This page provides a brief outline of, lists the main points of, gives links to figures for, and lists the assigned reading for a lecture in Dr. Bruce Railsback's GEOL 1121 class at the University of Georgia. This page is not intended as a set of lecture notes, and it cannot subsititute for a set of lecture notes. Familiarity with this page alone will not assure satisfactory grades on exams in the course.

Lecture 21 (Monday, March 11, 2002): Chemical Weathering

Brief outline of this lecture:
Chemical weathering
Reactions in chemical weathering
Products of chemical weathering
Differences in chemical weathering with climate
     

Main points of this lecture:
Chemical weathering produces new minerals and dissolved ions.
Production of CO2 in soils is critical to chemical weathering.
Different elements tend to go to those two groups.
Availability of water influences how thoroughly elements are removed by solutions.
Most weathering of silicates produces dissolved bicarbonate (HCO3-.

Figures used in this lecture:
Chemical Weathering - a coffee-maker model
A convenient abridged periodic table
Chemical Weathering - An introduction and two kinds of reactions
Oxidation on the Periodic Table
Images of pyrite and iron oxides - an example of oxidation
Plants, CO2, and carbonic acid
Chemical Weathering - Hydrolysis of Silicates
Chemical Weathering - Hydrolysis of Silicates in different climates
Chemical Weathering - the coffee-maker model in different climates
Chemical weathering on the Periodic Table
Formation of Caliche
Susceptibilty of silicate minerals to chemical weathering
Results of chemical weathering

Reading assignment: pp. 251-253.


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Railsback's main 1121 web page
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UGA Geology Department web page