How does rainwater dissolve carboniferous limestone to create pavements, swallow holes and caves?
The formation of features in upland limestone (karst) landscapes - limestone pavement with clints and grikes, swallow holes, caverns with stalactites and stalagmites, and intermittent drainage - by chemical weathering and solution.
An SQA National 5 Geography answer on upland limestone landscapes, explaining how chemical weathering and solution form limestone pavements with clints and grikes, swallow holes, underground caverns with stalactites and stalagmites, and intermittent drainage, with named examples.
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What this dot point is asking
The SQA wants you to explain how rainwater dissolves carboniferous limestone to create a distinctive karst landscape, and to describe and explain the formation of limestone pavements (clints and grikes), swallow holes, underground caverns with stalactites and stalagmites, and intermittent (disappearing) drainage. You should support an answer with a labelled diagram and a named example.
Why limestone behaves differently
Surface features: limestone pavements
When glaciers scraped the soil off the limestone uplands, they left bare rock exposed. Rainwater then attacked the surface:
- Acidic rainwater runs into the joints and dissolves the limestone along them.
- Over thousands of years the joints widen into deep grooves called grikes.
- The flat-topped blocks of limestone left between the grikes are called clints.
The whole flat, bare surface of clints and grikes is a limestone pavement (for example above Malham in the Yorkshire Dales).
Drainage features: swallow holes and intermittent streams
Because water sinks into limestone, the surface is unusually dry:
- A surface stream flowing off neighbouring impermeable rock reaches the limestone and disappears underground down a swallow hole (also called a sink or pot hole).
- The water flows through underground passages and caves, sometimes reappearing at a spring lower down where the limestone meets impermeable rock.
- This on-and-off pattern, where streams flow on the surface then vanish, is called intermittent drainage.
Underground features: caverns, stalactites and stalagmites
Underground, water rich in dissolved calcium carbonate drips into caves. As each drop evaporates a little, it leaves a tiny deposit of calcite:
Examples in context
Example 1. Malham, Yorkshire Dales. Above Malham Cove sits a famous limestone pavement of clints and grikes, formed where glaciers stripped the soil and acidic rain dissolved the joints, the standard UK teaching site for karst.
Example 2. Gaping Gill, Yorkshire. A swallow hole where Fell Beck plunges underground into one of Britain's largest cave chambers, showing intermittent drainage and underground caverns in action.
Try this
Q1. Name the deep grooves dissolved into a limestone pavement. [1 mark]
- Cue. Grikes (the blocks between them are clints).
Q2. State the type of weathering that shapes limestone landscapes. [1 mark]
- Cue. Chemical weathering (carbonation or solution).
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
SQA N5 style4 marksExplain the formation of a limestone pavement.Show worked answer →
A 4-mark "Explain the formation" answer needs linked process points, so build the pavement from the rock properties to the grooves.
Carboniferous limestone is a hard rock made of calcium carbonate, with many joints and bedding planes (lines of weakness).
Rainwater is a weak carbonic acid because it absorbs carbon dioxide from the air. When it lands on bare limestone it slowly dissolves the rock along the joints. This is chemical weathering, called carbonation or solution.
Over a long time the joints are widened into deep grooves called grikes, leaving blocks of limestone between them called clints.
The flat exposed surface of blocks and grooves is a limestone pavement, often left bare by glaciers stripping off the soil. Markers reward the acid rainwater, the dissolving along joints, and naming clints and grikes.
SQA N5 style4 marksDescribe the differences in drainage between a limestone area and an area of impermeable rock.Show worked answer →
This is a compare question, so each point must mention both areas to score.
In a limestone area there are very few surface streams, because water sinks underground through the joints, while an area of impermeable rock has many surface streams and rivers that cannot sink in.
In limestone, surface streams disappear down swallow holes (sinks) where they meet the limestone, then flow through underground caves, whereas in impermeable rock the streams stay on the surface throughout.
Limestone areas have a dry, almost stream-free surface (intermittent drainage), while impermeable areas stay wet with bogs and pools. Markers reward each clear contrast, naming swallow holes and underground flow against continuous surface flow.
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Sources & how we know this
- National 5 Geography Course Specification (C833 75) — SQA (2025)
- National 5 Geography - Course overview and resources — SQA (2025)