Impact Craters On Our Earth

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
17,546
Reaction score
23,155
Points
309
Location
Out of Bounds
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).
 

skinny

Class of 1984
Joined
May 30, 2010
Messages
7,827
Reaction score
7,866
Points
294
Location
Adelaide
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
17,546
Reaction score
23,155
Points
309
Location
Out of Bounds
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.
 

skinny

Class of 1984
Joined
May 30, 2010
Messages
7,827
Reaction score
7,866
Points
294
Location
Adelaide
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.
 

skinny

Class of 1984
Joined
May 30, 2010
Messages
7,827
Reaction score
7,866
Points
294
Location
Adelaide
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
3,436
Reaction score
4,705
Points
184
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
17,546
Reaction score
23,155
Points
309
Location
Out of Bounds
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
 

Comfortably Numb

Antediluvian
Joined
Aug 7, 2018
Messages
5,633
Reaction score
8,813
Points
279
Location
Phone
Crater found from asteroid that covered 10% of Earth's surface in debris

The crater sits beneath a plain of hardened lava that formed after the asteroid impact, which occurred nearly 800,000 years ago.

Source: Astronomy online
Date: 3 January, 2020

A flash of light would have come first, followed by a shockwave and massive earthquake. Only later would the hailstorm of black, glassy debris begun to fall, a rocky rain that would touch ten percent of the planet's surface.

That's the scene that followed a massive asteroid impact 790,000 years ago. The remains it scattered, called tektites, have been found from Asia to Antarctica. For decades, scientists have searched for the elusive resting place of the impactor that coated the Earth with debris. Now, they may have finally found it.

A new report published in the Proceedings of the National Academy of Sciences says that the meteorite likely struck in southern Laos, carving a 10.5 by eight mile crater now covered by a lava flow.

The find helps reconstruct some of the chaos that ensued after impact, says study co-author Kerry Sieh, a geologist at Nanyang Technological University in Singapore. It could also illustrate some of what we could expect if a similarly large asteroid were to hit Earth again.

https://astronomy.com/news/2020/01/...d-that-covered-10-of-earths-surface-in-debris
 

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
17,546
Reaction score
23,155
Points
309
Location
Out of Bounds
... Now, geologists have added a much deeper layer of history to those rocks by showing they were forged 2.229 billion years ago, when an asteroid crashed into our planet. The finding makes Yarrabubba crater, the 70-kilometer-wide scar left by the collision, Earth’s oldest. ...
Newly-published research has confirmed the age of the Yarrabubba crater and its status as the oldest known impact site on our planet.

Overview:
https://www.sciencealert.com/a-crater-in-australia-is-earth-s-oldest-known-meteoroid-impact

Published report:
https://www.nature.com/articles/s41467-019-13985-7
 
Top