January 26, 2023

Unraveling Earth’s Mysteries: Continental Growth Is Not a Continuous Process

The continents, a specific function of our planet, still hold numerous secrets. Using chemical data on sedimentary rocks compiled from the scientific literature from the 1980s to today day, CNRS researcher Marion Garçon has actually uncovered a brand-new geological history of the continents. She reveals that their development was not a constant procedure, and that they have actually constantly been rich in silica. [1] This brand-new research study, published on September 22, 2021, in Science Advances, calls into question particular models of the beginning of plate tectonics and provides us with a much better understanding of continental growth through time.
The continents which number five, six, 7, or even more depending on the design utilized are still shrouded in secret. They comprise the emerged part of the Earths continental crust. The continents have actually differed reliefs along with rocks of different structures and ages, and this variety makes them difficult to study.
Marion Garçon, a CNRS scientist at the Laboratoire magmas et volcans (CNRS/ IRD/ Clermont Auvergne University) studied a compilation of information uniting information on sedimentary rocks with ages varying from 3.7 billion years ago to the present day. Using chemical data obtained since the 1980s, the researcher took a fresh appearance at the sedimentary rock record. In this brand-new study, she had the ability to draw 2 conclusions that bring into question particular models and theories on continental growth.

At top: Changes over time in the average silica (SiO2) material of the continents. Continental crust has actually always been abundant in silica compared to the more silica-poor oceanic crust.
Her first conclusion is that the continents have actually constantly been silica-rich. On average, silica comprises 67% of continental mass, and its material has actually never fallen below 60% throughout Earths history. This very first discovery remains in contradiction with models that suggest that the continents were fairly depleted in silica however abundant in iron and magnesium at the beginning of Earths history.
There have been 6 significant periods of continental growth, taking place every 500-700 million years over the previous 3.7 billion years. These events enabled the continents to grow to the size they are today.
Throughout our worlds history, supercontinents have actually experienced periods of break up and assembly with a frequency near to that of the six episodes of continental development discovered in this study. Although no correlation can presently be established in between these events, this might assist to guide future research study. Garçons work sheds brand-new light on the composition and development of continents gradually, making it possible to refine geological models and thus pave the method for new research studies.
Notes

Among Earths special features is that it has continents.
Contrary to numerous theories, the continents have actually constantly been rich in silica (which is discovered in quartz for instance).
The continents did not form constantly in time but arise from episodic events throughout Earths history.

Silica (SiO2) is a chemical compound that is found in many minerals such as quartz. It is also the primary element of the Earths continental crust.

Utilizing chemical information on sedimentary rocks compiled from the clinical literature from the 1980s to the present day, CNRS researcher Marion Garçon has uncovered a new geological history of the continents. The continents which number 5, 6, seven, or even more depending on the model used are still shrouded in secret. The continents have actually varied reliefs as well as rocks of different structures and ages, and this diversity makes them difficult to study.
At top: Changes over time in the typical silica (SiO2) material of the continents. Garçons work sheds new light on the structure and development of continents over time, making it possible to improve geological models and therefore pave the method for brand-new studies.

Referral: “Episodic development of felsic continents in the past 3.7 Ga” by Marion Garçon, 22 September 2021, Science Advances.DOI: 10.1126/ sciadv.abj1807.

A Billion Years in 40 Seconds Credit: Dr. Andrew Merdith/University of Lyon

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