Monday, July 22

The sculpturing of Mount Kinabalu


ONCE SNOWCAPPED: During the Eurasian Ice Ages 1.4 million to 10,000 years BP, Mount Kinabalu was covered by an ice cap.

RUGGED: St John’s Peak at Mount Kinabalu.

ADMIRING the sheer size of this mountain from several vantage points in Sabah, it was only in Kundasang that my eyes focused on the crenulated notches on the bare granite skyline and on the mounds of small forest clad hills on the lower slopes.

How does one explain the rugged peaks of Mount Kinabalu, symbolised by such wonderful names as Donkeys Ears, The Rabbit, The Ugly Sisters and the peaks of St John, Victoria, King George, Tunku Abdul Raman and the South and North Peaks? Yet, what of Low’s Peak and Low’s Gully?

From their extensive research on the mountain’s superficial deposits, Koopmans and Stauffer, at the University of Malaya, in 1966, estimated that during the Eurasian Ice Ages (the Pleistocene period in geological time) 1.4 million to 10,000 years BP (Before the Present), Mount Kinabalu was covered by an ice cap, 5km square in area.

From the edges of the ice cap ice lobes in the form of glaciers flowed down slope exploiting fault lines in the underlying granite-type rock. Slowly but surely the loose rocks embedded and frozen into the base of these glaciers abraded the granite surfaces over which they rode.

Evidence of glacial erosion may be seen today in the striations (chisel-like scratches) in the granite surface zigzagging across the upper plateau surface.

Through the pressure of the overlying ice, the rocks embedded in the base of these glaciers frictionally sanded and eroded the bedrock.

Interestingly these striations bisect each other at distinctive angles suggesting that at different stages of the Pleistocene era the glaciers on Mount Kinabalu came from different directions.

The deeper scratches are relics of more recent glacial advances and the shallower striations from earlier ice advances. It is likely that ice exploited a major fault in the granite that led to a huge icefall in the form of a glacial spillway from the ice cap, thus creating the 1,500 metre sheer drop of Low’s Gully, best observed from Low’s Peak.

The smoothness of the upper mountain, in the area of the fixed ropes, and the glacial shutes where the ice spilled downwards add further evidence of glacial erosion.

In stark contrast, the jagged skyline, best observed on a clear day from Kundasang or Ranau, poses yet a separate explanation. At the peak periods of the Pleistocene glaciations the rock protuberances of Low’s Peak, Donkey’s Ears and The Rabbit were all above the uppermost level of the ice cap.

Such upstanding features are known as nunataks (an Inuit term for bare rocks extending beyond the upper limit of the Greenland ice cap). These peaks experienced freeze-thaw action by night and day, when in daytime, the ice in the cracks in the granite melted only to allow the water to trickle deeper into a crack.

At night-time the water refroze with the new ice expanding by 9 per cent of the water’s volume thus widening the crack. Repeated freeze-thaw cycles shattered the granite into angular shaped fragments.

Possibly this continues today, as I have seen a thin layer of ice at 5am on an April morning. Near the summit of Low’s Peak there is evidence of fresh scree slopes or felsenmere, bearing witness to frost shattering even today.

Another explanation of the jagged skyline is possible. In 2013, Drs Knight and Grab, at Wits University Johannesburg, suggest that the jagged peaks in South Africa’s Drakensberg Mountains are the product of lightning strikes which have blasted rocks apart.

There they found that lightning has hurled boulders weighing several tonnes over a distance of 10 metres or more leading to landslides. Could this have occurred on Mount Kinabalu given the frequency of tropical thunderstorms?

In the later stages of the Pleistocene glaciation, small corrie or cirque glaciers in armchair shaped hollows ate back into the back wall rock of these depressions into which small bodies of ice remained.

Such semi-circular hollows can be seen near Low’s Peak, at King George’s Peak and beneath three other peaks. The back walls of all five cirques face between northwest and northeast in direction.

Exactly the same orientation of cirques occurs in highland areas in the United Kingdom and in the Swiss Alps.

Simply by day time these would have been in the shade of the sun’s rays thus allowing snow to accumulate from year to year and to survive the higher temperatures.

Some melting occurred, by day, on the darker rocks above the ice, only to freeze at night to shatter the rock surface.

This shattered rock melted through the ice to become embedded in the base of such a small glacier and as an abrasive tool cut the bowl shaped depression even deeper as the ice flowed downslope and out of its confines through pressure and gravity.

Around 10,000 years BP the gradual melting of the ice cap began and continued until 3,000 years BP.

As the tongue-like glaciers melted morainic deposits were dumped in the form of a terminal moraine just below Panar Laban, near to Paka Cave. Here angular rocks bulldozed by the once advancing glacier are seen.

It is possible that there are yet, undiscovered moraines exist on Mount Kinabalu and are either inaccessible today through vegetation cover or have been remoulded by subsequent landslides and erosion forces.

As the ice cap slowly melted gradually material from the glacial deposits slid downslope to create the Pinosuk gravels which are to a depth of 140 metres on the Pinosuk Plateau, thus flattening the landscape there.

The material in the Pinosuk gravels is ill sorted, consisting of clay, silt and angular fragments of granite – the latter bearing witness to ice action and the former the result of melt water. The plateau has subsequently been dissected by rivers, creating steep sided gullies.

Whilst the Summit Trail is readily accessible for the reasonably fit, there is much research for geomorphologists to explore beyond the well-trodden paths to locate, map and analyse hidden glacial deposits.

Today, Mount Kilimanjaro at a similar latitude to Mount Kinabalu, but 4 degrees south of the Equator, and at an altitude of 5,895 metres is experiencing the rapid melt of its glaciers resembling what possibly happened in Sabah some thousands of years before.

With the sight of a thin layer of ice on the Sacrificial Pool, pull on another layer of clothing, get to the summit of Low’s Peak just at first light to see the mists in the valleys below.

Imagine yourself on this nunatak when an ice cap once smothered the fixed rope areas below. Look across to the silhouettes of the other nunataks and marvel at their descriptive names.

Turn your eyes downwards and imagine the lines of the mist below now demarcating where glaciers once flowed. Why? You have been transported back to the glacial history of this mystical mountain.

A few minutes later the sun rises and you are back to reality to see in the distance the South China Sea in one direction and the awesome drop of Low’s Gully just to your right hand side.

For further reading: ‘Geomorphology in Kinabalu Summit of Borneo by C Lynne and LC Myers (1978); ‘The Geology and topography of Kinabalu National Park’ in The Malayan Nature Journal Vol. 24 by DV Jenkins (1970-1971); ‘Glacial Phenomena on Mount Kinabalu’ by BN Koopmans and PH Stauffer (1967); and ‘Kinabalu Summit of Borneo’ by KM Wong and A Phillipps (1978).


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