Figure 4. Textures in the gabbro. Here, groups of large pyroxene crystals are clumped together in a finer ground mass of light feldspar in a texture geologists refer to as glomeroporphyritic. Olivine is light brown. Note the white rims (feldspar) around some dark green pyroxene crystals. These "reaction rims" indicate that the chemical components of pyroxene and feldspar are interacting. Note that through subsequent geologic processes, the same dark green pyroxenes have been partially altered to lighter green hornblende.
Last updated on May 13, 2010