New evidence points to the role of plate tectonics in early Earth’s release of internal heat and the swapping of geomagnetic poles.
Illustration by Alec Brenner
There really are grown adults who believe Earth was magicked into existence, as is. less than 10,000 years ago!
And these ignorant people exist despite evidence such as this paper, that there were continental movements, known to geologists as plate tectonics, billions of years before they believe Earth was magicked up by a spell from an invisible magician, the existence of which has never been explained, let alone demonstrated with evidence, and the modus operandum which has never been observed.
And, if that wasn't bad enough for the Creation cult, the paper even alludes to the geological clock that has been recording the magnetic reversals of Earth that have occurred 183 times in the last 83 million years and perhaps several hundred times in the past 160 million years, according to NASA.
The scientists led by Harvard geologists, Alec Brenner and Roger Fu, point out that the stability of the early Earth, where basically the same tectonic forces were working as are working still, means the conditions were conducive to the appearance and evolution of self-replicating systems we call life.
As the Harvard Gazette article by Juan Siliezar explains:
New research analyzing pieces of the most ancient rocks on the planet adds some of the sharpest evidence yet that Earth’s crust was pushing and pulling in a manner similar to modern plate tectonics at least 3.25 billion years ago. The study also provides the earliest proof of when the planet’s magnetic north and south poles swapped places. The two results offer clues into how such geological changes may have resulted in an environment more conducive to the development of life on the planet.In the abstract to their published open access paper in PNAS, the scientists say:
The work, described in PNAS and led by Harvard geologists Alec Brenner and Roger Fu, focused on a portion of the Pilbara Craton in Western Australia, one of the oldest and most stable pieces of the Earth’s crust. Using novel techniques and equipment, the researchers show that some of the Earth’s earliest surface was moving at a rate of 6.1 centimeters per year and 0.55 degrees every million years.
That speed more than doubles the rate the ancient crust was shown to be moving in a previous study by the same researchers. Both the speed and direction of this latitudinal drift leaves plate tectonics as the most logical and strongest explanation for it.
“There’s a lot of work that seems to suggest that early in Earth’s history plate tectonics wasn’t actually the dominant way in which the planet’s internal heat gets released, as it is today, through the shifting of plates,” said Brenner, a Ph.D. candidate in the Graduate School of Arts and Sciences and a member of Harvard’s Paleomagnetics Lab. “This evidence lets us much more confidently rule out explanations that don’t involve plate tectonics.”For example, the researchers can now argue against phenomena called “true polar wander” and “stagnant lid tectonics,” which both can cause the Earth’s surface to shift but aren’t part of modern-style plate tectonics. The results lean more toward plate tectonic motion because the newly discovered higher rate of speed is inconsistent with aspects of the other two processes.Geologists Alec Brenner and Roger Fu, focused on a portion of the Pilbara Craton in Western Australia, one of the oldest and most stable pieces of the Earth’s crust.
Photo by Roger Fu
In the paper, the scientists also describe what’s believed to be the oldest evidence of when Earth reversed its geomagnetic fields, meaning the magnetic North and South Pole flipped locations. This type of flip-flop is a common occurrence in Earth’s geologic history, with the poles reversing 183 times in the last 83 million years and perhaps several hundred times in the past 160 million years, according to NASA.
The reversal tells a great deal about the planet’s magnetic field 3.2 billion years ago. Key among the implications is that the magnetic field was likely stable and strong enough to keep solar winds from eroding the atmosphere. This insight, combined with the results on plate tectonics, offers clues to the conditions under which the earliest forms of life developed.
Today, the Earth’s outer shell consists of about 15 shifting blocks of crust, or plates, which hold the planet’s continents and oceans. Over eons the plates drifted into each other and apart, forming new continents and mountains and exposing new rocks to the atmosphere, which led to chemical reactions that stabilized Earth’s surface temperature over billions of years.It paints this picture of an early Earth that was already really geodynamically mature. It had a lot of the same sorts of dynamic processes that result in an Earth that has essentially more stable environmental and surface conditions, making it more feasible for life to evolve and develop.
Alec R. Brenner lead author
Department of Earth and Planetary Sciences
Harvard University, Cambridge, MA, USA.
