PIXE analysis of skarn ore fluids Bismark, Mexico
Baker, T., van Achterbergh, E., Ryan, C.G., and Lang, J.R. (2003) PIXE analysis of skarn ore fluids Bismark, Mexico. In: Proceedings of the Seventh Biennial SGA Meeting on Mineral Exploration and Sustainable Development (1), pp. 227-230. From: Seventh Biennial SGA Meeting on Mineral Exploration and Sustainable Development, 24-28 August 2003, Athens, Greece.
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Metal budgets in porphyry copper deposit have been widely investigated in recent years through microanalysis (e.g. laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and proton-induced x-ray emission (PIXE)) of fluid inclusions. To date, however, there has been little application of such research to skarn systems. The Bismark deposit is a fault controlled, Zn-rich, stock-contact skarn deposit with early gamet-pyroxene alteration overprinted by massive sulfide (sphalerite-galena). Fluid inclusion studies reveal that pre-ore skarn formed from high temperature (> 400 0c), immiscible magmatic brine (type 3 inclusions) and vapor (type 2 inclusions) under lithostatic conditions (- 450 bars, 1.5 km depth). Subsequent movement on the Bismark fault induced major changes in pressure « 150 bars) that resulted in entrapment of lower temperature (400 to 100°C), moderate to low salinity magmatic fluids (critical to liquid-rich type IC and l A/B inclusions. PIXE analysis of the early brine and vapor fluid inclusions contain high Zn (0.3 and 0.] wt % respectively) and Pb (0.3 and 03 wI. % respectively), The later fluid inclusions contain lower Zn and Pb concentrations « 750ppm). Copper concentrations are highest in the early immiscible vapor-rich inclusions (- 400 ppm), but low overall compared to Zn and Pb (<200ppm in all other inclusion types). Ore precipitation occurred from a combination of pressure, temperature and salinity decrease and wall-rock reaction.
|Item Type:||Conference Item (Refereed Research Paper - E1)|
|Keywords:||skarn; fluid inclusions; PIXE; base metals|
|Date Deposited:||23 Jun 2010 04:02|
|FoR Codes:||04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 100%|
|SEO Codes:||84 MINERAL RESOURCES (excl. Energy Resources) > 8499 Other Mineral Resources (excl. Energy Resources) > 849999 Mineral Resources (excl. Energy Resources) not elsewhere classified @ 100%|
|Citation Count from Web of Science||