1. Plate Tectonics:
* The Earth's crust is divided into large, moving plates called tectonic plates.
* Convergent boundaries are where two plates collide. There are three types:
* Continental-Continental Collision: Two continental plates collide, causing intense compression and uplifting, forming mountain ranges like the Himalayas.
* Oceanic-Continental Collision: An oceanic plate subducts (dives) under a continental plate, leading to volcanic activity and mountain formation along the continental edge, like the Andes Mountains.
* Oceanic-Oceanic Collision: Two oceanic plates collide, causing one to subduct under the other, leading to the formation of volcanic island arcs, like the Mariana Islands.
2. Folding and Faulting:
* Folding: The immense pressure from the colliding plates forces the layers of rock to bend and fold into wave-like structures. These folds can be gentle or sharp, depending on the intensity of the pressure.
* Faulting: When the pressure becomes too great, the rocks can break and fracture, creating faults. These faults can be vertical (like the San Andreas Fault) or horizontal, and can cause the land on either side to shift up, down, or sideways.
3. Uplift and Erosion:
* Uplift: The combined forces of folding and faulting push the layers of rock upward, creating mountains.
* Erosion: Once the mountains are formed, weathering and erosion by wind, water, and ice carve and shape their features, further altering the landscape.
In summary:
Orogeny is a long and ongoing process driven by plate tectonics. It involves immense pressure, bending, fracturing, and uplift, ultimately leading to the formation of mountain ranges. The landscape of mountains is constantly evolving due to the ongoing forces of uplift and erosion.
