Discussion two high‐grade schistosities at broken hill and their relation to minor structures: A reply

1976 ◽  
Vol 23 (4) ◽  
pp. 456-458
Author(s):  
R. W. R. Rutland ◽  
M. A. Etheridge
Keyword(s):  
High Grade ◽  
Broken Hill

Microstructural interpretation of some fibrolitic sillimanite aggregates

1975 ◽  
Vol 40 (311) ◽  
pp. 303-306 ◽  
Author(s):  
R. H. Vernon
Keyword(s):  
Low Energy ◽  
High Grade ◽  
Broken Hill ◽  
Metamorphic Assemblage ◽  
Small Grains

SummaryFibrolitic sillimanite in some high-grade gneisses from Broken Hill, Australia, shows microstructural features suggestive of compatibility with the main coarser-grained assemblage, namely: framework-silicate interfaces either meet (110)-sillimanite/framework-silicate interfaces at approximately 90° or are attached to the ends of 'fibrolite' rods; framework-silicate interfaces are deflected by 'fibrolite' grains; and interfaces of inclusions of one framework silicate in another are deflected by 'fibrolite' grains, producing irregular, rather than rounded, inclusion shapes. These criteria suggest that the 'fibrolite' in some rocks is a compatible member of the main metamorphic assemblage. Its persistence as small grains may be due to a high proportion of relatively low-energy prismatic boundaries in the fibrolitic aggregates.

Garnet-biotite relationships in high grade metamorphic rocks at Broken Hill, Australia

1976 ◽  
Vol 113 (3) ◽  
pp. 263-270 ◽  
Author(s):  
I. R. Plimer
Keyword(s):  
Wall Rock ◽  
Metamorphic Grade ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Broken Hill

SummaryGarnets and biotites from pelitic, psammitic and quartzofeldspathic rock enclosing the Broken Hill orebodies are sensitive to syn and post high grade metamorphic metasomatism associated with orebody-wall rock reactions but the overall garnet—biotite partitioning relationships remain unchanged. KMg-FeDgarnet-biotite and metamorphic grade calculations increase from NW to SE over the 1000 m section examined which is in accord with the regional grade variation.

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