* Astronomy

Members Login
Post Info
TOPIC: Asteroid collision 470 million years ago


L

Posts: 128733
Date:
Asteroid collision 466 million years ago
Permalink  
 


Today's rare meteorites were common 466 million years ago

About 466 million years ago, there was a giant collision in outer space. Something hit an asteroid and broke it apart, sending chunks of rock falling to Earth as meteorites. But what kinds of meteorites were making their way to Earth before that collision?
In a study published Jan. 23 in Nature Astronomy, scientists tackled that question by creating the first reconstruction of the distribution of meteorite types before the collision. They discovered that most of the meteorites falling to Earth today are rare, while many meteorites that are rare today were common before the collision.
 
Read more



__________________


L

Posts: 128733
Date:
RE: Asteroid collision 470 million years ago
Permalink  
 


Unique meteorite from asteroid smash-up

Scientists have identified a completely new type of meteorite.
The 8cm space rock is said to be chemically distinct from any of the 50,000 other such objects held in collections.
Called Österplana 65, it was found in a limestone quarry in Thorsberg, Sweden, that produces floor tiles.
Dating suggests the meteorite's parent body was involved in a huge collision in the asteroid belt between Mars and Jupiter some 470 million years ago.

Read more



__________________


L

Posts: 128733
Date:
Permalink  
 

A piece of rock from the Highlands may help academics understand an event that changed the planet almost 500million years ago, according to Aberdeen University scientists.
They believe that a rock from Durness contains microscopic traces of a meteorite shower that caused earthquakes and tidal waves on the other side of the world 470million years ago.

Source

__________________


L

Posts: 128733
Date:
Permalink  
 

Microscopic meteorites found in Scotland have unveiled major clues about a catastrophic event which dramatically altered the Earths surface nearly 500 million years ago.
The evidence shows that life at this time, which was restricted to the seas, faced the consequences of an event far out in space.
Recent studies in Sweden have revealed that a massive collision in the asteroid belt between Mars and Jupiter resulted in thousands of meteorites landing on the Earth.
Studies by experts from the University of Aberdeen have now uncovered tiny remnants of meteorites, smaller than a grain of sand, within rocks exposed along the shore near Durness, which they believe can be tied to this event.  
The find has confirmed previous scientific speculation, that this meteorite shower was so vast in size that it affected locations across the globe including Scotland.

The study, led by Professor John Parnell from the School of Geosciences at the University of Aberdeen, has also shown that the meteorites falling to Earth may have been responsible for large earthquakes and tidal waves throughout the world.
The research, which has been published in Nature Geoscience this month, has revealed that in locations from China to the Yukon and Australia to Norway, large blocks of rock tumbled down slopes from shallow to deep water.
Pieces of rock the size of a football stadium also went sliding down hillsides in Korea, Argentina and the English Lake District.
These findings will now help scientists to investigate if there is any connection between the meteorites falling and the diversification of underwater species which took place around the same period.

Source

__________________


L

Posts: 128733
Date:
Permalink  
 

Evidence that a massive meteorite shower had an impact on Earth on a global scale 470 million years ago have been found on a Highlands beach.
Researchers from the University of Aberdeen uncovered tiny remnants of meteorites, smaller than a grain of sand, within rocks in Sutherland.
The find is linked to others made in China, the US and Australia.
The scientists think the meteorites - a result of a collision in space - triggered earthquakes and tsunami.
The university said the find near Durness confirmed previous scientific speculation that the meteorite shower - which followed a "catastrophic event" in an asteroid belt between Mars and Jupiter - was so vast in size that it affected locations across the globe.

Read more

__________________


L

Posts: 128733
Date:
Great Ordovician Biodiversification Event
Permalink  
 


Title: Asteroid breakup linked to the Great Ordovician Biodiversification Event
Authors: Birger Schmitz, David A. T. Harper, Bernhard Peucker-Ehrenbrink, Svend Stouge, Carl Alwmark, Anders Cronholm, Stig M. Bergström, Mario Tassinari & Wang Xiaofeng

The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval approx540 Myr ago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period1, 2, 3. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification approx470 Myr ago coincides with the disruption in the asteroid belt of the L-chondrite parent bodythe largest documented asteroid breakup event during the past few billion years4, 5. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroidssupported by abundant Middle Ordovician fossil meteorites and impact craters6accelerated the biodiversification process.

Read more

__________________


L

Posts: 128733
Date:
RE: Asteroid collision 470 million years ago
Permalink  
 


A shattered asteroid may have sprayed Earth with high-speed debris 470 million years ago and spurred one of the biggest bursts of biodiversity in Earth's history, rather than wiping life out.
The period of moderate to heavy meteorite bombardment appears to match the time at which many new species of animals evolved, called the Great Ordovician Biodiversification Event in the Middle Ordovician period.

Read more

__________________


L

Posts: 128733
Date:
Ordovician biodiversity
Permalink  
 


Space rocks are blamed for a lot of rough times on Earth, from the die-off of most marine animals some 250 million years ago to the disappearance of the dinosaurs 65 million years in the past.
A new theory, however, suggests that catastrophic meteorite impacts are linked to an explosion in biodiversity about 470 million years ago, during the Ordovician Period. Within a few million years, the number of trilobite species and scores of other creatures on Earth jumped at least three to four times.

460272865_48bb9611e0_m.jpg
Expand (315kb, 1024 x 741)
Credit Goniagnostus


Read more

-- Edited by Blobrana at 21:34, 2007-12-17

__________________


L

Posts: 128733
Date:
RE: Asteroid collision 470 million years ago
Permalink  
 


Having an asteroid break up as it approaches Earth is not the only way to end up with multiple craters.

Within the asteroid belt that orbits the sun between Mars and Jupiter, collisions between asteroids sometimes occur. The resulting fragments can then rain down on Earth. Simon Kelley, a geologist at the Open University in England, says that such a collision occurred 470 million years ago, and many of those fragments travelled to Earth. In fact, some of the fragments still are impacting Earth today.

Source

__________________


L

Posts: 128733
Date:
Permalink  
 

Vor knapp 500 Millionen Jahren ist offenbar ein Kleinplanet mit erheblicher Masse im Asteroidengürtel zwischen den Bahnen von Mars und Jupiter durch Kollision zweier Objekte auseinandergebrochen. Messungen Heidelberger Forscher um Mario Trieloff bekräftigen jetzt diese These, die bislang wegen zu ungenauer Altersangaben nicht hinreichend belegt werden konnte.

 Read more



__________________
1 2  >  Last»  | Page of 2  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard