Xenotime is a rare-earth phosphate mineral , the major component of which is yttrium orthophosphate Y P O 4. It forms a solid solution series with chernovite- Y Y As O 4 and therefore may contain trace impurities of arsenic , as well as silicon dioxide and calcium. The rare-earth elements dysprosium , erbium , terbium and ytterbium , as well as metal elements such as thorium and uranium all replacing yttrium are the expressive secondary components of xenotime. Due to uranium and thorium impurities, some xenotime specimens may be weakly to strongly radioactive. Lithiophyllite , monazite and purpurite are sometimes grouped with xenotime in the informal “anhydrous phosphates” group. Xenotime is used chiefly as a source of yttrium and heavy lanthanide metals dysprosium, ytterbium, erbium and gadolinium. Occasionally, gemstones are also cut from the finest xenotime crystals. The criticism was blunted, as over time “kenotime” was misread and misprinted “xenotime”.
SHRIMP Uranium-Lead Dating of Diagenetic Xenotime in Siliciclastic Sedimentary Rocks
Passarelli; Miguel A. Basei; Oswaldo Siga Jr. Sproesser; Vasco A.
U-Pb zircon-xenotime-monazite dating and Hf-isotope tracing to distinguish Cretaceous and Paleogene granitoids in the Western Rhodopes and Rila Mountain.
Farley, Kenneth A. Reviews in Mineralogy and Geochemistry. ISBN Full text is not posted in this repository. Consult Related URLs below. For example, apatite usually has a few tens of ppm of both U and Th, while monazite and xenotime usually have hundreds of ppm to weight percent levels of these elements. As a consequence, these phosphates can be dated using several fundamentally different isotopic techniques.
Helium Diffusion in Natural Xenotime
Xenotime is an ideal mineral for U-Th-Pb isotopic dating because of its relatively high U and Th contents, but typically low concentration of common Pb. These characteristics, and the fact that it is widespread throughout various types of rocks, suggest that the U-Th-Pb dating of xenotime has broad applications. To evaluate the reliability of our method, a xenotime standard, BS-1, was analyzed and calibrated against another xenotime standard, MG We also analyzed xenotimes in leucogranites from South Tibet and granites from Xihuashan in southern China, and obtained accurate and precise ages.
Igneous ones should be easily dated by LA-ICPMS or SIMS technique. For metamorphic one, I would suggest that you carry out your dating spots directly on.
Tatry Mountains orthogneisses Western Carpathians,. Box , 05 Bratislava, Slovak Republic;. Manuscript received September 12, ; accepted in revised form March 16, Biotite- hosted monazite is commonly overgrown by thin REE-epidote rims, in a less foliated sample it is apparently unstable and breaks down to apatite, REE-epidote and a Th-silicate huttonite? Empirical thermometers based on Y in monazite give — Extensive dating by Cameca SX microprobe yielded a range of ages: the.
Because monazite recrystallized at subsolidus temperatures it seems to have failed to record a magmatic age. However, an Ordovician core ca. Decompression-related muscovite melting was probably the reason for the partial melt formation. Both banded stroma- tite and augengneiss ophthalmite varieties occur togeth- er with paragneisses and amphibolites. While earlier authors treated orthogneisses as migmatites e.
SHRIMP U-Pb geochronology of authigenic xenotime and its potential for dating sedimentary basins
Data points are arrayed linearly and enable us to define an isochron which passes through the origin. The chemical Th-U-total Pb isochron ages coincide well with mineral and whole-rock ages isotopically determined for the same samples. The chemical Th-U-total Pb isochron method was applied to the age determination of monazite, zircon and xenotime from the Tsubonosawa paragneiss and the host Hikami granite in the South Kitakami terrane of Northeast Japan.
The Ma event corresponds to the intrusion of the Hikami granite, and the Ma one to the intrusion of the Cretaceous Kesengawa granite. The and Ma events may correspond in age to the main metamorphic event and subsequent igneous activity in the Hida terrane, central Japan. The chemical Th-U-total Pb isochron age in terms of the precise microprobe analysis of low-level Th, U and Pb will open a new vista on the Paleozoic-Mesozoic tectonics of the Japanese Islands.
