Question map
Consider the following statements : 1. Coal is a sedimentary rock. 2. Basalt is an igneous rock. Which of the statements given above is/are correct?
Explanation
Statement 1 is correct as coal is classified as an organically formed sedimentary rock. It originates from the accumulation of vegetative matter in swamps and forests, which is subsequently compressed by the pressure of overlying sediments into carbon-rich masses like peat, lignite, and coal [c3, c5, t5]. Statement 2 is also correct; basalt is a primary igneous rock. Specifically, it is an extrusive or volcanic igneous rock formed when molten lava reaches the Earth's surface and cools rapidly, resulting in a fine-grained texture [c4, t1, t3]. Basalt is characteristically dense, dark, and rich in iron and magnesium [t1, t4]. Since both statements accurately describe the classification of coal and basalt respectively, the correct option is 3.
Sources
- [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.2. Sedimentary Rocks or Detrital Rocks > p. 171
- [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > SEDIMENTARY ROCKS > p. 19
- [3] https://www.eia.gov/energyexplained/coal/
- [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.1. Igneous Rocks or Primary rocks > p. 169
- [5] https://geology.utah.gov/map-pub/survey-notes/glad-you-asked/igneous-sedimentary-metamorphic-rocks/
- [6] https://dep.nj.gov/wp-content/uploads/njgws/enviroed/classroom-materials/lessons-by-grade/rocks_sedimentsnewjersey-1.pdf