ultramarinus – beyond the sea

Posts tagged “geology

TALE OF ROCKS, Petra, Jordan

2006.05.21.

The signature quartz sandstone of Petra provides the basis for every single monuments and structures in the ancient city.  The entire city was built by carving into the various sandstones of the region, mainly from the Ordovician (the pale grey and white Disi Sandstone) and Cambrian era (the pale white to red Umm Ishrine Sandstone).  These types of sandstone are common throughout Jordan, but mostly remain underground.  Due to geological activities, these colourful sandstone are being exposed at Petra, Wadi Rum and Dana.  The rhythmic deposition of sand and minerals 540 million years ago have brought us the stunning patterns of the Petra rocks. Likely the carving and excavating properties of Petra’s stone was one of the reasons why the nomadic Nabataeans in the Arabian Desert decided to stay and build their capital city at this location.  The other main reason, perhaps the most crucial one, was the site’s potential to secure water from the surrounding mountains, where winter flash floods would occur after heavy rain.  Today, apart from the majestic Treasury, Monastery and Royal Tombs, most visitors would hardly notice the water channels, underground cisterns, particle settling pools, and mountain reservoirs that once served as the essential infrastructure for the survival of ancient Petra.

rocksApart from its suitability for carving, the rocks of Petra are just simply pleasing to the eye.

06ME37-27Wind and water have played their parts in shaping the rocks in Petra.

06ME37-36But it was the sand deposits and distribution of minerals such as iron and manganese oxides that gave the unique colours to the Petra rocks.

06ME40-22The interesting rock patterns appear in tombs and on building facades.

06ME40-02Many rock patterns appear like abstract paintings.

rock pattern 18 or perhaps Parma ham?

rock pattern 17The colours look brilliant under the right lighting.

rock pattern 16Undulating rock formation.

rock pattern 8The colour ranges from red to orange to brown.

rock pattern 7Some patterns get really complicated.

06ME39-18Another complex pattern.

rock pattern 3Some repetitive rock patterns look like a Futurist painting.

rock pattern 5I spent quite a bit of film (still negative film and positive slides back in 2006) photographing the stone of Petra.

rock pattern 1Not all stone is red and orange.

rock pattern 6Zooming into the rocks.

rock pattern 10Zoom in view.

rock pattern 11Zoom in view.


280 MILLION-YEAR-OLD GEOLOGICAL PARADISE, Ma Shi Chau (馬屎洲), Hong Kong

Ma Shi Chau (馬屎洲), which literally means “horse excrement island”, is a tidal island off a traditional fishing village Sam Mun Tsai (三門仔) at the northeastern New Territories near Tai Po (大埔).  Facing the Tolo Channel opposite from the dam of Plover Cove Reservoir (船灣淡水湖), Ma Shi Chau belongs to the UNESCO Geopark network in Hong Kong.  The remote tidal island is famous for its unique rock formation and outcropped strata dated back to the Permian Period (280 million years ago).

Ma Shi Chau is accessible via Ma Shi Chau Sand Bar (馬屎洲橫水渡).  A short hike on known as Ma Shi Chau Nature Trail will bring visitors to walk along the southeast coast of the island.  Along the coastal areas, unique and colourful rock formations are visible everywhere.  Millions of years ago, Ma Shi Chau was a basin in which surrounding waters continuously to deposit sediments such as sand and gravel.  Over the years as water level changed and so as the kinds of sediments accumulated.   Sedimentary rocks were formed after the process of lithification.  Vaults and folds are also visible on Ma Shi Chau as tectonic movements caused by volcanic activities transformed the rock surface.  Like many parts of Hong Kong, granite is also present at Ma Shi Chau as a result of magma intrusion during the Jurassic Period.  Other than rocks, views of the Pa Sin Leng Mountain (八仙嶺) to the north, and the new town of Ma On Shan to the southeast across the Tolo Harbour (吐露港) are equally impressive.

DSC_3191Sam Mun Tsai (三門仔) is a small fishing village inhabited mainly by former boat people (fishermen families who lived on their boats in typhoon shelter).

DSC_3195From Sam Mun Tsai, a short walk brought me up to a hill dotted with graves.  On the high point, fish farming nets in the waters of Plover Cove.

DSC_3197The trail continued to wind through the ridge of a hill dotted with graves.

DSC_3202The trail then went downhill to the Ma Shi Chau Sand Bar (馬屎洲橫水渡), a natural sand bar that originally would be submerged in water during during high tide.  Over the years, villagers put boulders and sediments on the sand bar, so that it would be exposed above water even during high tide.

DSC_3205Today, the Ma Shi Chau Sand Bar is a convenient venue for a leisure stroll and water activities such as sea kayaking.

