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1

Study on the mechanism of action of various metal ions on the surface of monazite

Liu Rongxiang, Yang Zhanfeng, Li Jie, Cao Zhao, Li Qiang, Li Jichuan

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 185901

EN

By studying the various metal ions released from the grinding process, and conducting the flotation test of monazite and symbiotic ore, using zeta potential measurements and FTIR infrared spectrum analysis methods, the influence of metal ions on the surface of monazite and the mechanism of action are obtained. The results showed that the main metal ions in the flotation environment of monazite are Ca2+, Ba2+, and Fe3+. When the pulp pH value was 8, Ca2+, Fe3+, and Ba2+ concentration was 3×10-4 mol/dm3, 3×10-5 mol/dm3, and was 2×10-4 mol/dm3 respectively, and OHA collector dosage was 5×10-4 mol/dm3, while the flotation recoveries of monazite, calcite. And fluorite was above 95 %, 40.43 %, and below 45.32 %, and the recovery rate of barite and bastnaesite in the presence of Ca2+ and Fe3+ is below 54.32 % and 38.68 %, respectively and the effective separation of monazite and symbiotic ore was obtained. The zeta potential measurements showed that when only metal ions are added to monazite, monazite (IEP) shifts to the right, and the negative charge on the surface of monazite decreases, which may be due to the positive charge of metal ions adsorbed on the surface of monazite, increasing the positive charge on the surface of monazite. When Ca2+, Ba2+, Fe3+, and OHA were added to the monazite pulp, the IEP of monazite moved to the left, and the negative charge of monazite shifted to the positive direction as a whole, indicating that Ca2+, Ba2+, and Fe3+ were adsorbed on the surface of monazite and increase the positive charge on the surface of monazite. When the pH value was 7 ~ 10, the surface of monazite was the same as that before and after the action of the agent, and both were negatively charged. At this time, OHA can still adsorb on the calcite, that was, the chemical affinity overcomes the same electric repulsion and adsorbs, so that the potential of the monazite after the action is reduced, which is chemical adsorption. The FTIR showed that when the metal ions Ca2+, Ba2+, and Fe3+ are added to activate the surface of monazite, the peak area of the organic functional group-CH2−CH3 at 3000-2800 cm−1 was enhanced, and a new peak appears at 1382 cm−1. The reason is that the N-O-H functional group of OHA collector was adsorbed on the surface of monazite, and a red shift (44 cm−1) occurs, and a new peak appears at 1454 cm−1. The reason is that the C-N functional group of OHA collector is adsorbed on the surface of monazite. The lone electron pair of the nitrogen atom of the amide group in the OHA forms chelates with Ca2+, Ba2+, and Fe3+ atoms, which further increases the adsorption amount of OHA. This showed that the adsorption of monazite surface by metal ions provides active sites for the adsorption of OHA collectors. These phenomena indicate that the adsorption capacity of OHA on the surface of monazite activated by Ca2+, Ba2+, and Fe3+ is enhanced and a stable five-membered ring metal chelate is formed. Combined with flotation results and zeta potential data, infrared spectroscopy analysis, the adsorption capacity of Ca2+, Ba2+, and Fe3+ activated monazite surface: Fe3+>Ca2+>Ba2+.

2

An Overview of Rare Earth Ores Beneficiation in Vietnam

Nhu Thi Kim Dung, Pham Van Luan, Vu Thi Chinh, Tran Van Duoc

Inżynieria Mineralna

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2021

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no. 2

227--236

EN

Rare earth metals are used in electricity, electronics, nuclear, optics, space, metallurgy, superconducting and super magnetic materials, glass and ceramics, and agriculture. Some rare earth elements are added to fertilizers for crops and some trials for animal feed. Rare earth elements, except for radioactive promethium, are relatively abundant in the earth's crust. Vietnam has a tremendous rare earth potential, distributed mainly in the Northwest, including Nam Xe, Dong Pao, Muong Hum, and Yen Bai. There are many research projects on rare earth ores of different types globally, but the focus is mainly on the essential minerals, including monazite, xenotime, and bastnaesite. This report summarizes research data on rare earth ore intending to produce a general assessment of rare earth ore and its beneficiation technology in Vietnam.

