# 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 (abbreviated GSSPs) 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 (the Cenozoic, the Mesozoic, and the Paleozoic) 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" (mya). 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. (Ideally, these are applicable in rock sections worldwide.) Most of the boundaries rely on the fossil record (biologic), paleomagnetic data (magnetic), and/or climate data determined by carbon and oxygen isotopes.

## List
### Cenozoic
#### Quaternary

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Holocene |
| Holocene | Meghalayan | 0.0042 | Mawmluh Cave, Meghalaya, India | Climatic: 4.2 kiloyear event. | 25°15′44″N 91°42′54″E﻿ / ﻿25.2622°N 91.7150°E﻿ / 25.2622; 91.7150 | |
| Holocene | Northgrippian | 0.0082 | NGRIP1 ice core, Greenland | Climatic: 8.2 kiloyear event. | 75°06′00″N 42°19′12″W﻿ / ﻿75.1000°N 42.3200°W﻿ / 75.1000; -42.3200 | |
| Holocene | Greenlandian | 0.0117 | NGRIP2 ice core, Greenland | Climatic: End of the Younger Dryas stadial. | 75°06′00″N 42°19′12″W﻿ / ﻿75.1000°N 42.3200°W﻿ / 75.1000; -42.3200 | |
| Pleistocene |
| Pleistocene | Upper/Late | 0.129 | - | Climatic: Marine Isotope Substage 5e | - | - |
| Pleistocene | Chibanian | 0.774 | Chiba, Japan | Magnetic: Brunhes-Matuyama magnetic reversal. | 35°17′39″N 140°08′47″E﻿ / ﻿35.2943°N 140.1465°E﻿ / 35.2943; 140.1465 | |
| Pleistocene | Calabrian | 1.8 | Vrica Section, Calabria, Italy | Magnetic: Approximately 15 ka after the end of magnetic polarity chronozone C2n (Olduvai). Biologic: Immediately above extinction Discoaster brouweri (Haptophyte). Sedimentologic: Boundary between a sapropelic bed and marine claystones. | 39°02′19″N 17°08′05″E﻿ / ﻿39.0385°N 17.1348°E﻿ / 39.0385; 17.1348 | |
| Pleistocene | Gelasian | 2.58 | Monte San Nicola Section, Gela, Sicily, Italy | Magnetic: Base of magnetic polarity chronozone C2r (Matuyama). Biologic: Extinction of Discoaster pentaradiatus and Discoaster surculus (Haptophyte). | 37°08′47″N 14°12′16″E﻿ / ﻿37.146468°N 14.204562°E﻿ / 37.146468; 14.204562 | |

#### Neogene

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Pliocene |
| Pliocene | Piacenzian | 3.6 | Punta Piccola Section, Porto Empedocle, Sicily, Italy | Magnetic: Base of magnetic polarity chronozone C2An (Gauss). Biologic: Extinction of Globorotalia margaritae and Pulleniatina primalis (Planktonic foraminifera). | 37°17′22″N 13°29′29″E﻿ / ﻿37.289386°N 13.491443°E﻿ / 37.289386; 13.491443 |
| Pliocene | Zanclean | 5.333 | Heraclea Minoa section Heraclea Minoa, Cattolica Eraclea, Sicily, Italy | Magnetic: Top of magnetic polarity chronozone C3r. Biologic: First appearance of Ceratolithus acutus and near extinction of Triquetrorhabdulus rugosus (Haptophyte). | 37°23′33″N 13°16′52″E﻿ / ﻿37.392435°N 13.281052°E﻿ / 37.392435; 13.281052 |
| Miocene |
| Miocene | Messinian | 7.246 | Oued Akrech section, Rabat, Morocco | Magnetic: Within magnetic polarity chronozone C3Br.1r. Biologic: First regular occurrence of the Globorotalia miotumida (Planktonic foraminifera). Biologic: First appearance of Amaurolithus delicatus (Haptophyte). | 33°55′30″N 6°48′33″W﻿ / ﻿33.925050°N 6.809047°W﻿ / 33.925050; -6.809047 |
| Miocene | Tortonian | 11.63 | Monte dei Corvi Beach section, Ancona, Italy | Magnetic: Within normal-polarity subchron C5r.2n Biologic: Last Common Occurrence of the Discoaster kugleri (Haptophyte). Biologic: Last Common Occurrence of the Globigerinoides subquadratus (Planktonic foraminifera). Climatic: Oxygen isotope event Mi-5. | 43°35′14″N 13°33′58″E﻿ / ﻿43.587242°N 13.566148°E﻿ / 43.587242; 13.566148 |
| Miocene | Serravallian | 13.82 | Ras il Pellegrin section, Fomm ir-Riħ Bay, Malta | Magnetic: Within magnetic polarity chronozone C5ABr. Biologic: Below first appearance of Sphenolithus heteromorphus (Haptophyte) Climatic: Mi3b isotopic event (Global cooling episode). | 35°54′50″N 14°20′10″E﻿ / ﻿35.9139°N 14.3361°E﻿ / 35.9139; 14.3361 |
| Miocene | Langhian | 15.98 | 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 (Planktonic foraminifera). | 43°35′31″N 13°33′44″E﻿ / ﻿43.5919°N 13.5623°E﻿ / 43.5919; 13.5623 |
| Miocene | Burdigalian | 20.45 | Candidate sections: Astronomically tuned ODP core (e.g. Ceara Rise, Leg 154) | Near FAD of Globigerinoides altiaperturus (planktonic foraminifer) or near top of magnetic polarity chronozone C6An | - |
| Miocene | Aquitanian | 23.04 | Lemme-Carrosio Section, Carrosio, Italy | Magnetic: Base of magnetic polarity chronozone C6Cn.2n. Biologic: Near first appearance of Paragloborotalia kugleri (Planktonic foraminifera). | 44°39′36″N 8°50′21″E﻿ / ﻿44.6601°N 8.83928°E﻿ / 44.6601; 8.83928 |

