Everyone has Secrets, and this is mine: Sedimentary Rock Landforms at Sentosa

Ah, look! Someone (Marcus) caught me obsessively photographing the rocks:

I have to admit, I went to the Sentosa monitoring trip with a sly ulterior motive - I was dying to take a look at the Sedimentary Rock Cliffs and caves by the coast. I have to say, I was totally blown away.

Alright, before I go any further. Let me first explain what are Sedimentary Rocks. I know most people are probably thinking ROCKS ARE ROCKS, THEY ARE STONES. THE END. but NO! As I have previously harped about, rocks are really records of the Earth's geological history. These historical records can be divided into 3 main groups:

1) Igneous Rocks - Rocks form when volcanic lava cools E.g Granite

2) Sedimentary Rocks - Rocks which are depositions of other eroded materials, and overtime get cemented together E.g Limestone

3) Metamorphic Rocks - Rocks which are formed under intense heat and pressure E.g Marble

So, the cliffs at Sentosa are Sedimentary in nature, namely, they are made of Sandstone:

notice the 'layers' that seem to mark the cliff, this is a characteristic of sedimentary landforms (pls click to enlarge, small pictures dont do these magnificent landforms justice!!!!!!!!!!!)

Also, notice that the cliffs are often bare and un-vegetated. This shows that the erosion processes, driven by the wave actions, are very active. Hence, this part of the island is actually receeding inwards, even now as I type!

A view from the shore:

some of us have the impression that cliffs are like:

(http://www.irishdancingorg.com/)

These cliffs are what I call "geologically mature" cliffs. They go through millions of years of weathering and erosion. and just look at the size of the waves in this above picture, its difficult for Singapore waves to possess THAT much energy as we are surrounded by the Indonesian archipelago. Thus, our cliffs are relatively small, but no less special, as compared to the above.

Who knows, maybe with the tectonic shifts in the region, the cliffs at Sentosa could be like that in 20 million years! (:

anyways, back to my point - here are some observations i made about the cliffs:

(disclaimer: due to the appalling lack of academic literature about Sentosa's Cliffs, these observations are NOT cross referenced)

#1 Can you see that the rocks are kinda tilting in one direction? To help you see, i've drawn some very straight (ahem) arrows on the close up below! This means that the rocks are arranged in such a way that they are Landwards dipping.

This makes this side of the cliff fairly stable - meaning there will hardly be events like Rockfalls or Avalanches. This postulate is supported by the fact that there are no rock debris at the bottom of the cliff.

#2 THERE ARE NATURAL-CAVES IN SINGAPORE:

These caves form at the base of the cliffs, and these are the weakest areas of the sandstone. What do i mean by weakest?? meaning they are the most severely jointed area i.e. they have the most lines of weakness for water to penetrate and weaken the internal structure! such as:

see all the lines and cracks? There's actually a small cave in the making in the pic, try to spot it!

I wanted to duck into the caves for a look, but i was told gigantic spiders lodge in there... *BACKS OUT INSTANTLY* HAHAHAHA. maybe next time (or not).

Lastly, landslides are not uncommon at this side of Sentosa! I love this retaining wall, for some weird reason, it blended right in with the coastal landscape. i almost missed it! Behind it is a bunch of weathered material, clay probably, from the looks of it.

Well, there you have it. Despite the multiple and rather obsessive coastal reclamation (Labrador beach is the ONLY natural stretch in our Southern Coast), these beautiful cliffs remained untouched and often unnoticed. The date of this ONLY bit of graffiti state FEB 1979.

I would hate to think about the day when the government decides that one IR on sentosa is not enough, and this undeveloped bit gets reclaimed as well. Or worst still, this part gets commercialize and becomes part of the STB marketing scheme. so, before all that happens, i hope that my little blog post about this relatively unknown side of Sentosa has opened some of your eyes (:

this is our geological history!

Love, serene!

