GSSP Table - All Periods

Global Boundary Stratotype Section and Point (GSSP) of the International Commission on Stratigraphy


Numerical Age (Ma)

GSSP Location

Latitude, Longitude

Boundary Level

Correlation Events



Phanerozoic Eon

Cenozoic Era

Quaternary System

Holocene Series

Holocene Stage


NorthGRIP ice core, central Greenland

75.1000°N 42.3200°W

1492.45m depth in Borehole NGRIP2

Climatic -- End of the Younger Dryas cold spell, which is reflected in a shift in deuterium excess values

Ratified 2008

Episodes 31/2, 2008; < a href="/gssp/holocene.pdf">J. Quaternary Sci., Vol. 24 pp. 3-17, 2009

Pleistocene Series

Upper Stage








Middle Stage








Calabrian Stage


Vrica, Italy

39.0385°N 17.1348°E

base of the marine claystone overlying the sapropelic marker Bed 'e' (Mediterranean Precession Related Sapropel, MPRS 176)

Magnetic -- ~15 kyr after end of Olduvai (C2n) normal polarity chron

Ratified 1985 as base of Pleistocene; Ratified 2011 as base of Calabrian

Episodes 8/2, p. 116 - 120, 1985; Episodes 35/3, p. 388-397, 2012

Gelasian Stage


Monte San Nicola, Sicily, Italy

37.1469°N 14.2035°E

base of marly layer overlying sapropel MPRS 250

Magnetic -- Matuyama/Gauss boundary (C2r/C2An) is 1m below GSSP. GSSP level is within Marine Isotope Stage 103.

Ratified 1996 as base of Gelasian; Ratified 2009 as base of Pleistocene and Quaternary

Episodes 21/2, p. 82 - 87, 1998 Episodes 33/3, p. 152-158, 2010

Neogene System

Pliocene Series

Piacenzian Stage


Punta Piccola, Sicily, Italy

37.2889°N 13.4933°E

base of the beige marl bed of small-scale carbonate cycle 77 (MPRS 347)

Magnetic -- Gauss/Gilbert (C2An/C2Ar) magnetic reversal is recorded immediately above the GSSP

Ratified 1997

Episodes 21/2, p. 88 - 93, 1998

Zanclean Stage


Eraclea Minoa, Sicily, Italy

37.3917°N 13.2806°E

base of the Trubi Formation which corresponds to Insolation cycle 510

Magnetic -- base of the Thvera magnetic event (C3n.4n) is only 96 kyr (5 precession cycles) younger than the GSSP.

Ratified 2000

Episodes 23/3, p. 179 - 187, 2000

Miocene Series

Messinian Stage


Oued Akrech, Morocco

33.9369°N 6.8125°W

reddish layer of sedimentary cycle number 15

Planktonic foraminifer first regular occurrence of Globorotalia miotumida, and calcareous nannofossil FAD Amaurolithus delicatus

Ratified 2000

Episodes 23/3, p. 172 - 178, 2000

Tortonian Stage


Monte dei Corvi Beach, near Ancona, Italy

43.5867°N 13.5694°E

mid-point of sapropel layer of basic cycle number 76.

Calcareous nannofossil last common occurrence of Discoaster kugleri

Ratified 2003

Episodes 28/1, p. 6 - 17, 2005

Serravallian Stage


Ras il Pellegrin section, Fomm Ir- Rih Bay, west coast of Malta

35.9139°N 14.3361°E

formation boundary between the Globigerina Limestone and Blue Clay

Oxygen-isotopic event (global cooling episode) Mi3b; near calcareous nannofossil LAD of Sphenolithus heteromorphus

Ratified 2007

Episodes, 32/3, 152 - 166, 2009;

Langhian Stage


Potentially in astronomicallytuned ODP core (Leg 154) or in Italy (Moria or La Vedova )



Near planktonic foraminifer FAD of Praeorbulina glomerosa and top of magnetic polarity chronozone C5Cn.1n



Burdigalian Stage


Potentially in astronomicallytuned ODP core



Near planktonic foraminifer FAD of Globigerinoides altiaperturus or near top of magnetic polarity chronozone C6An



Aquitanian Stage


Lemme-Carrioso Section, Allessandria Province, Italy

44.6589°N 8.8364°E

35m from the top of the section

Magnetic -- base of Chron C6Cn.2n; planktonic foraminifer FAD of Paragloborotalia kugleri; calcareous nannofossil near LAD Reticulofenestra bisecta (base Zone NN1); Oxygen isotopic event Mi-1.

