GRENACHE GEOLOGY TOP OF THE BOTTOM

It's not exactly a mountain this mountain of a man is standing on, but at 250 metres above the Gulf, he's about as high as old vine McLaren Vale Grenache officially gets. 

That's stonemason Carl Mills (right) with Hickinbotham/Yangarra Estates vineyard manager Michael Lane. 

They're on the top of the Clarendon Hills ridge, between the two grand old Grenache vineyards, Bernard Smart's 1921 model facing south on one side, the Hickinbotham 1961 lot facing north on the other.

Beneath Carl is about 150 metres of Maslin Sand - just about that formation's northernmost extreme. But the hole he's digging there in top of at all has hit a neat layer of riverbed gravels. Some would argue this is Kurrajong Formation. Way up there!

Which just goes to show, that in this geology, it never matters how far up you go, you never have to dig very deep to discover that not long back that spot was on the bottom.

Hickinbotham 1961, above, ready to prune; Wayne and Bernard Smart in their 1921 block across the track, just after they'd picked 2017 ... photos by Philip White
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This stuff, while not fresh dug and not nearly so drought-dry and dusty, seems alarmingly close in composition to what Carl's digging. But this is the Kurrajong Formation rubble at Roger Pike's Marius Vineyard, 15 kilometres to the south down the Willunga Fault, and a full 100 metres lower in altitude. Nuts. I thought Pike had the only bit of this. 

While the Kurrajong is all rubble, its composition varies from one end of the Willunga Fault to the other, depending on the strata above which have contributed to it.

More slices of rock doctor fruit cake to worry over.

Here's another example of Kurrajong, geographically between the other two, at Yangarra, with three lineal stromatolites found at the same location in the snap below. I have also discovered bits of fossilised wood here. 

But that's just baby stuff, recent wood: stromatolites are the surviving signals to us from the beginning of life on Earth, a billion (or three)  years before.
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Stromatolites. Fair dinkum. Tread soft. They'll getchaventchuly. I fondle 'em. Stroke 'em. They purr.

Never in my wildest did I think I'd find stuff like this within a kilometre of my snug hut.

Looking, looking ... 

While we're here, surfin on rocks, let's ride a Kurrajong. This is a dramatic example of a young one on the rise,  found through war correspondent Frederike Geerdink's tweets about Kurdistan. Whatever the composition of the original sandwich of the crust, it's got a big crack and one bit's going up relative to the other so big bits of it crumble and tumble and little tiny beautiful humans crawl on it making war like ants.
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I have no idea whether the Willunga Faultline and its escarpment was ever this dramatic, although I believe the range beyond has been of Himalayan altitudes, twice. Whatever the movie - let's make it! - our cliffs have all gone. Weathered. That side of the range, the eastern uplands, are still lifting, but they're eroding faster than they grow, leaving a long strip of Kurrajong along their piedmont. Not much left to go: no more Kurrajong coming down ... precious stuff, that.

Here's a Milton Wordley photograph of the escarpment from afar, taken nearly twenty years ago and published in our rockin picture book McLaren Vale - Trott's View (Wakefield Press 2007). Great swathes of that range have since been replanted to native vegetation by volunteers.


Which raises two issues worth chewing over. 

First, as the climate goes awry, have we put native veg on the uplands we'll need for viable viticulture at cooler altitudes in more appropriate, older, more stable geologies?

Will we soon be swapping those new western-facing plantings of native veg on the scarp for wetland variants on the streams slugging westwards across the black clay flats, where grapes are not much good, and often go unpicked? Vines on the human folds of the old slopes in exchange for native wetland forest with well-planned tiny-scale three-storey villages spread through them on the flats? 

Talk to me! 

Second, due to some sort of respectful oversight between mapping geologists Wolf Preiss (old rocks) and Bill Fairburn (everything else), we omitted the delineation of the Kurrajong formation south of Willunga to the Gulf on our beautiful geology map. 

Some of the McLaren Vale region's best grapes grow in this stuff. I call these disparate stalwarts the Faultliners. They live unmapped. But I know they're there. They know they're there.

The map has the Kurrajong pretty well right north of Willunga to Kangarilla, but south of the Willunga township it miraculously disappears. In reality,the Kurrajong runs right down the piedmont to the The Victory Hotel and beyond to surrender to St Vincent in Cactus Canyon.

Gotta fix that, comrades. Embarrassing!

My bad.

This needs urgent remapping before we reprint, eh folks?  

Properly approached, Leon Bignell and Tom Koutsantonis, the relevant cabinet Ministers, could knuckle down and get a budget to ensure the world-revered South Australian Geological Survey includes a permanent energetic mapping geologist to specialise in our wine regions and sort these little issues, no?

I suspect, after many attempts at organising this, that the authorities are sick of trying to deal with whingeing wine region councils, all of which are composed of local winemaking business people with vested interests: nobody wants to pay more money for better grapes. 

Science is embarrassing.

And geology is like a dime-store detective novel, yeah?  


The pervioust murks of it lie in my dream brainbyre diaries ... always another page to turn. Gimme!  

In the meantime, I wish we had more old vine Grenache in the Kurrajong. 

And just to confuse ancient issues, here's a piece of spruce I found a kilometre to the west of my joint where the Kurrajong meets the Maslin and aeloean sands and recent ironstone: a piece of tree, washed down there, long after it was stone, from mountains long gone. 

This tree grew on or near the Equator. Since then Australia has been to the South Pole to make Gondwanaland, and is now well on its big bounce back north, pushing toward India at the rate your fingernails grow. Talk about torque - we're pushing the whole of the Indonesian archipelago to leaky bits, and forcing the Himalaya up, so bits of the peak of Mount Everest are falling off.  

But this is just a baby from the Carboniferous - like 300 million years back. Stromatolites go back billions. Add one whole comma.

We're just lucky that when this tree grew, bacteria had not yet evolved to eat it and rot it away to petroleum gel. We got bacteria everywhere now. Things rot. Earth is not making fossilised timber anymore. But we have Grenache. Open. Pour. Consider. Is it too woody? Is that oak or stone cold spruce?

Is that monkey really wearing 3D spectacles?