Danburite-bearing calc-silicate rocks from the Ascot Hills, Dookie, Victoria
Titel:
Danburite-bearing calc-silicate rocks from the Ascot Hills, Dookie, Victoria
Auteur:
Birch, W. D.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 43 (1996) nr. 4 pagina's 387-393
Jaar:
1996-08
Inhoud:
The rare calcium borosilicate danburite occurs with ferro-axinite, grossular-andradite, vesuvianite, tourmaline, chlorite, fluorite, quartz and calcite in a small exposure in the Ascot Hills, 8 km south-southwest of Dookie, in north central Victoria. The assemblage forms discontinuous bands and lenticular patches within metamorphosed fine-grained Cambrian greenstones of the northern Mt Wellington Belt, adjacent to the Dookie Fault. The minerals represent boron metasomatism superimposed on burial metamorphism to greenschist facies. The Dookie Fault acted as a channelway for the boron-rich solutions. The boron was probably remobilised from within the greenstone sequence, either from lavas which exchanged boron with seawater during emplacement, or from siliceous marine sediments, now cherts, interbedded with the volcanic rocks. Solution composition was probably the major influence in determining whether danburite or datolite crystallised. This occurrence is only the second record of danburite in Australia.
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