The dark bands represent movement of ice over the ice fall in the summer when more melting occurs, while the light bands represent the movement of ice over the ice fall in the winter.
(The dark bands; represent; movement of ice over the ice fall in the summer) (more melting; occurs; ) (the light bands; represent; the movement of ice over the ice fall in the winter)
The dark bands more melting the light bands
represent occurs represent
movement of ice over the ice fall in the summer
the movement of ice over the ice fall in the winter