geosphere

The geosphere, or sometimes the solid Earth, denotes the planet's rigid, nonbiological portion. It includes the crust, both continental and oceanic, the mantle, and the core (outer liquid and inner solid). It encompasses the rocks, minerals, soils, and the internal structure that underlies the surface. As one of the Earth's major subsystems, the geosphere interacts with the hydrosphere, atmosphere, and biosphere to shape landscapes and to supply resources and nutrients.

The crust forms the outer skin: granitic continents and basaltic ocean floors. The mantle lies beneath the crust, divided into the rigid upper mantle and the more ductile lower mantle; the asthenosphere, part of the upper mantle, allows tectonic plate motion. The core consists of a liquid iron-nickel outer core and a solid inner core and generates Earth's magnetic field.

Geologic processes in the geosphere include plate tectonics, volcanism, magmatic differentiation, mountain building, weathering, erosion, sedimentation, and isostatic adjustments. Heat flow from the interior drives convection in the mantle and fuels magmatic activity. The geosphere continuously evolves through cycles of deformation, melting, crystallization, uplift, and subsidence.

Humans rely on the geosphere for resources and landforms, while geologic hazards such as earthquakes, landslides, and volcanic eruptions pose risks. Scientific study of the geosphere uses geology, geophysics, geochemistry, and geomorphology to understand past and present processes and to model future change.