What is carbonation in the context of chemical weathering?

In the context of chemical weathering, carbonation refers specifically to the process where carbon dioxide in the atmosphere or soil combines with water to form carbonic acid. This acid increases the acidity of the water, enabling it to dissolve various minerals more effectively. This is particularly significant for carbonate minerals, such as limestone, which can be extensively weathered through this process.

When carbonic acid seeps into cracks and pores of rocks, it can dissolve the calcium carbonate in limestone, leading to the formation of karst landscapes and other geological features. This chemical reaction and the subsequent dissolution of minerals play a crucial role in soil formation and nutrient cycling, ultimately affecting ecosystems. Thus, the correct answer highlights the critical aspect of how acidic water facilitates the breakdown of minerals through chemical reactions, distinguishing carbonation from other processes like mechanical breakdown or nutrient supply through decomposition.