Gargantuan forces shaped, lifted Sabah from the deep: Don

Published on: Sunday, April 04, 2021

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Prof Felix Tongku shows how Sabah/Borneo is compressed by ongoing movements from the Eurasian plate, the Australia plate and the Philippines Pacific plate.

IRRESPECTIVE of our racial background, everyone born and bred in Sabah feel deeply proud of Sabah – “Mountains High and Oceans Deep” – a favourite mantra which Dato Dr Tengku Adlin was fond of describing a world-class real estate of utmost beauty, in his heydays whenever he presented Sabah’s case to world tourism.

But do we know “in the beginning or 80 to 130 or even 20 millions years ago”, Sabah was not and never mountains high but only oceans deep!?

In other words, there wasn’t always a “landed Sabah”. Everything was underwater once.

Or maybe some of us had heard about that, but as the Hakka people call it –‘Mung char char’ – blank on the slow but gigantic imperceptible geological forces that shaped a gem of a “Mountains High and Oceans Deep” present day Sabah which is not only marked by an utterly inspirational iconic Mt Kinabalu in the West Coast but also the epic jewel of Ocean Deep – Sipadan, in the East Coast.

So, keep your fingers on this hard-to-fathom poignant point, that is, millions of years ago, a landed Sabah never existed.

Prof’s colourful graphics reveal Sabah as an ‘Accreted Terrane’

So now look at the graphic entitled “Accreted Terrane” provided to Daily Express by famed local geologist, Professor Dr Felix Tongku.

“An accreted terrane is a fragment of crustal material (the proto- south China Sea Oceanic crust in this case) that have collided with another crustal fragment (the sulu Sea Oceanic Crust in this case) and permanently attached,” Prof Tongku explained.

What do you see?

Just look at the graphic cross section of Sabah which marks out where present day Capital City Kota Kinabalu is, where Mt Kinabalu (4,095m or13,431.6ft) is and where Lahad Datu is.

“That is the accreted terrane that makes up the land mass of Sabah which first started to surface in Lahad Datu or the east coast in around 90 million years ago, judging from the age of Madai Caves, and added up backward towards Kota Kinabalu,” Prof Tongku explained.

But he is quick to add that the subduction and accretion process applies to the whole of Borneo Island, not just Sabah.

Subduction, accretion and collision – the gargantuan powers that shaped Sabah

So what are the gargantuan geological powers that first formed and then later literally ‘lifted’ this wonder State Land of Sabah and Borneo from the Great Deep!?

Prof Tongku cited a combination of three: “Subduction, accretion and tectonic collision” – very slow imperceptible processes that took an estimated 130 million years and provided me with some of the most splendid graphics I have ever seen on the subject, after he had chaired Session One entitled ‘Unesco Global Geopark and its potential in Malaysia’ in the International Seminar on ‘Aspiring Kinabalu Unesco Global Geopark’ on March 25 in the Sabah Convention Centre, Kota Kinabalu.

So, if we are just looking at the cross section of Sabah’s accreted terrane which first started forming and surfacing from east coast Lahad Datu and moved backward towards Kota Kinabalu, you might have to agree that this prime real estate Sabah is a “gift” from China aeons ago.

In the second set of graphics on Tectonic Setting, Prof Tongku provided a telling one paragraph that explained what happened over the aeons.

“The accretion of ancient oceanic crust (130 million years old) known as the proto-South China Sea Oceanic Crust started about 85 million years ago and ended around 15 million years ago when the ancient sea closed.

“Plate tectonic collision which followed and continues up to this day raised the ancient oceanic crust to the surface,” Prof Tongku made this key point that landed Sabah actually emerged from deep sea only 20 million years ago!

But why does Sabah’s land mass start forming in Lahad Datu first and not Kota Kinabalu?

The answer is subduction and accretion go together starting in Lahad Datu and gradually moved across to KK.

Wonder real estate Sabah is made of sediments scrapped off form proto-South China Sea Oceanic crust!

But first, understand this. Accretion involves the addition of materials to a tectonic plate via subduction – the process by which one plate is forced down under the other and as that happens, sediments and fragments of crustal materials are scrapped off from the subducting crust.

So this is what actually happened – the Proto South China Sea oceanic crust which contained huge amount of sediments converged with the Sulu Sea Oceanic crust about 85 million years ago and the proto South China Oceanic crust subducted under the Sulu Sea Oceanic crust somewhere in the Lahad Datu area.

This led to huge amounts of sediments carried on top of the Proto South China Sea Oceanic crust being scrapped off in the Lahad Datu area first but remained submerged for millions of years.

