Australia

Description
Geochemical tomography sections based on mantle-derived pyrope garnet xenocrysts have been constructed for different tectonic domains along a southern transect crossing the Tasman Line. At the regional scale, these sections reveal thicker lithosphere and lower geothermal gradients with increasing tectonothermal age of the lithosphere domains. In a transect from the easternmostlocality (Jugiong) in Phanerozoic eastern Australia to the Eyre Peninsula (Gawler Craton) in Proterozoic South Australia, the palaeogeotherm decreases from greater than 50 mW/m₂ at Jugiong to around 40 mW/m₂ in South Australia and the depth to the lithosphere-asthenosphere boundary changes from -100 to 180 km. Geochemical tomography sections for the Gawler Craton region sampled in the Permian and theJurassic, indicate lithosphere thinning by about 10-15 km, attributed to the effect of Pangean rifting. These physical changes are paralleled by higher MgO and lower CaO and Al²O³ contents in progressively older lithospheric mantle, consistent with the global secular variation in mantle composition previously documented. Olivine is the most abundant mantle mineral in all sections and the Fe/Mg ratioof olivine is important in controlling the physical properties of lithospheric regions (density, Vp, Vs). Because olivine is rarely preserved, an inversion of the garnet-olivine Fe-Mg-exchange geothermometer has been used to calculate the Fe/Mg of olivine coexisting with each garnet grain. Application of this inversion to the southern Australian transect shows high Mg# (Mg/(Mg+Fe)) for olivine inthe shallow parts of the Proterozoic western sections and more Fe-rich olivine in the Phanerozoic eastern sections. There also is an overall trend to lower Mg# with increasing depth in each section, which may reflect infiltration by asthenospheric melts near the lithosphere-asthenosphere boundary. Olivine density varies inversely with Mg#, and the Proterozoic lithosphere in this traversetherefore is more buoyant, relative to the asthenosphere, than the Phanerozoic sections despite the lower geotherm beneath the craton. Vp and Vs vary directly with Mg# (the higher the Mg#, the higher the Vp and Vs) and thus these compositional differences are important in the interpretation of seismic tomography.
Biosphere Reserves in Australia
Australia currently has 14 Biosphere Reserves:
*Barkindji Biosphere Reserve, New South Wales
* Croajingolong National Park, Victoria
* Fitzgerald River National Park, Western Australia
* Great Sandy Biosphere Reserve, Queensland
* Hattah-Kulkyne National Park and Murray-Kulkyne Park, Victoria
* Kosciuszko National Park, New South Wales
* Mornington Peninsula and Western Port, Victoria
* Mamungari Conservation Park, SouthAustralia
(Previously "Unnamed Conservation Reserve")
* Noosa Biosphere Reserve, Queensland
* Prince Regent River Nature Reserve, Western Australia
* Riverland Biosphere Reserve, South Australia
* Calperum and Taylorville Stations
* Uluru - Kata Tjuta National Park, Northern Territory
* Wilsons Promontory National Park, Victoria
* Yathong Nature Reserve, NewSouth Wales
* Australia is a land like no other, with about one million different native species. More than 80 per cent of the country’s flowering plants, mammals, reptiles and frogs are unique to Australia, along with most of its freshwater fish and almost half of its birds.
* Australia’s marine environment is home to 4000 fish species, 1700 coral species, 50 types of marine mammal and a widerange of seabirds. Most marine species found in southern Australian waters occur nowhere else.
* Australia’s geographic isolation has meant that much of its flora and fauna is very different from species in other parts of the world. Most are found nowhere else. However, some closely related species are found on the continents which once made up the ancient southern supercontinent Gondwana....