Log of Tasmania Field Course
June 14:
June 14th saw us back on the road again toward the beauty of the National Park of Markoopa Caves and the Mole Creek Valley.
Fig. 37: Katie and Mike stand at the entrance to Marakoopa Caves which held many awesome speleothems (solution formations) but also the unforgettable scene of glow worms working their fluorescent magic near the large cavern entrance, clearly an example of life in extreme environments.
Fig 38: The vast cave system in the Mole Creek region is formed within an Ordovician Limestone unit (the Gordon Limestone). It is a warm water limestone that alternates within a quartz sandstone sequence, typical for many cratons during the Cambro-Ordovician periods of the early Paleozoic. Here Sam B. sits atop an actual fossil of giant snail (Helmut shell) that prowled the coral and bryozoan reefs of the Ordovician seas in Tasmania. Anyone for escargot?
Fig. 40: No one was prepared for the awesome beauty of the beginnings of the Great Western Tiers that we saw along the cloud line as we entered the Mole Creek Valley. This is the crown of the Gondwana stratigraphy, that same Jurassic dolerite that faced us off at Mt Wellington had come back to great us as we neared the end of our road trip.
June 15:
Brought us up at an early hour to drive the last 150 kms of our road trip. But first we needed to see remarkable gorge the Great Central Plateau, and the wildlife at Brighton.
Fig. 41. The Alum Cliffs near Mole Creek are in the Gog Range a folded sequence of Ordovician quartzites which are here cut into a deep chasm by the Mersey River. The local is an important Aboriginal site and had served as a ceremonial gathering place (Corrombora) for millennia, we could easily see why.
Fig 42. Our ascent of the Central Plateau included the spectacular climb up the A-4 highway near Liffey Falls. Here Andrew, Sally, and Julia provide an emotional expression of what lay before them. Dolerite, dolerite, and more dolerite.
Fig 43. The higher elevations on the southern and eastern faces of the Western Tiers are overgrown with the large gum trees at lower elevations (tree ferns and Swamp Gums) but here near the top it’s the Snow Gum that comes back just before the top rim.
Fig. 44. A small stream drains the snow fields that rim the elevated ridge of the Central Plateau, if this were sagebrush instead of dwarf myrtle and stunted pine; the landscape might resemble the high plains of North America. Parts of this landscape and biota are included in the United Nations World Heritage Site designation.
Fig. 47: The devil himself met our group at the Brighton animal park. Here we learned of the dire fate of the devil as it faces extinction due to a devastating viral tumor disease called Facial Tumor Disease. There are attempts to isolate healthy populations on offshore islands as the disease takes its toll across the island, then perhaps a program of reintroduction. But in the mean time feral predators such as foxes and cats are rapidly filling the ecological niches left behind as the Tasmanian Devil population dwindles. This is an ecological catastrophe taking place before our eyes.
