著者

柚原 雅樹 鮎沢 潤 大平 寛人 西 奈保子 田口 幸洋 加々美 寛雄

出版者

日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.34, no.6, pp.275-287, 2005-11-30

被引用文献数

3 5

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The Cretaceous granitic rocks, the Kitazaki Tonalite and Shikanoshima Granodiorite, and veneer Oligocene sedimentary rocks, the Tsuyazaki Formation, are distributed in the Watari Peninsula, Fukuoka Prefecture. There are mineral veins composed by calcite and zeolites in those rocks. Rb-Sr, and fission track geochronological analyses were carried out for granitic rocks, in order to determine the cooling process of granitic rocks and timing of hydrothermal activity. Biotite and felsic fraction separated from the Kitazaki Tonalite and Shikanoshima Granodiorite give Rb-Sr isochron age of 108.6 ± 2.5 Ma and 107.0 ± 0.7 Ma, respectively. Fission track ages from the Kitazaki Tonalite are 97 Ma (titanite), 89-88 Ma (zircon), 14 Ma (apatite). Fission track ages from the Shikanoshima Granodiorite are 95 Ma (titanite), 87-84 Ma (zircon), 15 Ma (apatite). Fission track ages of apatite from granitic rocks are younger than the Tsuyazaki Formation, which suggests a thermal event at about 15 Ma to reset the fission track apatite age. The homogenization temperature of fluid inclusions in calcite are 89-111 °C (Kitazaki Tonalite), 95-118 °C (Shikanoshima Granodiorite) and 85-91 °C (Tsuyazaki Formation). Sr isotopic compositions of calcite and zeolites in granitic rocks and Tsuyazaki Formation are overlap with one another. These data suggest that vein minerals in granitic rocks and zeolites and calcite in the IC Member of the Tsuyazaki Formation were formed by a series of hydrothermal activity at about 15 Ma.

著者

木村 靖幸 鮎沢 潤 佐々木 和久 Kimura Yasuyuki Aizawa Jun Sasaki Kazuhisa

出版者

福岡大学研究推進部

雑誌

福岡大学理学集報 = Fukuoka University Science Reports (ISSN:0386118X)

巻号頁・発行日

vol.35, no.1, pp.31-40, 2005-03

著者

鮎沢 潤

出版者

The Sedimentological Society of Japan

雑誌

堆積学研究会報 (ISSN:18844715)

巻号頁・発行日

vol.35, no.35, pp.77-81, 1991-11-01 (Released:2010-05-27)

参考文献数

19

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A simple and practical method for estimating salinity is described in this paper based on pyrite (iron disulfide) content in carbonaceous materials by using a reflected microscope. The pyrite content is defined as the proportion of carbonaceous particles which contain pyrite in one hundred carbonaceous particles under microscope.The presence of pyrite in organic sedimentary rocks has been considered to be a result of sulfate from sea water, iron from hinterland, and carbonaceous materials as a reductant in coal swamp.Stratigraphic variations of pyrite content by this method were measured in four areas of Southwest Japan. The pyrite content in three Tertiary areas is in accordance with aquatic environments as previously reported. However, no correlation was observed between pyrtite content and estimated aquatic environments in the Omine coalfield where iron content varies considerably. This method will be employed as a useful tool to investigate sedimentary environments.