GSSP

A GSSP, more fully a Global Boundary Stratotype Section and Point, is an internationally agreed point which defines the start of a stage on the geologic time scale.

The work is done by the International Commission on Stratigraphy, a part of the International Union of Geological Sciences. As of 2012, 64 of the 101 stages that need a GSSP have been decided.

Rules for GSSP

A geologic section has to follow the rules to be adapted as a GSSP by the ICS. The list below are the rules:

A GSSP has to decide the lower boundary (start of a geological period) of a geologic stage.
The lower boundary (start of a geological period) has to be decided using a primary (main) marker (usually first appearance datum of a fossil specie).
- There should also be secondary markers (other fossils, chemical, geomagnetic reversal).
- The horizon in which the marker appears should have minerals that can be radiometrically dated.
- The marker has to have regional and global correlation in outcrops of the same age
- The marker should be independent of facies.
The outcrop has to have an acceptable thickness
Sedimentation has to be constant without any changes in facies
The outcrop should not be affected by tectonic and sedimentary movements, and metamorphism
The outcrop has to be accessible to research and free to access.
- This includes that the outcrop has to be located where it can be visited quickly (International airport and good roads), has to be kept in good condition (Ideally a national reserve), in accessible terrain, extensive enough to allow repeated sampling and open to researchers of all nationalities.

List

This list shows some of the GSSPs.

Period	Epoch	Age (mya)	GSSP location	Defining markers	Geographic Coordinates
Phanerozoic
Cainozoic
Quaternary
	Holocene	0.117	NGRIP2 ice core, Greenland	End of the Younger Dryas stadial (cold stage)	75°06′00″N 42°19′12″W / 75.1000°N 42.3200°W / 75.1000; -42.3200
	Pleistocene	2.588	Monte San Nicola Section, Sicily, Italy	Base of magnetic polarity chronozone C2r (Matuyama). Extinction of Discoaster pentaradiatus and Discoaster surculus (Calcareous nannofossil).	37°08′49″N 14°12′13″E / 37.1469°N 14.2035°E / 37.1469; 14.2035
Neogene
	Pliocene	5.333	Heraclea Minoa section Heraclea Minoa, Sicily, Italy	Top of magnetic polarity chronozone C3r. First appearance of Ceratolithus acutus and near extinction of Triquetrorhabdulus rugosus (Calcareous nannofossil).	37°23′30″N 13°16′50″E / 37.3917°N 13.2806°E / 37.3917; 13.2806
	Miocene	23.03	Lemme-Carrosio Section, Carrosio, Italy	Base of magnetic polarity chronozone C6Cn.2n. Near first appearance of Paragloborotalia kugleri (Planktonic foraminifera).	44°39′32″N 8°50′11″E / 44.6589°N 8.8364°E / 44.6589; 8.8364
Palaeogene
	Oligocene	33.9	Massignano Section, Massignano, Ancona, Italy	Extinction of Hantkenina and Cribrohantkenina (Planktonic foraminifera).	43°31′58″N 13°36′04″E / 43.5328°N 13.6011°E / 43.5328; 13.6011
	Eocene	56	Dababiya section, Luxor, Egypt	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
	Palaeocene	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
	Upper Cretaceous	100.5	Mont Risoux, Hautes-Alpes, France	First appearance of Rotalipora globotruncanoides (Planktonic foraminifera)	44°23′33″N 5°30′43″E / 44.3925°N 5.5119°E / 44.3925; 5.5119
	Lower Cretaceous	145		Candidates: Magnetic—base of Chron M18r Base of Calpionellid zone B
Jurassic
	Upper Jurassic	163.5	Candidate sections: Redcliff Point, Dorset, England Savouron, Provence, France	Horizon of Cardioceras redcliffense (Ammonite).
	Middle Jurassic	174.1	Fuentelsaz, Spain	First appearance of Leioceras opalinum and Leioceras lineatum Biologic: First appearance of genus Leioceras (Ammonite).	41°10′15″N 1°50′00″W / 41.1708°N 1.8333°W / 41.1708; -1.8333
	Lower Jurassic	201.3	Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria	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
	Upper Triassic	235	Prati di Stuores, Dolomites, Italy	First appearance of Daxatina canadensis (Ammonite). Near first appearance of Metapolygnathus polygnathiformis (Conodont). Above magnetic zone S2n.	46°31′37″N 11°55′49″E / 46.5269°N 11.9303°E / 46.5269; 11.9303
	Middle Triassic	247.2	Candidate sections: Desli Caira, Dobrogea, Romania Guandao, Guizhou, China	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 Triassic	252.2	Meishan, Zhejiang, China	First appearance of Hindeodus parvus (Conodont).	31°04′47″N 119°42′21″E / 31.0798°N 119.7058°E / 31.0798; 119.7058
Palaeozoic
Permian		298.9	Aidaralash, Ural Mountains, Kazakhstan	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
	Pennsylvanian	323.2	Arrow Canyon, Nevada, USA	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	358.9	La Serre, Montagne Noire, France	First appearance of Siphonodella sulcata (Conodont). In 2006 it was discovered that this GSSP has biostratigraphic problems.	43°33′20″N 3°21′26″E / 43.5555°N 3.3573°E / 43.5555; 3.3573
Devonian		419.2	Klonk, Prague, Czech Republic	First appearance of Monograptus uniformis (graptolite).	49°51′18″N 13°47′31″E / 49.8550°N 13.7920°E / 49.8550; 13.7920
Silurian		443.4	Dob's Linn, Moffat, U.K.	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		485.4	Greenpoint section Green Point, Newfoundland, Canada	First appearance of Iapetognathus fluctivagus (Conodont). Planktonic graptolites occur 4.8 m above boundary. 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		541	Fortune head section, Newfoundland, Canada	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
Era	Period	Precambrian
Proterozoic
Neoproterozoic
	Ediacaran	635	Enorama Creek section Flinders Ranges, South Australia	Worldwide distinct cap carbonates. 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
	Cryogenian	850	Defined chronometrically now. GSSP is in progress.
	Tonian	1000	Defined chronometrically
Mesoproterozoic
	Stenian	1200	Defined chronometrically
	Ectasian	1400	Defined chronometrically
	Calymmian	1600	Defined chronometrically
Palaeoproterozoic
	Statherian	1800	Defined chronometrically
	Orosirian	2050	Defined chronometrically
	Rhyacian	2300	Defined chronometrically
	Siderian	2500	Defined chronometrically
Archaean & Hadean
Neoarchaean		2800
Mesoarchaean		3200
Palaeoarchaean		3600
Eoarchaean		4000
Hadean		4567

