Global Boundary Stratotype Section and Points

Global Boundary Stratotype Sections and Points (GSSPs) are reference points on stratigraphic sections of rock which define the lower boundaries of stages on the International Chronostratigraphic Chart. The boundary is defined by a spike in a rock succession coincident with available biological and other markers. Since 1977, the ICS has maintained the international GSSP register.

Rules

A geologic section has to fulfill a set of criteria to be adapted as a GSSP by the ICS. The following list summarizes the criteria where the imperative words SHOULD and MUST are defined according to RCF2119:

  1. A GSSP section MUST contain a stratigraphic marker that recognizes the lower boundary of a geologic Stage
  2. The boundary MUST be recognized by an observable, unambiguous change in the physical properties or fossil content of the strata, for example the first appearance datum of a fossil species
    • There SHOULD be other physical manifestations (secondary markers) that can be used to locate the boundary, e.g. other fossils, chemical changes, geomagnetic reversal
    • The section in which the marker appears SHOULD have layers containing minerals that can be radiometrically dated to assign ages to the depositional events at or bracketing the boundary horizon
    • The primary or secondary marker events MUST be manifested in regional and global stratigraphic sections to allow correlation in outcrops of the same age
    • The markers should be independent of facies
  3. The outcropping stratigraphic section containing the GSSP marker MUST have adequate thickness to support global correlation
  4. Sedimentation in the section containing the boundary must MUST be continuous without any changes in facies
  5. The section containing the marker SHOULD be unaffected by tectonic and sedimentary movements, and metamorphism
  6. The section containing the marker must MUST be accessible to research and free to access
    • The section containing the marker SHOULD be located where it can be visited quickly and SHOULD be kept in good condition (ideally a national reserve), in accessible terrain, extensive enough to allow repeated sampling and open to researchers of all nationalities
  7. The fossil content in the boundary interval SHOULD be abundant, distinctive, well preserved, and represent a fauna and/or flora as cosmopolitan and as diverse as possible.
  8. In order to ensure its acceptance and use in the Earth sciences, a boundary stratotype SHOULD contain as many specific marker horizons or other attributes as possible favorable for long-distance correlation.

Locations

GSSPs are spread throughout the world. The map below indicates each's approximate location.

Click on the [ ] icon for full-screen map

GSSP Tables

Quaternary

SubSeries Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Cenozoic Erathem
Quaternary System
Holocene Series
Upper Meghalayan Stage 4,250 yr b2k (before 2000 CE) Mawmluh Cave, Meghalaya, India 25°15'44''N; 91°42'54''E depth 7.45 mm in the speleothem KM-A Climatic - 4.2 ka event Ratified 2018

Episodes 2018; 41: 213-223. (PDF)

Middle Northgrippian Stage 8,236 yr b2k (before 2000 CE) North Greenland Ice Core Project, core NGRIP1, central Greenland ice sheet 75.1000°N 42.3200°W 1228.67 m in the NGRIP1 ice core Climatic – 8.2 ka event Ratified 2018

Episodes 2018; 41: 213-223. (PDF)

Lower Greenlandian Stage 11,700 yr b2k (before 2000 CE) North Greenland Ice Core Project, core NGRIP2, central Greenland ice sheet 75.1000°N 42.3200°W 1492.45 m in the NGRIP2 ice core Climatic - End of the Younger Dryas Chron which is reflected in an abrupt shift to lower deuterium excess values Holocene GSSP ratifed 2008; Lower Holocene Subseries and Greenlandian Stage ratified: 2018

Episodes 2008; 31: 264–267

Episodes 2018; 41: 213-223. (PDF)

Pleistocene Series
Upper Upper Stage GSSP presently undefined but provisionally dated at ~129 ka GSSP not presently defined - - Provisionally climatic – Marine Isotope Substage 5e Ratified in name only 2020 Head, M.J., Pillans, B., and Zalasiewicz, J.A., [submitted 2020]
Middle Chibanian Stage 0.7741 Chiba section, Japan 35.2943°N 140.1465°E lower boundary of the Byk-E tephra bed Magnetic - GSSP is 1.1 m below the directional midpoint of the Matuyama/Brunhes paleomagnetic reversal and occurs immediately below the top of Marine Isotope Substage (MIS) 19c. Ratified 2020 Episodes 2021; 44:317-347. (PDF)

