Frost wedging is a type of mechanical weathering caused by frost and ice. Water expands when it freezes, and repeated cycles of freezing and thawing slowly weaken the structural integrity of porous and cracked rocks. Over time, frost wedging enlarges tiny cracks into huge fissures. The fissures eventually split the rock completely.Know More
Frost wedging is a slow, cyclical process. During the day, liquid water warmed by the sun trickles into microscopic pores, cracks and spaces in rock. When the sun sets and the temperature drops, the water freezes and expands by 9 percent, exerting pressure on the surrounding rock. When the sun rises again, the frost melts and the water flows deeper into the expanded crack, where it freezes after sunset.
The most obvious evidence of frost wedging is the flat, plate-like surface created when the expanded rock joints finally split. Huge rock formations shaped by glaciers often display such sharp, flat faces. Frost wedging occurs only in climates that are cool to cold throughout the year. Canada, Scandinavia, northern Russia and Antarctica are particularly prone to this kind of weathering.
All types of weathering take place over time. However, biological factors that weaken rock serve as catalysts, decreasing the amount of time necessary for drastic change to happen. For example, moss and lichen weaken and destabilize small cracks in the rocks where they grow, making the material more vulnerable to the effects of expanding frost.Learn more about Erosion & Weathering
Lateral erosion is one of the three different ways that rivers and streams erode their banks and beds. As the term implies, lateral erosion is the erosion that occurs on the sides, or floodplains, of a river or stream, and it is also referred to as bank erosion. The other two forms of erosion are headward erosion and downcutting erosion.Full Answer >
Erosion is a process that causes the soil surface to wear out; geological erosion is caused naturally by water, wind or gravity, and accelerated erosion is caused by human use of land. Geologists estimate that 70 percent of soil erosion is caused by human activities like excessive construction, agriculture, surface mining and forestry.Full Answer >
A sinkhole is the result of the surface layer of the ground collapsing, causing a depression to form beneath. Sinkholes can range in size from tiny to massive, anywhere between only a few feet in diameter to miles across. Sinkholes are found all over the earth, and while some take years to develop, others form rapidly.Full Answer >
The three main types of wind erosion are suspension, saltation and creep. Suspension is the blowing of tiny particles into the air where they may be carried for long distances, saltation is the repeated lifting and dropping of slightly larger particles, and creep is the movement of particles too large to lift along the ground. All types only occur with relatively dry, loose soils that wind can break apart.Full Answer >