13 Artesian FormationSloping layer of permeable rock sandwiched between 2 layers of impermeable rockCaprock – impermeable rock layersCan form artesian wellCone of depression:pumping water fromthe well lowers thewater table around it
14 Artesian WellsWell through which water flows freely to the Earth’s surface (in normal wells, it has to be pumped)Artesian formation creates pressure to force water out of the groundIf caprock cracks, can get an artesian spring or well
15 Artesian Well vs. Aquifer In a normal aquifer, rock layersare horizontal and lack a cap.In an artesian formation,the permeable rock layerslopes and is covered by animpermeable layer called caprock.
16 Hot Springs Groundwater passes near magma ands heats up to above 37oC Travertine – mineral deposits from cooled hot springsMud pots - muddy hot springs clayPaint pots – brightly colored clay
22 GeysersHot springs that periodically erupt from surface pools or through small ventsSteam builds up underground and eventually erupts through the vent when the pressure builds upIf there is no steam build up underground, there is no eruption (and therefore, no geyser).
24 Weathering by Groundwater Groundwater passes through soil and other organic minerals and forms carbonic acidGroundwater dissolves and breaks down minerals in the rock
25 Caverns A large cave Stalactites Stalagmite Column Calcite deposited on cave ceilingStalagmiteCalcite deposited on cave floorColumnStalagmite meets stalagtiteHow caverns form: groundwater flows through cracks & carbonic acid dissolves limestone and makes cracks bigger. This eventually makes a cavern.
27 SinkholesCircular depression that forms at the surface when rock dissolves , when sediment is removed, or when caves or mines collapseSubsidence sinkholedepression in groundCollapse sinkholeopen hole in the ground