GSSP has one SABS: 40.2910°N, 16.5518°E Ideale Section, Montalbano Jonico succession, Basilicata, S Italy SABS holds high-resolution C and O stratigraphy and a sapropel bed through Termination IX and MIS 19c; peaking 10Be/9Be ratio at the Matuyama/Brunhes boundary interval; regional tephra beds. SABS ratified 2023 Episodes, forthcoming
Lower Calabrian Stage 1.80 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 - ∼8m below the observed top of the Olduvai (C2n) normal polarity subchron. GSSP level coincides with the transition from MIS 65 to 64 Ratified 1985 as base of Pleistocene; Ratified 2011 as base of Calabrian Episodes 1985; 8:116-120; Episodes 2012; 35: 388-397
Head, M.J., 2019
Gelasian Stage 2.58 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 between ~0 and ~3 m above GSSP (Head, 2019) not ∼1 m (20 kyr) below it as reported by Rio et al. (1994, 1998). GSSP level is within Marine Isotope Stage 103. Ratified 1996 as base of Gelasian; Ratified 2009 as base of Pleistocene and Quaternary

Episodes 1998; 21: 82-87

Episodes 2010; 33: 152-158

Quaternary Sci. 2019; 500: 32-51,

Neogene

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Cenozoic Erathem
Neogene System
Pliocene Series
Piacenzian Stage 3.6 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 1998; 21: 88-93
Zanclean Stage 5.333 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 2000; 23: 179-187
Miocene Series
Messinian Stage 7.246 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 2000; 23: 172-178
Tortonian Stage 11.63 Monte dei Corvi Beach, near Ancona, Italy 43.587292°N, 13.5661724°E mid-point of sapropel layer of basic cycle number 76. Calcareous nannofossil last common occurrence of Discoaster kugleri Ratified 2003 Episodes 2005; 28: 6-17
Serravallian Stage 13.82 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 2009; 32: 152-166;
Langhian Stage 15.98 'Lower La Vedova Beach' section, near Ancona, Italy 43.59193°N, 13.56229°E Mid-point of the darker marly interval above 'Megabed IV' Closely to the top of magnetic polarity chronozone C5Cn.1n. Ratified 2023 Episodes forthcoming
Burdigalian Stage 20.44 Potentially in astronomicallytuned ODP core     Near planktonic foraminifer FAD of Globigerinoides altiaperturus or near top of magnetic polarity chronozone C6An    
Aquitanian Stage 23.03 Lemme-Carrosio 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 1997; 20: 23-28

Paleogene

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Cenozoic Erathem
Paleogene System
Oligocene Series
Chattian Stage 28.1 Monte Cagnero, Umbria-Marche region, Italy 43°38'47.81"N 12°28'03.83"E Highest common occurrence (HCO) of Chiloguembelina cubensis Oxygen isotope excursion possibly related to the Oi2a glaciation event Ratified 2016 Episodes, 41 (1): 17-32.
Rupelian Stage 33.9 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 2001; 16: 379-382
Eocene Series
Priabonian Stage 37.8 Alano section, Piave River; Veneto Prealps, Belluno province, N. Italy 45°54'51.10"N 11°55'4.87"E The base of a prominent crystal tuff layer, the Tiziano bed, at meter 63.57 Extinction of large acarininids and Morozovelloides crassatus; the Base of common and continuous Cribrocentrum erbae and the Top of Chiasmolithus grandis; the Base of Chron C17n and Subchron C17n.2n Ratified 2020 Episodes 2021; 44(2): 151-173
Bartonian Stage 41.2 Contessa highway section near Gubio, Central Apennines, Italy     Calcareous nannofossil near LAD Reticulofenestra reticulata    
Lutetian Stage 47.8 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 2011; 34: 86-108
Ypresian Stage 56.0 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 2007; 30: 271-286
Paleocene Series
Thanetian Stage 59.2 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 2011; 34: 220-243
Selandian Stage 61.6 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 2011; 34: 220-243
Danian Stage 66.0 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 2006; 29: 263-278

Cretaceous

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Mesozoic Erathem
Cretaceous System
Upper Cretaceous Series
Maastrichtian Stage 72.1±0.2 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 2001; 24: 229-238
Campanian Stage 82.7 - 84.5 1.4 km NNE from the town of Gubbio, central Italy 43.36267°N, 12.58283°E Level 221.53 m in the Bottaccione Gorge section at Gubbio, Umbria-Marche Basin, Italy The magnetic polarity reversal from Chron 34n (top of the Long Cretaceous Normal Polarity-Chron) to Chron C33r. Ratified 2022 Episodes 2023; 1st February

