Overview of Global Boundary Stratotype Sections and Points (GSSP's)

Status on 2007, compiled by Jim Ogg (ICS Executive Secretary)

EON, Era, System, Series, Stages Age (Ma)
GTS 2004
Est.
±Ma
Derivation of age Principal correlative events GSSP and location Status Publication
PHANEROZOIC Eon
Cenozoic Era
Quaternary System
2.588
-
Quaternary is recommended as a formal Period/System of the Cenozoic. It is the interval of oscillating climatic extremes (glacial and interglacial episodes) that was initiated at about 2.6 Ma (set equal to base of Gelasian stage), therefore it encompasses the Holocene and Pleistocene epochs and the late Pliocene. Equivalent to GSSP of Gelasian at Monte San Nicola, Gela, Sicily, Italy. Correlates with marine isotopic stage 103, and base of magnetic polarity Chron C2r (Matuyama). ICS and INQUA recommendation to IUGS; May 2007. IUGS has tabled formalizing Quaternary until late 2008 Proposed definition in Episodes 28 (2), p.118-120, 2005 (although sub-era rank was not accepted)
Holocene Series
base Holocene 0.011784 0.00 Annual layer counting in ice core ("ka" is relative to AD2000); counting uncertainy is 69 years Cllimatic -- End of the Younger Dryas cold spell, which is reflected in a shift in deuterium excess values, followed closely by changes in d18O, dust concentration, a range of chemical species, and by a change in annual layer thickness NorthGRIP ice core, Greenland
(75.1°N, 42.32°W)
GSSP anticipated in 2008
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Pleistocene Series
base Tarantian Stage 0.126 0.00 Astronomical cycles in sediments Climatic -- Base of the Eemian interglacial stage (= base of marine isotope stage 5e) before final glacial episode of Pleistocene. Base of Tyrrhrenian regional stage of Mediterranean Amsterdam-Terminal borehole (63.5 m below surface), Netherlands
(52°22'45"N, 4°54'52"E)
GSSP anticipated in 2008
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base Ionian Stage 0.781 0.00 Astronomical cycles in sediments Magnetic -- Brunhes-Matuyama magnetic reversal (base of Chron 1n) Candidate sections in Italy (Montalbano Jorica or Valle di Manche) and Japan (Chiba) GSSP anticipated in 2009
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base Calabrian Stage 1.806 0.00 Astronomical cycles in sediments Magnetic -- Just above top of magnetic polarity Chron C2n (Olduvai) and the extinction level of calcareous nannofossil Discoaster brouweri (base Zone CN13). Above are lowest occurrence of calcareous nannofossil Gephyrocapsa spp. (medium-sized morphotype) and extinction level of planktonic foraminifer Globigerinoides extremus Top of sapropel layer 'e' in the Vrica section, Calabria, Italy
(39°02'18.61"N, 17°08'05.79"E)
Ratified 1985 Episodes 8 (2), p.116-120, 1985
base Gelasian Stage 2.588 0.00 Astronomical cycles in sediments Magnetic -- Base of magnetic polarity Chron C2r (Matuyama). Marine isotopic stage 103. Above are extinction levels of calcareous nannofossil Discoaster pentaradiatus and D. surculus (base Zone CN12c) Midpoint of sapropelic Nicola Bed ("A5"), Monte San Nicola, Gela, Sicily, Italy
(37°08'48.8"N*, 14°12'12.6"E*)
Ratified 1996 Episodes 21 (2), p.82-87, 1998
Neogene System
Pliocene Series
base Piacenzian Stage 3.600 0.00 Astronomical cycles in sediments Magnetic -- Base of Gauss magnetic polarity Chron C2An (Gauss); extinction levels of planktonic foraminifers Globorotalia margaritae (base Zone PL3) and Pulleniatina primalis Base of beige layer of carbonate cycle 77, Punta Piccola, Sicily, Italy
(37°17'20"N*, 13°29"36"E*)
Ratified 1997 Episodes 21 (2), p.88-93, 1998
base Zanclean Stage, base Pliocene Series 5.332 0.00 Astronomical cycles in sediments Magnetic -- Top of magnetic polarity Chron C3r, ~100 kyr before Thvera normal-polarity subchronozone (Chron C3n.4n). Calcareous nannofossils -- near extinction level of Triquetrorhabdulus rugosus (base Zone CN10b) and the lowest occurrence of Ceratolithus acutus Base of Trubi Fm (base of carbonate cycle 1; insolation cycle 510 from the present), Eraclea Minoa, Sicily, Italy Ratified 2000 Episodes 23 (3), p.179-187, 2000
Miocene Series
base Messinian Stage 7.246 0.00 Astronomical cycles in sediments Planktonic Foraminifer -- Lowest regular occurrence of the Globorotalia conomiozea group; middle of magnetic polarity Chron C3Br.1r Base of red layer of carbonate cycle 15, Oued Akrech, Rabat, Morocco
(33°56'13"N, 6°48'45"W)
Ratified 2000 Episodes 23 (3), p. 172-178, 2000
base Tortonian Stage 11.608 0.00 Astronomical cycles in sediments Microfossils -- Last Common Occurrences of the calcareous nannofossil Discoaster kugleri and the planktonic foraminifer Globigerinoides subquadratus. Associated with the short normal-polarity Chron C5r.2n Midpoint of sapropel 76, Monte dei Corvi beach section, Ancona, Italy
(43°35'12"N, 13°34'10"E)
Ratified 2003 Episodes 28 (1), p.6-17, 2005
base Serravallian Stage 13.82 0.00 Astronomical cycles in sediments Climatic -- Mi3b isotopic event (global cooling episode) in upper magnetic polarity chronozone C5ACn. Above (13.65 Ma) is the lowest occurrence of nannofossil Sphenolithus heteromorphus (previously considered base of Serravallian). Base of Blue Clay Formation, Ras il Pellegrin coastal section, Fomm Ir-Rih Bay, west Malta
(35°54'50"N, 14°20'10"E)
Ratified 2006
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base Langhian Stage 15.97 0.00 Calibrated magnetic anomaly scale Planktonic foraminifer -- Near first occurrence of Praeorbulina glomerosa and top of magnetic polarity Chron C5Cn.1n
