Groundwater

•! Water that lies beneath the ground surface

•! Fills pore space between grains in sediments or clastic sedimentary rocks

•! Fills cracks and crevices in fractured bedrock

Porosity and Permeability •! Porosity:

–! percentage of rock or sediment that consists of voids or openings

–!Measurement of a rock/sediment s ability to hold water

–!Depends on: •! Original porosity, •! Amount of compaction •! Amount of cementation

Porosity and Permeability •! Permeability:

–!Capacity of a rock or sediment to allow water to pass through them

–!Relates to the degree to which pore spaces are interconnected

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Groundwater residence time

Karst features

stalactites

flowstone

stalagmites

Karst topography

sinkhole

Glaciers and Glaciation

Maximum extent of ice ca. 18 000 years ago

Factors maintaining balance in glacier

Direction of ice flow

Alpine glacier

Continental glacier (ice sheet)

Glacial Erosion

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Up-ice Down-ice

Glacial Erosion

Glacial striae and polish

Chatter marks

Ice flow direction

Glacial Erosion

Direction of ice flow

Glacial Erosional Landscapes

Glacial Erosional Landscapes

During glaciation After glaciation

Glacial Erosional Landscapes

Horn

U-shaped valley

Glacial Deposition

Till

•! Unsorted, unlayered debris carried and deposited by glacier

•! Clay-sized to boulder-sized, mixed together

Glacial Deposition

Erratic: ice-transported boulder that has not been derived from nearby bedrock

Glacial Deposition

time

Moraine: elongate, curved ridge of till

Glacial Deposition

Drumlin: streamlined bodies of till, pointing in the direction of ice flow

Glacial Deposition

Outwash: material deposited by debris-laden glacial meltwater

Well-sorted and layered

Glacial Deposition

Esker: long, sinuous ridge of outwash, formed under or within glacier

Glacial Deposition

Kettle: depressions in outwash left my stranded blocks of ice in front of a receding glacier

Glacial Deposition

Varves: two layers of sediment laid down in a glacial lake that represent the deposition of meltwater sediment in summer (silt) and winter (clay)