weathering - Sedimentary rocks are the product of the...

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Sedimentary rocks are the product of the creation, transport, deposition, and diagenesis of detritus and solutes derived from pre-existing rocks.
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Sedimentary rocks are the product of the creation , transport, deposition, and diagenesis of detritus and solutes derived from pre-existing rocks.
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Weathering Physical and chemical weathering break down pre- existing rocks into smaller components (gravel, sand, clay, solutes) that can then be transported, deposited, and lithified to create sedimentary rocks. physical weathering : disaggregation of rocks and minerals by mechanical processes chemical weathering : decomposition and disaggregation of rocks and minerals as a result of chemical reactions. Weathering is an essential component of the rock cycle and other important biogeochemical cycles.
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Weathering Weathering Physical weathering volume changes freeze-thaw insolation mineral reactions unloading biologic activity Chemical weathering dissolution hydration/dehydration hydrolysis redox
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Volume Changes: Freeze-Thaw The freezing of water yields a 9-10% volume increase, imparting significant stresses onto solid materials that confine liquid water. Repeated freezing and thawing physically disaggregate parent rocks in the middle latitudes. The most favorable conditions occur in fractured, porous source rocks.
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Volume Changes: Freeze-Thaw
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Volume Changes: Insolation Thermal expansion of parent rocks Thermal expansion of parent rocks generate important generate important stresses that can that can fracture and disaggregate them. fracture and disaggregate them. differential expansion & contraction
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Volume Changes: Mineral Reactions Certain minerals undergo chemical transformations at Earth’s surface P-T and chemical conditions (these are also forms of chemical weathering). anhydrite + water = gypsum smectite + water = fat smectite When confined by fractures and in pore spaces, these minerals can contribute to the physical disaggregation of source rocks.
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Current Action Wind and water currents impart stresses onto source rocks. These stresses (σ = F/A = m*a/A) are locally
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This note was uploaded on 06/03/2011 for the course GEOL 201 taught by Professor Baruah during the Fall '10 term at South Carolina.

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weathering - Sedimentary rocks are the product of the...

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