Smectite in Marine Quick-Clays of Japan

Kazuhiko Egashira and Masami Ohtsubo
Faculty of Agriculture, Kyushu University 46, Fukuoka 812, Japan

Abstract: Clayey sediments of marine origin having sensitivities (ratio of undisturbed to remolded shear strength) as high as 1000 at a reduced salt concentration are found around Ariake Bay, Kyushu, Japan. The clay fraction of the sediments contains smectite as a principal mineral (33–42%) in contrast to the illitic composition of most previously described quick-clays. However, this smectite is a low-swelling type, and the Na-form expands only to about the same extent as the Ca-form and gives a sediment volume almost equal to that of the Ca-clay. This low-swelling smectite appears to consist of packets of unit layers even after saturation with Na, and thus reacts like the kaolinite or illite of conventional quick-clays.

Key Words: Japan • Marine • Quick-clay • Smectite • Swelling

Clays and Clay Minerals; August 1982 v. 30; no. 4; p. 275-280; DOI: 10.1346/CCMN.1982.0300404
© 1982, The Clay Minerals Society
Clay Minerals Society (www.clays.org)