Many of the landscapes we witness today have been formed through weathering and erosion processes involving water as a primary element.
Water can find its way into cracks in rocks and freeze to serve as a wedge-splitting wedge to fracture them, while also depositing sediment onto beaches and creating karst topography.
Physical
On Earth, natural forces such as wind, water, and ice are constantly at work eroding away rocks through erosion – this process results in some of the most stunning geological features like mountains and rivers being created as rocks move from their original location and are carried away to other regions by these natural forces.
Wind, water and gravity can move rocks to new locations through mechanical weathering or physical weathering processes. The speed at which these processes operate depends on the type of rock being exposed to these forces – hard granite will weather more slowly than soft limestone for example.
Water is one of the primary agents of mechanical weathering, often eating away at cliff sides to form canyons, freezing into cracks in rock layers and eventually splitting it apart, leading road crews to repair potholes on roadways. Meanwhile, these processes create fascinating geological features such as hoodoos in Bryce Canyon and Goblin Valley.
Chemical
Physical environments contain various forms of weathering. Mechanical weathering is the most prevalent method, caused by daily heating and cooling cycles or by changes in pressure; for instance adding water to cracks in rocks widens them and splits apart the rock surface. Burrowing animals such as rabbits or worms also play an integral part in mechanical weathering by transporting rock fragments closer to the surface for weathering processes.
Chemical weathering can be caused by changes in temperature or by changes to a rock’s composition of minerals. Rainwater contains carbon dioxide dissolved from the air that reacts with rocks to alter their molecular structures; for instance transforming platy silicate minerals (like feldspar) into soft clay minerals.
These minerals eventually break apart into sedimentary rock deposits that are transported by erosion – for example mudslides and waves eroding shorelines – before becoming sedimentary rock itself. Over time these particles may even undergo the process of lithification to become clastic sedimentary rocks.
Biological
Biological weathering refers to the degradation of rocks by plant and animal action or chemical products produced from living things, while mechanical weathering processes often facilitate this process.
Roots from trees and plants grow into cracks or holes in rocks, breaking them apart. Fungi and algae release acids which weaken rock surfaces by dissolving minerals within them. Lichen thalli colonies created from both bacteria and fungi work together in harmony to eject mineral grains from rocks surfaces by alternately wetting and drying.
Animals also contribute to biological weathering by digging and burrowing into rocks; for instance, piddock shells may drill holes into rock surfaces as protection from predators. Agriculture and construction activities, including cultivation and ploughing operations, cause physical and chemical weathering as well as friction caused by foot traffic over time that break down rock surfaces. Erosion plays an essential part in Earth’s ecosystem by shaping mountains and valleys, helping form soil, fighting climate change, capturing carbon emissions, healing environments damaged by human activities, supporting forests growth – all while shaping mountains and valleys, shaping mountains and valleys while creating soil, combatting climate change by capture carbon emissions as well as supporting forests growth.
Environmental
Geologists use the terms weathering, erosion and deposition to refer to processes by which rocks and minerals change shape and are transported across Earth’s surface. Weathering includes breaking apart rocks on Earth’s surface while erosion moves these materials around. Finally, deposition deposits any eroded material.
Water is the principal agent of erosion. Rainwater entering cracks in rocks and then freezing can act like an erosional wedge to break apart rocks; when this ice melts away it also contributes to further erosion.
Different rocks erode at different rates depending on their hardness and duration of exposure; those more vulnerable to weathering and erosion tend to wear away faster than harder, less vulnerable rocks.
Rock types vary in texture and composition, which results in distinctive geological features. For instance, the Grand Canyon was formed over millions of years by river flow while Utah’s Bryce and Goblin Valley National Parks’ Hoodoo formations are the product of wind erosion.