Correct Option
The correct option is A-3, B-2, C-4, D-1
Explanation
Rocks are classified into three major groups based on their mode of formation: Igneous (formed from cooling magma/lava), Sedimentary (formed from accumulation of fragments), and Metamorphic (formed from alteration under heat and pressure). Igneous rocks are further divided into intrusive (plutonic) and extrusive (volcanic) based on where the cooling occurs.
Detailed Analysis
- A. Basalt (Matches 3 - Extrusive Igneous): Basalt is a fine-grained igneous rock formed from the rapid cooling of lava exposed at or very near the surface of the Earth. Since it solidifies on the surface, it is classified as Extrusive Igneous rock.
- B. Granite (Matches 2 - Intrusive Igneous): Granite is a coarse-grained igneous rock formed from the slow cooling of magma deep beneath the Earth's crust. Because it solidifies inside the crust, it is classified as Intrusive Igneous (or Plutonic) rock.
- C. Sandstone (Matches 4 - Sedimentary): Sandstone is formed by the accumulation and lithification (cementing) of sand grains (mineral particles or rock fragments). It is a classic example of a Sedimentary rock, specifically mechanically formed.
- D. Marble (Matches 1 - Metamorphic): Marble is formed when limestone is subjected to intense heat and pressure, causing recrystallization. This process changes the original rock into a Metamorphic rock.
Conclusion:
- A matches 3
- B matches 2
- C matches 4
- D matches 1
Key Takeaway: The primary distinction in igneous rocks lies in the cooling location: Intrusive rocks (e.g., Granite) cool slowly beneath the surface resulting in large crystals, while Extrusive rocks (e.g., Basalt) cool rapidly on the surface resulting in fine crystals.