Ratified 1996

Episodes 20/1, p. 23 - 28, 1997

Paleogene System

Oligocene Series

Chattian Stage


Possibly Monte Cagnero, Umbria-Marche region, Italy



Potentially extinction of planktonic foraminifer Chiloguembelina (base Foram Zone P21b); or an isotopic/climatic event



Rupelian Stage


Massignano, near Ancona, Italy

43.5328°N 13.6011°E

base of a 0.5m thick greenishgrey marl bed 19m above base of section

Foraminifer LAD Hantkenina and Cribrohantkenina

Ratified 1992

Episodes 16/3, p.379 - 382, 2001

Eocene Series

Priabonian Stage


Alano section, Piave River; Veneto Prealps, Belluno province, N. Italy


Tiziano Bed

Calcareous nannofossil near FAD Chiasmolithus oamaruensis (base Zone NP18)



Bartonian Stage


Contessa highway section near Gubio, Central Apennines, Italy



Calcareous nannofossil near LAD Reticulofenestra reticulata



Lutetian Stage


Gorrondatxe section, Basque Country, Spain

43°22'46.47"N, 3°00'51.61"W

dark marl at 167.85 m in Gorrondatxe sea-cliff section

LO of calcareous nannofossil Blackites inflatus (CP12a/b boundary); middle of polarity Chron C21r

Ratified 2011

Episodes 34/2, p.86 - 108, 2011

Ypresian Stage


Dababiya, near Luxor, Egypt

25.5000°N 32.5311°E

Base of Bed 1 in DBH subsection

Carbon Isotope Excursion base, initiation of basal Eocene Thermal maximum ("PETM")

Ratified 2003

Micropaleontology 49/1, p.41 - 59, 2003; Episodes 30/4, p. 271 - 286, 2007

Paleocene Series

Thanetian Stage


Zumaia section, northern Spain

43.3006°N 2.2594°W

30.5m above the base of Itzurun Formation

Magnetic -- Base of Chron C26n

Ratified 2008

Episodes 34/4, p.220 - 243, 2011

Selandian Stage


Zumaia section, northern Spain

43.3006°N 2.2594°W

base of the red marls of Itzurun Formation

2nd radiation of the calcareous nannofossil group Fasciculithus and sea-level fall

Ratified 2008

Episodes 34/4, p.220 - 243, 2011

Danian Stage


Oued Djerfane, west of El Kef, Tunisia

36.1537°N 8.6486°E

reddish layer at the base of the 50cm thick, dark boundary clay

Iridium geochemical anomaly. Associated with a major extinction horizon (dinosaurs, ammonites, foraminifers, etc.)

Ratified 1991

Episodes 29/4, p. 263 - 278, 2006

Mesozoic Era

Cretaceous System

Upper Cretaceous Series

Maastrichtian Stage


Tercis les Bains, Landes, France

43.6795°N 1.1133°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, p. 229 - 238, 2001

Campanian Stage


candidates are in southern England and in Texas



Crinoid LAD Marsupites testudinarius



Santonian Stage

86.3 ± 0.5

Olazagutia, Navarra, Spain

42.8668°N 2.1968°W

94.4 m in the Cantera de Margas quarry section

the FO of the inoceramid bivalve Platyceramus undulatoplicatus

Ratified 2013

Episodes 37/1, p. 2 - 13, 2014

Coniacian Stage

89.8 ± 0.3

candidates are in Poland (Slupia Nadbrzena), USA (Pueblo, Colorado), and Germany (Salzgitter-Sadler Quarry)



Inoceramid bivalve FAD Cremnoceramus rotundatus (sensu Tröger non Fiege)



Turonian Stage


Pueblo, Colorado, USA

38.2822°N 104.7275°W

base of Bed 86 of the Bridge Creek Limestone Member

Ammonite FAD Watinoceras devonense

Ratified 2003

Episodes 28/2,p. 93 - 104, 2005

Cenomanian Stage


Mount Risou, Hautes-Alpes, France

44.3925°N 5.5119°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, p. 21 - 32, 2004