#### Paleogene

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Oligocene |
| Oligocene | Chattian | 27.3 | Monte Cagnero, Central Apennines, Italy | Biological: last occurrence of the planktonic foraminifer Chiloguembelina (Base of Foram Zone P21b) | 43°38′48″N 12°28′04″E﻿ / ﻿43.646748°N 12.467771°E﻿ / 43.646748; 12.467771 | |
| Oligocene | Rupelian | 33.9 | Massignano quarry section, Massignano, Ancona, Italy | Biologic: Extinction of Hantkenina and Cribrohantkenina (Planktonic foraminifera). | 43°32′10″N 13°35′33″E﻿ / ﻿43.536038°N 13.592499°E﻿ / 43.536038; 13.592499 | |
| Eocene |
| Eocene | Priabonian | 37.71 | 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 | 45°54′51″N 11°55′05″E﻿ / ﻿45.9141°N 11.9180°E﻿ / 45.9141; 11.9180 | |
| Eocene | Bartonian | 41.03 | Contessa highway section Gubbio, Central Apennines, Italy | Biologic: Near Extinction of Reticulofenestra reticulata (Haptophyte) | 43°22′47″N 12°33′44″E﻿ / ﻿43.37972°N 12.56219°E﻿ / 43.37972; 12.56219 | - |
| Eocene | Lutetian | 48.07 | Gorrondatxe sea-cliff section, Western Pyrenees, Basque Country, Spain | Biologic: First appearance of Hantkenina (Planktonic foraminifera). | 43°22′47″N 3°00′51″W﻿ / ﻿43.3796°N 3.0143°W﻿ / 43.3796; -3.0143 | |
| Eocene | Ypresian | 56 | Dababiya section, Luxor, Egypt | Climatic: Base of negative Carbon Isotope Excursion (CIE). | 25°30′00″N 32°31′52″E﻿ / ﻿25.5000°N 32.5311°E﻿ / 25.5000; 32.5311 | |
| Paleocene |
| Paleocene | Thanetian | 59.24 | Zumaia Section, Basque Country, Spain | Magnetic: Base of magnetic polarity chronozone C26n. | 43°17′59″N 2°15′39″W﻿ / ﻿43.2996°N 2.2609°W﻿ / 43.2996; -2.2609 | |
| Paleocene | Selandian | 61.66 | 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 | 43°17′57″N 2°15′40″W﻿ / ﻿43.2992°N 2.2610°W﻿ / 43.2992; -2.2610 | |
| Paleocene | Danian | 66 | El Kef Section, El Kef, Tunisia | Iridium enriched layer associated with a major meteorite impact and subsequent extinction event. | 36°09′13″N 8°38′55″E﻿ / ﻿36.1537°N 8.6486°E﻿ / 36.1537; 8.6486 | |

