10:45 AM - 11:15 AM
[MIS24-05] Provenance of sandstone used for giant stone monument: case study of tombstones in Yamauchi clan feudal cemetery
★Invited Papers
Keywords:sandstone, magnetic susceptibility, feudal cemetery, The Tosa Clan Yamauchi Family
The origin and distribution routes of the stones used in historically and culturally significant stone buildings, or the techniques used to create stone structures, can provide clues to understanding the political, cultural, and economic background of the period. The origin of the stones used in stone buildings can be confirmed in historical records, but there are very few cases where this has been scientifically verified. For this reason, in this study we attempted to use geoscientific methods to identify the origin of the sandstone used in the tombs of the Yamauchi family, who were the lords of the Tosa domain.
The Tosa Clan Yamauchi Family Mausoleum in Kochi City contains the graves of the clan's daimyo (feudal lords) and their families, from the first (who died in 1605) to the sixteenth (who died in 1886). Each grave marker consists of a single stone block over two meters high. Of the 16 generations of feudal lords, all except the first, second, ninth and fifteenth generations were made of white to gray sandstone. In addition, documentary research has shown that the tombstones of the 8th, 11th, and 16th lords came from the Higashi-Morogi area (Kochi City), the tombstone of the 11th lord from the Higashi-Morogi area and the Koudono area (Kochi City), and the tombstone of the 16th lord from the Karyougo area (Aki Ward) (Mochizuki 2023). However, the actual mining sites are unknown.
In this study, we narrowed down the candidate quarry sites through interviews and conducted surveys of the daimyo gravestones and rocks at the quarry sites. The survey work included visual observation, measurement of magnetic susceptibility using a portable magnetic susceptibility meter (KT-10C, Terraplus), measurement of color values using a small colorimeter (Spectro1, Variable), and elemental analysis using a portable X-ray fluorescence analyzer (X-MET8000, Hitachi High-Tech Science).
As a result of the listening survey and on-site inspection, it was found that there was a possibility that sandstone was used in Suzumegamori (Site A), Namura-no-hana (Site B), and the backyard of the Nomoto family in the Koudono area (Site C). As a result of visual observation, a 10mm-wide dark gray vein pattern was developed in the the 8th load and some of the tombstones, and the same vein pattern was confirmed in the boulder at Site A. The results of the magnetic susceptibility measurements showed that most of the 11th to 16th generation sandstone daimyo tombstones had magnetic susceptibility values of 0.17×10-3 to 0.20×10-3 SI, but the 11th generation tombstone had a slightly higher value (0.26×10-3 SI), and the 16th generation tombstone had a slightly lower value (0.06×10-3 SI). In addition, the pedestal of the 11th tombstone showed a slightly lower value than the main body. On the other hand, the sandstone at the outcrops at sites A to C showed values of 0.18×10-3 to 0.20×10-3 SI, with no significant differences observed. In addition, the sandstone at the Karyougo area all showed lower values than the sandstone at sites A to C (0.08×10-3 to 0.14×10-3 SI).
From the above, it appears that the sandstone used for the tombstones of many daimyo was quarried in the Haruno district of Kochi Prefecture, the same place where the tombstone of the 8th daimyo was quarried. In addition, it is possible that the main body of the 11th daimyo's tombstone was made of rocks collected in Koudono, and the base was made of rocks collected in Higashi-Morogi. The magnetic susceptibility results suggest that the 16th daimyo's gravestone was made of stone from a different quarry than the other gravestones, but it is not possible to say for certain at this point whether it was made of sandstone from Karyou-go. We will continue to investigate based on the results of the color value and element concentration measurements.
The Tosa Clan Yamauchi Family Mausoleum in Kochi City contains the graves of the clan's daimyo (feudal lords) and their families, from the first (who died in 1605) to the sixteenth (who died in 1886). Each grave marker consists of a single stone block over two meters high. Of the 16 generations of feudal lords, all except the first, second, ninth and fifteenth generations were made of white to gray sandstone. In addition, documentary research has shown that the tombstones of the 8th, 11th, and 16th lords came from the Higashi-Morogi area (Kochi City), the tombstone of the 11th lord from the Higashi-Morogi area and the Koudono area (Kochi City), and the tombstone of the 16th lord from the Karyougo area (Aki Ward) (Mochizuki 2023). However, the actual mining sites are unknown.
In this study, we narrowed down the candidate quarry sites through interviews and conducted surveys of the daimyo gravestones and rocks at the quarry sites. The survey work included visual observation, measurement of magnetic susceptibility using a portable magnetic susceptibility meter (KT-10C, Terraplus), measurement of color values using a small colorimeter (Spectro1, Variable), and elemental analysis using a portable X-ray fluorescence analyzer (X-MET8000, Hitachi High-Tech Science).
As a result of the listening survey and on-site inspection, it was found that there was a possibility that sandstone was used in Suzumegamori (Site A), Namura-no-hana (Site B), and the backyard of the Nomoto family in the Koudono area (Site C). As a result of visual observation, a 10mm-wide dark gray vein pattern was developed in the the 8th load and some of the tombstones, and the same vein pattern was confirmed in the boulder at Site A. The results of the magnetic susceptibility measurements showed that most of the 11th to 16th generation sandstone daimyo tombstones had magnetic susceptibility values of 0.17×10-3 to 0.20×10-3 SI, but the 11th generation tombstone had a slightly higher value (0.26×10-3 SI), and the 16th generation tombstone had a slightly lower value (0.06×10-3 SI). In addition, the pedestal of the 11th tombstone showed a slightly lower value than the main body. On the other hand, the sandstone at the outcrops at sites A to C showed values of 0.18×10-3 to 0.20×10-3 SI, with no significant differences observed. In addition, the sandstone at the Karyougo area all showed lower values than the sandstone at sites A to C (0.08×10-3 to 0.14×10-3 SI).
From the above, it appears that the sandstone used for the tombstones of many daimyo was quarried in the Haruno district of Kochi Prefecture, the same place where the tombstone of the 8th daimyo was quarried. In addition, it is possible that the main body of the 11th daimyo's tombstone was made of rocks collected in Koudono, and the base was made of rocks collected in Higashi-Morogi. The magnetic susceptibility results suggest that the 16th daimyo's gravestone was made of stone from a different quarry than the other gravestones, but it is not possible to say for certain at this point whether it was made of sandstone from Karyou-go. We will continue to investigate based on the results of the color value and element concentration measurements.