Oldest-ever igneous meteorite contains clues to planet building blocks

Scientists believe the solar system was formed some 4.6 billion years ago when a cloud of gas and dust collapsed under gravity possibly triggered by a cataclysmic explosion from a nearby massive star or supernova. As this cloud collapsed, it formed a spinning disk with the sun in the center. Since then scientists have been able to establish the formation of the solar system piece by piece.

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Thanks for reminding us that not all science involves life. The article is open access https://www.nature.com/articles/s41467-018-05501-0 . Just my 2 cents from a quick read.

Fig 3a shows composition of extrusive igneous rocks (those that cool at Earth’s surface). Basalt is oceanic crust (high Fe and Mg) and rhyolite (low Fe & Mg and high silica and feldspar) is basically granitic composition. The point being, from a Geol 101 perspective, when basaltic crust subducts beneath granitic crust the resulting melt is a mix of the two and called Andesite (from the type location in the Andes Mountains). This implies significant plate tectonic history and not to be expected in the early solar system and requires water. The authors are clear that given other geochemical signals the achondritic material studied in the paper is most likely due to some as yet unknown low pressure-high temperature process due to the presence of trydimite.

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On this same kind of subject, this is a good (albeit pretty old) review article explaining how we know what we know about the Earth’s core, including the elemental composition. Data from meteorites, seismology, geodesy, etc is leveraged to paint a picture of the Earth far below our feet. Quite remarkable.

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