Frances Wall, Vistorina N. The Canadian Mineralogist ; 46 4 : — Xenotime- Y is a common accessory mineral in many igneous and high-grade metamorphic rocks, but it is very rare in carbonatite. Uniquely, at Lofdal, Namibia, xenotime- Y occurs in many carbonatite dykes. It mantles and replaces zircon in calcite carbonatite and also occurs as aggregates in ankerite carbonatite, aggregates associated with hematite, and crystals associated with monazite- Ce and synchysite- Ce in highly oxidized iron-rich calcite carbonatites.
The paragenetic sequence places the xenotime- Y at the end of magmatic activity and certainly into the hydrothermal stage. These features are most important in controlling the production of xenotime- Y at Lofdal. A Lofdal, en Namibie, on le trouve dans plusieurs filons de carbonatite.
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Monazite and xenotime from peraluminous granites in the middle to cooling path; crustal cross-section; U–Pb dating of monazite, xenotime and zircon.
Skup 21st meeting of the International Mineralogical Association. They formed during Sveconorwegian orogeny around 1 Ga ago. The electron microprobe analysis gave a monazite- Ce composition for both monazite samples concerned, with Ce2O3 ranging from The xenotime- Y sample contains A thorough SEM analysis using back-scattered electrons and energy-dispersive detector revealed numerous inclusions therein.
The xenotime sample also contains ThSiO4 inclusions with frequent uraninite inclusions. Zircon, mica and quartz are intimately intergrown with xenotime. Annealing experiments induced a slight decrease of unit cell volume ranging 0.
Canadian Journal of Earth Sciences
John N. Aleinikoff, a Karen Lund, a C. Mark Fanning b a U. The Belt—Purcell Supergroup, northern Idaho, western Montana, and southern British Columbia, is a thick succession of Mesoproterozoic sedimentary rocks with an age range of about — Ma. Stratigraphic layers within several sedimentary units were sampled to apply the new technique of U—Pb dating of xenotime that sometimes forms as rims on detrital zircon during burial diagenesis; xenotime also can form epitaxial overgrowths on zircon during hydrothermal and metamorphic events.
Additionally, all samples that yielded xenotime were also processed for detrital zircon to provide maximum age constraints for the time of deposition and information about provenances; the sample of Prichard Formation yielded monazite that was also analyzed.
XENOTIME-(Y) FROM CARBONATITE DYKES AT LOFDAL, NAMIBIA: UNUSUALLY LOW LREE:HREE RATIO IN CARBONATITE, AND THE FIRST DATING OF.
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Clicking on the donut icon will load a page at altmetric. Find more information on the Altmetric Attention Score and how the score is calculated. The U—Pb geochronologic analysis of accessory minerals has played an important role in Earth and solar system science in constraining the ages of a wide variety of rocks and minerals.
Currently, the significant matrix effects observed between different accessory minerals and the lack of high-quality standards for many minerals of interest are the major limitations of its geochronological applications. In this study, we investigated the effects of the addition of oxygen, nitrogen, and water vapor before and after the ablation cell on the accuracy of the U—Pb dating of different minerals e. We found that the addition of water vapor, unlike that of oxygen and nitrogen, before the ablation cell can significantly suppress the matrix effects on U—Pb dating.
This can be attributed to the suppression of elemental fractionation in both the laser ablation and ICP ionization processes by the presence of water vapor.
In situ UPb dating of xenotime by laser ablation ( LA )-ICP-MS
Agard, P. Jolivet, and B. DOI : Allaz, B. Selleck, M.
(A) shows results calculated for a sphere (narrow lines, radius indicated at top) of apatite, monazite, or xenotime composition. Bold lines give FT.
