Formation and Characteristics of the Alps

Formation of the Alps

• The Alps, Europe's highest mountain range, formed from the collision of tectonic plates.
• A hundred million years ago, the area was a tropical sea.
• Over millions of years, layers of sedimentary rock accumulated from dead plants and animals.
• Endogenic forces (internal Earth processes) caused tectonic plates to move and collide, forming the mountains.
• About 80 million years ago, the African plate moved north.
• Around 30 million years ago, this plate collided with the Eurasian plate pushing up the mountain ranges.
• The collision caused folding and buckling of sedimentary rock into mountain ranges.
• The process of folding and uplift is like "creasing" the Earth's crust.
• High pressures and temperatures during formation can transform limestone into marble.

Characteristics of Mountain Ranges

• Young mountain ranges (like the Alps) are high, steep, have sharp peaks and deep valleys.
• Older mountain ranges are lower, with gentler slopes and rounder tops.
• This difference is due to exogenic forces (external Earth processes) which erode the mountains over time.

Weathering and Erosion

• Weathering is the breakdown of rock by weather and vegetation.
• Debris from weathering, also known as weathered material, stays where it falls.
• Erosion is the transportation of weathered material by gravity, glaciers, rivers, the sea, and wind.
• Over time, mountains get worn down, and valleys widen.
• Sedimentation is the process where removed material is deposited elsewhere, building up new layers.

Earth's Structure and Processes

• The Earth's crust is a thin layer of solid rock, varying in thickness beneath oceans and continents.
• The Earth's crust is constantly changing due to endo and exogenic forces.
• Endo forces (internal Earth processes) include heat and tectonic plate movement.
• Exo forces (external processes) include weathering and erosion .
• Weathering breaks down rock chemically or mechanically.
• Erosion moves the weathered material.

Relief and Landforms

• Relief refers to the differences in elevation in a landscape.
• Four types of relief include high mountain ranges, low mountain ranges, hills, and lowlands.
• Plains are low-lying areas with little relief.
• Plateaus are high-lying areas with little relief.

Rock Cycle

• The rock cycle describes the continuous transformation of rocks.
• Igneous rock forms from cooled magma or lava.
• Sedimentary rock forms from compressed and cemented weathered material.
• Metamorphic rock forms when existing rock changes due to high temperatures and pressure.

Mechanical and Chemical Weathering

• Mechanical weathering breaks down rock without altering its composition (e.g., frost wedging, thermal expansion).
• Chemical weathering alters the composition of rock by reacting minerals with water or oxygen (e.g., limestone dissolving in acidic water).

Erosion and Deposition

• Erosion is the wearing away of rock by weathered material carried by water, wind, and ice.
• Deposition (or sedimentation) is the process where eroded material is laid down in a new location.