Earth's mid-life crisis – new research backs 'lull' in the geologic record

Earth
A composite image of the Western hemisphere of the Earth. Credit: NASA

New research backing claims that the Earth experienced a 'geological lull' in its development around 2.3 to 2.2 billion years ago has just been released by Curtin University.

Published today in Nature Geoscience, the research is likely to re-ignite debate over the Earth's development, with scientists divided over what geologic processes occurred during the Palaeoproterozoic geologic era.

Lead researcher Dr. Christopher Spencer from the School of Earth and Planetary Sciences at Curtin University said the research findings point to a near complete shutdown of continental magmatism during this period, and has profoundly shaped the as we know it today.

"Our research shows a bona fide gap in the Palaeoproterozoioc geologic record, with not only a slowing down of the number of volcanoes erupting during this time, but also a slow-down in sedimentation and a noticeable lull in tectonic plate movement," Dr. Spencer said.

"The early Paleoproterozoic was a significant time in Earth history. It was at this time when the atmosphere got its first whiff of oxygen and also the first global glaciation event. But this was also a period where other geologic processes effectively shut down. It's almost as if the Earth experienced a mid-life crisis."

The research involved compiling massive amounts of existing geological data as well as examination of rocks collected in Western Australia's Stirling Ranges, China, Northern Canada and Southern Africa.

"The more rocks and data we collected the clearer it is that there is very little preserved record for this period," Dr. Spencer said.

"Earth's mantle used to be much hotter than it is today and over time volcanoes allowed the mantle to cool and geologic processes are thought to have slowed down. We believe this continual slowdown led to dramatic geological changes such as those seen in the early Paleoproterozoic.

"This 'dormant' period lasted around 100 million years and signalled what we believe was a shift from 'ancient-style' tectonics to 'modern-style' tectonics more akin to those operating in the present day. Following this dormant period Earth's geology started to 'wake-up' again around 2.2 to 2.0 billion years ago with a 'flare-up' of volcanic activity and a shift in the composition of the continental crust."

Dr. Spencer believes these findings could provide greater insight into our understanding of the world's natural resources and where they exist, and has suggested more research is now needed into this time period to better determine how the 's geological processes were impacted.

The full research paper has been published in Nature Geoscience.


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More information: Christopher J. Spencer et al. A Palaeoproterozoic tectono-magmatic lull as a potential trigger for the supercontinent cycle, Nature Geoscience (2018). DOI: 10.1038/s41561-017-0051-y
Journal information: Nature Geoscience

Provided by Curtin University
Citation: Earth's mid-life crisis – new research backs 'lull' in the geologic record (2018, January 30) retrieved 23 May 2019 from https://phys.org/news/2018-01-earth-mid-life-crisis-lull-geologic.html
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Jan 30, 2018
Perhaps "lull" isn't the correct term.

One would suspect that this slowdown actually represents a switch from a higher-energy equilibrium state to a lower one, specifically in terms of internal heat, as ongoing cooling crossed some thermochemical threshold.

Jan 30, 2018

Not a single event but a series of coincidences?
As possible causation for these results.

Was there a lull in the bombardment of Earth from the debris remaining throughout the Solar System?

The radioactive material in the early crust/mantle. Was a large portion of that absorbed deeper into the Earth? Depleting the radiate heat, those heavy metals produced? And/or, was a large portion of crustal material past the random half-life point, decreasing heat produced?

Not sure if there is even a way to test for this speculation. Would it have been likely or even possible that our Sun was also going through a maturity phase? And outputting less solar radiation during that period?

