2024-03-29T02:22:13Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00012814
2023-01-16T03:59:39Z
879:1183:1184:1312
A weathering assessment of calcareous sandstone using radiocarbon : A natural analogue study for weathering of concrete construction
石灰質砂岩の炭素14 を指標とする風化評価 : コンクリート風化のナチュラルアナログ研究として
南, 雅代
82796
池田, 晃子
82797
吉田, 英一
82798
田中, 剛
82799
Minami, Masayo
82800
Ikeda, Akiko
82801
Yoshida, Hidekazu
82802
Tanaka, Tsuyoshi
82803
2009-03
Weathering rinds in two Triassic calcareous sandstones collected from Tatehama and Namiita at the Sanriku seashore, northeast Japan, were investigated to clarify the process of elemental migration, especially modem radiocarbon (^<14>C) accumulation caused by atmospheric CO2 during chemical weathering. Major element and carbon concentrations together with ^<14>C abundances were measured across weathering rinds of the sandstones. Specific depletion of calcium and carbon concentrations, and enrichment of iron concentration were observed in the weathering rinds for the both calcareous sandstones. The result indicates that calcareous phase in weathering rinds has been leached, and that ferrous ion has been accumulated in the rims by oxidization after migration under reducing subsurface during chemical weathering. It is noted that the Tatehama and Namiita sandstones have different behavior of migration for some elements such as calcium and magnesium in the extreme rims: a little enrichment and gradual depletion for the Tatehama and Namiita samplesラrespectively. The difference might be due to seawater-rock interaction because the Tatehama sample occurs near seashore lapped by wave and the Namiita sample does not. On the other hand, the both sandstones show the same ^<14>C accumulation behavior in weathering rinds. ^<14>C was not detected in the fresh fractions of the calcareous sandstones, due to ^<14>C-free (dead) carbon contained in a fresh Triassic limestone, while modem ^<14>C was detected in the weathering rinds. The modem ^<14>C could be originated from atmospheric CO2. From this study, ^<14>C is found to be a sensitive and general index of weathering of calcareous stones. Therefore, ^<14>C could be used as a sensitive index of concrete weathering.
第21回名古屋大学年代測定総合研究センターシンポジウム平成20(2008)年度報告
departmental bulletin paper
名古屋大学年代測定資料研究センター
2009-03
名古屋大学加速器質量分析計業績報告書
20
71
80
jpn