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Thorite, Thorogummite and Xenotime-(Y) Occurrence in Ditrau Alkaline Intrusive Massif, East Carpathians, Romania

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THE PUBLISHING HOUSE GEONOMY OF THE ROMANIAN ACADEMY Research article THORITE, THOROGUMMITE AND XENOTIME-(Y) OCCURRENCE IN DITRAU ALKALINE INTRUSIVE MASSIF, EAST CARPATHIANS, ROMANIA PAULINA HIRTOPANU 1* , GYULA JAKAB 2, C. JENS ANDERSEN 3 and J. ROBERT FAIRHURST 3 1 Department of Mineralogy, University of Bucharest, Romania 2 IG Mineral Gheorgheni, Romania 3 University of Exeter, Camborne School of Mine, UK Corresponding author : *[email protected] Received July 10, 2013 The thorite and thorogummite, closely associated with the xenotime-(Y) represent the characteristic paragenessis of the Belcina type mineralization of the Ditrau alkaline intrusive massif. The Belcina vein mineralization is localized in the South-East of the massif, within the Cambrian metamorphic Tulghes Group. Genetically the Belcina mineralization is linked to the red alkaline syenites, the fluid responsible for the mineralisation belonging to the late-stage hydrothermal event. Late stage calcite, siderite, ferrodolomite veins and development of the Fe-oxides and hydroxides (hematite, goethite, lepidocrocite), minor sulphides of Fe, Pb, Zn, Mo and Hg, may be present. Also, REE-apatite, monazite-(Nd), monazite-(Ce), brabantite, ferrocolumbite, manganocolumbite, Nb-rutile, zircon, magnetite, thorianite, Y-fluorite are present as primary mineralization sequence. The gangue associated to the ore is represented by feldspars (microcline, albite, orthoclase), quartz, different common carbonates of at least two generations, natrolite, pectolite and different chlorites. Electron microprobe analyses of many individual grains of thorite gave mainly ThO 2=70-80.00, SiO 2=15- 17.00, ZrO=0-6, FeO=0-4% and very little Ce 2O3, UO 2, Y 2O3, PbO and P 2O5 contents. Thorogummite has less ThO 2, more SiO 2, ZrO, FeO, CaO, PbO and P2O5, than thorite. Thorite and especially thorogummite have an oscillatory chemical composition. The xenotime-(Y) has a constant composition, with of about Y2O3=60-62 and P 2O5=38-40% (wt). Because of so many common carbonates, as mineral gangue, the Belcina Th-Y mineralization could be attributed to a carbothermal process more than to a hydrothermal one. Key words: thorite, thorogummite, xenotime-(Y), Nb-rutile, monazite-(Ce), brabantite, apatite, ferrocolumbite, zircon, natrolite, pectolite, Fe oxides/hydroxides, hydrothermal/carbothermal activity. INTRODUCTION/GEOLOGICAL affiliation to anorogenic alkaline magmas explains SETTING 1 their general feature Nb>>Ta and the predominance of LREE in the first mineralization The Ditrau alkaline intrusive complex is stages and the Th-Y one in the last hydrothermal situated within the Cambrian metamorphic Tulghes /carbothermal stages. The Ditrau alkaline intrusive Group of the inner part of the East Carpathians. It complex represents the end of a long lasting has a distinct ring structure (Streckeisen, 1960), fractionation processes in the crust and deep upper having a succession of magmatic events from mantle, respectively. This explains the modest gabbroic and dioritic magma to syenitic and dimensions of Ditrau intrusion and its enrichment various postmagmatic events as well, developed with incompatible elements. The high petrographic between a Triassic extensional stage and a Jurassic complexity of Ditrau massif is doubled by a great rifting stage (Krautner & Bindea, 1996). The diversity of mineral occurrences. In addition to the succession of the magmatic events in Ditrau, could 85 minerals, previously mentioned (Jakab, 1998, be completed with carbonatite intrusion that Constantinescu, 1999), about 200 were recently followed the alkaline intrusion and used the same identified, many of them being first occurrences in pathways as the previous alkaline silicate melt. Its Romania (Hirtopanu et al. , 2003, Hirtopanu et al. , Proc. Rom. Acad., Series B, 2013 , 15( 2), p. 111–131 112 Paulina Hirtopanu et al. 2010a, 2010b). The rare element minerals determined Ditrau massif (SE), in the surrounding metamorphic in Ditrau complex intrusion, belong to the following rocks of the Tulghes Group, at 2.5 km distance of 6 classes (in the predominant order): REE(Y) – massif (Jakab, 1998) (Fig. 1). The Belcina occurrence Carbonates; Nb, Ta, REE(Y), Ti, Zr, Th, U –Oxides; comprises a complex mineralization, different from REE(Y) –Phosphates; REE(Y), Th, Zr, Pb –Silicates; that reported in Jolotca. It is mostly constituted of Th Halides and Tellurides (Hirtopanu et al., 2010b). silicates and Y-phosphates, less zircon, niobian rutile, They occur in a small mineralization areas (Lazarea, ferrocolumbite, Y-fluorite, less sulphides, and almost Hereb-Cianod, Ditrau Valley/ Pricske, Aurora, Putna, no Nb-Ta pyrochlores (which occur frequently in Creanga Halasag) and in two