Portable X-Ray Fluorescence and Gamma Ray Spectrometry exploration in the Serra da Neve Alkaline Complex, SW Angola
DOI:
https://doi.org/10.21701/bolgeomin/136.2/006Keywords:
Serra da Neve, portable instruments, REE (Nb-Ta), alkaline rocksAbstract
During PLANAGEO project, some areas were selected to undergo exploration programs according to target materials – Au (Fe); REE (Nb-Ta); Ni/Cr/Pt - using handheld field instruments. Portable instruments are widely used in exploration as a prompt way of obtaining information and direct field work and subsequent investigations. The Serra da Neve Alkaline Complex (SNAC) is a wide set of volcanic and subvolcanic structures that host REE (Nb-Ta)-bearing mineralogy. The same potential exists for elements with similar geochemical behavior such as incompatible trace elements, Large-Ion Lithophile Elements (LILE) and High-Field Strength Elements (HFSE), such as U and Th. The survey for a group of elements obtained by X-Ray Fluorescence and for equivalent Uranium (eU), equivalent Thorium (eTh) and Potassium by Gamma Ray Spectrometry showed similarities in their concentrations in rock sample sites. U and especially Th distribution show the same patterns as REE in different lithologies within the SNAC, mainly in the syenites. Nb tends to concentrate in alkaline dikes, apart from ijolites. There is a clear anomaly to be followed in the SE zone, in the Nejoio satellite intrusion.
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Banks, G., Walter, B., Marks, M., and Siegfried, P., 2019. A Workflow to Define, Map and Name a Carbonatite- or Alkaline Igneous-Associated REE-HFSE Mineral System: A Case Study from SW Germany. Minerals, 9 (2), 97. https://doi.org/10.3390/min9020097
Bau, M., and Dulsky, P., 1996. Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa. Precambrian Res., 79 (1996), pp. 37-55. https://doi.org/10.1016/0301-9268(95)00087-9
Borst, A., Finch, A., Nielson, G., Siegfried, P., Lopes, E., Eugenio, A., and Bambi, A. 2021 Alkaline magmatism and critical metals in Angola: Field observations and petrography of the Nejoio nepheline syenite complex. 7th International Geologica Belgica Meeting - Conference paper.
Chakhmouradian, A., and Wall, F., 2012. Rare Earth Elements: Minerals, Mines, Magnets (and More). Rare Earth Elements, Thematic Articles. Elements Magazine, October 2012. https://doi.org/10.2113/gselements.8.5.333
Comin-Chiaramonti, P., Barros Gomes, C., Cundari, Al., Castorina, F., and Censi, P., 2007. A review of carbonatitic magmatism in the Paraná-Angola-Namibia (PAN) system. Periodico di Mineralogia 76 (2-3), 25-78.
Do stal, J., 2017. Rare element deposits of alkaline igneous rocks. Resources, 6, 34. https://doi.org/10.3390/resources6030034
Fisher, L., Gazley, M., Baensch, A., Barnes, J., Cleverley, J., and Duclaux, G., 2014. Resolution of geochemical and lithostratigraphic complexity: a workflow for application of portable X-ray fluorescence to mineral exploration. Geochemistry: Exploration, Environment, Analysis. https://doi.org/10.1144/geochem2012-158
IAEA, 2003. Guidelines for radioelement mapping using gamma ray spectrometry. IAEA TECDOD 1363.
Liu, W., Li, Y., Wang, X., Cui, L., Zhao, Z., Liu, C., and Xu, Z., 2022. Weathering stage and topographic control on rare earth element (REE) behavior: New constraints from a deeply weathered granite hill, Chemical Geology, Volume 610, 121066,ISSN 0009-2541. https://doi.org/10.1016/j.chemgeo.2022.121066
Lopes, R., and Caessa, P, 2021. Geological Map of Angola 1:100 000, Sheet 295 - Capira and Sheet Report (1st edition). UTE (IGME, LNEG, Impulso) - IGEO, Luanda, 194p (in Portuguese).
Moyen, J-F., Cuney, M., Baratoux, D., Sardini, P., and Carrouée, S., 2021. Multi-scale spatial distribution of K, Th and U in an Archaean potassic granite: a case study from the Heerenveen batholith, Barberton Granite-Greenstone Terrain, South Africa. South African Journal of Geology, Vol 124. https://doi.org/10.25131/sajg.124.0005
Murakami, T., Ohnuki, T., Isobe, H., and Sato, T. 1997. Mobility of uranium during weathering. American Mineralogist 82 (9-10): 888-899. https://doi.org/10.2138/am-1997-9-1006
Pereira, E, and Moreira, A., 1978. Sobre o complexo de estruturas anelares da Serra da Neve (Angola). II Centenário Academia das Ciências, Lisboa. Estudos de Geologia, Paleontologia e Micologia, 97-120 (in Portuguese).
Prazeres, C., Batista, M. J., Lopes, R., Barros, B., Labaredas, J., Silva T. P., Albardeiro, L., and Plastov J. M,. 2023. Rare Earth Elements potential in the Serra da Neve Calc-alkaline Complex, SW Angola - a first approach. Colloquium of African Geology - Windhoek, Namibia. Book of Abstracts.
Ravansari, R., Wilson, S., and Tighe, M, 2019. Portable X-ray fluorescence for environmental assessment
Rodrigues, B., 1972. Conclusions on the distribution of alkaline and carbonatitic complexes of Angola and Brazil. Revista da Faculdade de Ciências, vol XVII-Fasc1º, 2ªsérie, Ciências Naturais, 89-108.
Rodrigues, B., 1973. Processos de fenitização relacionados com a estrutura anelar do Nejoio. PhD thesis, University of Luanda, Angola, 308p (in Portuguese).
Somarin, A., Zhou, L., and Steinhage, I., 2021. Application of handheld XRF on Ta-Nb-Sn-W ore: Factory calibration or user calibration? Geochemical Journal, Vol. 55, pp. 149-158. https://doi.org/10.2343/geochemj.2.0624
Shives, R., 2015. Using gamma ray spectrometry to find rare metals. In: Simandl, G. J. and Neetz, M. (Eds.). Symposium on strategic and critical materials proceedings, November 13-14, 2015, Victoria, British Columbia. British Columbia Geological
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