Detailed analysis of production area of earthenware using detrital zircon dating: Evaluation as an analytical tool for ancient material flow

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18381
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 3:History, archaeology, museology, and related fields
• Research Institution: Kyushu University
• Principal Investigator: Nakano Nobuhiko 九州大学, 比較社会文化研究院, 准教授 (20452790)
• Co-Investigator(Kenkyū-buntansha): 田尻 義了 九州大学, 比較社会文化研究院, 准教授 (50457420)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: ジルコン / 弥生土器 / 須恵器 / 粘土 / 混和材 / U-Pb年代

Outline of Final Research Achievements

This research aims to apply “spot dating method for zircon”, the greatest paradigm shift in modern geology, to earthenware vessels and establish it as the most advanced analytical method in archaeology. Yayoi pottery and Sue ware excavated from the Chikushi area sites were used in this research. Additionally, rocks, clay, and river sand collected from the area around the site were also used. The amount of zircon grains included in the pottery varied according to the material. For the Yayoi pottery from this site, it was estimated that about 10 grams were sufficient for analysis using this method. The obtained U-Pb ages indicate that the zircon in the pottery is not from a mineral admixture but from the clay itself, and the probability density curves of the ages from the pottery are in good agreement with those from the clay.

Free Research Field

地球科学

Academic Significance and Societal Importance of the Research Achievements

これまでの土器の製作地や粘土の原産地の最も精密な解析手法として，土器の化学組成の測定，いわゆる胎土分析がある．しかしながら，土器の原材料である胎土は，粘土と混和材から構成されており，胎土の化学組成は粘土の化学組成と一致せず，さらに混和材と粘土の割合の変化による組成変動の影響を受けるため，直接的な対比が困難であった．一方で，本研究から得られたジルコンを用いた解析結果は，土器と粘土を直接的に対比することが可能であり，起源の異なる土器片を明確に抽出することが可能であるとともに，その流通元についても遺跡周辺に分布する岩石中のジルコン年代と比較することで極めて正確に解析し，説得力あるデータを提供できる．