EAS201 Lecture Notes - Lecture 6: Spheroidal Weathering, Regolith, Mass Wasting
20 Sep 2016
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Document Summary
Weathering weathering is the mechanical breakdown and chemical alteration of rock and sediment when exposed to air, moisture, and organic matter. Chemical weathering decomposition of rocks and sediments via chemical (and microbial) reactions that (mainly) dissolve minerals. Silicates: regolith and soil carbonates: karst + caves. Begins at joints (fractures without movement = cracks ) formed via cooling, or unloading, or deformation. Basically a fine sand, and there are knobs of granite that have not disintegrated yet. Wedging / exfoliation from unloading + daily heating and cooling. (shingles of the rock basically starting to lift off and then break off) Race tracks / slithering stones happens due to ice that moves the rocks on the playa. Chemical weathering via chemical reactions that dissolve minerals: Bowen"s reaction series: can be viewed as thermodynamic instability of silicate rocks . As you go down, magma gets more viscous. Bowen"s reaction series can be viewed as decreasing thermodynamic stability.
