HR: 1340h
AN: V13E-0586    [Abstracts]
TI: Sulfide Metamorphism in Blueschist and Eclogite, North-Eastern New Caledonia
AU: * Brown, J L
EM: julie@ems.anu.edu.au
AF: Department of Earth and Marine Sciences, Australian National University, Building 47, Daley Rd., Canberra, ACT 0200 Australia
AU: Ellis, D J
EM: david.ellis@anu.edu.au
AF: Department of Earth and Marine Sciences, Australian National University, Building 47, Daley Rd., Canberra, ACT 0200 Australia
AU: Arculus, R
EM: richard.arculus@anu.edu.au
AF: Department of Earth and Marine Sciences, Australian National University, Building 47, Daley Rd., Canberra, ACT 0200 Australia
AU: Christy, A
EM: andrew.christy@anu.edu.au
AF: Department of Earth and Marine Sciences, Australian National University, Building 47, Daley Rd., Canberra, ACT 0200 Australia
AB: Knowledge of sulfide order-disorder transformations and chemical unmixing is central to understanding sulfide petrography. The prograde metamorphism of sulfide minerals is examined in blueschist and eclogite, part of a subduction complex in northern New Caledonia. Sulfide minerals equilibrate an order of magnitude faster than silicate minerals (Barton, 1970). During retrogression, sulfide structure and composition is not only susceptible to rapid changes induced by cooling but also by fluids, whose influx in New Caledonia has been facilitated along greenschist facies shear zones. It is likely that most matrix sulfide minerals exposed to these fluids would have re-equilibrated. However, sulfide minerals that became isolated from the matrix as inclusions in prograde porphyroblasts have been effectively armored against external changes in sulfur fugacity and have not been subject to changes induced by retrogression or fluid influx. Yet, it is likely that some such inclusions underwent isochemical unmixing. This paper will present results of ongoing study of sulfide metamorphism from northern New Caledonia. Barton P. B. (1970) Sulfide Petrology. Mineralogical Society of America, Reviews in Mineralogy 1, 11p.
DE: 3600 MINERALOGY AND PETROLOGY
DE: 3612 Reactions and phase equilibria (1012, 8412)
DE: 3613 Subduction zone processes (1031, 3060, 8170, 8413)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005