Global Standard Stratigraphic Age (GSSAs)

Because defining a GSSP depends on finding well-preserved geologic sections and identifying key events, this task becomes more harder as one goes farther back in time. Before 640 million years ago, boundaries on the geologic timescale are defined simply by reference to fixed dates, known as "Global Standard Stratigraphic Ages". The oldest GSSP is the one that marks the start of the Ediacaran at 635 million years ago.

References

↑ "International Chronostratigraphic Chart 2012" (PDF). ICS. Retrieved 28 November 2012.
↑ Remane J. et al 1996. "Guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy (ICS)". Episodes. 19: 77–81. doi:10.18814/epiiugs/1996/v19i3/007.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ "GSSP Rules". Geologic Timescale Foundation.
↑ Walker, Mike et al 2009 (2009). "Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core, and selected auxiliary records". Journal of Quaternary Science. 24 (1): 3–17. Bibcode:2009JQS....24....3W. doi:10.1002/jqs.1227. S2CID 40380068.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Rio, Domenico et al 1998 (1998). "The Gelasian Stage (Upper Pliocene): a new unit of the global standard chronostratigraphic scale". Episodes. 21 (2): 82–87. Bibcode:1998Episo..21...82R. doi:10.18814/epiiugs/1998/v21i2/002.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Couvering John A. Van et al 2000 (2000). "The base of the Zanclean Stage and of the Pliocene Series". Episodes. 23 (3): 179–187. doi:10.18814/epiiugs/2000/v23i3/005. S2CID 10836910.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Steininger, Fritz F. et al 1997 (1997). "The Global Stratotype Section and Point (GSSP) for the base of the Neogene". Episodes. 20 (1): 23–28. Bibcode:1997Episo..20...23S. doi:10.18814/epiiugs/1997/v20i1/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Silva, Isabella Premoli; Jenkins, D Graham (1993). "Decision on the Eocene-Oligocene boundary stratotype". Episodes. 16 (3): 379–382. Bibcode:1993Episo..16..379S. doi:10.18814/epiiugs/1993/v16i3/002.
↑ Dupuis C. et al 2003 (2003). "The Dababiya Quarry section: lithostratigraphy, clay mineralogy, geochemistry and paleontology". Micropaleontology. 49 (1): 41–59. Bibcode:2003MiPal..49S..41D. doi:10.2113/49.Suppl_1.41. hdl:1912/5251.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Aubry, Marie-Pierre et al 2007 (2007). "The Global Standard Stratotype-section and Point (GSSP) for the base of the Eocene Series in the Dababiya section (Egypt)". Episodes. 30 (4): 271–286. doi:10.18814/epiiugs/2007/v30i4/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Molina, Eustoquio 2006; et al. (2006). "The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, "Tertiary", Cenozoic) at El Kef, Tunisia - Original definition and revision". Episodes. 29 (4): 263–278. doi:10.18814/epiiugs/2006/v29i4/004.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Kennedy, W.J.; Gale, A.S.; Lees, J.A.; Caron, M. (2004). "The Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France". Episodes. 27 (1): 21–32. doi:10.18814/epiiugs/2004/v27i1/003.
