In addition to the above described cave and lake systems, Cao Bang is famous for mature and old karst landscape with towers rising on large and flat karst fields on open and extended valleys. This landscape can be observed in many locations in the districts of Trung Khanh, Quang Uyen and Phuc Hoa etc. Other mature karst landforms include the same kind of towers that are interleaved with peak clusters-depressions with enlarged floors and the peaks are only connected with each other near the floor. These landforms can be seen in the districts of Ha Quang and Tra Linh as well as other districts mentioned above. In addition, Cao Bang still has an area of young karst landforms in Luc Khu Plateau (Ha Quang). These landforms are mainly composed of peaks connecting with each other near the top to form karst ranges, or karst landforms interleaving with terrigenous landforms as seen in Nguyen Binh and Thong Nong.
|Ma Phuc Mountain Pass with the winding meanders and karst-tectonic topography (Tra Linh )||U-shape karst valley in Quay Son River (Phong Nam, Trung Khanh)|
|Tower karst topography and karst field (Minh Tam, Nguyen Binh)||Huyen Ru Valley in Ha Lang|
Northwest-southeast tectonic topography (320o) in Nguyen Binh
Ban Gioc Waterfall
Ban Gioc Waterfall is located in Dam Thuy Commune, Trung Khanh District. It is known as the fourth world largest and most beautiful waterfall at an international border, after Iguazu at the border between Brazil and Argentina, Victoria at the border between Zambia and Zimbabwe and Niagara at the border between the United States of America and Canada.
Located on Quay Son River which flows in the northwest-southeast direction, Ban Gioc Waterfall is 200m long and about 35m high, separated into 3 floors. The first floor originates from the river and is 14m high, the second floor falls 10m high and 3rd floor falls 6-10m high. It is composed of primary waterfall and secondary waterfall. The secondary waterfall is situated in Vietnam with the length of 150m and only one floor of 30m high. The primary waterfall is located on the border of Vietnam-China, with the length of 50m. Here, a northeast-southwest-directed fault strikes through thin-to-medium-bedded light grey limestone interleaved with thin brown-grey, green-grey clay shale of the Toc Tat Formation (D3tt), which causes the northwest side to uplift and the southeast side to subside, forming this waterfall. Rock beds of Toc Tat Formation strike 220Ð45o. They were sheared and compressed to form boudinages with the size of up to 1cm. The upper part is limestone of Na Quan Formation (D1-2nq), which is dark grey colored, thin to medium-bedded, striking 320Ð45o, and containing Stromatoporoid Amphipora fossil. Surrounding the waterfall is karst landforms with peak clusters-depressions on planation surface at an altitude of 500m, with thick vegetation cover. Quay Son River Fault valley is in northwest-southeast direction with length of kilometers, containing fault cliffs and karst fields.
|Ban Gioc waterfall (Dam Thuy, Trung Khanh)|