(d) Ross Mitchell
Jack Hills zircon is about 200 microns in diameter.
The world’s oldest crystals, discovered in Australia’s Jack Hills, contain remnants of older rocks – some of which have been reprocessed by magma into surviving crystals.
It was with the help of Machine learning Geologists have discovered that a third of these primitive rocks were SedimentaryThis fact means that more than four billion years ago, the Earth had an extensive crust exposed to the elements above sea level.
Basically, as he explained, IFL ScienceThe atoms on Earth are, for the most part, the same atoms that were here more than four billion years ago, even though no solid elements are alive. Everything has been reprocessed.
Zircon Jack Hills is oldest surviving monuments From Earth. It was formed 4.4 billion years ago, and then incorporated into sedimentary rocks that have since given way to erosion, leaving only zircon.
These zircons crystallized from magma, but not from the original. This magma was made from ancient rocks that were pulled down to the Earth to melt, and most of the information about these rocks was lost as the magma was reprocessed.
In this study, geologists hope to discover whether any of these rocks exist. Sedimentary Or if they were all My fire.
Igneous rocks can form from the cooling of magma or lava that we know existed on early Earth, but sedimentary rocks require a water cycle. Rain erodes them and the material is washed into lakes or oceans to be deposited and transformed into new forms of rock.
By training computers to recognize the fingerprints of sedimentary materials within zircon, the researchers were able to determine that a sample of very old zircon contained a lot of Granite type SGranite that is formed from sediments that have sunk into magma.
The proportion of S-type granite increases over time, as expected. However, if the method the team used to identify S-type granite is correct, the zircons that formed 4.24 billion years ago are made of 35% S type graniteBasically, instead of increasing forever, the proportion of type S It increases and decreases according to the cycles of formation and collapse of supercontinents..
Hey Scientific material With the discoveries published in Proceedings of the National Academy of Sciences.
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