Lopolith
Also called: Lapolith · Topic: Interior of the Earth: Earthquakes, Volcanoes and the Layered Earth · NCERT: Class 11, Ch 3 "Interior of the Earth"
Meaning
A lopolith is a saucer-shaped mass of igneous rock that formed inside the crust. Its middle dips down, so it is concave to the sky (hollow when seen from above). It forms when rising magma spreads sideways along a weak plane between rock layers. The heavy mass then sags in the middle. NCERT spells it "lapolith". A lopolith is an intrusive landform. This means it cooled underground and shows at the surface only after erosion.
Example
The Bushveld complex in South Africa is a famous lopolith. It is rich in platinum and chromium.
Don't confuse with
- Laccolith: arches upwards into a dome with a flat base. A lopolith sags downwards like a saucer.
- Sill: a flat, roughly horizontal sheet between rock layers. It does not sag into a saucer shape.