Earth's oldest crystals reveal age of plate tectonics

rod

Oct 22, 2019
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My observation. The paper cited is Emergence of peraluminous crustal magmas and implications for the early Earth, 14-May-2021, http://www.geochemicalperspectivesletters.org/article2114/

Here are some interesting statements I see in the paper cited. “Detrital zircons from the Jack Hills (JH) metasedimentary belt of Western Australia are a record of the first ∼1.5 billion years of Earth history and can be used to help reconstruct the conditions of crust formation and secular changes therein. Beginning as early as ca. 4.3 Ga, but becoming more pronounced in the mid-Archean, a peraluminous signature begins to emerge from the JH zircon record…” Continental crust and its derivatives (e.g., detrital zircons) preserve a near continuous record of Earth’s history from ∼4.4. Ga to today (Voice et al., 2011) that can be used to investigate both individual magmatic systems (e.g., Reimink et al., 2014) and secular changes in Earth’s geodynamic and tectonic history (Bauer et al., 2020)… Whereas peraluminous granitic rocks dominate the bedrock geology in the AGC at ∼3.6 Ga (Reimink et al., 2019b), the peraluminous zircons that emerge in the JH record at ∼3.6 Ga are only a fraction of the total zircon population (∼10 %).”

These dates for very old samples of Earth is looking more and more crowded with astronomy. The Giant Impact for the origin of the Moon now can be dated some 4.4 to 4.45 billion years ago. https://phys.org/news/2020-07-younger-age-earth-moon.html, THE MOON MIGHT BE YOUNGER THAN WE THOUGHT, Sky & Telescope 140(5):11, 2020 "Abstract The newly formed Moon could have taken up to 10 times longer to solidify than we thought. If so, our satellite might be younger than previously estimated."

We have meteorites with ages dated in this period too and younger. https://ui.adsabs.harvard.edu/abs/2016LPICo1921.6440P/abstract, "Conclusion: Younger Ar/Ar step ages (3500 - 4400 Ma) for Bjurböle chondrule c2 suggest that the analysis of individual chondrules can yield more accurate meteorite ages than are obtainable from bulk samples."

https://ui.adsabs.harvard.edu/abs/2004GeCoA..68.3779D/abstract, "Older ages from high-T extractions may date an earlier impact event at 4.52 ± 0.08 Ga, whereas younger ages from lower-T extractions date a later impact event at 4.23 ± 0.03 Ga that may have caused annealing of feldspar and olivine."

https://ui.adsabs.harvard.edu/abs/2000GeCoA..64.2133B/abstract, "We made 39Ar- 40Ar age determinations of Watson, Techado, Miles, Colomera, and Sombrerete. Watson has an Ar-Ar age of 3.677 ± 0.007 Gyr, similar to previously reported ages for Kodaikanal and Netschaëvo. We suggest that the various determined radiometric ages of these three meteorites were probably reset by a common impact event."

We have microfossils dated 4.28 billion years old. 'Canadian bacteria-like fossils called oldest evidence of life', https://www.reuters.com/article/us-science-life-idUSKBN16858B, 01-March-2017

Some of the more recent age dating using zircons on Earth and life appearing on Earth 4.28 billion years ago, can get very interesting with astronomical dates.
 
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Catastrophe

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Here are some previous references:

Dating - The global tectonic rock cycle | Britannica
https://www.britannica.com › dating-geochronology

Continents move, carried on huge slabs, or plates, of dense rock about 100 km ... outer rock shell (the lithosphere) into a unifying theory called plate tectonics ... Combining knowledge of Earth processes observed today with absolute ages of ...


Age of the Seafloor (topography) Dataset | Science On a Sphere
https://sos.noaa.gov › datasets › age-of-the-seafloor-top...

Age of the Seafloor (topography) thumbnail. Description. The surface of the Earth is composed of a mosaic tectonic plates moving with respect to each other.


The evolution of plate tectonics | Philosophical Transactions of ...
https://royalsocietypublishing.org › doi › rsta.2017.0406


by RJ Stern · 2018 · Cited by 40 — A Neoproterozoic transition from single lid to plate tectonics also explains kimberlite ages, the Neoproterozoic climate crisis and the ...
What was Earth's tectonic... · ‎How did plate tectonics... · ‎When did plate tectonics...

Cat :)
 

rod

Oct 22, 2019
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I note this statement in the space.com article about Earth. "Ackerson said in a statement. "None of the other planets have continents or liquid oceans or life. In a way, we are trying to answer the question of why Earth is unique, and we can answer that to an extent with these zircons."

This exoplanet site shows 4728 confirmed exoplanets now, http://exoplanet.eu/

So far, none are confirmed with zircons or plate tectonics. Good question *why Earth is unique*.
 

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