DOI: 10.18814/epiiugs/2022/022048
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 2014; 37: 2-13
Coniacian Stage 89.8 ± 0.3 Salzgitter-Salder, Lower Saxony, Germany 52.1243°N, 10.3295°E base of Bed 46 in the Salzgitter-Salder section first occurrence of the inoceramid Cremnoceramus deformis erectus Ratified 2021 Episodes 2022; 42(2): 181-220 DOI: 10.18814/epiiugs/2021/021022
Turonian Stage 93.9 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 2005; 28: 93-104
Cenomanian Stage 100.5 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 2004; 27: 21-32
Lower Cretaceous Series
Albian Stage ~113.0 Col de Pré-Guittard, Department of Drôme, southeastern France 44°30'28.3"N, 5°17'50.1"E 37.4 m above the base of the section and 0.4 m above the base of the laminated Niveau Kilian bed Lowest occurrence of the planktonic foraminifer Microhedbergella renilaevis Ratified 2016 Episodes 40/3, p. 177-188, 2017
Aptian Stage ~125.0 candidate is Gorgo a Cerbara, Piobbico, Umbria-Marche, central Italy     Magnetic - base of Chron M0r; near FAD of Paradeshayesites oglanlensis ammonite zone    
Barremian Stage 125.77 Río Argos section near Caravaca, Murcia Province, Spain 38.0704°N 1.9484°W base of Bed 171 FAD of ammonite species Taveraidiscus hugii (Spitidiscus hugii - Spitidiscus vandeckii group), within calcareous nannofossil Subzone NC5C and in the lowermost part of polarity chron M3r. Ratified 2023 Episodes, forthcoming
Hauterivian Stage ~132.9 La Charce, Department of Drôme, southeastern France 44°28'10.0"N, 5°26'37.4"E base of bed 189 in the La Charce section First occurrence of the ammonite genus Acanthodiscus which marks the base of the Acanthodiscus radiatus ammonite Zone Ratified 2019 Episodes 2021; 44(2): 129-150
Valanginian Stage ~139.8 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 ~145.0       Candidates include: (1) Magnetic - base of Chron M18r, (2) Base of Calpionellid zone B, (3) ammonite FAD of Berriasella jacobi    

Jurassic

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Mesozoic Erathem
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 Flodigarry, Isle of Skye, NW Scotland 57.6610°N 6.2455°W   Base of Subboreal ammonite Baylei Zone, Base of Densicostata Subzone marked by the base of the flodigarriensis horizon; Base of Boreal ammonite Bauhini Zone. Ratified 2021 Episodes 2023; 46(2): 281-307
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 2009; 32: 222-248
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 1997; 20: 16-22
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 2001; 24: 166-175
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 Episodes 2016; 39(3): 460-481
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 2006; 29: 93-106
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 2002; 25: 22-28
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 2013; 36: 162-198

Triassic

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Mesozoic Erathem
Triassic System
Upper Triassic Series
Rhaetian Stage ~208.5 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 ~227 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 ~237 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 2012; 35: 414-430
Middle Triassic Series
Ladinian Stage ~242 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 2005; 28: 233-244
Anisian Stage 247.2 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 251.2 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 2001; 24: 102-114

Permian

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
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 259.51 ± 0.21 Penglaitan, Guanxi Province, South China 23.6953°N 109.3211°E base of Bed n6L in the newly exposed Penglaitan section Conodont FAD
Clarkina postbitteri
Ratified 2004, Redefinition ratified 2023 Episodes 29/4 p. 253-262. 2006;
Episodes, in press (2023)
Guadalupian Series
Capitanian Stage 264.28 ± 0.16 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 Permophiles 34 p. 3-11, 1999;
Episodes 45/3 p. 309-331. 2022
Wordian Stage 266.9 ± 0.4 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 Permophiles 34 p. 3-11, 1999;
Wu et al. 2020 Palaeogeography Palaeoclimatology Palaeoecology 548 109668
Roadian Stage 273.01 ± 0.14 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 Permophiles 34 p. 3-11, 1999;
Shen et al. 2020- Earth-Sci Rev 211 103412
Cisuralian Series
Kungurian Stage 283.5 ± 0.6 Candidate is Rockland, Nevada       Anticipated 2024  
Artinskian Stage 290.1 ± 0.26 Dalny Tulkas section, Southern Ural Mts, Russia 53.88847°N 56.51615°E 0.6m above the base of bed 4b at the Dal'ny Tulkas section in the southern Urals of Russia Conodont FAD
Sweetognathus asymmetricus
Ratified 2022 Episodes 46/4, p. 623-651. 2023
Sakmarian Stage 293.52 ± 0.17 Usolka section, Southern Ural Mts, Russia 53.9247°N 56.7287°E 55.4 m (Bed 26/3) in the Usolka section Conodont FAD
Mesogondolella monstra
Ratified 2018 Episodes 43/4, 961-979, 2020
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 Streptognathodus isolatus Ratified 1996 Episodes 21/1, 11-18, 1998

