GEO 120 Lecture Notes - Lecture 17: Clay Minerals, Weathering, Thermal Expansion

• School: URI
• Department: Geosciences
• Course: GEO 120
• Professor: Elizabeth Laliberte

Document Summary

Geo 120 - lecture 17 - weathering - elizabeth laliberte. Changes that occur in rocks and sediments as they come in contact with the atmosphere, hydrosphere, and biosphere. Disintegration of the parent material into smaller and smaller pieces with no change in mineral structure or composition. Thermal expansion - rocks don"t transfer heat > leads to cracks. Deeply buried rocks uncovered by erosion and expand in the vertical direction forming curved sheets. Decomposition of the original parent material forming new minerals and soluble ions. Ions in minerals combine with ions in the atmosphere and hydrosphere. Unaltered minerals from parent rock, ex: quartz. New minerals formed by weathering (feldspar > clay minerals) Frees up elements from rocks which can then be used as nutrients by plants. Factors which affect the rate of weathering are: Smaller the particle size the greater the surface area and hence the more rapid the weathering. Physical removal of material from one place to another.