### Mesozoic
#### Cretaceous

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Upper |
| Upper | Maastrichtian | 72.2 | Grande Carrière quarry, Landes, France | Biologic: 12 biostratigraphic criteria Biologic: First appearance of Pachydiscus neubergicus (Ammonite) is just above the boundary. | 43°40′46″N 1°06′48″W﻿ / ﻿43.6795°N 1.1133°W﻿ / 43.6795; -1.1133 | |
| Upper | Campanian | 83.6 | Bottaccione, Gubbio, Italy | Magnetic: Base of Chron C33r. | 43°21′46″N 12°34′58″E﻿ / ﻿43.3627°N 12.5828°E﻿ / 43.3627; 12.5828 | |
| Upper | Santonian | 85.7 | Olazagutia, Spain | Biologic: First appearance of Cladoceramus undulatoplicatus (Inoceramid bivalve). | 42°52′00″N 2°11′48″W﻿ / ﻿42.8668°N 2.1968°W﻿ / 42.8668; -2.1968 | |
| Upper | Coniacian | 89.8 | Salzgitter-Salder quarry, Germany | Biologic: First appearance of Cremnoceramus rotundatus (Inoceramid bivalve). | 52°07′27″N 10°19′46″E﻿ / ﻿52.1243°N 10.3295°E﻿ / 52.1243; 10.3295 | |
| Upper | Turonian | 93.9 | Rock Canyon, Colorado, United States | Biologic: First appearance of Watinoceras devonense (Ammonite). | 38°16′56″N 104°43′39″W﻿ / ﻿38.2822°N 104.7275°W﻿ / 38.2822; -104.7275 | |
| Upper | Cenomanian | 100.5 | Mont Risoux, Hautes-Alpes, France | Biologic: First appearance of Rotalipora globotruncanoides (Planktonic foraminifera) | 44°23′28″N 5°30′39″E﻿ / ﻿44.391120°N 5.510970°E﻿ / 44.391120; 5.510970 | |
| Lower |
| Lower | Albian | 113.2 | Col de Pré-Guittard section, Arnayon, Drôme, France | Biologic: first appearance of the planktonic foraminiferan Microhedbergella renilaevis. | 44°30′28″N 5°17′50″E﻿ / ﻿44.507861°N 5.297250°E﻿ / 44.507861; 5.297250 | [26] [27] |
| Lower | Aptian | 121.4 | Candidate section: Gorgo a Cerbara, Piobbico, Central Apennines, Italy | Magnetic: Base of magnetic polarity chronozone M0r. Biologic: Near first appearance of Paradeshayesites oglanlensis (Ammonite). | - | - |
| Lower | Barremian | 125.77 | Río Argos, Caravaca de la Cruz, Murcia Province, Spain | Biologic: First appearance of Ammonite Taveraidiscus hugii. | - | |
| Lower | Hauterivian | 132.6 | La Charce, Drôme, France | Biologic: First appearance of the Ammonite genus Acanthodiscus. | 44°28′10″N 5°26′37″E﻿ / ﻿44.4694°N 5.4437°E﻿ / 44.4694; 5.4437 | |
| Lower | Valanginian | 137.05 | Candidates sections: Montbrun-les-Bains, Drôme, France Cañada Luenga, Betic Cordillera, Spain | Biologic: First appearance of Calpionellites darderi (Calpionellid). Biologic: First appearance of Thurmanniceras pertransiens (Ammonite). | - | - |
| Lower | Berriasian | 143.1 | Candidate section: Vaca Muerta, Neuquén Basin, Argentina | Candidates: Magnetic—base of Chron M18r Base of Calpionellid zone B | | |