Potentially in astronomically-tuned ODP core
GSSP anticipated in 2008
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base Burdigalian Stage 20.43 0.00 Calibrated magnetic anomaly scale Planktonic foraminifer -- Near lowest occurrence of Globigerinoides altiaperturus or near top of magnetic polarity Chron C6An
Potentially in astronomically-tuned ODP core
Guide event is undecided. GSSP anticipated in 2008
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base Aquitanian Stage, base Miocene Series, base Neogene System 23.03 0.00 Astronomical cycles in sediments Multiple -- Base of magnetic polarity Chron C6Cn.2n; lowest occurrence of planktonic foraminifer Paragloborotalia kugleri; near extinction of calcareous nannofossil Reticulofenestra bisecta (base Zone NN1); Oxygen isotopic event Mi-1 35 m from top of Lemme-Carrosio section, Carrosio village, north of Genoa, Italy
(44°39'32"N, 08°50'11"E)
Ratified 1996 Episodes 20 (1),p. 23-28, 1997
Paleogene System
Oligocene Series
base Chattian Stage 28.4 0.1 Calibrated magnetic anomaly scale relative to base-Miocene and C24n. Arbitrary 100 kyr uncertainty assigned. Potentially extinction of planktonic foraminifer Chiloguembelina (base Foram Zone P21b); or an isotopic/climatic event Monte Cagnero (Umbria-Marche region, Italy) GSSP anticipated in 2008
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base Rupelian Stage, base Oligocene Series 33.9 0.1 Calibrated magnetic anomaly scale relative to base-Miocene and C24n. Planktonic foraminifer -- extinction of Hantkenina Base of marl bed at 19m above base of Massignano quarry, Ancona, Italy
(43°31'58.2"N*, 13°36'03.8"E*)
Ratified 1992 Episodes 16 (3), p.379-382, 1993
Eocene Series
base Priabonian Stage 37.2 0.1 Calibrated magnetic anomaly scale relative to base-Miocene and C24n Potentially near lowest occurrence of calcareous nannofossil Chiasmolithus oamaruensis (base Zone NP18) Tiziano Bed, Alano section (Piave River; Veneto Prealps, Belluno province, N. Italy) GSSP anticipated in 2008
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base Bartonian Stage 40.4 0.2 Calibrated magnetic anomaly scale relative to base-Miocene and C24n Potentially near base of magnetic polarity Chron C19n, or extinction of calcareous nannofossil Reticulofenestra reticulata
Contessa highway section near Gubio, Central Apennines, Italy
GSSP anticipated in 2008
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base Lutetian Stage 48.6 0.2 Calibrated magnetic anomaly scale relative to base-Miocene and C24n Potentially a planktonic foraminifer (lowest occurrence of Hantkenina), or magnetic polarity chronozone. [Events traditionally thought to be synchronous and used to place the base-Lutetian are now known to occur at different levels.] Leading candidates are Gorrondatxe beach section, W Pyrenees, Basque country (Spain) and Agost section, Murcia province, Betic Cordilleras (Spain) GSSP anticipated in 2008
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base Ypresian Stage, base Eocene Series 55.8 0.2 Astronomical cycles in sediments scaled from base-Paleocene Geochemical -- Base of negative carbon-isotope excursion Dababiya Section near Luxor, Egypt Ratified 2003 Micropaleontology v.49 (Suppl. 1), 2003. Episodes 30 (4), 2007
Paleocene Series
base Thanetian Stage 58.7 0.2 Astronomical cycles in sediments scaled from base Paleocene, using base of magnetic polarity chronozone C26n. Arbitrary 0.1 (2 precession cycles, plus the base-Paleogene radiometric) uncertainty assigned to all estimates. Magnetic polarity chronozone, base of C26n Leading candidate is Zumaya section, northern Spain GSSP anticipated in 2009
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base Selandian Stage 61.1 0.2 Astronomical cycles in sediments scaled from base Paleocene, using magnetic polarity chronozone placement of C26r Geochemical -- Onset of a carbon isotope shift and sea-level drop (Exxon/Hardenbol sequence boundary "Se1"); near diversification of the Fasciculith group of calcareous nannoplankton, preceding the lowest Fasciculithus tympaniformis (base of nannoplankton zone NP5). Approximately 0.65 myr (ca. 33 precession cycles) above the base of magnetic polarity Chron C26r Base of the red marls of Itzurun Formation in the Zumaia section at San Telmo Beach (N. Spain)
(43º18'02"N, 2º15'34"W)
GSSP anticipated in early 2008
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base Danian Stage, base Paleogene System, base Cenozoic 65.5 0.3 Ar-Ar age suite. However, U-Pb ages are reported to be slightly older than 66 Ma Geochemical -- Iridium geochemical anomaly. Associated with a major extinction horizon (foraminifers, calcareous nannofossils, dinosaurs, etc.) Base of boundary clay, El Kef, Tunisia (but deterioration may require assigning a replacement section)
(36°09'13.2"N, 8°38'54.8"E)
Ratified 1991 Episodes, 29(4), p. 263-278,2006
Mesozoic Era
Cretaceous System
Most Cretaceous substages also have recommended GSSP criteria
Upper Cretaceous Series
base Maastrichtian Stage 70.6 0.6 Estimated placement relative to Ar-Ar calibrated Sr-curve Mean of 12 biostratigraphic criteria of equal importance. Closely above is lowest occurrence of ammonite Pachydiscus neubergicus. Boreal proxy is lowest occurrence of belemnite Belemnella lanceolata. 115.2 m level in Grande Carrière quarry, Tercis-les-Bains, Landes province, SW France
(43°40'46.1"N*, 1°06'47.9"W*)
Ratified 2001 Episodes 24 (4), p.229-238, 2001;
Odin (ed.) IUGS Spec. Publ. Series, v.36, Elsevier, 910pp.
