eksogeensed

Eksogeensed is a neologism used in speculative planetary science to describe a proposed class of processes whereby external, exogenous geochemical inputs are incorporated into a planet's crust and mantle, leaving detectable signatures in mineralogy and isotopic ratios. The term is formed from exo- (external) and geo- (earth) with a suffix modeled on related terms such as exogenic.

The concept envisions mechanisms such as accretion of meteoritic and cosmic dust, cometary delivery of volatiles, and subsequent integration through weathering, hydrothermal alteration, or mantle-crust exchange, producing geochemical fingerprints that differ from endogenic sources. In these models, eksogeensed signatures could alter the interpretation of a planet’s crustal evolution and mineral resource potential by introducing exogenous material into native geochemical regimes.

In speculative models, eksogeensed signatures could complicate interpretations of isotopic data, mineral deposits, and crustal development on planets and small bodies, and could inform discussions about exoplanetary geology by identifying external influences that shape surface and near-surface composition. The idea is frequently explored in thought experiments and in science fiction as a framework for considering how non-native inputs might interact with planetary geologies over various timescales.

The term lacks broad acceptance in mainstream geoscience and is primarily encountered in speculative discussions. Critics argue that many features attributed to eksogeensed processes can be explained by established exogenic inputs and endogenic geochemical evolution, without invoking a distinct, separable mechanism.

See also: exogeology, cosmochemistry, meteoritics, planetary geology.