Karst Landforms
Lapies & Pavements · Swallow Holes, Sinkholes, Dolines, Uvalas & Poljes · Caves & Tunnels · Speleothems (28 Micro-Realms)
Surface Solution Depressions & Subterranean Dripstone Architecture (NCERT Chapter 7)
Karst topography is uniquely characterized by the absence of surface drainage and the dominance of underground conduits. On the surface, chemical solution carves jagged Lapies (which smooth into Limestone Pavements) and a coalescing hierarchy of closed depressions: Swallow Holes $\to$ Solution & Collapse Sinkholes (Dolines) $\to$ Valley Sinks (Uvalas) $\to$ Poljes. Underground, bedding-plane dissolution excavates Caves and Tunnels adorned by depositional calcite Stalactites, Stalagmites, and Pillars.
I. Erosional Surface Landforms: Lapies, Pavements, Sinkholes & Uvalas (NCERT)
Lapies (Karren)
- Irregular maze of pits, trenches & ridges
- Most of the limestone is eaten away
- Differential solution along parallel joints
Limestone Pavements
- Lapies fields eventually turn into
- Smooth Limestone Pavements (NCERT)
- Flat blocks (Clints) & joint clefts (Grikes)
Swallow Holes (NCERT)
- Small to medium sized round to
- Sub-rounded shallow depressions
- Form on surface of limestones by solution
Solution Sinkholes
- Circular at top & funnel-shaped towards bottom
- Depth from <0.5 m to 30+ m (avg 3–9 m)
- More common than collapse sinks (NCERT)!
Collapse Sinks (Dolines)
- Bottom of sinkhole forms roof of underground void
- Roof collapses leaving steep chasm
- Termed as Dolines (NCERT exact term)
Valley Sinks (Uvalas)
- Adjacent sinkholes & dolines join together
- By slumping of materials or roof collapse
- Long, narrow to wide trenches = Uvalas
Poljes (Structural Basins)
- Largest closed karst depression (km-scale)
- Steep faulted walls + flat alluvial floor
- Blanketed by fertile red Terra Rossa clay
II. Vanishing Valleys, Caves, Tunnels & Natural Bridges (NCERT Core)
Sinking Creeks & Ponors
- Surface streams disappear underground
- Through swallow holes & sinkholes (Ponors)
- Re-emerge km away as karst springs
Blind & Dry Valleys
- Blind Valley: Ends abruptly at a cliff swallow hole
- Dry Valley: Former valley left waterless
- After stream diverted underground
Caves vs. Karst Tunnels
- Cave:Normally has an opening at one end
- Caves with openings at BOTH ends
- Are called Tunnels (NCERT High-Yield)!
Phreatic vs. Vadose Caves
- Phreatic tube: Circular pressure conduit
- Vadose canyon: Downcut slot trench
- Combined = Classic Keyhole cross-section
Karst Window (Fenster)
- Section of cavern roof collapses
- Exposes subterranean river to daylight
- Flows back into dark tunnel downstream
Karst Natural Bridges
- Most of a cave tunnel roof collapses
- Single uncollapsed rock arch remains
- Spans across the valley as Natural Bridge
Vauclusian Resurgences
- Underground river hits impermeable shale
- Emerges at surface as high-discharge spring
- Verinag, Kokernag & Achabal (Kashmir)
III. Depositional Landforms: Stalactites, Stalagmites & Pillars (NCERT Core)
Dripstone Genesis
- Water carrying $\text{Ca(HCO}_3)_2$ enters cave air
- Evaporates or loses dissolved $\text{CO}_2$
- Deposits calcite right on ceiling or floor
1. Stalactites (Roof Icicles)
- Hang as icicles of different diameters
- Broad at their bases & taper towards
- Free ends hanging from cave roof (NCERT)
Soda-Straw Stalactites
- Initial embryonic stage of stalactite
- Hollow thin-walled calcite ring tube
- Water flows down central canal
2. Stalagmites (Floor Mounds)
- Rise up from the floor of the caves
- Formed by water dripping from surface
- Or through pipe of stalactite above (NCERT)
Stalagmite Shapes (NCERT)
- May take the shape of a:
- 1) Column, 2) Disc, with either a
- Smooth rounded bulge or miniature crater
3. Pillars & Columns
- Stalactite & stalagmite eventually fuse
- Form complete roof-to-floor Pillars
- And Columns of different diameters (NCERT)
Helictites, Curtains & Tufa
- Helictite: Gravity-defying twisted twigs
- Drapery/Curtain: Thin wavy wall sheet
- Travertine & Tufa: Surface spring terraces
IV. Residual Tower Karst, Paleoclimate Archives & Indian Gallery
Residual Hums & Pepinos
- Senile stage of karst erosion cycle
- Isolated haystack limestone hills (Hums)
- Equivalent to Monadnocks on a Peneplain
Cockpit / Cone Karst
- Star-shaped solution depressions (Cockpits)
- Surrounded by hemispherical limestone cones
- Jamaica Cockpit Country & Bohol Chocolate Hills
Tower Karst (Mogotes)
- Vertical-walled 100–300 m limestone towers
- Rising above flat alluvial plain or sea
- Guilin (China), Viñales (Cuba) & Ha Long Bay
Pinnacle Stone Forests
- Razor-sharp giant mega-lapies needles
- 20–50 m tall vertical limestone blades
- Shilin (Yunnan) & Tsingy (Madagascar)
Mawmluh Cave GSSP
- Stalagmite $\delta^{18}\text{O}$ rings record monsoon droughts
- Mawmluh Cave (Meghalaya) chosen by IUGS
- Global boundary for Meghalayan Age!
Indian Karst Landforms
- Meghalaya: Krem Liat Prah, Krem Puri, Mawsmai
- Andhra: Borra (Ananthagiri) & Belum Caves
- Chhattisgarh: Kutumsar; Andaman: Baratang
Erosional vs. Depositional
POOLS · SINKS · CAVES
STALACTITE · PILLAR
- Erosional: Pools, Sinkholes, Lapies, Pavements, Caves
- Depositional: Stalactites, Stalagmites, Pillars
- Completes Groundwater & Karst (NCERT Ch 7)
Core Distinctions
• Erosional Landforms: Pools, Swallow Holes, Sinkholes (Solution & Collapse/Dolines), Valley Sinks (Uvalas), Lapies, Limestone Pavements, Caves, and Tunnels.
• Depositional Landforms: Stalactites, Stalagmites, and Pillars (Columns).
• A Cave normally has an opening at one end, whereas caves with openings at both ends are called Tunnels.
• Solution Sinks are formed by surface dissolution and are more common; when the bottom of a sinkhole forms the roof of an underground void and collapses, it is called a Collapse Sink or Doline.
Stalactites hang as icicles of different diameters from the cave roof—broad at their bases and tapering towards the free ends. Stalagmites rise up from the floor via water dripping from the surface or through the pipe of the stalactite immediately above, taking the shape of a column, a disc, with either a smooth, rounded bulging end or a miniature crater-like depression.
Karst Landforms Matrix
High-Yield UPSC Prelims Reference