#### Jurassic

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Upper |
| Upper | Tithonian | 149.2 | Candidate sections: Mt. Crussol, France Canjuers, France Fornazzo, Sicily | Magnetic: Base of magnetic polarity chronozone M22An. Biologic: Near first appearance of Hybonoticeras hybonotum (Ammonite). Biologic: First appearance of genus Gravesia (Ammonite). | - | - |
| Upper | Kimmeridgian | 154.8 | Flodigarry, Isle of Skye, Scotland, U.K. | Biologic: First appearance of Pictonia baylei (Ammonite). | 57°39′40″N 6°14′44″W﻿ / ﻿57.6610°N 6.2455°W﻿ / 57.6610; -6.2455 | |
| Upper | Oxfordian | 161.5 | Candidate sections: Redcliff Point, Dorset, England, U.K. Savouron, Provence, France | Biologic: Horizon of Cardioceras redcliffense (Ammonite). | - | - |
| Middle |
| Middle | Callovian | 165.3 | Candidate sections: Pfeffingen, Swabian Alb, Germany Russia | Biologic: First appearance of genus Kepplerites (Ammonite). | - | - |
| Middle | Bathonian | 168.2 | Ravin du Bès, Bas-Auran, Alpes de Haute, France | Biologic: First appearance of Gonolkites convergen (Ammonite). | 43°57′38″N 6°18′55″E﻿ / ﻿43.9606°N 6.3153°E﻿ / 43.9606; 6.3153 | |
| Middle | Bajocian | 170.9 | Cabo Mondego, Portugal | Biologic: First appearance of Hyperlioceras mundum, Hyperlioceras furcatum, Braunsina aspera, and Braunsina elegantula(Ammonite) Biologic: First appearance of genus Hyperlioceras (Ammonite). | 40°11′57″N 8°54′15″W﻿ / ﻿40.1992°N 8.9042°W﻿ / 40.1992; -8.9042 | |
| Middle | Aalenian | 174.7 | Fuentelsaz, Spain | Biologic: First appearance of Leioceras opalinum and Leioceras lineatum Biologic: First appearance of genus Leioceras (Ammonite). | 41°4′44.9″N 1°49′49.2″W﻿ / ﻿41.079139°N 1.830333°W﻿ / 41.079139; -1.830333 | |
| Lower |
| Lower | Toarcian | 184.2 | Peniche, Portugal | Biologic: First appearance of D. (E.) simplex (Ammonite). | 39°22′15″N 9°23′07″W﻿ / ﻿39.3708°N 9.3853°W﻿ / 39.3708; -9.3853 | |
| Lower | Pliensbachian | 192.9 | Robin Hood's Bay, Yorkshire, England, U.K. | Biologic: First appearance of Bifericeras donovani and genera Apoderoceras (Ammonite). | 54°24′25″N 0°29′51″W﻿ / ﻿54.4069°N 0.4975°W﻿ / 54.4069; -0.4975 | |
| Lower | Sinemurian | 199.5 | East Quantoxhead, West Somerset, England, UK | Biologic: First appearance of the Vermiceras quantoxense, Vermiceras palmeri (Ammonite). | 51°11′27″N 3°14′11″W﻿ / ﻿51.1909°N 3.2364°W﻿ / 51.1909; -3.2364 | |
| Lower | Hettangian | 201.4 | Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria | Biologic: Near first appearance of smooth Psiloceras spela group (Ammonite). | 47°29′02″N 11°31′50″E﻿ / ﻿47.4839°N 11.5306°E﻿ / 47.4839; 11.5306 | |

#### Triassic

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Upper |
| Upper | Rhaetian | ~205.7 | Candidate sections: Steinbergkogel, Austria Pignola-Abriola, Italy Turkey British Columbia | Biologic: First appearance of Misikella posthernsteini (Conodont). Biologic: Near first appearance of genus Cochloceras (Ammonite). Biologic: Near first appearance of Epigondolella mosheri (Conodont). Biologic: Near first appearance of Proparvicingula moniliformis (radiolarian). | - | - |
| Upper | Norian | ~227.3 | 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 | ~237 | Prati di Stuores, Dolomites, Italy | Biologic: First appearance of Daxatina canadensis (Ammonite). Biologic: Near first appearance of Metapolygnathus polygnathiformis (Conodont). Magnetic: Above magnetic zone S2n. | 46°31′37″N 11°55′49″E﻿ / ﻿46.5269°N 11.9303°E﻿ / 46.5269; 11.9303 | |
| Middle |
| Middle | Ladinian | ~241.464 | Bagolino, Lombardian pre-Alps, Italy | Biologic: First appearance of Eoprotrachyceras curionii (Ammonite). Biologic: First appearance of Budurovignathus praehungaricus (Conodont). | 45°49′06″N 10°28′13″E﻿ / ﻿45.818380°N 10.470270°E﻿ / 45.818380; 10.470270 | |
| Middle | Anisian | 246.7 | Candidate sections: Desli Caira, Northern Dobruja, Romania Guandao, Guizhou, China | Biologic: First appearance of Chiosella timorensis (Conodont). Magnetic: Base of magnetic zone MT1n. | 45°04′27″N 28°48′08″E﻿ / ﻿45.0742°N 28.8022°E﻿ / 45.0742; 28.8022 | |
| Lower |
| Lower | Olenekian | 249.9 | Candidate sections: Mud (Muth) village, Spiti valley, India Chaohu, China | Biologic: First appearance of Neospathodus waageni (Conodont). Biologic: Near first appearance of genera Flemingites and Euflemingites (Ammonite). | 31°57′55″N 78°01′29″E﻿ / ﻿31.9654°N 78.0246°E﻿ / 31.9654; 78.0246 | |
| Lower | Induan | 251.9 | Meishan, Zhejiang, China | Biologic: First appearance of Hindeodus parvus (Conodont). | 31°04′47″N 119°42′21″E﻿ / ﻿31.0798°N 119.7058°E﻿ / 31.0798; 119.7058 | |