If you were an ocean, I'd learn to float: Tanah Merah Shore 25/7 (I)

On a bright and early Saturday morning... okay scratch that, on a DARK and REALLY early Saturday morning, 4AM:

(this is the view outside my window)

i crawled up, looking forward, to my first unguided intertidal trip to Tanah Merah shore. according to Kok Sheng, its the best mainland reef in Singapore. i just have to see it for myself

Firstly, some background info on the Tanah Merah area. "Merah" means "Red" in malay, and Tenah Merah was once famous for its red lateritic cliffs.

okay, dont get all worked up over the word "lateritic", it simply means weathered material rich in aluminium and iron. Thus, giving it a reddish tinge. The cliffs, i suppose, are now gone, after massive reclamation occured in the early 1970s. what a pity ):

sometimes development really compromises the natural environment, and unfortunately for singapore, natural landscapes are often placed behind development, due to the Brown Agenda that Singapore adopts. I.e. the government is more concerned with end-of-the-pipe pollution monitoring, instead of conservation.

nevertheless, the reclaimed shore is still brimming with life:

Like these flat heads, a black one and a BW stripped one. i love how they are so placid. unlike some of the other gan-chiong fishes which totally freaked out when we walked a little closer.

we also saw this very very very cute Sweetlip fish. it looks sleepy! im dedicating this picture to the Sweet Leaf karin (:This is one of the very gan-jiong fishes im talking about - a Flat Fish (note different from Flathead). go a little closer to it and it will swim away, rather violently.

And this is a Rabbitfish. its very much alive, i assure you, for it is submerged in the shallow water. however, it attempted to kill itself a couple of times. and we had to nudged it back into the water, and it would violently swim out again. it happened like... 6 times.

'Rabbitfish'- the name makes it sound pretty harmless. however, the spines on the fins contain venomous glands that will sting if touched. its a defensive tool instead of an offensive one, as they are herbivores.

The shore is literally covered with these Creeper Snails, i tried to avoid stepping on them but to no avail. Liana also showed me these very beautiful Dubious Nerite Snails (yes thats their real name DUBIOUS huh) :

they are so incredibly tiny! i thought that they were simply larger grains of sediments. however, if you noticed, each individual snail has different markings on its shell.

This is an orange Moonsnail, so pretty!

This is an Acorn Worm (up). it 'eats' the sediments and extracts the organic materials in the sediments and later passes the rest of the sediments out (down).

This is a Fan Worm when its closed up. And when it is opens, it looks like this:

and another Fan worm of different color, incredible arent they. i used to think that all worms are gross till i saw them.

and there is my favourite, the Peanut Worm:

they are burrowing creatures, and here is an example of a kaypo worm poking out to the surface:

we later saw a whole bunch of different crabs on the shore, most which i cannot identify. like these:

#1

hahaha look at their eyes!

#2

#3

and this is a Moon Crab:

and a very fierce Flower Crab which tried to giap Liana:

its amazing isnt it. that all these could be seen on a reclaimed shore, filled with litter:

(i cant write a proper post without commenting on the rubbish i see) and notice those black dots around the rubbish? they are really the Creeper Snails i mentioned above.

this post is getting a little long hahahaa.

stay tuned for the next one, on the anemones and other critters that we spotted (or at least they spotted HAHAHA). and also the physical geography factors behind it all! This is only the beginning!!! (:

Love, serene!

Special Thanks to: Koksheng for organising this trip, Liana, James and Ivan for company (:

Special Thanks to: Ria for helping me figure out what is wrong with my blogger dashboard!!!

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On a completely unrelated note, ive started a rock collection. my friends who went travelling picked up many many rocks for me along the way. and after every post, i'll talk a little bit about one of them.

so the first candidate:

this is a volcanic rock and it came from Mt Ruapehu in New Zealand. Serchung picked it up for me when he was there for some army training thing (a very convenient valentine's day present).

IT WAS ONCE UNDER THE EARTH'S SURFACE!!!!

okay anyways, Mt Ruapehu is a very active stratovolcano. Its eruptions are explosive in nature, very much UNLIKE those in Hawaii, which eruptions are more subdue. an example of an eruption at Mt Ruapehu:

(source: http://www.craigpottongallery.com/gallery)

the lava (magma = molten rock under the earth's surface, lava = molten rock on the earth's surface), is Andesitic in nature. Andesitic, meaning it has marine mineral influence, as the mt ruapehu is form when the Oceanic crust subducts under a less dense oceanic crust.

This process injects the ocean water into the molten rock (magma) mixture and when the molten mixture comes up to the surface during an eruption, it cools to form the rock i have.

did i lose you guys there? (i think jiayi just fainted). a diagram wld be good here:

(source: USGS)

This process is still taking place today. as one plate continues subducting under the other. it has been taking place over millions and millions of years. HAHA and i have a bit of that history sitting on my desk right now. (:

i love plate tectonics and i promise there will be more of such stuff to come.