Onion skin weathering is caused by when the day is really hot which expands and then in the night is cold which contracts the rock. Overtime the steps are repeated which the rock can’t hold up and the layers of the rock slowly peel it off. This type of weathering is most common where the places like the desert where it’s hot in the daytime and cold in the night. This weathering takes quite a while.
Mechanical
weathering also occurs as the rock heats up and cools down. The changes in
temperature cause the rock to expand and contract. As this happens over and
over again, the rock weakens. Over time, it crumbles.