3

Monazite-bearing post processing wastes and their potential economic significance

Zglinicki Karol, Szamałek Krzysztof, Konopka Gustaw

Gospodarka Surowcami Mineralnymi

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2020

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T. 36, z. 1

37--58

EN

During the geological prospecting works conducted in 2013 on Bangka Island (Indonesia), high monazite content was identified in the wastes produced during processing of cassiterite deposits. Monazite, among 250 known minerals containing REE, is one of the most important minerals as primary source of REE. The monazite content in this waste is up to 90.60%. The phase composition of the investigated tailing proves that the sources of minerals accompanying the placer sediments tin mineralization are granitoids. The tailing is composed of numerous ore minerals, including monazite, xenotime, zircon, cassiterite, malayaite, struverite, aeschynite-(Y), ilmenite, rutile, pseudorutile and anatase. Monazite grains belong to the group of cerium monazite. Its grains are characterized by high content of Ce2O3 27.12–33.50 w t.%, La2O3 up to 15.46 w t.%, Nd2O3 up to 12.87%. The total REE2O3 + Y content ranges from 58.18 to 65.90 wt.%. Monazite grains observations (SEM-BSE) revealed the presence of porous zones filled with fine phases of minerals with U and Th content. The radiation intensity of 232Th is ATh = 340 ± 10 Bq and 238AU = 114 ± 2 Bq. High content of monazite and other REE minerals indicates that tailing is a very rich, potential source of REEs, although the presence of radioactive elements at the moment is a technological obstacle in their processing and use. The utilization of monazite bearing waste in the Indonesian Islands can be an important factor for development and economic activation of this region and an example of the good practice of circular economy rules.

PL

W trakcie geologicznych prac prospekcyjnych prowadzonych w 2013 roku na indonezyjskiej wyspie Bangka stwierdzono wysokie zawartości monacytu w odpadach powstałych po przeróbce osadów kasyterytonośnych. Monacyt jest jednym z najważniejszych pierwotnych źródeł REE wśród 250 znanych minerałów zawierających REE. Zawartość monacytu w badanym odpadzie wynosi do 90,60%. Skład fazowy badanych odpadów wskazuje, że źródłem minerałów towarzyszących w cynonośnych złożach okruchowych były granitoidy. W składzie odpadu przeróbczego, metodą XRD zidentyfikowano obecność licznych minerałów złożowych, wśród nich: monacyt, ksenotym, cyrkon, kasyteryt, malayait, strüveryt, aeschynit-(Y), ilmenit, rutyl, pseudorutyl i anataz. Badania składu chemicznego ziaren monacytu z użyciem EPMA ujawniły, że należy on do grupy monacytu cerowego. Jego ziarna cechują się wysoką zawartością Ce2O3 27,12–33,50% wt., La2O3 do 15,46% wt., Nd2O3 do 12,87%. Całkowita zawartość REE2O3 + Y mieści się w zakresie od 58,18 do 65,90% wt. Obserwacje ziaren monacytu (BSE) ujawniły w nich obecność stref porowatych wypełnionych drobnymi fazami minerałów z udziałem U oraz Th. Aktywność promieniotwórcza 232Th wynosi ATh = 340 ± 10 Bq, a 238U = 114 ± 2 Bq. Wysoka zawartość monacytu oraz innych minerałów nośników REE wskazuje, że odpad przeróbczy stanowi bardzo bogate, potencjalne źródło pierwiastków ziem rzadkich, choć zawartość pierwiastków promieniotwórczych stanowi obecnie przeszkodę technologiczną w ich przetwarzaniu i wykorzystaniu. Wykorzystanie monacytonośnych odpadów z wysp Indonezji może być ważnym czynnikiem rozwoju i aktywizacji gospodarczej tego regionu oraz przykładem dobrej praktyki stosowania zasad gospodarki o obiegu zamkniętym.

4

Przegląd głównych minerałów pierwiastków ziem rzadkich : złoto XXI wieku

Ryder P., Nowak M.

Przegląd Geologiczny

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2015

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Vol. 63, nr 6

348--362

EN

The constant evolution of civilisation and ever more advanced technologies have forced the global economy to search for new and renewable resources. Since the 1950s, rare earth elements (REE) have played an increasingly significant role in the production of new materials. The REE form a group of 17 elements (15 lanthanides, yttrium and scandium) with special properties that distinguish them from the other elements. These unique and essential raw materials have numerous applications nowadays. Without the rare earths, many branches of industry would not be able to function. The main resources of the REE come from the rocks with mineralization enriched in minerals with a higher REO (rare earth oxides) contents. Although there are around 270 different REE-bearing mineral species, the exploitation of the REE refers to less than 10 minerals. Five major REE minerals (the major minerals from group of bastnäsite (bastnaesite), monazite, xenotime, apatite and perovskite (loparite)) are characterized and described. The REO percentage content varies from max. 16% in apatite to max. 79% in bastnäsite. The examples shown were chosen due to their importance and level of extraction. This review-paper has been based on the compilation of data from mineralogical publications, mineralogical data websites and metallurgical articles about the alloys and their compounds.

