Consider the following statements with reference to salt weathering : 1. Salts in rocks expand due to thermal action, hydration and crystallization. 2. Salts like calcium, sodium, magnesium and barium have a tendency to expand. 3. Salt weathering is a typical example of chemical weathering. Which of the statements given above is/are correct?

Salt weathering is a form of physical (mechanical) weathering, not chemical weathering, as it involves the disintegration of rocks through molecular stresses rather than chemical decomposition [2]. Statement 1 is correct because salts within rock pores expand due to three primary mechanisms: thermal expansion (when subjected to high temperatures), hydration (taking up water), and crystallization (growth of crystals from saline solutions) [4]. Statement 2 is correct as salts of calcium, sodium, magnesium, potassium, and barium have a high tendency to expand through these processes [3]. While hydration involves a chemical addition of water, its primary effect in salt weathering is the creation of physical pressure and volume changes that lead to granular disintegration or exfoliation [4]. Therefore, salt weathering is categorized as a physical weathering process [2].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Salt Weathering > p. 85
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Physical Weathering Processes > p. 83
3. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Hydration > p. 91
4. [3] NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > MODE OF OCCURRENCE OF MINERALS > p. 106