Name one example of a karst landscape - Leaving Cert Geography - Question 3B - 2020

A common surface feature in karst landscapes is a sinkhole.

To explain its formation:

1. Feature named: Sinkhole.
2. Diagram: The diagram should illustrate a typical sinkhole, showing overlying layers of soil and the exposed limestone below.
   • Aspect 1: The initial process begins with the dissolution of limestone by slightly acidic rainwater, creating underground cavities over time due to chemical erosion.
   • Aspect 2: Eventually, these cavities grow larger. When their ceilings can no longer support the weight of the overlying material, they collapse, forming a sinkhole.
3. Formation explained: The dissolution of limestone occurs as rainwater absorbs carbon dioxide from the atmosphere and soil, becoming carbonic acid, which reacts with the calcium carbonate in limestone, leading to erosion and cavity formation.

An important underground feature in karst landscapes is a stalactite.

To explain its formation:

1. Feature named: Stalactite.
2. Diagram: The diagram should depict a cave with stalactites hanging from the ceiling, illustrating the dripping water and mineral deposits.
   • Aspect 1: Water drips from the cave ceiling as it seeps through the cracks and fissures in the rock, carrying dissolved minerals, particularly calcium carbonate.
   • Aspect 2: When this water evaporates, it leaves behind mineral deposits that gradually accumulate and form stalactites hanging from the ceiling of the cave.
3. Formation explained: Over time, with continued dripping and evaporation, the stalactite grows longer as more minerals are deposited, contributing to the typical formations found in limestone caves.