Impact Craters On Our Earth

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
13,612
Likes
15,896
Points
309
Location
Out of Bounds
#32
Could this asteroid have brought life to earth?
No ... The oldest definitive evidence of simple biological life on earth pre-dates the Lake Acraman impact by circa 3 billion years. Accepting more recent strongly suggestive evidence would push that horizon back to over 4 billion years ago.


This event coincides with the emergence of the Ediacaran - earliest life forms discovered. ...
The Ediacaran is the period during which the earliest complex multicellular organisms are known to have been present (based on evidence to date). These represent the earliest multicellular organisms with differentiated / specialized internal tissues (as opposed to a collective comprised of one type of cell).
 
Joined
May 30, 2010
Messages
7,465
Likes
7,156
Points
284
#33
Thanks. Gostin supposes that the Acraman event coinciding with Ediacaran glaciation could have caused a biotic crisis which stimulated biotic evolution.
 

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
13,612
Likes
15,896
Points
309
Location
Out of Bounds
#34
Thanks. Gostin supposes that the Acraman event coinciding with Ediacaran glaciation could have caused a biotic crisis which stimulated biotic evolution.
That may well have happened. It's been known for a long time that the Ediacaran glaciation had global ecological and biological ramifications. The effects of an impactor the apparent size of the Lake Acraman whatever-it-was would have been an additional destabilizing factor.

Not much is known about the Ediacaran biota and how they relate to the later Cambrian organisms. The available evidence can support either (a) a relatively abrupt global shift from the earlier to the later forms or (b) some sort of less dramatic evolutionary progression for which we've not yet found any evidence.
 
Joined
May 30, 2010
Messages
7,465
Likes
7,156
Points
284
#35
re EG's correction above;
Nearby quartzite rocks contain Ediacaran fossils, the oldest soft-bodied organisms ever discovered.

The Ediacaran Period is named after the hills that contain these fossils, and is indicated by a bronze plaque known as a golden spike — the only one in the Southern Hemisphere.

Source = previous ABC link

Just as an aside, I stumbled upon the Golden Spike quite by accident roaming near the Trezona campground a few years ago. What a moment. I was heading back there yesterday when my car engine shat itself and I had to turn around and come home.
 
Joined
May 30, 2010
Messages
7,465
Likes
7,156
Points
284
#36
Not much is known about the Ediacaran biota and how they relate to the later Cambrian organisms. The available evidence can support either (a) a relatively abrupt global shift from the earlier to the later forms or (b) some sort of less dramatic evolutionary progression for which we've not yet found any evidence.
I am considering heading in that direction professionally in life 2.0. Geological time fascinates me deeply.
 

gordonrutter

There must be a set character limit to this opt...
Staff member
Joined
Aug 3, 2001
Messages
2,174
Likes
2,214
Points
184
#40
Ah, you saw the graphic on The Phenomenix today, too!
Guilty as charged and I noticed the new post here and thought it was too good an opportunity to miss. Erm, I mean no, I came up with this all by myself
 

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
13,612
Likes
15,896
Points
309
Location
Out of Bounds
#42
A new analysis indicates the Wolfe Creek Crater (in Western Australia) is less than half as old as previously believed ...
New Analysis Just Changed The Original Date of a Massive Meteorite Crater in Australia

n the state of Western Australia sits the famous Wolfe Creek crater, the aftermath of a 14,000-tonne meteorite crashing into Earth thousands of years ago. A new study now claims the impact happened far more recently than we suspected, prompting a rethink on how often giant space rocks actually strike our planet.

A team of researchers from universities in Australia and the US took a close look at several features of the crater's underlying rock to get a precise measurement on the age of Wolfe Creek's most famous landmark.

Previous estimates have stated the crater could be 300,000 years old, but the new result places it much closer to our time, perhaps as little as 120,000 years ago. ...
FULL STORY: https://www.sciencealert.com/one-of...med-far-more-recently-than-previously-thought
 
Top