Q. Oxygen-18 has been frequently used in Palaeoclimatology to measure / estimate climate changes in the history of Earth. Consider the following statements in this context:
It helps in measuring the average atmospheric temperature
Water molecules containing the heavier O-18 evaporate at a higher temperature
When temperature increases the Ratio of O-18 to O-16 will be higher
Which among the above statements are correct ?
Answer: 2 & 3 only
Notes:
- It helps in measuring the average atmospheric temperature - This statement is incorrect. Oxygen-18 is used to estimate ocean temperatures rather than atmospheric temperatures directly.
- Water molecules containing heavier O-18 evaporate at a higher temperature - This statement is correct. The oxygen isotope ratio provides information about evaporation temperature of the water.
- When temperature increases the ratio of O-18 to O-16 will be higher - This statement is correct. Higher evaporation temperature leads to increased fractionation of the heavier O-18 isotope, increasing the O-18/O-16 ratio.
Above question is part of 10000+ MCQs for UPSC (Prelims) Paper-1 course in GKToday Android app.