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Jonsson, Erik
Publications (10 of 61) Show all publications
Andersson, S. S., Wagner, T., Jonsson, E., Fusswinkel, T. & Whitehouse, M. J. (2019). Apatite as a tracer of the source, chemistry and evolution of ore-forming fluids: The case of the Olserum-Djupedal REE-phosphate mineralisation, SE Sweden. Geochimica et Cosmochimica Acta, 255, 163-187
Open this publication in new window or tab >>Apatite as a tracer of the source, chemistry and evolution of ore-forming fluids: The case of the Olserum-Djupedal REE-phosphate mineralisation, SE Sweden
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2019 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 255, p. 163-187Article in journal (Refereed) Published
Abstract [en]

This study explores the suitability of apatite as a tracer of the source(s), chemistry, and evolution of ore-forming hydrothermal fluids. This is tested by analysing the halogen (F, Cl, Br, and I), stable Cl isotopic, and trace element compositions of fluorapatite from the regional-scale Olserum-Djupedal rare earth element (REE) phosphate mineralisation in SE Sweden, which is dominated by monazite-(Ce), xenotime-(Y), and fluorapatite. The primary hydrothermal fluid flow system is recorded in a sequence from proximal granite-hosted to distal metasediment-hosted fluorapatite. Along this sequence, primary fluorapatite shows a gradual increase of Cl and Br concentrations and in (Gd/Yb)(N), a decrease of F and I concentrations, a decrease in delta Cl-37 values, in (La/Sm)(N), and partly in (La/Yb)(N) and (Y/Ho)(N). Local compositional differences of halogen and trace element concentrations have developed along rims and in domains adjacent to fractures of fluorapatite due to late-stage partial reaction with fracture fluids. These differences are insignificant compared to the larger deposit-scale zoning. This suggests that apatite can retain the primary record of the original ore-forming fluid despite later overprinting fluid events. The agreement between Br/Cl and I/Cl ratios of apatite and those of co-existing fluid inclusions at lower temperatures indicates that only a minor fractionation of Br from I occurs during apatite precipitation. The halogen ratios of apatite can thus be used as a first-order estimate for the composition of the ore-forming fluid. Taking the small fractionation factors for Cl isotopes between apatite and co-existing fluid at high temperatures into account, we propose that the Cl isotopic composition of apatite and the halogen ratios derived from the apatite composition can be used jointly to trace the source(s) of ore-forming fluids. By contrast, most trace elements incorporated in apatite are affected by the host rock environment and by fluid-mineral partitioning due to growth competition between co-crystallising minerals. Collectively, apatite is sensitive to changing fluid compositions, yet it is also able to record the character of primary ore-forming fluids. Thus, apatite is suitable for tracing the origin, chemistry, and evolution of fluids in hydrothermal ore-forming settings.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Olserum, REE, Apatite, Fluid tracer, Halogens, Stable Cl isotopes
National Category
Geology Geochemistry
Identifiers
urn:nbn:se:uu:diva-385956 (URN)10.1016/j.gca.2019.04.014 (DOI)000468170500009 ()
Funder
The Geological Survey of Sweden (SGU)Academy of Finland, 280458
Available from: 2019-06-19 Created: 2019-06-19 Last updated: 2019-06-19Bibliographically approved
Troll, V. R., Weis, F. A., Jonsson, E., Andersson, U. B., Majidi, S. A., Högdahl, K., . . . Nilsson, K. P. (2019). Global Fe-O isotope correlation reveals magmatic origin of Kiruna-type apatite-iron-oxide ores. Nature Communications, 10, Article ID 1712.
Open this publication in new window or tab >>Global Fe-O isotope correlation reveals magmatic origin of Kiruna-type apatite-iron-oxide ores
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2019 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 1712Article in journal (Refereed) Published
Abstract [en]

