Szczegóły publikacji
Opis bibliograficzny
Stability of monazite and disturbance of the $Th-U-Pb$ system under experimental conditions of $250–350^{\circ}$C and 200–400 MPa / Bartosz Budzyń, Patrik Konečný, Gabriela A. KOZUB-BUDZYŃ // Annales Societatis Geologorum Poloniae ; ISSN 0208-9068. — 2015 — vol. 85 iss. 2, s. 405–424, Abstr. — Bibliogr. s. 417–419
Autorzy (3)
- Budzyń Bartosz
- Konečný Patrik
- AGHKozub-Budzyń Gabriela A.
Słowa kluczowe
Dane bibliometryczne
| ID BaDAP | 95223 |
|---|---|
| Data dodania do BaDAP | 2016-02-05 |
| Tekst źródłowy | URL |
| DOI | 10.14241/asgp.2015.016 |
| Rok publikacji | 2015 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | Annales Societatis Geologorum Poloniae |
Abstract
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 degrees C and 200-400 MPa over 20-40 days. The starting materials included the Burnet monazite + K-feldspar +/- albite +/- labradorite + muscovite + biotite + SiO2 + CaE, and 2M Ca(OH)(2) or Na2Si2O5 + H2O fluid. In the runs with 2M Ca(OH)(2), monazite was unaltered. REF-enriched apatite formed at 350 degrees C and 400 MPa. The presence of the Na2Si2O5 + H2O fluid promoted the strong alteration of monazite, the formation of secondary REF-enriched apatite to fluorcalciobritholite, and the formation of REF-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 degrees C. 200 MPa run), 82-253 Ma (350 degrees C, 200 MPa), and 95-635 Ma (350 degrees 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.
