Assalamualaikum! Angpa semua sihat ka? Mai cheq nak habaq pasai fieldwork aritu. :D
Inspired by fieldwork blogposts like Hdin's and Kak Mahirah's blog - I'm gonna do my best to summarize all 7 days in this post as reference for me and my classmates (untuk exam final nanti) and for my adik-adik who will embark on this trip too one day when they get into their second year. (:
Do take note that this is not going to be a complete guide. Cerita lokaliti sikit-sikit je. Tak mampu nak cerita in full. Nak yang complete kena baca buku and turun field.
Fair warning - this is going to be in ROJAK. So, language-lovers, forgive me this time around.
Here it goes! :D
KEDAH AND PERLIS
DAY 1
Locality #1: Bandar Aman Jaya
Mahang Formation
Age: Ordovician - Early Devonian
Here you would visit two road cut outcrops.
Outcrop 1(A) focuses on the ARGILITE FACIES of this formation.
See those tiny petak-petak embedded in the outcrop wall? There used to be some cubic mineral in there. (Hint: Fool's gold.)
Outcrop 1(B) on the other hand focuses on the SILICEOUS FACIES of this formation.
*This formation was deposited in an euxinic environment (deep marine, lacking in oxygen) This is supported by the finding of black mudstone rich with oxidized (?) pyrite and iron pans in Outcrop 1A and chert (made from the siliceous remains of nektons sunken to the bottom of the ocean) and siliceous mud (also from siliceous material yang tenggelam) in Outcrop 1B.
[I have this noted somewhere in my field notes, but belum dapat balik. So this is drafted from memory. Kalau salah kasi betulkan cepat. Thanks!]
DAY 2
Locality #2: Seri Perigi
Jerai Formation
Age: Cambrian
Things to do here:
1) Identify the type of rocks that make up the Jerai Formation
[Buku panduan says... "schist, hornfels and metaquartzite"]
2) Identify the minerals that make up the rocks
3) Tentukan batuan mana paling tua, batuan mana paling muda.
Here you will start to link two formations together. In the picture above, Prof. Basir is showing us the relationship between the Mahang Formation (from Day 1) and Jerai Formation (Day 2).
In addition to a number of pegmatites in the form of dykes and sills, there are a few sedimentary structures that need to be observed and sketched.
Sedimentary Structure #1 : Large scale cross bedding / Mega cross bedding.
It's up there. Way up there. Kat tempat yang nampak macam lapis-lapis tu. Nampak tak? *points*
Sedimentary Structure #2 : Ripple marks
Sedimentary Structure #3 : Planar cross bedding
Struktur-struktur ni boleh digunakan untuk menentukan arah aliran arus kuno. How? Guna stereonet. (:
'Batuan kat sini metamorphic - kenapa pulak ada sedimentary structures? Bukan batuan sedimen je ke?'
Betul la struktur sedimen tu ada dalam batuan sedimen je. Sedimen yang ada struktur sedimen tu termetamorf selepas sedimen tu dah mengeras menjadi batu. So, sedimen + ripple marks --- jadi batu --- termetamorf. Faham kah?
Locality #3: Sg. Batu Pahat, Lembah Bujang
Things to do here:
1) Observe the pegmatite dykes
2) Identify and differentiate : chilled zone and baked margin
3) Identify the rocks
4) Identify the minerals.
Yes, this is a historical site, so try not to hit the rocks. (:
Dr. WZWY used to say "Nak tengok gajah jangan tengok dekat-dekat. Tengok dari jauh. Kalau tengok dari dekat mungkin kita kata gajah nampak macam belalainya, mungkin macam kakinya. Tengok dari jauh barulah nampak rupa sebenar gajah tersebut." Or something like that. Hahaa
Kesimpulan : Tengok dari jauh dulu. Jangan terjun je tengok outcrop terus. And oh, don't forget to sketch!
Some of the coarse mineral grains found here. The black ones are large bits of tourmaline! Don't confuse the coarse minerals for xenoliths. (Because the xenoliths here are black too.)
