diapir

plural diapirs

1. geographyAn intrusion of a ductile rock into an overburden.

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

   29 April 1989, Nigel Henbest, “Geologists hit back at impact theory of extinctions”, in New Scientist

   2 more examples

   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.

   1994, Peter Olson, “Mechanics of Flood Basalt Magmatism”, in Michael P. Ryan, editor, Magmatic Systems, Academic Press, →ISBN, page 12

   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.

   2004, Richard Fortey, The Earth: An Intimate History, HarperCollins, published 2010, →ISBN, page unnumbered page