Question map
Match List-I with List-II and select the correct answer using the code given below the Lists : List-I (Rock Type) A. Sandstone B. Limestone C. Coal D. Shale List-II (Composition) 1. Rock formed from peat or other organic deposits 2. Clay, breaking easily into flat flake plates 3. Calcium carbonate formed by precipitation 4. Cemented sand grains Codes: A B C D
Explanation
Sedimentary rocks are classified based on their composition and mode of formation. Sandstone (A) is a clastic sedimentary rock primarily composed of sand grains, often quartz, that have been cemented together [2]. Limestone (B) is a non-clastic rock composed of calcium carbonate, which can form through the chemical precipitation of minerals or the accumulation of organic remains like shells. Coal (C) is an organic sedimentary rock formed from the compaction and lithification of peat or other accumulated plant matter over millions of years. Shale (D) is a fine-grained clastic rock formed from the compaction of clay and silt, characterized by its ability to break easily into flat, flaky plates [3]. Matching these descriptions leads to the sequence A-4, B-3, C-1, and D-2.
Sources
- [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > Some Examples of Metamorphosis > p. 174
- [3] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 8: Limestone and Chalk Landforms > Limestone and Chalk > p. 76