Wednesday, August 14, 2019

Australia 2019 – Day 17 – Fraser Island


OMG, I am in total amazement overload! I take back anything I said about exaggerated claims on Fraser Island, which is absolutely mesmerizing. But let me start from the very beginning: I was picked up at Ingenia Holidays at about 7:45 am, in an Isuzu truck that had been rigged as an all-terrain vehicle for carrying about 16 people (when I was in Mongolia with Zoe I remember thinking that Isuzu trucks would be particularly well suited for such a task, and I am glad to say I was right). As it is, I got to ride shotgun, so all day I enjoyed the big front window.

After getting our group together we went to the ferry terminal, got on the ferry, and proceeded to see a school of dolphins coming out of the estuary and coming into the bay. The “bay” is really the lagoon formed between the mainland and the sand bar, and was first charted by my hero, James Cook, in 1770 (he actually thought it was a peninsula rather than an island). In the early 1800’s Scottish Captain Fraser shipwrecked on the seaward side of the island, together with his wife Eliza and the crew. The castaways were received by the friendly aborigines, and Captain Fraser had the unfortunate notion that he and the crew would travel to Brisbane to seek help, while Eliza Fraser remained in the island under the protection of the aborigines (transportation had brought the dregs of the British prisons to the penal ports of Sydney and Brisbane). Unfortunately for them, the aborigines along their path were not friendly, and the whole party got massacred. Luck had it that a convict managed to escape from the penal colony and worked his way north to the island, where Eliza Fraser convinced him to guide her to Brisbane, in what was a long trip full of wild adventures. Destitute as she arrived in Brisbane, she started telling her amazing stories about her adventures, made enough money to go back to Scotland, and spent the rest of her life milking her sensationalist tales (half of which were make believe). It is after Eliza that Fraser Island got its name.

The island is very different than say Padre Island, in that it is quite rugged, with the highest peak rising 250 m above sea level. It forms part of a littoral cell that starts in the rivers that reach the coast south of Brisbane, and is the fourth or fifth of a series of barrier islands that were formed by beach drift to the north. The northern end of Fraser is the end of the cell, after which sand cascades down into the deep sea floor. The Great Barrier Reef officially starts north of Fraser, because reefs cannot thrive where there is a high amount of sediment in the water. The highlands are formed by indurated sand dunes, so in this case it is pretty clear that the ultimate origin of the island was by accumulation of generations of coastal dunes against some small basaltic hills during the Ice Age, when sea level was much lower than it is today. As sea level rose the sand dunes were isolated as an island, and the lowland behind them became the Sand Strait or Hervey Bay.

So the whole thing is formed by fine sand. Our vehicle was perfectly suited for this terrain, but any 2-wheel drive truck would have been hopelessly mired in the soft sand. We first crossed the island and came to the east coast, facing the Pacific, where we ran at 80 km per hour in the shallow water, along what Cook named the 75-mile beach. This is where we saw a dingo! This is the true, genetically pure, Australian wild dog. It somehow managed to get to the island 3,000 years ago, and from here it radiated into the Australian subcontinent, where it has now bred with all sorts of domestic dogs. But here, where there are no dogs, it remains genetically pure. Interestingly, they know it arrived about 3,000 years ago, because after that date it became a dominant motif in pictographic representations. They are wild and can be quite dangerous to kids and small adults, although on the surface they look like a skinny dog. They have been known to drown kangaroos by crowding on them along the beach; the kangaroo, which happens to be a good swimmer, goes in the water to get away from the dogs, but every time he tries to come back to the beach they attack, eventually the kangaroo gets tired, drowns, and gets eaten by the dingos (apparently a woman almost died the same way, but in the last minute was rescued by some fishermen).

Water is fascinating in the island, from the many springs formed as groundwater intersects the topography, to the perched dune crystalline lakes, which are fed exclusively by rainfall, and can go dry in times of drought (mean annual precipitation here is about 48 inches). The weird thing is that the lakes are in what looks like totally permeable sand, held perched only by the decaying vegetation that permeated through the sand. I forgot to mention that the island is covered by a luxuriant sub-tropical rainforest, with 100-foot trees and spiders with bodies the size of peanuts (plus platypus, equidnas, and kangaroos). So the question is, what do these tress feed on in an island formed by quartz sand? Minor vegetation apparently relies on fungi that grows between the sand grains, but the big trees rely on humic matter that has oozed down the sand grains to depths as great as 10 m. These sands are called coffee rocks, because they look like they have been permeated in thick coffee. In a million years the humic substances could very well crack into natural gas!

The springs are true oasis of luxuriant ferns, palms, and epiphytes. They are the closest I have ever seen to a Carboniferous landscape, including living fossils of Angiopteris evecta, a fern known from the Carboniferous.

I have so much more to tell you, but I am getting hungry and probably should stop here.  I saw another school of dolphins on the ferry trip back, and as we were driving back to town in the dusk we saw thousands of flying foxes (some truly enormous fruit-eating bats) leaving their roosts in the trees of the mainland to fly across the Sandy Strait and spend the night foraging in Fraser Island. What a day!

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