Lower Cretaceous Series

Albian Stage


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



Aptian Stage


candidate is Gorgo a Cerbara, Piobbico, Umbria-Marche, central Italy



Magnetic -- base of Chron M0r; near FAD of Paradeshayesites oglanlensis ammonite zone



Barremian Stage


candidate is Río Argos near Caravaca, Murcia Province, Spain



Ammonite FAD Spitidiscus hugii - Spitidiscus vandeckii group



Hauterivian Stage


candidate is La Charce village, Drôme Province, southeast France



Ammonite FAD of genus Acanthodiscus (especially A. radiatus)



Valanginian Stage


candidates are near Montbrunles- Bains (Drôme province, SE France) and Cañada Luenga (Betic Cordillera, S. Spain)



Calpionellid FAD Calpionellites darderi (base of Calpionellid Zone E); followed by ammonite FAD "Thurmanniceras" pertransiens



Berriasian Stage





Candidates include: (1) Magnetic -- base of Chron M18r, (2) Base of Calpionellid zone B, (3) ammonite FAD of Berriasella jacobi



Jurassic System

Upper Jurassic Series

Tithonian Stage

152.1 ± 0.9

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 Chron M22An



Kimmeridgian Stage

157.3 ± 1.0

candidate is Flodigarry (Isle of Skye, NW Scotland)

57.6000°N 6.2000°W


Ammonite near base of Pictonia baylei ammonite zone of Boreal realm

Anticipated 2009


Oxfordian Stage

163.5 ± 1.0

candidates are Redcliff Point (Dorset, SW England) and Savouron (Provence, SE France)



Ammonite Cardioceras redcliffense Horizon at base of the Cardioceras scarburgense Subzone (Quenstedtoceras mariae Zone)



Middle Jurassic Series

Callovian Stage

166.1 ± 1.2

candidates are Pfeffingen (Swabian Alb, SW Germany) and in Russia



Ammonite FAD of the genus Kepplerites (Kosmoceratidae)

 (defines base of Macrocephalites herveyi Zone in sub-Boreal province of Great Britain to southwest Germany)



Bathonian Stage

168.3 ± 1.3

Ravin du Bès, Bas-Auran area, Alpes de Haute Provence, France

43.9606°N 6.3153°E

base of limestone bed RB07

Ammonite FAD Gonolkite convergens (defines base of Zigzagiceras zigzag Zone)

Ratified 2008

Episodes 32/4, p. 222 - 248, 2009

Bajocian Stage

170.3 ± 1.4

Murtinheira Section, Cabo Mondego, Portugal

40.1992°N 8.9042°W

base of Bed AB 11

Ammonite FAD Hyperlioceras mundum, Hyperlioceras furcatum, Braunsina aspera, and Braunsina elegantula

Ratified 1996

Episodes 20/1, p.16 - 22, 1997

Aalenian Stage

174.1 ± 1.0

Fuentelsaz, Spain

41.1708°N 1.8333°W

base of Bed FZ 107

Ammonite FAD Leioceras opalinum and Leioceras lineatum

Ratified 2000

Episodes 24/3, p.166 - 175, 2001

Lower Jurassic Series

Toarcian Stage

182.7 ± 0.7

Peniche (Portugal)

39.3708ºN 9.3853ºW

base of bed 15e (Couches de passage), uppermost Lemede Formation

FO of the ammonite D. (E.) simplex co-occurring with D. (E.) pseudocommune and D. (E.) polymorphum .

Ratified 2014


Pliensbachian Stage

190.8 ± 1.0

Wine Haven, Robin Hood's Bay, Yorkshire Coast, England

54.4069°N 0.4975°W

base of Bed 73b

Ammonite association of Bifericeras donovani and Apoderoceras sp.

