At what temperature do rocks generally deform ductilely?

The ductile deformation of rocks occurs at high temperatures, typically at temperatures exceeding about 300 degrees Celsius (or approximately 572 degrees Fahrenheit) within the Earth's crust. At these elevated temperatures, the minerals in the rocks can become more malleable, allowing them to change shape without breaking. This ductility is also influenced by the pressure conditions, as increased pressure can enhance this ability to deform plastically.

In contrast, at very cold temperatures and room temperature, rocks tend to exhibit brittle behavior, breaking or fracturing rather than deforming. Moderate temperatures can lead to some deformation, but it's less pronounced than what occurs at high temperatures. The understanding of how temperature affects rock behavior is crucial in fields such as geology and geophysics, particularly in the study of tectonic movements and metamorphic processes.