List of Global Boundary Stratotype Sections and Points

This is a list of Global Boundary Stratotype Sections and Points. Since 1977, Global Boundary Stratotype Sections and Points are internationally agreed upon reference points on stratigraphic sections of rock which define the lower boundaries of stages on the geologic time scale. They are selected by the International Commission on Stratigraphy based on multiple factors, but their accessibility and the degree to which they are representative of the same boundary on sections worldwide are among the most important.
Since GSSPs require well-preserved sections of rock without interruptions in sedimentation, and since most are defined by different stages of animal life, defining them becomes progressively more difficult as one goes farther back in time.

Organization of this list

This list is divided first into the geologic eras of the Phanerozoic and then into the geologic periods of each era. Each period is marked below the era bar on top of its subdivided epochs and stages. Each stage is assigned an age in mya, an acronym for million years ago, which is the age at which it began. Most of these ages are derived from astronomical cycles in sediments, magnetic data, biostratigraphic data, and radiometric dating methods. The GSSP assigned to each stage is that stage's lower boundary and oldest point.
Ages are given in "million year ago". They are obtained with different radiometric dating methods depending on the type of rock and its age. Ages that have a tilde prefix are approximate ages for GSSPs that have not been defined or not been accurately dated.
The Status column has a "golden spike" for every GSSP which has been formally agreed by the ICS. Those without have only candidate sections which have not yet been formally ratified. The clock stands for times that are currently defined only by an age.
The "Defining markers" column lists the evidence in the rock used to define the boundary. Most of the boundaries rely on the fossil record, paleomagnetic data, and/or climate data determined by carbon and oxygen isotopes.

List

[Cenozoic]

[Quaternary]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Holocene	-	-	-	-	-	-	-
Holocene	Meghalayan			Mawmluh Cave, Meghalaya, India	Climatic: 4.2 kiloyear event.
Holocene	Northgrippian			NGRIP1 ice core,Greenland	Climatic: 8.2 kiloyear event.
Holocene	Greenlandian			NGRIP2 ice core,Greenland	Climatic: End of the Younger Dryas stadial.
Pleistocene	-	-	-	-	-	-	-
Pleistocene	Upper/Late			-	Climatic: Marine Isotope Substage 5e	-	-
Pleistocene	Chibanian			Chiba, Japan	Magnetic: Brunhes-Matuyama magnetic reversal.
Pleistocene	Calabrian			Vrica Section,Calabria, Italy	Magnetic: Approximately 15 ka after the end of magnetic polarity chronozone C2n. Biologic: Immediately above extinction Discoaster brouweri. Sedimentologic: Boundary between a sapropelic bed and marine claystones.
Pleistocene	Gelasian			Monte San Nicola Section,Gela, Sicily, Italy	Magnetic: Base of magnetic polarity chronozone C2r. Biologic: Extinction of Discoaster pentaradiatus and Discoaster surculus.

[Neogene]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Pliocene	-	-	-	-	-	-	-
Pliocene	Piacenzian			Punta Piccola Section, Porto Empedocle, Sicily, Italy	Magnetic: Base of magnetic polarity chronozone C2An. Biologic: Extinction of Globorotalia margaritae and Pulleniatina primalis.
Pliocene	Zanclean			Heraclea Minoa sectionHeraclea Minoa, Cattolica Eraclea, Sicily, Italy	Magnetic: Top of magnetic polarity chronozone C3r. Biologic: First appearance of Ceratolithus acutus and near extinction of Triquetrorhabdulus rugosus.
Miocene	-	-	-	-	-	-	-
Miocene	Messinian			Oued Akrech section,Rabat, Morocco	Magnetic: Within magnetic polarity chronozone C3Br.1r. Biologic: First regular occurrence of the Globorotalia miotumida. Biologic: First appearance of Amaurolithus delicatus.
Miocene	Tortonian			Monte dei Corvi Beach section,Ancona, Italy	Magnetic: Within normal-polarity subchron C5r.2n Biologic: Last Common Occurrence of the Discoaster kugleri. Biologic: Last Common Occurrence of the Globigerinoides subquadratus. Climatic: Oxygen isotope event Mi-5.
Miocene	Serravallian			Ras il Pellegrin section,Fomm ir-Riħ Bay, Malta	Magnetic: Within magnetic polarity chronozone C5ABr. Biologic: Below first appearance of Sphenolithus heteromorphus Climatic: Mi3b isotopic event.
Miocene	Langhian			At 17.84 m in the 'Lower La Vedova Beach' section, Ancona, Italy	Magnetic: Near top of magnetic polarity chronozone C5Cn.1n. Biologic: Near first appearance of Praeorbulina glomerosa.
Miocene	Burdigalian			Candidate sections: Astronomically tuned ODP core	Near FAD of Globigerinoides altiaperturus or near top of magnetic polarity chronozone C6An	-
Miocene	Aquitanian			Lemme-Carrosio Section,Carrosio, Italy	Magnetic: Base of magnetic polarity chronozone C6Cn.2n. Biologic: Near first appearance of Paragloborotalia kugleri.

