Three Compositional Varieties of Rare-Earth Element Ore: Eudialyte-Group Minerals from the Norra Kärr Alkaline Complex, Southern Sweden

AbstractMoskvinite-(Y), Na2K(Y,REE)Si6O15, is a rare mineral, which until now has only been described from its type locality Dara-i-Pioz, Tajikistan. At Ilímaussaq moskvinite-(Y) was discovered in a drill core from Kvanefjeld, where it occurs as a replacement mineral associated with a mineral belonging to the britholite group. The composition was determined by a combination of electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry analyses. The empirical formula based on 15 oxygens is Na1.94K0.99(Y0.94Yb0.03Er0.03Dy0.03Ho0.01Gd0.01)∑1.05Si5.98O15. The coexistence of an almost pure Y and a light rare-earth element (REE) mineral is interpreted as fractionation ofREEand Y during the replacement of an earlier formedREEmineral. Theoretical calculations of the observed replacement of feldspathoids by natrolite show that the generated fluid would have pH > 8, which inhibits large scale mobility ofREE. In addition, a K-Fe sulfide member of the chlorbartonite-bartonite group is for the first time observed in Ilímaussaq where it occurs where sodalite is replaced by natrolite and arfvedsonite by aegirine. The sulfide incorporates the S and some of the Cl generated by the alteration of sodalite, whereas the K and Fe originates from the replacement of arfvedsonite by aegirine.

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Rare earth element geochemistry of the Fen alkaline complex, Norway

Contributions to Mineralogy and Petrology ◽

10.1007/bf00401455 ◽

1975 ◽

Vol 52 (4) ◽

pp. 247-259 ◽

Cited By ~ 55

Author(s):

Roger H. Mitchell ◽

Arild O. Brunfelt

Keyword(s):

Rare Earth ◽

Rare Earth Element ◽

Earth Element ◽

Alkaline Complex ◽

Element Geochemistry

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Crystallization and destabilization of eudialyte-group minerals in peralkaline granite and pegmatite: a case study from the Ambohimirahavavy complex, Madagascar

Mineralogical Magazine ◽

10.1180/minmag.2017.081.053 ◽

2018 ◽

Vol 82 (2) ◽

pp. 375-399 ◽

Cited By ~ 5

Author(s):

Guillaume Estrade ◽

Stefano Salvi ◽

Didier Béziat

Keyword(s):

Rare Earth ◽

Rare Earth Element ◽

Earth Element ◽

Parental Magma ◽

Accessory Minerals ◽

Eudialyte Group ◽

Peralkaline Granite ◽

Rich Material ◽

Highly Evolved

AbstractEudialyte-group minerals (EGM) are very common in highly evolved SiO2-undersaturated syenites and are characteristic minerals of agpaitic rocks. Conversely, they are extremely rare in peralkaline granites, with only a handful of EGM occurrences reported worldwide. Here, we study two new examples of EGM occurrence in two types of peralkaline pegmatitic granites from the Cenozoic Ambohimirahavavy complex, and assess the magmatic conditions required to crystallize EGM in peralkaline SiO2-oversaturated rocks. In the transitional granite (contains EGM as accessory minerals) EGM occur as late phases and are the only agpaitic and major rare-earth element (REE) bearing minerals. In the agpaitic granite (contains EGM as rock-forming minerals) EGM are early-magmatic phases occurring together with two other agpaitic minerals, nacareniobsite-(Ce) and turkestanite. In these granites, EGM are partly-to-completely altered and replaced by secondary assemblages consisting of zircon and quartz in the transitional granite and an unidentified Ca-Na zirconosilicate in the agpaitic granite. Ambohimirahavavy EGM, as well as those from other peralkaline granites and pegmatites, are richer in REE and poorer in Ca than EGM in nepheline syenites. We infer that magmatic EGM are rare in SiO2-oversaturated rocks because of low Cl concentrations in these melts. At Ambohimirahavavy, contamination of the parental magma of the agpaitic granite with Ca-rich material increased the solubility of Cl in the melt promoting EGM crystallization. In both granite types, EGM were destabilized by the late exsolution of a fluid and by interaction with an external Ca-bearing fluid.

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Timing and source of rare earth element mineralisation in the Ditrău alkaline complex, Romania

Applied Earth Science ◽

10.1080/03717453.2017.1306293 ◽

2017 ◽

Vol 126 (2) ◽

pp. 93-93

Author(s):

Richard Shaw ◽

Kathryn Goodenough ◽

Nick Roberts ◽

Victoria Honour ◽

Matt Horstwood ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Element ◽

Earth Element ◽

Alkaline Complex

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Constraining the Conditions of Rare Earth Element Mineralization in the Bear Lodge Alkaline Complex, Wyoming: A Fluid Inclusion Study

10.46427/gold2020.1991 ◽

2020 ◽

Author(s):

Danielle Olinger ◽

Allen Andersen ◽

Mitchell Bennett

Keyword(s):

Rare Earth ◽

Fluid Inclusion ◽

Rare Earth Element ◽

Earth Element ◽

Fluid Inclusion Study ◽

Alkaline Complex ◽

Inclusion Study

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Magmatic origin and petrogenesis characterization of syenite rock from Pakkanadu alkaline complex, Southern Granulite Terrain, India: Implication on emplacement and petrogenetic history

Journal of Applied and Natural Science ◽

10.31018/jans.v13i4.2919 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1214-1224

Author(s):

P. Gangatharan ◽

K. Anbarasu ◽

M. Satyanarayanan

Keyword(s):

Rare Earth ◽

Rare Earth Element ◽

Tamil Nadu ◽

Earth Element ◽

Alkaline Complex ◽

Carbonatite Complex ◽

Study Region ◽

Magmatic Origin ◽

South Indian ◽

Granulite Terrain

The present study mainly focused on understanding the magmatic origin and petrogenesis characterization based on the Petrography, major, trace and Rare Earth Element (REE) signatures in the alkaline syenite from Pakkanadu alkaline carbonatite complex. The alkaline plutons from South Indian granulite terrain are intruded along with Archaean epidote-hornblende gneisses. The study area was carbonatite complexes of Tamil Nadu and is characterized by a group of rock associations Carbonatite-Syenite-Pyroxenite - Dunite. From Harker various patterns Pakkanadu alkaline complex syenite showed increasing trends of SiO2, Al2O3, Na2O + K2O opposite to decreasing order of CaO, Fe2O3, MgO, TiO2, P2O5 and MnO trend, suggest fractionation of clinopyroxene, hornblende, sphene, apatite and oxide minerals and feldspar that ruled the fractionation. The concentration of trace elements enriched in Large Ion lithophile elements (LILE) (Ba, Sr, and Rb) elements and High Field Strength Elements (HFSEs) indicated that the dyke intrusion by differentiation of magma from a mantle source. Rare earth element (REE) distribution of Light rare earth element (LREE) enriched and High rare earth element (HREE) depleted pattern show strongly fractionated pattern with moderate Eu anomalies. Plots of tectonic discrimination diagrams of Pakkanadu samples fall in the field of syn-COLG field to the VAG syn- COLG field. For the first time, this type of study was carried out in the study region in a detailed manner. The present study significantly exposed the petrography, petrogenesis and magmatic origin process in the Pakkanadu alkaline carbonatite complex.

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