Stable Isotope Evidence for the Origin of the Jurassic MN Carbonate Ore of Eplény, Transdanubian Central Range, Hungary (original) (raw)
A manganese carbonate ore sample from Eplény, Transdanubian Central Range, Hungary, consists of Mn calcite and Ca rhodochrosite, with moderate quartz. The Mn and Fe contents of the ore are 7.51% and 0.86%, respectively, giving an Mn/Fe ratio of 8.73. The δ13CPDB of that sample is -2.20‰, which indicates that the carbon was derived from seawater or from the dissolution of carbonate precipitated from seawater. The δ18OPDB is -0.25‰, indicating a low-temperature origin. The Eplény ore differs from the Úrkút Mn-carbonate ore in mineral, chemical, and C isotopic contents. While Úrkút Mn-carbonate mineralization occurred as the result of bacterial oxidation of organic matter coupled with Mn-oxide reduction in the early diagenetic zone of sulfate reduction, the Eplény ore was likely synsedimentary or very early diagenetic precipitation from seawater, perhaps mediated of microbial activity.
Related papers
Rhodochrosite-bearing concretions from a Jurassic Manganese ore mineralization – Úrkút, Hungary
2013
Rhodochrosite concretions with fish and plant fossils occur in the Urkut manganese carbonate deposit (Jurassic) and were investigated for mineralogy and geochemistry. These concretions are mainly composed of rhodochrosite and Mn-bearing calcite, but X-ray diffraction and electron microprobe analysis showed also the presence of Ca-rich kutnohorite. Cathodoluminescence microscopy revealed kutnohorite as luminescent mineral as infiltration and veinlets suggesting early diagenetic origin. Chrysotile needles were also detected in one of the kutnohorite veinlets by transmission electron microscopy. Stable C and O isotope results showed low-T very early diagenetic, bacterially mediated decomposition of organic matter and formation of Mn-carbonate in the ore section, which effect was the strongest around the organic remnants. Compared to the polarized light microscopy, cathodoluminescence microscopy was able to give visible picture about the texture of the very fine-grained Mn-carbonate con...
Rhodocrosite-bearing concretions from a Jurassic manganese ore mineralization - Úrkút, Hungary
Carpathian Journal of Earth and Environmental Sciences, 2013
Rhodochrosite concretions with fish and plant fossils occur in the Úrkút manganese carbonate deposit (Jurassic) and were investigated for mineralogy and geochemistry. These concretions are mainly composed of rhodochrosite and Mn-bearing calcite, but X-ray diffraction and electron microprobe analysis showed also the presence of Ca-rich kutnohorite. Cathodoluminescence microscopy revealed kutnohorite as luminescent mineral as infiltration and veinlets suggesting early diagenetic origin. Chrysotile needles were also detected in one of the kutnohorite veinlets by transmission electron microscopy. Stable C and O isotope results showed low-T very early diagenetic, bacterially mediated decomposition of organic matter and formation of Mn-carbonate in the ore section, which effect was the strongest around the organic remnants. Compared to the polarized light microscopy, cathodoluminescence microscopy was able to give visible picture about the texture of the very fine-grained Mn-carbonate concretions; therefore it was proved to be a useful method in study of diagenetic processes in manganese deposits.
2015
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.