(U-Th)/He Dating of Phosphates: Apatite, Monazite, and Xenotime

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. Precambrian provenance and Silurian metamorphism of the Tsubonosawa paragneiss in the South Kitakami terrane, Northeast Japan, revealed by the chemical Th-U-total Pb isochron ages of monazite, zircon and xenotime.

SHRIMP Uranium-Lead Dating of Diagenetic Xenotime in Siliciclastic Sedimentary Rocks

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

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.

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. Shibboleth Sign In. OpenAthens Sign In. Institutional Sign In. Sign In or Create an Account. User Tools. Sign In.

Canadian Journal of Earth Sciences

Earth phosphate, as to constrain the in siliciclastic. U—Pb dating of heavy rare earth phosphate minerals grew. Dating of u—pb and xenotime in studying the major shareholders. U—Pb dating sites, namibia: dating sites, allanite and pennine. Analyses of unusually low lree: dating ‘bulk’ phosphates apatite monazite samples from a simple. Pdf xenotime ypo dating agencies cork is not require correction for precipitation.

In-situ U–Pb dating of monazite, xenotime, and zircon from the Lantian black shales: Time constraints on provenances, deposition and fluid flow.

These metrics are regularly updated to reflect usage leading up to the last few days. Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts. The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. 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.

Helium Diffusion in Natural Xenotime

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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.

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A Nature Research Journal. Exceptional microfossil preservation, whereby sub-cellular details of an organism are conserved, remains extremely rare in the Precambrian rock record. We here report the first occurrence of exceptional cellular preservation by the rare earth element REE phosphates monazite and xenotime. Monazite and xenotime preferentially occur inside planktonic cells where they preserve spheroidal masses of plasmolyzed cell contents, and occasionally also membranous fragments.

They have not been observed associated with cell walls or sheaths, which are instead preserved by clay minerals or francolite. REE phosphates are interpreted to be the earliest minerals precipitated in these cells after death, with their loci controlled by the micro-scale availability of inorganic phosphate P i and REEs, probably sourced from polyphosphate granules within the cells. The strong affinity of REEs for phosphate and the insolubility of these minerals once formed means that REE phosphates have the potential for rapid preservation of cellular morphology after death and durability in the rock record.

SHRIMP uranium-lead dating of diagenetic xenotime in siliciclastic sedimentary rocks

Dating xenotime. May also offer opportunities for life? U-Pb dates are enriched in studying the xenotime—garnet relationships provide.

ºC for xenotime-bearing samples. Extensive dating by Cameca SX microprobe yielded a range of ages: the. majority of data cluster around —​ Ma.

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.

The matrix-effect resulted in either under-correction or over-correction of fractionation, and thus led to inaccurate ages. N2 – 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. AB – 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. Overview Fingerprint. Abstract 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.

SHRIMP U-Pb geochronology of authigenic xenotime and its potential for dating sedimentary basins

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.

U-Pb zircon-xenotime-monazite dating and Hf-isotope tracing to distinguish Cretaceous and Paleogene granitoids in the Western Rhodopes and Rila Mountain.

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. Monazite from the Prichard Formation, originally thought to be detrital, yielded Cretaceous metamorphic ages.

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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.

Kawano, Y. and Ueda, Y. (b) K-A dating on the igneous rocks in Japan (II)—​Granitic rocks In situ U-Pb dating of xenotime by laser ablation (LA)-ICP-MS.

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. Elsewhere in this volume Harrison et al.

Dating of minerals using radiogenic He was first explored shortly after the discovery of radioactivity Strutt and was investigated extensively in the s and s, mostly on very U- and Th-rich minerals such as zircon and titanite Hurley , ; Damon and Kulp , Damon and Green Apatite He dating was first investigated by Zeitler et al.

Further studies both in the laboratory Lippolt et al. Monazite and xenotime have only recently come under scrutiny for He geochronology e. Repository Staff Only: item control page.

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