base Campanian Stage 83.5 0.7 Spline fit of Ar-Ar ages and ammonite zones. Crinoid, extinction of Marsupites testudinarius Leading candidates are in west of Seafprd Head (southern England) and Waxahacie dam spillway (north-central Texas) GSSP anticipated in 2008
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base Santonian Stage 85.8 0.7 Spline fit of Ar-Ar ages and ammonite zones. Inoceramid bivalve, lowest occurrence of Cladoceramus undulatoplicatus Leading candidates are Olazagutia (Spain) and Ten-Mile Creek (Texas) GSSP anticipated in 2008
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base Coniacian Stage 89.3 1.0 Spline fit of Ar-Ar ages and ammonite zones. Inoceramid bivalve, lowest occurrence of Cremnoceramus rotundatus (sensu Tröger non Fiege) Leading candidates are in central Poland (Slupia Nadbrzena), USA (Pueblo, Colorado), and Germany (Salzgitter-Salder Quarry) GSSP anticipated in 2008
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base Turonian Stage 93.6 0.8 Spline fit of Ar-Ar ages and ammonite zones Ammonite, lowest occurrence of Watinoceras devonense Base of Bed 86, Rock Canyon Anticline, west of Pueblo, Colorado, west-central USA
(38°16'56"N*, 104°43'39"W*)
Ratified 2003 Episodes 28(2), p. 93-104, 2005
base Cenomanian Stage 99.6 0.9 Spline fit of Ar-Ar ages and ammonite zones, plus monitor standard correction. Then cycle stratigraphy to place foraminifer datum relative to ammonite zonation. Planktonic foraminifer, lowest occurrence of Rotalipora globotruncanoides 36 m below top of Marnes Bleues Formation, Mont Risou, Rosans, Haute-Alpes, SE France
(44°23'33"N, 5°30'43"E)
Ratified 2002 Episodes 27 (1), p.21-32, 2004
Lower Cretaceous Series
base Albian Stage 112.0 1.0 Cycle-stratigraphy of FAD of P. columnata relative to base of Cenomanian, with large uncertainty due to lack of GSSP criteria Candidates include: (1) calcareous nannofossil, lowest occurrence of Praediscosphaera columnata (= P. cretacea of some earlier studies), (2) carbon-isotope excursion (black-shale episode), (3) ammonite Southeastern France Guide event is undecided. GSSP anticipated in 2008
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base Aptian Stage 125.0 1.0 Base of M0r, as recomputed from Ar-Ar age from MIT guyot Magnetic -- base of Chron M0r; near base of Paradeshayesites oglanlensis ammonite zone Leading candidate is Gorgo a Cerbara, Piobbico, Umbria-Marche, central Italy GSSP anticipated in 2008
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base Barremian Stage 130.0 1.5 Pacific spreading model for magnetic anomaly ages (variable rate), using placement at M5n.8. Ammonite -- lowest occurrence of Spitidiscus [now Taveraidiscus] hugii – Spitidiscus vandeckii group Río Argos near Caravaca, Murcia province, S. Spain GSSP anticipated in 2008
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base Hauterivian Stage 133.9 2.0 Pacific spreading model for magnetic anomaly ages (variable rate), using placement at base M11n Ammonite -- lowest occurrence of genus Acanthodiscus (especially A. radiatus) Leading candidate is La Charce village, Drôme province, southeast France GSSP anticipated in 2008
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base Valanginian Stage 140.2 3.0 Pacific spreading model for magnetic anomaly ages (variable rate), using placement at M14r.3 (base T. pertransiens). Calpionellid -- lowest occurrence of Calpionellites darderi (base of Calpionellid Zone E); followed by the lowest occurrence of ammonite “Thurmanniceras” pertransiens Leading candidates are near Montbrun-les-Bains (Drôme province, SE France) and Rio Argos (S. Spain) GSSP anticipated in 2008
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base Berriasian Stage, base Cretaceous System 145.5 4.0 Pacific spreading model for magnetic anomaly ages (variable rate), assigning to base of Berriasella jacobi zone (M19n.2n.55) Maybe near lowest occurrence of ammonite Berriasella jacobi
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Guide event is undecided. GSSP anticipated in 2009
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Jurassic System
Upper Jurassic Series
base Tithonian Stage 150.8 4.0 Pacific spreading model for magnetic anomaly ages (variable rate), age is provisionally assigned as base M26r.2 Maybe near base of Hybonoticeras hybonotum ammonite zone and lowest occurrence of Gravesia genus, and the base of magnetic polarity Chron M22An Candidates are Pfeffingen (Swabian Alb, SW Germany) and in Russia Guide event is undecided. GSSP anticipated in 2008
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base Kimmeridgian Stage 155.6 4.0 Pacific spreading model for magnetic anomaly ages (variable rate), assigning to base M26r.2 (Boreal ammonite definition) Ammonite -- base of Pictonia baylei ammonite zone of Boreal realm Flodigarry (Isle of Skye, NW Scotland)
(57.6°N, 6.2°W)
GSSP anticipated in 2008
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base Oxfordian Stage 161.2 4.0 Pacific spreading model for magnetic anomaly ages (variable rate), assigning to base M36An Ammonite -- Cardioceras redcliffense Horizon at base of the Cardioceras scarburgense Subzone (defines base of Quenstedtoceras mariae Zone) Candidates are Redcliff Point (Dorset, SW England) and Savouron (Provence province, SE France) GSSP anticipated in 2008
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Middle Jurassic Series
base Callovian Stage 164.7 4.0 Equal subzones scale Bajo-Bath-Callov Ammonite -- lowest occurrence of the genus Kepplerites (Kosmoceratidae) (defines base of Macrocephalites herveyi Zone in sub-Boreal province of Great Britain to southwest Germany) Candidates are Pfeffingen (Swabian Alb, SW Germany) and in Russia GSSP anticipated in 2008
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base Bathonian Stage 167.7 3.5 Equal subzones scale Bajo-Bath-Callov Ammonite -- lowest occurrence of Parkinsonia (G.) convergens (defines base of Zigzagiceras zigzag Zone) Candidates are in Iberia, and Ravin du Bès near Digne (Hautes-Alpes, SE France) GSSP anticipated in 2008
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base Bajocian Stage 171.6 3.0 Equal subzones scale Bajo-Bath-Callov Ammonite, lowest occurrence of the genus Hyperlioceras (defines base of the Hyperlioceras discites Zone) Base of Bed AB11, 77.8 m above base of Murtinheira section, Cabo Mondego, western Portugal. [Auxiliary is at Bearreraig, Isle of Skye, Scotland.]
