What is the main structural feature of continents in terms of rock type?

The main structural feature of continents primarily consists of igneous rock. This is significant because the continental crust, which forms the landmasses of the Earth, is predominantly composed of granitic (felsic) igneous rocks. These rocks are less dense than the basaltic rocks that make up the oceanic crust, which is why continents are elevated compared to ocean floors.

Igneous rocks form from the cooling and solidification of molten magma or lava, leading to extensive formations of granitic rocks that make up much of the continental crust. The presence of these rocks is critical in understanding the geological processes that shape continents, including mountain building, volcanic activity, and tectonic movements.

While metamorphic rocks are present in the continental crust, they typically form from the alteration of existing rocks under high pressure and temperature conditions rather than being a primary component. Silicate material refers more broadly to minerals containing silicon and oxygen, which include both igneous and many metamorphic rocks, but it lacks the specificity of identifying the dominant rock type. Dense sedimentary rocks may also be present on the continents, often in basins, but they do not serve as the main structural feature of continental geology.