Jan 31, 2018
""The more rocks and data we collected the clearer it is that there is very little preserved record for this period," Dr. Spencer said." ....
Perhaps Dr. Spencer looked in all the WRONG places for the correct evidence. As a PhD Vertebrate Paleontologist (Univ of Chicago), I look at Dr. Spencer's statements and analysis and have to laugh seeing once again Geologists and :"Planetary Scientists" ignoring Biology (history) completely in providing answers and clues as to the process of Earth's evolution. Spencer himself says that at 2.5 Billion years ago Earth was experiencing it's first "whiffs of oxygen". He's actually wrong as it was 2.3 Billion Years that we first find evidence of sulfur-eating bacteria, the foundation of life on Earth that would begin evolution and the creation of Oxygen on Earth. 200,000 years difference is a big deal, because it indicates that during this absurd claimed "geologic lull" things on Earth WERE CHANGING. Life needs geologic changes to evolve.

Jan 31, 2018
pd, you bring up an interesting point. It is noticeable that a number of the articles on this site assume "That a single swallow makes a summer."

pd, since you have completed a meticulously thorough, global spanning search of all known and unknown geological formations. And now have conclusive proof that your findings must dictate the results of other research discoveries.

May I suggest you correlate your findings with Dr. Spencer's work and see if there is any possibility that you are both correct? Just about different things.

Jan 31, 2018
rrwillsj - I don't need to do a " complete a meticulously thorough, global spanning search of all known and unknown geological formations", we have 100 years of sound and proven Paleontological research done at far more vaunted, credible institutions than that from Curtain U. Kick around all the rocks you want, Spencer's hypothesis does not correlate with what we KNOW and has been PROVEN about the evolution of life on Earth between 2.5 and 1 Billion Years ago. Evolution is about adapting to CHANGING CONDITIONS, a "Lull" is not so. Those of us in Paleontology with Biological, Zoological or Botanical backgrounds know that rocks have nothing to do with the study of life, so I might not expect you, likely a geologist, to understand life and evolution and how they work as a result of the changing Earth over 4.5 Billion Years. I'm reminded of the decades ago when Geologists with no Biology or Zoology training pretended to be Paleontologist and put the wrong fossil heads on Dinosaur exhibits.

Feb 01, 2018
So, pd, see if I got this speculation wrong. You are a sore loser of the funding competitions between your university's departments.

Frankly, I'd be pissed also.

Feb 01, 2018
Hey guys,

Just in case you missed it, they are referring specifically to GEOLOGIC processes here, not Biologic.

Also, WRT your first comment, paleo, 0.2 billion years = 200 million years, and not 200 thousand.

Just so you know.

Feb 01, 2018
rrwillsj - You are doing an exemplary job of ignoring facts given and only proving the moron you obviously are. You should worry less about being "pissed too" and worry more about seeking mental health help.

Caliban - "Geologic processes" are shown and proven to affect biological processes. Time for you to go back to school of a higher educational level, if you ever actually went previously.

Feb 02, 2018
Silly me! I was thinking that it was geological formations from biological processing.

gs, be a pal and call up all those guys wasting their time fracking shale, mining coal and quarrying sandstone? To be sure to turn the lights off behind them when they close up business to fulfill your dictate.

Feb 02, 2018
rrwillsj - You are doing an exemplary job of ignoring facts given and only proving the moron you obviously are. You should worry less about being "pissed too" and worry more about seeking mental health help.

Caliban - "Geologic processes" are shown and proven to affect biological processes. Time for you to go back to school of a higher educational level, if you ever actually went previously.


geostorm,

Yes, indeed geologic processes affect biologic ones. In fact, they are locked in a feedback loop.

However, it obviously needs pointing out that that the orders-of-magnitude larger driving force for geologic processes is the Earth's internal heat, which is responsible for plate tectonics, and preceeds biological life on Earth.

How did you like today's lesson on your trip back to school?

Feb 05, 2018
Not sure if there is even a way to test for this speculation
You could record how many people laugh their asses off at it -?
pd, you bring up an interesting point. It is noticeable that a number of the articles on this site assume "That a single swallow makes a summer."
-and you could record the growing number of posters on this site who take great offense at your gratuitous pissing on the work of genuine scientists.

That might help. A little.

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