About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

CSPG Bulletin

Abstract

Journal of the Alberta Society of Petroleum Geologists
Vol. 7 (1959), No. 1. (January), Pages 13-15

Bentonite?

Karl H. Wolf

ABSTRACT

It is suggested that in defining bentonites the definition of Pettijohn (1957) be accepted with the following addition: "Bentonite is composed mainly of claylike material which has been formed by the alteration of volcanic tuff and ash at the site of deposition."

Because the major component of the clay is usually montmorillonite, which breaks down into flakes or colloidal particles, bentonites have been identified by using the "expansion" test. This procedure is very unreliable for the following reasons: 1, different types of montmorillonite expand at varying rates or not at all; 2, montmorillonite may be formed independent of any volcanic material, or may be derived from an older volcanic rock; 3, the alteration products of volcanic deposits depend on many factors and need not be montmorillonite; 4, montmorillonite is very sensitive to environments and undergoes changes very readily.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24