Stoping is a process accommodating the ascent of

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...

tic bodies from their sources in the

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

or lower crust to the surface. The theory was independently developed by Canadian geologist

Reginald Aldworth Daly Reginald Aldworth Daly (March 18, 1871 – September 19, 1957) was a Canadian geologist. Biography Reginald Daly was educated at the University of Toronto, where geologist A.P. Coleman persuaded him away from teaching mathematics and into Earth ...

and American geologist Joseph Barrell.1925. ''Biographical Memoir of Joseph Barrell'' by Charles Schuchert
/ref> The process involves the mechanical disintegration of the surrounding

country A country is a distinct part of the world, such as a state, nation, or other political entity. It may be a sovereign state or make up one part of a larger state. For example, the country of Japan is an independent, sovereign state, whi ...

/host rock, typically through fracturing due to pressure increases associated with

thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kin ...

of the host rock in proximity of the interface with the melt. After fractures are formed, melt and/or

volatiles Volatiles are the group of chemical elements and chemical compounds that can be readily vaporized. In contrast with volatiles, elements and compounds that are not readily vaporized are known as refractory substances. On planet Earth, the term ...

will typically invade, widening the fracture and promoting the foundering of host rock blocks (i.e. stoped blocks). Once suspended in the melt, stoped blocks may either sink or float depending upon the

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...

of the block relative to that of the melt. Additionally, blocks submerged within melt are subject to further thermally-induced fracturing which may account for the often observed "lack of evidence" for the process of stoping.

References

Igneous petrology Geological processes {{petrology-stub

See also

References