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Not many aware of prehistoric stone in Langkawi


LANGKAWI: A granite dropstone, said to be dating back a billion years, exists in a mudstone at Pulau Tepor, southwest of Langkawi. 

Two British geologists, who used a radio-metric system to determine its age, discovered the stone 30 years ago. 

GEOLOGICAL TREASURE: The one-billion-year-old granite dropstone is lodged in the mudstone andsandstone formation in Langkawi.

Universiti Kebangsaan Malaysia’s Institute for Environment and Development (Lestari) deputy director, Prof Mohd Shafeea Leman, said it was one of the geological treasures found here. 

Not many people are aware of the stone’s existence, he told The Star, adding that it was the oldest dropstone found in this region.  

“It may appear dull but it has a very interesting story behind it,” the professor said. 

Explaining dropstones, he said they were pebbles or blocks of rock brought by glaciers millions of years ago and dropped on the seafloor.  

The presence of the dropstone implies that the Langkawi islands were once joined with other continents and sub-continents such as Australia, India, Africa and Antartica, in a super-continent called Gondwanaand during the late carboniferous to early Permian time (about 280-300 million years ago). 

“This particular stone (measuring 25cm by 16cm) once drifted along in a glacier before it was dropped in Langkawi, which was submerged in water a long, long time ago.  

“How did the glaciers come near Langkawi? 

“Langkawi, parts of Sumatra, Thailand, Burma and a small part of southern China, were part of the Gondwana super-continent that included Antarctica, South America, Africa, Madagascar, Australia-New Guinea, New Zealand, Arabia and India,” said Prof Mohd Shafeea, adding that Langkawi later drifted away to its present position. 

For more information on the Langkawi dropstone, visit http://pkukmweb.ukm.my/~geologi/abstrak_semak.htm 

Another geological treasure in Langkawi comes in the form of an ancient seabed. 

“We can now walk on this ancient seabed in Pulau Ular. 

“The seabed was exposed about 5,000 years ago when the sea level subsided in this part of the region,” he said. 

   

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