Kenneth A. Farley, Daniel F. Reviews in Mineralogy and Geochemistry ; 48 1 : — For example, apatite usually has a few tens of ppm of both U and Th, while monazite and xenotime usually have hundreds of ppm to weight percent levels of these elements. As a consequence, these phosphates can be dated using several fundamentally different isotopic techniques.
Elsewhere in this volume Harrison et al.
(U-Th)/He Dating of Phosphates: Apatite, Monazite, and Xenotime
Dating xenotime. May also offer opportunities for life? U-Pb dates are enriched in studying the xenotime—garnet relationships provide. Apr 25, andhra pradesh.
1 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing , China; 2 Graduate.
Data Portal List. Spatio-Temporal Dataset Search. Data Portal Monitor. Dataset Information. Title The age of the Telfer Au-Cu deposit and its relationship with granite emplacement, Paterson Province, Western Australia Description Dating of granites from the Telfer Region of the Paterson Province shows that felsic magmatism took place between ca. This magmatism is interpreted to be a result of deformation and crustal thickening associated with the Miles Orogeny, the first major compressional deformation to affect the Neoproterozoic sedimentary rocks of the Yeneena Basin.
These dates indicate that mineralisation took place over a relatively restricted period of time, at a similar time to the emplacement of the earliest granites of the Miles Orogeny, and was apparently unrelated to magmatism at ca. Although there is a close temporal relationship between the early granites and Au mineralisation, the lack of a close spatial association suggests that it is possible that granite emplacement was not directly involved in the mineralising system, but was instead a separate consequence of deformation associated with the Miles Orogeny.
If this was the case, then other parts of the Yeneena Basin affected by the Miles Orogeny, but not intruded by granites, could be prospective for lode-Au mineralisation. Publisher Geoscience Australia. Portal Information.
Diagenetic xenotime dating to constrain the initial depositional time of the Yan-Liao Rift
Official websites use. Share sensitive information only on official, secure websites. The Belt—Purcell Supergroup, northern Idaho, western Montana, and southern British Columbia, is a thick succession of Mesoproterozoic sedimentary rocks with an age range of about — Ma. Stratigraphic layers within several sedimentary units were sampled to apply the new technique of U—Pb dating of xenotime that sometimes forms as rims on detrital zircon during burial diagenesis; xenotime also can form epitaxial overgrowths on zircon during hydrothermal and metamorphic events.
Additionally, all samples that yielded xenotime were also processed for detrital zircon to provide maximum age constraints for the time of deposition and information about provenances; the sample of Prichard Formation yielded monazite that was also analyzed. We interpret the Prichard xenotime as diagenetic in origin.
Crystal-chemical constraints of U-Pb dating in monazite and xenotime from Aust-Agder pegmatites, Norway // 21st meeting of the International Mineralogical.
The basal boundary age of the Lower Changcheng Group indicates the initial time of the NCC as a stable cratonic block and can be used to make correlations among several representative basins worldwide. Recent studies have debated the initial depositional time of the Changcheng System, which is the key to understanding the Proterozoic tectonic evolution of the NCC. This study documented the xenotime and monazite from the lowermost Changzhougou and Chuanlinggou Formations of the Changcheng Group.
The monazite grains from the Chuanlinggou Formation yielded U-Pb ages between Ma and Ma, which are comparable to the detrital zircon U-Pb ages in the same formation, indicating their detrital origin. Xenotime mostly occurs as overgrowths on the detrital zircon grains, supporting a post-depositional origin. The low U content of the Changzhougou Formation’s xenotimes indicates a hydrothermal origin.
These xenotime overgrowths yielded a wide age variation, even on a single grain, due to prolonged xenotime precipitation. The lowest boundary of the Changchengian System must be older than Ma. This work demonstrates that diagenetic xenotime could better constrain the depositional time; however, extensive systematic research is required, especially with higher spatial resolution and more diagenetic xenotime grains.
Diagenetic xenotime dating to constrain the initial depositional time of the Yan-Liao Rift. Overview Fingerprint. Access to Document Link to publication in Scopus.