This subduction and accretion process that moved from the Lahad Datu area towards Kota Kinabalu area from about 90 million years ago to about 20 million years ago when the hitherto easy subduction stopped as the proto South China Oceanic and Sulu Sea Oceanic Crust hit each other head on and sparked at tectonic collision, Prof Tongku noted.

“I was this tectonic collision about 20 million years ago that lifted the accreted terrane or sediments that were scrapped off from the proto South China Sea that became the land mass of Sabah we see today.

“Mt Kinabalu was not formed as a pluton until 15 to 9 million years ago,” Prof Tongku elaborated the whole tectonic process that formed and lifted Sabah from the great deep.

In one fell swoop, Prof Tongku provided Sabahans an acute insight to ply open a raft of very complex and opaque geology jargons that hide easy knowledge of the geology of Sabah for far too long.

Global Geopark has no meaning if….

So if 99pc of Sabahans had no idea how their wonder real estate came about, now they can begin to understand.

Otherwise, the proposal for a 4,750sq km Kinabalu Global Geopark area centred around the 754sq km Kinabalu Park World Heritage Site may mean little value to many people.

Again, as Adlin was once always fond of entreating his audience: “To know Sabah is understand Sabah; to understand Sabah is to appreciate Sabah; to appreciate Sabah is to love Sabah.”

When I heard in Emeritus Professor Dr Ibrahim Komoo said in the same session and same seminar the whole idea of a Global Geopark is to “enhance the international value” of the area maybe 16 times more than juts Kinabalu Park, with appropriate value-adding development in balance with conservation, I got the salient purpose but at the same time, I thought how can that happen if no Sabahans are interested or care, because of a fundamental ignorance of geology.

So, I felt as an individual winner of the Prime Minister’s Hibiscus Award and Daily Express as the Organisation winner of the same award in March 2018, we have a responsibility to help boost the success of any genuine initiative to raise the value of Sabah wherever that intention may be.

While geology is very hard to understand, we try our best, this time, with very explicit help of Professor Dr Tongku’s graphics and comments over the next few series of Sunday Special Reports.

So, in this Second of a series, we’ll just focus on the first of Prof Tongku’s key graphics how the “Subduction, Accretion and tectonic collision” process that lifted Sabah from the deep and expanded the brief explanatory notes on the notion of ‘subduction,’ ‘accretion,’ and terrane for an easy start to a journey of geological understanding.

So on Tectonic Setting, Prof Tongku gave us two sets of graphics

First set tectonic graphics: Subduction & accretion from three massive plate collisions

The first set of Tectonic Setting involves three graphics and one picture on the summit rock face of Mt. Kinabalu as follows with a brief two paragraph text on concepts of plate tectonic collision and the resultant subduction:

“Sabah is located at the junction of three tectonic plates in SEA (South Southeast Asia), Eurasia- Sunda Plate (4cm/yr), Philippine-Pacific Plate (10cm/yr) and India –Australia Plate (7cm/yr).”

(Note the arrows indicate the directions from which the three gargantuan tectonic plates move and are still moving and compressing Borneo – the Eurasian –Sunda Plate from the West; the India-Australia Plate from the South- southeast and the Philippine-Pacific Plate from the East!).

“Plate subduction and collision resulted in accretion of oceanic crust and deep water sediment and formation of mountain ranges in Borneo.”

Second set Tectonic graphics – Accretion followed by tectonic collision lifted Sabah

As expanded earlier, we have expanded the lone paragraph explanatory note attached to his second Tectonic Setting graphics on the concept of accretion that goes with subduction:

“The accretion of ancient oceanic crust (130 million years old) known as the proto –South China Sea started about 85 million years ago and ended around 15 million years ago when the ancient sea closed.

“Plate tectonic collision which followed and continues up to this day raised this ancient oceanic crust to the surface.”

Daily Express feels satisfied we have overcome the struggle to understand the baffling geological forces that shaped Sabah.

Tectonic setting map cross section shows how the proto-South China Sea Oceanic crust (left) subducted below the Sulu Oceanic crust, caused sediments be scrapped off starting at Lahad Datu and later a tectonic collision 20 million years ago. This collision lifted the accreted terrane from Lahad Datu towards Kota Kinabalu be lifted above the sea.

Tectonic setting evolution.

This graphic shows Eurasian moves 4cm/yr eastwards towards Sabah. Philippine Pacific plate moves 10cm/yr westwards and Australia plate moves 7cm/yr northwards.