Intrusive rock

Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions, such as batholiths, dikes, sills, laccoliths, and volcanic necks.However, dikes of basaltic composition often show grain sizes intermediate between plutonic and volcanic rock, and are classified as diabases or dolerites.Rare ultramafic hypabyssal rocks called lamprophyres have their own classification scheme.These differences show the influence of the physical conditions under which crystallization takes place.[13] Intrusions vary widely, from mountain-range-sized batholiths to thin veinlike fracture fillings of aplite or pegmatite.
QAPF diagram for the classification of plutonic rocks
Devils Tower , United States, an igneous intrusion exposed when the surrounding softer rock eroded away
An intrusion (pink Notch Peak monzonite ) inter-fingers (partly as a dike ) with highly metamorphosed black-and-white-striped host rock ( Cambrian carbonate rocks ) near Notch Peak, House Range , Utah , United States
Diagram showing various types of igneous intrusion
Dark dikes intruded into the country rock , Baranof Island , Alaska , United States
QAPF diagramDevils Towerintrusionsbatholithslaccolithsvolcanic necksigneous rockextrusionvolcanic eruptionplanetEarth's cruststockssubvolcanic or hypabyssal rockcountry rockphaneriticsubvolcanicmineralquartzalkali feldsparplagioclasefeldspathoidDioriticgabbroicsodiummagnesiumolivinehornblendeclinopyroxeneultramafic rockscarbonatitebasalticdiabaseslamprophyresNotch PeakmonzoniteCambriancarbonate rocksHouse RangecrystalcavitiesequigranularporphyriticidiomorphicxenomorphicorthoclasesanidinenephelineLeuciteMuscoviteextrusivevitreousvesicularpetrologicallyIgneous intrusionveinlikefractureaplitepegmatiteBaranof IslandAlaskaBatholithChonolithCupolaLaccolithLopolithPhacolithanticlinesynclineVolcanic pipevolcanic neckvolcanoEllicott City GranodioriteGuilford Quartz MonzonitePluton emplacementNorbeck Intrusive SuiteSubvolcanic rockTuolumne Intrusive SuiteVolcanic rockWoodstock Quartz MonzoniteWayback MachineBibcodeCiteSeerXpublic domainChisholm, HughEncyclopædia Britannica GeologicStratigraphic principlesPrinciple of original horizontalityLaw of superpositionPrinciple of lateral continuityPrinciple of cross-cutting relationshipsPrinciple of faunal successionPrinciple of inclusions and componentsWalther's lawPetrologic principlesVolcanicExfoliationWeatheringSoil formationDiagenesisCompactionMetamorphismGeomorphologic processesPlate tectonicsSalt tectonicsTectonic upliftSubsidenceMarine transgressionMarine regressionSediment transportFluvial processesAeolian processesGlacial processesMass wasting processes