What in Hades?
If ever there is war in heaven , the armorers will head for the stockroom in search of bars of samarium 147. Because while nowhere near as strong or keen as steel, weapons forged from it are guaranteed to last- the rare earth metal has a half life of 106 billion years, about eight times the age of the known universe.
This factoid is good for more than tweaking the noses of those who take the works of John Milton literally , or base their chronology on the Begats in Genesis. Samarium 147 has a companion isotope , Sm146, with a half life a thousand times shorter , and science has used the two to forge the tools for dating the oldest rocks on Earth.
The oldest rocks we know, which originally crystallized about 3,850,000 years ago , making them less than a billion years younger than the solar system itself, come from near the oldest Viking settlements in the New World, in Southwest Greenland, edging out those from western Australia by a hundred million years or so. Both date to a geological epoch when the Earth was indeed void and without form.
3.85 Giga-Years ago, most of it was still bloody molten, with the first solid rock just beginning to solidify , lumps left from the earth's nebular coalescence still underfoot, and protocontinental islets bobbing about like incandescent icebergs in a frequently asteroid-blasted magma ocean . Some think they rafted together like white-hot pack ice into the first masses of something resembling land, under conditions so hellish that this first and worst of times on planet Earth is called "The Hadean Era"
Things are a thousand degrees or so cooler now, but as climate has regained a degree in the last century, glacial retreat in Greenland has yielded better access to a wider variety of the oldest rocks . These are beginning to shed light on a very basic qustion- how sell stirred was this hellish cauldron ?
In Science (21 December 2007: Vol. 318. no. 5858, pp. 1907 - 1910) Vickie C. Bennett, Alan D. Brandon, and Allen P. Nutman report on two rare earth element isotopes resulting from samarium decay in the the oldest rocks. It appears there is a coupled excess of neodymium-142 excesses (from decay of now-extinct samarium-146; half-life, 103 million years) and neodymium-143 excesses (from decay of samarium-147; half-life, 106 billion years), relative to chondritic meteorites, that distinctively date the formation of silicate magma reservoirs in the Earth's first 30 million to 75 million years.
This differs enough from the oldest rocks in Australia to reveal that despite the high temperatures and all the pummeling by asteroid impacts, the primordial lumpiness of the early Earth's mantle persisted for at least the first billion years of Earth history:" Temporal variations in 142Nd signatures track the incomplete remixing of ...domains formed in the Hadean mantle."
It should take the usual idiotarians less than an eon to proclaim that all this really means is that Greenland is not so hot after all, and that any warming there is the devils work and not an act of God or man.