Answer:
boron and carbon isotope, Phytane, Ice cores, Corals, Lake and ocean sediments etc.
Step-by-step explanation:
- Drillings in ice cores like within ice sheets of Greenlands, Antarctica started in 1956. Collecting core samples of 4 and a half inches and use of molecules of water O 16 and 18 that helps to determine the past atmospheric carbon.
- Corals, skeletal rings have bands of paleo-climatological information and as their body is made of the calcium carbonates these limes creating organisms help to determine the atmospheric concentration of carbon on prehistoric earth.
- The use of oxygen isotope in lakes and oceans has given data related to the content of ocean sediments, and values deposited in clay and sand.
- The use of phytane a diterpenoid alkane that breaks down chlorophyll is used to estimate the ancient Co2 level.