(40°11'57"N*, 8°54'15"W*)
Ratified 1996 Episodes 20 (1), p.16-22, 1997
base Aalenian Stage 175.6 2.0 Duration of Aalenian-Toarcian from cycle stratigraphy Ammonite, lowest occurrence of Leioceras genus base of Bed FZ107, Fuentelsalz, central Spain
(41°10'15"N, 1°50'W)
Ratified 2000 Episodes 24 (3), p.166-175, 2001
Lower Jurassic Series
base Toarcian Stage 183.0 1.5 Duration of Aalenian-Toarcian from cycle stratigraphy Ammonite -- near lowest occurrence of a diversified Eodactylites ammonite fauna; correlates with the NW European Paltus horizon.
Peniche (Portugal)
GSSP anticipated in 2008
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base Pliensbachian Stage 189.6 1.5 Cycle-scaled linear Sr trend Ammonite -- lowest occurrences of Bifericeras donovani and of genera Apoderoceras (defines base of Phricodoceras taylori subzone of Uptonia jamesoni ammonite zone) Base of Bed 73b, Wine Haven section, Robin Hood's Bay, Yorkshire, England, UK
(54°24'25"N, 0°29'51"W)
Ratified 2005 Episodes 29 (2), p.93-106, 2006
base Sinemurian Stage 196.5 1.0 Cycle-scaled linear Sr trend Ammonite -- lowest occurrence of arietitid genera Vermiceras and Metophioceras 0.9 m above base of Bed 145, East Quantoxhead, Watchet, West Somerset, SW England, UK
(51°11'27.3"N*, 3°14'11.2"W*)
Ratified 2000 Episodes 25 (1), p. 22-26, 2002
base Hettangian Stage, base Jurassic System 199.6 0.6 U-Pb age just below proposed GSSP for base-Jurassic in British Columbia Near lowest occurrence of Psiloceras ammonite group; associated with a carbon-isotope excursion Leading candidate is New York Canyon (Nevada, USA) with Kunga Island (British Columbia, Canada) as auxiliary. Other candidate is St. Audries' Bay (Somerset, UK) Guide event is undecided. GSSP anticipated in 2008
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Triassic System
Upper Triassic Series
base Rhaetian Stage 203.6 1.5 Magnetostratigraphic correlation to cycle-scaled Newark magnetic polarity pattern Near lowest occurrence of ammonite Cochlocera, conodonts Misikella spp. and Epigondolella mosheri, and radiolarian Proparvicingula moniliformis Key sections in Austria, British Columbia (Canada), and Turkey Guide event is undecided. GSSP anticipated in 2008
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base Norian Stage 216.5 2.0 Magnetostratigraphic correlation to cycle-scaled Newark magnetic polarity pattern. However, revised correlations suggest 228.8 Ma Ammonoid -- Base of Stikinoceras kerri ammonoid zone; near the appearance of Metapolygnathus echinatus within the M. communisti conodont zone Candidates are Black Bear Ridge (Williston Lake, British Columbia, Canada) and Pizzo Mondello (Sicily, Italy) Guide event is undecided. GSSP anticipated in 2008
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base Carnian Stage 228.7 2.0 Magnetostratigraphic correlation to cycle-scaled Newark magnetic polarity pattern. However, revised correlations suggest 236.8 Ma Ammonoid -- lowest occurrence of Daxatina (base of D. canadesis subzone of Trachyceras Zone). Near appearances of conodont Metapolygnathus polygnathiformis noah and of Halobia bivalves. Just above base of S2n magnetic polarity zone and above the maximum flooding surface of Sequence Lad 3 of Hardenbol et al (1998) Candidate GSSP is base of marly limestone bed SW4, 45m from base of San Cassiano Fm, Prati di Stuores/Stuores Wiesen mountain-side section, 4.5 km south of S. Cassiano town, Dolomites, N. Italy. Important reference sections in New Pass (Nevada, USA).and Spiti (India)
(46°31'37"N, 11°55'49"E)
GSSP submitted 2008 Albertiana 36, Dec 2007
Middle Triassic Series
base Ladinian Stage 237.0 2.0 U-Pb array by Mundil et al. on levels near Nevadites (= Secedensis) ammonite zone in Dolomites, plus placement relative to magnetostratigraphy correlations to cycle-scaled Newark magnetic polarity pattern. However, revised correlations and zircon processing suggest 240.5 Ma Ammonoid -- lowest occurrence of the Eoprotrachyceras curionii (base of the E. curionii zone); onset of the Trachyceratidae family. Above lowest Budurovignathus praehungaricus conodont Top of "Chiesense groove", 5m above base of Buchenstein Beds, Caffaro river bed, Bagolino (Brescia province, N. Italy)
(45°49'9.5"N, 10°28'15.5"E)
Ratified 2005 Episodes 28 (4), 233-244, 2005
base Anisian Stage 245.0 1.5 Cycle-stratigraphy scaled to base-Triassic. However, revised zircon processing at P/Tr suggest 251.0 Ma Either Conodont -- profound turnover including lowest occurrences of Chiosella (Cs. gondolloides followed by Cs. timorensis), or Magnetic -- base of magnetic normal-polarity chronozone MT1n between those two conodont levels. Near base of Paracrochordiceras-Japonites ammonite beds Candidate GSSP is Desli Caira hill Section B, 17 km south of Tulcea city, northern Dobrogea province, Romania. In Section B, the GSSP level will be either the FAD of conodont Cs. timorensis at the base of Bed GR7 at ca. 7 m; OR the base of magnetozone MT1n at the 5.7 m level. Guandao (Guizhou province, China) as another candidate
(45°04'27"N, 28°48'08"E)
GSSP anticipated in 2008 Albertiana 36, Dec 2007
Lower Triassic Series
base Olenekian Stage 249.5 0.7 Cycle-stratigraphy scaled to base-Triassic. However, revised zircon processing at P/Tr suggest 251 Ma Conodont -- lowest occurrence of Neospathodus waageni s.l., 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 Candidate GSSP is base of Bed 13A-2, about 4.8m up in Mikin Fm., Section M04 (~4000 m elevation), ~1 km NE of Mud (Muth) village, Spiti valley, northwest India
(31°57'55.5"N, 78°01'28.5"E)
GSSP submitted in 2008 Albertiana 36, Dec 2007
base Induan Stage, base Triassic System, base Mesozoic 251.0 0.4 Average of U-Pb constraints from Bowring et al. (1998). However, revised processing for U-Pb ages suggest 252.5 Ma Conodont -- lowest occurrence of Hindeodus parvus; termination of major negative carbon-isotope excursion. This level is after peak of Late Permian extinctions
