Science Fair Project Encyclopedia
Accretionary lapilli
Rounded tephra balls between 2 and 64 mm in diameter are called accretionary lapilli if they consist of tiny volcanic ash particles. Volcanic ash sometimes form such balls in an eruption column or cloud, owing to moisture or electrostatic forces. Lapilli (singular: lapillus) means "little stones" in Italian. Acretionary lapilli are like volcanic hailstones that form by the addition of concentric layers of moist ash around a central nucleus.
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10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details