Photos

Daybreak was a good time to see these strange steep limestone mountains arising from the Gulf of Tonkin. As we only spend a night and few hour here, it was a chance to see a most unusual place. It had some James Bond movie surreal feel about it.

Although the name Ha Long Bay is often used to describe the entire area, it refers only to a section of a vast archipelago of thousands of limestone pinnacles stretching nearly a hundred kilometres from Haiphong to the east.

Karst landforms are generally the result of mildly acidic water acting on soluble bedrock such as limestone or dolostone. The carbonic acid that causes these features is formed as rain passes through the atmosphere picking up CO2, which dissolves in the water. Once the rain reaches the ground, it may pass through soil that may provide further CO2 to form a weak carbonic acid solution: H2O + CO2 → H2CO3. Recent studies of sulfates in karst waters suggests sulfuric and hydrosulfuric acids may also play an important role in karst formation.

This mildly acidic water begins to dissolve the surface and any fractures or bedding planes in the limestone bedrock. Over time these fractures enlarge as the bedrock continues to dissolve. Openings in the rock increase in size, and an underground drainage system begins to develop, allowing more water to pass through and accelerating the formation of underground karst features.
Note from Wikipedia.