A Regularly Interstratified Mineral of Sericite and Swelling-layer Derived from 2M type Sericite in the Landslide Deposits, Kochi Prefecture Central Shikoku

KIMBARA Keiji, OHKUBO Taiji

doi:10.11362/jcssjnendokagaku1961.16.1

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Other Title

２Ｍ型セリサイトより生成した地すべり土中のセリサイト／膨潤層規則型混合層鉱物
2Mガタセリサイトヨリセイセイシタジスベリドチュウノセリサイト

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Description

Many active landslides are developed in the Sambagawa metamorphic terrain at Motoyama, Kochi Prefecture, central Shikoku. The clay minerals such as sericite, interstratified clay mineral and kaolin together with gibbsite were identified in the debris of landslide deposits at Yoshinobu and Furuta districts. Under the microscope, the whity-debris shows a texture of albitophyre. A large amount of sericite having 2M polytype in association with kaolin and interstratified mineral occurs in the groundmass and replacing albite crystals. The sericite may have been formed by hydrothermal alteration. A. clayey-debris is mainly composed of an interstratified mineral in association with sericite, kaolin and gibbsite. X-ray analysis indicates the interstratified mineral is a regulerly interstratification of sericite (0.55) and swellinglayer (0.45). It may be concluded the sericite converts into kaolin and/or gibbsite through interstratified mineral of sericite and swelling-layer by weathering closely related to activity of landslides developed in this area.

Journal

Journal of the Clay Science Society of Japan (in Japanese)

Journal of the Clay Science Society of Japan (in Japanese) 16 (1), 1-9, 1976

The Clay Science Society of Japan