(31°4'47.28"N, 119°42'20.90"E)
Base of Bed 27c, Meishan, Zhejiang, China Ratified 2001 Episodes 24 (2), p.102-114, 2001
Paleozoic Era
Permian System
Lopingian Series
base Changhsingian Stage 253.8 0.7 Permian-Carboniferous time scale is derived from calibrating a master composite section to selected radiometric ages Conodont -- near lowest occurrence of conodont Clarkina wangi Base of Bed 4a-2, 88 cm above base of Changxing Limestone, Meishan D section (Zhejiang province, E. China)
(31°4'55"N, 119°42'22.9"E)
Ratified 2005
Episodes 29(3), p. 175–182, 2006
base Wuchiapingian Stage 260.4 0.7
"
Conodont -- lowest occurrence of Clarkina postbitteri postbitteri Base of Bed 6K/115 in Penglaitan section, S. bank of Hongshui River, 20 km ESE of Laibin country town (Guangxi province, S. China). Nearby Tieqiao (Rail-bridge) section is a supplementary reference section
(23°41"43"N, 109°19"16"E)
Ratified 2004 Episodes 29(4), p.253-262, 2006
Guadalupian Series
base Capitanian Stage 265.8 0.7
"
Conodont -- lowest occurrence of Jinogondolella postserrata 4.5 m above base of Pinery Limestone Member, Nipple Hill, SE Guadalupe Mountains, Texas, USA
(31°54'32.8"N, 104°47'21.1"W)
Ratified 2001 Episodes article in preparation
base Wordian Stage 268.0 0.7
"
Conodont, lowest occurrence of Jinogondolella aserrata 7.6 m above base of Getaway Ledge outcrop, Guadalupe Pass, SE Guadalupe Mountains, Texas, USA
(31°51'56.9"N, 104°49'58.1"W)
Ratified 2001 Episodes article in preparation
base Roadian Stage 270.6 0.7
"
Conodont, lowest occurrence of Jinogondolella nanginkensis 42.7 m above base of Cutoff Formation, Stratotype Canyon, southern Guadalupe Mountains, Texas, USA
(31°52'36.1"N, 104°52'36.5"W)
Ratified 2001 Episodes article in preparation
Cisuralian Series
base Kungurian Stage 275.6 0.7
"
Conodont -- near lowest occurrence of conodont Neostreptognathus pnevi-N. exculptus Leading candidate is Mechetlino in southern Ural Mtns.
GSSP anticipated in 2008
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base Artinskian Stage 284.4 0.7
"
Conodont -- lowest occurrence of conodont Sweetognathus whitei Leading candidate is Dalny-Tulkas sections in southern Ural Mtns.
GSSP anticipated in 2008
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base Sakmarian Stage 294.6 0.8
"
Conodont -- near lowest occurrence of conodont Sweetognathus merrelli Leading candidate is at Kondurovsky, Orenburg Province, Russia.
GSSP anticipated in 2008
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base Asselian Stage, base Cisuralian Series, base Permian System 299.0 0.8
"
Conodont -- lowest occurrence of Streptognathodus isolatus within the S. "wabaunsensis" conodont chronocline. 6 m higher is lowest fusilinid foraminifer Sphaeroschwagerina vulgaris aktjubensis 27 m above base of Bed 19, Aidaralash Creek, Aktöbe, southern Ural Mountains, northern Kazakhstan
(50°14'45"N*, 57°53'29"E*)
Ratified, 1996 Episodes 21 (1), p.11-18, 1998
Carboniferous System
Pennsylvanian Subsystem (series classification approved in 2004)
Upper Pennsylvanian Series
base Gzhelian Stage 303.4 0.9
"
Conodont -- lowest occurrence of Idiognathodus simulator (s.str.). Close to lowest occurrence of ammonoid Shumardites Candidates are in southern Urals or Nashui (south China) GSSP anticipated in 2008
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base Kasimovian Stage 307.2 1.0
"
Fusulinid (benthic foraminifer) -- lowest occurrence of fusulinid Protriticites, which is near lowest occurrence of ammonoid Eothalossoceras. Alternative (higher) base is lowest occurrence of fusulinid Montiparus montiparus, which is near lowest occurrence of conodont Idiognathodus sagittalis. Age given here is the higher version; the lower one is about 1 myr older. Candidates are in southern Urals, southwest USA and south-central China Guide event is undecided. GSSP anticipated in 2008
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Middle Pennsylvanian Series
base Moscovian Stage 311.7 1.1
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Conodont -- either the lowest occurrence of Idiognathoides postsulcatus or of Declinognathodus donetzianus Candidates are in southern Urals or Nashui (south China) Guide event is undecided. GSSP anticipated in 2009
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Lower Pennsylvanian Series
base Bashkirian Stage, base Pennsylvanian Subsystem 318.1 1.3
"
Conodont -- lowest occurrence of Declinognathodus nodiliferus s.l. 82.9 m above top of Battleship Wash Fm., Arrow Canyon, southern Nevada, USA
(36°44’00”N**, 114°46’40”W**)
GSSP ratified 1996. Subsystem rank with Mississippian and Pennsylvanian names ratified 2000. Episodes 22 (4), p.272-283, 1999
Mississippian Subsystem
Upper Mississippian Series (series classification approved in 2004)
base Serpukhovian 328.3 1.6
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Conodont -- lowest occurrence of Lochriea ziegleri [one zone lower than working definition in GTS04] Candidates are Verkhnyaya Kardailovka (southern Urals) or Nashui (south China) GSSP anticipated in 2008
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Middle Mississippian Series
base Visean 345.3 2.1
"
Benthic Foraminifer -- first appearance of Eoparastaffella simplex, in the lineage of “E. ovalis group” to E. simplex Base of Bed 83, stream section south of Pengchong village, 15 km N-NE of Liuzhou city, about 130 km SW of Guilin, Guangxi Autonomous Region (south China)
(24°26’N, 109°27’E)
ICS Voting in Feb, 2008
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Lower Mississippian Series
base Tournaisian, base Mississippian Subsystem, base Carboniferous System 359.2 2.5
"
Conodont -- was intended to be lowest occurrence of Siphonodella sulcata. IMPRECISE (GSSP discovered in 2006 to have biostrat problems, and can not be correlated wih precision.) Base of Bed 89, La Serre, Montagne Noire, Cabrières, southern France. [However, base of Bed 85 seems to have the FAD of S. sulcata.]
