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Posibble old Asteroide impact on earth with 1000km diameter !
Open google earth on following coorinates "South Sandwich Islands" and
zoom out to 6000 km: 58° 7'28.20"S 26°13'7.85"W You can see a big under water crater, and you see an impact path how the crater was created, the impact begins on the South pole "SAWB BASE MARAMBIO" and on the bottom of South American's "Falkland Islands / Malwinen". It seems that south pole and south america was 1 continent which were hit by a asteroide of a diameter of 1000 km and than splitted the continent! What do you think how this rock mass was created ? |
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Posibble old Asteroide impact on earth with 1000km diameter !
On Wed, 7 May 2008 01:01:20 -0700 (PDT), chillax wrote:
It seems that south pole and south america was 1 continent which were hit by a asteroide of a diameter of 1000 km and than splitted the continent! No, that's not the cause of the structure you see. Between the large South American Plate, and the large Antarctic Plate, you have the Scotia Plate. The South Sandwich Islands are a typical volcanic island arc lying over a subduction zone between the plates. BTW, a collision with a 1000 km diameter object would result in the destruction of virtually all life on Earth. Such an event, if it has ever occurred, would have been billions of years ago, and no obvious visible evidence would remain. The area around the Scotia Plate is very active geologically; a smaller impact in that area would become invisible in just a few million years. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
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Posibble old Asteroide impact on earth with 1000km diameter !
chillax wrote: Open google earth on following coorinates "South Sandwich Islands" and zoom out to 6000 km: 58° 7'28.20"S 26°13'7.85"W You can see a big under water crater, and you see an impact path how the crater was created, the impact begins on the South pole "SAWB BASE MARAMBIO" and on the bottom of South American's "Falkland Islands / Malwinen". It seems that south pole and south america was 1 continent which were hit by a asteroide of a diameter of 1000 km and than splitted the continent! What do you think how this rock mass was created ? By a massive outgrowth of asparagus! |
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Posibble old Asteroide impact on earth with 1000km diameter !
Chris L Peterson wrote:
BTW, a collision with a 1000 km diameter object would result in the destruction of virtually all life on Earth. Such an event, if it has ever occurred, would have been billions of years ago, and no obvious visible evidence would remain. The area around the Scotia Plate is very active geologically; a smaller impact in that area would become invisible in just a few million years. Hi, Chris. Just to share my own immediate if a bit more amateurish agreement: this would be an impact involving a body approximately the size of 1 Ceres, a "dwarf planet" according to IAU terminology, or a small "macroplanet" as I like to say (large enough to attain hydrostatic equilibrium, i.e. collapse by self-gravity into a near-spherical or "globose" shape). The one event on this scale, or rather larger, that I can think of is that postulated in the Theia scenario for the origins of our Moon, where we have the Earth sharing its orbit with another planet about the size of Mars in 1:1 resonance, a bit like Jupiter and the Trojan asteroids. Then things get destablized, and there's a sort of collision -- at a shallow angle, according to one version I've seen. The name "Theia" is appropriately that of a Titan who, in a Greek creation story, gave birth to the Moon. I guess that this would have been fairly soon after the formation of the Solar System -- say 4.5 Ga (i.e. in geospeak, 4.5 gigayears ago). An interesting point is that while Theia was in a stable 1:1 resonance with Earth, we could call Earth a "dominant macroplanet," or IAU "planet," which means that the Earth had attained hydrostatic equilibrium, and had a dramatically greater mass than all objects in the neighborhood of its orbit _not under its gravitational control or influence_. However, when Theia got out of a stable resonance, making a collision possible, Earth might temporarily become a "belt macroplanet" or IAU "dwarf planet" -- massive enough for hydrostatic equilibrium, but no longer having "cleared the neighborhood of its orbit," because Theia would be there and out of Earth's control! Then we have the collision -- with part of Theia getting assimilated by the Earth, and most of the rest becoming the Moon -- a satellite, and thus again under control, so that the Earth has "cleared the neighborhood of its orbit." A nicety: I guess that if one thinks in terms of Earth's _ability_ to clear its orbit within a reasonable time, then one could argue that it remained a dominant planet (or IAU planet) even during the time when Theia was loose, since we know that when the collision happens, Earth is in an orbital situation where it's going to "clear its neighborhood." Then came the Late Heavy Bombardment (ca. 4.2-3.8 Ga, as I recall), with lots of impacts -- I wonder if there's any hypothesis as to how big the largest impactors might have been in that era. Sometimes this era is described as a "rain of planetesimals," which might suggest to me sizes of around 1-100 km, plus lots of smaller objects also. An interesting question is whether this may have interrupted the early origins of life, or helped out the process by bringing in more organic materials. Some paleobiologists have suggested possible evidence for "chemical fossils" in the Isua greenbelt rocks (about 3.8 Ga), while there is widespread acceptance of microfossils around 3.5 Ga -- although not always a consensus about which examples from this epoch are the most convincing. Anyway, the K-T or Cretaceous-Tertiary event of 63 Ma (megayears or millions of years) ago has been hypothesized to have involved an impactor of around 10km -- two orders of magnitude less than 1000km! With many thanks, Margo |
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