big vein mineralization Jolotca area), small/almost no REE(Y) – silicates areas, Jolotca and Belcina (Fig. 1). The biggest (allanite, which has a big development in Jolotca Jolotca occurrence from the NV of the massif is of area, chevkinite, etc), and small/no REE(Y)- vein type and comprises a complex sulphides carbonates (which also have a big development in mineralization. The rare elements mineralizations Jolotca area). Also, there are present as accessory/ followed after sulphides, almost all the rare element constituent primary minerals such as: Th-apatite, Fe- minerals being developed as veins in sulphides, as a oxides and hydroxides (magnetite, hematite, goethite, late hydrothermal phase. They are represented by lepidocrocite), some sulphides (pyrite, arsenopyrite, LREE-carbonates; Nb,Ta, REE(Y), Ti, Zr, Th, U galena, sphalerite, chalcopyrite, tetrahedrite, oxides; REE(Y), Th phosphates; REE(Y), Zr, Th, Ti, molybdenite, cinnabar) and native mercury Hg, in the REE silicates; Bi and Pb-Bi tellurides; and halides calcite-ferrodolomite-siderite and apatite gangue. The (Hirtopanu 2006, Hirtopanu et al ., 2010a, 2010b). samples studied here (around 50) were collected from The Jolotca rare elements mineralization has a the vein situated at the confluence of Belcina Valley gangue of ferrodolomite, ankerite, siderite and with Kisgyor Rivulet and were abbreviated with calcite. The other occurrence of vein type is the “Bel”. The samples collected from Jolotca were Belcina, less big than Jolotca, situated outside of the abbreviated with “Dt”. Fig. 1. The schematic geological map of Ditrau alkaline massif with mineralization areas : hornblendite-diorite complex (blue), red syenite (red), white nepheline syenite (yellow), Tulghes Group (grey), F = fault, G8 =crustal fracture (hachure interrupted line), (acc. to Jakab, Gyula). Thorite, thorogummite and xenotime-(y) occurrence in Ditrau alkaline intrusive massif, East Carpathians, Romania 113 MINERALOGY complete series. Also, thorite is related to a mineral called huttonite (ThSiO 4). Thorite and huttonite are The first and complete mineralogical description dimorphs. The two minerals have the same of Belcina mineralization belongs to Jakab (1982, chemistry, they just have different structures. 1998) who determined representative minerals of Huttonite is monoclinic and belongs to the following mineral classes: a. silicates: K feldspar, Monazite Group, being related structurally to its albite, chlorite, biotite, sericite, thorite, zircon, members. Also, there is a close related mineral epidote; b. oxides: ilmenorutile, rutile, anatas, thorogummite, that was once considered a variety columbite, pyrochlore, fersmite, magnetite, loparite, of thorite but it is a product of its hydrothermal ilmenite, hematite; c. phosphates: xenotime, apatite, alteration. Because thorite is highly radioactive, Y-fluorapatite; d. carbonates: calcite, ferrodolomite; specimens are often metamictized. This is a state sulphides: pyrite, arsenopyrite, galena, sphalerite, found in radioactive minerals and results from the chalcopyrite, tetrahedrite, molybdenite. The mineral destructive effects of their own radiation on their crystallization order (Jakab, 1998) is: Paragenesis I: crystal lattice. The effect can lead to destroying pegmatitic quartz-feldspar gangue; ferrodolomite+ completely its own crystal lattice while leaving the quartz; niobotantalates+xenotime+ thorite+fluorapa- external appearance unchanged. In the Belcina tite+arsenopyrite+sphalerite+molybdenite+pyrite+ chlo- area, thorite occurs as a constituent mineral, while rite; ferrodolomite; calcite+galena; Paragenesis the Jolotca thorite is an accessory mineral. The II:pyrite+sphalerite+galena+calcite+quartz. The K/Ar Belcina thorite occurs as irregular grains (Fig. 3) of microcline ages, shows for the Belcina mineralization a few mm and much longer up to 1cm in diameter. the same age as the Ditrau rocks (Jakab, 1998). Also, It could be massive and compact. The Jolotca the same author showed that the Jolotca thorite has idiomorph crystals with habits as square mineralization, having the predominance of Y in short prisms (Fig. 2), pseudooctahedral crystals. respect to Ce, and high Th content, belongs Macroscopically it is nearly opaque being genetically to the magmatic red syenites. The first transparent in thin fragments. In transmitted light it modern study of the Belcina occurrence was made in is yellow-orange, red, brownish yellow, brownish laboratories of CSM, Exeter University (2007–2009). black, black (Figs. 2 and 3). It has a distinct, poor After a minutely optical study, the samples were (110) cleavage (Fig. 2) and is uniaxial (+). The analyzed chemically by microprobe and SEM. The refringence (n ≈1.85), greater than that of the electron microprobe data, which
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  • Petrology and Mineralogy of the Mount Rosa Area, El Paso and Teller Counties, Colorado

