Following are the intrusive landforms of volcanic activity and their characteristic features:

I. Batholiths: Huge mass of igneous rocks, usually granite at the deeper layers of the crust.

II. Phacoliths: Large igneous mounds with a dome-shaped upper surface.

III. Dykes Wall-like structures developed by solidifying almost perpendicular to the ground.
IV. Sills: The near horizontal bodies of intrusive igneous rocks.

Which of the above are correctly matched?

Key Points

• Batholiths: These are massive formations of igneous rock, typically granite, found deep within the Earth's crust. They form the core of many mountain ranges.
• Dykes: Dykes are vertical or steeply inclined sheets of rock that have intruded into a crack in pre-existing rocks. They solidify perpendicular to the ground and often cut across the surrounding rock layers.
• Sills: Sills are horizontal or near-horizontal bodies of intrusive igneous rock that have intruded between older layers of rock. They are parallel to the bedding planes of the surrounding sedimentary rocks.
• Phacoliths: The term Phacoliths is incorrectly described in the options. They are actually lens-shaped masses of intrusive igneous rock that occupy folds in the surrounding strata, often found in anticlines or synclines.

Additional Information

• Intrusive Landforms:
  • Batholiths: These are large masses of intrusive igneous rock that have solidified deep within the Earth's crust. They often form the cores of mountains and can cover areas of hundreds of square kilometers.
  • Dykes: Dykes are formed when magma intrudes into a crack then solidifies as a sheet-like body that cuts across pre-existing rock layers. They are typically vertical or steeply inclined.
  • Sills: Sills are formed when magma intrudes between the layers of sedimentary rock, solidifying into a horizontal or gently inclined body. Unlike dykes, sills are parallel to the bedding planes of the surrounding rock.
  • Phacoliths: These are lens-shaped masses of igneous rock that are often found in the folds of mountain ranges. They are typically associated with anticlines and synclines in folded sedimentary rock layers.