302-Lecture 4

General Outline

Weathering Processes and Landforms

I. Definitions: weathering and regolith

II. Products of weathering

A. clastics (boulders, cobbles, gravel, sand, silt, clay minerals)

B. clastic sedimentary rocks

C. soil materials

III. Physical (mechanical) weathering

A. frost wedging

B. crystal growth (ice, salts) and granular disintegration

C. thermal expansion

D. fluid transport: abrasion and crushing

E. action of plants and animals

F. exfoliation from pressure unloading (large-scale)

IV. Chemical weathering: most rock forming minerals at earth’s surface are unstable

A. Bowen reaction and Goldrich weathering series

B. Mineral abundance and susceptibility

C. Common chemical reactions: hydrolysis, oxidation, carbonation

D. Spheroid weathering

E. Climate controls and spatial patterns of weathering

V. Chemical weathering of carbonate rocks (limestone and dolostone); Karst topography

A. Chemical reactions, solubility

B. Phreatic theory of cave formation

C. Characteristics of karst terrain

D. Tower karst and phytokarst

E. Caprocks and hardpans