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When water collects in the cracks of a rock, it can freeze when temperatures drop. The ice expands and the pressure can split the rock. In cold, mountain regions, one can even hear gunshot-like cracks as rocks are split apart by frost. |
A mechanical process, freeze-thaw weathering causes the joints? (cracks) in rocks to expand, which wedges parts of rocks apart. Because water expands by about 10% when it freezes, this creates outward pressure in rock joints, making the cracks larger.
Joints occur naturally in rocks as a result of their formation. Fractures that are not offset, joints do allow for the entry of water into rocks.
In climates where temperatures dip below freezing in the winter, moisture in the joints of rocks solidifies as ice. Over time, after several cycles of freezing and thawing, joints get large enough that bit of rock start to fall off in smaller pieces. This breakdown of rock happens faster at higher altitudes, where many freeze-thaw cycles can occur during the year.
Credit: Sciencing
Picture Credit : Google