↑ Cresta S. et al 2001 (2001). "The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)". Episodes. 24 (3): 166–175. Bibcode:2001Episo..24..166C. doi:10.18814/epiiugs/2001/v24i3/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Mietto P. et al 2012 (2012). "The Global Boundary Stratotype Section and Point (GSSP) of the Carnian stage (Late Triassic) at Prati di Stuores/Stuores Wiesen section (Southern Alps, NE Italy)". Episodes. 35 (3): 414–430. Bibcode:2012Episo..35..414M. doi:10.18814/epiiugs/2012/v35i3/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Davydov, Vladimir I. et al 1998 (1998). "Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System". Episodes. 21 (1): 11–18. Bibcode:1998Episo..21...11D. doi:10.18814/epiiugs/1998/v21i1/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Lane, H. Richard et al 1999. (1999). "The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA". Episodes. 22 (4): 272–283. doi:10.18814/epiiugs/1999/v22i4/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Paproth, Eva et al 1991 (1991). "Decision on the Devonian - Carboniferous boundary stratotype". Episodes. 14 (4): 331–336. doi:10.18814/epiiugs/1991/v14i4/004.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 14 September 2012.}
↑ Holland C.H. 1985 (1985). "Series and Stages of the Silurian System". Episodes. 8 (2): 101–103. Bibcode:1985Episo...8..101H. doi:10.18814/epiiugs/1985/v8i2/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Cooper R.A. et al 2001 (2001). "Global Stratotype Section and Point for base of the Ordovician System". Episodes. 24 (1): 19–28. doi:10.18814/epiiugs/2001/v24i1/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)
↑ Brasier, Martin; Cowie, John; Taylor, Michael (1994). "Decision on the Precambrian-Cambrian boundary stratotype". Episodes. 17 (1–2): 3–8. doi:10.18814/epiiugs/1994/v17i1.2/002.
↑ Knoll, Andrew et al 2006 (2006). "The Ediacaran Period: a new addition to the geologic time scale". Lethaia. 39 (1): 13–30. Bibcode:2006Letha..39...13K. doi:10.1080/00241160500409223.{{cite journal}}: CS1 maint: numeric names: authors list (link)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 Plumb, K. A. (1991). "New Precambrian timescale". Episodes. 14 (2): 139–140. doi:10.18814/epiiugs/1991/v14i2/005.

[International_Chronostratigraphic_Chart_2012-1] "International Chronostratigraphic Chart 2012" (PDF). ICS. Retrieved 28 November 2012.

[Remane_1996-2] Remane J. et al 1996. "Guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy (ICS)". Episodes. 19: 77–81. doi:10.18814/epiiugs/1996/v19i3/007.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[GSSP_Rules-3] "GSSP Rules". Geologic Timescale Foundation.

[Walker_2009-4] Walker, Mike et al 2009 (2009). "Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core, and selected auxiliary records". Journal of Quaternary Science. 24 (1): 3–17. Bibcode:2009JQS....24....3W. doi:10.1002/jqs.1227. S2CID 40380068.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Rio_1998-5] Rio, Domenico et al 1998 (1998). "The Gelasian Stage (Upper Pliocene): a new unit of the global standard chronostratigraphic scale". Episodes. 21 (2): 82–87. Bibcode:1998Episo..21...82R. doi:10.18814/epiiugs/1998/v21i2/002.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Couvering_2000-6] Couvering John A. Van et al 2000 (2000). "The base of the Zanclean Stage and of the Pliocene Series". Episodes. 23 (3): 179–187. doi:10.18814/epiiugs/2000/v23i3/005. S2CID 10836910.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Steininger_1997-7] Steininger, Fritz F. et al 1997 (1997). "The Global Stratotype Section and Point (GSSP) for the base of the Neogene". Episodes. 20 (1): 23–28. Bibcode:1997Episo..20...23S. doi:10.18814/epiiugs/1997/v20i1/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Silva_1993-8] Silva, Isabella Premoli; Jenkins, D Graham (1993). "Decision on the Eocene-Oligocene boundary stratotype". Episodes. 16 (3): 379–382. Bibcode:1993Episo..16..379S. doi:10.18814/epiiugs/1993/v16i3/002.