[Paleogene]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Oligocene	-	-	-	-	-	-	-
Oligocene	Chattian			Monte Cagnero, Central Apennines, Italy	Biological: last occurrence of the planktonic foraminifer Chiloguembelina
Oligocene	Rupelian			Massignano quarry section, Massignano, Ancona, Italy	Biologic: Extinction of Hantkenina and Cribrohantkenina.
Eocene	-	-	-	-	-	-	-
Eocene	Priabonian			Alano section,Piave river, Venetian Prealps, Belluno, Italy	Biologic: Last appearance of large acarininids and Morozovelloides crassatus; The Base of common and continuous Cribrocentrum erbae and the Top of Chiasmolithus grandis Magnetic: The Base of Chronozone C17n and Subchron C17n.2n
Eocene	Bartonian			Contessa highway sectionGubbio, Central Apennines, Italy	Biologic: Near Extinction of Reticulofenestra reticulata		-
Eocene	Lutetian			Gorrondatxe sea-cliff section,Western Pyrenees, Basque Country, Spain	Biologic: First appearance of Hantkenina.
Eocene	Ypresian			Dababiya section,Luxor, Egypt	Climatic: Base of negative Carbon Isotope Excursion.
Paleocene	-	-	-	-	-	-	-
Paleocene	Thanetian			Zumaia Section,Basque Country, Spain	Magnetic: Base of magnetic polarity chronozone C26n.
Paleocene	Selandian			Zumaia Section,Basque Country, Spain	Chemical: Onset of sea-level drop and carbon isotope shift. Magnetic: 30 precession cycles after the top of magnetic polarity Chron 27n
Paleocene	Danian			El Kef Section,El Kef, Tunisia	Iridium enriched layer associated with a major meteorite impact and subsequent extinction event.

[Mesozoic]

[Cretaceous]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Upper	-	-	-	-	-	-	-
Upper	Maastrichtian			Grande Carrière quarry, Landes, France	Biologic: 12 biostratigraphic criteria Biologic: First appearance of Pachydiscus neubergicus is just above the boundary.
Upper	Campanian			Bottaccione, Gubbio, Italy	Magnetic: Base of Chron C33r.
Upper	Santonian			Olazagutia, Spain	Biologic: First appearance of Cladoceramus undulatoplicatus.
Upper	Coniacian			Salzgitter-Salder quarry, Germany	Biologic: First appearance of Cremnoceramus rotundatus.
Upper	Turonian			Rock Canyon,Colorado, United States	Biologic: First appearance of Watinoceras devonense.
Upper	Cenomanian			Mont Risoux,Hautes-Alpes, France	Biologic: First appearance of Rotalipora globotruncanoides
Lower	-	-	-	-	-	-	-
Lower	Albian			Col de Pré-Guittard section, Arnayon, Drôme, France	Biologic: first appearance of the planktonic foraminiferan Microhedbergella renilaevis.
Lower	Aptian			Candidate section: Gorgo a Cerbara, Piobbico, Central Apennines, Italy	Magnetic: Base of magnetic polarity chronozone M0r. Biologic: Near first appearance of Paradeshayesites oglanlensis.	-	-
Lower	Barremian			Río Argos, Caravaca de la Cruz, Murcia Province, Spain	Biologic: First appearance of Ammonite Taveraidiscus hugii.	-
Lower	Hauterivian			La Charce, Drôme, France	Biologic: First appearance of the Ammonite genus Acanthodiscus.
Lower	Valanginian			Montbrun-les-Bains, Drôme, France	Biologic: First appearance of Thurmanniceras pertransiens.
Lower	Berriasian			Candidate section: Vaca Muerta, Neuquén Basin, Argentina	Candidates: Magnetic—base of Chron M18r Base of Calpionellid zone B