Xeno - foreign, Lithos - rock = foreign rock. The keyword here is ROCK. So if there is a fragment of rock that does not belong to the granitoid body, it is most probably a xenolith. Batuan asing la kiranya.
Just a bit of history kejap : Why is this placed called Sungai Batu Pahat anyway?
(Hint : Tengok gambar di atas.)
Yup, the granite rocks here were used to make the famous candi (temples) here. Batu tu kena pahat in order nak buat bongkah-bongkah yang membina candi tu. Hence the name, Sungai Batu Pahat. (:
Now you know!
*
Baked zone: Dalam batuan asal (in the surrounding rock), butiran mineral kasar-kasar. Direjah igneus, panas, terpanggang, slow-cooling --- butiran kasar.
Chilled margin: Dalam batuan igneus (along the margin of the intrusion), butiran mineral halus-halus. Igneus panas, batuan asal relatively sejuk, fast-cooling --- butiran halus.
Locality #4: Singkir Laut
Quarternery shell deposits
Age: Quarternery; Holocene (~7000 years ago)
Things to do here:
1) Identify fossils and sketch!
2) Memorize the names. Confirm keluar kuiz. :D
Left to right: Anadara granosa (macam kerang kita makan) and Geloinia ceylonica (yang patah sikit tu.)
This one is called Saccostrea cuccullata a.k.a. Tiram Batu.
Ni pulak fosil lokan. Gigi heterodont. Memang jelas. Ingat lagi tak sistem gigi dalam bivalvia? (:
Locality #5: Tanjung Jaga
Things to do here:
1) Identify the rocks and its minerals
[Hint: Link the rocks from Locality #2 and Locality #3.]
2) Find the contact points between the igneous and metamorphic rocks
3) Learn about roof pendants.
Remember these guys? Saccostrea cuccullata, we meet again. (:
Contact seen in a boulder. The darker, grey part is metaargilite and the white part is igneous (pegmatite.)
Kalau guna hukum potong-memotong, kita boleh tahu batuan mana paling muda, batuan mana paling tua. Can you tell which is which?
*
Roof pendant:
If I remember correctly... the story goes something like this:
Granit Gunung Raya merejah Formasi Jerai, part of Formasi Jerai atas granit tu terhakis and the rocks left behind macam tergantung in granite ah. Therefore dia dipanggil roof pendant. Sebab dia tergantung (macam pendant kat rantai ah) kat bahagian atas rejahan granit tu.
Feel free to Google the actual definition. I know I make no sense. (:
DAY 3
Locality #6: Pedu Dam
Semanggol Formation
Age: Early Permian - Triassic
Here you will spend about 2 hours hiking up a long and winded road. Seriously. Naik tinggi gila.
Batuan kat sini menunjukkan ciri-ciri submarine fan deposits. Kipas laut dalam. This means: jujukan batuan mengkasar dan menebal ke atas. This has to do with the environment of deposition of a submarine fan of course. Lagi dekat dengan punca, butiran terendap lebih kasar. Lagi jauh, lagi halus. Proximal, medial, distal. Ingat kah?
Halus... Granulitic sandstone...
Kasar... Konglomerat...
Sedimentary structure : Load cast yang dah tegak. So, arah mana memuda?
Locality #7: Bukit Larek
Semanggol Formation
Age: Early Permian - Triassic
Ada apa di Bukit Larek? Black mudstone, siliceous mudstone, tuffaceous rock layers and chert. Jalan start kat area yang ada black mudstone, berakhir kat tempat yang ada chert.
This picture shows slumping in chert / mudstone(?) layers; menunjukkan bahawa ada pergerakan/ canggaan sebelum batuan ini mengeras.
Locality #8: Pokok Sena
Kubang Pasu Formation
Age: Late Devonian - Early Permian
Kat sini boleh observe 3 formations in one place.
We start off with the Mahang Formation (mudstone, slate) followed by rocks of the Kubang Pasu Formation (chert, interbedded sandstone and shale, thickly bedded sandstone layers) and lastly part of the Semanggol Formation.
Tapi Formasi Kubang Pasu kat sini takde la besar mana outcropnya. Jalan sikit je after Mahang jumpa Kubang Pasu. Jalan sikit lagi dah jumpa Semanggol.