DSC_3204The Ma Shi Chau Sand Bar is also the gateway to the Ma Shi Chau Special Area, part of the Hong Kong Geopark.

DSC_3247On Ma Shi Chau Island, there is a short trail called Ma Shi Chau Nature Trail (馬屎洲自然教育徑) bringing visitors to a number of coastal woods and rock beaches.  Giant Golden Orb Weaver, one of the largest kinds of spiders in the world, are quite common in the woods.  Some of these are about the size of a human palm.

DSC_3267Visitors are usually fascinated by the rock formations when arriving at the first open coastal area.

DSC_3295Vaults and folds are visible at Ma Shi Chau due to prehistoric tectonic movements caused by volcanic activities.

DSC_3299Many of the outcropped strata and rock formations are colourful and eye catching.

DSC_3310Details of interesting rock formation on Ma Shi Chau.

DSC_3319Details of interesting rock formation on Ma Shi Chau.

DSC_3331Details of interesting rock formation on Ma Shi Chau.

DSC_3347To the northeast of Ma Shi Chau across the Plover Cove (船灣海), the 2km dam of Plover Cove Reservoir (船灣淡水湖) is only a few hundred metres away.

DSC_3352To the southeast across Tolo Harbour (吐露港), the new residential developments below Ma On Shan (馬鞍山) look like a bunch of toy blocks.

DSC_3359Construction of the new town of Ma On Shan began in 1980s, including private residential developments and public housing estates.

DSC_3363

DSC_3366Fishermen may still test their luck in the Tolo Harbour.

DSC_3371In late afternoon, Pa Sin Leng Mountain (八仙嶺) north of Ma Shi Chau looks gorgeous.

DSC_3374Under the shadow of Pa Sin Leng Mountain (八仙嶺), the tiny island of Yeung Chau and the fish farms in the Plover Cove (船灣海) look like a peaceful picture.


NATURAL vs. MAN-MADE WONDER, High Island Reservoir East Dam (萬宜水庫東壩), Sai Kung (西貢), Hong Kong

Completed in 1978, High Island Reservoir (萬宜水庫) is the largest reservoir in Hong Kong in terms of volume.  Situated at the southeastern end of Sai Kung Peninsula, High Island Reservoir is surrounded by some of the city’s most scenic country parks and pristine beaches.  Designated as an UNESCO geopark, the coastal areas near the East Dam (東壩) of the High Island Reservoir is filled with hexagonal volcanic columns unseen anywhere else in Hong Kong.  140 million years ago, catastrophic volcanic eruption covered much of the area in layers of tuff.  The tuff cooled throughout time and gradually solidified to form rock.  The hexagonal columns were formed from contraction during the cooling.  Today, remnants from the highly active volcanic era become one of the most spectacular natural sights in the city.  Equally impressive at the East Dam are the concrete dolosse blocks at one side of the Dam along the coast.  Each dolos block weights up to 20 tons.  They are used as wave breakers to protect the dam against the rough sea.  To complete the beautiful picture, there are also sea caves and stack islands dotted around the coast, and the azure sky and boundless South China Sea.

01From Sai Kung Town, the taxi ride to the East Dam, the furthest point of High Island Reservoir (萬宜水庫), takes about 45 minutes.

02The spectacular High Island Reservoir East Dam separates the buffer lake of the reservoir and the boundless South China Sea.  Known as Po Pin Chau (破邊洲), the magnificent stack island outside of the East Dam is famous for its tall volcanic columns on one side of its cliff.

03The concrete East Dam structure that separates the two sides of blue water is really photogenic.

04The dolosse blocks pile up on the seaward side of the East Dam, creating a chaotic yet beautiful barrier.  Walking on the dam, we could hear the waves but weren’t be able to find an open view of the sea unless we climbed on the dolosse blocks.

07Once we climbed on the dolosse blocks, we were immediately overwhelmed by the sight of the powerful waves hitting against the coastal volcanic hexagonal columns.

05We climbed down the dam, sat on one of the step and had a quick picnic lunch.

06Looking inland, we could see the inner East Dam that separating the buffer pool with the main reservoir above.  The massive dam structure looked to us as if merged with the adjacent natural landscape.

08Sea caves are common features near the East Dam.

09At the East Dam, natural volcanic hexagonal columns appear side by side with the manmade dolosse blocks.

10To explore a bit of the surrounding coastal landscape, we decided to walk further into the trail heading to Fa Shan (花山) and Pak Lap (白臘).  The trail was not very well defined, but we managed to find our way in the hill of shrubs reaching waist height.

10aOur goal was to at least to have a closer look at the cliff of volcanic columns of the stack island of Po Pin Chau (破邊洲).

