Comment: 01:55 - 03:00 (01:05)
Source: Annenberg/CPB Resources - Earth Revealed - 15. Weathering and Soils
Keywords: "James Sadd", rock, "sea floor", uplift, orogeny, regression, "environment of formation", "Earth's surface", weathering, polar, tropic, granite, mineral
Our transcription: Most rocks are formed deep beneath the earth's surface or on the ocean floor.
Tectonic activity such as uplift, mountain building or falling sea level, brings these rocks from their environment of formation up to the earth's surface.
There, the rocks are changed into a form that is stable under these new conditions by a process called, "weathering."
Weathering occurs everywhere on earth, be it a cold dry polar region or the hot humid tropics.
This particular outcrop is made of granite.
Now, granite, in its fresh unweathered state is quite hard, because the individual mineral grains are tightly interlocking together.
This granite, however, is heavily weathered.
It's quite soft, crumbles easily because the grains are falling apart, and they're also decomposing chemically.
Weathering occurs in two fundamentally different ways.
The first of these involves the breaking of rock into fragments and individual mineral crystals.
Geology School Keywords