(43°33'19.9"N*, 3°21'26.3"E* )
Ratified 1990 Episodes 14 (4), p.331-336, 1991; Kölner Forum Geol. Paläont., 15, 2006
Devonian System
Upper Devonian Series
base Famennian Stage 374.5 2.6 Devonian time scale is a statistical fit of a composite biostratigraphic zonation (based on Figure 8 of Williams et al., 2000) to selected radiometric ages Conodont -- flood occurrence of Palmatolepis ultima and lowest occurrence of Pa. subperlobata. Just above major extinction horizon (top of Upper Kellwasser Event of widespread anoxia), including conodonts Ancyrodella and Ozarkodina and goniatites of Gephuroceratidae and Beloceratidae base of Bed 32a, upper Coumiac quarry, Cessenon, Montagne Noire, southern France
(43°27'40.6"N*, 3°02'25"E*)
Ratified 1993 Episodes 16 (4), p.433-441, 1993
base Frasnian Stage 385.3 2.6
"
Conodont -- lowest occurrence of Ancyrodella rotundiloba (early morphotype = r. pristina), defining the rotundiloba pristina or MN 1 Zone. Within polyphase time of major extinctions (Frasnes Events) Base of Bed 42a', Col du Puech de la Suque section, St. Nazaire-de-Ladarez, SE Montagne Noire, southern France
(43°30'11.4"N*, 3°05'12.6"E*)
Ratified 1986 Episodes 10 (2), p.97-101, 1987
Middle Devonian Series
base Givetian Stage 391.8 2.7
"
Conodont -- lowest occurrence of Polygnathus hemiansatus. Just above first entry of goniatite Maenioceratidae and above the Kacak Event of widespread anoxia Base of Bed 123, Jebel Mech Irdane ridge, Tafilalt, Morocco
(31°14'14.7"N*, 4°21'14.8"W*)
Ratified 1994 Episodes 18 (3), p.107-115, 1995
base Eifelian Stage 397.5 2.7
"
Conodont -- lowest occurrence of Polygnathus costatus partitus. Major faunal turnover slightly below the supposedly global Chotec Event of widespread anoxia Base unit WP30, trench at Wetteldorf Richtschnitt, Schönecken-Wetteldorf, Eifel Hills, western Germany
(50°08'58.6"N*, 6°28'17.6"E*)
Ratified 1985 Episodes 8 (2), p.104-109, 1985
Lower Devonian Series
base Emsian Stage 407.0 2.8
"
Conodont -- lowest occurrence of Polygnathus kitabicus (= Po. dehiscens). But this level lies well within the classical Pragian and a revision is in preparation Base of Bed 9/5, Zinzil'ban Gorge, SE of Samarkand, Uzbekistan
(39°12'N, 67°18'20"E)
Ratified 1995 Episodes 20 (4), p. 235-240, 1997
base Pragian Stage 411.2 2.8
"
Conodont -- lowest occurrence of Eognathodus sulcatus or, better, of Latericriodus steinachensis Morph beta Base of Bed 12, Valká Chuchle quarry, southwest part of Prague city, Czech Republic
(50°00'53"N*, 14°22'21.5"E*)
Ratified 1989 Episodes 12 (2), p.109-113, 1989
base Lochkovian Stage, base Devonian System 416.0 2.8 base-Devonian from scale in Cooper (GTS 2004), which is 1 myr younger than Tucker et al (1998) estimate. Graptolite -- lowest occurrence of Monograptus uniformis Within Bed 20, Klonk, Barrandian area, southwest of Prague, Czech Republic
(49.855°N**, 13.792°E**)
Ratified 1972 Martinsson (ed.), The Silurian-Devonian Boundary, IUGS Series A, no.5, 349 pp., 1977
Silurian System [Holland and Bassett (eds), A Global Standard for the Silurian System, Nat. Mus. Wales, Geol. Series No.10, Cardiff, 325 pp., 1989]
Pridoli Series
base Pridoli Series (not subdivided in stages) 418.7 2.7 Silurian and Ordovician time scales are from calibrating a CONOP composite graptolite zonation to selecte radiometric ages Graptolite, lowest occurrence of Monograptus parultimus Within Bed 96, Pozáry section near Reporje, Barrandian area, Prague, Czech Republic
(50°01'39.82"N*, 14°19'29.56"E*)
Ratified 1984 Episodes 8 (2), p.101-103, 1985
Ludlow Series
base Ludfordian Stage 421.3 2.6
"
Imprecise. May be near base of Saetograptus leintwardinensis graptolite zone. Base of lithological unit C, Sunnyhill Quarry, Ludlow, Shropshire, southwest England, UK
(52°20'55.06"N*, 2°46'38"W*)
Ratified 1980 Lethaia 14, p.168, 1981; Episodes 5 (3), p.21-23, 1982
base Gorstian Stage 422.9 2.5
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Imprecise. Just below base of local acritarch Leptobrachion longhopense range zone. May be near base of Neodiversograptus nilssoni graptolite zone Base of lithological unit F, Pitch Coppice quarry, Ludlow, Shropshire, southwest England, UK
(52°21'33"N*, 2°46'38"W*)
Ratified 1980 Lethaia 14, p.168, 1981; Episodes 5 (3), p.21-23, 1982
Wenlock Series
base Homerian Stage 426.2 2.4
"
Graptolite, lowest occurrence of Cyrtograptus lundgreni (defines base of C. lundgreni graptolite zone) Graptolite biozone intersection in stream section in Whitwell Coppice, Homer, Shropshire, southwest England, UK
(52°36'56"N*, 2°33'53"W*)
Ratified 1980 Lethaia 14, p.168, 1981; Episodes 5 (3), p.21-23, 1982
base Sheinwoodian Stage 428.2 2.3
"
Imprecise. Between the base of acritarch biozone 5 and extinction of conodont Pterospathodus amorphognathoides. However, the current GSSP does not coincide with the base of the Cyrtograptus centrifugus Biozone, as was supposed when the GSSP was defined. Restudy has recommended a slightly higher and correlatable level on condonts -- the Ireviken datum 2, which coincides approximately with the base of the murchisoni graptolite biozone Base of lithological unit G, Hughley Brook, Apedale, Shropshire, southwest England, UK