Ratified 2005

Episodes 29/2, p. 93 - 106, 2006

Sinemurian Stage

199.3 ± 0.3

East Quantoxhead, SW England

51.1909°N 3.2364°W

0.90 m above the base of Bed 145

Ammonite FAD Vermiceras quantoxense, Vermiceras palmeri

Ratified 2000

Episodes 25/1, p. 22-28, 2002

Hettangian Stage

201.3 ± 0.2

Kuhjoch section, Tyrol, Austria

47.4839°N 11.5306°E

5.80 m above top of Koessen Formation

FO of ammonite Psiloceras spelae tirolicum, FO of aragonitic foraminifer Praegubkinella turgescens

Ratified 2010

Episodes 36/3, p. 162-198, 2013

Triassic System

Upper Triassic Series

Rhaetian Stage


Key sections in Austria, British Columbia (Canada), and Turkey



Near FAD of ammonite Cochloceras, conodonts Misikella spp. and Epigondolella mosheri, and radiolarian Proparvicingula moniliformis



Norian Stage


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



Carnian Stage


Prati di Stuores, Dolomites, Italy

46.5269°N 11.9303°E

base of marly limestone bed SW4, 45m from base of San Cassiano Formation

FAD of the ammonoid Daxatina canadensis; just below FO of conodont Paragondolella polygnathiformis and base of normal-polarity magnetic zone S2n

Ratified 2008

Episodes 35/3, p. 414 - 430, 2012

Middle Triassic Series

Ladinian Stage


Bagolino, Province of Brescia, Northern Italy

45.8193°N 10.4710°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, p. 233 - 244, 2005

Anisian Stage


Candidate section at Desli Caira (Dobrogea, Romania); significant sections in Guizhou Province (China) and South Primorye (Russia)

45.0742°N 28.8022°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 polarity MT1n

Anticipated 2009

Albertiana 36, 2007.

Lower Triassic Series

Olenekian Stage


Candidate GSSP Mud (Muth) village, Spiti valley, northwest India

31.9654°N 78.0246°E

base of Bed 13A-2, about 4.8m up in Mikin Formation., Section M04 (~4000 m elevation

Conodont FAD 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 2009

Albertiana 36, 2007

Induan Stage

252.17 ± 0.06

Meishan, Zhejiang Province, China

31.0798°N 119.7058°E

base of Bed 27c in the Meishan D Section

Conodont FAD Hindeodus parvus

Ratified 2001

Episodes 24/2, p. 102 - 114, 2001

Paleozoic Era

Permian System

Lopingian Series

Changhsingian Stage

254.14 ± 0.07

Meishan, Zhejiang Province, China

31.0819°N 119.7064°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, p. 175-182, 2006

Wuchiapingian Stage

259.8 ± 0.4

Penglaitan, Guanxi Province, South China

23.6953°N 109.3211°E

base of Bed 6k in the Penglaitan Section

Conodont FAD Clarkina postbitteri postbitteri

Ratified 2004

Episodes 29/4, p. 253-262, 2006

Guadalupian Series

Capitanian Stage

265.1 ± 0.4

Nipple Hill, SE Guadalupe Mountains, Texas, U.S.A

31.9091°N 104.7892°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 Stage

268.8 ± 0.5

Guadalupe Pass, Texas, U.S.A

31.8658°N 104.8328°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 Stage

272.3 ± 0.5

Stratotype Canyon, Texas, U.S.A

31.8767°N 104.8768°W

42.7m above the base of the Cutoff Formation

Conodont FAD Jinogondolella nankingensis

Ratified 2001


Cisuralian Series

Kungurian Stage

283.5 ± 0.6

candidates are in southern Ural Mtns.



Near conodont FAD Neostreptognathus pnevi - N. exculptus

Anticipated 2009


Artinskian Stage

290.1 ± 0.26

candidates are in southern Ural Mtns.



Conodont FAD Sweetognathus whitei

Anticipated 2009


Sakmarian Stage

295.0 ± 0.18

candidate is at Kondurovsky, Orenburg Province, Russia.



Near conodont FAD Sweetognathus merrelli

Anticipated 2009


Asselian Stage

298.9 ± 0.15

Aidaralash Creek, Kazakhstan

50.2458°N 57.8914°E

27m above the base of Bed 19, Aidaralash Creek

Conodont FAD of isolated-nodular morphotype of Streptognathodus "wabaunsensis"

Ratified 1996

Episodes 21/1, p. 11-18, 1998

Carboniferous System

Pennsylvanian Subsystem (series Classification Approved In 2004)

Upper Pennsylvanian Series

Gzhelian Stage

303.7 ± 0.1

candidates are in southern Urals or Nashui (south China).



