Skeletal remains collected from 46 Bohemian and Moravian ossuaries were of an age corresponding to cold climatic fluctuations in the past millennium. It seems that climatic events, associated with limited solar activity, influenced the production of plant food. The values of δ¹⁵N and δ¹³C have a linera dependence, indicating a predominant sources of protenins. Simultaneously, the compositions of the bone collagen exhibited differences in the isotopic compositions of C and N, which could be caused by the better management in smaller municipalities and as a consequence of the availability of plant protenins with a higher content of the heavier isotopes of nitrogen or greater availability of animal proteins.

Smrčka V., Mihaljevič M. (2024): Depositing sskeletal remains in Czech and Moravian ossuaries and associated climatic variations. Radiocarbon 66, 552-567. (DOI)

For the first time, copper isotopes (expressed as δ⁶⁵Cu) wer used as indicators of reactions occurring during the Cu-ore heap leaching, an in situ technological process used for extraction of this strategic metal. In comparison with unleached ore (average δ⁶⁵Cu  -1.47‰), leached ores exhibit lighter isotopic values (average δ⁶⁵Cu -6.01‰) and enrichment of the leachate in heavier ⁶⁵Cu isotope indicating a dissolution of primary Cu-bearing minerals along with an oxidation process. Our results, based on combined measurements of Cu isotopes and mineralogical investigation with geochemical modelling, can be used as analogy of Cu leaching in gossans. 

Sracek O., Ettler V., Mihaljevič M., Kříbek B., Mapani B., Penížek V., Zádorová T., Vaněk A. (2024): Identification of processes in Cu-ore heap leaching using Cu isotopes and leachate chemistry at Tschudi mine, northern Namibia. Hydrometallurgy 228, 106356. (DOI)

Cobalt is one of the most important critical metals which could be potentially extracted from the old metallurgical slags in the Zambian Copperbelt. The slags from Luanshya, the oldest mining and smelting site in the Copperbelt, contain up to 5990 ppm Co (median: 2370 ppm). The detailed mineralogical investigation combined with the sulfuric acid leaching simulating hydrometallurgical recovery indicated that up to 67% of Co can be extracted from slag in a short period of time (24 h). However, despite the dramatic increase of Co prices on the global market, its recovery from the Luanshya slags appears to be non-economical due to the high costs of the mechanical and chemical processing of the slag materials. The paper is freely available via open access:

Ettler V., Mihaljevič M., Drahota P., Kříbek B., Nyambe I., Vaněk A., Penížek V., Sracek O., Natherová V. (2022): Cobalt-bearing copper slags from Luanshya (Zambian Copperbelt): Mineralogy, geochemistry, and potential recovery of critical metals. Journal of Geochemical Exploration 237, 106987. (DOI)

We compared analogous healthy topsoils and ones burned by fires of different temperatures for their elemental and isotopic Pb content. The fires only affected the top 5 cm of the soil. We found that soils affected by low-temperature fires had increased Pb compared to healthy soils. The accumulation of Pb was not observed in the soils exposed to higher temperatures. The same results were found in ash. Lead isotopic ratios were affected by the fires. These increased in soils affected by higher temperatures but didn’t change with the low temperatures. We proposed that the temperature dependence is due to anthropogenic Pb (²⁰⁶Pb/²⁰⁷Pb < 1.16) volatilizing at lower temperatures than geogenic Pb (²⁰⁶Pb/²⁰⁷Pb > 1.19). This work suggests that it may be possible to determine the temperature of a forest fire from the Pb isotopic signatures of the burned materials.

Baieta R., Vieira A.M.D, Vaňková M., Mihaljevič M. (2022): Effects of forest fires on soil lead elemental contents and isotopic ratios. Geoderma 414, 115760. (DOI)