Sedimentary structures found : Load casts and flute casts. (In picture: Flute casts, displaced by faults.)
Lapisan batu pasir yang tebal-tebal...
Locality #9: Bukit Jabi
Kubang Pasu / Mahang Formations
All that's left of the Kubang Pasu Formation...
Dulu ada outcrop kat sini. Now dah naik kilang kayu. ):
Mahang Formation... Slate of different colours, representing different levels of weathering in the rocks. The white ones are very, very weathered.
These two formations are separated by a fault zone*.
(*Sesar Bok-Bak; palm-tree structure.)
DAY 4
Locality #10: Bukit Kechil and Bukit Kalong
Kodiang Formation
Age: Permian - Triassic
This locality focuses a lot on Geomorphology. So, things to take note of: geomorphological features of karstic terrains and the materials that build them.
You should know at least 10 geomorphological features (says Dr. Jo.) Here's a few:
1) Stalactites
2) Stalagmites
3) Pillars
4) Caves and caverns
5) Sea notches
The building material? Reworked limestone, secondary calcite... also known as Travertine.
Other things to look out for:
1) Parallel lamination in crystallized limestone layers (we found this on a boulder tepi jalan.)
2) Intraformational breccia limestone
3) Calcareous mudstone with chert nodules
Here's a rough sketch of the area.
A bottle of acid would be useful to determine the type of rocks here. But do TAKE NOTE that not all rocks that react with acid are limestone. Bukan semua limestone kat sini! Ada unit klastik bawah limestone Kodiang.
Sebab hujan and whatnot, chemical weathering causes the calcium carbonate materials that make up limestone to wash over the surrounding rocks and in between cracks. So when it doubt, try la scratch/ ketuk pakai hammer (keras gila tu chert ah.) and observe the grains, feel them with your fingers (nak tahu mana sandstone, siltstone, etc.)
Faulting in the clastic unit underneath the Kodiang Limestone.
Locality #11: Guar Geteri
Kubang Pasu / Chuping Formations
Represents the upper part of the Kubang Pasu Formation. Consists of interbedded sandstone and mudstone. Interesting things to see:
Sedimentary structure : Ripple marks in sandstone.
Monodiexodina sp. ; a type of fusulinid. Macam beras basmati. Memanjang, around 1cm or so. Found in the fine-grained sandstone layers.
Locality #12: Guar Jentik
Setul / Kubang Pasu Formations
Lithology:
1) Setul Formation : Limestone, fossiliferrous black mudstone
2) Kubang Pasu Formation : Chert, sandstone, shale
The best part of this locality? The fossil-hunting session. (:
Oh yes. Masa ni la semua orang nampak macam pekerja lombong. Kalau tangan dengan kertas report tak hitam, tak menggali dengan betul ah tu. Orang yang muka sekali hitam tu memang mencari fosil bersungguh-sungguh ah, sampai muka pun hitam.
Fosil apa ada?* Brachiopods, some Nowakia sp., graptolites, stylolites and trilobites.
(*dalam kuiz ada mintak differentiate which fossils dalam black mudstone, which fossils dalam red mudstone. Sibuk sangat menggali yang hitam, tak perasan pulak yang merah. Tapi ikut buku panduan, the fossils found lebih kurang je. Dalam yang merah ada extra sikit: cephalopods.)
Some beautiful trilobite samples my friends dug up. I didn't get one. Oh well.
Dr. Zaiton is photgraphed here, standing in a fault zone which separates the Setul Formation from the Kubang Pasu formation. Batuan dalam zon sesar ni termetamorf secara dinamik.
Locality #13: Gua Kelam (TUTUP!)
Setul Formation
Age: Ordovician - Silurian
Banjir --- Jambatan runtuh --- Gua Kelam tutup, end of story. ):
Anyhow, kalau Gua Kelam buka - this is what we were supposed to do:
1) Identify morphology, underground drainage/river, chert nodules, travertine, stalactite and stalagmite
2) Spot some fossils! Malayaspira rugosa and Lytospira rectangularis (gastropods.)
