Sunday, May 8, 2011

Jeju Volcanic Island and Lava Tubes - South Korea

The Jeju Volcanic Island and Lava Tubes is a World Heritage Site in South Korea. Jejudo is a volcanic island, 130 kilometers from the southern coast of Korea. The largest island and smallest province in Korea, the island has a surface area of 1,846 square kilometers.
A central feature of Jeju is Hallasan, the tallest mountain in South Korea and a dormant volcano, which rises 1,950 meters above sea level. 360 satellite volcanoes are part of the main volcano. Volcanic activity on Jeju began approximately in the Cretaceous and lasted until the early Tertiary period. The last recorded volcanic activity was recorded approximately 800 years ago. The island is covered in volcanic rock and volcanic soil produced by Hallasan. Baengnokdam, the crater and lake in it are located at the peak of Hallasan, was formed over 25,000 years ago.
Jeju is scientifically valuable for its extensive system of lava tubes (also known as lateral volcanoes or in Korean as Oreum). These natural conduits through which magma once flowed are now empty caves that are some of the largest in the world. The caves provide opportunities for scientific research and are also popular tourist destinations. Off the shores of the city of Seogwipo are a vast belt of pillar-shaped rocks that are examples of the natural beauty of Jeju. Shellfish and animal fossils discovered in this area are also very valuable as scientific resources. Beomseom Island and Moonseom Island, also off the city seacoast, are also well preserved and scenic areas. The variety of animal and plant species on Jeju is also an important reason for its value as a natural reserve. Half of all Korean vascular plants grow naturally on the island while another 200 species of plants indigenous to Korea have been transported here. However, half of these species face extinction. The polar plants which came from the south during a glacial period and inhabit the peak of Jeju is one example. Other plants in the subtropical forest and lower regions of the island are also endangered.
Manjanggul is one of the longest lava tubes in the world. Manjang Cave, situated at Donggimnyeong-ri, Gujwa-eup, North Jeju, 30 kilometers east of Jeju City, was designated as Natural Monument No. 98 on March 28, 1970.
The annual temperature inside the cave ranges from 11 to 21, thus facilitating a favorable environment throughout the year. The cave is also academically significant as rare species live in the cave. Created by spewing lava, "the lava turtle", "lava pillar", and "Wing-shaped Wall" look like the work of the gods. It is considered to be a world class tourist attraction. The Geomunoreum lava tube system is the most impressive and significant series of protected lava tube caves in the world and includes a spectacular array of secondary carbonate speleothems (stalactites and other formations). And it overwhelms other lava tubes with its abundance and diversity.
The Geomunoreum Lava Tube System, which is regarded as the finest such cave system in the world, has an outstanding visual impact even for those experienced with such phenomena. It displays the unique spectacle of multi-colored carbonate decorations adorning the roofs and floors, and dark-colored lava walls, partially covered by a mural of carbonate deposits. In addition, lava tube caves are like those in limestone karst in scale, shape and internal decoration, but completely different in origin. Lava tube caves are known from basaltic terrain in most of the world's volcanic regions. The lava tube caves of the Geomunoreum Lava Tube System are, however, regarded as internationally important due to their length, massive volume, intricate passage configuration, well preserved internal lava features, abundant and spectacular secondary carbonate formations, ease of access, and their scientific and educational values.
Another feature making Geomunoreum Lava Tube System globally significant and distinctive is the presence of carbonate deposits and formations. Very small deposits of calcite are common in lava tube caves, and are more significantly developed as speleothems in Duck Creek cave in Utah, USA. However, in abundance, density and diversity they are far less impressive than those of Yongcheongul and Dangcheomuldonggul Lava Tubes in Jeju, and the scale of these decorations within the lava caves of Jeju Island far exceeds any other comparable examples. The nomination is supported by the Commission on Volcanic Caves of the International Union of Speleology - the world's most authoritative scientific body on volcanic caves, which regards Jeju's lava caves as being of the highest international ranking. Yongcheongul Lava Tube has been discovered subsequently and is of equivalent value.

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