Chemical disaggregation of kaolinitic claystones (tonsteins and flint clays)

• Published in: Clays and clay minerals Vol. 50; no. 6; pp. 766 - 770
• Main Authors: Triplehorn, Don M, Bohor, Bruce F, Betterton, William J
• Format: Journal Article
• Language: English
• Published: Boulder, CO Clay Minerals Society 01-12-2002; The Clay Minerals Society
• Subjects: chemical dispersion; chemically precipitated rocks; clastic rocks; clay mineralogy; clay minerals; claystone; dimethyl sulfoxide; Disaggregation; Dmso; Earth sciences; Earth, ocean, space; Exact sciences and technology; flint; Flint Clay; geochemistry; Hydrazine Monohydrate; kaolinite; Kaolinitic Claystone; mineral composition; Mineralogy; Petrology of sedimentary rocks except quaternary rocks; sed rocks, sediments; Sedimentary petrology; Sedimentary rocks; sheet silicates; Silicates; Tonstein; volcanic ash; kaolinite; Flint Clay. Hydrazine Monohydrate; tonstein; sedimentary rocks; claystone; separation; Disaggregation. DMSO; flint clay; sheet silicates; silicates; alteration; clay minerals; dating; Kaolinitic Claystone; clastic rocks
• ISSN: 0009-8604; 1552-8367
• DOI: 10.1346/000986002762090164

The coarse non-clay fraction of many flint-like kaolinitic claystones often contains mineral grains diagnostic of the claystone's origin and, in the case of tonsteins (altered volcanic ashes), may also provide minerals suitable for radiometric dating. Separation of the non-clay mineral fraction is often difficult because flint clays and flint-like clays resist slaking in water and thus are difficult to disaggregate. Chemical disaggregation of resistant kaolinitic claystones may be achieved by immersion in either hydrazine monohydrate or DMSO for periods ranging from one day to several weeks. Generally, hydrazine monohydrate works more quickly and efficiently than DMSO to disaggregate most kaolinitic claystones and flint clays.