Rock collected below the solidus of 990 degree C. Makaopuhi Lava Lake, Hawaii. n.d.
Crystallization of basalt in Makaopuhi lava lake, Hawaii
Summary
The area shown in each slide is approximately 0.9 x 1.2 mm. Olivine phenocrysts are as much as 2 mm in longest dimension, but average close to 0.5 mm. Clinopyroxene crystals are small and equant, rarely exceeding 0.1 mm in length and close to 0.01 mm in their short dimension. Slide 6 shows a rock collected below the solidus of 990 degree C. Not easily seen in the slide (but evident under a high power microscope objective) are small pools of clear glass that is retained metastably below the solidus. The decrease in intensity of the color of the glass going from slide 4 to slide 6 is caused by a decrease in abundance of iron and titanium, which are taken up in the opaque phases. The large olivine phenocryst that dominates this [...]
Summary
The area shown in each slide is approximately 0.9 x 1.2 mm. Olivine phenocrysts are as much as 2 mm in longest dimension, but average close to 0.5 mm. Clinopyroxene crystals are small and equant, rarely exceeding 0.1 mm in length and close to 0.01 mm in their short dimension.
Slide 6 shows a rock collected below the solidus of 990 degree C. Not easily seen in the slide (but evident under a high power microscope objective) are small pools of clear glass that is retained metastably below the solidus. The decrease in intensity of the color of the glass going from slide 4 to slide 6 is caused by a decrease in abundance of iron and titanium, which are taken up in the opaque phases. The large olivine phenocryst that dominates this slide is fractures and resorbed (compared with slide 1) but is not altered.
Published as Slide 6 in U.S. Geological Survey publication titled, "Crystallization of basalt in Makaopuhi lava lake, Hawaii: descriptive material to accompany of set of 7 colored slides illustrating "Crystallization of basalt in Makaopuhi lava lake, Hawaii".
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Available in the USGS Denver Library Photographic Collection, 2017 DENPH00002, Wright, Thomas L. digital collection (all images are jpegs).
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