The "bell jar" type of these are special cases of the bysmalith type, and dedimentary ones may develop when excessive lithostatic pressure allows fluid pressure to rise high enough to crack a stratum of rock and carry sediment up the crack.
The Noril's-Talnakh type of these structures are ultramafic examples thought to have been created by plume magmatism. The "bell jar" type of these are special cases of the bysmalith type, and dedimentary ones may develop when excessive lithostatic pressure allows fluid pressure to rise high enough to crack a stratum of rock and carry sediment up the crack. Especially large ones are frequently called batholiths, but the best known varieties are mostly vertical and mostly horizontal, called, respectively, dikes and sills. For 10 points, give the term that usually denotes a formation of crystallized magma underground, a deposit of plutonic igneous rock.
The Noril's-Talnakh type of these structures are ultramafic examples thought to have been created by plume magmatism.
intrusions