11The coastal landscape in the area was truly spectacular.  Some like to explore the area by sea kayaking.

12Passing by the stone beach of Kim Chu Bay (撿豬灣) or Rolling Stone Beach (滾石灘), we saw a few hikers watching the powerful waves.

13Some visitors didn’t mind to get wet and chose to explore by boat.

OLYMPUS DIGITAL CAMERAFinally, we reached the closest lookout overlooking the magnificent Po Pin Chau (破邊洲).

14The stone columns of Po Pin Chau (破邊洲) appeared like a gigantic church organ.

16We then found our way down to the Kim Chu Bay (撿豬灣) or Rolling Stone Beach (滾石灘) to get a even closer look and even touch of the volcanic columns.

OLYMPUS DIGITAL CAMERAAll cliff sides at Kim Chu Bay (撿豬灣) or Rolling Stone Beach (滾石灘) were covered with stone columns.

17After the hike out to Po Pin Chau (破邊洲) and Kim Chu Bay (撿豬灣), it was already late afternoon by the time we returned to the East Dam.

18.JPGInstead of calling a taxi, we decided to walk back out to the main road where we could take a public bus.  The route led us to go along a little over half the perimeter of High Island Reservoir and took about two hours.

19Beyond the haze we could see the Sharp Peak or Nam She Tsim (蚺蛇尖) in a distance, a popular challenge for hikers in Hong Kong.

20Soon the full moon was up over the tranquil water of High Island Reservoir.

21The scenery of High Island Reservoir was serene and calm.

22We enjoyed a few minutes of perfect sunset when we reached the West Dam (西壩).  Beyond the West Dam was Port Shelter Sea (牛尾海) and a series of islands.  The closest island was Tai Tau Chau (大頭洲).

23As the sun gradually set, we picked up our pace of walking.  Known as the Maclehose Trail Section 1, the trail surrounding High Island Reservoir was long but relative flat and easy.  By the time we reached the bus stop at Tai Mong Tsai Road it was almost dark.


TUNG PING CHAU (東平洲), Rocky Paradise in Mirs Bay, Hong Kong

Tung Ping Chau (東平洲) lies at the northeastern-most corner of Hong Kong’s territory. The island is much closer to Mainland China than to Mainland Hong Kong. Long before the island was included in the Hong Kong Global Geopark in 2009, foe decades Tung Ping Chau had been a popular destination for visitors who came to see the island’s unique rock formations and wave cut platforms. Tung Ping Chau was once home to over three thousand inhabitants, and also infamously a . Its population went through a continuous decline in recent decades. Today less than ten islanders called Tung Ping Chau their home. Most people come to the island as tourists on Saturday and Sunday, when the island is served with a daily ferry departing from Ma Liu Shui pier at around 9:00 am. 1The ridge of Pat Sin Leng (八仙嶺) and the dam of Plover Cove Reservoir (船灣淡水湖) lie right in front as we left Ma Liu Shui Pier (馬料水) behind venturing out into Tolo Channel from Tolo Harbour. 2After an hour and fifteen minute of boat ride, we finally arrived at the pier of Tung Ping Chau. Immediately we were captivated by the pristine clear water. OLYMPUS DIGITAL CAMERAUnlike other volcanic islands of Hong Kong, Tung Ping Chau is made of sedimentary rocks. 4Apart than geology, Tung Ping Chau is also renounced for its coastal ecology. In 2001, the sea surrounding the island has been designated as the fourth Marine Park (conservation area) in the city, a marine conservation area. OLYMPUS DIGITAL CAMERASome surviving village homes are used for guesthouses and eateries serving visitors who land on the island every weekend. OLYMPUS DIGITAL CAMERALocal delicacies of Tung Ping Chau include squid with salt and pepper, and sea urchin fried rice. OLYMPUS DIGITAL CAMERADrying cuttlefish. 8Rock formation in Tung Ping Chau is unique down to the smallest details, much owe to erosion caused by the sea waves. 9Crabs of various sizes are common on the island, especially in the tidal pools. 10These tidal pools are completely cut off from the sea during low tide. 11Wandering in the rocky coastal areas on Tung Ping Chau was a surreal experience. 12In many cases, the force of sea waves can be clearly visible from the rocks. 13 Wave-cut platforms. 14 Amazing triangular wave-cut platforms. OLYMPUS DIGITAL CAMERA Some of the rock cuts look so perfect as if they were carved with a knife and ruler. 16 The layering of sedimentary rocks can be clearly seen. 17Clear water, splendid seashells, fine sand, and charming afternoon sun. 18Close-up of a coral head on the beach. 19 As we waited for the returning ferry, we saw a man sat on the rock contemplating the industrial facilities of Mainland China.