How can varves be used to construct a timeline of environmental changes?
A
Varves record annual freezes and thaws and contain bubbles of air that can tell us about how the atmosphere changed.B
Varves contain radioactive isotopes that decay at a steady rate and can be used to determine the relative ages of sediment layers.C
Varves record seasonal deposition of sediments in glaciers and lakes and contain pollen that tells us about past environments.D
Varves can be correlated between distant locations to provide a continuous record of climate change throughout Earth's history.