High Island is one of the major parts of the Hong Kong Global Geopark of China, a beautiful area characterised by the hexagonal rock columns.
This tour I organised for the local geocaching community, and with a total of about fourteen people, some new to geocaching and others just in it for the views, we set off from the East Dam on this Sunday morning.
East Dam has one of the best exposures of the hexagonal columns – and at the foot of them of course a geocache is hidden. This exposure is largely thanks to excavation work done for the construction of High Island Reservoir in the 1970s.
Now it is a key part of the geopark, and information displays at this site explain how these columns were formed out of the hot volcanic ash, and showcase later changes to the rocks such as a fault breccia, bends and an intruded dyke.
At the end of the coffer dam it is a bit of as scramble around a fence to get onto the trail. Trails here are rough and mostly unmaintained, often steep and covered in loose rocks.
It is not easy or fast going, care has to be taken when negotiating this kind of terrain.
Our first destination is Po Pin Chau, a sea stack. Original a headland connected to the main island, waves pounded on the rocks creating a sea cave at a weak spot. Over time this sea cave became bigger, until it broke through on the other side, creating a sea arch. Finally when the sea arch became too big, the roof collapsed creating this small island with a narrow sea passage between it and the mainland.
From Po Pin Chau we headed towards Fa Shan, lit. Flower Mountain. Not many flowers in this season. Terrain here is not too bad, due to the dry and rocky land not much is growing here which helps in keeping the trails open.
We continued our exploration by heading out onto the next headland, east of Pak Lap Tsai bay. The terrain here quickly got rougher, loose rocks everywhere and barely any soil to hold it all together. This headland has a few sea caves as well, however there was no way for us to climb down to the shore to have a look at them.
However we did get a look, from afar, at the Mok Min Cave, a sea arch, showing as a hole in the mountain. Over time – in the tune of millions of years – this arch will widen thanks to the continuous wave action, until its roof collapses and another sea stack is formed.
From here it was a longer walk to get to our next cache, which was placed right above Mok Min cave.
Continuing over the slopes of Fa Shan we finally made it to Pak Lap Tsai beach, a pebble beach. The last bit of the trail went almost vertical down, however with the many protruding rocks it was not too hard to negotiate.
Many different rocks can be found on this beach, all perfectly rounded due to being transported around the sea before ending up on this beach. Large chunks of coral can also be found here, again perfectly rounded, light in weight and with the structure of the coral skeleton visible at the surface.
From the other side of the beach it was up the hill again. At times the trails got easier, mostly because there was some level ground, where we could make some good progress.
Finally we arrived at the end of this headland, and after logging the cache it was time to try and find the sea arch. We had met some hikers on the way that showed us the photos, so we knew the arch can be reached. It was just a matter of how to get there, and whether the tide was not too high.
We managed to get quite close to the arch, approaching it down the north-eastern slope. A really tricky climb, but we finally got a closer look of this interesting feature. Unfortunately the tide was way too high to have any chance of approaching the tunnel even closer – this is as close as I could get.
This is also the ocean-ward side, meaning the wave action is mainly from this side. The other side of the headland has gentler slopes as the waves are far less powerful, both due to the prevailing wind directions and due to the lack of space for waves to build up.
During my subsequent visit to this arch I tried the other side, a much easier approach and the arch can actually be accessed that way.
By then it was already well into the afternoon, and upon arrival at Pak Lap village we crashed down at the local bar for a simple lunch. We had really walked only about 7 km but it had taken five hours to get that far! Everyone was hungry, making the food taste extra good.
The final destination of our hike was now within reach, it was less than half an hour walk to Sha Kiu. The footpath between these two villages is concreted, making it even easier.
Sha Kiu is a small fishing community, currently home to a large number of fish farms. There is also a restaurant which opens on weekends only, serving tourists.
Having found our final cache we asked the restaurant to call a boat for us for the final leg of our journey: via the Ung Kong Group back to Sai Kung, and we sat down at the restaurant for a drink while waiting for our transport to arrive.
It was a small and really fast boat, making the trip extra exciting. The winds were light, though as soon as we got a bit further out we got on the long ocean waves, and the skipper had to slow down to limit the spray.
Beautiful seascapes on the way. All these shores are full of sea caves, inlets and other features caused by prolonged wave erosion.
First up: the sea arch at Basalt Island.
The name Basalt Island is a misnomer, as the rock here is not basalt, it’s tuff. The island was named Basalt Island by the British, as they saw the rock columns and assumed this is basalt, a material well known for forming such columns.
The arch here appears slanted, this is because the rock columns here are at an angle. The shape of the arch follows the joints in the columns.
Next up: the sea arch at nearby Bluff Island. This remarkable arch is incredibly straight: straight walls, almost flat roof. This is probably the result of the columnar structure of the rock, as soon as a rock is undermined the whole column breaks off, leaving a perfectly straight wall.
Upon careful examination it can be seen that the rocks at both these arches look slightly different from the surrounding rocks; this is no surprise as a sea arch will always form where there is a weakness in the rocks.
From here it was a straight line back towards Sai Kung, sailing by Jin Island and Sharp Island. The latter also has quite some interesting landforms at it’s southern end, which we did not explore this time.
It was nearly 18:00 when we finally arrived back in Sai Kung. Our 8 km hike took us over 7 hours – including breaks, lunch and geocaching. And spending a long time at the various viewpoints admiring the surroundings. Very tiring, but overall it was a great day.