Phong Nha – Ke Bang National Park
Phong Nha – Ke Bang National Park is in Quang Binh Province – Central Vietnam. With an area of about 200,000 ha, Phong Nha – Ke Bang is located in the districts of Quang Ninh, Bo Trach, Tuyen Hoa and Minh Hoa, 50km northwest of Dong Hoi city.
In addition to the historical value of geology, topography, geomorphology, Phong Nha – Ke Bang National Park is also endowed with mysterious and majestic landscapes. This place hides many mysteries of nature.
Phong Nha – Ke Bang National Park is likened to a huge geological museum of global significance because this place has a complex geographical structure, gathering many different rocks such as sandstone, quartz, schist, silicic limestone, macaroni, granodiorite, diorite, aplite, pegmatite, etc. This place also contains complex geological development history. Experiencing important tectonic phases and fault movements, rock formation, and folds have created overlapping mountains and subsidence of sedimentary basins. The above changes have also contributed to the diversity of geology, topography and geomorphology.
Phong Nha – Ke Bang limestone region has global characteristics in many stages of development from the Late Ordovic – Silur (463.9 – 430 million years ago) to the Quaternary (1.75 million years ago). A unique feature here is the underground river system and caves in the limestone mountain.
The non-limestone geomorphologic region has a common feature of low mountains with vegetation cover on the surface. Erosion creates terraces along river valleys like Son River, Chay River or on the banks of limestone mountains in the central region. The transitional terrain is different types of limestone mountains.
Phong Nha – Ke Bang is located in an area with relatively high average annual rainfall but the water here has absorbed and flowed underground in the limestone mountains. Over tens of millions of years, there are countless caves created in this area. In Phong Nha – Ke Bang National Park, there are about 300 large and small caves. They are divided into three main systems including Phong Nha cave system, Vom cave system and Ruc Mon cave system.