Zinc-Manganese Carbonates from Broken Hill, New South Wales

W. D. Birch
Department of Mineralogy and Petrology, Museum of Victoria, 285-321 Russell Street, Melbourne, Victoria 3000, Australia

Abstract: Specimens of honey-brown to pinkish-brown globular carbonates encrusting concretionary goethitecoronadite from the oxidized zone at Broken Hill, New South Wales, have compositions in the rhodochrositesmithsonite series. This may be the first extensive natural occurrence of this solid-solution series. Growth of the carbonates occurred in zones which have near uniform composition. The ratio MnCO3/(MnCO3 + ZnCO3) for each zone bears a linear relationship to the measured d spacing for the 101¯4 X-ray reflections. Because cerussite is the only other mineral associated with the Zn-Mn carbonates and because of an absence of detailed locality information, the paragenetic significance of these minerals cannot be determined. The solutions depositing them may have been derived from the near-surface equivalents of the Zinc Lode horizons.

Keywords: carbonates • rhodochrosite • smithsonite • Broken Hill • New South Wales • Australia

Mineralogical Magazine; March 1986 v. 50; no. 355; p. 49-53; DOI: 10.1180/minmag.1986.050.355.07
© 1986, The Mineralogical Society
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