Compare and contrast the factors affecting the coastal features in Tai Tau Chau

Abstract

The factors controlling coastal development can be divided into the factors of land and the factors of sea. Both factors have played an important role in contributing to the erosional coastal landforms in Tai Tau Chau. It is located at the east of Shek O Headland, at the east of Hong Kong Island. The coastal geomorphology is distinctive at this site that various coastal landforms including geo, wavecut platform and sea cliff could be observed. The objective of this study not only is to apply scientific principles in explaining the landforms of Tai Tau Chau, but also to determine the leading factor in controlling the coastal geomorphological development there. From the aspects of land, the geological evolution contributes to the coastal erosional landforms in Shek O Headland. The paleo sea level rise turned this region into a coastal area, bringing a fundamental change in the morphological development. This former inland area becomes a headland that paves the way for further coastal geomorphological development. Moreover, the local geology has contributed to the weathering and erosion processes. The dominant lithology of this region is medium to fine grained biotite granite. The interlocking structure of granite favours the development of joints that further creates lines of weakness at the rock body. Weathering then takes place along the lines of weakness, turning the rock into a softer and weaker state and thus leading to further erosion. Also, the composition of rock is less resistant for biotite is a rather soft mineral compared to others according to the Bowen’s reaction series. The erosion of biotite is intense. Then from the aspect of sea, the wind and wave action is moderate in Shek O. According to the Beaufort wind scale and Douglas sea state, it is only ranked with 3 which represent a calm and moderate condition. However, the prevailing wind is most dominant at east and second most dominant at south. Tai Tau Chau is subject to the wind and wave action from South China Sea without barriers. Therefore, wave erosion is effective especially at the east of Tai Tau Chau—the most jutting part of the Headland at the east of Hong Kong Island.