Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Melchiorre, E. B. Articles by Williams, P. A. Search for Related Content GeoRef GeoRef Citation

Stable Isotope Characterization of the Thermal Profile and Subsurface Biological Activity during Oxidation of the Great Australia Deposit, Cloncurry, Queensland, Australia

Erik B. Melchiorre

Geology and Geography Department, DePauw University, Greencastle, Indiana 46135

Peter A. Williams

University of Western Sydney, School of Science, Locked Bag 1797, Penrith South, New South Wales 1797, Australia

Corresponding author: e-mail, emelch{at}depauw.edu

The application of stable isotope thermometry and phase relations was used to examine the thermal evolution of oxidation and secondary mineralization at the Great Australia Cu-Au-Co deposit, Cloncurry, Queensland, Australia. Results show that early secondary mineralization consisted of djurleite crystallization at temperatures <93°C, followed by calcite mineralization at 66° to 75°C. The secondary mineralization paragenesis continued with azurite that formed at about 51°C, followed by malachite crystallization at 41° to 38°C, and malachite after azurite at 34°C. The final stage of secondary mineralization consists of calcite that formed at 25° to 30°C, followed by goethite. The general trend observed is for early oxidation and supergene enrichment at apparent temperatures less than 93°C and between 66° and 75°C, cooling to ambient surface temperatures late in the period of mineralization. A correlation is observed between decreasing isotope thermometry temperatures and increasing ¹³C values as oxidation and supergene enrichment progressed. This is interpreted to result from exothermic sulfide oxidation and associated subsurface thermophilic bacterial oxidation within the oxidation front. Over the period of oxidation and supergene enrichment, temperatures decreased and ¹³C values increased, recording in the secondary minerals the passing of the oxidation front and a diminishing subsurface bacterial carbon source.

This article has been cited by other articles:

				E. B. Melchiorre, P. A. Williams, T. P. Rose, and B. C. Talyn BIOGENIC NITROGEN FROM TERMITE MOUNDS AND THE ORIGIN OF GERHARDTITE AT THE GREAT AUSTRALIA MINE, CLONCURRY, QUEENSLAND, AUSTRALIA Can Mineral, December 1, 2006; 44(6): 1447 - 1455. [Abstract] [Full Text] [PDF]

				J. G. del Tanago, A. L. Iglesia, and A. Delgado Kamphaugite-(Y) from La Cabrera massif, Spain: a low-temperature hydrothermal Y-REE carbonate Mineralogical Magazine, August 1, 2006; 70(4): 397 - 404. [Abstract] [Full Text] [PDF]

				A. Rainbow, T. K. Kyser, and A. H. Clark Isotopic evidence for microbial activity during supergene oxidation of a high-sulfidation epithermal Au-Ag deposit Geology, April 1, 2006; 34(4): 269 - 272. [Abstract] [Full Text] [PDF]

				M. Boni, M. Boni, H. A. Gilg, G. Aversa, and G. Balassone The "Calamine" of Southwest Sardinia: Geology, Mineralogy, and Stable Isotope Geochemistry of Supergene Zn Mineralization Economic Geology, June 1, 2003; 98(4): 731 - 748. [Abstract] [Full Text] [PDF]

				E. B. Melchiorre and M. S. Enders Stable Isotope Geochemistry of Copper Carbonates at the Northwest Extension Deposit, Morenci District, Arizona: Implications for Conditions of Supergene Oxidation and Related Mineralization Economic Geology, May 1, 2003; 98(3): 607 - 621. [Abstract] [Full Text] [PDF]