What does batholith mean?
A batholith is a truly enormous body of intrusive igneous rock — most commonly granite — that crystallised from magma deep within the Earth's crust. Unlike lava that erupts at the surface, the magma forming a batholith cools slowly underground, allowing large mineral crystals to develop. Geologists reserve the term for the biggest such masses, generally those exposed over more than about 100 square kilometres; smaller bodies are called stocks or other types of plutons. Because batholiths form at depth, we only see them where uplift and erosion have stripped away the rocks above, leaving vast expanses of granitic terrain such as those underlying the Sierra Nevada or much of Yosemite National Park. The word comes from the Greek roots for 'depth' and 'stone'. It appears almost exclusively in scientific, academic, and popular earth-science contexts, and its scale makes it central to understanding how mountain ranges are built.
nounA very large mass of intrusive igneous rock, typically granite, that formed deep beneath the Earth's surface from cooled magma and may extend over thousands of square kilometres.
- A large mass of intrusive igneous rock, usually granitic, formed by the slow cooling of magma at great depth and often exposed by erosion over broad areas of the crust.
"The Sierra Nevada is underlain by an immense batholith of granitic rock."
"Geologists mapped the Coast Plutonic Complex as a chain of coalescing batholiths along British Columbia's coast."
"Erosion eventually stripped away the overlying rock, revealing the granite batholith at the surface."
Standard regular plural; used when referring to multiple distinct intrusive bodies.
"Several batholiths underlie the mountain belts of western North America."
Batholiths are so vast they can form entire mountain ranges — the Idaho Batholith alone covers more than 40,000 square kilometres.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of batholith
Batholith was coined in the late nineteenth century by the German geologist Carl Wilhelm von Gümbel, combining the Greek 'bathos' (depth) with 'lithos' (stone) to describe these deep-seated rock masses. The term entered English geological usage through translations of European scientific work and became standard as field geology matured. It shares its '-lith' element with related coinages such as monolith, megalith, and laccolith, all drawing on the same Greek root for stone.
Related word forms
How batholith is actually used
A technical term used chiefly in geology and earth-science writing; rare in everyday speech. By convention, bodies of intrusive igneous rock smaller than about 100 square kilometres are classified as stocks rather than batholiths.
Easily confused with batholith
A laccolith is a relatively small, dome-shaped intrusion that arches overlying rock layers, whereas a batholith is a vast, deep-reaching mass of igneous rock.
A pluton is the general term for any body of intrusive igneous rock; a batholith is specifically a very large pluton exceeding roughly 100 square kilometres in surface area.