Carboniferous

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
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. Stage 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 1999; 22: 272-283
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 2003; 26: 105-115
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 1991; 14: 331-336; Newsletters on Stratigraphy 2009; 43: 195-205

Devonian

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
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 1993; 16: 433-441
Frasnian Stage 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 1987; 10: 97-101
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 1995; 18: 107-115
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 1985; 8: 104-109
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 1997; 20: 235-240
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 1989; 12: 109-113
Lochkovian Stage 419.2 ± 3.2 Klonk, near Prague, Czech Republic 49.9008°N 14°0611°E within Bed 20 Graptolite FAD Monograptus uniformis Ratified 1972

The Geologic Time Scale 2020

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

Newsletters on Stratigraphy 25, 115–125

Facies 26, 35–54

Silurian

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
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 1985; 8: 101-103; 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 1982; 5: 21-23; Geol. Series, Nat. Mus. Wales 1989; 9: 73-90
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 1982; 5: 21-23; Geol. Series, Nat. Mus. Wales 1989; 9: 73-90
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 1982; 5: 21-23; Geol. Series, Nat. Mus. Wales 1989; 9: p. 51-73
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 1982; 5: 21-23; Geol. Series, Nat. Mus. Wales 1989; 9: p. 51-73
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 1985; 8: 101-103; Geol. Series, Nat. Mus. Wales 1989; 9: 36-50
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 1985; 8: 101-103; Geol. Series, Nat. Mus. Wales 1989; 9: 36-50
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 1985; 8: 101-103; Silurian Times No. 14 (2006)

Ordovician

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
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 2006; 29: 183-196
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 2007; 30: 258-270
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 2000; 23: 102-109
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 1997; 20: 158-166
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 2005; 28: 105-117; Episodes 2009; 32: 96-113
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 2004; 27: 265-272
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 2001; 24: 19-28

Cambrian

Stage Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Phanerozoic Eonothem
Paleozoic Erathem
Cambrian System
Furongian Series
Stage 10 ~489.5 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 ~494 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 2012; 35: 462-477
Paibian Stage ~497 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 ~500.5 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 2009; 32: 41-55
Drumian Stage ~504.5 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 2007; 30: 85-95
Stage 5 ~509 candidate sections are Wuliu-Zengjiayan (east Guizhou, China) and Split Mountain (Nevada, USA)     Trilobite, potentially FAD of Oryctocephalus indicus    
Series 2
Stage 4 ~514       Trilobite FAD Olenellus or Redlichia    
Stage 3 ~521       Trilobites - their FAD    
Terreneuvian Series
Stage 2 ~529       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 1994; 17: 95-100

Proterozoic

System Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Precambrian
Proterozoic Eonothem
Neoproterozoic Erathem
Ediacaran System ~635 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 720 Will be placed at a that lies stratigraphically beneath the first appearance of widespread glaciation and is assigned in the interim a 'calibrated age' of circa 720 Ma       Episodes 2019; 39
Tonian System 1000 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Mesoproterozoic Erathem
Stenian System 1200 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Ectasian System 1400 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Calymmian System 1600 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Paleoproterozoic Erathem
Statherian System 1800 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Orosirian System 2050 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Rhyacian System 2300 Defined chronometrically       Ratified 1990 Episodes 1991; 14
Siderian System 2500 Defined chronometrically, but it will be replaced by GSSP       Ratified 1990 Episodes 1991; 14

Archean

System Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Precambrian
Archean Eonothem
Neoarchean Erathem 2800 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 1992; 15
Mesoarchean Erathem 3200 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 1992; 15
Paleoarchean Erathem 3600 Defined chronometrically       Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 1992; 15
Eoarchean Erathem 4031 ± 3

defined chronometrically

along Acasta River, Northwestern Territory, Canada

65.1738°N 115.5538°W Acasta Gneiss Complex Fm., Slave Province, Canadian Shield Ten oldest zircon U-Pb ages Ratified 2023

Episodes, forthcoming (formal GSSA)

Succeeds Episodes 1992; 15 (informal 4000 Ma).

Hadean

System Age (Ma) GSSP Location Latitude, Longitude Boundary Level Correlation Events Status Reference
Precambrian
Hadean Eonothem 4567.30 ± 0.16

defined chronometrically

Data in Amelin et al., 2010 (Allende); Connelly et. al., 2012 (Gujba).

Allende meteorite (1969, Chihuahua, Mexico) Gujba meteorite (1984, Bogga Dingar, Nigeria) Formation of planet Earth and sister Solar planets (protoplanetary disk), by proxy of ages obtained from primitive meteorites U-corrected Pb–Pb age for Calcium-Aluminium Inclusions (CAIs) in class CBa meteorite Ratified 2022 Episodes, forthcoming (formal GSSA)