Congratulations to Noemi Vicentini on her HiTech AlkCarb thesis (2017) Noemi Vicentini at Universita’ degli Studi “G. D’Annunzio” Chieti—Pescara has recently completed a fifth-year thesis on A new carbonatite classification: nomenclature and taxonomy. Geochemical analyses were supported by HiTech AlkCarb and the project was supervised by Francesco Stoppa and Jindrich Kynicky. Thanks are given to Mariangela Shiazza, Francesco Ambrosio and Gianluigi Rosatelli for their support. Project partners can download a copy of thesis to read from the dropbox. Abstract: The carbonatites were classified by different authors through the last decades (e.g. Woolley 1989), but today archaic nomenclature is still in use. The USGS criteria for the classification of igneous rocks affirm the primary classification should be based on the mineral content or mode. If a mineral is impossible to determinate then other criteria can be used, like chemical composition. In this study I propose a carbonatites classification, in particular the fluorcarbonatites will be chemically described because, until now, in literature the term “fluorcarbonatite” hasn’t a concrete definition. I collected all the carbonatites data from Georock database, and I selected the analysis which contain information on the fluorine content. To chemically discretize the fluorcarbonatites from other carbonatites types I used the RHA language created by Petrov and Moskin (2000), through the Rank formulas I was able to extrapolate the samples in which fluorine is more important than the other elements. The fluorine is present in the common parental magma of all carbonatites, but it is not present or barely present in the carbonatite rocks. This problem can be easily solved; the fluorine is a volatile in the parental magma, so some chemical reactions are needed to fix the fluorine in a mineral, otherwise the fluorine disappears. The fluorine is present in a variety of minerals like bastnaesite, pyrochlore, fluorite and fluorapatite and these minerals form in different stages of the carbonatite development. So, it’s possible to find fluorine in almost every stage (from orthomagmatic to hydrothermal). All carbonatite types show great enrichment in Eu, Ba, Sr, Y and U (positive anomalies); and there are negative anomalies of Eu, Zr, Ti, Th, Rb, Cs, Pb and K. The isotopic data were analyzed, but only few samples have isotopic analysis (more than 400 sample don’t have isotopic information). It seems that the source of these carbonatites is in the asthenospheric mantle, possibly related to the plume activity, but, due to the lack of information on almost the entire database, it’s not possible to extend this theory to all the carbonatites. Further news from Universita’ degli Studi “G. D’Annunzio” Chieti—Pescara Since the last newsletter, Ud’A have discovered two new carbonatite occurrences in the Roman Region associated with large calderas. Until recently, carbonatites in Italy have seemed restricted to only the monogenic igneous activity within small grabens in the Appennines, and the only known example of carbonatite activity in a composite volcano was Mt. Vulture. We are gathering mineral and geochemical data of the new occurrences and will soon submit a paper. Pianciano carbothermal rocks have been studied in detail and a geological model of their formation has been submitted to an international magazine. Look out for these new publications soon!
Recent publications Chakhmouradian, A.R., Reguir, E. Zaitsev, N., Couëslan, C., Xu, C., Kynicky, J., Mumin, H., and Yang , P. 2017. Apatite in carbonatitic rocks: Compositional variation, zoning, element partitioning and petrogenetic significance, Lithos, 274, 188-213. 10.1016/j.lithos.2016.12.037 Chen, H. Cheng, X., Zheng,, Z., Kynicky, J., Song, W.S., and Wang, L. 2017. Petrogenesis and mineralization of REE-rich granites in Qingxi and Guanxi, Nanling region, South China. Ore Geology Reviews, 81, 1, 309-325, 10.1016/j.oregeorev.2016.10.021 Elliott, H.A.L., Wall, F., Chakhmouradian, A.R., Siegfried, P.R., Dahlgren, S., Weatherley, S., Finch, A.A., Marks, M.A.W., Dowman, E., Deady, E. 2018. Fenites associated with carbonatite complexes: A review. Ore Geology Reviews, 93, 38-59. https://doi.org/10.1016/j.oregeorev.2017.12.003 Goodenough, K.M., Wall, F., and Merriman, D. 2017. The Rare Earth Elements: Demand, Global Resources, and Challenges for Resourcing Future Generations, Natural Resources Research, 27, 2, 201–216 Hurai, V., Paquette, J-L., Huraiová, M., Slobodník, M., Hvožďara, P., Siegfried, P.R., Gajdošová, M., and Milovská, S. 2017. New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions. Ore Geology Reviews, 80, 1072–1091. https://doi.org/10.1016/j.oregeorev.2016.09.017 Hutchison, W. Mather, T.A., Pyle, D.M., Boyce, A.J., Gleeson, M.L.M., Yirgue, G., Blundy, J.D., Ferguson, D.J., Vye-Brown, C., Millar, I.L., Sims, K.W.W., and Finch, A.A. 2018. The evolution of magma during continental rifting: New constraints from the isotopic and trace element signatures of silicic magmas from Ethiopian volcanoes. Earth and Planetary Science Letters, 489, 203-218. https://doi.org/10.1016/ j.epsl.2018.02.027 Isakova, A.T., Panina, L.I., Stoppa , F. 2017. Genesis of kalsilite melilitite at Cupaello, Central Italy: Evidence from melt inclusions, Petrology, 25, 4, 433–447 https://link.springer.com/article/10.1134/ S0869591117040038 Kynicky, J., Smith, M.P., Song, W., Chakhmouradian, A.R. and Brtnicky, M. in press. The role of carbonatefluoride melt immiscibility in shallow REE deposit evolution, Geoscience Frontiers, xxx, 1-12. https:// doi.org/10.1016/j.gsf.2018.02.005 Marks, M.A.W. and Markl, G. 2017. A global review on agpaitic rocks , Earth-Science Reviews. 173, 229-258. https://doi.org/10.1016/j.earscirev.2017.06.002 Smith, M.P., Kynicky, J., Xu, C., Song, W., Spratt, J., Jeffries, T., Brtnicky, M., Koprivabe, A., Cangelosif, D. 2018. The origin of secondary heavy rare earth element enrichment in carbonatites: Constraints from the evolution of the Huanglongpu district, China, Lithos, 308-309, 65-82. https://doi.org/10.1016/ j.lithos.2018.02.027 Song, W., Cheng, X., Chakhmouradian, A.R., Kynicky, J., Huang, K., and Zhang, Z.. 2017. Carbonatites of Tarim (NW China): First evidence of crustal contribution in carbonatites from a large igneous province. Lithos, 282, 1-9. 10.1016/j.lithos.2017.02.018 Xu, C., Kynicky, J., Smith, M.P., Kopriva, A., Brtnický, M., Urubek, T., Yang, Y., Zhao, Z., He, C., and Song, W.. 2017. Origin of heavy rare earth mineralisation in South China. Nature Communications, 8, 1–7. doi:10.1038/ncomms14598