pyroxenebearing

Pyroxene-bearing is a term used in geology to describe rocks that contain one or more pyroxene minerals within their mineral assemblage. Pyroxenes are a group of inosilicate minerals characterized by single-chain SiO3 tetrahedra and two cleavage planes typically at about 90 degrees. They commonly occur with feldspar and olivine in mafic and ultramafic rocks and can also be present in metamorphic rocks formed under high temperatures.

The pyroxene group is divided into orthopyroxenes (such as enstatite and pigeonite) and clinopyroxenes (such as diopside and augite). The relative abundance of orthopyroxene versus clinopyroxene, as well as their chemical composition, helps distinguish rock types. Pyroxene-bearing rocks include basalt, diabase (diorite), and gabbro in the igneous family, as well as pyroxenites and certain mantle-derived rocks. In metamorphic rocks, pyroxenes can be stable at high temperatures and pressures, particularly in granulite facies, indicating a high-temperature history.

Identification of pyroxene-bearing rocks relies on mineralogical features such as cleavage and crystal habit. Pyroxenes typically exhibit two good cleavages near 90 degrees and occur as prismatic crystals that range in color from green to brown to black. Clinopyroxene minerals often appear darker with a greenish tint, while orthopyroxenes can be relatively lighter in color.

Significance lies in using pyroxene as a guide to crystallization conditions and tectonic setting. The presence and type of pyroxene help infer magma origin, cooling history, and metamorphic conditions, aiding the reconstruction of geological processes.