5

Monazite Th-U-total Pb geochronology and P-T thermodynamic modelling in a revision of the HP-HT metamorphic record in granulites from Stary Gierałtów (NE Orlica-Śnieżnik Dome, SW Poland)

Budzyń B., Jastrzębski M., Kozub-Budzyń G. A., Konečný P.

Geological Quarterly

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2015

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Vol. 59, No. 4

700--717

EN

Thermodynamic modelling and monazite Th-U-total Pb dating via electron microprobe were used to improve the pressure, temperature and timing constraints of the HP-HT metamorphic record in granulites from Stary Gierałtów (NE Orlica-Śnieżnik Dome (OSD), SW Poland). The thermodynamic calculations constrained the P-T conditions to 20-22 kbar and ca. 920ºC in the felsic to intermediate granulites and 20-22 kbar and ca. 970ºC in the mafic granulite. These conditions are considered to closely represent the peak temperatures experienced by these rocks. In the intermediate granulite, the matrix monazite and monazite inclusions in garnet and allanite yielded an age of 349±2.5 Ma. An HP-HT metamorphic event with temperature conditions exceeding 900ºC, which are greater than the closure temperatures of most geochronometers, must have disturbed and completely reset the isotopic systems, including the Th-U-Pb system in the monazite. Consequently, this resetting prevented us from constraining the age of potential earlier metamorphic events or the igneous protolith. The 349±2.5 Ma age reflects the timing of the late-stage HP-HT event and cooling below 900ºC related to the initial exhumation of the granulites. A comparison of the new P-T-t constraints with previous data from the NE Orlica-Śnieżnik Dome indicates that the activation of the channels that exhumed the HP rocks to mid-crustal depths most likely initiated at ca. 350 Ma, and all the metamorphic rocks in the OSD likely shared a common Variscan evolution after ca. 340 Ma.

6

Stability of monazite and disturbance of the Th-U-Pb system under experimental conditions of 250–350 °C and 200–400 MPa

Budzyń B., Konečný P., Kozub-Budzyń G. A.

Annales Societatis Geologorum Poloniae

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2015

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Vol. 85, No. 2

405--425

EN

This experimental study provides important data filling the gap in our knowledge on monazite stability under conditions of fluid-mediated low-temperature metamorphic alteration and post-magmatic hydrothermal alterations. The stability of monazite and maintenance of original Th-U-total Pb ages were tested experimentally under P-T conditions of 250–350 °C and 200–400 MPa over 20–40 days. The starting materials included the Burnet monazite + K-feldspar ± albite ± labradorite + muscovite + biotite + SiO2 + CaF2 and 2M Ca(OH)2 or Na2Si2O5 + H2O fluid. In the runs with 2M Ca(OH)2, monazite was unaltered. REE-enriched apatite formed at 350 °C and 400 MPa. The presence of the Na2Si2O5 + H2O fluid promoted the strong alteration of monazite, the formation of secondary REE-enriched apatite to fluorcalciobritholite, and the formation of REE-rich steacyite. Monazite alteration included the newly developed porosity, patchy zoning, and partial replacement by REE-rich steacyite. The unaltered domains of monazite maintained the composition of the Burnet monazite and its age of (or close to) ca. 1072 Ma, while the altered domains showed random dates in the intervals of 375–771 Ma (250 °C, 200 MPa run), 82–253 Ma (350 °C, 200 MPa), and 95–635 Ma (350 °C, 400 MPa). The compositional alteration and disturbance of the Th-U-Pb system resulted from fluid-mediated coupled dissolution-reprecipitation. In nature, such age disturbance in monazite can be attributed to post-magmatic alteration in granitic rocks or to metasomatic alteration during metamorphism. Recognition of potentially altered domains (dark patches in high-contrast BSE-imaging, developed porosity or inclusions of secondary minerals) is crucial to the application of Th-U-Pb geochronology.

7

New potential source of rare earth elements

Szamałek K., Konopka G., Zglinicki K., Marciniak-Maliszewska B.

