Final Answer:
Igneous rocks like gabbro, basalt, and peridotite form rapidly in volcanic settings, influencing mineral composition.
c) In volcanic settings with rapid cooling.
Step-by-step explanation:
Igneous rocks, including gabbro, basalt, and peridotite, form from molten material that cools and solidifies. The specific environment of formation for these rocks is volcanic settings with rapid cooling. In such environments, molten rock, or magma, erupts from the Earth's interior onto the surface as lava. The rapid exposure to cooler surface conditions causes the magma to solidify quickly, resulting in the formation of fine-grained igneous rocks like basalt.
Gabbro, a coarse-grained rock, also forms in volcanic settings but from a slower-cooling magma beneath the Earth's surface. Peridotite, on the other hand, originates from the upper mantle and is brought to the surface through processes like mantle plume upwelling. The rapid cooling in volcanic environments influences mineral crystallization. For instance, basalt typically contains minerals like plagioclase feldspar, pyroxene, and olivine, while gabbro, having a coarser texture, may exhibit larger crystals of the same minerals. Peridotite, originating from the mantle, contains minerals such as olivine, pyroxene, and, in some cases, garnet.
Understanding the environmental context of igneous rock formation is crucial in deciphering Earth's geological history and processes. The unique mineral compositions of gabbro, basalt, and peridotite, as influenced by the rapid cooling in volcanic settings, provide valuable insights into the Earth's dynamic processes and the conditions under which these rocks solidify.