Stock (geology)

In geology, a stock is an igneous intrusion that has a surface exposure of less than 100 square kilometres (40 sq mi),^[1][2] differing from batholiths only in being smaller. A stock has a discordant relationship with the rocks that it intrudes. Many stocks are cupolas of hidden batholiths.^[3][2] Some circular or elliptical stocks may be volcanic plugs, which fill the vents of now extinct volcanoes.^[4][5] A boss is a small stock.^[6]

A stock of nordmarkite (quartz-alkali syenite) of Triassic age, in the Gevanim Valley, Makhtesh Ramon, southern Israel.

Examples

• the Alta and Clayton Peak stocks (composed of granodiorite), near Park City, Utah^[7]
• the Hellroaring Creek and Salal Creek stocks (of granite-granodiorite and quartz monzonite, respectively) in British Columbia, Canada^[8][9]
• the Céret stock (of gabbro and diorite) in Pyrénées-Orientales, France^[10]
• the Parashi stock (of tonalite) in La Guajira Department, Colombia^[11]
• stocks of syenite in the Caldera de Tejeda on Gran Canaria^[12]
• Ailsa Craig granitic boss, which forms a volcanic plug, in Scotland^[5]