Varves Flashcards
1
Q
What are varves made of?
A
The coarses, lighter-coloured layer is the spring and summer deposition when meltwater is at its peak and the meltwater streams are carrying maximum load.
The thinner, darker-coloured and finer silt settles during autumn and through the winter as stream discharge decreases and the very fine sediment in the lake settles to the bottom.
2
Q
Why are varves useful?
A
They are a good indicator of the age of lake sediments and of past climates as the thickness of each varve indicates warmer and colder periods.
3
Q
What is a varve?
A
Lakes on the fringe of the ice are filled with deposits that show a distinct layering.
A layer of silt lying on top of a layer of sand represents 1 year’s deposition in the lake and is known as a varve.