### Paleozoic
#### Permian

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Lopingian |
| Lopingian | Changhsingian | 254.14 | Zhejiang, China | Biologic: Near first appearance of Clarkina wangi (Conodont). | 31°04′55″N 119°42′23″E﻿ / ﻿31.0819°N 119.7064°E﻿ / 31.0819; 119.7064 |
| Lopingian | Wuchiapingian | 259.51 | Penglaitan Section, Laibin, Guangxi, China | Biologic: First appearance of Clarkina postbitteri postbitteri (Conodont). | 23°41′43″N 109°19′16″E﻿ / ﻿23.6953°N 109.3211°E﻿ / 23.6953; 109.3211 |
| Guadalupian |
| Guadalupian | Capitanian | 264.28 | Nipple Hill, Guadalupe Mountains, Texas, U.S.A. | Biologic: First appearance of Jinogondolella postserrata (Conodont). | 31°54′33″N 104°47′21″W﻿ / ﻿31.9091°N 104.7892°W﻿ / 31.9091; -104.7892 |
| Guadalupian | Wordian | 266.9 | Guadalupe Pass, Guadalupe Mountains, Texas, U.S.A. | Biologic: First appearance of Jinogondolella aserrata (Conodont). | 31°51′57″N 104°49′58″W﻿ / ﻿31.8658°N 104.8328°W﻿ / 31.8658; -104.8328 |
| Guadalupian | Roadian | 274.4 | Stratotype Canyon, Guadalupe Mountains, Texas, U.S.A. | Biologic: First appearance of Jinogondolella nanginkensis (Conodont). | 31°52′36″N 104°52′36″W﻿ / ﻿31.8767°N 104.8768°W﻿ / 31.8767; -104.8768 |
| Cisuralian |
| Cisuralian | Kungurian | 283.3 | Candidate section: Mechetlino, Southern Ural Mountains, Russia | Biologic: Near first appearance of Neostreptognathodus pnevi (Conodont). | - |
| Cisuralian | Artinskian | 290.1 | Dalny Tulkas section, Southern Ural Mountains, Russia | Biologic: First appearance of Sweetognathus whitei (Conodont). | 53°53′18″N 56°30′58″E﻿ / ﻿53.88847°N 56.51615°E﻿ / 53.88847; 56.51615 |
| Cisuralian | Sakmarian | 293.52 | Usolka section, Southern Urals, Russia | Biologic: First appearance of Mesogondolella monstra (Conodont). | 53°55′29″N 56°43′43″E﻿ / ﻿53.9247°N 56.7287°E﻿ / 53.9247; 56.7287 |
| Cisuralian | Asselian | 298.9 | Aidaralash, Ural Mountains, Kazakhstan | Biologic: First appearance of Streptognathodus isolatus within the morphotype Streptognathodus wabaunsensis chronocline (Conodont). | 50°14′45″N 57°53′29″E﻿ / ﻿50.2458°N 57.8914°E﻿ / 50.2458; 57.8914 |

#### Carboniferous

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Pennsylvanian |
| Pennsylvanian | Gzhelian | 303.7 | Candidate sections: Ural mountains Nashui, Luodian County, Guizhou, China | Biologic: First appearance Idiognathodus simulator and close to first appearance of Shumardites | - |
| Pennsylvanian | Kasimovian | 307 | 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 | 315.2 | Candidate sections: Ural mountains Nashui, Luodian County, Guizhou, China | Biologic: First appearance of Idiognathoides postsulcatus or Declinognathodus donetzianus | - |
| Pennsylvanian | Bashkirian | 323.4 | Arrow Canyon, Nevada, United States | Biologic: First appearance of Declinognathodus nodiliferus (Conodont). | 36°44′00″N 114°46′40″W﻿ / ﻿36.7333°N 114.7778°W﻿ / 36.7333; -114.7778 |
| Mississippian |
| Mississippian | Serpukhovian | 330.3 | Candidate sections: Verkhnyaya Kardailovka, Ural mountains Nashui, Luodian County, Guizhou, China | Biologic: First appearance of Lochriea ziegleri | - |
| Mississippian | Visean | 346.7 | Pengchong Section, Guangxi, China | Biologic: First appearance of Eoparastaffella simplex | 24°26′00″N 109°27′00″E﻿ / ﻿24.4333°N 109.4500°E﻿ / 24.4333; 109.4500 |
| Mississippian | Tournaisian | 358.86 | La Serre, Montagne Noire, France | Biologic: First appearance of Siphonodella sulcata (Conodont). In 2006 it was discovered that this GSSP has biostratigraphic problems. | 43°33′20″N 3°21′31″E﻿ / ﻿43.55554°N 3.35868°E﻿ / 43.55554; 3.35868 |