[Jurassic]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Upper	-	-	-	-	-	-	-
Upper	Tithonian			Candidate sections: Mt. Crussol, France Canjuers, France Fornazzo, Sicily	Magnetic: Base of magnetic polarity chronozone M22An. Biologic: Near first appearance of Hybonoticeras hybonotum. Biologic: First appearance of genus Gravesia.	-	-
Upper	Kimmeridgian			Flodigarry, Isle of Skye, Scotland, U.K.	Biologic: First appearance of Pictonia baylei.
Upper	Oxfordian			Candidate sections: Redcliff Point, Dorset, England, U.K. Savouron, Provence, France	Biologic: Horizon of Cardioceras redcliffense.	-	-
Middle	-	-	-	-	-	-	-
Middle	Callovian			Candidate sections: Pfeffingen, Swabian Alb, Germany Russia	Biologic: First appearance of genus Kepplerites.	-	-
Middle	Bathonian			Ravin du Bès, Bas-Auran, Alpes de Haute, France	Biologic: First appearance of Gonolkites convergen.
Middle	Bajocian			Cabo Mondego, Portugal	Biologic: First appearance of Hyperlioceras mundum, Hyperlioceras furcatum, Braunsina aspera, and Braunsina elegantula Biologic: First appearance of genus Hyperlioceras.
Middle	Aalenian			Fuentelsaz, Spain	Biologic: First appearance of Leioceras opalinum and Leioceras lineatum Biologic: First appearance of genus Leioceras.
Lower	-	-	-	-	-	-	-
Lower	Toarcian			Peniche, Portugal	Biologic: First appearance of D. (E.) simplex.
Lower	Pliensbachian			Robin Hood's Bay, Yorkshire, England, U.K.	Biologic: First appearance of Bifericeras donovani and genera Apoderoceras.
Lower	Sinemurian			East Quantoxhead, West Somerset, England, UK	Biologic: First appearance of the Vermiceras quantoxense, Vermiceras palmeri .
Lower	Hettangian			Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria	Biologic: Near first appearance of smooth Psiloceras spela group.

[Triassic]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Upper	-	-	-	-	-	-	-
Upper	Rhaetian	~		Candidate sections: Steinbergkogel, Austria Pignola-Abriola, Italy Turkey British Columbia	Biologic: First appearance of Misikella posthernsteini. Biologic: Near first appearance of genus Cochloceras. Biologic: Near first appearance of Epigondolella mosheri. Biologic: Near first appearance of Proparvicingula moniliformis.	-	-
Upper	Norian	~		Candidate sections: Black Bear Ridge, British Columbia Pizzo Mondello, Sicily	Base of Stikinoceras kerri ammonoid zone and near FAD of Metapolygnathus echinatus within the M. communisti conodont zones.	-	-
Upper	Carnian	~		Prati di Stuores, Dolomites, Italy	Biologic: First appearance of Daxatina canadensis. Biologic: Near first appearance of Metapolygnathus polygnathiformis. Magnetic: Above magnetic zone S2n.
Middle	-	-	-	-	-	-	-
Middle	Ladinian			Bagolino, Lombardian pre-Alps, Italy	Biologic: First appearance of Eoprotrachyceras curionii. Biologic: First appearance of Budurovignathus praehungaricus.
Middle	Anisian			Candidate sections: Desli Caira, Northern Dobruja, Romania Guandao, Guizhou, China	Biologic: First appearance of Chiosella timorensis. Magnetic: Base of magnetic zone MT1n.
Lower	-	-	-	-	-	-	-
Lower	Olenekian			Candidate sections: Mud village, Spiti valley, India Chaohu, China	Biologic: First appearance of Neospathodus waageni. Biologic: Near first appearance of genera Flemingites and Euflemingites.
Lower	Induan	251.902		Meishan, Zhejiang, China	Biologic: First appearance of Hindeodus parvus.

[Paleozoic]

[Permian]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Lopingian	-	-	-	-	-	-	-
Lopingian	Changhsingian			Zhejiang, China	Biologic: Near first appearance of Clarkina wangi.
Lopingian	Wuchiapingian			Penglaitan Section,Laibin, Guangxi, China	Biologic: First appearance of Clarkina postbitteri postbitteri.
Guadalupian	-	-	-	-	-	-	-
Guadalupian	Capitanian			Nipple Hill, Guadalupe Mountains, Texas, U.S.A.	Biologic: First appearance of Jinogondolella postserrata.
Guadalupian	Wordian			Guadalupe Pass, Guadalupe Mountains, Texas, U.S.A.	Biologic: First appearance of Jinogondolella aserrata.
Guadalupian	Roadian			Stratotype Canyon, Guadalupe Mountains, Texas, U.S.A.	Biologic: First appearance of Jinogondolella nanginkensis.
Cisuralian	-	-	-	-	-	-	-
Cisuralian	Kungurian			Candidate section: Mechetlino, Southern Ural Mountains, Russia	Biologic: Near first appearance of Neostreptognathodus pnevi.	-
Cisuralian	Artinskian			Dalny Tulkas section, Southern Ural Mountains, Russia	Biologic: First appearance of Sweetognathus whitei.
Cisuralian	Sakmarian			Usolka section, Southern Urals, Russia	Biologic: First appearance of Mesogondolella monstra.
Cisuralian	Asselian			Aidaralash, Ural Mountains, Kazakhstan	Biologic: First appearance of Streptognathodus isolatus within the morphotype Streptognathodus wabaunsensis chronocline.

