1. Oxidation: This process occurs when iron in rocks reacts with oxygen in the air or water, forming iron oxide (rust). Rust is weaker than the original iron, causing the rock to crumble.
Example: A rusty, crumbling iron fence post.
2. Acid Rain: Rainwater can become acidic due to pollutants in the air like sulfur dioxide and nitrogen oxides. This acidic rain reacts with the minerals in rocks, causing them to dissolve and weaken.
Example: A limestone statue eroded by acid rain, showing distinct pitting and loss of detail.
1. Freeze-Thaw: Water seeps into cracks in rocks. When it freezes, it expands and puts pressure on the rock. Repeated freezing and thawing cycles eventually cause the rock to crack and break apart.
Example: A rock face with jagged, broken edges, indicative of repeated freeze-thaw cycles.
2. Abrasion: Rocks are worn down by the friction of other rocks, sand, or water. This can happen through wind carrying sand particles against rock surfaces, or glaciers dragging rocks and boulders over the land.
Example: A smooth, rounded river stone, polished by the abrasive action of water and sediment.
