Earth Sciences 1022A/B Lecture 5: Lecture 5 - Weathering

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1022A/B
• Professor: Stephen R Hicock

Document Summary

Mechanical weathering y breaking up rock into smaller pieces, providing more surfaces for chemical. Lecture 5 notes weathering attack y mechanisms: y physical weathering: frost wedging. water freezes in rock fractures and expands 9%, prying rock apart. occurs in high altitude, low temperature areas. broken off material called a talus slope: unloading. pressure release ock surface expands after stuff on top is removed, slabs break off: biologic activity. plant roots grow in rock fractures and pry the fractures open. also known as root wedging y chemical weathering: dissolution/dissolve. co2 dissolves in water to make weak carbonic acid that dissolves rock minerals. will eventually dissolve almost anything: oxidation, hydrolysis. dark silicates react with oxygen y rusting. orthoclase in granite changes to clay by exchanging large k+ ions for tiny h+ y especially potassium feldspar. Involves water = hydro y rates of weathering: rock characteristics.