DAY 5
Locality #14: Kiang Giap Quarry
Setul Formation
Age: Ordovician - Silurian
Lithology: Dolostone (lacks calcite, which is why this isn't a kuari simen. Kuari simen needs calcite!)
According to the buku panduan : "It consists of two cycles of thickly bedded dolostone and each cycle starts with extensively distributed dome-shaped stromatolites..." Don't ask me about the cycles. I'm just as confused as you are. But hey, here are the stromatolites. (:
See the domes? Stromatolites are also used as way-up structures. Domes show the way up.
Rejahan igneus yang menarik! :D
Slickensides are common here. This place has a number of faults. Dah berlaku banyak episod canggaan.
Calcite crystals. Ada yang halus, ada yang kasar. Most of them make up calcite veins, easily scratched guna hammer. Boleh jumpa kalsit gigi anjing (dog-tooth spar calcite.)
This isn't gold. It's Fool's Gold (Pyrite). Were you fooled? (:
Locality #15: Utan Aji (Kampung Binjai)
Kubang Pasu / Setul Formations
This is the bottom part of the Kubang Pasu Formation ; red shale and sandstone layer with lots and lots of fossils! (Setul Limestone is also present in the area.)
Fossils : Trilobites, gastropods, bivalves and crinoid stems.
My cephalopod, well-preserved with hints of suture lines and growth lines. (: Sampai Langkawi je patah, but I've glued it back together dengan gam gajah 90 sen. Hahaa
LANGKAWI
DAY 6
Locality #16: 'Pondok Nibong' (Teluk Tok Manap)
Machinchang Formation
Age: Cambrian - Lower Ordovician
Two outcrops here:
Outcrop 16A : Road-cut outcrop
What to observe: Large scale trough cross beds (sketch, sketch, sketch. Under close observation you will see how each trough cuts the other troughs.)
When sketching, remember to look at the 'gajah' from afar first before you draw a close up with the details and information needed. (:
Trough cross bedding in sandstone. Interpretation : Marine sand bars (Environment: Delta)
Outcrop 16B: Beach outcrop
There are two ways down:
1) The good old natural way, turun slope pegang ranting-ranting pokok...
2) Turun longkang with the aid of a rope.
(If you have a tendency of rolling/falling/flying down-slope, I suggest you go for option number 2.)
Here you will find smaller cross-beds than that found at the road-cut outcrop. The cross-beds are not only smaller, the grains are also coarser. There are channel lag deposits here (large clasts deposited in fast currents) arranged at the bottom of each cross bed. Interpretation: River channel deposits.
La la laaa. Saccostrea cuccullata! They're everywhere in this fieldwork. Aiyoo. Hahaa.
The islands you see in the distance are part of Thailand. Not Malaysia. The island far left in this picture shows the figure of a cuesta in which the steeper side is made of sandstone which withstands weathering and the gentler side is made of argilite which is less resistant to weathering.
*
-Outcrop 16A : Road-cut (Kat atas) - Marine sand bar, delta
-Outcrop 16B : Beach (Kena turun bawah) - River channel deposits
Relate both outcrops. How did the water level change? Did it change? Did the area undergo transgression or regression?
(Sendiri pun tak ingat actually. Hence, tanya kepada anda semua. Hahaa)
Locality #17: Pasir Tengkorak - Tanjung Buta
Machinchang Formation
Age: Cambrian - Lower Ordovician
This locality focuses a lot on sedimentary structures. There are plenty here. (:
There are mini-deltas and mini braided rivers in the sand by the beach. Senang sikit nak tengok proses-proses yang terlibat, live depan mata dengan air mengalir, without having to look at the large scale rivers and deltas. (:
Behold, the wall of all sedimentary structures! Jeng jeng jenggg.
Load casts, ripple marks in sandstone, parallel lamination in mudstone (also: flame structures and slumping beds; not photographed.)
Pseudonodules! Jasad pasir yang nampak macam nodule hasil hakisan lumpur yang mengelilinginya.
