Macro view of Picritic Basalt

SIA2141: Macro view of Picritic Basalt

Photographer:	Calvin J. Hamilton
Copyright:	© 2006 Calvin J. Hamilton
Date Added:	2006/12/30
Location:	Hawaii

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Basalt

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Image Name	Width x Height	Size
SIA2141.jpg	640 x 441	102K
SIA2141.jpg	1200 x 827	284K
SIA2141.jpg	3504 x 2416	1M

Caption

This sample of picritic basalt was made at a high temperature of 1200°C (2200°F) about 2 miles underground in the magma chamber of the Ko'olau volcano. The high temperature allowed the large olivine crystals to form. The crystals grew very slowly for years while underground. The blade-like black and white plagioclase crystals formed during and shortly after the eruption of the magma. The rock dates to 2.5 million years ago.