GEOL105 Lecture Notes - Lecture 8: Soil Liquefaction, Soil Retrogression And Degradation, Sinkhole

• School: University of Delaware
• Department: Geology
• Course: GEOL105
• Professor: Kohut Edward

Document Summary

Although soil may be eroded and transported elsewhere, all layers initially form together in place. Becomes hazard when rate of erosion exceeds rate of formation a- topsoil. Loss of farm topsoil a growing problem worldwide. Soil erosion can be greatly accelerated by: drought - floods, deforestation - poor farming practices, overgrazing. Some soils contain the clay smectite: expands when wet, shrink when dry. Causes building challenges and damage where it is present. May be caused by: groundwater removal, oil and gas removal, mining, natural compaction of sediments. May cause areas to be more prone to ooding. Usually in carbonate rocks ( made of mineral calcite ) Usually triggered by natural processes but may be aggregated by: excess groundwater withdrawal, added weight of construction. Co2 in atmosphere forms carbonic acid in rain and snow. Carbonic acid dissolves carbonate rocks (limestones and marble) Sinkholes often triggered by groundwater and/or adding weight.