Tafonis. Macam honeycomb! (:
Lenses of sandstone in mud - Lenticular bedding
Locality #18: Pasir Hitam
Weathered granite
Pasiaq hitam nohhh. Haha :D
Yes, the sand IS black! :D
This is due to the presence of tourmaline and ilmenite which are products of weathering of the Gunung Raya granite. Here you would have to find coarse grains of black sand and differentiate between the tourmaline and ilmenite grains.
Tourmaline grains are prismatic minerals with a glassy (vitreous) lustre while ilmenite grains appear a bit dull. Occasionally you will find bits of iron.
Don't feel bad if you can't find any ilmenite because the black sand is 80% tourmaline anyway. (:
Locality #19: Air Hangat - Durian Perangin
Singa Formation
Age: Devonian (?) Carboniferous - Early Permian
This locality consists of the upper part of the Singa Formation. There are some fossils here, mainly bryozoan colonies and brachipods. The brachiopods are said to be cold climate brachiopods - which show that we were once a part of Gondwanaland.
Lithology: Limestone, sandstone and shale.
Ripple marks in sandstone.
Polypora sp. (Bryozoa) in limestone.
Fenestella sp. (Bryozoa) in limestone.
Bando productus Waterhouse in the shale unit of the formation.
Locality #20: Belanga Pechah
Chuping Formation
Age: Permian - Triassic
The rocks here are highly fractured due to the dynamic deformation of the Kisap Reverse Fault.
This fault (Kisap Fault) separates the Setul Limestone and Chuping Limestone. Upon entering the outcrop area, Chuping Limestone will be on your left and Setul Limestone will be on your right. You will be walking on the fault zone. (:
A lot of jagged rock and fault breccias can be found in this highly deformed area.
The angular clasts can be really small...
...and some clasts can be big.
Here's a sketch* relating the Gunung Raya granite, Singa Formation, Chuping Limestone, Setul Limestone and the Kisap Fault. Kalau pay attention masa fieldwork, this diagram will make a whole lot of sense. Kalau rasa lost tengok diagram ni, feel free to ask. (:
*Sketch courtesy of Ahmad Faiz, from Prof. Basir's explanation. Thanks! Heehee.
DAY 7
Locality #21: Tanjung Mali
Singa Formation (diamictite)
Age: Devonian (?) Carboniferous - Early Permian
This locality is part of the Kentut Member of the Singa Formation.
The main attraction here is the dropstones of course. These dropstones were carried by floating icebergs. Nak kenal dropstone senang - the parallel layers of mudstone/siltstone akan melengkung ikut tempat yang batu tu jatuh. Macam kena penyek. The layers bawah dropstone tu nampak closer together, rapat-rapat.
Faulting in rock layers.
Pinch and swell / Boudinage
Dropstone! This one is granite from far, far away. (:
"Eh, kalau dropstone tu deposited by melting icebergs, iceberg tu mai dari mana? Malaysia ada iceberg ka?"
Well, Malaysia was not always at the equator and the climate wasn't as temperate as it is now. The presence of these dropstones show that we were once in a glacial environment where everything was cold, way above the equator in this big continent called Gondwanaland. (:
Locality #22: Penarak
Contact zone between Granitoid and Setul Limestone
Last locality. Last quiz. (:
This locality shows the contact between granite and limestone. As a result of the granite intrusion, the limestone became metamorphosed, forming marble.
The bedding in limestone is still preserved, suggesting that the type of metamorphism here is contact metamorphism (high temperature, tekanan tak memainkan peranan sangat.)
Close-up of the minerals in granite. We have the usual quartz and feldspar with some tourmaline and mica.
There are marble of different colours here. Pure marble (with no impurities) is white. The different colours are from the different elements present in the marble. (Blue - Manganese, Green - Ferum.) The marble here is low-grade marble. Tak perlu la nak korek sangat sebab orang pun tak nak marble of this grade. Hahaa.
So, that pretty much wraps up the Northwest Peninsular Malaysia fieldwork!
This is Suraya Hazim, signing off.
Thank you for reading my ramblings.
P/S: Kalau ada fakta salah bagitau ASAP so I can correct them. Thanks!
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