groundmass
Noun (Geology): The fine-grained, crystalline material that forms the main mass of a porphyritic rock, within which larger, distinct crystals (phenocrysts) are embedded.
The term "groundmass" is used specifically in geology to describe the background material of an igneous rock. It is the continuous, finer-grained substance that surrounds and supports the larger, visible crystals. * The groundmass of this basalt is composed of microscopic crystals of plagioclase and pyroxene. * In a porphyry, the contrast between the large phenocrysts and the fine-grained groundmass is easily visible.
- The texture and mineral composition of the groundmass are critical for classifying igneous rocks and understanding their cooling history. A glassy groundmass indicates very rapid cooling, while a crystalline one indicates slower cooling.
- Petrologists analyze the groundmass under a microscope to determine the rock's full mineralogy.
- Matrix: A more general term in geology for the fine-grained material enclosing larger grains or crystals in any rock type (sedimentary, metamorphic, or igneous). "Groundmass" is essentially the matrix of an igneous porphyritic rock.
- Matrix (in the specific context of igneous rocks)
The word "groundmass" is a technical term with only this specific geological meaning. It is not used in everyday language.
-
(geology) the matrix of fine-grained crystalline material in which larger crystals are embedded
Khám phá thêm
Các từ liên quan
Từ có nhắc đến "groundmass"
