Phong Nha-Ke Bang National
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||The karst formation of Phong Nha-Ke Bang National Park has evolved since the
Palaeozoic (some 400 million years ago) and so is the oldest major karst
area in Asia. Subject to massive tectonic changes, the park’s karst landscape
is extremely complex with many geomorphic features of considerable significance.
The vast area, extending to the border of the Lao People’s Democratic Republic, contains spectacular formations including 65 km of caves and underground rivers.
In its justification for inscription UNESCO states that Phong Nha is part of a larger dissected plateau, which also encompasses the Ke Bang and Hin Namno karsts. The limestone is not continuous and demonstrates complex interbedding with shales and sandstones. This, together with the capping of schists and apparent granites has led to a particularly distinctive topography.
The caves demonstrate discrete episodic sequences of events, leaving behind various levels of fossil passages, formerly buried and now uncovered palaeokarst (karst from previous, perhaps very ancient, periods of solution); evidence of major changes in the routes of underground rivers; changes in the solutional regime; deposition and later re-solution of giant speleothems and unusual features such as sub-aerial stromatolites.
The location and form of the caves suggests that they might owe much of their size and morphology to some as yet undetermined implications of the schists and granites which overlay the limestone. On the surface, there is a striking series of landscapes, ranging from deeply dissected ranges and plateaux to an immense polje. There is evidence of at least one period of hydrothermal activity in the evolution of this ancient mature karst system. The plateau is probably one of the finest and most distinctive examples of a complex karst landform in south east Asia.
In summary, Phong Nha displays an impressive amount of evidence of earth’s history. It is a site of very great importance for increasing our understanding of the geologic, geomorphic and geo-chronological history of the region.
Sources and links:
Other World Cultural Heritage Properties in Viet Nam (on this web site). For more information about the individual properties, please refer to the UNESCO-listing, Viet Nam-section.
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Revised 16 sep 2006