Evidence of when plate tectonics started is hard to come by because the oldest pieces of crust are thrust into the interior mantle, never to resurface. Only 5 percent of all rocks on Earth are older than 2.5 billion years old, and no rock is older than about 4 billion years.
Overall, the study adds to growing research that shows that tectonic movement occurred relatively early in Earth’s 4.5-billion-year history and that early forms of life came about in a more moderate environment. In 2018, members of the project revisited the Pilbara Craton, which stretches about 300 miles across. They drilled into the primordial and thick slab of crust there to collect samples that, back in Cambridge, were analyzed for their magnetic history.Finally being able to reliably read these very ancient rocks opens up so many possibilities for observing a time period that often is known more through theory than solid data. Ultimately, we have a good shot at reconstructing not just when tectonic plates started moving, but also how their motions — and therefore the deep-seated Earth interior processes that drive them — have changed through time.
Professor Roger R. Fu,
Department of Earth and Planetary Sciences,
Harvard University, Cambridge, MA. USA
Using magnetometers, demagnetizing equipment, and the Quantum Diamond Microscope — which images the magnetic fields of a sample and precisely identifies the nature of the magnetized particles — the researchers created a suite of new techniques for determining the age and way the samples became magnetized. This allows the researchers to determine how, when, and in which direction the crust shifted as well as the magnetic influence coming from Earth’s geomagnetic poles.
The Quantum Diamond Microscope was developed in a collaboration between Harvard researchers in the Departments of Earth and Planetary Sciences (EPS) and of Physics.
For future studies, Fu and Brenner plan to keep their focus on the Pilbara Craton while also looking beyond it to other ancient crusts around the world. They hope to find older evidence of modern-like plate motion and when the Earth’s magnetic poles flipped.
SignificanceJust another example there of how Creationism is refuted quite incidentally, simply by revealing the real world evidence with which it is of course entirely inconsistent simply because the people who made up the origin myths in the Bronze Age were entirely ignorant of the science. Incidentally, it's also an example of the way different strands of evidence mesh so neatly to support the idea that life originated on Earth several billion years ago, just as you would expect if the current theories were correct.
The modern Earth is geologically dynamic. Convection in its rocky mantle drives plate tectonics that reshapes its surface, and currents inside its metallic core generate a strong planetary magnetic field. However, it is uncertain whether these processes had begun to shape Earth in its deep past. Our measurements of magnetic signals preserved in 3.25-billion-year-old rocks provide the earliest quantitative evidence of both rapidly moving crust—a hallmark of plate tectonics—and a stable ancient magnetic field that episodically alternated polarity. These observations suggest that the early Earth was remarkably geologically mature from its surface to its deep interior, potentially contributing to stable surface conditions for the evolution of early life.
Abstract
The paleomagnetic record is an archive of Earth’s geophysical history, informing reconstructions of ancient plate motions and probing the core via the geodynamo. We report a robust 3.25-billion-year-old (Ga) paleomagnetic pole from the East Pilbara Craton, Western Australia. Together with previous results from the East Pilbara between 3.34 and 3.18 Ga, this pole enables the oldest reconstruction of time-resolved lithospheric motions, documenting 160 My of both latitudinal drift and rotation at rates of at least 0.55°/My. Motions of this style, rate, and duration are difficult to reconcile with true polar wander or stagnant-lid geodynamics, arguing strongly for mobile-lid geodynamics by 3.25 Ga. Additionally, this pole includes the oldest documented geomagnetic reversal, reflecting a stably dipolar, core-generated Archean dynamo.
Brenner, Alec R.; Fu, Roger R.; Kylander-Clark, Andrew R. C.; Hudak, George J.; Foley, Bradford J.
Plate motion and a dipolar geomagnetic field at 3.25 Ga
Proceedings of the National Academy of Sciences (PNAS); 119(44), e2210258119. DOI:10.1073/pnas.2210258119.
Copyright: © 2022 The authors. Published by PNAS. Open access
Reprinted under a Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).
Even more amazing than the fact the otherwise normal people believe the childish Bronze Age Creation myths despite this sort of refutation, is that these same people are prepared to perform the most idiotic mental gymnastics to dismiss them, as though being ignorant of scientific evidence is something to take great pride in, because their mummies and daddies were also ignorant of them.
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