peridotiterich

Peridotiterich is a geological descriptor for rock units or mantle domains in which peridotite components dominate the mineralogy, particularly olivine and pyroxene. Peridotite is an ultramafic rock, so a peridotiterich body is characterized by a high proportion of these minerals relative to surrounding lithologies such as basalt or gabbro. The term is formed from peridotite plus the suffix rich and is used informally to indicate mantle-like composition within a broader tectonic setting. It is not part of formal stratigraphic nomenclature.

Geologic context: Peridotiterich assemblages are most often noted in ophiolites, mantle xenolith suites carried by basaltic magmas, and ultramafic bodies in subduction or collision zones. They may mark portions of the mantle wedge or subcontinental lithospheric mantle that have retained substantial peridotite content despite partial melting or tectonic processing.

Mineralogy and texture: The mineralogy is dominated by olivine and pyroxenes, with limited plagioclase or feldspathic minerals. Textures range from coarse, granular to harzburgitic or dunitic in alignment with mantle crystallization histories and possible metasomatic alteration such as serpentinization.

Formation and significance: Peridotiterich zones can form through mantle upwelling, tectonic extrusion, or preservation of high-peridotite residues after melting. Studying them helps constrain mantle composition, melting dynamics, and tectonic evolution. Because the term is informal, precise modal definitions and contexts should accompany its use.

See also: peridotite, ultramafic rock, ophiolite, mantle xenolith.