著者

硬砂団体研究グループ

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.38, no.1, pp.17-30, 1984-01-25 (Released:2017-07-26)

被引用文献数

1

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Katazuna Bed found in a scattered pattern around the Omiya Upland is very indurated as compared with other Quaternary sand deposits. Its stratigraphy and sedimentological properties are examinated and discribed. The results are summerized as followings. 1) Katazuna Bed distributes in slightly high areas in comparison with the surroundness, and occurs in a thin ribbon or pod form with less than 2 m in thickness, 0.7 to 2km in width, and 2 to 5 km in length, and elongated in NNW to SSE. 2) Katazuna Bed covers the tuffaceous sand "Nukazuna Bed" conformably which is deposited under the fresh water conditions and is also covered conformably by upper Shimosueyoshi Loam formation composed of air fall deposits. Katazuna Bed is deposited about the fall stage of "Kuriyokan Pumice" (: KuP.). 3) Katazuna Bed is composed of well sorted sand grains and has white tubular materials composed of alophen clay with 2 or 3 mm in diameter, and may have been indurated by imogolite as cement materials. Based on above-mentioned results, the sedimentary environment of Katazuna Bed is in-ferred as followings. 4) Katazuna Bed is formed as the result of the regression of Paleo-Tokyo Bay and the bed is important as an environmental indicator of the time. We think that in the central part of the Kanto Plain the prevailing winds transported sand grains composing Nukazuna Bed, and formed the Katazuna Bed as small river dunes or thin sand layers.