Sometimes the difficulties of taking photos from a moving bus are a bit of a boon. We left the Kangaroo Island Animal Park and drove west through Flinders Chase National Park. Although the landscape wasn’t utterly barren and it’s said that Australia’s bush recovers quickly, the fire’s remnants were still visible. I took no photos.
It would take us an hour or so to reach our first stop at a place called Remarkable Rocks. Seen from a distance
they looked to me perhaps interesting but not particularly remarkable. (This photo also shows the mix of burned and recovering bush.) Perhaps they are geologically remarkable. Let’s take a look.
These are granite rocks comprised of black mica, bluish quartz, and pinkish feldspar. While this composition of minerals is common in quartz, this color combination isn’t. So let’s score one point for remarkable.
Their formation began 500 million years ago (MYA) when molten rock bubbled up to the Earth’s surface and cooled into granite. The granite was initially located about 10 km below the surface. Tectonic movement through the breakup of the supercontinent Gondwana uplifted and exhumed the rock exposing it to the Earth’s surface. Over time, the process of spheroidal weathering combined with continuous erosion by the wind and rain to wear away the softer rock eventually exposing the harder granite and resulting in the giant and oddly shaped boulders we see today that are
sitting atop a lava dome. What you see in the photo above is an example of tofoni (also called cavernous) erosion. When water brings dissolved minerals to the surface, the physical and chemical processes that are part of spheroidal weathering and winds dry the water, the minerals form crystals that force small particles to flake off the rock. Eventually, large cavities with a cavernous shape form because the surface layer of the rock is harder than the interior. Rocks that have more granite near their surface erode more slowly (a process called differential erosion). This provides geologists more opportunities to study the long-term effects of weathering on granite formations and tourists more opportunities for interesting photography.
There’s one other element (remarkable or otherwise) to note about these rocks perched some 61 meters above the ocean below and that’s their orange coloration.
Although visible in the photo, these colors, caused by a combination of iron minerals in the granite and the golden-orange lichen growing on the surface, are said to be quite intense at sunrise and sunset. This is said to add to their remarkable appearance but I can’t attest to that because we were there in midday.
Admirals Arch
(All the walls fall inside our slow moving storm.)
We left Remarkable Rocks for the exceedingly long 10 minute drive to Admirals Arch another famous formation in Flinders Chase NP. In its beginning, the arch was a cave in the coast cliffs with the typically small entrance that most caves have. But the nearby ocean, relentlessly flexing its erosive power
weakened the rocks in the cliffs creating ever widening cracks. Perhaps a little jealous of the ocean, other forces of erosion such as wave action, forced air pressure, freezing-thawing cycles, and biological processes joined the effort of enlarging the cave and its opening. (In certain environments, algae decay joined by the normal biological activities of bacteria and invertebrates can contribute to the weathering process.)
Several factors make Admirals Arch unusual among arch formations. Unlike most arch formations such as those in Arches NP in Utah that are formed from only eroded sandstone, Admirals Arch formed at the junction of two distinct rock types – porous limestone and harder Cambrian period sediments that form the base of the arch and, like the Remarkable Rocks, date to at least 500 MYA.
Marine arches are relatively common around the globe. (Think of Malta’s Azure Window or La Catedral in Paracas along the coast of Peru {both sadly collapsed} that you might have seen in other entries in this blog and that you can see in the links above if you haven’t.) While other erosional forces played supporting roles in the Arch’s formation, it was ocean waves that had the lead in breaking through the original cave structure.
Finally, as you’ll see in the photo below, Admirals Arch has two other exceptional and distinguishing elements – stalactites on its ceiling demonstrating that it was, indeed once a cave. This contrasts with its very smooth floor where the roughness has been worn away by the waves. (We descended about 100 steps to a platform several meters above the floor so I can’t personally attest to it smoothness.)
As for its name, no, Matthew Flinders never achieved the rank of admiral so if you think that the name Admirals Arch is another way of honoring Flinders you’ll have to discard that supposition. There’s one fact I can tell you about the name and that is that it was officially accepted by Land Services SA in 1989. It’s likely that locals had been using that name for some time before that. The one bit of naming conjecture I can find for the reason is that it bears a resemblance to London’s Admiralty Arch. I’ll leave it for you to decide. Admiralty Arch London.
[From Wikipedia By Diliff – Own work, CC BY-SA 3.0]
Admirals Arch Kangaroo Island.
Back east to Emu Ridge
I have to admit that when I saw our day’s final stop at Emu Ridge Eucalyptus Distillery my first thought was wondering what liquor distilled from eucalyptus might taste like. At some points in my past I’d had Hall’s Mentho-lyptus cough drops but they always tasted more of menthol than anything else. I generally don’t consume distilled spirits so I was rather relieved to discover that this distillery produces eucalyptus oil from the leaf of the Eucalyptus cneorifolia or Kangaroo Island narrow-leaf mallee. They also produce or market tea tree oil, honey from the only pure strain of Ligurian bees in the world, and, perhaps sadly and almost certainly controversially, emu oil.
Let me start with the last. You can read this statement on the Emu Ridge website,
Emu Oil has been used by the Australian aborigines for thousands of years. They have relied on its consistency of healing and therapeutic qualities to survive Australia’s harsh climate.
From the number of studies conducted it has been shown that Emu Oil really does work. It is one of natures finest emollients and moisturizers. Its well known in the pharmaceutical industries, the Institute of Sport in Canberra, and is currently being used worldwide by sporting bodies.
In their FAQs they state rather benignly that, “Emu oil is taken from the fat of the emu, the adipose tissue.” What they’ve omitted is that the bird must be killed to extract the oil meaning that there’s a qualitative difference between the subsistence hunting practiced by the Indigenous Australians and their use of as much of the animal as possible and today’s farming of the birds, likely for their meat with the oil extraction being a profitable adjunct. An adult male emu will produce four to five liters of oil. Emu farming is said to have a fairly large carbon footprint but it’s probably better for Australia because the bird is native to the country. It may be that the emus in question are ethically raised and the process is little different than farming other animals for their meat. Using the fat as a by-product of slaughtering them does maximize the animal’s utilization. I leave a decision on the ethics of this practice to you.
In most other areas, this family owned business seems to have a high regard for the environment. They use no chemicals or sprays, harvest the leaves on a rotational basis to extend the useful life of the trees to a century, and distill the oil using traditional methods. They seek to minimize waste by, for example, reusing boiled leaves from the old cook as a fuel for the fire in the distillery, and also as sterile mulch. Their shop, as you saw in the post, The inscription on the baker’s shelves is open not only to the public but to kangaroos – adults and joeys – as well.
Here’s a brief video showing the history of eucalyptus oil production and of Emu Ridge
and here are my other pictures from the afternoon.
We finished our tour with dinner (perhaps a haloumi burger or a some sort of salad for me) returning to the hotel in Kingscote to end a busy but relatively easily paced day. And any day is a good day when you’ve hugged and been hugged by a koala.