What does pelite mean?
Pelite is a fine-grained, clay-rich metamorphic rock. It forms when clay-bearing sedimentary materials such as shale or mudstone are altered by heat and pressure, and it is commonly dominated by minerals such as chlorite, mica, and other phyllosilicates. In geological descriptions, pelite may also be used more broadly for a clay-rich rock or sediment, but its principal sense refers to the metamorphic product. The term is useful because it identifies rocks by their mineral and clay-rich character rather than simply by grain size. In the field, pelite can function as a distinctive layer marker, and its presence may help reconstruct the pressure, temperature, and chemical conditions of regional metamorphism.
nounA fine-grained metamorphic rock composed chiefly of clay minerals, especially those formed by the alteration of shale or other argillaceous rocks. Pelite is typically compact and may have a dull, earthy appearance.
- A metamorphic rock rich in clay minerals, typically derived from the metamorphism of shale or mudstone.
- More broadly, a fine-grained, clay-rich rock or sediment characterized by a high proportion of clay minerals.
"The geologist identified the dark band in the cliff as pelite formed by intense pressure on original clay-rich sediment."
"The microscope revealed that the pelite consisted largely of chlorite and white mica."
"Layers of pelite in the valley provide evidence that the region was once part of a sedimentary basin."
The plural is used when referring to multiple pelite bodies, layers, or rock types.
"Several pelites occur along the ridge, separated by quartzite."
Pelite is essentially clay transformed by geological pressure: its name comes from the same Greek root for mud or clay that underlies many earth-science terms.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pelite come from?
The word comes from Greek pēlos, meaning mud or clay, through the combining form pel-. In geological usage, the term developed as a name for a fine-grained, clay-rich metamorphic rock. Its related forms include peloid and peloidal, which belong to the same Greek-root family and refer to clay-rich or clay-like material.
Related word forms
How pelite is actually used
Pelite is primarily a geological term. It is narrower than the general word clay and usually refers to a clay-rich metamorphic rock, although some geological literature uses it more broadly for fine-grained argillaceous material. The associated adjective is pelitic.