Intro: With so much diverse and abundant national parks, nature and geology to see in Tasmania, it was only a matter of time before a long bushwalk was required (bushwalking is what Australians commonly call ‘hiking’ here…)
Over 45% of the state of Tasmania is recognized as a national park, there is much to choose from, but a particular quartzite capped mountain beckoned an ascent. Thus, I headed out with a couple of friends to summit the 1443 m Frenchman’s Cap, located in the Franklin-Gordon Wild Rivers National Park.
The hike is a 3-5 days return trek with two huts along the way at Lake Vera and Lake Tahune providing shelter, however, full camping tents and equipment is require. We did the trip in 4 days, with several side scurries along the mountains. The track itself weaves in and out through temperate rain forests, boggy low lands, high alpine terrain, and steep mountainous rocky cliffs.
But the climb is well worth it, for once at the top you not only get gorgeous 360° views of the wild western Tasmania, but (particularly for me) you get to check out and admire the spectacular folds and composition of the rocks making up this impressive peak. More geological detail is required? Why, I’d thought you’d never ask…
Science Spheel: Un Chapeau Blanc (Geology, Geomorphology)
Unlike the common Tasmanian dolerite rock type that makes up almost all of the highest peaks in Tasmania, Frenchman’s cap has a distinctive quartzite cap. Its story goes back to the oldest known geological period in Tasmania, the Precambrian (approximately 700 million year ago).
At this point Tasmania was part of a shallow sea where mud, silt and sand accumulated on the seafloor. With time, temperature and pressure (both confining from above and mountain building), these sediments were metamorphosed and folded in phyllites, mica/garnetiferous-mica/dolomitic/quartz schists, and quartzite (Spry, 1963).
Quartzite specifically is both tough and dense, and therefore resistant to erosion. Because of this, the quartzite and quartz schists cap the main peak and ridges of Frenchmans. The valleys are made of mostly schistose and phyllitic rocks, but their morphology and the spectacular shape of the mountains owe their glory to the ancient thrust faulting and folding, and the less ancient (but still 35,000 to 10,000 years ago) glaciations that carved the land. The shape of Frenchman’s Cap “chapeau blanc” appearance is mostly a product of the last glaciation period, where the partial horn making the cap was cut and sculpted into on several sides by cirque glaciers (Peterson, 1966).
Final Thoughts: Walking through this Western Tasmanian Wilderness World Heritage Area, I can’t help but be surprised that here, or even the state of Tasmania in general, is part of Australia. When you look at the diverse foliage and temperate rain forests of the Franklin-Gordon Wild Rivers National Park in the west it is clear that it definitely isn’t the stereotypical Australian outback.
Tasmania has some of the best bushwalking in Australia, and the 1443 m white quartzite dome of Frenchman’s Cap is a challenging summit, but immensely rewarding bushwalk through the pristine, wild Tasmanian wilderness. The geology alone is reason enough for me, but combined with the foliage, fauna, landscape and trekking experience, this walk in the wild is one not to be forgotten, and it will leave you itching for more…
Until next time, cheers!
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