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HPS-05 Recent developments in the Geologic Timescale

 

Adout perfection of geological time scale-2004

 

Vyacheslav Kulikov, Institute of Geology Karelian Researh Centre RAS (Russian Federation)
Viktoria Kulikova, Institute of Geology Karelian Researh Centre RAS (Russian Federation)
Yana Bychkova, Moscow State University (Russian Federation)
 

 

Making the Global chronostratigraphic scale, which should build on common principle of division of the Earth history is one of the most topically issue of the world geological community.The scale with base of Standard galactic year (SGY-215 Ma) was offering by authors in "The History of the Earth through galactic and solar cycles" (http://www.krc.karelia.ru/publ.php?id=616&plang=r). This scale presents cycle of Solar System rotation around the centre of the Galaxy. It consists of 22 SGY in the range from 4 655 Ma (approximately time of constitution of the solid Earth) to present days.
The borders of each SGY well-matched with boundaries of several Proterozoic eras and geological periods which marked in Geological Time Scale (GTS) (Gradstein et al, 2004).
Due to this fact, proposed scale may be used as specific calibration tool in perfection of GTS-2004 and its parts.
Authors propose to make following changes and addition to Archaean eon only. 1. To determine the lowest boundary of Archaean eon in the scope of 3 800 Ma as time of the constitution of reliable ancients sediment and volcanic rocks in the history of the Earth (Isua, Greenland).
2. To name Prearchaean eon of the Earth history as Priskoy, conforming to the rule of priority [Harlend et al., 1982, 1985] and leave out Eoarchaean era from GTS-2008.
Capacity and appellation of this eon's parts need further inquiry.
3. To mark out following periods in the Archaean eon (2 500 - 3 800 Ma), which consists of 3 eras.
Neoarchaean - CRATONIAN (2 500 - 2 650 Ma, hard, rigid (crathos): completion of Archaean sialic crust formation, supercontinent Pangaea - 0) and CHABOUSIAN (2 650 - 2 800 Ma, waterbody, basin (chabousia): first big Witwatersrand-type platform basins).
Mesoarchaean - CHLOROPETRIAN (2 800 - 3 000 Ma, green (chloros) and rock, stone (petra): global greenstone belts) and No named period (3 000 - 3 200 Ma).
Paleoarchaean - GNEISSIAN (3 200 - 3 400 Ma, gneiss (gneissios): formation of gneissis textured rocks, including some "grey gneisses"), MAGNESIAN (3400-3 600 Ma, magnesia: first komatiites and other Mg-rich magmatic rocks) and LITHOSIAN (3600-3 800 ìà, rock (lithos): oldest Isua type supracrustal rocks).
Suggested arrangement of names indicates momentous events of Earth history for each period on the Old Greek language.
Taking into consideration that duration of Precambrian and Phanerozoic periods determine in different parameters and first of them are longer than second in 2 - 6 times, it is expedient to first of all raise range to superperiods or specially fix it in comments.
During the creation of GTS-2008 some of proposed names may be changed to more convenient.

 

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