Deterioration of Archaeological Objects in Burial Environment

1987 Fiscal Year Final Research Report Summary

• Project/Area Number: 60300026
• Research Category: Grant-in-Aid for Co-operative Research (A)
• Allocation Type: Single-year Grants
• Research Field: 広領域
• Research Institution: Tokyo National Research Institute of Cultural Properties
• Principal Investigator: KADOKURA Takeo Tokyo Nat'l Research Institute of Cultural Properties Dept. of Conservation Science, Scnior Researcher, 保存科学部, 主任研究官 (10000457)
• Co-Investigator(Kenkyū-buntansha): MACHIDA Akio Nara National Institute of Cultural Properties Dept. of Heijo Palace Site Excava, 平城宮跡田掘調査部, 部長 (90000471) ; FUJIWARA Kitao Hiroshima University Dept. Of Integrated Arts and Science, Professor, 総合科学部, 助教授 (90090521) ; TAKEDA Masuo Toho University Dept. of Science, Professor, 理学部, 教授 (80011633) ; KOBAYASHI Takaaki tokyo Institute of Technology Graduate School at Nagastuta, Professor, 大学院総合理工学研究科, 助教授 (90005984) ; ICHIKUNI Masami Tokyo Institute of Technology Graduate School at Nagastuta, Progessor, 大学院総合理工学研究科, 教授 (20005804)
• Project Period (FY): 1985 – 1987
• Keywords: Archaeological Objects Made of Metal (Bronze, Iron) / Burial Environment / Phenomena of Deterioration / Corrosive Formation / 物質移動

Research Abstract

We noticed such phenomena of deterioration as elusion and settling of chemical elements on archaeological objects made of metal in burial environment. So, we checked the behavior of metal ions by collecting the following samples: 1. Existence of constituency elements of bronze in corrosion layers of iron objects in ruins, where both the iron and bronze objects are unearthed. 2. Migration of constituency elements in soil layers after unearthing the bronze objects. 3. Chemical changes of conditions of underwater burial environment. With regard to the Study 1, settling of copper and tin in corrosion layers has been observed; namely, copper in the form of basic copper carbonate, and tin in the form of stannous oxide were confirmed.
with regard to the Study 2, based on the estimation of density of metal elements in soil (samples taken vertically and vertically from the archaeological objects), we tried to confirm the characteristics of differences of behavior of chemical elements, and migration by measuring distances between the archaeological objects categorically, but we found it difficult to confirm the tendency, due to the number of samples taken during these three years, and due to the composition and grain sizes of soil.
As for 1,2, chances of obtaining samples are limited, and it is hard to give them forms for analysis (EP MA, XF, ESCA), and is harder to improve accuracy of estimation.
We wil try to collect more samples, and check into ways to improve estimation and preparation of samples, and continue the study by reforming the project team in the next term.