Varve

Do you know that when you see the rings in a tree trunk, you can tell how old the tree is? That's because trees grow a new layer every year, and the rings show the different layers.

In the same way, rocks can also show different layers that can tell us about how old they are - this is called varve. Varves are layers of sediment that build up at the bottom of bodies of water, like lakes or rivers. Each year, there may be a new layer of sediment that settles at the bottom, and this forms a new varve.

Varves can be different colors, textures, or thicknesses depending on what was in the sediment that year. For example, if there was a flood, the sediment might have been larger and coarser, creating a thicker layer. If it was a dry year with less sediment, the varve might be thinner.

Scientists can study varves to learn about past climates or environments. By counting the number of varves in a rock, they can find out how many years ago it was formed. They can also analyze the varves to find out what kind of plants or animals lived in the water at that time, and what the weather was like.

So, varves are like layers in a rock that show how old it is, and by studying them, scientists can learn about what the environment was like a long time ago.