Hodaka Kawahata, Tokyo University, said that the world's oldest stone iron (* 1, Sekizoku) and the world's oldest pottery found at the Odaiyamamoto site in Aomori Prefecture were the coldest in the Japanese archipelago. It was found in a study by a professor at the Atmosphere and Ocean Research Institute.It is said that the climate of the Jomon period at that time was colder than that of the present Konsen region in Hokkaido, and it is thought that marine products were boiled in Jomon pottery and eaten.
東京大学大気海洋研究所によると、川幡教授はアルケノン水温（※2）という手法を用いて本州最北端の下北半島沖で過去2万7,000年の夏の気温と水温を復元した。その結果、温度が最も高かったのは6,670年前の気温20.0度、水温19.4度、最も低かったのは1万5,680年前の気温5.2度、水温8.7度であることが分かった。
At present, Aomori Prefecture has a temperature of 16.7 degrees Celsius and a water temperature of 15.7 degrees Celsius, which was 7 to 11 degrees lower than it is now.The world's oldest stone iron and the world's oldest pottery found at the Odai Yamamoto site are said to have appeared 1 to 6,500 years ago, which is the coldest time.
At this temperature, the fruit of land plants cannot be expected so much due to the influence of cold summer, but it seems that abundant marine products could be collected.Professor Kawabata believes that the Jomon people developed earthenware for boiling marine products, which is consistent with the analysis results of organic matter attached to the earthenware.
* 1 Arrowhead made of stone
* 2 Alkenone water temperature A method of investigating the degree of unsaturation of alkenone, an organic compound biosynthesized by phytoplankton coccolithophores inhabiting the ocean surface, from sediments and investigating past surface water temperatures.
Paper information: [Quaternary Science Reviews] Quantitative reconstruction of temperature at a Jōmon site in the Incipient Jōmon Period in northern Japan and its implications for the production of early pottery and stone arrow heads
