Volcanic litharenite, Black Sand Beach, Big Island, Hawaii
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Black Beach |
Location:
South shore of Big Island, Hawaii, Black Sand Beach
Provenance:
Volcanic sand of recent basaltic lava: along Hawaii's south coast, basaltic lava, up to 1100 deg C hot, is shock-cooled upon contact with the sea water. Glassy beads and highly porous basaltic "spatter" form which are quickly ground up into shards by shoreline surf and swash. The black beach becomes extremely hot under the morning sun.
Composition:
Dominantly light green volcanic glass, isotropic in polarized light. A few colourful clinopyroxen crystals (maybe olivine as well ?) and a few microlithic VRFs.
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Macroscopic view, line in |
Petrographic thin section:
Basaltic VRFs
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Bright field |
Dark field |
Texture:
Texture of the grains, ecc.
Sample Number:
number of the sample
Collector:
Collector of the sand, Institution
Date:
Date of sampling
Comments:
Further comments on the sand, depositional history, ecc.