[Carboniferous]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Pennsylvanian	-	-	-	-	-	-	-
Pennsylvanian	Gzhelian			Candidate sections: Ural mountains Nashui, Luodian County, Guizhou, China	Biologic: First appearance Idiognathodus simulator and close to first appearance of Shumardites	-
Pennsylvanian	Kasimovian			Candidate sections: Ural mountains United States Nashui, Luodian County, Guizhou, China	Biologic: First appearance of Protriticites or 1 million years older Montiparus montiparus	-
Pennsylvanian	Moscovian			Candidate sections: Ural mountains Nashui, Luodian County, Guizhou, China	Biologic: First appearance of Idiognathoides postsulcatus or Declinognathodus donetzianus	-
Pennsylvanian	Bashkirian			Arrow Canyon, Nevada, United States	Biologic: First appearance of Declinognathodus nodiliferus.
Mississippian	-	-	-	-	-	-	-
Mississippian	Serpukhovian			Candidate sections: Verkhnyaya Kardailovka, Ural mountains Nashui, Luodian County, Guizhou, China	Biologic: First appearance of Lochriea ziegleri	-
Mississippian	Visean			Pengchong Section,Guangxi, China	Biologic: First appearance of Eoparastaffella simplex
Mississippian	Tournaisian			La Serre, Montagne Noire, France	Biologic: First appearance of Siphonodella sulcata. In 2006 it was discovered that this GSSP has biostratigraphic problems.

[Devonian]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Upper	-	-	-	-	-	-	-
Upper	Famennian			Coumiac quarry, Montagne Noire, France	Biologic: Abundant occurrence of Palmatolepis triangularis. Biologic: Upper Kellwasser Extinction of all Ancyrodella and Ozarkodina and most Palmatolepis, Polygnathus, and Ancyrognathus. Biologic: Coincides with the first appearance of Phoenixites frechi.
Upper	Frasnian			Col du Puech de la Suque, Montagne Noire, France	Biologic: First appearance of Ancyrodella rotundiloba.
Middle	-	-	-	-	-	-	-
Middle	Givetian			Jebel Mech Irdane, Tafilalt, Morocco	Biologic: First appearance of Polygnathus hemiansatus. Biologic: Just below first appearance of Maenioceras.
Middle	Eifelian			Wetteldorf Richtschnitt section,Wetteldorf, Eifel, Germany	Biologic: First appearance of Polygnathus costatus partitus.
Lower	-	-	-	-	-	-	-
Lower	Emsian			Zinzil'ban Gorge, Uzbekistan	Biologic: First appearance of Polygnathus kitabicus.
Lower	Pragian			Velká Chuchle quarryVelká Chuchle, Prague, Czech Republic	Biologic: First appearance of Eognathodus sulcatus.
Lower	Lochkovian			Klonk, Prague, Czech Republic	Biologic: First appearance of Monograptus uniformis.

[Ordovician]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Upper	-	-	-	-	-	-	-
Upper	Hirnantian			Wangjiawan section Wangjiawan, Yichang, China	Biologic: First appearance of Normalograptus extraordinarius. Climatic: Base of major positive carbon isotope excursion. Climatic: Beginning of sea-level fall associated with onset of a major glaciation.
Upper	Katian			Black Knob Ridge section,Oklahoma, United States	Biologic: First appearance of Diplacanthograptus caudatus. Climatic: Just below base of Guttenberg carbon isotope excursion.
Upper	Sandbian			Fågelsång sectionSularp Brook, Skåne, Sweden	Biologic: First appearance of Nemagraptus gracilis. 1.4 m below a phosphorite marker bed.
Middle	-	-	-	-	-	-	-
Middle	Darriwilian			Huangnitang SectionHuangnitang Village, Changshan, Zhejiang, China	Biologic: First appearance of Undulograptus austrodentatus.
Middle	Dapingian			Huanghuachang sectionHuanghuachang, Yichang, China	Biologic: Lowest appearance of Baltoniodus triangularis.
Lower	-	-	-	-	-	-	-
Lower	Floian			Diabasbrottet quarry,Västergötland, Sweden	Biologic: Lowest appearance of Tetragraptus approximatus.
Lower	Tremadocian			Greenpoint sectionGreen Point, Newfoundland, Canada	Biologic: First appearance of Iapetognathus fluctivagus. Biologic: Planktonic graptolites occur 4.8 m above boundary. Climatic: Coincides with a peak in carbon isotopes.