Kiruna-type apatite-iron-oxide ores are key iron sources for modern industry, yet their origin remains controversial. Diverse ore-forming processes have been discussed, comprising lowtemperature hydrothermal processes versus a high-temperature origin from magma or magmatic fluids. We present an extensive set of new and combined iron and oxygen isotope data from magnetite of Kiruna-type ores from Sweden, Chile and Iran, and compare them with new global reference data from layered intrusions, active volcanic provinces, and established low-temperature and hydrothermal iron ores. We show that approximately 80% of the magnetite from the investigated Kiruna-type ores exhibit d56Fe and d18O ratios that overlap with the volcanic and plutonic reference materials (> 800 degrees C), whereas similar to 20%, mainly vein-hosted and disseminated magnetite, match the low-temperature reference samples (<= 400 degrees C). Thus, Kiruna-type ores are dominantly magmatic in origin, but may contain latestage hydrothermal magnetite populations that can locally overprint primary hightemperature magmatic signatures.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-382552 (URN)10.1038/s41467-019-09244-4 (DOI)000464338100023 ()30979878 (PubMedID)
Funder
Swedish Research Council
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-05-10Bibliographically approved
Jonsson, E. & Högdahl, K. (2019). On the occurrence of gallium and germanium in the Bergslagen ore province, Sweden. GFF, 141(1), 48-53
Open this publication in new window or tab >>On the occurrence of gallium and germanium in the Bergslagen ore province, Sweden
2019 (English)In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 141, no 1, p. 48-53Article in journal (Refereed) Published
Abstract [en]

The presence of the critical and sought-after (semi-)metals gallium (Ga) and germanium (Ge) has previously been reported from mineralisations in the Bergslagen ore province, south central Sweden. Some of these reports were however recently shown to be questionable or erroneous. Here we summarise early analytical work on these metals in mineral deposits of the Bergslagen province, as well as briefly report new analytical data for Ga and Ge from recent, in part on-going work on different mineralisation types. The new data show that the sampled sulphide and iron oxide mineralisations in the Bergslagen province are overall not particularly enriched in Ga, and even less so with regards to Ge. One major exception is the significant Ga enrichment observed in skarn-hosted Fe-REE(-polymetallic) deposits of Bastnas type. Notably, these mineralisations also host increased contents of Ge. Based on this broader suite of sampled deposits, the suggested correlation between Ga and Al contents in previously studied material with relatively increased Ga grades, is in part contradicted, indicating that Ga is only in part sequestered through straightforward Al-substitution into aluminium silicate and oxide minerals. The mineralisations that do exhibit significantly increased Ge contents, in addition to the Bastnas-type deposits, are represented by both sulphide-dominated ones and Fe (-Mn) oxide-rich systems.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2019
Keywords
Gallium, germanium, Bergslagen, mineralisation, Sweden
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-385583 (URN)10.1080/11035897.2018.1525619 (DOI)000467182600004 ()
Funder
Swedish Research Council
Available from: 2019-06-17 Created: 2019-06-17 Last updated: 2019-06-17Bibliographically approved
Bowles, J. F. W., Cook, N. J., Sundblad, K., Jonsson, E., Deady, E. & Hughes, H. S. R. (2018). Critical-metal mineralogy and ore genesis: contributions from the European Mineralogical Conference held in Rimini, September 2016. Mineralogical magazine, 82, S1-S4
Open this publication in new window or tab >>Critical-metal mineralogy and ore genesis: contributions from the European Mineralogical Conference held in Rimini, September 2016
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2018 (English)In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 82, p. S1-S4Article in journal, Editorial material (Other academic) Published
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-366841 (URN)10.1180/minmag.2017.081.110 (DOI)000435650000001 ()
Funder
The Geological Survey of Sweden (SGU)
Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2018-12-03Bibliographically approved
Skoda, R., Plasil, J., Copjakova, R., Novak, M., Jonsson, E., Galiova, M. V. & Holtstam, D. (2018). Gadolinite-(Nd), a new member of the gadolinite supergroup from Fe-REE deposits of Bastnäs-type, Sweden. Mineralogical magazine, 82(Suppl. 1), S133-S145
Open this publication in new window or tab >>Gadolinite-(Nd), a new member of the gadolinite supergroup from Fe-REE deposits of Bastnäs-type, Sweden
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2018 (English)In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 82, no Suppl. 1, p. S133-S145Article in journal (Refereed) Published
Abstract [en]