    Petrology and Mineralogy of the Mount Rosa Area, El Paso and Teller Counties, Colorado

    THE AMERICAN MINERALOGIST, VOL. 5 1, MARCH-APRIL, 1966 PETROLOGY AND MINERALOGY OF THE MOUNT ROSA AREA, EL PASO AND TELLER COUNTIES, COLORADO. II. PEGMATITESI EuceNB B. Gnoss, CaliJornia Diris,ion of Mines and Geology San Fra nci sco, C alifor n i o AND E. Wu. IIerNnrcu, Department of Geologyand Mineralogy The Llniversity of Michigan, Ann Arbor, Michigan. Aesrnlcr Two contrasting swarms of pegmatite dikes occur intermingled in the Pikes Peak granite and in related alkalic granites in the Mount Rosa area, west of Colorado Springs. One is the older calc-alkalic Pikes Peak type; the younger is the alkalic Mount Rosa type. The accessory assemblage of the Mount Rosa quartz-microcline-riebeckite pegmatites consists chiefly of radioactive zircon, fluorite, astrophyllite, thorite, and lesser amounts of pyrochlore, rutile, niobian rutile, columbite, bertrandite and rare aluminofluorides. These dikes intrude both the Pikes Peak and its derivative fayaiite granites along north- east-trending fractures. These pegmatites contrast markedly with the coexisting Pikes Peak pegmatites, which are characterized by quartz and amazonite crystals, zircon, biotite, siderite, and minor topaz, allanite, cassiterite and genthelvite. The Pikes Peak type occurs as segregations and injected bodies only within Pikes Peak granite. Age determinations on zircons from pegmatites of the Mount Rosa type proved to be inconsistent, but ages determined by means of the Kao/Ara0 method on pegmatitic rie- beckite are consistent rvith geological evidence and age determinations on the granites, giving an age of 1040 my. INrnolucrroN Discoverl' of unusual minerals in pegmatitesof the St. Peters Dome district, Mount Rosa area,Colorado, attracted the attention of mineralo- gists as earlv as 1877 (Koenig, 1877).
  • Thermodynamics of Formation of Coffinite, Usio4

