ABSTRACT

The intensities of cathodoluminescence (CL) in calcite -- nonluminescent, dull, luminescent -- are believed to reflect the relative concentrations of Mn and Fe, an activator and a quencher of luminescence, respectively. Such interpretation leads to a common perception that the luminescence of cements and the redox state of the diagenetic environment are directly related. To test these propositions, pure CL zones in meteoric and burial calcite cements from the Sverdrup Basin were visually identified and their Fe, Mn, Mg, and Ca contents were measured by Secondary Ion Mass Spectrometry (SIMS). Factor analysis of these data confirmed that CL intensity, Mn, and Fe load on a common factor, but the positive loading of Mn and the negative one of Fe are weak. Three domains emerge clearly in the Fe-Mn space. All spots with more than 1000 to 1500 ppm Fe are dull. Below this threshold, points with more than 225 ppm Mn are luminescent. The third domain, with lesser Mn and Fe contents, can display any of the above listed CL intensities. This shows that the Fe-Mn pair alone cannot explain the luminescence zones in calcite.

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