#### Devonian

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Upper |
| Upper | Famennian | 372.15 | Coumiac quarry,Coumiac [fr] Montagne Noire, France | Biologic: Abundant occurrence of Palmatolepis triangularis (Conodont). Biologic: Upper Kellwasser Extinction of all Ancyrodella and Ozarkodina and most Palmatolepis, Polygnathus, and Ancyrognathus. Biologic: Coincides with the first appearance of Phoenixites frechi (Goniatite). | 43°28′14″N 3°03′35″E﻿ / ﻿43.4705°N 3.0597°E﻿ / 43.4705; 3.0597 |
| Upper | Frasnian | 382.31 | Col du Puech de la Suque, Montagne Noire, France | Biologic: First appearance of Ancyrodella rotundiloba (Conodont). | 43°30′12″N 3°05′12″E﻿ / ﻿43.5032°N 3.0868°E﻿ / 43.5032; 3.0868 |
| Middle |
| Middle | Givetian | 387.95 | Jebel Mech Irdane, Tafilalt, Morocco | Biologic: First appearance of Polygnathus hemiansatus (Conodont). Biologic: Just below first appearance of Maenioceras (Goniatite). | 31°14′15″N 4°21′15″W﻿ / ﻿31.2374°N 4.3541°W﻿ / 31.2374; -4.3541 |
| Middle | Eifelian | 393.47 | Wetteldorf Richtschnitt section, Wetteldorf, Eifel, Germany | Biologic: First appearance of Polygnathus costatus partitus (Conodont). | 50°08′59″N 6°28′18″E﻿ / ﻿50.1496°N 6.4716°E﻿ / 50.1496; 6.4716 |
| Lower |
| Lower | Emsian | 410.62 | Zinzil'ban Gorge, Uzbekistan | Biologic: First appearance of Polygnathus kitabicus (Conodont). | 39°12′00″N 67°18′20″E﻿ / ﻿39.2000°N 67.3056°E﻿ / 39.2000; 67.3056 |
| Lower | Pragian | 413.02 | Velká Chuchle quarry Velká Chuchle, Prague, Czech Republic | Biologic: First appearance of Eognathodus sulcatus (Conodont). | 50°00′53″N 14°22′21″E﻿ / ﻿50.0147°N 14.3726°E﻿ / 50.0147; 14.3726 |
| Lower | Lochkovian | 419.62 | Klonk, Prague, Czech Republic | Biologic: First appearance of Monograptus uniformis (graptolite). | 49°54′03″N 14°03′40″E﻿ / ﻿49.90083°N 14.06111°E﻿ / 49.90083; 14.06111 |

#### Silurian

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Přídolí | Přídolí | 422.7 | Požáry Section, Řeporyje District, Prague, Czech Republic | Biologic: First appearance of Monograptus parultimus (Graptolite). | 50°01′40″N 14°19′30″E﻿ / ﻿50.0277°N 14.3249°E﻿ / 50.0277; 14.3249 |
| Ludlow |
| Ludlow | Ludfordian | 425 | Sunnyhill, Ludlow, Shropshire, England, U.K. | Imprecise GSSP. Biologic: Near first appearance of Saetograptus leintwardinensis (Graptolite). | 52°21′33″N 2°46′38″W﻿ / ﻿52.3592°N 2.7772°W﻿ / 52.3592; -2.7772 |
| Ludlow | Gorstian | 426.7 | Pitch Coppice, Ludlow, Shropshire, England, U.K. | Biologic: First appearance Saetograptus (Colonograptus) varians | 52°21′33″N 2°46′38″W﻿ / ﻿52.3592°N 2.7772°W﻿ / 52.3592; -2.7772 |
| Wenlock |
| Wenlock | Homerian | 430.6 | Whitwell Coppice, Homer, England, U.K. | Biologic: First appearance of Cyrtograptus lundgreni (Graptolite). | 52°36′56″N 2°33′53″W﻿ / ﻿52.6156°N 2.5647°W﻿ / 52.6156; -2.5647 |
| Wenlock | Sheinwoodian | 432.9 | Hughley Brook, Apedale, England, U.K. | Imprecise GSSP. Will be reexamined. Biologic: Currently between acritarch biozone 5 and last appearance of Pterospathodus amorphognathoides. Candidate boundaries are a conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone. | 52°34′52″N 2°38′20″W﻿ / ﻿52.5811°N 2.6389°W﻿ / 52.5811; -2.6389 |
| Llandovery |
| Llandovery | Telychian | 438.6 | El Pintado section, Province of Seville, Spain | Biologic: FAD of the graptolite Spirograptus guerichi | 37°59′07″N 5°55′43″W﻿ / ﻿37.9853°N 5.9285°W﻿ / 37.9853; -5.9285 |
| Llandovery | Aeronian | 440.5 | Hlásná Třebaň section, Czech Republic | Biologic: First appearance of Demirastrites triangulatus (Graptolite). | 49°55′23″N 14°12′43″E﻿ / ﻿49.9230°N 14.2119°E﻿ / 49.9230; 14.2119 |
| Llandovery | Rhuddanian | 443.1 | Dob's Linn, Moffat, Dumfries-shire, Scotland, U.K. | Biologic: First appearance of Akidograptus ascensus and Parakidograptus acuminatus (Graptolite). 1.6 m above the base of the Birkhill Shale Formation. | 55°26′24″N 3°16′12″W﻿ / ﻿55.4400°N 3.2700°W﻿ / 55.4400; -3.2700 |

