Passage

Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as bitumen, asphalt, and natural gas. Mineral oil originates from the carcasses of tiny animals and plants that lived in the sea. Over millions of years, these dead creatures formed large deposits under the sea-bed; and ocean currents covered them with a blanket of sand and silt. As this material hardened, it became sedimentary rock and effectively shut out the oxygen, preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rock became thicker and heavier. Their pressure produced heat, which transformed the tiny carcasses into crude oil in a process that is still going on today.

QUESTION

CSAT

Easy

Comprehension

Prelims 2013

From the above passage, sedimentary rock leads to the formation of oil deposits because:

Select an option to attempt

Explanation

Statement 1 is incorrect. Saline conditions do not directly relate to the formation of oil. The primary factor in oil formation is the pressure and heat from overlying materials, not the salinity.

Statement 2 is incorrect. The passage clearly mentions that the sedimentary rock "effectively shut out the oxygen" and prevented the complete decomposition of the marine deposits. This lack of oxygen is crucial for oil formation, as it prevents the organic matter from decomposing fully and instead transforms it into oil.

Statement 3 is correct. The passage states that as layers of sedimentary rock became thicker and heavier, their pressure produced heat. This heat, in turn, transformed the tiny carcasses into crude oil. This process is essential for oil formation.

Statement 4 is incorrect. The passage does not mention any specific catalytic substances in sedimentary rock. Instead, it emphasizes the role of pressure and heat generated by the overlying layers.