GSSP

boundary of a stage on the geologic time scale

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.

Many GSSPs are marked by golden spikes. This 'golden spike' marks the GSSP for the start of the Ediacaran.

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.[1]

Rules for GSSPEdit

A geologic section has to follow the rules to be adapted as a GSSP by the ICS. The list below are the rules:[2][3]

  • 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.

ListEdit

This list shows some of the GSSPs.

Period Epoch Age (mya) Status GSSP location Defining markers Geographic Coordinates References
Phanerozoic
Cainozoic
Quaternary
Holocene 0.117 NGRIP2 ice core,

Greenland

75°06′00″N 42°19′12″W / 75.1000°N 42.3200°W / 75.1000; -42.3200 [4]
Pleistocene 2.588 Monte San Nicola Section,

Sicily, Italy

37°08′49″N 14°12′13″E / 37.1469°N 14.2035°E / 37.1469; 14.2035 [5]
Neogene
Pliocene 5.333 Heraclea Minoa section

Heraclea Minoa, Sicily, Italy

37°23′30″N 13°16′50″E / 37.3917°N 13.2806°E / 37.3917; 13.2806 [6]
Miocene 23.03 Lemme-Carrosio Section,

Carrosio, Italy

44°39′32″N 8°50′11″E / 44.6589°N 8.8364°E / 44.6589; 8.8364 [7]
Palaeogene
Oligocene 33.9 Massignano Section,

Massignano, Ancona, Italy

43°31′58″N 13°36′04″E / 43.5328°N 13.6011°E / 43.5328; 13.6011 [8]
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 [9][10]
Palaeocene 66 El Kef Section,

El Kef, Tunisia

36°09′13″N 8°38′55″E / 36.1537°N 8.6486°E / 36.1537; 8.6486 [11]
Mesozoic
Cretaceous
Upper Cretaceous 100.5 Mont Risoux,

Hautes-Alpes, France

44°23′33″N 5°30′43″E / 44.3925°N 5.5119°E / 44.3925; 5.5119 [12]
Lower Cretaceous 145

Candidates:

  • Magnetic—base of Chron M18r
Jurassic
Upper Jurassic 163.5 Candidate sections:
Middle Jurassic 174.1 Fuentelsaz, Spain 41°10′15″N 1°50′00″W / 41.1708°N 1.8333°W / 41.1708; -1.8333 [13]
Lower Jurassic 201.3 Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria 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 46°31′37″N 11°55′49″E / 46.5269°N 11.9303°E / 46.5269; 11.9303 [14]
Middle Triassic 247.2 Candidate sections: 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 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 50°14′45″N 57°53′29″E / 50.2458°N 57.8914°E / 50.2458; 57.8914 [15]
Carboniferous
Pennsylvanian 323.2 Arrow Canyon, Nevada, USA 36°44′00″N 114°46′40″W / 36.7333°N 114.7778°W / 36.7333; -114.7778 [16]
Mississippian 358.9 La Serre, Montagne Noire, France 43°33′20″N 3°21′26″E / 43.5555°N 3.3573°E / 43.5555; 3.3573 [17]
Devonian 419.2 Klonk, Prague, Czech Republic 49°51′18″N 13°47′31″E / 49.8550°N 13.7920°E / 49.8550; 13.7920 [18]
Silurian 443.4 Dob's Linn, Moffat, U.K. 55°26′24″N 3°16′12″W / 55.4400°N 3.2700°W / 55.4400; -3.2700 [19]
Ordovician 485.4 Greenpoint section

Green Point, Newfoundland, Canada

49°40′58″N 57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653 [20]
Cambrian 541 Fortune head section,

Newfoundland, Canada

47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W / 47.0762; -55.8310 [21]
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 [22]
Cryogenian 850 Defined chronometrically now. GSSP is in progress. [23]
Tonian 1000 Defined chronometrically [23]
Mesoproterozoic
Stenian 1200 Defined chronometrically [23]
Ectasian 1400 Defined chronometrically [23]
Calymmian 1600 Defined chronometrically [23]
Palaeoproterozoic
Statherian 1800 Defined chronometrically [23]
Orosirian 2050 Defined chronometrically [23]
Rhyacian 2300 Defined chronometrically [23]
Siderian 2500 Defined chronometrically [23]
Archaean & Hadean
Neoarchaean 2800 [23]
Mesoarchaean 3200 [23]
Palaeoarchaean 3600 [23]
Eoarchaean 4000 [23]
Hadean 4567 [23]

Global Standard Stratigraphic Age (GSSAs)Edit

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.

