Crustaalisen

Crustaalisen is the Finnish adjective used to describe phenomena, rocks, and processes related to the crust of a planetary body, most often the Earth's. In geology and geophysics, it denotes anything pertaining to the outermost solid shell that lies above the mantle.

Earth's crust comprises two major types: continental crust, which is thick and granitic in composition; and oceanic crust, which is thinner and basaltic. Continental crust averages about 30-50 kilometers thick and can exceed 70 kilometers in mountain regions, while oceanic crust is roughly 5-10 kilometers thick. The crust rests on the mantle as part of the lithosphere. Crustal rocks control much of the surface environment, including soil formation, mineral resources, and topography.

Crustal geology and tectonics involve deformation, faulting, subduction, collision, and magmatic addition. Crustal growth occurs through accretion and magmatic differentiation; crustal recycling happens in subduction zones where crust is melted and returned to the mantle. The distribution and properties of the crust influence seismic activity, mountain building, and volcanic processes.

Study methods include seismology (refraction and tomography), gravity and magnetic surveys, and radiometric dating; geochemical analysis helps reveal crustal composition and age. Global crustal models, such as CRUST1.0, provide thickness and velocity information used in tectonic research and resource exploration.

Planetary crusts on bodies other than Earth show diverse compositions and histories. The Moon’s crust is rich in anorthosite material, Mars hosts extensive basaltic crust, and the large-scale crustal dichotomy on Mars reflects early crust formation and resurfacing.