Old Sand Dunes

...Coastal sand dunes formed in the Holocene are distributed on many sandy coasts in Japan, and their formation period is divided into two periods. The old sand dunes were formed mainly from the early to late Jomon period (6,500 to 3,000 years ago), and the new sand dunes were formed after the Kofun period (after 1,800 years ago). Between these periods, there is a period when the sand dunes were covered with vegetation for over a thousand years, and a soil layer several tens of centimeters thick called the Crossna layer was formed. Many cultural artifacts, such as Jomon to Yayoi pottery fragments, have been found in this soil layer, suggesting that it was a stage for human activity.

*Some of the terminology that refers to "old sand dunes" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…完新世に形成された海岸砂丘は日本の多くの砂浜海岸に分布し，その形成期は2期に分けられている。おもに縄文前期から後期にかけて(6500～3000年前)形成された旧砂丘と，古墳期以後(1800年前以降)に形成された新砂丘がそれで，この間には，千数百年にわたる植生で砂丘が覆われ，クロスナ層とよばれる厚さ数十cmの土壌層が生成された時期がはさまる。この土壌層からは多くの縄文～弥生土器片など文化遺物が見いだされ，人間活動の舞台になっていたことがうかがえる。…

※「旧砂丘」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報