Conodont FAD Idiognathodus simulator (s.str.). Close to FAD of ammonoid Shumardites.



Kasimovian Stage

307.0 ± 0.1

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.



Middle Pennsylvanian Series

Moscovian Stage

315.2 ± 0.2

candidates are in southern Urals or Nashui (south China).



Either conodont FAD Idiognathoides postsulcatus or Declinognathodus donetzianus.



Lower Pennsylvanian Series

Bashkirian Stage

323.2 ± 0.4

Arrow Canyon, Nevada

36.7333°N 114.7778°W

82.9m above the top of the Battleship Formation in the lower Bird Spring Formation

Conodont FAD Declinognathodus noduliferus

Ratified 1996

Episodes 22/4, p. 272-283, 1999

Mississippian Subsystem

Upper Mississippian Series (series Classification Approved In 2004)

Serpukhovian Stage

330.9 ± 0.2

candidates are Verkhnyaya Kardailovka (Urals) or Nashui (China)



Conodont FAD Lochriea ziegleri



Middle Mississippian Series

Visean Stage

346.7 ± 0.4

Pengchong, south China

24.4333°N 109.4500°E

base of bed 83 in the Pengchong Section

Benthic Foraminifer FAD Eoparastaffella simplex

Ratified 2008

Episodes 26/2, p. 105 - 115, 2003

Lower Mississippian Series

Tournaisian Stage

358.9 ± 0.4

La Serre, France

43.5555°N 3.3573°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 biostratigraphic problems, and can not be correlated with precision.)

Ratified 1990

Episodes 14/4, p. 331-336, 1991; Newsletters on Stratigraphy, 43/2, p. 195 - 205, 2009

Devonian System

Upper Devonian Series

Famennian Stage

372.2 ± 1.6

Coumiac Quarry, near Cessenon, Montagne Noire, France

43.4613°N 3.0403°E

Base of Bed 32a

Conodont FAD Palmatolepis triangularis, just above a major extinction horizon (Kellwasser Event) with conodont LADs Ancyrodella and Ozarkodina, and Goniatite LADs of Gephuroceratidae and Beloceratidae

Ratified 1993

Episodes 16/4, p. 433-441, 1993



382.7 ± 1.6

Col du Puech de la Suque, Montage Noire, France

43.5032°N 3.0868°E

base of Bed 42' at Col du Puech de la Suque section E

Conodont FAD Ancyrodella rotundiloba

Ratified 1986

Episodes 10/2, p. 97-101, 1987

Middle Devonian Series

Givetian Stage

387.7 ± 0.8

Jebel Mech Irdane, Morocco

31.2374°N 4.3541°W

base of Bed 123

Conodont FAD Polygnathus hemiansatus

Ratified 1994

Episodes 18/3, p. 107-115, 1995

Eifelian Stage

393.3 ± 1.2

Wetteldorf, Eifel Hills, Germany

50.1496°N 6.4716°E

21.25m above the base of the exposed section, base of sample station WP30

Conodont FAD Polygnathus costatus partitus

Ratified 1985

Episodes 8/2, p. 104-109, 1985

Lower Devonian Series

Emsian Stage

407.6 ± 2.6

Zinzil'ban Gorge in the Kitab State Geological Reserve, Uzbekistan

39.2000°N 67.3056°E

base of Bed 9/5

Conodont FAD Polygnathus kitabicus

Ratified 1995

Episodes 20/4, p. 235-240, 1997

Pragian Stage

410.8 ± 2.8

Velká Chuchle, Prague, Czech Republic

50.0147°N 14.3726°E

base of Bed 12 in Velká Chuchle Quarry

Conodont FAD Eognathodus sulcatus sulcatus and Latericriodus steinachensis Morph beta

Ratified 1989

Episodes 12/2, p. 109-113, 1989

Lochkovian Stage

419.2 ± 3.2

Klonk, near Prague, Czech Republic

49.8550°N 13.7920°E

within Bed 20

Graptolite FAD Monograptus uniformis

Ratified 1972

IUGS Series A, 5, p. 96-109, 1977

Silurian System

Přídolí Series

423.0 ± 2.3

Požáry Section, Reporyje, Prague, Czech Republic

50.0277°N 14.3249°E

within Bed 96

Graptolite FAD Monograptus parultimus

Ratified 1984

Episodes 8/2, p. 101-103, 1985; Geol. Series, Nat. Mus. Wales, 9, p. 90 - 100, 1989