Gospodarka Surowcami Mineralnymi

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2013

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T. 29, z. 4

59--76

PL

Pierwiastki ziem rzadkich (REE) są niezwykle istotnym, choć rzadko występującym zasobem mineralnym odgrywającym ważną rolę w gospodarkach krajów wysoko rozwiniętych. Zakłócenia na międzynarodowym rynku surowcowym metali ziem rzadkich związane z monopolem Chin w zakresie ich produkcji i podaży zmuszają państwa wysoko rozwinięte do podejmowania intensywnych działań dla znalezienia nowych źródeł tych pierwiastków (wśród nich odpadów poprzeróbczych). W artykule przedstawiono wyniki badań składu mineralnego odpadów powstających na wyspie Bangka w trakcie wzbogacania koncentratu kasyterytowego. Badane próbki odpadów zawierają monacyt w ilości do 21,23 %w oraz do 17,55 %w ksenotymu (próbka z Sungkap, Bangka), ponadto występują w nich cyrkon, ilmenit, anataz, rutyl, pseudorutyl i kasyteryt. Poza pierwiastkami REE – zidentyfikowano niob i tantal w żużlu powstającym podczas wytopu cyny. Autorzy oceniają, że rocznie możliwe jest dostarczanie do dalszej przeróbki minimum 10 tys. ton minerałów zawierających pierwiastki ziem rzadkich (zarówno lekkich LREE obecnych w monacycie, jak i ciężkich HREE w ksenotymie).

EN

REE metals are a vital yet scarce resource which play a particularly significant role in developed countries and their technologically advanced economies. Disturbances in the international mineral commodities market for REE’s caused by the Chinese supply monopoly force industrialized countries to launch intensive programs to discover new sources of these elements (even considering post-processing tailings). This paper discusses the mineral composition of tailings obtained in cassiterite extraction on Bangka Island. The analyzed tailing samples contain up to 21.23%w monazite, up to 17.55%w xenotime (Sungkap, Bangka), as well as zircon, ilmenite, anatase, rutile, pseurorutile, and cassiterite. Aside fromREE’s, niobiumand tantalum were identified in slag formed during tin smelting. The authors estimate that annually a minimum of 10,000 tons of minerals containing REE’s (both LREE’s-monazite and HREE’s-xenotime) can be further processed.

8

Stability relationships of REE-bearing phosphates in an alkali-rich system (nepheline syenite from the Mariupol Massif, SE Ukraine)

Dumańska-Słowik M., Budzyń B., Heflik W., Sikorska M.

Acta Geologica Polonica

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2012

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Vol. 62, no. 2

247-265

EN

Primary REE-enriched fluorapatite and fluorbritholite-(Ce) in nepheline syenite from the Mariupol Massif (SE Ukraine), contain textural and chemical evidence of late- to post-magmatic metasomatic alteration. REE mobilization and replacement of the primary phases by fluid-mediated coupled dissolution-reprecipitation strongly depended on the distance between the altered minerals in the host rock. Fluorapatite and fluorbritholite-(Ce) forming individual pristine grains were partially replaced by the same phase with a new composition, resulting in the presence of patchy zoning in altered grains. the increased REE contents in altered fluorapatite rim domains are related to REE mobilization from the altered REE-depleted rim domains of the fluorbritholite-(Ce). The REEs were transported by a fluid with high F activity. The alteration of fluorapatite and fluorbritholite-(Ce) grains in contact resulted in the partial replacement of the primary phases by the same phase with a new composition, but also in the partial replacement of the fluorapatite by secondary monazite and fluorite. The REE mobilized from the fluorbritholite-(Ce) in the presence of a F-rich fluid in an alkali-rich system promoted formation of monazite as the new phosphate REE-host. The presence of secondary parisite in the altered domains of the fluorapatite and fluorbritholite-(Ce) indicates a CO2 component in the fluid during metasomatic alteration.

9

Chemistry of monazites as provenance indicator - case study from the Upper Silesia Coal Basin (Poland)

Kusiak M.A., Bakun-Czubarow N.

