Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: rocky15_nf on 09/04/2012 19:44:48
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I found this rock on a beach about 25 years ago. There were two this one and another smaller one but i have lost it over the years. It is not the type of rock around those parts. I have always thought that it was some sort of meteor. It does float. I live in Newfoundland Canada and have never seen anything else like this until last week when my brother dragged one up in a scallop drag in another area. Do anyone have any idea what this is.
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(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.thenakedscientists.com%2Fforum%2Findex.php%3Faction%3Ddlattach%3Btopic%3D43777.0%3Battach%3D16282%3Bimage&hash=64ef4a7c615bfa1b5e8dd17d090c7af7)
aero (http://thelandthatuglyforgot.com/tag/aero/) vesicular basalt ? ...
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww4.uwm.edu%2Fcourse%2F422-100%2FMineral_Rocks%2Fvesicular.basalt1.jpg&hash=5951b067f2064e915d73830385057c34)
http://media.hcpss.org/newcode/ekits/ekits.php?eKitID=172
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Thanks for your help now i know its not out of this world, lol.Just dont know how it got here as there are no volcanoes around here.
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Just dont know how it got here as there are no volcanoes around here.
It does float.
https://en.wikipedia.org/wiki/Rubber_duck_armada
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It is reasonably safe to call it pumice.
I am not certain that it is possible to be so specfic as to call it vesicular basalt (although it could be) just from a photograph. If I remember right, pumice tends to be produced from more felsic rather than basaltic eruptions (which would also accord with the light colour)
Pumice has been seen in "rafts" that have floated around for years.
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I dont know much about this, does pumice also come from volcanoes.
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Yes, "pumice" comes from volcanos. It is actually a description of the texture of the rock rather than a description of the minerals in the rock*. The holes (or "vesicles") are created by gases disolved in the hot lava and when it erupts the pressure keeping them disovled is relieved so it bubbles out. (A bit like opening a bottle of lemonade) At the same time, the lava is cooling rapidly and the volcanic "froth" is frozen into pumice.
Not all volcanos produce pumice - it depends on a number of factors including chemical composition of the lava and the amount of water and carbon dioxide in the mix.
*Some rocks are described by what they contain (for example granite contains quartz, mica and feldspar) others by the grain size - siltstone, sandstone and gritstone are all mainly quartz, but appear quite different and some by texture - such as pumice and porphyry.
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thanks for the info.