The Oldest Rock In The World Tells Us A Story
It's hard to imagine how this teeny little rock - it's not even a whole rock, it's just a grain, a miniscule droplet of mineral barely the thickness of a human hair - could rewrite the history of our planet.
Join the discussion below, or Read more at National Public Radio.
“Geologist [I'm Climate Change]”
Since: Mar 07
#1 Jan 14, 2013
I like the bit about the Geothermometer.
The important bit is that the sun was only just formed as a yellow dwarf and was about 50% of its current brightness abd maybe 40%.
The result is that the general environment of Earth was rather cooler than @ present and with shading from dust in the disc, the temperature ambient would likely be below the ice line.
The only heating above the ice line would then come from volcanic outgassing and also incoming bloody great big asteroids.
This Zircon should date past the time of the Earth/Moon formation crash where a global magma ocean existed on the surface of both bodies for a while. The magma ocean would likely have crusted over in a few millennia, and would have thickened enough to form a stable crust in a few million years which would then be thickened by stacks of lava flows from the still fluid part. It should be relatively cool on top of this thick crust above the magma ocean @ that time.
It is likely that this zircon was part of the thick post impact Hadean crust or a lava outpouring on top, which added to the stack growing on it.
have a nice day: Ag
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