Thursday, 26 May 2011

Langkawi Geopark Overview



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Langkawi Geopark is Malaysia's first geopark and is located in the far northwestern corner of peninsular Malaysia. Located in northern State of Kedah, it is unique in the sense that it was formed on 99 islands that together made up the legendary Langkawi Archipelago.

The total land area of Langkawi Geopark is about 478km2.

It is accessible by sea from Kuala Perlis , Kuala Kedah and Penang jetties or by air from Kuala Lumpur, Penang, Singapore and Bangkok.

Langkawi has been dubbed as the birthplace or the fetus land of the region. The various natural landscapes of Langkawi reflects the island's geodiversity and its complex geological history. It has the best-exposed and most complete Palaeozoic sedimentary sequence in Malaysia beginning from Cambrian to the Permian period. Later during the Mesozoic, the islands underwent a major tectonic event that resulted in the emplacement of its numerous granitic igneous bodies.

This incredible power generated by nature from the deep mantle beneath the earth has driven up huge blocks of older rocks and somehow placed them above a very much younger terrain.

In Langkawi geological history, much of its geological development was somewhat linked to what had happened in the old supercontinent Pangea and southern hemispheric Gondwanaland since more than 550 million years ago. It started in the deposition of Machinchang sandstone in a lacustrine environment during much of the Cambrian time, followed by the submergence of the land during Late Cambrian time (--500m.y.) which allowed the invasion of shallow marine fauna into the proto-Langkawi sea. The continuous subsidence of the sea floor resulted in the formation of thick limestone of Setul Formation during the Ordovician. At the end of Ordovician time (--440m.y.), the sea became too deep to eventually stop the limestone deposition temporarily.

Setul limestone continued to develop during Silurian until the Middle Devonian (-370m.y.), followed by the deposition of sandstone and mudstone which sometimes are related to the rafted ice due to the global melting of Gondwana ice cap.

The dropstone bearing black sandstone and mudstone of Singa Formation is succeeded by the limestone of Chuping Formation during the Early Permian (-280m.y.) before the sea was slowly brought up by a complicated tectonic process.

The Chuping limestone is believed to have stopped depositing before the end of Permian (-245m.y.) by this tectonic event that among others brought up a large block of earth crust in the eastern part of Langkawi overlapping the much younger block in the west. The tectonic event ended up with the emplacement of granite beneath the Langkawi crust at the end of Triassic (-220m.y.).

What we have in Langkawi today is a combined result of these various processes and the prolonged weathering process that took place ever since the Langkawi land was brought to the surface around 220 million years ago. As a result, we have a beautiful mountainous range of Machinchang sandstone at the northwestern corner of Langkawi Island, the conical Gunung Raya granite at the center and a rugged karst terrain of Setul Limestone in the eastern part of Langkawi.

In the southwest of Langkawi islands, the Singa formation dominated while the Chu ping Limestone dominates the western part of Dayang Bunting Island. Some of the landscapes are truly outstanding, particularly those of the Machinchang and the karstic limestone in the eastern part of Langkawi.

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