Internationally rare acidic polygonal volcanic rock columns － High Island

Internationally rare acidic polygonal volcanic rock columns － High Island

Background Information

High Island Reservoir is one of Hong Kong's most popular geological sites, and home to our most spectacular rock wonder. Here, volcanic rock composes neat arrays of giant polygonal joint columns along the shore. Amongst these the hexagonal rock columns are most typical examples. Catching your eyes with striking angular facets, these giants are rare natural prodigies and invaluable geo-tourism resources that draw great interest. Around High Island Reservoir, especially the East Dam, you can observe the most typical hexagonal columnar joints from different angles. There is also a chance to examine the rock composition and structure at close range. Looking down from the East Dam rock cliff, you have a clear view of buckles in the hexagonal columnar joints. Judging by the s-shape section, we know the rock columns buckled under gravity before it could cool down completely and solidify, and thus the scene we see today. With such evidence, it is easy to trace the formation of volcanic extrusive rock. At the observation point for the hexagonal columnar joints, you can also find outcropped basic lamprophyre veins. Lamprophyre is a dark dyke comprising mainly biotite, amphibolite, augite and light minerals like plagioclase and orthoclase. It is usually in vein attitude and wide distribution. Po Pin Chau just off the East Dam is another interesting place to see extraordinary formations. This is where you find giant stacks that emerged when a complete hill was slashed into two by natural forces. It is undoubtedly a fine example amongst similar geo attractions. Geology enthusiasts will certainly cherish the opportunity to see towering rock stacks and fascinating hexagonal joints. Maritime explorers will find Po Pin Chau intriguing and unforgettable. After admiring nature's exquisite works, don't forget to see High Island Reservoir, the impressive man-made wonder. This water storage facility is the biggest in Hong Kong. It is also a water project of key importance. The dramatic East Dam and West Dam are great attractions in their own right. The seafront is protected by concrete dolosse units. Functional as it is visually appealing, this cofferdam attracts many visitors.