#### Ordovician

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Upper |
| Upper | Hirnantian | 445.2 | Wangjiawan section Wangjiawan, Yichang, China | Biologic: First appearance of Normalograptus extraordinarius (Graptolite). Climatic: Base of major positive carbon isotope excursion. Climatic: Beginning of sea-level fall associated with onset of a major glaciation. | 30°59′03″N 111°25′11″E﻿ / ﻿30.9841°N 111.4197°E﻿ / 30.9841; 111.4197 |
| Upper | Katian | 452.8 | Black Knob Ridge section, Oklahoma, United States | Biologic: First appearance of Diplacanthograptus caudatus (Graptolite). Climatic: Just below base of Guttenberg carbon isotope excursion. | 34°25′50″N 96°04′29″W﻿ / ﻿34.4305°N 96.0746°W﻿ / 34.4305; -96.0746 |
| Upper | Sandbian | 458.2 | Fågelsång section Sularp Brook, Skåne, Sweden | Biologic: First appearance of Nemagraptus gracilis (Graptolite). 1.4 m below a phosphorite marker bed. | 55°42′49″N 13°19′32″E﻿ / ﻿55.7137°N 13.3255°E﻿ / 55.7137; 13.3255 |
| Middle |
| Middle | Darriwilian | 469.4 | Huangnitang Section Huangnitang Village, Changshan, Zhejiang, China | Biologic: First appearance of Undulograptus austrodentatus (Graptolite). | 28°51′14″N 118°29′23″E﻿ / ﻿28.8539°N 118.4897°E﻿ / 28.8539; 118.4897 |
| Middle | Dapingian | 471.3 | Huanghuachang section Huanghuachang, Yichang, China | Biologic: Lowest appearance of Baltoniodus triangularis (Conodont). | 30°51′38″N 111°22′26″E﻿ / ﻿30.8605°N 111.3740°E﻿ / 30.8605; 111.3740 |
| Lower |
| Lower | Floian | 477.1 | Diabasbrottet quarry, Västergötland, Sweden | Biologic: Lowest appearance of Tetragraptus approximatus (Graptolite). | 58°21′32″N 12°30′09″E﻿ / ﻿58.3589°N 12.5024°E﻿ / 58.3589; 12.5024 |
| Lower | Tremadocian | 486.85 | Greenpoint section Green Point, Newfoundland, Canada | Biologic: First appearance of Iapetognathus fluctivagus (Conodont). Biologic: Planktonic graptolites occur 4.8 m above boundary. Climatic: Coincides with a peak in carbon isotopes. | 49°40′58″N 57°57′55″W﻿ / ﻿49.6829°N 57.9653°W﻿ / 49.6829; -57.9653 |