A new member of the gadolinite supergroup, gadolinite-(Nd), IMA2016-013, ideally Nd2FeBe2Si2O10, was found in the Malmkarra mine, similar to 3.5km WSW of Norberg, south-central Sweden, where it occurs in association with fluorbritholite-(Ce), vastmanlandite-(Ce), dollaseite-(Ce), bastnasite-(Ce) and tremolite. Gadolinite-(Nd) forms anhedral grains up to 150 mu m in size, commonly occurring as aggregates of olive green colour. The crystals are transparent with vitreous to adamantine lustre. Gadolinite-(Nd) is brittle with conchoidal fracture, no cleavage or parting was observed. It has a white streak, the Mohs hardness is 6.5-7 and the calculated density is 4.86gcm(-3). Optically, the mineral is weakly pleochroic in shades of olive green, biaxial (-), n=1.78(1), n((calc.))=1.80, n=1.81(1) measured in white light, 2V((meas.))=62(3)degrees. Electron-microprobe and laser ablation inductively coupled plasma mass spectrometry analysis [in wt.%] provided SiO2 21.77, Y2O3 5.49, La2O3 2.78, Ce-2 O-3 14.04, Pr2O3 3.28, Nd2O3 19.27, Sm2O3 5.30, Eu2O3 0.24, Gd2O3 4.10, Tb2O3 0.36, Dy2O3 1.32, Ho2O3 0.18, Er2O3 0.38, MgO 0.51, CaO 0.14, MnO 0.10, FeO 10.62, B2O3 0.10, BeOcalc. 8.99, H2Ocalc. 0.55 and total 99.52 giving the following empirical formula (based on 2 Si): (Nd0.632Ce0.472Y0.268Sm0.168Gd0.125Pr0.110La0.094Dy0.039Ca0.014Er0.011Tb0.011Eu0.008Ho0.008)(Sigma 1.957)(Fe0.816Mg0.070Mn0.008)(Sigma 0.894)(Be1.984B0.016)(Sigma 2.000)Si2O9.660OH0.337. A weak Raman vibration band at similar to 3525cm(-1) confirms the presence of water in the structure. Gadolinite-(Nd) is monoclinic, P2(1)/c, with a=4.8216(3) angstrom, b=7.6985(4) angstrom, c=10.1362(6) angstrom, beta =90.234(4)degrees, V=376.24(6) angstrom(3) and Z=2. The strongest X-ray diffraction lines are [d(obs) in angstrom (hkl) I-rel]: 4.830 (100) 72, 3.603 (021) 37, 3.191(-112) 52, 3.097 (013) 35, 2.888 (121) 100, 2.607(113) 49, 2.412 (200) 24. Along with the Malmkarra mine, gadolinite-(Nd) was also recorded also at Johannagruvan and Nya Bastnas. The minerals of the gadolinite subgroup together with fluorbritholite-(Ce) incorporate the highest fraction of medium-to-heavy rare-earth elements among associated rare-earth element minerals in the Malmkarra mine and possibly in all Bastnas-type deposits.

