intrusiohavaintojärjestelmiä

Intrusiohavainto is a term used in geology to describe observations of igneous intrusions—magma that crystallizes below the Earth's surface as intrusive bodies such as dikes, sills, and plutons. The term combines the Finnish roots intrusio- (intrusion) and havainto (observation).

Intrusive rocks form when magma is trapped within crustal rocks, cooling slowly and producing coarse-grained textures. Observations emphasize the geometry of intrusions, contact relationships with surrounding rocks, and cross-cutting features that reveal the sequence of events during intrusion and cooling.

Field mapping, petrographic analysis, and geochronology are common methods for studying intrusiohavainto. Radiometric dating (for example U-Pb and K-Ar methods) constrains emplacement ages, while geophysical surveys (magnetic, gravity) help infer subsurface geometry when direct exposure is limited.

Understanding intrusiohavainto contributes to models of crustal evolution, ore formation through contact metamorphism and hydrothermal systems, and mineral resource exploration. It also provides insights into tectonic settings and magma differentiation processes that shape continental crust.

See also: intrusion (geology); dyke; sill; pluton; contact metamorphism; geochronology.