Weathering of granite leads to formation of solid residual minerals and release of some elements as dissolved ions. The elements released are:

Question

Prepp Team · Accepted Answer

Granite Weathering Explained

The weathering of granite involves chemical and physical processes that break down its constituent minerals. Granite is mainly composed of quartz, feldspars (like potassium feldspar and plagioclase), and micas.

Mineral Breakdown and Element Release

Quartz: Highly resistant to chemical weathering, it mostly remains as solid silicon dioxide (SiO₂).
Feldspars: These minerals, particularly alkali feldspars (containing Na and K), undergo hydrolysis. This reaction breaks them down into secondary clay minerals (aluminosilicates) and releases soluble ions like sodium (Na⁺) and potassium (K⁺) into the surrounding water.
Micas: Also weather to form clays, releasing cations like K⁺ and Mg²⁺, and forming hydrated aluminosilicates.
Iron (Fe) and Manganese (Mn): These elements are typically present in smaller amounts or within specific accessory minerals in granite. While they can be released during weathering, often as ions (Fe²⁺, Fe³⁺, Mn²⁺), they are frequently incorporated into secondary minerals or precipitate as oxides/hydroxides, making their release as simple dissolved ions less dominant compared to alkali metals.

Released Elements Focus

The question asks specifically for elements released as dissolved ions. During the weathering of common granite minerals like feldspars, alkali metals such as sodium and potassium are readily liberated as mobile, dissolved ions (Na⁺, K⁺). While silicon (Si) and aluminum (Al) are components of the original minerals and form secondary minerals, their release as simple dissolved ions is less characteristic than the release of Na and K.