Period of the Old Tottori Bay
About 100,00 years ago, the sea was higher than it is today. The Tottori area was a large bay dotted with small and large rock islands, and hilly headlands extended out into the water. Sand continuously flowed into the bay and deposited on the bottom.
Period of the Ancient Sand Dunes
During the ice age, the sea level fell and accumulated sediments emerged as plateaus of thick sand layers. These plateaus became covered by blown sand, eventually forming the Ancient Sand Dunes. Additionally, volcanic ash from Mt. Daisen fell on the dunes where accumulating into distinctive layers.
Period of the Jomon Transgression
After a long period of the Ancient Sand Dunes, the sea level rose again during the Jomon Period and the Tottori Plains became a bay with mud deposits. Towards the end of the transgression, large amounts of sand began depositing.
Tottori Sand Dunes Today
As the Jomon Transgression ended and the sea level dropped, the Recent Sand Dunes accumulated on the Ancient Sand Dunes. The Recent Sand Dunes repositioned themselves often over the years particularly after Japan’s Kofun Period (250 ~ 538 AD). However, because of foresting and river works, sand supply has been recently cutoff, therefore the dunes have stopped growing.