[Cambrian]

Epoch	Stage	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Furongian	-	-	-	-	-	-	-
Furongian	Stage 10			Candidate sections: Duibian, Zhejiang, China Lawson Cove, Utah, United States	Candidates: Biologic: First appearance of Lotagnostus americanus. Biologic: First appearance of Cordylodus andresi. Biologic: First appearance of Eoconodontus notchpeakensis.	-
Furongian	Jiangshanian	~		Duibian B SectionDuibian, Zhejiang, China	Biologic: First appearance of Agnostotes orientalis.
Furongian	Paibian	~		Paibi sectionPaibi, Hunan, China	Biologic: First appearance of the agnostoid Glyptagnostus reticulatus. Climatic: Coincides with base of the Steptoean positive carbon isotope excursion.
Miaolingian	-	-	-	-	-	-	-
Miaolingian	Guzhangian	~		Luoyixi sectionLuoyixi, Guzhang, Hunan, China	Biologic: First appearance of Lejopyge laevigata.
Miaolingian	Drumian	~		Drumian sectionWheeler Shale, Utah, U.S.A.	Biologic: First appearance of Ptychagnostus atavus.
Miaolingian	Wuliuan	~		Wuliu-Zengjiayan, Guizhou, China	Biologic: First appearance of Oryctocephalus indicus.
Series 2	-	-	-	-	-	-	-
Series 2	Stage 4	~		-	Biologic: First appearance Arthricocephalus chauveaui. Biologic: First appearance Olenellus or Redlichia.	-
Series 2	Stage 3	~		-	Biologic: First appearance of trilobites	-
Terreneuvian	-	-	-	-	-	-	-
Terreneuvian	Stage 2	~		-	Biologic: First appearance of small shelly fauna or archaeocyathids	-	-
Terreneuvian	Fortunian			Fortune head section,Newfoundland, Canada	Biologic: First appearance of Treptichnus pedum.

[Precambrian]

[Proterozoic]

Era	Period	Age	Status	GSSP location	Defining markers	Geographic Coordinates	References
Neoproterozoic	-	-	-	-	-	-	-
Neoproterozoic	Ediacaran	~		Enorama Creek section, Flinders Ranges, South Australia	Geologic: Worldwide distinct cap carbonates. Isotopic: Beginning of a distinctive pattern of secular changes in carbon isotopes.
Neoproterozoic	Cryogenian	~		Defined chronometrically with an interim calibrated age of ca. 720 Ma. GSSP is in progress.	Geologic: the GSSP has been recommended to be placed at a stratigraphic level beneath the first appearance of widespread glaciation associated with the Sturtian glacial epoch.	-
Neoproterozoic	Tonian			Defined chronometrically	-	-
Mesoproterozoic	-	-	-	-	-	-	-
Mesoproterozoic	Stenian			Defined chronometrically	-	-
Mesoproterozoic	Ectasian			Defined chronometrically	-	-
Mesoproterozoic	Calymmian			Defined chronometrically	-	-
Paleoproterozoic	-	-	-	-	-	-	-
Paleoproterozoic	Statherian			Defined chronometrically	-	-
Paleoproterozoic	Orosirian			Defined chronometrically	-	-
Paleoproterozoic	Rhyacian			Defined chronometrically	-	-
Paleoproterozoic	Siderian			Defined chronometrically	-	-

[Archean] and [Hadean]

Eon	Era	Age	Status	GSSP/GSSA location	Defining markers	Geographic Coordinates	References
Archean	-	-	-	-	-	-	-
Archean	Neoarchean			-	Defined chronometrically	-	-
Archean	Mesoarchean			-	Defined chronometrically	-	-
Archean	Paleoarchean			-	Defined chronometrically	-	-
Archean	Eoarchean	4031		Along the Acasta River, Northwest Territories, Canada	Defined chronometrically Ten oldest U-Pb zircon ages
Hadean	-	4567.3		-	Defined chronometrically Formation of the Solar System	-