#### Cambrian

| Epoch | Stage | Age (mya) | GSSP location | Defining markers | Geographic Coordinates | References |
| Furongian |
| Furongian | Stage 10 | 491 | Candidate sections: Duibian, Zhejiang, China Lawson Cove, Utah, United States | Candidates: Biologic: First appearance of Lotagnostus americanus (Trilobite). Biologic: First appearance of Cordylodus andresi (Conodont). Biologic: First appearance of Eoconodontus notchpeakensis (Conodont). | - | |
| Furongian | Jiangshanian | ~494.2 | Duibian B Section Duibian, Zhejiang, China | Biologic: First appearance of Agnostotes orientalis (Trilobite). | 28°48′57″N 118°36′54″E﻿ / ﻿28.815967°N 118.614933°E﻿ / 28.815967; 118.614933 | |
| Furongian | Paibian | ~497 | Paibi section Paibi, Hunan, China | Biologic: First appearance of the agnostoid Glyptagnostus reticulatus (Trilobite). Climatic: Coincides with base of the Steptoean positive carbon isotope excursion (SPICE). | 28°23′22″N 109°31′33″E﻿ / ﻿28.3895°N 109.5257°E﻿ / 28.3895; 109.5257 | |
| Miaolingian |
| Miaolingian | Guzhangian | ~500.5 | Luoyixi section Luoyixi, Guzhang, Hunan, China | Biologic: First appearance of Lejopyge laevigata (Trilobite). | 28°43′12″N 109°57′53″E﻿ / ﻿28.7200°N 109.9647°E﻿ / 28.7200; 109.9647 | |
| Miaolingian | Drumian | ~504.5 | Drumian section Wheeler Shale, Utah, U.S.A. | Biologic: First appearance of Ptychagnostus atavus (Trilobite). | 39°30′42″N 112°59′29″W﻿ / ﻿39.5117°N 112.9915°W﻿ / 39.5117; -112.9915 | |
| Miaolingian | Wuliuan | ~506.5 | Wuliu-Zengjiayan, Guizhou, China | Biologic: First appearance of Oryctocephalus indicus (Trilobite). | 26°04′51″N 108°24′50″E﻿ / ﻿26.0807°N 108.4138°E﻿ / 26.0807; 108.4138 | |
| Series 2 |
| Series 2 | Stage 4 | ~514.5 | None | Biologic: First appearance Arthricocephalus chauveaui (Trilobite species). Biologic: First appearance Olenellus or Redlichia (Trilobite genera). | - | |
| Series 2 | Stage 3 | ~521 | None | Biologic: First appearance of trilobites (possibly Lemdadella) | - | |
| Terreneuvian |
| Terreneuvian | Stage 2 | ~529 | None | Biologic: First appearance of small shelly fauna or archaeocyathids | - | - |
| Terreneuvian | Fortunian | 538.8 | Fortune head section, Newfoundland, Canada | Biologic: First appearance of Treptichnus pedum (trace fossil). | 47°04′34″N 55°49′52″W﻿ / ﻿47.0762°N 55.8310°W﻿ / 47.0762; -55.8310 | |

### Precambrian
#### Proterozoic

| Era | Period | Age (mya) | GSSP location | Defining markers | Geographic Coordinates |
| Neoproterozoic |
| Neoproterozoic | Ediacaran | ~635 | Enorama Creek section Flinders Ranges, South Australia | Geologic: Worldwide distinct cap carbonates. Isotopic: Beginning of a distinctive pattern of secular changes in carbon isotopes. | 31°19′53″S 138°38′00″E﻿ / ﻿31.3314°S 138.6334°E﻿ / -31.3314; 138.6334 |
| Neoproterozoic | Cryogenian | ~720 | 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 | 1000 | Defined chronometrically | - | - |
| Mesoproterozoic |
| Mesoproterozoic | Stenian | 1200 | Defined chronometrically | - | - |
| Mesoproterozoic | Ectasian | 1400 | Defined chronometrically | - | - |
| Mesoproterozoic | Calymmian | 1600 | Defined chronometrically | - | - |
| Paleoproterozoic |
| Paleoproterozoic | Statherian | 1800 | Defined chronometrically | - | - |
| Paleoproterozoic | Orosirian | 2050 | Defined chronometrically | - | - |
| Paleoproterozoic | Rhyacian | 2300 | Defined chronometrically | - | - |
| Paleoproterozoic | Siderian | 2500 | Defined chronometrically | - | - |

#### Archean and Hadean

| Eon | Era | Age (mya) | GSSP/GSSA location | Defining markers | Geographic Coordinates | References |
| Archean |
| Archean | Neoarchean | 2800 | - | Defined chronometrically | - | - |
| Archean | Mesoarchean | 3200 | - | Defined chronometrically | - | - |
| Archean | Paleoarchean | 3600 | - | Defined chronometrically | - | - |
| Archean | Eoarchean | 4031 | Along the Acasta River, Northwest Territories, Canada | Defined chronometrically Ten oldest U-Pb zircon ages | 65°10′26″N 115°33′14″W﻿ / ﻿65.1738°N 115.5538°W﻿ / 65.1738; -115.5538 | |
| Hadean | - | 4567.3 | - | Defined chronometrically Formation of the Solar System | - | |