Yamaguchi Prefecture
is a Prefectures of Japan, prefecture of Japan located in the Chūgoku region of Honshu. Yamaguchi Prefecture has a population of 1,377,631 (1 February 2018) and has a geographic area of 6,112 Square kilometre, km2 (2,359 Square mile, sq mi). Y ...
,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. It was founded on 1 November 1955 and has an area of 45.02 km².
It includes part of the , a 130 square kilometre area of
karst topography
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...
, as well as over 400
limestone cave
A solutional cave, solution cave, or karst cave is a cave usually formed in the soluble rock limestone. It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum. ...
s. The area is rated a protected landscape (category V) according to the
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
. Like all Quasi-National Parks in Japan, the park is managed by the local prefectural government.
The Akiyoshidai Groundwater System is a
Ramsar Site
A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention,8 ha (O)
*** Permanent 8 ha (P)
*** Seasonal Intermittent < 8 ha(Ts)
**
youth hostel
A hostel is a form of low-cost, short-term shared sociable lodging where guests can rent a bed, usually a bunk bed in a dormitory, with shared use of a lounge and sometimes a kitchen. Rooms can be mixed or single-sex and have private or shared ba ...
and park headquarters building, and is traversed by a scenic roadway and several walking trails. Events include a fireworks festival in July, a “Karst Walk” in November, and an annual burning off of dry grasses in February called “Yamayaki”.
Geology
The plateau consists of uplifted reef
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
s of
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
age, which were thickened by overfolding during the Akiyoshidai orogenic movement. Subsequent erosion has created an undulating
karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...
landscape dimpled with many dolines and countless limestone pinnacles up to two meters in height. Beneath the surface lie hundreds of caves, a few of them quite significant geologically. Numerous fossils of
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
age have been found in these caves, including those of the Japanese
rhinoceros
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...
,
Stegodon
''Stegodon'' ("roofed tooth" from the Ancient Greek words , , 'to cover', + , , 'tooth' because of the distinctive ridges on the animal's molars) is an extinct genus of proboscidean, related to elephants. It was originally assigned to the famil ...
t elephant,
Naumann elephant
''Palaeoloxodon naumanni'', occasionally called Naumann's elephant, is an extinct species belonging to the genus '' Palaeoloxodon'' found in the Japanese archipelago during the Middle to Late Pleistocene around 430,000 to 24,000 years ago. It is n ...
, Young
tiger
The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...
, and many other animals from the last interglacial period.
The area around Akiyoshidai was heavily forested about 500,000 years ago. In the
Jōmon period
The is the time in Japanese history, traditionally dated between 6,000–300 BCE, during which Japan was inhabited by a diverse hunter-gatherer and early agriculturalist population united through a common Jōmon culture, which reached a c ...
, with the general area serving as a hunting ground and the bottoms of
sinkhole
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...
s as vegetable fields. Numerous
Paleolithic
The Paleolithic or Palaeolithic (), also called the Old Stone Age (from Greek: παλαιός ''palaios'', "old" and λίθος ''lithos'', "stone"), is a period in human prehistory that is distinguished by the original development of stone too ...
artifacts have been recovered. As farming started in Japan the local people eventually entirely replaced the forested landscape with
Japanese pampas grass
''Miscanthus sinensis'', the eulalia or Chinese silver grass, is a species of flowering plant in the grass family Poaceae, native to eastern Asia throughout most of China, Japan, Taiwan and Korea.
Description
It is an herbaceous perennial g ...
for feeding their animals and thatching houses. Repeated cycles of burning the grass have kept trees from growing back since.
Akiyoshidō
Towards the southern end of Akiyoshidai is the Akiyoshidō
cave
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...
, named by
Emperor Hirohito
Emperor , commonly known in English-speaking countries by his personal name , was the 124th emperor of Japan, ruling from 25 December 1926 until his death in 1989. Hirohito and his wife, Empress Kōjun, had two sons and five daughters; he was ...
on May 30, 1926, when he was still
crown prince
A crown prince or hereditary prince is the heir apparent to the throne in a royal or imperial monarchy. The female form of the title is crown princess, which may refer either to an heiress apparent or, especially in earlier times, to the wif ...
. This spacious cave is up to 100 meters wide and has 8.79 kilometers of passages, making it one of the longest in Japan after Akkadō cave, and one of the longest in Asia. At the present time an about one-kilometer-long section of the cave is open to the public as a sightseeing course, with a walkway and bridge system, entering at the cave's lowest point and exiting via an artificial elevator. This portion of the cave is also well decorated with a variety of large and colorful
speleothem
A speleothem (; ) is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on ...
s.
Gallery
Image:Gold Column at Akiyoshi Cave.jpg, Stalactite called "Gold Column"
Image:Akiyoshidai_001.jpg, View of Karst landscape
Image:Akiyoshidai-Syuhodou.jpg, Inside Akiyoshidō caves
Image:Karst topography at Akiyoshidai.jpg, View of Karst topography
See also
*
List of national parks of Japan
and in Japan are places of scenic beauty designated for protection and sustainable usage by the Minister of the Environment under the of 1957. National Parks are designated and in principle managed by the Ministry of the Environment. Quasi-Nat ...
*
Ramsar sites in Japan
The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of wetlands. Adopted in 1971, it entered into force in 1975 and as of April 2022 had ...
References
*Southerland, Mary and Britton, Dorothy. ''The National Parks of Japan''. Kodansha International (1995).
*Stanley, George D. ''The History and Sedimentology of Ancient Reef Systems.'' Springer (2001).
*Okada, Hakuyu. ''The Evolution of Classic Sedimentology''. Dunedin Academic Press (2005)
*Waltham, Tony. ''Great Caves of the World''. Firefly Books (2001).