Lesson 2: Uplift and Weathering

Key Idea

Uplift acts as the bridge between the deep Earth and the atmosphere. Rocks formed deep underground exist in a high-pressure, high-temperature environment where they are stable.

However, when vertical plate motion forces these rocks to the surface, they enter a hostile new environment. Suddenly exposed to air, water, and fluctuating temperatures, the rock is no longer stable. This drastic change in environment—caused by uplift—is the trigger that allows transformation to begin.

Key Idea

Mountain ranges illustrate a battle between two energy sources. Earth's internal energy drives the plates that push mountains upward. Simultaneously, solar energy drives the wind and rain that tear mountains down.

This interaction defines the cycle of erosion. As fast as internal energy builds a peak through uplift, solar-powered weathering attacks it, breaking the solid rock into loose sediment. The mountain is built by the Earth, but it is destroyed by the Sun.