Volcanic tuff altered to montmorillonite is called what?

Volcanic tuff altered to montmorillonite is called what?

• A. Kaolinite
• B. Bentonite
• C. Smectite
• D. Illite

Answer: (B)

Volcanic tuff that has been chemically altered to aMontmorillonite-rich clay is known as bentonite. Montmorillonite is a swelling clay in the smectite group, so when volcanic ash (tuff) weatheres and alters to this mineral, the resulting clay deposit is termed bentonite. The name bentonite specifically reflects clays dominated by montmorillonite derived from altered volcanic material. This differs from kaolinite and illite, which form under different weathering conditions, and from the broader smectite group, of which montmorillonite is a member. Bentonite’s swelling and sealing properties come from the montmorillonite layers, making it valuable for drilling fluids and liners.

Volcanic tuff that has been chemically altered to aMontmorillonite-rich clay is known as bentonite. Montmorillonite is a swelling clay in the smectite group, so when volcanic ash (tuff) weatheres and alters to this mineral, the resulting clay deposit is termed bentonite. The name bentonite specifically reflects clays dominated by montmorillonite derived from altered volcanic material. This differs from kaolinite and illite, which form under different weathering conditions, and from the broader smectite group, of which montmorillonite is a member. Bentonite’s swelling and sealing properties come from the montmorillonite layers, making it valuable for drilling fluids and liners.