Alkalic Olivine Basalt
Hand Sample: Aphanitic dark gray vesicular basalt. Vesicles are common throughout sample and range in size from 0.1 to 3.5cm in diameter. Individual olivine crystals are found throughout the sample and range in size from 0.1 to 0.4cm in length.
Thin Section: Groundmass dominated by plagioclase, glass and pyroxenes. Large phenocrysts of euhedral to subhedral olivine can be observed throughout the sample in addition to occasional vesicles.
Sample collected in January, 1969.
Western Minerals
HA-28
Alkalic Olivine Basalt
Hand Sample: Aphanitic dark gray vesicular basalt. Sample contains numerous vesicles ranging in size from less than 0.05cm to 1.5cm. Individual olivine crystals can also be found throughout the sample.
Thin Section: Groundmass of medium size plagioclase, pyroxenes, and olivine. Vesicles are numerous throughout the sample.
Sample collected in January, 1969.
Western Minerals
HA-27
Alkalic Olivine Basalt
Hand Sample: Aphanitic light gray vesicular basalt with large olivine crystals. Olivine phenocrysts range in size from single crystals approx. 0.1cm in diameter to clusters of olivine as large as 1cm in diameter. Vesicles throughout the sample are primarily large and also elongate in shape.
Thin Section: Groundmass composed of small sized plagioclase grains, glass, and clinopyroxene. Some small phenocrysts of olivine present throughout the thin section.
Sample collected in January, 1969.
Western Minerals
HA-21
Alkalic Olivine Basalt
Hand Sample: Aphanitic, light gray alkalic olivine basalt. Sample contains abundant feldspar phenocrysts ranging in diameter from 0.1cm to 0.9cm in length. Phenocrysts are generally blocky in shape. Occasional vesicles throughout sample ranging in diameter from 0.05cm to 0.3cm.
Thin Section: Groundmass of plagioclase grains. Large plagioclase and feldspar phenocrysts are abundant throughout sample. Some vesicles present in thin section.
Sample collected January, 1969
Western Minerals
HA-10
Alkalic Olivine Basalt
Hand Sample: Aphanitic, light-gray alkalic olivine basalt. Sample contains abundant phenocrysts of feldspar, olivine, and augite. Phenocrysts range in diameter from 0.1cm to 0.5cm. Many of the phenocrysts in sample have an iridescent luster. Sample has very few vesicles, which are generally less than 0.1cm in diameter.
Thin Section: Groundmass of plagioclase grains. Phenocrysts of plagioclase, olivine and augite are abundant throughout sample.
Sample collected January, 1969
Western Minerals
HA-9