Transcript Karst and Karst Terranes Word is German form of the Yugoslavian term “Kras” means “bare stony ground” Named after investigating a region near.

Karst and Karst Terranes
Word is German form of the Yugoslavian term “Kras”
means “bare stony ground”
Named after investigating a region near the Adriatic Sea in
Yugoslavia
In modern Geomorphology the term refers to any landscape
formed by dissolution of the underlying carbonate bedrock
Characterized by distinctive landforms which don’t typically
occur in any other circumstance
Pseudokarst is the term for karst-like development in noncarbonate lithology that exhibits characteristics similar to
karst landscapes, but which lack dissolution as a primary means
of landscape formation.
Major known Karst regions of the world
Factors affecting Karst
Solubility of Limestone
- percent calcite
Climate
- Temperature and Moisture
Structure of Limestone
- joints, fractures, porosity,
Mineralogy/lithological content
% clastics, % spar vs micrite vs skeletal
Vegetation/Non-carbonate Geology
- acidity (pH) of groundwater
Atmospheric CO2
- affects solubility of Carbonates
Dissolution of Carbonates
CaCO3 dissociates into its constituent ionic components in
water
CaCO3
CaMg(CO3)2
Ca2+ + CO32Ca2+ + Mg2+
(Limestone)
+
2CO32- (Dolomite)
However, dissolution occurs more frequently as a result of a
reaction with carbonic acid formed with carbon dioxide
CaCO3 + H2O + 2CO2
CaMg(CO3)2 + 2H20 + 2CO2
Ca2+ + 2HCO3Ca2+ + Mg2+ + 4HCO3-
Karst Collapse Landforms
Sinkhole - a.k.a. Doline
comes in a variety of shapes
most often funnel shaped
forms as material above a cavity becomes too thin
to support the weight
sometimes filled with colluvium from edges of feature
can form circular lakes
often entrances to caves are found in sinkholes
related to formation of feature
Compound sinks - a.k.a. Uvalas
several sinkholes coalesce to form a larger structure
these may be quite large (a kilometer)
Occasionally, uvalas are floored with alluvium derived
from subterranean streams called a
karst gulf or a polje
A Sinkhole (cockpit) in Central America
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Karst
features
in
Florida
Karst
terrane in
Australia
- a karren plain
with blind valleys
and numerous
sinkholes
A doline (sinkhole)in Winterpark, FL
A 300 ft deep
sinkhole in Guatemala
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“The Blue Hole” is an underwater
sinkhole, 1000 ft across & 400 ft
deep
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Karst Landforms- stream features
chaotic or deranged drainage patterns
few, if any, through flowing streams in karst regions
often exhibit what are called blind valleys
e.g., Lost river, tributaries and other surface
streams in the Mitchell plain
streams disappear into a swallow hole called a ponor, a
swallet, or a sink
-Tolliver Swallow; Stein Swallow
often reappear as a karst spring or a groundwater rise
-Orangeville rise;
-Wesley Chapel Gulf rise
Drainage in a
Karst region in
Europe
-flooded and
backed up into
the overflow
channels
- polje
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A rise of a subterranean stream
Solution pan on a karren in the southwestern USA
Karst landforms- denudation
often large tracts of limestone karst terranes are
devoid of unconsolidated material
these areas are called Karrens
Often karrens have solution enhanced vertical fracture
and joints sets
joints can be filled with debris from dissolution
-known as grikes
or devoid of residuum
-known as kluftkarren or solution grooves
Grikes and/or Kluftkarren - a.k.a.
solution enhanced vertical fractures.
the kluftkarren/grikes divide the
surface into distinct pieces referred
to as Clints
Closeup of a Karren with grikes (note the plants indicating
sediment in the joints
Soils developed in karst terranes
commonly develop a thick red cap called terra
rosa
origins are debated and may be site specific
composed of clay
rich in iron sesquioxide minerals
Commonly thought of as leftovers after intense
leaching of surface rock
May also have contribution by loess and other wind
transported sediments
Less commonly develop another type of soil that is
thin, very permeable and porous called rendzinas
allow extreme infiltration
loamy with pieces of limestone residuum
loess
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terra rosa soil
Karren with
Grikes in Ireland
Grikes or cutters, filled with terra rosa,
shown in cross-section in a roadcut
Karst terranes in high humidity regions
forms a variety of spectacular landforms
Towers, Mounds and Cockpits
-erosional remnants of thick sequences of
limestone that have been greatly degraded
Cockpit karst region in Jamaica
Tower karst
in S.E. China
Tower Karst in S.E. China
Eastern Illinois basin strata and karst development
Mitchell plain
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Mitchell Plain and Chester Escarpment
Sinking stream in karst area of Kentucky
Sinkhole plain in the Kentucky equivalent of the Mitchell Plain