lithogeneration

Lithogeneration is a geological term used to describe the generation of lithologies, i.e., rock types, within the Earth's crust and upper mantle. In practice, it refers to the combined set of processes that create and modify rocks, spanning igneous, sedimentary, and metamorphic pathways. Because the term is not universally standardized, it is often used descriptively to discuss crustal rock formation rather than as a precise technical category.

Igneous lithogeneration involves the formation of rocks from molten material. Partial melting of existing rocks, fractional crystallization, and differentiation of magmas generate igneous varieties ranging from felsic to mafic. The cooling and crystallization history, including plutonic versus volcanic emplacement, control mineralogy and texture.

Sedimentary lithogeneration involves weathering, erosion, transport, deposition, and diagenesis that transform preexisting material into sedimentary rocks. Lithification—compaction and cementation—locks the sediment into rock, while diagenetic fluids can alter mineralogy and porosity.

Metamorphic lithogeneration involves alteration of rocks by heat, pressure, and chemically active fluids. Metamorphism can reorganize minerals and create new metamorphic facies, producing rocks such as slate, schist, gneiss, or marble from original rocks.

In crustal evolution, lithogeneration processes interact with tectonics, magma migration, sediment supply, and surface conditions, influencing crust composition and landscape. The term is primarily descriptive; established terms like lithogenesis, rock formation processes, and petrogenesis are more common in technical literature.