Earth Sciences 4462A/B Lecture Notes - Lecture 2: Overbank, Point Bar, Silt
16 Oct 2015
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Document Summary
Glacial stratigraphy, genesis, and facies analysis are useful for nding sources of placer ores and industrial minerals such as aggregate, clay and silica sand. Aggregate - sand and gravel used for construction (worth > billion/year) Mixed with cement to make concrete used in buildings and bridges. Mixed with bitumen to make asphalt used in roads and parking lots; trench llings to lay pipes and cables; or foundry sand, lter media, and foundation pads. Ideal aggregate is well graded clean sandy gravel that will bond well with cement to provide a strong structural material and reduce the amount of cement needed. Sources need to be located close to construction sites because because of transport costs; urban development on aggregate reserves can cause political problems later on. Stone types in aggregate affect its quality; depositional, transport history important. Glacial washout usually best source of aggregate with its consistent grain size, sorting, thickness, and extent.