ReferencesEdit

  1. "International Chronostratigraphic Chart 2012". ICS. Retrieved 28 November 2012.
  2. Remane J. et al 1996. "Guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy (ICS)" (PDF). Episodes. 19: 77–81. Archived from the original (PDF) on 2014-12-28. Retrieved 2013-06-11.
  3. "GSSP Rules". Geologic Timescale Foundation. Retrieved 28 November 2012.
  4. Walker, Mike et al 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. doi:10.1002/jqs.1227.
  5. Rio, Domenico et al 1998. "The Gelasian Stage (Upper Pliocene): a new unit of the global standard chronostratigraphic scale" (PDF). Episodes. 21 (2): 82–87. Retrieved 14 September 2012.
  6. Couvering John A. Van et al 2000. "The base of the Zanclean Stage and of the Pliocene Series" (PDF). Episodes. 23 (3): 179. Retrieved 14 September 2012.
  7. Steininger, Fritz F. et al 1997. "The Global Stratotype Section and Point (GSSP) for the base of the Neogene" (PDF). Episodes. 20 (1): 23–28. Retrieved 14 September 2012.
  8. Silva, Isabella Premoli (1993). "Decision on the Eocene-Oligocene boundary stratotype" (PDF). Episodes. 16 (3): 379–382. Retrieved 14 September 2012. Unknown parameter |coauthors= ignored (|author= suggested) (help)
  9. Dupuis C. et al 2003 (2003). "The Dababiya Quarry section: lithostratigraphy, clay mineralogy, geochemistry and paleontology" (PDF). Micropaleontology. 49 (1): 41–59. Retrieved 14 September 2012.
  10. Aubry, Marie-Pierre et al 2007. "The Global Standard Stratotype-section and Point (GSSP) for the base of the Eocene Series in the Dababiya section (Egypt)" (PDF). Episodes. 30 (4): 271–286. Retrieved 14 September 2012.
  11. Molina, Eustoquio 2006; et al. "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" (PDF). Episodes. 29 (4): 263–278. Retrieved 14 September 2012.
  12. Kennedy, W. J. (2004). "The Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France" (PDF). Episodes. 27 (1): 21–32. Retrieved 16 September 2012. Unknown parameter |coauthors= ignored (|author= suggested) (help)
  13. Cresta S. et al 2001. "The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)" (PDF). Episodes. 24 (3): 166–175. Retrieved 17 September 2012.
  14. Mietto P. et al 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)" (PDF). Episodes. 35: 414–430. Retrieved 4 February 2013.
  15. Davydov, Vladimir I. et al 1998. "Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System" (PDF). Episodes. 21 (1): 11–18. Retrieved 18 September 2012.
  16. Lane, H. Richard et al 1999. "The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA" (PDF). Episodes. 22 (4): 272–283. Retrieved 18 September 2012.
  17. Paproth, Eva et al 1991. "Decision on the Devonian - Carboniferous boundary stratotype" (PDF). Episodes. 14 (4): 331–336. Retrieved 18 September 2012.
  18. "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 14 September 2012.
  19. Holland C.H. 1985. "Series and Stages of the Silurian System" (PDF). Episodes. 8 (2): 101–103. Retrieved 19 September 2012.
  20. Cooper R.A. et al 2001. "Global Stratotype Section and Point for base of the Ordovician System" (PDF). Episodes. 24 (1): 19–28. Retrieved 20 September 2012.
  21. Brasier, Martin et al 1994. "Decision on the Precambrian-Cambrian boundary stratotype" (PDF). Episodes. 17 (1–2): 95–100. Retrieved 14 September 2012.
  22. Knoll, Andrew et al 2006. "The Ediacaran Period: a new addition to the geologic time scale" (PDF). Lethaia. 39 (1): 13–30. doi:10.1080/00241160500409223. Retrieved 14 September 2012.
  23. 23.00 23.01 23.02 23.03 23.04 23.05 23.06 23.07 23.08 23.09 23.10 23.11 23.12 23.13 Plumb, K. A. (1991). "New Precambrian timescale" (PDF). Episodes. 14 (2). Retrieved 14 September 2012.