Wednesday, 19 September 2012

The Blessings of Limestone - Part 1


Limestone formations, Mammoth Cave WA

Chemistry was never my strong suit at school, although it caught my attention periodically, so to speak. That was particularly the case when chemistry leaked out of its beakers and into the real world. Calcium carbonate (CaCO3), for instance, could become limestone. And to me, back then, that meant caves and adventure and beauty and wonder.

All that and more came to mind during our visit to the Margaret River region. Anyone familiar with the area is likely to think of wine, or forests, or surfing, perhaps even caves. Each of these, in its own way, owes something to CaCO3. For a start much of the area between Cape Naturaliste and Cape Leeuwin is underlain by a thick layer of limestone built up from the reprocessed remains of shells and other sea creatures


Limestone outcrop, Hamelin Bay, WA 

The boon for surfers is that the limestone can form offshore reefs. When the consistent Indian Ocean swells hit the reefs and bomboras at places like Prevelly and Redgate, they become long breaking waves that attract surfers from around the world. It's a perfect blend of physics and chemistry


We spend a couple of hours at Gnarabup Beach, a relative nook compared with the long open strands that characterise much of this coast. It's mid week and there are only a few surfers about. Most are trying out "The Bommie" or Margaret River Main Break at nearby Prevelly. We're just casual swimmers intent on a warm loll-on-a-beach, so we head for Gnarabup. Its golden limestone sand, twice-recycled shell sediment, gleams and glares between thick wadges of sea weed. The water is a translucent azure.


As we settle on the sand a surfer starts paddling out from the beach. He stands up on his board, using a long paddle to propel himself. We're intrigued. It's the first time we've seen a stand up paddle board close up. The wet-suited rider - part gondolier, part surfer - poles his way around the smaller in-shore waves. With each stroke he lifts the end of the inverted heart-shaped paddle clear of the water, taking nearly twenty minutes to negotiate his way out to a reef break at least half a kilometre offshore.


By that time most of us would have collapsed from exhaustion, but he stands on his board patiently. Occasionally he paddles calmly this way or that, all the while checking, Ahab style, for the signs of a good swell. He sees one, pivots his board, paddles hard. His speed surprises us, as he poles his way from the foaming crest of a 2 metre wave onto the clean curve itself. For a few seconds he cruises diagonally down the wave, the paddle his rudder. He is on the wave for maybe ten seconds before he runs out of wave. He eases up and over the left shoulder of the spent wave, and paddles back to watch for more.



Stand up paddle board rider, Gnarabup, WA 

We return to Prevelly and Gnarabup a few days later. It's high tide and the swells are larger. Only a few brave souls are trying out the main break. This time we watch a sea kayaker getting ready to launch from the beach at Gnarabup. He leaves his kayak high on the sand and goes back to his car to leave some gear.
We've been watching large sets coming through at intervals, and one comes while he's away. It surges up the beach, lifts and turns his white kayak and sucks it seaward. I rush down to stop it travelling any further towards Africa. The owner returns and thanks me, and we chat about his plans. He intends to paddle around the breaks and head towards Prevelly before returning.

I watch for some time, wondering which way through he will choose. He heads towards the same bombora the stand up surfer used the other day. Today its mood is different. One minute it is calm, the next it throws up ferociously steep, curling waves. He sees it in time, jags left and rises over non-spilling section of the swell. I sigh with vicarious relief, then watch as he patrols the deep waters beyond the reef.


Thinking about surfing: Margaret River main break, Prevelly, WA 

I wonder whether he, or any of the region's wave riders, think of the mashed molluscs and crushed crustaceans that have left him this delectable legacy. Watching these men, mere motes in a vast ocean, I can understand why neither falls from or otherwise leaves their vessel. They are far more likely to be pondering sea creatures of the large and finned variety.





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