ERSC 1F90 Lecture Notes - Lecture 10: Hardpan, Water Cycle, Paleosol
9 Apr 2015
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Document Summary
Weathering and soils: the link between hard rocks and sediments. Internal processes: earth"s surface gradually elevate (plate tectonics, mountain building, volcanics etc. ) Weathering is the first step in the development of sedimentary rocks. Talus (weathered debris) builds at the base of cliffs/mountains (force of gravity/mass wasting) Weathering refers to breaking (physical) things into smaller pieces and corrode (chemical) Mechanical weathering: breaking rocks into smaller pieces by physical forces doesn"t change chemical composition of rocks: increases surface area, exposing more surfaces to chemical weathering, weathering transforms solid rock into sedimentary particles (clasts) or dissolved ion. Clasts range in size from coarse (gravel) to fine (mud). Sheeting: large masses of igneous rocks exposed by erosion and concentric slabs begin to loosen. Exfoliation domes: created when slabs separate and spall off. **pluton: small granitic body that doesn"t meet the surface. Water goes between cracks, freezes and expands and breaks the rock. Creates talus slopes (piles of broken rocks)
