Karst Processes, Landforms, and Landscapes

Karst Flow Diffuse vs. conduit flow Primary vs. secondary porosity

Karst Materials Carbonate Rocks Limestone Dolomite Other materials Salt Gypsum Ice Permafrost? GEOMORPHLIST Sandstone? Copyright © Carmen Krapf 2002 Cave in sandstone, Namibia

Porosity and Permeability Recrystallization of carbonate Calcite/ aragonite Faulting, jointing Bedding

Carbonate Geochemistry Low-temperature geochemistry Calcite and water; pH ~ 10, ppm Effectively insoluble! Calcite, water, and air CO 2 ; pH ~ 8.4, 50 ppm Very slow – like soil formation Calcite, water, and soil CO 2 ; pH ~ 4-7, <700 ppm H 2 O + CO 2  H 2 CO 3 [carbonic acid] H 2 CO 3  H + + HCO 3 - CaCO 3  Ca ++ + CO 3 -- CO H +  HCO 3 - Now that will eat rock!

Variables Affecting Karst Formation Precipitation Temperature Organic matter Turbulence Copyright © Frank Eckardt 2002

Effects of mixing “Two waters meetin’, limestone is eaten.” Water sources Water table Lakes, etc. Acid sources Cave types Meteoric (CO 2 ) Hydrothermal (H 2 S)

Cavern Formation Where max. solution? Surface Water table Confluence Effects of lithology/ structure

Cave Networks – Wind Cave Note structural control!

Lechuguilla Cave (Carlsbad, NM)

Geochemical transitions Charging w/ soil CO 2 Solution of carbonate Degassing Precipitation of CaCO 3

Speleothems Stalactites Stalagmites Columns Flowstone Cave bacon Cave popcorn Helictites Shields…

Speleothems Copyright © Stephane Veyrat-Charvillon 2002 Copyright © Lynn Fielding 2002

Distribution of Karst Typical of cratons Carbonate + evaporite deposition at high sea-stands

Distribution of Karst Typical of cratons Carbonate + evaporite deposition at high sea-stands Horizontal (diapirs?) Floridan, Interior plateaus, Edwards; Madison

Karst terminology Cvijic (1893) - “krs [karst]” – bleak, waterless Davis, Penck, Bretz Karren, lapies, grike and clint “Sinkholes” Dolines, cenotes, cockpits… Polje, Uvalas Kegelkarst, tower karst Drainage Sinks/springs Valleys – dry, pocket, blind, through Copyright © Jelena Calic-Ljubojevic 2002 Copyright © Andrew Goudie 2002

Karst landscapes

Inputs and outputs

Fundamental Karst Landforms Doline (sinkhole, cenote) Origins Solution Subsidence Collapse

Winter Park sinkhole (1981) 100 m across One day During drought (water table lowering?) On city Web page; now an urban lake.

Cenotes Yucatan, Florida… Developed during glaciations Flooded during interglaciations Explored by diving

Complex Forms Polje (oval); uvala (complex) Copyright © Jelena Calic-Ljubojevic 2002

Karst Landscapes Cockpit karst Tower karst Copyright © Frank Eckardt 2002

What types of karst depression does each of the following lakes occupy? Lake AltamahaTwin LakesCrystal Lake Lake SerenaLake Belle Lake Altamahasolution doline Twin Lakessolution or subsidence uvala Crystal Lakesolution doline Lake Serenasubsidence doline Lake Bellesolution or subsidence uvala

Karst Hydrology Sinks, Swallets, Swallow holes… EX: Map view

Karst Hydrology Sinks, Swallets, Swallow holes, Ponors… EX: Map view Sink Resurgence/spring

Case Study: Mammoth Cave Interior low plateaus Sinkholes and uvala Sinks and springs

Case Study: Mammoth Cave Interior low plateaus Sinkholes and uvala Sinks and springs

Sinkholes, Uvalas, and Caves

Geology Stratigraphy Structure

Block Diagram

Cave Exploration “The Longest Cave” Now over 300 miles of interconnected passages Best explored in drought! Mammoth Cave Flint Cave

Cave Exploration “The Longest Cave” Now over 300 miles of interconnected passages Best explored in drought! Mammoth Cave Flint Cave

Mammoth Cave Evolution Theoretical evolution (undated) Upper = older, lower = younger Incision = interglacial, stability/infilling = glacial TIME