Geomorphological characteristics of Phong Nha - Ke Bang: rock massif located in the central region with relatively isometric shape with a width of about 30 km and extends over 60 km in sub meridian. Overall Look terrain Phong.Nha - Ke Bang differentiation towards lower from South to North and from West to East. From South to North, limestone has a relatively uniform height, approximately 700 - 900m. From west to east, Ke Bang limestone watershed is the area between the eastern and western Truong Son. Vietnam-Laos border areas including the limestone peaks together with high floor floor 800 - 1000m. Mu Gia Pass in the area exist some high peaks of 1,200 - 1,600m. From West to East Limestone terrain descending to 600 - 700 m and at the edge of the East before moving to the level of 400 - 500m and 200 - 300m.
The geological characteristics of the Phong Nha - Ke Bang: Historical evolution of the geological formations and the world paleontology, evolutionary diverse landforms and terrain associated with the development history of the earth's crust. Each stage of development the crust is shaped by a specific type of structure known as the structural plan. According to research results of the scientists, the Phong Nha - Ke Bang is currently aggregated results of the 5 stages of development in the history crust development in the region:
1. Phase 0rdovic late - Silurian (450-410 million years ago)
2. Devon Period (410-355 million years ago)
3. Stage Carbon - Permian (355-250 million years ago)
4. Phase Mesozoic (250-65 million years ago)
5. Cenozoic Neogene period (from 23.75 to 1.75 million years) and Quaternary (1.75 million year to date)
From the results of that study, the scientists confirmed the Phong Nha - Ke Bang is still present geological events prove the historical development lively crust over 450 million years (from the Ordovician now). Complex tectonics of the Earth's crust is the cause of all causes is so tangled up breaking bottles geological map, which is spiral of evolution to be a vase geological - geomorphological today. Geological structures and lithological composition diversity is a decisive factor of the diversity of terrain - geomorphology and also one of the reasons for decisions hydrographic network, groundwater, climate - natural geography , biological diversity and other environmental landscape bold and mysterious wilderness of nature.
Based on the characteristics of the terrain and level of karts, it may split blocks karst topography of Phong Nha - Ke Bang into 2 categories:
* The average karstic massif with blocks of conical peaks and the high concentration of closed negative terrain.
* Low karstic massif with a top conical shape error, steep slopes and cliffs wide valleys.
From the above presentation may find that limestone to Phong Nha - Ke Bang National Park is one of the largest karst block and not be isolated and in Southeast
Tầng Karts cổ
ASIAN. In it were discovered the caves located in the ink of different heights proved limestone blocks Phong Nha - Ke Bang geomorphological evolutionary history is very long and gone through many cycles. This is also demonstrated by the multi-phase structure of the cave. Currently, the process is going on strong karst in the favorable conditions of lithological, tectonic and climate ... makes the richness of the landscape and the diversity of the natural landscape. So the upcoming detailed studies will tell us in more detail about the meaning of the karst landform in tropical climates hot - humid. This means not only the region but also bring huge international significance to answer the question why in limestone Phong Nha Ke Bang has no cone and tower karst typical in China or North Vietnam and other places.
Although there were some initial results of karst landforms in the area of Phong Nha - Ke Bang National Park, but due to the vast size of the blocks of limestone, karst terrain diversity both on and caves, mostly river cave long and dangerous level of the area should be able to so much unknown location. The results above just performed at the location can be reached relatively easily. It increasingly shows the importance of limestone to Phong Nha - Ke Bang for our understanding of the karst areas in the world. On the other hand, this also causes the level of preservation of natural diversity, including diverse geology and biodiversity is still very good. In particular, the global value of geology, geomorphology and biological diversity as well as the other values are officially recognized, Phong Nha - Ke Bang is eligible to build a geological park ( Geoparks) in Vietnam. The construction of the geological park not only economic development but also tourism associated with sustainable environmental protection. Therefore, the conservation of the karst landscape in this area will bring significant scientific and practical great.