International Commission on Stratigraphy

International Commission on Stratigraphy
Abbreviation	ICS
Formation	1974
Type	INGO
Region served	Worldwide
Official language	English, French
Parent organization	International Union of Geological Sciences (IUGS)
Website	ICS Official website

The International Commission on Stratigraphy (ICS), sometimes referred to by the unofficial name "International Stratigraphic Commission" is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, geological, and geochronological matters on a global scale.

It is a subordinate body of the International Union of Geological Sciences—of which it is the largest body within the organisation—and of which it is essentially a permanent working subcommittee that meets far more regularly than the quadrennial meetings scheduled by the IUGS, when it meets as a congress or membership of the whole.

Aims

Units in geochronology and stratigraphy^[1]
Segments of rock (strata) in chronostratigraphy	Time spans in geochronology	Notes to geochronological units
Eonothem	Eon	4 total, half a billion years or more
Erathem	Era	10 defined, several hundred million years
System	Period	22 defined, tens to ~one hundred million years
Series	Epoch	34 defined, tens of millions of years
Stage	Age	99 defined, millions of years
Chronozone	Chron	subdivision of an age, not used by the ICS timescale

One of its main aims, a project begun in 1974, is to establish a multidisciplinary standard and global geologic time scale that will ease paleontological and geobiological comparisons region to region by benchmarks with stringent and rigorous strata criteria called Global Boundary Stratotype Section and Points (GSSPs) within the fossil record. (i.e. section of the rock record as of a core sample section or accessible exposed strata, which when a core sample are usually "trayed" in long pieces, also called "sections" about a meter in length.)

Methodology

Additionally the ICS defines an alternative type of benchmark and criteria called Global Standard Stratigraphic Ages (GSSAs) where the characteristics and dating criteria set solely by physical sciences methods (such as magnetic alignment sequences, radiological criteria, etcetera.) as well as encouraging an international and open debate amongst Earth scientists in the paleontology, geology, geobiology and chronostratigraphy fields, among others.

The International Commission on Stratigraphy has spawned numerous subcommittee level organizations organized and mobilized on a local country-wide or regional basis that are the true working committees of the IUGS, and these do the field work, basis comparisons in conference or co-ordination research committee meetings of local or wide-scale scope.

Publications

The ICS publishes various reports and findings as well as revised references periodically, summarized in the International Stratigraphic Chart, a combined working proposal and guideline-to-date released after the last ICS deliberations prior to the upcoming (next) meeting of the IUGS. Until the IUGS accepts the recommendations, they are unofficial since the IUGS parent approves or dismisses the individual deliberation reports of the ICS, which are presented as recommendations, and span dating and strata selection criteria, and related issues including nomenclatures. In de facto everyday matters, the deliberative results reported out of any meetings of the ICS are widely accepted and immediately enter everyday use, except in the rare cases where they result in a strong body of dissenting opinion, which matters are resolved before the full IUGS.

One such controversy arose in 2009 when the ICS deliberated and decided that the Pliocene Series of the current but unofficially named Quaternary Period should be shifted into the Neogene System and Neogene Period.^[2] The term Quaternary has yet to be officially adopted by the IUGS, but has widespread support as acceptable nomenclature for the current geologic period beginning at the GSSP accepted at 5,332,000 years ago at the transition between the Messinian Age to the Zanclean Age (3.6 mya). The ICS voted, perhaps because the time units span human paleo-archaeological strata, to begin the Quaternary at the end GSSP of the Piacenzian Age (2.588 mya) or possibly the end of the Gelasian (1.806 mya), any of which are in a different epoch.

References

↑ Cohen, K.M.; Finney, S.; Gibbard, P.L. (2015), International Chronostratigraphic Chart (PDF), International Commission on Stratigraphy .
↑ Riccardi, A.C. (30 June 2009). "Ratification of the definition of the base of Quaternary System/Period (and top of the Neogene System/Period), and redefinition of the base of the Pleistocene Series/Epoch (and top of the Pliocene Series/Epoch)" (PDF). International Union of Geological Sciences. Retrieved 30 December 2011.

External links

"ICS Subcommission for Stratigraphic Information". Home page. Retrieved May 25, 2010.
"International Chronostratigraphic Chart". Retrieved June 2014. Check date values in: |access-date= (help)

Time measurement and standards

Chronometry Orders of magnitude Metrology

International standards	UTC UTC offset UT ΔT DUT1 IERS ISO 31-1 ISO 8601 TAI 12-hour clock 24-hour clock Barycentric Coordinate Time Barycentric Dynamical Time Civil time Daylight saving time Geocentric Coordinate Time International Date Line Leap second Solar time Terrestrial Time Time zone

Obsolete standards	Ephemeris time Greenwich Mean Time Prime meridian

Time in physics	Absolute time and space Spacetime Chronon Continuous time Coordinate time Cosmological decade Discrete time Planck epoch Planck time Proper time Theory of relativity Time dilation Gravitational time dilation Time domain T-symmetry

Horology	Clock Astrarium Atomic clock Complication History of timekeeping devices Hourglass Marine chronometer Marine sandglass Radio clock Watch Water clock Sundial Dialing scales Equation of time History of sundials Sundial markup schema

Calendar	Astronomical Dominical letter Epact Equinox Gregorian Hebrew Hindu Intercalation Islamic Julian Leap year Lunar Lunisolar Solar Solstice Tropical year Weekday determination Weekday names

Archaeology and geology	Chronological dating Dating methodologies in archaeology Geologic time scale International Commission on Stratigraphy

Astronomical chronology	Galactic year Nuclear timescale Precession Sidereal time

Units of time	Century Day Decade Fortnight Hour Jiffy Lustrum Millennium Minute Moment Month Paksha Saeculum Second Shake Tide Week Year

Related topics	Chronology Duration music Mental chronometry Metric time System time Time value of money Timekeeper

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