A Geoscience Digital Image Library

TitleThin section of hornblende gabbro
DescriptionThis is a cross polarized thin section of hornblende gabbro. An equiangular rock consisting of subhedral labradorite tablets and somewhat subordinate mafics augite, hornblende, magnetite in anhedral clustered grains. The plagioclase shows narrow marginal zoning. The augite is strongly uralitized by olive green hornblende. The opaques are an intergrowth of predominant granular magnetite and subordinate pyrite. Other accessories are biotite, apatite, and chlorite, the last replacing hornblende.
Geologic provinceSan Marcos Gabbro
LocationUSA ▹ California ▹ San Diego. Near Escondido.
PhotographerDarla Sondrol. 2002-04-09.
CollectionWard’s Collection of Classic North American Rocks #28.
Key wordshornblende gabbro, hornblende, gabbro, California, thin section
Tech details2.31 MB. Thin section. Nikon FDX-35.
GeoDIL number2636