Pseudokarst Granite

Ubin Jetty at low tide, exposing large granite boulders commonly known as "flute rocks" with vertical grooves or "flutings". Photo by November Tan

As a person arrives at the Pulau Ubin jetty, the first thing that may capture their attention are the large granite boulders that line the coast of the island. These are we commonly referred to as flute rocks. It has always been mentioned by various sources such as Dr Chua Ee Kiam that these rocks are really unique features and has been described in various books about Singapore such as Edmund Waller's "Landscape Planning in Singapore". In fact, according to this quote from a book on coastal features around the world by Heather Viles and Tom Spencer (1995), these flute rocks are indeed rare features even around the world.

"Granite cliffs in Singapore with its presence of deep 'pseudokarstic' fluting on the granite, extending way below present sea level, bears witness to the antiquity of their formation." (Page 117)

There are also mentions of Pulau Ubin's pseudokarst features in a journal article by H.M. French and M. Guglielmin (2002) on "Cryogenic grooves on a granite nunatak, Northern Victoria Land, Antarctica" published in Norsk Geografisk Tidsskrift.

Our coastal features does appear to be well known around the world. Not only are these granite features popular, we also appear to be along the ranks of famous coastal locations in terms of having a rock shore environment and shore platforms as again Viles and Spencer (1995) writes that "shore platforms are found in many parts of the world including Australia, Antarctica, Norway and Singapore." (Pg 111)

They also quoted Swan (1971) that while most cliffs in the humid tropics are not being undergoing active erosion activities, Singapore is one of such unique exceptions where "active" cliffs are found on relatively exposed coasts. (Swan, 1971)

These brings to mind the few remaining rocky shore beaches and cliffs that remains in Singapore today, such as that in Labrador Park, Changi and Sentosa. Hopefully these cliffs would remain for some time to come along with the rare pseudokarst granite "flute rocks" of Ubin.

Bibliography:

Viles, H. and Spencer, T. (1995) "Coastal Problems: Geomorphology, Ecology and Society at the Coast" Edward Arnold

Swan S.B.StC. (1971) "Coastal Geomorphology in a Hot Humid Low-energy Environment: The Islands of Singapore" in Journal of Tropical Geography, Vol 33

French, H.M. and Guglielmin, M. (2002) "Cryogenic grooves on a granite nunatak, Northern Victoria Land, Antarctica" Norsk Geografisk Tidsskrift