1:45 PM - 3:15 PM
[HCG25-P01] Inland salt production - Distribution, characteristics, origins and historical utilization of salt springs in mountainous areas of the Japanese Archipelago
Keywords:Salt spring, Inland salt production, Fossil sea waterIsotopes, Slab-derived water, Isotopes
In ancient Japan, where transportation and trade networks were not well developed, sea salt was difficult to obtain in inland areas, and the salt water that naturally gushed out in the mountainous areas was an extremely valuable resource. The springs or wells from which the salt water flowed were carefully protected in the region, and the salt water was used for various purposes, such as salt production, cooking, seed selection, removal of astringent taste, drinking, and therapeutic bathing. Such springs and wells (i.e., inland salt springs) were extracted from folk literature (e.g., Hirashima, 1973; Kamei, 1976; Japan Salt Industry Compendium Editorial Committee, 1977; Hiroyama, 1983), as well as from municipal histories and local materials throughout Japan. As a result, the existence of inland salt springs was confirmed at approximately 160 sites throughout Japan, including those where saltwater gushing has now ceased. The depths of the wells were within a few meters. In this article, we introduce the inland salt production methods, the amount of salt produced, and the distribution routes of salt in Onogawa, Yamagata Prefecture, in Aizu-Oshio and Shiozawa, Fukushima Prefecture, in Kashio, Nagano Prefecture, and in Narada, Yamanashi Prefecture, where inland salt production has been conducted using salt springs with high salt concentration since ancient times.
The origin of inland salt springs in Japan is also discussed from a hydrological point of view. Many of the famous salt springs in other countries that have been used for salt production, such as Cheshire in England, Lüneburg and Halle in Germany, Onondaga in the United States, and Sichuan in China, are associated with subsurface rock salt layers, but such rock salt layers are unlikely to exist underground in Japan, because Japan is in a mobile belt. For this reason, the origin of inland salt springs in the past was often attributed to paleo-seawater (fossil seawater) that was incorporated during stratigraphic deposition. However, recent detailed studies based on various isotopes have revealed many salt springs in the forearc region of the Japanese archipelago that are thought to have originated from slab-derived waters (Arima-type hydrothermal waters). In this presentation, the distribution, characteristics, origin, and historical use of these salt springs will be discussed.
The origin of inland salt springs in Japan is also discussed from a hydrological point of view. Many of the famous salt springs in other countries that have been used for salt production, such as Cheshire in England, Lüneburg and Halle in Germany, Onondaga in the United States, and Sichuan in China, are associated with subsurface rock salt layers, but such rock salt layers are unlikely to exist underground in Japan, because Japan is in a mobile belt. For this reason, the origin of inland salt springs in the past was often attributed to paleo-seawater (fossil seawater) that was incorporated during stratigraphic deposition. However, recent detailed studies based on various isotopes have revealed many salt springs in the forearc region of the Japanese archipelago that are thought to have originated from slab-derived waters (Arima-type hydrothermal waters). In this presentation, the distribution, characteristics, origin, and historical use of these salt springs will be discussed.