Which one of the following is NOT a palaeoclimatic geological indicator?

Palaeoclimatic indicators (proxies) are categorized into specific groups based on their nature and origin. The standard classification is as follows:

• Geological Indicators: These include lacustrine deposits (lake sediments), evaporite deposits (minerals left after evaporation), glacial deposits, and aeolian (wind-blown) deposits.
• Cryogenic Indicators: These refer specifically to ice sheets and ice cores. While they provide geological-scale history, they are categorized as cryogenic because they originate from the cryosphere.
• Biological Indicators: These include tree rings, pollen, and fossils.

Since ice sheets and ice cores are classified as cryogenic indicators, they are the correct answer for the indicator that is NOT considered geological in this framework. Sedimentary deposits is a general term for the rocks/layers that form the geological record, thus making it part of the geological category.