ENG-2016 — Page 284

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The Environment

The Cleaner Production Partnership Programme encourages and helps Hong Kong-owned factories in Hong Kong and Guangdong to adopt cleaner production technologies and practices. In the light of environmental benefits brought by the programme, the EPD has extended it till March 2020.

Hong Kong and Shenzhen are jointly implementing action programmes to protect the water quality of the adjoining waters, including Deep Bay and Mirs Bay. The two sides completed the second review of the joint programmes for Deep Bay in 2016. The review indicated the programmes were progressing well, with noticeable improvement in the water quality of Deep Bay. The two sides also made recommendations to protect the water environment of Deep Bay. Meanwhile, Hong Kong and Guangdong are actively taking forward a jointly prepared water quality management plan for protecting the water in the Pearl River Estuary, based on their assessment of the estuary's pollution load-carrying capacity.

Physical Characteristics, Flora and Fauna

Topography, Geology and Landforms

Hong Kong's natural terrain is characterised by rugged uplands flanked by steep slopes. The highest point is Tai Mo Shan (957 metres above Principal Datum) in the central New Territories, and the lowest point (66 metres below Principal Datum) is in Lo Chau Mun (the Beaufort Channel) to the north of Po Toi Island. The mountains are predominantly formed of volcanic rocks, whereas the lower hills and low-lying areas are generally underlain by granite or sedimentary rocks. A layer of soft, weathered rock covers the bedrock in most places, slope debris mantles the natural hillsides, and alluvium fills many of the valleys. Offshore, the seabed is covered with marine mud, with sand sheets occurring near the coast and in channels.

The oldest exposed rocks were deposited as river sediments about 400 million years ago. From 350 to 290 million years ago, limestones (now marble) and siltstones, found in western and central New Territories accumulated in a shallow sea. From 170 to 140 million years ago, violent eruptions depositing thick ash layers occurred from several volcanic centres. Volcanism ended with a colossal eruption from the High Island Supervolcano centred in southeastern Hong Kong. Subsequent uplift and erosion have revealed a cross-section from the top of the supervolcano in Sai Kung to its underlying magma chamber in Kowloon and northern Hong Kong Island. Layered rocks seen on the island of Ping Chau are younger sediments, laid down in a lake on the edge of a desert about 50 million years ago.

The northeastern New Territories reveals the most comprehensive stratigraphy of sedimentary rocks in Hong Kong, ranging from Devonian sandstone and conglomerate aged about 400 million years to Paleogene siltstone formed 50 million years ago.

Despite its small size, Hong Kong has a great variety of coastal landforms, including sea cliffs, sea caves, sea arches, geos, tombolos, wave-cut platforms, sea stacks, notches and blowholes.

While most of the hexagonal volcanic rock columns in other regions of the world are composed of basalt lava, those in Sai Kung are made up of silica-rich rhyolitic volcanic rock. Apart from the

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