Place, publisher, year, edition, pages
MINERALOGICAL SOC, 2018
Keywords
gadolinite-(Nd), rare-earth elements, new mineral, crystal structure, Malmkarra, Bastnas-type deposits
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-359667 (URN)10.1180/minmag.2017.081.047 (DOI)000435650000007 ()
Funder
Swedish Research CouncilThe Geological Survey of Sweden (SGU)
Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-09-05Bibliographically approved
Siidra, O. I., Jonsson, E., Chukanov, N. V., Nekrasova, D. O., Pekov, I. V., Depmeier, W., . . . Yapaskurt, V. O. (2018). Grootfonteinite, Pb3O(CO3)(2), a new mineral species from the Kombat Mine, Namibia, merotypically related to hydrocerussite. European journal of mineralogy, 30(2), 383-391
Open this publication in new window or tab >>Grootfonteinite, Pb3O(CO3)(2), a new mineral species from the Kombat Mine, Namibia, merotypically related to hydrocerussite
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2018 (English)In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 30, no 2, p. 383-391Article in journal (Refereed) Published
Abstract [en]

Grootfonteinite, Pb3O(CO3)(2), is a new Pb oxycarbonate found in a mineralogically complex, banded assemblage from the Mn (-Fe) oxide ore unit of the Kombat mine. Grootfonteinite is named after the locality in the Grootfontein district. The mineral forms platy grains up to 1 mm across and up to 0.2 mm thick included in and intergrown with massive cerussite. Grootfonteinite is colourless, with white streak and adamantine lustre. It is brittle with perfect cleavage on (0 0 1). The density calculated using the empirical formula H0.345Na0.275Ca0.045Pb2.645C2O7 is 6.856 g.cm(-3). The strongest five reflections in the X-ray powder-diffraction pattern [(d in angstrom)-(Intensity)-(hkl)] are: 4.586-25-0 1 0, 3.244-100-0 1 3, 2.652-30-1 1 0, 2.294-21-0 2 0, 2.053-39-0 2 3. Grootfonteinite crystallizes in space group P6(3)/mmc (No. 194), a = 5.303(1), c = 13.770(3) angstrom, v= 335.3(1) angstrom(3), Z= 2. The crystal structure of grootfonteinite is formed by layered blocks which consist of sheets with composition [PbCO3] and (ideally) [PbO], the stacking of which can be described as center dot center dot center dot-[PbCO3]-[PbO]-[PbCO3]-center dot center dot center dot The composition of the resulting electroneutral 2D block is {[Pb-2(CO3)(2)][(Pb0.7Na0.3)(O-0.7(OH)(0.3))]}(0). The stereochemically active 6S(2) lone electron pairs of the two Pb atoms are located in between the blocks, resembling the classical case of the structure of litharge. Grootfonteinite is structurally related to hydrocerussite, abellaite, and plumbonacrite. A characteristic structural feature of all these minerals is the presence of [PbCO3](0) sheets in the upper and lower parts of invariably electroneutral 2D blocks, the middle part being variable. The topology of 2D blocks in the crystal structure of grootfonteinite can be considered as intermediate between those of abellaite and hydrocerussite. These three minerals can be considered to form a merotype family. Other members of this family can be hypothesized which differ in the nature of the interleaved sheets.

Place, publisher, year, edition, pages
E SCHWEIZERBARTSCHE VERLAGSBUCHHANDLUNG, 2018
Keywords
grootfonteinite, carbonate, lead, hydrocerussite, abellaite, layered structure, new mineral, Kombat mine
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-365842 (URN)10.1127/ejm/2018/0030-2723 (DOI)000444631000018 ()
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2018-11-27Bibliographically approved
Grew, E. S., Jonsson, E. & Langhof, J. (2018). Lithium-200 Years: Symposium and Field Trip June 14-16, 2018. Elements, 14(4), 284-284
Open this publication in new window or tab >>Lithium-200 Years: Symposium and Field Trip June 14-16, 2018
2018 (English)In: Elements, ISSN 1811-5209, E-ISSN 1811-5217, Vol. 14, no 4, p. 284-284Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
Mineralogical Society of America, 2018
National Category
Climate Research
Identifiers
urn:nbn:se:uu:diva-370055 (URN)10.2138/gselements.14.4.284 (DOI)000448617200009 ()
Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2018-12-20Bibliographically approved
Andersson, S. S., Wagner, T., Jonsson, E. & Michallik, R. M. (2018). Mineralogy, paragenesis, and mineral chemistry of REEs in the Olserum-Djupedal REE-phosphate mineralization, SE Sweden. American Mineralogist, 103(1), 125-142
Open this publication in new window or tab >>Mineralogy, paragenesis, and mineral chemistry of REEs in the Olserum-Djupedal REE-phosphate mineralization, SE Sweden
2018 (English)In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 103, no 1, p. 125-142Article in journal (Refereed) Published
Abstract [en]

