Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Experimental constraints on the relative stabilities of the two systems monazite-(Ce) - allanite-(Ce) - fluorapatite and xenotime-(Y) - (Y,HREE)-rich epidote - (Y,HREE)-rich fluorapatite, in high Ca and Na-Ca environments under P-T conditions of 200-1000 MPa and 450-750 A degrees C
Polish Acad Sci, Res Ctr Krakow ING PAN, Inst Geol Sci, Senacka 1, PL-31002 Krakow, Poland..
Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany.;Univ Johannesburg, Dept Geol, POB 524, ZA-2006 Auckland Pk, South Africa..
AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al A Mickiewicza 30, PL-30059 Krakow, Poland..
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al A Mickiewicza 30, PL-30059 Krakow, Poland..ORCID iD: 0000-0002-6792-6866
2017 (English)In: Mineralogy and Petrology, ISSN 0930-0708, E-ISSN 1438-1168, Vol. 111, no 2, p. 183-217Article in journal (Refereed) Published
Abstract [en]

The relative stabilities of phases within the two systems monazite-(Ce) - fluorapatite - allanite-(Ce) and xenotime-(Y) - (Y,HREE)-rich fluorapatite - (Y,HREE)-rich epidote have been tested experimentally as a function of pressure and temperature in systems roughly replicating granitic to pelitic composition with high and moderate bulk CaO/Na2O ratios over a wide range of P-T conditions from 200 to 1000 MPa and 450 to 750 A degrees C via four sets of experiments. These included (1) monazite-(Ce), labradorite, sanidine, biotite, muscovite, SiO2, CaF2, and 2 M Ca(OH)(2); (2) monazite-(Ce), albite, sanidine, biotite, muscovite, SiO2, CaF2, Na2Si2O5, and H2O; (3) xenotime-(Y), labradorite, sanidine, biotite, muscovite, garnet, SiO2, CaF2, and 2 M Ca(OH)(2); and (4) xenotime-(Y), albite, sanidine, biotite, muscovite, garnet, SiO2, CaF2, Na2Si2O5, and H2O. Monazite-(Ce) breakdown was documented in experimental sets (1) and (2). In experimental set (1), the Ca high activity (estimated bulk CaO/Na2O ratio of 13.3) promoted the formation of REE-rich epidote, allanite-(Ce), REE-rich fluorapatite, and fluorcalciobritholite at the expense of monazite-(Ce). In contrast, a bulk CaO/Na2O ratio of similar to 1.0 in runs in set (2) prevented the formation of REE-rich epidote and allanite-(Ce). The reacted monazite-(Ce) was partially replaced by REE-rich fluorapatite-fluorcalciobritholite in all runs, REE-rich steacyite in experiments at 450 A degrees C, 200-1000 MPa, and 550 A degrees C, 200-600 MPa, and minor cheralite in runs at 650-750 A degrees C, 200-1000 MPa. The experimental results support previous natural observations and thermodynamic modeling of phase equilibria, which demonstrate that an increased CaO bulk content expands the stability field of allanite-(Ce) relative to monazite-(Ce) at higher temperatures indicating that the relative stabilities of monazite-(Ce) and allanite-(Ce) depend on the bulk CaO/Na2O ratio. The experiments also provide new insights into the re-equilibration of monazite-(Ce) via fluid-aided coupled dissolution-reprecipitation, which affects the Th-U-Pb system in runs at 450 A degrees C, 200-1000 MPa, and 550 A degrees C, 200-600 MPa. A lack of compositional alteration in the Th, U, and Pb in monazite-(Ce) at 550 A degrees C, 800-1000 MPa, and in experiments at 650-750 A degrees C, 200-1000 MPa indicates the limited influence of fluid-mediated alteration on volume diffusion under high P-T conditions. Experimental sets (3) and (4) resulted in xenotime-(Y) breakdown and partial replacement by (Y,REE)-rich fluorapatite to Y-rich fluorcalciobritholite. Additionally, (Y,HREE)-rich epidote formed at the expense of xenotime-(Y) in three runs with 2 M Ca(OH)(2) fluid, at 550 A degrees C, 800 MPa; 650 A degrees C, 800 MPa; and 650 A degrees C, 1000 MPa similar to the experiments involving monazite-(Ce). These results confirm that replacement of xenotime-(Y) by (Y,HREE)-rich epidote is induced by a high Ca bulk content with a high CaO/Na2O ratio. These experiments demonstrate also that the relative stabilities of xenotime-(Y) and (Y,HREE)-rich epidote are strongly controlled by pressure.

Place, publisher, year, edition, pages
SPRINGER WIEN , 2017. Vol. 111, no 2, p. 183-217
Keywords [en]
Monazite-(Ce), Xenotime-(Y), Allanite-(Ce), Epidote, Fluorapatite, Fluorcalciobritholite, Rare earth elements, Experimental petrology
National Category
Geophysics
Identifiers
URN: urn:nbn:se:uu:diva-322223DOI: 10.1007/s00710-016-0464-0ISI: 000398842400003OAI: oai:DiVA.org:uu-322223DiVA, id: diva2:1096382
Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-05-22Bibliographically approved

Open Access in DiVA

fulltext(19491 kB)101 downloads
File information
File name FULLTEXT01.pdfFile size 19491 kBChecksum SHA-512
12fe6428db9095855fc2cdd140003dba3a81899c46189502adac6e6c7808ec63dfd74ddedc450632de5d6810074ffbdd03a34afa9837ddc6ae26422f3ab49221
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Majka, Jaroslaw
By organisation
Mineralogy Petrology and Tectonics
In the same journal
Mineralogy and Petrology
Geophysics

Search outside of DiVA

GoogleGoogle Scholar
Total: 101 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 385 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf