The Great Australia/Pacific Adventure: 29. Hobart, Tasmania

Wednesday-Thursday, 21-22 NOV 2012

Departing Burnie, we sailed east and then south along the eastern side of Tasmania, then back west to Hobart, which is on the southeast side of Tasmania at latitude 42.9 S, essentially the same latitude south as Lansing, MI is north, and thus close to the same latitude as our hometown of Midland, MI. That's also about the same latitude as Christchurch, New Zealand.

Just to the east of Hobart we passed Cape Raoul, a pointe on the Tasman Peninsula, with its spectacular cliffs of columnar dolerite. Time for a geology lesson. Magma cools to form characteristic polygonal columns, mostly hexagons and pentagons, a hundred feet long or more, when it is injected underground at relatively shallow depths, as in a sill or dike or plug. This formation is thus intrusive, not extrusive - - i.e. it's not volcanic. Dolerite has the same composition as basalt (the kind of lava in Hawai'i, in the mid-ocean ridge and the deep seafloor) and a medium-size crystal grain. The size of the component mineral crystals is larger than in extrusive (volcanic) basalt because it cooled more slowly, remaining covered by layers of earlier rocks into which it intruded. The crystals are smaller than gabbro or granite because the intruded magma cooled more quickly than a deep batholith that is typically injected several kilometers below the surface. As the magma cools it shrinks and breaks up into polygonal patterns the same way as red clay mud flats do in the sun.

Here's the famous bridge across the Derwent river. It's famous partly because in the '70s a large ore boat rammed into a couple of the supports toward one end, collapsing a section of the bridge, sinking the ship, and dumping a few hapless automobiles in the river, killing a few people both on the ship and on the bridge. It also isolated one side of the city (the side with the airport) from the other side (the business district) for two years. A local manufacturer of small ferry boats responded immediately and innovatively to meet the sudden need, and is now the world's leading manufacturer of large catamaran ferry boats.

Of course we visited the Royal Tasmanian Botanical Gardens.

All we need is some cheese to go with this, and we can have cheese and quackers:

We took a long coach ride up to the top of Mt Wellington, where we encountered spectacular views, Chinese tourists, cold howling winds, and a dusting of snow.

The next day we took another long coach ride to the Tahune Forest Air Walk, an extensive elevated walkway through the canopy of a temperate rainforest. It was raining most of the time, so our photography was limited.