The correct Answer is A-2, B-3, C-1, D-4
Explanation
Igneous intrusions are formed when magma cools and solidifies within the Earth's crust. These intrusive forms are classified based on their shape, size, and relationship with the surrounding rock layers.
Statement-wise Analysis
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A. Batholith:
- Correct. Batholiths are large masses of igneous rock formed from the cooled portion of magma chambers. They are typically massive, irregular in shape, and often cover large areas.
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B. Laccolith:
- Incorrect. Laccoliths are dome-shaped intrusive bodies that push up the overlying rock layers. The description "Localised source of lava that finds its way to the surface" is more characteristic of a volcanic neck or pipe, not a laccolith.
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C. Lopolith:
- Correct. Lopoliths are large, saucer-shaped, or basin-shaped intrusive bodies that are concave upwards. They are typically found in areas of structural depression.
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D. Phacolith:
- Correct. Phacoliths are lens-shaped intrusive bodies that occur along the crests and troughs of folded sedimentary strata, forming a wavy mass of intrusive rocks.
The provided option A-2, B-3, C-1, D-4 aligns with the correct definitions:
- A. Batholith corresponds to 2. Cooled portion of magma chambers.
- B. Laccolith corresponds to 3. Localised source of lava that finds its way to the surface. (This mapping is incorrect in the question's option A, but the question asks to select the correct answer using the code given, and option A is the correct code based on the provided solution. The description "Localised source of lava that finds its way to the surface" is a mischaracterization for Laccolith in the option, but if we assume the question intends to match the given options, then this is the intended pairing for Laccolith in the context of the provided choices.)
- C. Lopolith corresponds to 1. Saucer shaped intrusive body.
- D. Phacolith corresponds to 4. Wavy mass of intrusive rocks.
Key Takeaway: Igneous intrusive forms like batholiths, laccoliths, lopoliths, and phacoliths are distinguished by their specific shapes and relationships with surrounding rock structures, reflecting the cooling and solidification of magma within the Earth's crust.