* Thermal Expansion and Contraction: Rocks expand when heated and contract when cooled. These changes in volume put stress on the rock's structure. When temperatures drop, the contraction can cause the rock to become more brittle and prone to fracturing.

* Water in Rocks: Rocks often contain water in their pores and cracks. As temperatures decrease, this water can freeze and expand, putting pressure on the rock. This can lead to the rock becoming more brittle and prone to cracking.

* Change in Mineral Behavior: Some minerals in rocks behave differently at lower temperatures. For example, certain clays can become more brittle at lower temperatures.

* Impact on Chemical Reactions: Lower temperatures slow down chemical reactions within rocks. These reactions can help maintain the rock's integrity, so a decrease in temperature can weaken the rock structure.

Examples of Lower Temperatures Affecting Rocks:

* Frost Wedging: Water freezing in cracks of rocks expands and can cause the rock to break apart.

* Glacial Erosion: The extreme cold of glaciers causes rocks to become more brittle and easier to break, contributing to the erosive power of glaciers.

Overall, lower temperatures make rocks more susceptible to breaking and fracturing due to increased brittleness.