Karst Topography and Florida Geology
and Groundwater
Sinkholes: closed depressions caused by dissolution of underlying rock
Sinkholes can form slowly, as rocks dissolve, can also form quickly,
due to collapse of tops of caves.
These collapse sinkholes are often caused by water table drop or loading
on surface.
Signs of sinkhole formation:
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slumping or cracks in structures
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ponding of rainfall
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sediment in nearby well water
Assessing sinkhole danger:
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risk higher where limestone close to surface (< 100 ft)
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look for past sinkholes
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drilling
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ground-penetrating radar, electrical resistivity
Karst topography: shaped by dissolution
Mature karst topography: sinkholes grow together (ex. China) only towers
left behind
Florida Geology
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Piece of Africa left behind when Pangaea broke up
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organism deposit limestone in shallow sea
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covered by clay/sand/silt from Appalachians
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surface covered by sand
Erosion partially removes layers above limestones.Karst topography forms
in “uncovered” limestone.
Floridan Aquifer:
water-table aquifer where limestone is near surface
artesian where covered by thick sediment
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Water comes in at recharge areas and flows toward ocean.
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Water discharges at springs, by upward leakage, and by pumping.
Other important aquifers:
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Sand and Gravel (Panhandle)
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Intermediate (SW Florida)
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Biscayne (S Florida)