Rocks produced by the cooling of magma or lava and classified by composition and texture are called

Rocks produced by the cooling of magma or lava and classified by composition and texture are called

• A. Sedimentary
• B. Clastic
• C. Metamorphic
• D. Igneous

Answer: (D)

Rocks formed from cooling molten material are igneous rocks. They originate when magma underground or lava at the surface crystallizes and hardens, giving us a fire-born family of rocks. The texture depends on cooling rate: slow cooling inside the crust produces coarse crystals (like granite), rapid cooling at the surface yields fine crystals (like basalt), and very rapid cooling can create glassy rocks (like obsidian). Compositionally, igneous rocks range from felsic to mafic to ultramafic, with felsic rocks being lighter and silica-rich and mafic rocks darker and richer in iron and magnesium. This distinguishes them from sedimentary rocks, which form from deposited and cemented sediments, and metamorphic rocks, which form from existing rocks altered by heat and pressure. Clastic refers to a texture of sedimentary rocks made of fragments, not to rocks formed by cooling molten material.

Rocks formed from cooling molten material are igneous rocks. They originate when magma underground or lava at the surface crystallizes and hardens, giving us a fire-born family of rocks. The texture depends on cooling rate: slow cooling inside the crust produces coarse crystals (like granite), rapid cooling at the surface yields fine crystals (like basalt), and very rapid cooling can create glassy rocks (like obsidian). Compositionally, igneous rocks range from felsic to mafic to ultramafic, with felsic rocks being lighter and silica-rich and mafic rocks darker and richer in iron and magnesium. This distinguishes them from sedimentary rocks, which form from deposited and cemented sediments, and metamorphic rocks, which form from existing rocks altered by heat and pressure. Clastic refers to a texture of sedimentary rocks made of fragments, not to rocks formed by cooling molten material.