    Thermodynamics of Formation of Coffinite, Usio4

    Thermodynamics of formation of coffinite, USiO4 Xiaofeng Guoa,b, Stéphanie Szenknectc, Adel Mesbahc, Sabrina Labsd, Nicolas Clavierc, Christophe Poinssote, Sergey V. Ushakova, Hildegard Curtiusd, Dirk Bosbachd, Rodney C. Ewingf, Peter C. Burnsg, Nicolas Dacheuxc, and Alexandra Navrotskya,1 aPeter A. Rock Thermochemistry Laboratory and Nanomaterials in the Environment, Agriculture, and Technology Organized Research Unit, University of California, Davis, CA 95616; bEarth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545; cInstitut de Chimie Séparative de Marcoule, UMR 5257, CNRS/CEA/Université Montpellier/Ecole Nationale Supérieure de Chimie de Montpellier, Site de Marcoule, 30207 Bagnols sur Cèze, France; dInstitute of Energy and Climate Research, Nuclear Waste Management, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; eCEA, Nuclear Energy Division, RadioChemistry & Processes Department, BP 17171, 30207 Bagnols sur Cèze, France; fDepartment of Geological and Environmental Sciences, School of Earth Sciences, Stanford University, Stanford, CA 94305; and gDepartment of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 Contributed by Alexandra Navrotsky, April 20, 2015 (sent for review February 10, 2015) Coffinite, USiO4, is an important U(IV) mineral, but its thermody- The precipitation of USiO4 as a secondary phase should be namic properties are not well-constrained. In this work, two dif- favored in contact with silica-rich groundwater (21) [silica − ferent coffinite samples were synthesized under hydrothermal concentration >10 4 mol/L (22, 23)]. Natural coffinite samples conditions and purified from a mixture of products. The enthalpy are often fine-grained (4, 5, 8, 11, 13, 15, 24), due to the long of formation was obtained by high-temperature oxide melt solu- exposure to alpha-decay event irradiation (4, 6, 25, 26) and are tion calorimetry.
  • Runoff Potential of Mureş River Upper Basin Tributaries

    Runoff Potential of Mureş River Upper Basin Tributaries

    RUNOFF POTENTIAL OF MUREŞ RIVER UPPER BASIN TRIBUTARIES V. SOROCOVSCHI1, CS.HORVÁTH2 ABSTRACT. – Runoff Potential of Mureş River Upper Basin Tributaries. The upper basin of the Mureş River includes a significant area of the Eastern Carpathians central western part with different runoff formation conditions. In assessing the average annual runoff potential we used data from six gauging stations and made assessments on three distinct periods. Identifying the appropriate areas of the obtained correlations curves (between specific average runoff and catchments mean altitude) allowed the assessment of potential runoff at catchment level and on geographical units. The potential average runoff is also assessed on altitude intervals of the mentioned areas. The runoff potential analysis on hydrographic basins, geographical units and altitude intervals highlights the variant spatial distribution of this general water resources indicator in the different studied areas. Keywords: water resources, Mureş upper basin, geographic units, altitude intervals 1. GENERAL CONSIDERATIONS The upper basin of the Mureş River includes a significant area of the Eastern Carpathians central western part, also known as Moldavo-Transylvanian Carpathians (V. Mihăilescu, 1963). In the study area we find a large part of the Eastern Carpathians neoeruptive chain, represented by the southern slopes of Căliman Mountains, eastern and northern slopes of the Gurghiu Mountains and the northern extremity of the Harghita Mountains (Fig. 1). The runoff formation conditions in the vulcanic chain depend of the neoeruptive relief altitude, which is generally decreasing from north to south, and of the exposure to the advection of western moist air masses. The volcanic relief morphology (cones, craters and plateaus, less represented in the study area) influences only the direction of runoff.