Ludlow Series

Ludfordian Stage

425.6 ± 0.9

near Ludlow, UK

52.3592°N 2.7772°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, p. 21-23, 1982; Geol. Series, Nat. Mus. Wales, 9, p. 73 - 90, 1989

Gorstian Stage

427.4 ± 0.5

near Ludlow, UK

52.3592°N 2.7772°W

coincident with the base of the Lower Elton Formation

Graptolite FAD Saetograptus (Colonograptus) varians

Ratified 1980

Lethaia 14; Episodes 5/3, p. 21-23, 1982; Geol. Series, Nat. Mus. Wales, 9, p. 73 - 90, 1989

Wenlock Series

Homerian Stage

430.5 ± 0.7

Sheinton Brook, Homer, UK

52.6156°N 2.5647°W

within upper part of the Apedale Member of the Coalbrookdale Formation

Graptolite FAD Cyrtograptus lundgreni

Ratified 1980

Lethaia 14; Episodes 5/3, p. 21-23, 1982; Geol. Series, Nat. Mus. Wales, 9, p. 51-73, 1989

Sheinwoodian Stage

433.4 ± 0.8

Hughley Brook, UK

52.5811°N 2.6389°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, p. 21-23, 1982; Geol. Series, Nat. Mus. Wales, 9, p. 51-73, 1989

Llandovery Series

Telychian Stage

438.5 ± 1.1

Cefn-cerig Road Section, Wales, UK

51.9700°N 3.7900°W

within the Wormwood Formation

Just above Brachiopod LAD Eocoelia intermedia and below FAD of Eocoelia curtisi

Ratified 1984

Episodes 8/2, p. 101-103, 1985; Geol. Series, Nat. Mus. Wales, 9, p. 36-50, 1989

Aeronian Stage

440.8 ± 1.2

Trefawr Track Section, Wales, UK

52.0300°N 3.7000°W

within Trefawar Formation

Graptolite FAD Monograptus austerus sequens

Ratified 1984

Episodes 8/2, p. 101-103, 1985; Geol. Series, Nat. Mus. Wales, 9, p. 36-50, 1989

Rhuddanian Stage

443.8 ± 1.5

Dob's Linn, Scotland

55.4400°N 3.2700°W

1.6m above the base of the Birkhill Shale Formation

Graptolite FAD Akidograptus ascensus

Ratified 1984

Episodes 8/2, p. 101-103, 1985; Silurian Times No. 14 (2006)

Ordovician System

Upper Ordovician Series

Hirnantian Stage

445.2 ± 1.4

Wangjiawan North section, N of Yichang city, Western Hubei Province, China

30.9841°N 111.4197°E

0.39m below the base of the Kuanyinchiao Bed

Graptolite FAD Normalograptus extraordinarius

Ratified 2006

Episodes 29/3, p. 183-196, 2006

Katian Stage

453.0 ± 0.7

Black Knob Ridge Section, Atoka, Oklahoma (USA)

