Rules for GSSP[change | change source]
- 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[change | change source]
This list shows some of the GSSPs.
|Period||Epoch||Age (mya)||Status||GSSP location||Defining markers||Geographic Coordinates||References|
|Holocene||0.117||NGRIP2 ice core,|||
|Pleistocene||2.588||Monte San Nicola Section,|||
|Pliocene||5.333||Heraclea Minoa section|||
|Palaeocene||66||El Kef Section,|||
|Upper Cretaceous||100.5||Mont Risoux,|||
|Upper Jurassic||163.5||Candidate sections:|
|Middle Jurassic||174.1||Fuentelsaz, Spain|||
|Lower Jurassic||201.3||Kuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria|
|Upper Triassic||235||Prati di Stuores, Dolomites, Italy|||
|Middle Triassic||247.2||Candidate sections:|
|Lower Triassic||252.2||Meishan, Zhejiang, China|
|Permian||298.9||Aidaralash, Ural Mountains, Kazakhstan|||
|Pennsylvanian||323.2||Arrow Canyon, Nevada, USA|||
|Mississippian||358.9||La Serre, Montagne Noire, France|||
|Devonian||419.2||Klonk, Prague, Czech Republic|||
|Silurian||443.4||Dob's Linn, Moffat, U.K.|||
|Cambrian||541||Fortune head section,|||
|Ediacaran||635||Enorama Creek section||
|Cryogenian||850||Defined chronometrically now. GSSP is in progress.|||
|Archaean & Hadean|
Global Standard Stratigraphic Age (GSSAs)[change | change source]
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[change | change source]
- "International Chronostratigraphic Chart 2012". 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)" (PDF). Episodes. 19: 77–81.
- "GSSP Rules". Geologic Timescale Foundation. Retrieved 28 November 2012.
- 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.
- 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.
- 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.
- 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.
- Silva, Isabella Premoli (1993). "Decision on the Eocene-Oligocene boundary stratotype" (PDF). Episodes. 16 (3): 379–382. Retrieved 14 September 2012. Unknown parameter
- 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.
- 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.
- 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.
- 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
- 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.
- 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.
- 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.
- 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.
- Paproth, Eva et al 1991. "Decision on the Devonian - Carboniferous boundary stratotype" (PDF). Episodes. 14 (4): 331–336. Retrieved 18 September 2012.
- "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 14 September 2012.
- Holland C.H. 1985. "Series and Stages of the Silurian System" (PDF). Episodes. 8 (2): 101–103. Retrieved 19 September 2012.
- 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.
- Brasier, Martin et al 1994. "Decision on the Precambrian-Cambrian boundary stratotype" (PDF). Episodes. 17 (1–2): 95–100. Retrieved 14 September 2012.
- 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.
- Plumb, K. A. (1991). "New Precambrian timescale" (PDF). Episodes. 14 (2). Retrieved 14 September 2012.