The rapidly growing use of rare earth elements and yttrium (REE) in modern-day technologies, not least within the fields of green and carbon-free energy applications, requires exploitation of new REE deposits and deposit types. In this perspective, it is vital to develop a fundamental understanding of the behavior of REE in natural hydrothermal systems and the formation of hydrothermal REE deposits. In this study, we establish a mineralogical, textural, and mineral-chemical framework for a new type of deposit, the hydrothermal Olserum-Djupedal REE-phosphate mineralization in SE Sweden. An early, high-temperature REE stage is characterized by abundant monazite-(Ce) and xenotime-(Y) coexisting with fluorapatite and subordinate amounts of (Y,REE,U,Fe)-(Nb,Ta) oxides. During a subsequent stage, allanite-(Ce) and ferriallanite-(Ce) formed locally, partly resulting from the breakdown of primary monazite-(Ce). Alteration of allanite-(Ce) or ferriallanite-(Ce) to bastnasite-(Ce) and minor synchysite-(Ce) at lower temperatures represents the latest stage of REE mineral formation. The paragenetic sequence and mineral chemistry of the allanites record an increase in Ca content in the fluid. We suggest that this local increase in Ca, in conjunction with changes in oxidation state, were the key factors controlling the stability of monazite-(Ce) in the assemblages of the Olserum-Djupedal deposit. We interpret the alteration and replacement of primary monazite-(Ce), xenotime-(Y), fluorapatite, and minor (Y,REE,U,Fe)-(Nb, Ta) oxide phase(s), to be the consequence of coupled dissolution-reprecipitation processes. These processes mobilized REE,Th,U, and Nb-Ta, which caused the formation of secondary monazite-(Ce), xenotime-(Y), fluorapatite, and minor amounts of allanite-(Ce) and ferriallanite-(Ce). In addition, these alteration processes produced uraninite, thorite, columbite-(Fe), and uncharacterized (Th,U,Y,Ca)-silicates. Textural relations show that the dissolution-reprecipitation processes affecting fluorapatite preceded those affecting monazite-(Ce), xenotime-(Y), and the (Y, REE, U, Fe)-(Nb, Ta) oxide phase(s). The mineralogy of the primary ore mineralization and the subsequently formed alteration assemblages demonstrate the combined mobility of REE and HFSE in a natural F-bearing high-temperature hydrothermal system. The observed coprecipitation of monazite-(Ce), xenotime-(Y), and fluorapatite during the primary REE mineralization stage highlights the need for further research on the potentially important role of the phosphate ligand in hydrothermal REE transporting systems.

Place, publisher, year, edition, pages
MINERALOGICAL SOC AMER, 2018
Keywords
Rare earth elements, hydrothermal, monazite, xenotime, allanite, apatite, Olserum, Sweden
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-348929 (URN)10.2138/am-2018-6202 (DOI)000426312800011 ()
Funder
Swedish Research CouncilThe Geological Survey of Sweden (SGU)Academy of Finland, 280458
Available from: 2018-04-25 Created: 2018-04-25 Last updated: 2018-04-25Bibliographically approved
Andersson, S. S., Wagner, T., Jonsson, E., Fusswinkel, T., Leijd, M. & Berg, J. T. (2018). Origin of the high-temperature Olserum-Djupedal REE-phosphate mineralisation, SE Sweden: A unique contact metamorphic-hydrothermal system. Ore Geology Reviews, 101, 740-764
Open this publication in new window or tab >>Origin of the high-temperature Olserum-Djupedal REE-phosphate mineralisation, SE Sweden: A unique contact metamorphic-hydrothermal system
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2018 (English)In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 101, p. 740-764Article in journal (Refereed) Published
Abstract [en]

