西会津地域における西黒沢階--女川階の泥質岩に含まれるホウ素-ホウ素含量の層序的分布と古環境の関係-
1973 年 38 巻 1 号 p. 17-25
詳細
1973 年 38 巻 1 号 p. 17-25
The vertical distribution of boron has been investigated in marine mudstones sampled in stratigraphic drill cores in the western Aizu district, Fukushima Prefecture, Northeastern Japan. Organic carbon and K2O content were also determined in order to examine a possible interrelationship of these with the distribution of boron.
Forty six core samples were collected which are correlated with the Globorotaria-Hopkinsina zonule of the Nishikurosawa stage and Spirosigmoilinella zonule of the Onnagawa stage of Middle Miocene age. Boron was determined spectrophotometrically after decomposing powdered samples in a mixture of sulfuric and hydrofluoric acids and extracting the methylene blue-tetrafluoroborate complex with dichloroethane. The analytical results show that within the range tested the boron content decreases stratigraphically from the lower bed (Nishikurosawa stage) to the upper one (Onnagawa stage). The potential use of boron in conjuction with other parameters for a paleoenvironmental analysis is discussed.
