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6

The other answer is already pretty good: No plate tectonics and no water erosion allows material to pile up in one place, and then stay put. Neither is the case on earth: The plate moves away from the hot spot, transporting built up rocks with it and causing the magma to find another outlet a few miles over. Hawaii also tends to be a place where you can see ...


47

This is mostly due to the fact that Mars does not have plate tectonics. Therefore the plate stays above the hotspot without moving, allowing magma to rise and pile up at the same place for millions and millions of years. Above the Hawaii hotspot, the oceanic plate is moving, so volcanism tends to drift away with time (actually the volcanism happens at the ...


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Frost leaves a record by damaging the cell structure, creating a "frost ring". Hadd et al discuss data on frost rings in N. American trees. There is specific discussion of the Fimbul event (in AD 536) in this paper by Helama et al. 2019 (unfortunately with a pay wall). There is also discussion that there may have been a similar event in 1627 BC. If ...


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Almost 20 galactic years (each galactic year = 230 million solar years) have passed since birth of our sun, and three galactic years have passed since the remarkable formation of life on Earth when atmospheric oxygen concentration significantly increased (during the time period, we have orbited the Milky Way galaxy three times). Depending on the ...


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As mentioned in a comment to another answer, the terms "basic" and "acid" in relation to igneous rocks are outdated and stem from an incomplete understanding of rock chemistry in the past. Better terms are "ultramafic", "mafic", "felsic", etc. As to your question - why aren't there "ultrafelsic" ...


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