Panthalassa
Panthalassa ( Greek Πάν "everything" and Θάλασσα "sea") is the name of a global ocean which , according to the theory of plate tectonics, surrounded the global supercontinent Pangea in the geological ages of the late Paleozoic and early Mesozoic - 300 to 150 mya . The Panthalassa is also considered to be the primordial Pacific or today's Pacific basin can be understood as the remainder of the Panthalassa.
The former supercontinent Rodinia - 1100 to 800 mya - was surrounded by Mirovia , the forerunner of the Panthalassa.
The Pacific Ocean today covers around 35% of the earth's surface with 181 million km², the Atlantic Ocean with 90 million km² over 17% and the Indian Ocean with 76 million km² just under 15%. Assuming that the size of the Indian Ocean is roughly the same as that of the Tethys , and the ratio of land to water in the Paleozoic Era was the same as it is today, Panthalassa should have occupied over 50% of the earth's surface.
Assuming the same spread rates in the Atlantic and Panthalassa / Pacific, the oceanic crust of the old Panthalassa basin would have been subducted in the order of twice the area of the Atlantic basin (almost 35% of the earth's surface) since the opening of the Atlantic around 200 million years ago . However, since the spreading rates on the East Pacific Ridge were significantly higher than on the Mid-Atlantic Ridge and are still today, far more lithosphere was actually subducted. For North America alone, lithosphere subduction over the past 200 million years is assumed to be equivalent to that of the entire Pacific basin of today.
development
Since in the course of Earth's history , the plate tectonic distribution of land and water masses by the constant
- Rift zone formation and hot spot volcanism of the lithosphere
- Ocean floor spreading
- Subduction of the oceanic plates and the general
- Continental drift of the continental plates or cratons
changed, several prehistoric oceans can be distinguished. It existed next to or in the global ocean Panthalassa from about:
- Triassic - 240 mya - the Tethys forms an eastern bay of Pangea .
- Ediacarium to the Paleozoic - 600 mya to 300 mya - the Proto-Tethys and the Palaeotethys , the Iapetus Ocean , the Khanty-Mansi Ocean and the Rheic Ocean form as sub-oceans in the global Panthalassa.
- Cryogenium - 750 mya - Mirovia freezes up to two kilometers deep around the South Pole. The Pan-African Ocean forms a bay of what is now the Panthalassa and surrounds Gondwana, the part of Rodinia that was then closer to the equator .
- Stenium - 1100 mya - Mirovia surrounds the emerging Rodinia as a forerunner of Panthalassa.
See also
Web links
Individual evidence
- ^ Gary L. Pavlis, Karin Sigloch, Scott Burdick, Matthew J. Fouch, Frank L. Vernon: Unraveling the geometry of the Farallon plate: Synthesis of three-dimensional imaging results from USArray. Tectonophysics. Vol. 532-535, 2012, pp. 82-102, doi : 10.1016 / j.tecto.2012.02.008 .