The Swedish part of the Fennoscandian Shield hosts a variety of rare earth element (REE) deposits, including magmatic to magmatic-hydrothermal types. This paper focuses on the origin of the Olserum-Djupedal REEphosphate mineralisation located in the sparsely studied Vastervik region, SE Sweden. Here, mineralisation occurs in three main areas, Olserum, Djupedal and Bersummen. Primary hydrothermal REE mineralisation formed at high temperatures (about 600 degrees C), leading to precipitation of monazite-(Ce), xenotime-(Y), fluor apatite and minor (Y,REE,U,Fe)-(Nb,Ta)-oxides in veins and vein zones dominated by biotite, amphibole, magnetite and quartz. The veins are hosted primarily by metasedimentary rocks present close to, or within, the contact aureole of a local 1.8 Ga ferroan alkali feldspar granite pluton, but also occur within in the chemically most primitive granite in the outermost part of that pluton. In the Djupedal area, REE-mineralised metasedimentary bodies are extensively migmatised, with migmatisation post-dating the main stage of mineralisation. In the Olserum and Bersummen areas, the REE-bearing veins are cross-cut by abundant pegmatitic to granitic dykes. The field-relationships demonstrate a-protracted magmatic evolution of the granitic,pluton and a clear spatial and temporal relationship of the REE mineralisation to the granite. The major and trace element chemistry of ore-associated biotite and magnetite support genetic links between all mineralised areas. Biotite mineral chemistry data further demonstrate a distinct chemical trend from meta sediment-hosted ore-associated biotite distal to the major contact of the granite to the biotite in the granite hosted veins. This trend is characterised by a systematic decrease in Mg and Na and a coupled increase in Fe and Ti with proximity to the granite-hosted veins. The halogen compositions of ore-associated biotite indicate elevated contents of HCl and HF in the primary REE mineralising fluid. Calculated log(f(HF)/f(HCL)) values in the Olserum area suggest a constant ratio of about -1 at temperatures of 650-550 degrees C during the evolution of the primary hydrothermal system. In the Djupedal and Bersummen areas, the fluid locally equilibrated at lower log (f(HF)/f(HCl)) values down to -2. High Na contents in ore-associated biotite and amphibole, and the abundance of primary ore-associated biotite indicate a K- and Na-rich character of the primary REE mineralising fluid and suggest initial high-temperature K-Na metasomatism. With subsequent cooling of the system, the fluid evolved locally to more Ca-rich compositions as indicated by the presence of the Ca-rich minerals allanite-(Ce) and uvitic tourmaline and by the significant calcic alteration of monazite-(Ce). The later Ca-rich stages were probably coeval with low to medium-high temperature (200-500 degrees C) Na-Ca metasomatism variably affecting the granite and the wall rocks, producing distinct white quartz-plagioclase rocks. All observations and data lead us to discard the prevailing model that the REE mineralisation in the Olserum-Djupedal district represents assimilated and remobilised former heavy mineral-rich beds. Instead, we propose that the primary REE mineralisation formed by granite-derived fluids enriched in REE and P that were expelled early during the evolution of a local granitic pluton. The REE mineralisation developed primarily in the contact aureole of this granite and represents the product of a high temperature contact metamorphic-hydrothermal mineralising system. The REE mineralisation probably formed synchronously with K-Na and subsequent Na-Ca metasomatism affecting the granite and the wall rocks. The later Na-Ca metasomatic stage is probably related to a regional Na +/- Ca metasomatic and associated U +/- REE mineralising system operating concurrently with granitic magmatism at c. 1.8 Ga in the Vastervik region. This highlights the potential for discovering hitherto unknown REE deposits and for the reappraisal of already known deposits in this part of the Fennoscandian Shield.

