Sunday sand: a nuptial arena

 
This last summer, the wedding of the daughter of friends of ours took place on North Stradbroke Island, off Australia's Queensland coast. A dazzling expanse of dunes and beaches, it’s considered to be the world’s second-largest sand island (a quick quiz, no prizes – what’s the largest? Hint: it’s not too far away). It’s only natural that sand contributed to the memories of the nuptial event, and that a sample of such would fall into my hands, almost pure quartz, the grains sparkling with a subtle range of hues and shapes.

 
It’s tempting to view North Stradbroke as a barrier island, but it probably isn’t. The core of the island is made up of old sand dunes that were reworked and redistributed as sea level rose and fell during the ice ages. This process goes on, dramatically and dynamically today, the coastal area and swirling offshore sand banks constantly shape-shifting with time, the seasons, and storms. Indeed, the island only became an island little more than a hundred years ago as a result, it would seem, of a strange conspiracy of circumstances. In a storm of 1895, a Scottish ship carrying (what else?) whisky and dynamite, was wrecked on the narrow strip of sand that then connected what is now the island to the coast to the south. The whisky was, of course, salvaged, as was the dynamite which was stacked up in the dunes and intentionally detonated. The explosion caused some considerable damage and destroyed much of the vegetation holding the sand together, and the next major storm ripped into the beach and opened up the Jumpinpin Channel. A little time playing around with Google Earth historical imagery will demonstrate the ongoing dynamics of the sands around the channel which is steadily migrating northward; an entertaining documentation of coastal change, together with old maps and shipwreck legends,can be found here.

So, a long-lived and spectacular playground of sand; but, along with the attractions come problems, for, amongst the old dunes, the natural processes of winnowing and segregation have produced placer deposits, concentrations of grains whose mineralogy is of commercial interest. For sixty years or so, the sands of North Stradbroke Island have been mined for the minerals rutile, zircon, and ilmenite, concentrated in these placer sands. Rutile is primarily titanium dioxide, and ilmenite is an oxide of iron and titanium, and so these minerals are a source of titanium metal, but, even more importantly, its oxide, which is the base for multiple applications as a white pigment. Your skimmed milk may be thus whitened and your refrigerator may owe its brilliance to North Stradbroke Island.

But sand mining is an unsightly business, conducted on a huge scale: around 50 million tonnes of sand are mined each year to produce 500,000 tonnes of minerals.

 
The State Government now has a plan (not without controversy because of the economic and employment implications) for closing down the mining operations and turning more than half the island into a State Park by next year, and 80% by 2027. Details of the plan and the controversy can be found on Queensland Government website and in articles from the Sydney Morning Herald and the Courier Mail.

 
As is so often the case, the tensions between commerce and communities, landscapes and livelihoods, result in a complex of grey areas for policy-makers to work through. But it is certainly inarguable that North Stradbroke Island’s sands create a stunning and unique landscape, worthy of our respect and preservation.

 

 

Comments

[Malcolm]

I believe the largest is Fraser Island, couple hundred km's north of Stradbroke. Luckily it has a state park.

[Sandglass]

Correct! Sorry about the lack of a prize, but welcome to the Geoblogosphere!

[Richard Bready]

I would dearly love to see a Strine version of Whiskey Galore as Whisky and Dynamite, the added term lending itself to the local vowels.

[Mike Ricks]

I recently emailed Michael with a cheerful comparison of the volume of sand in the Dubai "World" project to that which we've mined on N Stradbroke Island over the last few decades, NSI coming out on top as the 8th wonder of the world! I was delighted to get a reply from Michael eventually when he extracated himself out of the deserts of WA. The legend of the explosion at Jumpinpin causing the ocean to break through I always considered a bit of a stretch, knowing as an old miner that the sand would absorb most of the explosion, or at least most of it would be lost upwards, but Michael makes a good point, that the vegetation would have been destroyed, probably beach spinifex or casaurinas, and that was enough to let the next storm charge through. The sand islands here are very mobile, Bird Island in Moreton Bay commented on by Matthew Flinders has disappeared completely in the last decade. By the way I wish all textbooks were as readable as "Sand" when I was a student, no end of interesting stuff.