During the early to middle Jōmon period (approximately 4000 to 2500 BC), sea levels were five to six meters higher than at present, and the ambient temperature was also 2 deg C higher. During this period, the Tōhoku region was inhabited by the
Jōmon people, many of whom lived in coastal settlements. The
middens associated with such settlements contain
bone,
botanical material,
mollusc shells,
sherds,
lithics, and other
artifacts and
ecofacts associated with the now-vanished inhabitants, and these
features, provide a useful source into the
diets and habits of Jōmon society. Most of these middens are found along the
Pacific coast of Japan; however, this side is located on a
fluvial terrace on the left bank of the
Iwaki River, on the southeastern tip of the tongue-shaped plateau with an elevation of 10 to 15 meters jutting out to the Tsugaru Plain, facing the Sea of Japan. Cylindrical pottery found at the site dates it to 4,500-6,000 years ago which corresponds to early to middle Jōmon period. Around this time, the surrounding area was submerged by the expanding brackish water of ancient
Lake Jūsan due to a rise in sea levels. The midden is almost exclusively made of
Yamato-shijimi clams which were harvested from the brackish water; however, other shells, as well as the bones of fish including
carp and
Japanese sea bass and the bones of birds such as geese, ducks and
short-tailed albatrosses have been unearthed. In addition, bone implements made of the bones of large mammals such as whales and dolphins as well as human bones have also been unearthed at the site. During excavation conducted by the Aomori Prefectural Museum from 1990 to 1991, the remains of
pit dwellings, and more than 50 unfinished bracelets made of
Benkeigai (Giycymeris albolineatus) clamshells were discovered, demonstrating that bracelets were made in the settlement. Such bracelets dating from the same period have also been found in
Hokkaidō, and
obsidian from Hokkaidō has been discovered at this site, indicating that production activities and trading across the
Tsugaru Strait occurred during the Jōmon period. The site has been submitted for inscription on the
UNESCO World Heritage List as one of the
Jōmon Archaeological Sites in Hokkaidō, Northern Tōhoku, and other regions There are no public facilities at the site, which has been backfilled and is now located under rice paddies. There is only a billboard with some explanatory text and photographs. ==See also==