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) Status GSSP location Defining markers Geographic Coordinates References HoloceneMeghalayan Mawmluh Cave, Meghalaya, India Climatic: 4.2-kiloyear event. Northgrippian NGRIP1 ice core, Greenland Climatic: 8.2-kiloyear event. Greenlandian NGRIP2 ice core, Greenland Climatic: End of the Younger Dryas stadial. PleistoceneUpper/Late - Climatic: Marine Isotope Substage 5e - - Chibanian Chiba, Japan Magnetic: Brunhes-Matuyama magnetic reversal. Calabrian 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. Gelasian Monte San Nicola Section, Gela, Sicily, Italy Magnetic: Base of magnetic polarity chronozone C2r (Matuyama). Biologic: Extinction of Discoaster pentaradiatus and Discoaster surculus (Haptophyte).
Neogene
Epoch Stage Age (mya) Status GSSP location Defining markers Geographic Coordinates References Pliocene Piacenzian 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). Zanclean 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). Miocene Messinian 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). Tortonian 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. Serravallian 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). 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 (Planktonic foraminifera). Burdigalian 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 - Aquitanian Lemme-Carrosio Section, Carrosio, Italy Magnetic: Base of magnetic polarity chronozone C6Cn.2n. Biologic: Near first appearance of Paragloborotalia kugleri (Planktonic foraminifera).
Paleogene
Epoch Stage Age (mya) Status GSSP location Defining markers Geographic Coordinates References Oligocene Chattian Monte Cagnero, Central Apennines, Italy Biological: last occurrence of the planktonic foraminifer Chiloguembelina (Base of Foram Zone P21b) Rupelian Massignano quarry section, Massignano, Ancona, Italy Biologic: Extinction of Hantkenina and Cribrohantkenina (Planktonic foraminifera). 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 Bartonian Contessa highway section Gubbio, Central Apennines, Italy Biologic: Near Extinction of Reticulofenestra reticulata (Haptophyte) - Lutetian Gorrondatxe sea-cliff section,
Western Pyrenees, Basque Country, Spain Biologic: First appearance of Hantkenina (Planktonic foraminifera). Ypresian Dababiya section, Luxor, Egypt Climatic: Base of negative Carbon Isotope Excursion (CIE). Paleocene Thanetian Zumaia Section, Basque Country, Spain Magnetic: Base of magnetic polarity chronozone C26n. 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 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 (mya) Status GSSP location Defining markers Geographic Coordinates References Upper Maastrichtian Grande Carrière quarry, Landes, France Biologic: 12 biostratigraphic criteria Biologic: First appearance of Pachydiscus neubergicus (Ammonite) is just above the boundary. Campanian Bottaccione, Gubbio, Italy Magnetic: Base of Chron C33r. Santonian Olazagutia, Spain Biologic: First appearance of Cladoceramus undulatoplicatus (Inoceramid bivalve). Coniacian Salzgitter-Salder quarry, Germany Biologic: First appearance of Cremnoceramus rotundatus (Inoceramid bivalve). Turonian Rock Canyon, Colorado, United States Biologic: First appearance of Watinoceras devonense (Ammonite). Cenomanian Mont Risoux, Hautes-Alpes, France Biologic: First appearance of Rotalipora globotruncanoides (Planktonic foraminifera) Lower Albian Col de Pré-Guittard section, Arnayon, Drôme, France Biologic: first appearance of the planktonic foraminiferan Microhedbergella renilaevis. Aptian Candidate section: Gorgo a Cerbara, Piobbico, Central Apennines, Italy Magnetic: Base of magnetic polarity chronozone M0r. Biologic: Near first appearance of Paradeshayesites oglanlensis (Ammonite). - - Barremian Río Argos, Caravaca de la Cruz, Murcia Province, Spain Biologic: First appearance of Ammonite Taveraidiscus hugii. - Hauterivian La Charce, Drôme, France Biologic: First appearance of the Ammonite genus Acanthodiscus. Valanginian Montbrun-les-Bains, Drôme, France Biologic: First appearance of Thurmanniceras pertransiens (Ammonite). Berriasian Candidate section: Vaca Muerta, Neuquén Basin, ArgentinaThe Jurassic-Cretaceous boundary in the High Andes of Mendoza: New geochronological constraintsCandidates: Magnetic—base of Chron M18r Base of Calpionellid zone B
Jurassic
Epoch Stage Age (mya) Status GSSP location Defining markers Geographic Coordinates References 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 (Ammonite). Biologic: First appearance of genus Gravesia (Ammonite). - - Kimmeridgian Flodigarry, Isle of Skye, Scotland, U.K. Biologic: First appearance of Pictonia baylei (Ammonite). Oxfordian Candidate sections: Redcliff Point, Dorset, England, U.K. Savouron, Provence, France Biologic: Horizon of Cardioceras redcliffense (Ammonite). - - Middle Callovian Candidate sections: Pfeffingen, Swabian Alb, Germany Russia Biologic: First appearance of genus Kepplerites (Ammonite). - - Bathonian Ravin du Bès, Bas-Auran, Alpes de Haute, France Biologic: First appearance of Gonolkites convergen (Ammonite). Bajocian Cabo Mondego, Portugal Biologic: First appearance of Hyperlioceras mundum, Hyperlioceras furcatum, Braunsina aspera, and Braunsina elegantula(Ammonite) Biologic: First appearance of genus Hyperlioceras (Ammonite). Aalenian Fuentelsaz, Spain Biologic: First appearance of Leioceras opalinum and Leioceras lineatum Biologic: First appearance of genus Leioceras (Ammonite). Lower Toarcian Peniche, Portugal Biologic: First appearance of D. (E.) simplex (Ammonite). Pliensbachian Robin Hood's Bay, Yorkshire, England, U.K. Biologic: First appearance of Bifericeras donovani and genera Apoderoceras (Ammonite). Sinemurian East Quantoxhead, West Somerset, England, UK Biologic: First appearance of the Vermiceras quantoxense, Vermiceras palmeri (Ammonite). Hettangian Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria Biologic: Near first appearance of smooth Psiloceras spela group (Ammonite).
Triassic
Epoch Stage Age (mya) Status GSSP location Defining markers Geographic Coordinates References Upper Rhaetian ~ 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). - - 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. - - Carnian ~ 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. Middle Ladinian Bagolino, Lombardian pre-Alps, Italy Biologic: First appearance of Eoprotrachyceras curionii (Ammonite). Biologic: First appearance of Budurovignathus praehungaricus (Conodont). Anisian Candidate sections: Desli Caira, Northern Dobruja, Romania Guandao, Guizhou, China Biologic: First appearance of Chiosella timorensis (Conodont). Magnetic: Base of magnetic zone MT1n. Lower Olenekian Candidate sections: Mud (Muth) village, Spiti valley, India Chaohu, China Biologic: First appearance of Neospathodus waageni (Conodont).