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Mid-4. Last Glacial fossil forest in Karuizawa and volcanic geography in Mt. Asama, West Nagano

26 Aug.

Organizer: Hiroo Nasu (

Itinerary: 26 Aug., Meet at 7 am in the Chuo University (Tokyo) –Last Glacial fossil forest site in Karuizawa (West Nagano, Central Japan) – Oni-Oshidashi lava park (Mt. Asama) – Asama Jomon Museum (Miyota) – Chuo University (Finish at about 8 pm)  


Mt. Asama is one of the most active volcanoes with the longest recorded history of documented eruptions in Japan. It is located 130 km northwest from Tokyo in central Honshu, overlooking the resort town of Karuizawa. This field trip will visit a fossil forest outcrop in Karuizawa buried by an eruption of Mt. Asama at 13,000 BP. We will see well preserved plant macrofossils from the Last Glacial coniferous forest (Picea sect. Picea and Pinus pumila) and forest floor mosses (Sphagnum girgensohnii, Pleurozium schreberi, etc.) at the outcrop. We will also visit Oni-Oshidashi (Demon extrusion) Lava Park at the northern foot of Mt. Asama. The lava flow deposits flowed out of Mt. Asama by the eruption in 1783 and covered the villages at the northern foot of Mt. Asama. We will have one hour walk in the Lava Park to see the volcanic geography and the modern sub-alpine vegetation. The last stop is the Asama Jomon Museum that exhibits Japanese prehistoric Jomon culture (semi-sedentary hunter-gatherer society in the Neolithic Japan) affected by the volcanic activity of Mt. Asama. We can see a lot of beautiful Jomon potteries in the museum.

Expense: 12,000JPY includes entrance fees of parks and museum, and a picnic lunch.

Maximum participants: 20

Minimum participants: 4

Additional information:

The trip will take 4 hours in the bus (both ways) and 1 hour of easy walking in Oni-Oshidashi Lava Park. We will cross a small shallow river to reach the outcrop, so long rubber boots and rain gear are recommended.

Mt. Asama

Oni-Oshidashi Lava Park (only Japanese)

Asama Jomon Museum( only Japanese)

Last glacial fossil forest outcrop in Karuizawa

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