Niah Quarry: Look at the size of the Hill compared with the lorry
Pinnacles(Don't have to climb Gunung Api to see this. haha! I can even see it cut into half!)
At the quarry, we were trained to open our eyes as wide as possible, using the microscope to look through every rock, looking for fossils and minerals. Hmm.. since I didn't really pay attention to what the instructor said under the burning, hot sun, my memory fails to enlighten me even though I am squeezing my brain juices dry.
Seashells embedded in rocks. Dark Grey:Mud, Light grey: FossilsSo, when we did look hard enough, and train our eyes to be really sharp, we spotted several rocks with corals inside it! The more we scanned through the area, the more surprise we got! We spotted several rocks with calcite or pyrite minerals growing inside the rocks! They were white, translucent and very very light! Geez!
Calcite Minerals Formed in Carbonate RocksGuess what? When we poured Hydrochloric acid on this carbonate rocks, they fizzled like the foams on the sea.
Fizzling Carbonate Rocks (Reacts with Hycrochloric Acid)
Types of Carbonate Rocks (According to increasing Mud composition, from right)Whackedstone (More than 8% Granules), Grainstone, Mudstone (Less than 8% Granules)
Walking Under the Bright Hot SunThough we had to walk under high heat on that bright, sunny day, we learnt a lot. We even got to climb to the viewing point at the hill with the Telekom Tower, and look at the Reef from afar. If all of this Niah were under water, it would have been equivalent to Australia's Great Barrier Reef. ( I guess).
Look at all these Carbonate Reefs. The whole dark green stretch of Carbonate Rocks which used to house Corals and abundant marine life.What a long and big platform! Amazing, isn't it?
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Facts about Carbonate Rocks
Calcium carbonate rocks are formed from corals and marine life, animals and plants under the sea. They are plant matter, need lots of light to survive. Corals are only able to survive in warm weather. That is why there are lots of carbonate reefs in the Middle East. However, there is an exception. In some parts of the world, white corals do exist in deep marine environment. They are formed from algae. Because there is no light, the plants are unable to conduct photosyntesis, so, its white instead of being multi-coloured.
Upon first look, one might think that the whole stretch of carbonate reef was formed at the same time. However, that is a misconception. In actual fact, when we scrutinize this outcrop, we will notice the sigmoidal patterns on the rocks (Figure below). This tells us that the reefs were formed at different periods of time.
Do you know how caves are formed? Carbonate rocks are very brittle structures which contain lots of calcium. When subject to forces, they break and fracture easily, forming good reservoirs for hydrocarbon. So, when a pore or a fracture is present in the rock, it will form a natural flow path. Water from the ocean will flow through it, bringing along sand and finer materials which will erode and 'knocks' against the walls of the hole. After a long time and a repetition of the above process, the hole gets bigger and bigger, until finally, a horizontal hole is formed from the horizontal flow.
When the earth moves, and the plate on which the carbonate reef is seated upon is compressed, our reefs will rise higher and higher, until it is elevated above sea level. Soon, just a small stream of river will flow through that hole. As the plate gets lifted up higher, the cave is elevated as well. That horizontal hole is what we call "caves".
When we travel along Ipoh roads and the Batu Caves, we will notice that there are several caves which are located at different heights on the same limestone hill. What I never notice is that these caves are often 'seated' one upon the other. It looks like a series of caves. How can that be?
Well, when the first cave is formed, the carbonate rock is uplifted as well. After some time, more and more caves will be formed and we have then a very complicated network of cave system. One thing we must remember though. The oldest caves are at the top of the hill and the youngest caves are at the bottom of the hill. This is probably because the water near the surface is more turbulent than the current at the seabed. So, the chances of being 'roughen up' is higher at the top.
And that, is the story of the formation of Niah and Mulu Caves and limestone hills.
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Upon first look, one might think that the whole stretch of carbonate reef was formed at the same time. However, that is a misconception. In actual fact, when we scrutinize this outcrop, we will notice the sigmoidal patterns on the rocks (Figure below). This tells us that the reefs were formed at different periods of time.
Do you know how caves are formed? Carbonate rocks are very brittle structures which contain lots of calcium. When subject to forces, they break and fracture easily, forming good reservoirs for hydrocarbon. So, when a pore or a fracture is present in the rock, it will form a natural flow path. Water from the ocean will flow through it, bringing along sand and finer materials which will erode and 'knocks' against the walls of the hole. After a long time and a repetition of the above process, the hole gets bigger and bigger, until finally, a horizontal hole is formed from the horizontal flow.
When the earth moves, and the plate on which the carbonate reef is seated upon is compressed, our reefs will rise higher and higher, until it is elevated above sea level. Soon, just a small stream of river will flow through that hole. As the plate gets lifted up higher, the cave is elevated as well. That horizontal hole is what we call "caves".
When we travel along Ipoh roads and the Batu Caves, we will notice that there are several caves which are located at different heights on the same limestone hill. What I never notice is that these caves are often 'seated' one upon the other. It looks like a series of caves. How can that be?
Well, when the first cave is formed, the carbonate rock is uplifted as well. After some time, more and more caves will be formed and we have then a very complicated network of cave system. One thing we must remember though. The oldest caves are at the top of the hill and the youngest caves are at the bottom of the hill. This is probably because the water near the surface is more turbulent than the current at the seabed. So, the chances of being 'roughen up' is higher at the top.
And that, is the story of the formation of Niah and Mulu Caves and limestone hills.
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