August 5th 2013
Massive rock rolls into popular Island swimming hole
Sometime in the last month, the earth moved above Magnetic Island's settlement at Arcadia when a massive granite boulder went crashing through about forty very steep metres of bush, coming to rest in the bed of a very popular swimming hole on Peterson Creek.
Retired airline pilot, Ron Brennan, of Arcadia, discovered the repositioned boulder last Friday. He alerted Magnetic Island’s rangers and Magnetic Times. Ron, who visited to spot to watch birds gather to drink at some of the small remaining pools of water, guesses, from the remaining green leaves on smashed vegetation, that it came down in the last month. He is however astonished at the unusual odds of such a massive boulder falling directly into such a popular swimming hole.
"Four generations of my family have swum in the hole. My parents swam there in the 1930s and there is an endless stream of backpackers going there in the wet season. Even greater odds were involved, Ron believes, in the fact that the rock came down during the dry season. "The rock falls are usually during the wet when the ground is soft," he said.
"It would have made a hell of a mess if people had been there!"
Most locals will know the rock pool on upper Peterson Creek, as a welcome, shady, option for stinger-free splashing during the wet season. The pool has been modified over many years with a bit of rock and cement-wall work, which Ron says was done in the mid 1950s. There are also two, well worn but worn well, rope swings hanging, now, not so enticingly from a branch above.
The old path which had been reinforced many years ago with star pickets has also been destroyed by the rock's journey.
Fortunately there is a lovely although somewhat shallower pool just twenty metres below the recently modified ‘rock’ pool for sweaty wet season bods to bath in.
Just how and why the boulder decided to fall when it did will be a matter for ongoing conjecture. Perhaps one of the many local rock wallabies hopped onto the loose monolith one too many times. But, after a scramble up the hill one finds the rocks the boulder formerly rested upon to have only been scraped at a couple of spots by the departing tor. This suggests it had few and small contact points with its companions. During its rapid downward journey the giant stone smashed down the scrub and a tree before collecting a lower neighbour, just above the access path, which fell, with it into the dry pool.
"Its time had come" said Ron.
On impact the boulder split in two and will now begin to erode for further millenia slowly losing its sharp broken edges to exfoliation and the efforts of seasonal creek flows.
With balancing granite boulders one of its great natural attractions, Magnetic Island is of course no stranger to rock falls. Following ex-tropical cyclone Sid in 1998 and a huge amount of rain a ‘debris-flow’ thought to be eight times larger that the landslide which buried buildings and people at Thredbo, occurred above the International Resort in Nelly Bay, damaging some rooms which were, fortunately, unoccupied.
To see more of the graphic images of the big rock, where it came from and where it landed visit our Magnetic Times facebook page (click here)
Story and photo: George Hirst