[Dupuis_2003-9] Dupuis C. et al 2003 (2003). "The Dababiya Quarry section: lithostratigraphy, clay mineralogy, geochemistry and paleontology". Micropaleontology. 49 (1): 41–59. Bibcode:2003MiPal..49S..41D. doi:10.2113/49.Suppl_1.41. hdl:1912/5251.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Aubry_2007-10] Aubry, Marie-Pierre et al 2007 (2007). "The Global Standard Stratotype-section and Point (GSSP) for the base of the Eocene Series in the Dababiya section (Egypt)". Episodes. 30 (4): 271–286. doi:10.18814/epiiugs/2007/v30i4/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Molina_2006-11] Molina, Eustoquio 2006; et al. (2006). "The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, "Tertiary", Cenozoic) at El Kef, Tunisia - Original definition and revision". Episodes. 29 (4): 263–278. doi:10.18814/epiiugs/2006/v29i4/004.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Kennedy_2004-12] Kennedy, W.J.; Gale, A.S.; Lees, J.A.; Caron, M. (2004). "The Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France". Episodes. 27 (1): 21–32. doi:10.18814/epiiugs/2004/v27i1/003.

[Cresta_2001-13] Cresta S. et al 2001 (2001). "The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)". Episodes. 24 (3): 166–175. Bibcode:2001Episo..24..166C. doi:10.18814/epiiugs/2001/v24i3/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Mietto_2007-14] Mietto P. et al 2012 (2012). "The Global Boundary Stratotype Section and Point (GSSP) of the Carnian stage (Late Triassic) at Prati di Stuores/Stuores Wiesen section (Southern Alps, NE Italy)". Episodes. 35 (3): 414–430. Bibcode:2012Episo..35..414M. doi:10.18814/epiiugs/2012/v35i3/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Davydov_1998-15] Davydov, Vladimir I. et al 1998 (1998). "Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System". Episodes. 21 (1): 11–18. Bibcode:1998Episo..21...11D. doi:10.18814/epiiugs/1998/v21i1/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Lane_1999-16] Lane, H. Richard et al 1999. (1999). "The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA". Episodes. 22 (4): 272–283. doi:10.18814/epiiugs/1999/v22i4/003.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Paproth_1991-17] Paproth, Eva et al 1991 (1991). "Decision on the Devonian - Carboniferous boundary stratotype". Episodes. 14 (4): 331–336. doi:10.18814/epiiugs/1991/v14i4/004.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[GSSP_Web-18] "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 14 September 2012.}

[Holland_1985-19] Holland C.H. 1985 (1985). "Series and Stages of the Silurian System". Episodes. 8 (2): 101–103. Bibcode:1985Episo...8..101H. doi:10.18814/epiiugs/1985/v8i2/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Cooper_2001-20] Cooper R.A. et al 2001 (2001). "Global Stratotype Section and Point for base of the Ordovician System". Episodes. 24 (1): 19–28. doi:10.18814/epiiugs/2001/v24i1/005.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Brasier_1994-21] Brasier, Martin; Cowie, John; Taylor, Michael (1994). "Decision on the Precambrian-Cambrian boundary stratotype". Episodes. 17 (1–2): 3–8. doi:10.18814/epiiugs/1994/v17i1.2/002.

[Knoll_2006-22] Knoll, Andrew et al 2006 (2006). "The Ediacaran Period: a new addition to the geologic time scale". Lethaia. 39 (1): 13–30. Bibcode:2006Letha..39...13K. doi:10.1080/00241160500409223.{{cite journal}}: CS1 maint: numeric names: authors list (link)

[Plumb_1991-23] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Plumb, K. A. (1991). "New Precambrian timescale". Episodes. 14 (2): 139–140. doi:10.18814/epiiugs/1991/v14i2/005.