Karst topography, with features such as sinkholes, caves and disappearing streams, is primarily produced by which type of weathering process?

Introduction / Context:
This question examines your understanding of geomorphology, specifically how different types of weathering processes shape the earth surface. Karst topography is a distinctive landscape formed mainly in regions with soluble rocks such as limestone. Recognising the dominant weathering process that produces karst landforms is a key concept in physical geography.

Given Data / Assumptions:

• The landform type mentioned is karst topography.
• Typical features of karst include sinkholes, caves, disappearing streams and underground drainage.
• The options list different kinds of weathering: chemical, physical, biological, glacial and aeolian.
• The question asks which type of weathering is primarily responsible for creating karst landscapes.

Concept / Approach:
Karst topography develops where water, often slightly acidic due to dissolved carbon dioxide, reacts with soluble rocks such as limestone, dolomite or gypsum. This process is a classic example of chemical weathering, where minerals in rocks are dissolved or altered in composition. Over time, dissolving and enlarging joints and fractures create underground cavities, caves and sinkholes. While physical and biological processes may play minor supporting roles, the main driver is chemical dissolution.

Step-by-Step Solution:
Step 1: Recall the definition of karst topography as a landscape dominated by solution features in limestone regions. Step 2: Understand that solution features arise when slightly acidic water reacts chemically with the rock and dissolves it. Step 3: Classify this process as chemical weathering, since it changes the chemical composition of the rock. Step 4: Compare this with physical weathering, which mainly breaks rock into pieces without changing its chemical composition. Step 5: Conclude that chemical weathering is the primary process forming karst topography and select it as the correct answer.

Verification / Alternative check:
To verify, check any standard physical geography textbook under topics such as weathering, mass movement or landforms. The section on karst or limestone topography will explain how carbonic acid in groundwater dissolves calcium carbonate in limestone. Diagrams often show rainwater passing through soil, becoming mildly acidic and then slowly dissolving limestone, forming caves and sinkholes. These explanations consistently describe the process as chemical weathering by solution.

Why Other Options Are Wrong:
Physical weathering involves mechanical breakdown through processes such as freeze thaw, exfoliation or abrasion, which do not primarily create extensive cave systems in limestone. Biological weathering occurs when plants, animals or microorganisms contribute to rock breakdown, but this is not the main mechanism for karst formation. Glacial weathering is associated with ice action and erosion in cold regions, not with limestone solution landscapes. Aeolian weathering or wind related processes shape deserts and sand dunes rather than underground drainage systems and sinkholes.

Common Pitfalls:
A common mistake is to choose both chemical and physical weathering together when questions are worded differently, or to think that mechanical erosion by running water is responsible. Another pitfall is to confuse the erosion of rock material transported by rivers with the chemical dissolution that creates underground voids. To avoid errors, always associate karst landscapes with solution action in limestone and remember that this is a classic example of chemical weathering.

Final Answer:
Chemical weathering