Noun

(en noun)

The forcible inclusion or entry of an external group or individual; the act of intruding.

* He viewed sales calls as an unwelcome intrusion .

*{{quote-magazine, date=2012-12-14

, author=Simon Jenkins, authorlink=Simon Jenkins , title=We mustn't overreact to North Korea boys' toys , volume=188, issue=2, page=23 , date=2012-12-21 , magazine= citation , passage=The threat of terrorism to the British lies in the overreaction to it of British governments. Each one in turn clicks up the ratchet of surveillance, intrusion and security. Each one diminishes liberty.}}

(geology) Magma forced into other rock formations; the rock formed when such magma solidifies.

Noun

(en noun)

(geology) An intrusion of a ductile rock into an overburden.

* 1989 , Nigel Henbest, " Geologists hit back at impact theory of extinctions", New Scientist , 29 April 1989:

"If a diapir is outside an established plume it rises at a much slower rate," Loper says.

* 1994 , Peter Olson, "Mechanics of Flood Basalt Magmatism", in Magmatic Systems (ed. Michael P. Ryan), Academic Press (1994), ISBN 0126050708, page 12:

This final stage is characterized by the cooling and resolidification of the partially molten diapir within the mantle, slow subsidence at the surface, and greatly diminished rates of crustal addition.

* 2004 , (Richard Fortey), The Earth: An Intimate History , HarperCollins (2010), ISBN 9780007373338, unnumbered page:

Deeply buried deposits of sea-salt dome upwards and pass through the overlying strata, as a kind of intrusive lobe, eventually emerging at the surface – the rising tongue is called a diapir .