       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15/2, 1992