![]() A rock that contains over 90% mafic minerals is classed as an ultramafic rock. Gabbros are classified as leucogabbro, which includes less than 35% mafic minerals, meso gabbros, which contain 35 to 65% mafic minerals, and melagabbros, which contain over 65 percent mafic minerals. Geologists have identified several subtypes of gabbro. Hornblende usually appears as a ring around augite crystals or as giant grains surrounding smaller grains of other minerals when it is present. Pyroxene and calcium-rich plagioclase make up gabbro, along with hornblende, olivine, and other minor minerals. He coined the term 'gabbro' to describe rocks that geologists today refer to as 'metagabbro'. The word was first employed more restrictively in 1809 by German geologist Christian Leopold von Buch in his description of these Italian ophiolitic rocks. ![]() Gabbro, a hamlet near Rosignano Marittimo in Tuscany, was the inspiration for the name. In the 1760s, the term 'gabbro' was coined to describe a group of rock types found in the Apennine Mountains' ophiolites. Today we will discuss one such intrusive igneous rock called ‘gabbro’. Some of the magma may fuel volcanoes on the surface, but the majority is confined beneath the surface, where it cools slowly over decades or millions of years before solidifying. Molten rock in large globs rises to the surface. When magma is imprisoned deep within the earth, intrusive, or plutonic, igneous rock occurs. Depending on where the molten rock hardens, igneous rocks are classified as intrusive or extrusive. The melt starts deep under the earth, around active plate borders or hot regions, and then rises to the surface. When a molten rock crystallizes and solidifies, igneous rocks form. ![]() In this post, we reveal everything you need to know about gabbro, including its meaning, colors, and uses.
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