Tonium

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Aeonothem Arathem system Age
( mya )
later later later
P
r
o
t
e
r
o
z
o
i
k
u
m

Duration:

1959
Ma 		Neoproterozoic
Jungproterozoikum
Duration: 459 Ma 		Ediacarium 541
⬍
635
Cryogenium 635
⬍
720
Tonium 720
⬍
1000
Mesoproterozoic
Mittelproterozoikum
Duration: 600 Ma 		Stenium 1000
⬍
1200
Ectasium 1200
⬍
1400
Calymmium 1400
⬍
1600
Paleoproterozoic
Altproterozoikum
Duration: 900 Ma 		Statherium 1600
⬍
1800
Orosirium 1800
⬍
2050
Rhyacium 2050
⬍
2300
Siderium 2300
⬍
2500
earlier earlier earlier
The following important information is missing from this article or section:
There is no biological development
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The tonium is a period in Earth's history that lasted 280 million years. Its beginning is geochronologically set at 1000 million years BP and its end at around 720 (until April 2016 at 720) million years BP. The tonium belongs to the Proterozoic , the third (penultimate) eon in the history of the earth. It forms the first (earliest) period within the most recent era of the Proterozoic, the Neoproterozoic . The tonium follows the stenium , the last period of the Mesoproterozoic , and is replaced by the cryogenium .

Naming

The name Tonium is derived from the ancient Greek τόνος (tόnos), to expand ( τείνειν ). He alludes to the further expansion of the old cratons .

geology

The outstanding geological event in the Tonium was the existence of a single supercontinent , Rodinia , which, however, began to disintegrate again at the end of the Tonium. The final decay can be located around 725 million years BP. Almost all of the cratons (the old mainland cores of today's continents) were already included in Rodinia. At the same time, there was a single gigantic ocean called Mirovia , which enclosed the mega-continent of Rodinia.

Mountain formation processes took place in the Tonium, although these are only partially known or researched. The beginning of the period coincides with the end of the Grenville Orogeny , an important mountain-building phase that occurred during the formation of Rodinia and during which u. a. Mountain ranges in what is now the east and southeast of North America and on what is now the Indian subcontinent were formed. The Grenville orogeny was around 980 million years BP the Rigolet Orogeny ended. During the Tonium itself u. a. the somewhat less important Edmundian Orogeny (approx. 1030 to 950 million years BP) took place, which formed parts of what is now Western Australia .

The early and middle Neoproterozoic (period 900 to 700 million years BP) are characterized in Laurentia by expansion tectonics in an east-west direction. This compared with the Mesoproterozoic completely new voltage regime (it had from 950 million years BP rotation of the tension of northeast-southwest to east-west taken place) should have about 200 million annual stock and is supported by numerous sedimentary formations in northern Arizona and central Utah documented .

In Europe ( Scotland and Baltica ) the Amazonia was docked from the south during the Grenville orogeny between 1100 and 1000 million years BP . The relatively soft collision without significant crust thickening affected the Midland Valley of Scotland and the basement of north-western Ireland in addition to the Svekonorwegids . Between 930 and 870 million years BP, Baltica broke away from Laurentia and Amazonia along a rift ditch . The opening rift was accompanied by a prolonged period of increased magmatism, granite intrusion and metamorphism (e.g. in southern Norway around 915 million years BP of post-tectonic granites and in Scotland by 870 million year old mafites and granite gneisses of the West Highlands belonging to the Glenfinnan Group and belong to the Loch Eil Group ).

The Svekonorwegids entered their main deformation phase from 1100 million years BP (D6) with granulite facial metamorphosis and two generations of granite intrusions. The late stage (D7) began from 1025 million years BP and dragged on to about 950 million years BP. After BP dolerite vaults had penetrated around 1025 million years ago , it came to north-south oriented folding and the penetration of medium-grain, late-Svekonorwegian granites. Then conjugated shear zones emerged and the folding style turned east-west. In the post-tectonic phase that began from 945 million years BP , the orogen was lifted out and covered by brittle fault tectonics . The post-tectonic phase is accompanied by two granite intrusion phases with medium-grain granites around 945 million years BP and post-tectonic granites around 915 million years BP. Metagabbro veins , which penetrated east-northeast-west- south -west and traversed 800 million years BP, mark the definitive end of the raised orogen, which was eventually reduced to a pre-Cambrian leveling area by 725 million years BP.

Biological development

From 850 to 800 million years BP, the earth had entered a second cycle of great environmental instability after a rest period of almost 1000 million years during the (so far unofficial) Rodinian . At the beginning of this interval, the stromatolites had experienced enormous expansion and diversification, but experienced a drastic species decline around 800 million years BP.

stratigraphy

Significant sedimentary basins and geological formations

Geodynamics

Orogenesis

Magmatism

literature

Web links

Individual evidence

  1. ^ Torsvik, TH et al.: Continental breakup and collision in the Neoproterozoic and Paleozoic: A tale of Baltica and Laurentia . In: Earth Science Reviews . tape 40 , 1996, pp. 229-258 .
  2. ↑ Starmer, IC: The Sveconorwegian Orogeny in southern Norway, relative to deep crustal structures and events in the North Atlantic Proterozoic Supercontinent . In: Norsk Geologisk Tidsskrift . tape 73 , 1993, pp. 109-132 .
  3. ↑ Grotzinger, JP and Knoll, AH: Stromatolites in Precambrian carbonates: evolutionary milestones or environmental dipsticks? In: Annual Reviews of Earth and Planetary Sciences . tape 27 , 1999, p. 313-358 .
  4. ↑ Guadagnin, F. et al .: Age constraints on crystal-tuff from the Espinhaço Supergroup - Insight into the Paleoproterozoic to Mesoproterozoic basin cycles of the Congo-São Francisco Craton . In: Gondwana Research . tape 27 , 2015, p. 363-376 .
  5. ↑ Starmer, IC: The Proterozoic evolution of the Bamble Sector shear belt, southern Norway: correlations across southern Scandinavia and the Grenvillian controversy . In: Precambrian Research . tape 49 , 1991, pp. 107-139 .
  6. ↑ Pedersen, S .: Rb-Sr age determinations on Late Proterozoic granitoids from the Evje area, South Norway . In: Bulletin of the Geological Society of Denmark . tape 29 , 1981, pp. 129-143 .