1. Our enquiry issue

The enquiry issue of our group is the difference between the coastal landforms in Cheung Chau and Ping Chau. We are interested in the comparison of the coastal landforms in the Cheung Chau and Ping Chau. As we know that, the physical features in Ping Chau are more famous than Cheung Chau. Now we are going to present the coastal landforms in both Cheung Chau and Ping Chau.. So our focusing question is

“Why are the wave-cut platforms, sea cliff and stacks more famous in Ping Chau than Cheung Chau?”.

2. The background information

As we know Cheung Chau is a tomobolo. It is located between the Lantau island and Lamma island, which is a small island 10 km southwest of Hong Kong Island. There are one wave-cut platform, one sea cliff and one stack, located in the Nam Tan Wan in Cheung Chau.(refer to attactment 1).

For Ping Chau, it lies in Mirs Bay, in northeastern Hong Kong. This island is named for the most popular of Hong Kong’s four best-known natural sights. This island is made of sedimentary rocks. Its name means “Flat Island”. There are many coastal landforms, such as wave-cut platforms, sea cliffs and stacks. In addiction, there are also sea caves and sandy beaches. The wave-cut platforms is located in the Kang Lau Shek(更樓石), and there are two sea stacks measuring 7-8m standing on the wave-cut platform. The sea cliffs are at Lan Kwo Shui (難過水), which are connected with the formation of a wave-cut platform. For sea stacks, they are located in the Kang Lau Shek and Chum Kang Chau(斬頸洲. For the map of Ping Chau and the location of the coastal landforms,  see attachment 2.

3. The wave-cut platform

(i) Wave-cut platform in Cheung Chau(refer to attachment 3)
Cheung Chau’s wave-cut platform is located in the Nam Tan Wan. It is formed by the wave erosion in the water moving from the south-east. “A wave cut platform can be found below the human head rock. A line of weakness is usually found at headlands. Wave energy is concentrated at the line of weakness (joints, fault lines, etc.) The cracks widen as wave erosion advances. A notch will be formed. After prolonged wave erosion the notch deepens. The overhanging walls collapse to form sea cliff. With further erosion the wall retreats towards the land and the area under the cliff widens. Thus a wave cut platform is formed. The platform is exposed.”  Sources:(http://www.qc.edu.hk/it-school/homepage/geog/cheung%20chau/web/phy.htm)


(ii) Wave-cut platform in Ping Chau(refer to attachment 4)


The wave-cut platform in Ping Chau is located in the Kang Lau Shek to Lan Kwo Shui. They are at the southeastern tip of Ping Chau. And Lan Kwo Shui is in the west of Kang Lau Shek. The wave-cut platforms are measured about a hundred meters in length, the largest and the most famous in Hong Kong. It extends more than 33m inwards from the sea. As the sea is rough in the south and south west, so the wave erosion is active in the Kang Lau Shek and Lan Kwo Shui. Erosional landforms are formed there – wave-cut platform.(refer to attachment 3)

4. The sea cliffs

(i) Sea cliff in Cheung Chau(refer to attachment 5)

The sea cliff is connected with the wave-cut platform in Nam Tan Wan. Wave energy is concentrated at the line of weakness (joints, fault lines, etc.) The cracks widen as wave erosion. The overhanging walls collapse to form sea cliff.


(ii) Sea cliffs in Ping Chau(refer to attachment 6)

The sea cliffs in Ping Chau are in Lan Kwo Shui. There is an almost vertical cliff that plunges down to meet the sea. This region is the highest point along the west of the Ping Chau. The waves keep erodes the coast, many precipitous(陡峭) cliffs. Some sea cliffs are still forming and some are receding because the platform is widening. But some have stopped the forming process as the cutting power is lost.

5. The stacks

(i) Stack in Cheung Chau(refer to attachment 7)

The stack in Cheung Chau is called ' Man Tou Rock' because its shape is oval and the surface is smooth. “It is also very small in size, which does not seem like joined to the headland originally. This means that the stack has undergone prolonged weathering and erosion. Destructive wave causes solution and attrition, which tends to round of the angular boundaries of rock. Temperature changes also cause block disintegration, causes the rock to reduce in size.” Sources:(http://www.qc.edu.hk/it-school/homepage/geog/cheung%20chau/web/phy.htm)

(ii) Stacks in Ping Chau(refer to attachment 8)

There are two famous stacks at Kang Lau Shek, about 6m tall each. The one stack at Chum Kang Chau was cut off from the mainland, but according to the information we found, it has now been joined to the land by deposition.

6.Conclusion

With the above information, we can prove that the coastal landforms in Ping Chau are more famous. Ping Chau has a very good sight of physical features, since the wind direction of Hong Kong is north-east to south-east, so the biggest wave-cut platform we can found in the south-east of Ping Chau. Furthermore, bigger wave erosion lends to bigger wave-cut platform and higher erosion of cliffs, the cliffs are really high in Ping Chau, which makes the highest point in Ping Chau. Most interesting thing we found is the stack in Chum Kang Chau in Ping Chau, originally, it was separated, but lately, it had been joined to the land again because of deposition...also the unique sedimentary rocks (shales) i.e. the geology. . And Cheung Chau has a higher value of its tourism, but Ping Chau has a higher value of its geographic knowledge.

Attachment 1

Sources: reference 6

Attachment 2

sources: reference 8

Attachment 3

Wave-cut platform in Cheung Chau

Attachment 4

Wave-cut platform in Ping Chau

Sources: reference 4

Attachment 5

Sea cliff in Cheung Chau

Sources: reference 2

Attachment 6

Sea cliffs in Ping Chau

Sources: reference 4

Attachment 7

Stack in Cheung Chau

resource: reference 2

Attachment 8

Stack in Ping Chau

Sources: reference 7

Attachment 9-Reference

Websites:

1. Cheung Chau HK 長洲HK South China Sea island in Hong Kong, 2010
http://www.cheungchauhk.com/



2. Physical Geography Of Cheung Chau,2003
http://www.qc.edu.hk/it-school/homepage/geog/cheung%20chau/web/phy.htm



3. Weathering & Erosion - Introduction to Geomorphological Processes - Hong Kong Geology,2009
http://hkss.cedd.gov.hk/hkss/eng/education/GS/eng/hkg/chapter4.htm


4. Tung Ping Chau Physical Features,2008
http://www.cis.edu.hk/sec/ss/TPC_HERITAGE/physical/index.html



5. Physical Geography of Ping Chau, 2008
http://www.cis.edu.hk/sec/ss/TPC_HERITAGE/physical/Physicalgeo.doc


6.中原地圖, 2010
http://www.centamap.com/gc/home.aspx


Books:

7. 魏遠娥(2002)/ 東平洲全方位生態探索, P.21-29, 香港郊野公園之友會,天地圖書



8. Hong Kong. Agriculture, Fisheries and Conservation Department(2005), An island alone : Hong Kong's Tung Ping Chau, Hong Kong : Friends of the Country Parks ; Cosmos Books