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Characteristics of Salt Weathering and Environmental Variation on the Usuki Stone Buddha Statues in Oita, Japan
일본 오이타현 우스키 마애불상군의 환경변화와 염풍화 특성
Econ. Environ. Geol. 2020 Dec;53(6):677-85
Published online December 31, 2020;
Copyright © 2020 the Korean society of economic and environmental gelology.

Ji Hyun Cho1 and Chan Hee Lee2*
조지현1 · 이찬희2*

1Buyeo National Research Institute of Cultural Heritage, Buyeo, 33123, Korea
2Department of Cultural Heritage Conservation Sciences, Kongju National University, Gongju, 32588, Korea
1국립부여문화재연구소, 2공주대학교 문화재보존과학과
Received September 25, 2020; Revised October 27, 2020; Accepted October 31, 2020.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
The host rock of the Usuki Stone Buddha Statues is dark gray welded tuff involved the Aso-4 pyroclastic flow sediments. This Buddha Statues are processing chlorosis from rainfall flowing above and underground water which were urgently needed for conservation measurement. White precipitates, the main source of salt weathering, on the surface of the Buddha Statues are mainly consisted of thenardite, gypsum and dolomite. Extraction experiment result shows that thenardite was dissolved at the beginning of stirring and then redissolved after 4 hours, and gypsum was detected until stirring for 2 hours, and then dissolved after stirring for 4 hours. As a result of monitoring the microclimate environment for 11 months to determine the recrystallization environment of white precipitates, the phase transition between thenadite and mirabilite appears widely in spring, and is maintained in an aqueous solution due to high temperatures in summer and fall. In winter, mirabilite is shown the widest by decreasing temperature. Therefore we requires details monitoring for blocking water transfer port and solved humidity environment in shelter.
Keywords : Usuki Stone Buddha Statues, tuff, salt weathering, thenardite, microclimate


December 2020, 53 (6)