11th Geography NCERT Chapter 3

Batholiths are large granitic bodies that develop in the deeper depth of the crust and appear on the surface after denudational processes remove the overlying materials. They are the cooled portion of magma chambers.

Lacoliths are large dome-shaped intrusive bodies with a level base and connected by a pipe-like conduit from below. They occur at deeper depths and are localized sources of lava finding its way to the surface. The Karnataka plateau contains examples of lacoliths or batholiths.

Lapoliths are saucer-shaped intrusive bodies, phacoliths are wavy masses of intrusive rocks found at the base of synclines or at the top of anticlines, and sills are near-horizontal bodies of intrusive igneous rocks. Lapoliths form a concave body, phacoliths develop in folded igneous country, and sills form horizontal deposits with thickness determining if they are called sheets (thin) or sills (thick).

Dykes are intrusive structures formed when lava solidifies almost perpendicular to the ground through cracks and fissures in the land. They are commonly found in the western Maharashtra area and are considered feeders for eruptions leading to the development of the Deccan traps.

The core of the earth is made up of very heavy material primarily nickel and iron. It is in a liquid state in the outer core and solid state in the inner core. The core is distinguished from the mantle as the outer core is liquid, while the mantle is mostly solid, extending from Moho's discontinuity to a depth of 2,900 km.