Lamprophyre

A lamprophyre is a distinctive group of generally porphyritic, dark-colored, and often altered igneous rocks. They are characterized by the presence of abundant, typically euhedral, mafic minerals (rich in magnesium and iron), often amphibole or biotite, set within a fine-grained groundmass. Lamprophyres usually occur as dikes, sills, or small intrusions and are commonly associated with larger, more felsic intrusions. They are enriched in volatile components, like water and carbon dioxide, and may contain unusual trace elements. Their formation is linked to mantle processes, often involving small-degree partial melting and rapid ascent to shallow crustal levels.

Lamprophyre meaning with examples

• During a geological survey, the team discovered a dark-colored dike. Further analysis revealed the presence of abundant biotite and amphibole crystals, confirming its classification as a lamprophyre. Its unique mineralogy provided insight into the magmatic processes. The rock's altered appearance suggested the presence of volatile components and a rapid cooling rate.
• The geologist examined the exposed rock face, identifying the porphyritic texture of the dark-colored lamprophyre. The large, distinct crystals of olivine, encased in the fine-grained groundmass, caught her eye. The presence of these minerals and its intrusion into the surrounding granite indicated a complex geological history and helped date the regional tectonic activity.
• The exploration drill hit a previously unknown lamprophyre formation. The core sample revealed the characteristic dark color, and detailed analysis confirmed the presence of phlogopite and titanaugite, which are typical components. The discovery provided new data, further confirming the complex geological structure of the area and the local mineral distribution.
• In studying the geochemical signatures of the region, a lamprophyre was identified. Its unusual trace element composition and high volatile content indicated a source from the upper mantle. The lamprophyre's study contributed to a better understanding of the mantle melting processes and regional magmatic evolution and provided evidence of past volcanic activity.