34.4305°N 96.0746°W

4.0m above the base of the Bigfork Chert

Graptolite FAD Diplacanthograptus caudatus

Ratified 2006

Episodes 30/4, p. 258-270, 2007

Sandbian Stage

458.4 ± 0.9

Sularp Brook, Fågelsång, Sweden

55.7137°N 13.3255°E

1.4m below a phosphorite marker bed in the E14b outcrop

Graptolite FAD Nemagraptus gracilis

Ratified 2002

Episodes 23/2, p. 102-109, 2000

Middle Ordovician Series

Darriwilian Stage

467.3 ± 1.1

Huangnitang section, Changshan, Zhejiang Province, SE China

28.8539°N 118.4897°E

base of Bed AEP 184

Graptolite FAD Undulograptus austrodentatus

Ratified 1987

Episodes 20/3, p. 158-166, 1997

Dapingian Stage

470.0 ± 1.4

Huanghuachang Section, NE of Yichang city, Hubei Province, S. China

30.8605°N 110.3740°E

10.57 m above base of the Dawan Formation

Conodont FAD of Baltoniodus triangularis

Ratified 2007

Episodes 28/2, p. 105 - 117, 2005; Episodes 32/2, p. 96-113, 2009

Lower Ordovician Series

Floian Stage

477.7 ± 1.4

Diabasbrottet, Hunneberg, Sweden

58.3589°N 12.5024°E

in the lower Tøyen Shale, 2.1m above the top of the Cambrian

Graptolite FAD Tetragraptus approximatus

Ratified 2002

Episodes 27/4, p. 265-272, 2004

Tremadocian Stage

485.4 ± 1.9

Green Point Section, western Newfoundland

49.6829°N 57.9653°W

at the 101.8m level, within Bed 23, in the measured section

Conodont FAD Iapetognathus fluctivagus

Ratified 2000

Episodes 24/1, p. 19 - 28, 2001

Cambrian System

Furongian Series

Stage 10


candidate section is Duibian (Zhejiang province, China)



Trilobite FAD of Lotagnostus americanus. An internal substage division might be FAD of Codylodus adesei conodont



Jiangshanian Stage


Duibian B section, Zhejiang province, China

28°48.958'N 118°36.896'E

28.2 m in Duibian B section

FAD of agnostid trilobite Agnostotes orientalis and the FO of polymerid trilobite Irvingella angustilimbata

Ratified 2011

Episodes 35/4, p.462-477, 2012

Paibian Stage


Wuling Mountains, Huayuan County, NW Hunan Province, Chin

28.3895°N 109.5257°E

at 396 m in the Huaqiao Formation

Trilobite FAD Glyptagnostus reticulatus

Ratified 2003

Lethaia 37, p. 365-379, 2004

Series 3

Guzhangian Stage


Louyixi, Guzhang County, NW Hunan Province, S. China

28.7200°N 109.9647°E

121.3 m above the base of the Huaqiao Formation

Trilobite FAD Lejopyge laevigata

Ratified 2008

Episodes 32/1, p.41-55, 2009

Drumian Stage


Drum Mountains, Millard County, Utah, USA

39.5117°N 112.9915°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,p. 85-95, 2007

Stage 5


candidate sections are Wuliu-Zengjiayan (east Guizhou, China) and Split Mountain (Nevada, USA)



Trilobite, potentially FAD of Oryctocephalus indicus



Series 2

Stage 4





Trilobite FAD Olenellus or Redlichia



Stage 3





Trilobites -- their FAD



Terreneuvian Series

Stage 2





Small Shelly Fossils, or Archaeocyathid species



Fortunian Stage

541.0 ± 1.0

Fortune Head, SE Newfoundland, Canada

47.0762°N 55.8310°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, p. 95-100, 1994


Proterozoic Eon

Neoproterozoic Era

Ediacaran System


Enorama Creek, Flinders Ranges, South Australia

31.3314°S 138.6334°E

base of the Marinoan cap carbonate

(1) rapid decay of Marinoan ice sheets and onset of distinct cap carbonates throughout the world, and (2) the beginning of a distinctive pattern of secular changes in carbon isotopes.

Ratified 1990

Lethaia 39, p.13- 30, 2006

Cryogenian System


Defined chronometrically; but will be replaced by GSSP. First glacial episode occurred after 750 Ma




Ratified 1990

Episodes 14/2,1991

Tonian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Mesoproterozoic Era

Stenian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Ectasian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Calymmian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Paleoproterozoic Era

Statherian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Orosirian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Rhyacian System


Defined chronometrically




Ratified 1990

Episodes 14/2,1991

Siderian System


Defined chronometrically, but it will be replaced by GSSP




Ratified 1990

Episodes 14/2,1991

Archean Eon

Neoarchean Era


Defined chronometrically




Subcomm. decision 1996, but not submitted to ICS

Informally in Episodes 15/2, 1992

Mesoarchean Era


Defined chronometrically




Subcomm. decision 1996, but not submitted to ICS

Informally in Episodes 15/2, 1992

Paleoarchean Era


Defined chronometrically




Subcomm. decision 1996, but not submitted to ICS

Informally in Episodes 15/2, 1992

Eoarchean Era


Base is not defined




Subcomm. decision 1996, but not submitted to ICS

Informally in Episodes 15/2, 1992

Hadean Eon





Formation of planet Earth. Informal term