Folded Mountains
Picture a thick piece of cloth spread on a table. Now, push both ends of the cloth towards the center. What happens? It crumples into folds, creating ridges and valleys.
This is exactly what happens when two massive tectonic plates—the gigantic puzzle pieces of Earth’s crust—collide under immense pressure. The rocks between them do not have enough space to escape, so they bend and fold, rising into enormous mountain ranges.
This process is known as orogeny, and the mountains formed through this are called Folded Mountains. These mountains are the highest and most extensive on Earth and are found in all the continents.
So, Folded mountains are formed due to folding of crustal rocks by compressive forces generated by Endogenetic forces coming from within the earth.
Now, if you open a world map, you’ll notice a pattern: folded mountains are generally found along the margins of continents, mostly in a north-south or east-west direction. This is no coincidence; it’s a direct result of plate tectonics.
Some famous examples include:
- Himalayas (Asia)
- Alps (Europe)
- Rockies (North America)
- Andes (South America)
- Appalachians (North America)
- Urals (Europe-Asia border)
- Aravallis (India)
- Atlas Mountains (Africa)
Each of these mountain ranges is a testament to millions of years of struggle and transformation, sculpted by Earth’s internal forces.
Old vs. New: The Age of Folded Mountains
Mountains, like humans, have different stages of life. Some are young, energetic, and still growing, while others are old, worn down, and eroded.
1. Old Folded Mountains (Relict Mountains)
These mountains originated before the Tertiary Period (more than 66 million years ago) and have been heavily eroded over time. What were once towering peaks have now become rolling hills and low ridges.
- Examples: Aravallis (India), Appalachians (USA), Urals (Russia)
- Think of these mountains like wise elders, who have seen millions of years of Earth’s history.
2. New Folded Mountains
These mountains are younger and were formed during the Tertiary Period (less than 66 million years ago). They are tall, rugged, and still growing as the tectonic forces continue to push them upward.
- Examples: Himalayas, Alps, Andes, Rockies
- These are the youthful mountains, full of energy, still rising, and still experiencing earthquakes due to ongoing plate movements.
The Himalayas, for example, are still growing by about 5 mm every year as the Indian Plate continues to push against the Eurasian Plate.
Key Characteristics of Folded Mountains
1️⃣ Youngest and Most Dynamic
- Folded mountains are among the newest landforms on Earth’s surface.
- They are still rising due to continuous tectonic activity.
2️⃣ Formed from Oceanic Sediments
- Millions of years ago, these mountains were part of ancient ocean basins!
- As plates moved, the sediments deposited in oceanic trenches got compressed and solidified into rock layers, which later folded into mountains.
3️⃣ Long but Narrow
- Folded mountains are long chains stretching across continents.
- Their length is far greater than their width—think of them like a tightly packed accordion.
4️⃣ Arc-Shaped Structure
- Many folded mountains curve into an arc due to the way plates collide.
- One side is concave (inward-sloping), and the other is convex (outward-sloping)—like a massive geological bow.
5️⃣ Found Along Continental Margins
- Most of them face the ocean, as tectonic plates often meet near continental edges.
- The Rockies and Andes, for example, run along the western edges of North and South America, respectively.
- These mountains are often part of a larger system called Cordilleras (a Spanish term meaning “chain of mountains”).