Keywords
Olserum, Djupedal, REE, Phosphate, Metasomatism, Halogen fugacity
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-369766 (URN)10.1016/j.oregeorev.2018.08.018 (DOI)000448092400040 ()
Funder
Swedish Research Council
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2018-12-17Bibliographically approved
Chukanov, N. V., Jonsson, E., Aksenov, S. M., Britvin, S. N., Rastsvetaeva, R. K., Belakovskiy, D. I. & Van, K. V. (2017). Roymillerite, Pb24Mg9(Si9AlO28)(SiO4)(BO3)(CO3)10(OH)14O4, a new mineral: mineralogical characterization and crystal chemistry. Physics and chemistry of minerals, 44(10), 685-699
Open this publication in new window or tab >>Roymillerite, Pb24Mg9(Si9AlO28)(SiO4)(BO3)(CO3)10(OH)14O4, a new mineral: mineralogical characterization and crystal chemistry
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2017 (English)In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 44, no 10, p. 685-699Article in journal (Refereed) Published
Abstract [en]

The new mineral roymillerite Pb24Mg9(Si9AlO28)(SiO4)(BO3)(CO3)(10)(OH)(14)O-4, related to britvinite and molybdophyllite, was discovered in a Pb-rich assemblage from the Kombat Mine, Grootfontein district, Otjozondjupa region, Namibia, which includes also jacobsite, cerussite, hausmannite, sahlinite, rhodochrosite, barite, grootfonteinite, Mn-Fe oxides, and melanotekite. Roymillerite forms platy single-crystal grains up to 1.5 mm across and up to 0.3 mm thick. The new mineral is transparent, colorless to light pink, with a strong vitreous lustre. Cleavage is perfect on (001). Density calculated using the empirical formula is equal to 5.973 g/cm(3). Roymillerite is optically biaxial, negative, alpha = 1.86(1), beta ae gamma = 1.94(1), 2V (meas.) = 5(5)A degrees. The IR spectrum shows the presence of britvinite-type tetrahedral sheets, , , and OH- groups. The chemical composition is (wt%; electron microprobe, H2O and CO2 determined by gas chromatography, the content of B2O3 derived from structural data): MgO 4.93, MnO 1.24, FeO 0.95, PbO 75.38, B2O3 0.50, Al2O3 0.74, CO2 5.83, SiO2 7.90, H2O 1.8, total 99.27. The empirical formula based on 83 O atoms pfu (i.e. Z = 1) is Pb24.12Mg8.74Mn1.25Fe0.94B1.03Al1.04C9.46Si9.39H14.27O83. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is triclinic, space group P , with a = 9.315(1), b = 9.316(1), c = 26.463(4) , alpha = 83.295(3)A degrees, beta = 83.308(3)A degrees, gamma = 60.023(2)A degrees, V = 1971.2(6) (3). The crystal structure of roymillerite is based built by alternating pyrophyllite-type TOT-modules Mg-9(OH)(8)[(Si,Al)(10)O-28] and I-blocks Pb-24(OH)(6)O-4(CO3)(10)(BO3,SiO4). The strongest lines of the powder X-ray diffraction pattern [d, (I, %) (hkl)] are: 25.9 (100) (001), 13.1 (11) (002), 3.480 (12) (017, 107, -115, 1-15), 3.378 (14) (126, 216), 3.282 (16) (-2-15, -1-25), 3.185 (12) (-116, 1-16), 2.684 (16) (031, 301, 030, 300, 332, -109, 0-19, 1-18), 2.382 (11) (0.0.-11). Roymillerite is named to honor Dr. Roy McG. Miller for his important contributions to the knowledge of the geology of Namibia.

Keywords
New mineral, Roymillerite, Britvinite, Crystal structure, IR spectroscopy, Kombat Mine, Namibia
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-340914 (URN)10.1007/s00269-017-0893-2 (DOI)000414161200001 ()
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-02-23Bibliographically approved
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