Studia Geologica Polonica

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2008

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Vol. 129

107-130

EN

Mineral chemistry and homogeneity, as well as crystal structure and unit cell parameters of detrital monazites isolated from sandstones of the Upper Silesia Coal Basin were studied using electron microprobe analysis (EPMA) and X-ray diffractometry (XRD). Analyzed monazite grains are chemically almost homogenous, only in a very few cases, parts of the grain are enriched in thorium and depleted in yttrium content. Typical feature of monazite from the Poruba Beds is relatively high content of Y (up to 4 wt. % Y2O3), what could point to higher temperature of crystallization. Monazite from the Kwaczała Arkose are, on average, richer in huttonite and slightly poorer in cheralite end-members than monazite from the Poruba Beds. Monazite from Kwaczała Arkose reveals the following unit cell parameters: a = 6.794(1) A*, b = 7.008(2) A*, c = 6.479(2) A*, b = 103.82(2)°, whereas for the Poruba Beds monazite these parameters, excluding b-value, are slightly higher: a = 6.804(3) A*, b = 7.002(5) A*, c = 6.488(4) A*, b = 103.85(3)°.

10

Whole rock major element influences on monazite growth: examples from igneous and metamorphic rocks in the Menderes Massif, western Turkey

Catlos E. J., Baker C. B., Çemen I., Ozerdem C.

Mineralogia

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2008

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Vol. 39, iss. 1/2

7--30

EN

Monazite (LREEPO4) is a radiogenic, rare-earth bearing mineral commonly used for geochronology. Here we examine the control of major element chemistry in influencing the crystallization of monazite in granites (Salihli and Turgutlu bodies) and garnet-bearing metamorphic assemblages (Bozdag and Bayindir nappes) from the Menderes Massif, western Turkey. In S-type granites from the massif, the presence of monazite correlates to the CaO and Al2O3 content of the whole rock. Granites with monazite only are low Ca (0.6–1.8 wt% CaO). As CaO increases (from 2.1–4.6 wt%), allanite [(Ce,Ca,Y)2(Al,Fe3+)3(SiO4)3(OH)] is present. Higher Al2O3 (>15 wt%) rocks contain allanite and/or monazite, whereas those with lower Al2O3 contain monazite only. However, examining data reported elsewhere for A-type granites, the correlation between major element chemistry and presence of monazite is likely restricted to S-type lithologies. Pelitic schists of the Menderes Massif show no correlation between major element chemistry and presence of monazite. One Bayindir nappe sample contains both prograde garnets and those affected significantly by diffusion. These rocks have likely experienced a complicated multi-stage tectonic history, which influenced their current mineral assemblages. The presence of monazite in a metamorphic rock can be influenced by the number, duration, and nature of events that were experienced and the degree to which fluids were involved. The source of monazite in the Bayindir and Bozdag samples was likely reactions that involved allanite. These reactions may not have significantly changed the bulk composition of the rock.

11

Thermochemical characterization of Ca4La6(SiO4)6(OH)2 a synthetic La- and OH-analogous of britholite: implication for monazite and LREE apatites stability

Janots E., Brunet F., Goffe B., Poinssot C., Burchard M., Cemic L.

Mineralogia

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2008

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Vol. 39, iss. 1/2

41--52

EN

In this contribution, monazite (LREEPO4) solubility is addressed in a chemical system involving REE-bearing hydroxylapatite, (Ca,LREE)10(PO4,SiO4)6(OH)2. For this purpose, a synthetic (La)- and (OH)-analogous of britholite, Ca4La6(SiO4)6(OH)2, was synthesised and its thermodynamic properties were measured. Formation enthalpy of –14,618.4 ± 31.0 kJ·mol–1 was obtained by high-temperature drop-solution calorimetry using a Tian-calvet twin calorimeter (Bochum, Germany) at 975 K using lead borate as solvent. Heat capacities (Cp) were measured in the 143–323 K and 341–623 K ranges with an automated Perkin-Elmer DSC 7. For calculations of solubility diagrams at 298 K, the GEMS program was used because it takes into account solid solutions. In conditions representative of those expected in nuclear waste disposal, calculations show that La-monazite is stable from pH = 4 to 9 with a minimum of solubility at pH = 7. La-bearing hydroxylapatite precipitates at pH > 7 with a nearly constant composition of 99% hydroxylapatite and 1% La-britholite. Each mineral buffers solution at extremely low lanthanum concentrations (log{La} = 10–10–10–15 mol·kg–1 for pH = 4 to 13). In terms of chemical durability, both La-monazite and La-rich apatite present low solubility, a requisite property for nuclear-waste forms.

12

Genesis and stability of accessory phosphates in silicic magmatic rocks: a Western Carpathian case study

Broska I., Perik I.

