VOLCANIC ASH - BENTONITE

Description: Bentonite usually forms from the weathering of volcanic ash. Geologically, volcanic ash layers are extremely important in that they provide a contemporaneous time horizon allowing correlation from area to area,

PICT0182 (Large).jpg

Figure 1 - Layers of white Bentonite found near the Denjeck River, Yukon. (Photo 1973)

PICT0181 (Large).jpg

Figure 2 - Close-up of Bentonite viewed in Figure 1. (Photo 1973)

PICT0179 (Large).jpg

Figure 3 - The T-3 Bentonite near Davis Crossroads, Georgia, USA.  Bentonites are commonly difficult to locate due to their soft, crumbly nature that leads to the formation of a soil.  The T-3 Bentonite in the southern Appalachians, however, can be readily located since it is underlain by a resistant Chert formed from the leaching of silica from the Volcanic Ash. 

PICT0178 (Large).jpg

Figure 4 - A close-up view of the contact between the Bentonite (greenish-brown) above and the T-3 Chert (black) below found at Davis Crossroads, Georgia, USA.