Which one of the following is not a process of chemical weathering?

Weathering is classified into three major groups: chemical, physical (mechanical), and biological [1]. Chemical weathering involves the alteration of rock composition through chemical reactions, typically involving water and atmospheric gases. Key processes include solution (dissolution of minerals), carbonation (reaction with carbonic acid), oxidation (reaction with oxygen), and hydrolysis [1]. Solution occurs when minerals dissolve in water, while carbonation specifically targets carbonate minerals like limestone [1]. Oxidation is the reaction of oxygen with minerals, such as iron, to form oxides [2]. In contrast, exfoliation is a physical or mechanical weathering process. It involves the disintegration of rocks without chemical change, often caused by pressure release or thermal expansion, leading to the peeling of outer rock layers. Therefore, exfoliation is not a chemical weathering process.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Weathering > p. 83
2. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 4: Weathering, Mass Movement and Groundwater > CHEMICAL WEATHERING > p. 37