(52°34'52"N*, 2°38"20"W*)
Ratified 1980 Lethaia 14, p.168, 1981; Episodes 5 (3), p.21-23, 1982
Llandovery Series
base Telychian Stage 436.0 1.9
"
Brachiopods, just above extinction of Eocoelia intermedia and below lowest succeeding species Eocoelia curtisi. Near base of Monograptus turriculatus graptolite zone. Locality 162 in transect d, Cefn Cerig road, Llandovery area, south-central Wales, UK
(51.97°N**, 3.79°W**)
Ratified 1984 Episodes 8 (2), p.101-103, 1985
base Aeronian Stage 439.0 1.8
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Graptolite, lowest occurrence of Monograptus austerus sequens (defines base of Monograptus triangulatus graptolite zone) Base of locality 72 in transect h, Trefawr forestry road, north of Cwm-coed-Aeron Farm, Llandovery area, south-central Wales, UK
(52.03°N**, 3.70°W**)
Ratified 1984 Episodes 8 (2), p.101-103, 1985
base Rhuddanian Stage, base Silurian System 443.7 1.5
"
Graptolites, lowest occurrences of Akidograptus ascensus, with FAD of Parakidograptus acuminatus occurring slightly higher 1.6 m above base of Birkhill Shale Fm., Dob's Linn, Moffat, Scotland, UK
(55.44°N**, 3.27°W**)
Ratified 1984 Episodes 8 (2), p.101-103, 1985
Ordovician System
Upper Ordovician Series
base Hirnantian Stage 445.6 1.5
"
Graptolite, lowest occurrence of Normalograptus extraordinarius, base of major positive carbon-13 isotope excursion, and beginning of pronounced sea-level fall associated with onset of a major glaciation 0.39 m below base of Kuanyinchiao Bed, Wangjiawan North section, 42 km N. of Yichang city (west Hubei province, China)
(30°59'2.68"N, 111°25'10.76"E)
Ratified 2006 Episodes 29 (3), p.183-196, 2006
base Katian Stage 455.8 1.6
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Graptolite, lowest occurrence of Diplacanthograptus caudatus. Just below base of Guttenberg carbon-13 isotope excursion 4 m above base of Bigfort Chert, Black Knob Ridge section, 5 km NE of Atoka town (S. Oklahoma, USA)
(34°25.829'N, 96°4.473'W)
Ratified 2006
Episodes 30 (4), 2007
base Sandbian Stage 460.9 1.6
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Graptolite, lowest occurrence of Nemagraptus gracilis 1.4 m below phosphorite in E14a outcrop, Fågelsång, Scane, southern Sweden
(55°42'49.3"N*, 13°19'31.8"E*)
Ratified 2002 Episodes 23 (2), p.102-109, 2000
Middle Ordovician Series
base Darriwilian Stage 468.1 1.6
"
Graptolite, lowest occurrence of Undulograptus austrodentatus Base of Bed AEP184, 22 m below top of Ningkuo Fm., Huangnitang, Changshan, Zhejiang province, southeast China
(28°51'14"N*, 118°29'23"E*)
Ratified 1987 Episodes 20 (3), p.158-166, 1997
base of Dapingian Stage 471.8 1.6
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Conodont -- lowest occurrence of Baltoniodus triangularis. Approximates the boundary between the lower and upper intervals of Azygograptus suecicus graptolite zone 10.57 m above the base of the Dawan Formation (base of Bed SHod-16), Huanghuachang roadside exposure, 22km NE of the Yichang city (Hubei Province, South China)
(30°51’37.8’’N, 110°22’26.5’’E)
Ratified 2007 Proposal in Episodes 28 (2), p.105-117, 2005
Lower Ordovician Series
Base Floian Stage 478.6 1.7
"
Graptolite, lowest occurrence of Tetragraptus approximatus in the lower Tøyen Shale, 2.1m above the top of the Cambrian. Diabasbrottet quarry, 5 km NW of Flo village, Västergötland, southern Sweden
(58°21'32.2"N, 12°30'08.6"E)
Ratified 2002 Episodes 27 (4), p.265-272, 2004
base of Tremadocian stage, base Ordovician System 488.3 1.7
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Conodont, lowest occurrence of Iapetognathus fluctivagus;just above base of Cordylodus lindstromi conodont Zone. Just below lowest occurrence of planktonic graptolites Within Bed 23 at the 101.8 m level, Green Point, western Newfoundland, Canada
(49°40'58.5"N*, 57°57'55.09"W*)
Ratified 2000 Episodes 24 (1), p.19-28, 2001
Cambrian System
Overview of potential Cambrian subdivisions in Episodes 23 (3), p. 188-195, 2000
Furongian Series
Stage 10 492.0 - Estimaged from trilobite-zone scalings Trilobite -- lowest occurrence of Lotagnostus americanus. An internal substage division might be lowest occurrence of Codylodus adesei conodont
Candidate section is Duibian (Zhejiang province, China)
GSSP anticipated in 2009
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Stage 9 496.0 - Estimaged from trilobite-zone scalings Trilobite -- lowest occurrence of Agnostotes orientalis
Candidate sections at Duibian (Zhejiang province, China) and Gonggiri (Korea)
GSSP anticipated in 2008
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base Paibian Stage, base Furongian Series 499.0 2.0 Radiometric ages near primary marker level. Estimated age and uncertainty only Trilobite, lowest occurrence of agnostoid Glyptagnostus reticulatus. Coincides with base of large positive carbon-isotope excursion 369.06 m above base of Huaqiao Fm, Paibi section, NW Hunan province, south China
(28°23.37'N, 109°31.54'E)
Ratified 2003 Lethaia 37 (4), p.365-380, 2004
Series 3