Mineralogia

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2008

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Vol. 39, iss. 1/2

53--65

EN

The formation of accessory phosphates in granites reflects many chemical and physical factors, including magma composition, oxidation state, concentrations of volatiles and degree of differentiation. The geotectonic setting of granites can be judged from the distribution and character of their phosphates. Robust apatite crystallization is typical of the early magmatic crystallization of I-type granitoids, and of late magmatic stages when increased Ca activity may occur due to the release of anorthite from plagioclase. Although S-type granites also accumulate apatite in the early stages, increasing phosphorus in late differentiates is common due to their high ASI. The apatite from the S-types is enriched in Mn compared to that in I-type granites. A-type granites characteristically contain minor amounts of apatite due to low P concentrations in their magmas. Monazite is typical of S-type granites but it can also become stable in late I-type differentiates. Huttonite contents in monazite correlate roughly positively with temperature. The cheralite molecule seems to be highest in monazite from the most evolved granites enriched in B and F. Magmatic xenotime is common mainly in the S-type granites, but crystallization of secondary xenotime is not uncommon. The formation of the berlinite molecule in feldspars in peraluminous melts may suppress phosphate precipitation and lead to distributional inhomogeneities. Phosphate mobility commonly leads to the formation of phosphate veinlets in and outside granite bodies. The stability of phosphates in the superimposed, metamorphic processes is restricted. Both monazite-(Ce) and xenotime-(Y) are unstable during fluid-activated overprinting. REE accessories, especially monazite and allanite, show complex replacement patterns culminating in late allanite and epidote formation.

13

Rewizja wieku "najstarszych" skał w podłożu krystalicznym północno-wschodniej Polski

Krzemińska E., Wiszniewska J., Williams I.S.

Przegląd Geologiczny

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2006

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Vol. 54, nr 11

967-967, 973

EN

The oldest geochronological results between 2.69–2.57 Ga was previously obtained by using K–Ar method on biotite from pegmatite from Jastrzębna IG–1 borehole. In consequence, in many published reports up to 1998, the Mazowsze (or Masovian) granitoid massif has been regarded as Archean age structure. Therewithal, other rocks in the area, e.g. Bargłów gneiss sequence traditionally were described as Archean in age. In the paper we present new U–Pb SHRIMP zircon and monazite results for above mentioned rocks which have been considered as Archean. Cathodoluminescence images and SHRIMP analysis were carried out for zircons and monazites from Jastrzebna IG–1 pegmatite of 514 m depth (a historical sample previously dated by K–Ar method) and for zircon magmatic cores from Bargłów IG–2 orthogneiss of the 708 m depth. The obtained U–Pb ages of 1826 š12 Ma (zircon) and 1789š34 Ma (monazite), and 1835š28 Ma (zircon) for two rock samples respectively have shown Paleoproterozoic origin. Only 4 of the 24 analysed zircons have clearly discordant results, which are all from the Jastrzebna pegmatite, where Pb–loss was possible (in partially metamict U–rich zircon grains). The new U–Pb SHRIMP dating indicates that Jastrzębna pegmatite and Bargłów magmatic protolith of the orthogneiss is only Late Paleoproterozoic in age and in general about 700 Ma younger than previously reported by K–Ar method. Therefore, there is no unequivocal evidence of the presence of Archean rocks in crystalline basement of NE Poland. This study has been undertaken as a part of a collaborative research agreement between the Polish Geological Institute and Geochronology and Isotope Geochemistry Research School of Earth Sciences of the Australian National University in Canberra.

14

In situ growth of monazite in anchizonal to epizonal mudrocks: first record from the Variscan accretionary prism of the Kaczawa Mountains, West Sudetes, SW Poland

Kryza R., Zalasiewicz J. A., Charnley N., Milodowski A. E., Kostylew J., Tyszka R.

Geologia Sudetica

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2004

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Vol. 36

39-51

EN

We report the first occurrence of diagenetic or low grade metamorphic monazite from the Palaeozoic mudrock successions of the Kaczawa Complex of the West Sudetes, Poland. Where observed in relation to the enclosing mudrock, this monazite comprises tiny irregular grains, less than 20 microns in diameter, intergrown with the surrounding matrix minerals. This monazite resembles previously described examples of diagenetic monazite from elsewhere in the world in mostly possessing low contents of Th and U but differs in forming much smaller grains, which show only slight zonation of rare earth elements (REEs). Some of the monazite grains studied also appear to have formed synchronously with the cleavage, perhaps a function of early deformation and fluid release in an accretionary prism environment. Relatively Th-rich cores, and an association with altered detrital biotite in some instances, suggests that at least some of the in situ monazite growth might have taken place as overgrowths on primary detrital monazite particles.