1:45 PM - 3:15 PM
[O11-P23] Petrological study on the lithological origin of the Ueno Three Stele, Yamanoue, and Kanaizawa monument stone materials.
Keywords:Three Stelae of Kozuke Province, Monument of Yamanoue, Monument of Kanaizawa, Karasu River, Kaburagawa River, Pyroxene andesite
1. Background and Purpose of the Study
The kōzuke Sanpi (Three Stelae of Kozuke Province) are the oldest group of stone monuments in Japan, known individually as the Tago Monument, the Kanaizawa Monument, and the Yamanoue Monument (Figure 1). The Yamanoue Monument is located in Yamana-machi, Takasaki City, Gunma Prefecture (Figure 2), and is considered the oldest stone monument in Japan that has survived in a complete form. It is believed to be made from the same type of hard pyroxene andesite natural stone as the Kanaizawa Monument. The dimensions of the Yamanoue Monument are 111 cm in height, 47 cm in width, and 52 cm in thickness (Reference 3). The Kanaizawa Monument, also located in Yamana-machi, Takasaki City, is similarly made of hard pyroxene andesite. Its dimensions are 110 cm in height, 70 cm in width, and 65 cm in thickness.
The area surrounding the Yamanoue and Kanaizawa Monuments is flanked by the Karasu River to the north and the Kabura River to the south. Previous research has suggested that the Yamanoue Monument was transported from the Karasu River, and that both monuments most likely originated from a quarry located south of Suginoki-tōge in Takakawara, Shimonita Town, Kanra District, Gunma Prefecture (References 1 and 2). However, the exact origin of the stones has yet to be confirmed. The purpose of this study is to observe both monuments and collect information that may help identify their origin.
2. Research Methods
Visual rock description and modal analysis will be conducted on the Monument of Yamanoue and the Monument of Kanaizawa. In the modal analysis, eight photos taken from different locations on each of the Monument of Yamanoue and the Monument of Kanaizawa will be examined. Areas without noticeable features will be cropped, and a grid will be applied. The number of intersections where colored minerals overlap will be counted.
3. Results
The Monument of Yamanoue contained more colored minerals, likely pyroxene, than the Monument of Kanaizawa, which displayed more red-colored minerals, likely hematite (Figure 4).
In the modal analysis, 800 intersections were examined per monument. The percentage of intersections containing colored minerals, likely pyroxene, was calculated, and a t-test was performed on the two sets of data. The result was P = 0.0000257908. Since P(T<=t) < 0.05, the null hypothesis that there is no difference in the percentage of colored minerals is rejected. This suggests that there is a significant difference in the proportion of colored minerals between the Monument of Yamanoue and the Monument of Kanaizawa (Figures 3, 5).
4. Discussion
Previous studies have stated that the Monument of Yamanoue and the Monument of Kanaizawa were made from the same source (Reference 1). However, our findings show that the proportion of pyroxene-like colored minerals differs between the two stelae. Additionally, visual observation revealed that Monument of Yamanoue contains more colored minerals, and Monument of Kanaizawa has minerals identified as hematite, which were not observed in the Monument of Yamanoue. Based on these results, we hypothesize that the two stelae were not made from the same rock material. Furthermore, neither Monument of Yamanoue nor Monument of Kanaizawa are made from angular stones, such as those directly cut from an outcrop, but rather appear to be rounded pebbles, suggesting that river cobbles were used. Therefore, we suggest that the origin of the stones may be upstream from the Karasu and Kabura rivers that flow near the monuments.
5. Conclusion
This study primarily compared Monument of Yamanoue and Monument of Kanaizawa . While we were unable to confirm the exact origin of the stones used in the stelae, it was revealed that there is a possibility that different types of rock materials were used, despite previous assumptions that they were made from the same rock. This suggests that the rocks used in the two monuments may have separate origins. Although our research focused on areas surrounding the Karasu and Kabura rivers, it is possible that the stones were transported from other regions, and further research may help pinpoint their origin.
The kōzuke Sanpi (Three Stelae of Kozuke Province) are the oldest group of stone monuments in Japan, known individually as the Tago Monument, the Kanaizawa Monument, and the Yamanoue Monument (Figure 1). The Yamanoue Monument is located in Yamana-machi, Takasaki City, Gunma Prefecture (Figure 2), and is considered the oldest stone monument in Japan that has survived in a complete form. It is believed to be made from the same type of hard pyroxene andesite natural stone as the Kanaizawa Monument. The dimensions of the Yamanoue Monument are 111 cm in height, 47 cm in width, and 52 cm in thickness (Reference 3). The Kanaizawa Monument, also located in Yamana-machi, Takasaki City, is similarly made of hard pyroxene andesite. Its dimensions are 110 cm in height, 70 cm in width, and 65 cm in thickness.
The area surrounding the Yamanoue and Kanaizawa Monuments is flanked by the Karasu River to the north and the Kabura River to the south. Previous research has suggested that the Yamanoue Monument was transported from the Karasu River, and that both monuments most likely originated from a quarry located south of Suginoki-tōge in Takakawara, Shimonita Town, Kanra District, Gunma Prefecture (References 1 and 2). However, the exact origin of the stones has yet to be confirmed. The purpose of this study is to observe both monuments and collect information that may help identify their origin.
2. Research Methods
Visual rock description and modal analysis will be conducted on the Monument of Yamanoue and the Monument of Kanaizawa. In the modal analysis, eight photos taken from different locations on each of the Monument of Yamanoue and the Monument of Kanaizawa will be examined. Areas without noticeable features will be cropped, and a grid will be applied. The number of intersections where colored minerals overlap will be counted.
3. Results
The Monument of Yamanoue contained more colored minerals, likely pyroxene, than the Monument of Kanaizawa, which displayed more red-colored minerals, likely hematite (Figure 4).
In the modal analysis, 800 intersections were examined per monument. The percentage of intersections containing colored minerals, likely pyroxene, was calculated, and a t-test was performed on the two sets of data. The result was P = 0.0000257908. Since P(T<=t) < 0.05, the null hypothesis that there is no difference in the percentage of colored minerals is rejected. This suggests that there is a significant difference in the proportion of colored minerals between the Monument of Yamanoue and the Monument of Kanaizawa (Figures 3, 5).
4. Discussion
Previous studies have stated that the Monument of Yamanoue and the Monument of Kanaizawa were made from the same source (Reference 1). However, our findings show that the proportion of pyroxene-like colored minerals differs between the two stelae. Additionally, visual observation revealed that Monument of Yamanoue contains more colored minerals, and Monument of Kanaizawa has minerals identified as hematite, which were not observed in the Monument of Yamanoue. Based on these results, we hypothesize that the two stelae were not made from the same rock material. Furthermore, neither Monument of Yamanoue nor Monument of Kanaizawa are made from angular stones, such as those directly cut from an outcrop, but rather appear to be rounded pebbles, suggesting that river cobbles were used. Therefore, we suggest that the origin of the stones may be upstream from the Karasu and Kabura rivers that flow near the monuments.
5. Conclusion
This study primarily compared Monument of Yamanoue and Monument of Kanaizawa . While we were unable to confirm the exact origin of the stones used in the stelae, it was revealed that there is a possibility that different types of rock materials were used, despite previous assumptions that they were made from the same rock. This suggests that the rocks used in the two monuments may have separate origins. Although our research focused on areas surrounding the Karasu and Kabura rivers, it is possible that the stones were transported from other regions, and further research may help pinpoint their origin.