Limestone

What percentage of Jamaica is limestone

70%

Describe three different features of limestone

• made mainly of calcium carbonate

• weathered by carbonation

• Permeable rock

Uses of limestone

• extract fresh groundwater from limestone

• main raw material for manufacturing cement

• crushed to make aggregate for construction industry

• Cut into blocks, used as building material

Why is limestone vulnerable / susceptible?

Limestone is vulnerable or susceptible because of its chemical makeup and open structure make it especially prone to weathering and erosion in humid or rainy environments.

Chemical structures containing calcium carbonate content, well a well‑jointed structure, and is permeable and porous

What is the 3rd most common mineral in the Earth’s crust

Calcite

Describe calcite

• Crystal-like appearance

• form crystals in a wide variety of shapes and colors

• Calcite, an extremely abundant mineral composed of calcium carbonate (CaCO3)

Explain the process of carbonation with limestone

• Carbonation is a form of chemical weathering in limestone.

• Rain in the atmosphere absorb CO2 —> produces weak carbonic acid ( H2CO3)

• Upon contact with limestone, it react with calcium carbonate mineral (CaCO3)

• The reaction produces calcium bicarbonate (Ca(HCO3)2

  this is soluble and will easily be removed by water creating openings in limestone rocks

Carbonation on limestone equation (Chemical weathering process)

What is created since limestone is permeable

Because limestone is permeable, water seeps through cracks instead of flowing on the surface, creating underground drainage and few surface rivers

Define “Karst Topography”

Kart Topography is the resultant features formed in limestone from the process of Carbonation

SURFACE FEATURES

Limestone pavement (Clints and Grykes)

Definition: A surface of exposed limestone rock divided into blocks (clints) and cracks (grykes).

Formation: Rainwater collects in joints and dissolves the rock by carbonation, widening cracks into grykes and leaving raised blocks called clints.

SURFACE FEATURE (SURFACE DEPRESSION)

Cockpit

Formation: Continuous chemical weathering enlarges sinkholes until they merge, forming a series of enclosed basins - common in Jamaica's Cockpit Country.

Cockpit

• cockpit country in Jamaica made of pure white limestone crossed by joints and faults

• Joints and faults intersect, rapid weathering form star-shaped depression

• Small conical hill remain away from joints

• Where jointing is regular hills are arranged in rows

SURFACE FEATURE (SURFACE DEPRESSION)

Swallow hole / Sinkhole

Definition: A hole or depression where a surface stream disappears underground.

Formation: Carbonation enlarges cracks until the roof collapses or water erodes downward, allowing rivers to "swallow" into underground channels.

SURFACE FEATURE (SURFACE DEPRESSION)

Doline

Definition: A small depression formed by solution of limestone

Formation: Acidic water dissolves limestone below the surface, creating a cavity that eventually collapses.

Doline

• Collapse dolines are formed when a cave roof falls in

• Solution dolines are formed where there are many joints and fissures leading to rapid weathering

• When a doline is lined with clay, a small lake may form

SURFACE FEATURE (SURFACE DEPRESSION)

Polje

Definition: A large, flat-bottomed depression often with temporary lakes.

Formation: Several dolines join together and widen through erosion and collapse, forming a broad basin.

SURFACE FEATURE (SURFACE DEPRESSION)

Uvala

Definition: A large irregular hollow formed by the merging of smaller dolines.

Formation: Continuous dissolution and collapse of limestone cause several dolines to combine into one large depression.

UNDERGROUND FEATURES

Cave

Definition: A natural underground chamber formed in limestone.

Formation: Rainwater seeps through cracks and dissolves limestone along joints and bedding planes, enlarging them into tunnels and chambers.

UNDERGROUND FEATURES

Stalactite and Stalagmite

Definition: Stalactites hang from cave ceilings; stalagmites rise from cave floors.

Formation: Water dripping from the cave roof leaves behind calcium carbonate deposits - stalactites grow downward, stalagmites upward.

UNDERGROUND FEATURES

Pillar

Definition: A column formed when a stalactite and stalagmite join together.

Formation: Continuous deposition of calcium carbonate connects the two features over time.

UNDERGROUND FEATURES

Underground river

Definition: A stream that flows through limestone caves and channels beneath the surface.

Formation: Surface water enters swallow holes and travels through underground passages dissolved by carbonation.

What are the above ground features

Limestone pavement

cockpits

sink holes/swallow holes

dolines

polje

uvala

What are the underground features

caves

stalagmite and stalactite

pillar

underground rivers

Caves and underground drainage

Harrison’s Cave