Base Guzhangian Stage 503.0 - Estimaged from trilobite-zone scalings Trilobite -- lowest occurrence of Lejopyge laevigata >121.3 m above the base of the Huaqiao Formation. Louyixi, Guzhang County, NW Hunan Province, S. China
(28°43.20'N, 109°57.88'E)
GSSP anticipated in 2009
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Base Drumian Stage 506.5 - Estimaged from trilobite-zone scalings Trilobite -- lowest occurrence of Ptychagnostus atavus. Just above the GSSP is a significant negative carbon-isotope excursion 62 m above base of Wheeler Fm., Stratotype Ridge, Drum Mountains, western Utah, USA
(39°30.705'N, 112°59.489'W)
Ratified 2006 Episodes 30 (2), 2007
Stage 5 510.0 - Estimaged from trilobite-zone scalings -- slightly younger than the 511 Ma age on Protolenus and Ellipsocephalus-bearing strata in New Brunswick Trilobite -- potentially lowest occurrence of Oryctocephalus indicus Candidate sections are Wuliu-Zengjiayan (east Guizhou, China) and Split Mountain (Nevada, USA) GSSP anticipated in 2008
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Series 2
Stage 4 517.0 -
-
Trilobite -- lowest occurrence of Olenellus or Redlichia
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GSSP anticipated in 2009
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Stage 3 521.0 -
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Trilobites -- their lowest occurrence (superfamily Fallotaspidoidae)
-
GSSP anticipated in 2009
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Terreneuvian Series
Stage 2 528.0 - Estimated (S. Peng, Nov'07) Potentially the lowest Small Shelly Fossil, which is earlier than the lowest Archaeocyathans
-
Guide event is undecided
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Base of Fortunian Stage, base of Terreneuvian Series, base Cambrian System, base Paleozoic Era, base Phanerozoic Eon 542.0 1.0 U-Pb age from Oman coinciding with the negative carbon excursion Trace fossil -- lowest occurrence of Treptichnus (Phycodes) pedum. Near base of negative carbon-isotope excursion 2.4 m above base of Member 2 of Chapel Island Fm., Fortune Head, Burin Peninsula, southeast Newfoundland, Canada
(47°4'34.47"N*, 55°49'51.71"W*)
Ratified 1992 Episodes 17 (1&2), p.95-100, 1994
PROTEROZOIC Eon
Pre-Cambrian eras and systems below Ediacaran are defined by absolute ages, rather than stratigraphic points.
Neoproterozoic Era
base Ediacaran System 635
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Age suggested by Ediacaran Subcomm.; bracketed by radiometric ages of 600 and 635 Ma Climatic and Geochemical -- Termination of Marinoan (or Varanger) glaciation, and distinctive C-13 change Base of the Marinoan cap carbonate (Nuccaleena Formation), immediately above the Elatina diamictite in the Enorama Creek section, Flinders Ranges, South Australia
(31°19'53.2"S, 138°38'0.2"E)
"Neoproterozoic III" (ratified 1990 with base defined chronometrically at 650 Ma) was formally replaced by Ediacaran Period and its GSSP in Feb 2004. Summary in Science 305, p.621-622, 2004. Episodes article in preparation
Cryogenian Period 850
-
Defined chronometrically; but will be replaced by GSSP. First glacial episode occurred after 750 Ma Base = 850 Ma
-
Ratified 1990. GSSP replacement planned for 2009 Episodes 14 (2), p.139-140, 1991
Tonian Period 1000
-
Defined chronometrically Base = 1000 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Mesoproterozoic Era
Stenian Period 1200
-
Defined chronometrically Base = 1200 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Ectasian Period 1400
-
Defined chronometrically Base = 1400 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Calymmian Period 1600
-
Defined chronometrically Base = 1600 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Paleoproterozoic Era
Statherian Period 1800
-
Defined chronometrically Base = 1800 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Orosirian Period 2050
-
Defined chronometrically Base = 2050 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Rhyacian Period 2300
-
Defined chronometrically Base = 2300 Ma
-
Ratified 1990 Episodes 14 (2), p.139-140, 1991
Siderian Period 2500
-
Defined chronometrically; but will be replaced by GSSP Base = 2500 Ma
-
Ratified 1990. GSSP replacement planned for 2009 Episodes 14 (2), p.139-140, 1991
ARCHEAN Eon
Neoarchean Era
(no subdivision)
2800
-
Defined chronometrically Base = 2800 Ma
-
Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15 (2), p.122-123, 1992
Mesoarchean Era
(no subdivision)
3200
-
Defined chronometrically Base = 3200 Ma
-
Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15 (2), p.122-123, 1992
Paleoarchean Era
(no subdivision)
3600
-
Defined chronometrically Base = 3600 Ma
-
Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15 (2), p.122-123, 1992
Eoarchean Era
(no subdivision)
~4000
-
Base is not defined Oldest preserved rocks on Earth's surface
-
Subcomm. decision 1996, but not submitted to ICS Informally in Episodes 15 (2), p.122-123, 1992
HADEAN Eon ~4600
-
Base is not defined Formation of planet Earth. Informal term
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-
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* according to Google Earth
** derived from maps