UPSC Prelims 2001 · General Studies
Question 88: Geography
Consider the following statements made about the sedimentary rocks: I. Sedimentary rocks are formed at Earth’s surface by the hydrological system. II. The formation of sedimentary rocks involves the weathering of pre-existing rocks. III. Sedimentary rocks contain fossils. IV. Sedimentary rocks typically occur in layers. Which of these statements are correct?
AnswerThe answer is (d).
All four statements are correct. Sedimentary rocks form at or near the Earth's surface, when weathered fragments of older rocks carried by water, wind or ice settle and harden, or when minerals precipitate. They typically occur in layers (strata) and are the rocks that contain fossils. Remember that sedimentary rocks are layered and fossil-bearing, while igneous and metamorphic rocks seldom hold fossils.
- I. Sedimentary rocks form at the surface through the action of water and other agents.
- II. They form from the weathering of pre-existing rocks.
- III. They contain fossils.
- IV. They typically occur in layers.
Why each option is right or wrong
- (a) III and IV are also correct.
- (b) II and III are also correct.
- (c) I is also correct.
- (d) Right: all four are correct.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2001, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.