Metagabbro

Metagabbro is a metamorphic rock formed from the metamorphism of gabbro. Gabbro, a coarse-grained, intrusive igneous rock, transforms under intense heat, pressure, and sometimes the addition of chemically active fluids, leading to recrystallization and the development of new minerals. This metamorphic process alters the original mineral composition and texture of the gabbro. The resulting metagabbro exhibits textures ranging from massive to foliated, depending on the intensity and nature of the metamorphic forces. The mineral assemblage often includes amphiboles (such as hornblende), plagioclase feldspar, garnet, epidote, and occasionally pyroxene relics. The specific mineralogy reflects the protolith's original composition and the metamorphic grade experienced. Metagabbros are valuable in understanding regional metamorphic histories and provide insights into the geological processes occurring deep within the Earth's crust.

Metagabbro meaning with examples

• Geologists studying the exposed metagabbro outcrops in the Scottish Highlands found evidence of intense deformation and high-grade metamorphism, indicating collision events. The textural changes in the metagabbro provided clues about the stress regimes affecting the area. Mineral analysis confirmed the presence of garnet and amphibole, suggesting significant temperatures and pressures.
• The mapping project revealed a band of metagabbro, tracing its origin to an ancient intrusion now found in the metamorphosed core of a mountain belt. Scientists used geochronology of the metagabbro to determine the age of the original gabbro, and the timing of metamorphic overprint. The presence of pseudomorphic textures indicated incomplete alteration.
• The exploration team drilled through layers of metagabbro seeking to assess the potential of finding metallic ore deposits. The metagabbro's mineral content, and trace element analysis of the newly found minerals were used to constrain its evolution. The presence of hydrous minerals in the metagabbro suggested interaction with water rich fluids.
• Researchers analyzed the isotopic composition of oxygen and strontium within a sample of metagabbro. These isotope ratios helped reconstruct the fluid-rock interaction, and the overall geothermal gradient within this rock. The study aimed to constrain the metamorphic conditions the metagabbro had experienced from magmatic cooling.
• The structural geology team noted that the metagabbro layer showed evidence of folding and faulting, further complicated by intense metamorphism. The orientation of newly formed minerals within the metagabbro gave vital information about the direction of stress during regional compression. This revealed much about its history.