Alteration and chemical U-Th-total Pb dating of heterogeneous high-uranium zircon from a pegmatite from the Aduiskii massif, middle Urals, Russia

Zamyatin, D. A.; Shchapova, Yu. V.; Votyakov, S. L.; Nasdala, Lutz; Lenz, Christoph

doi:10.1007/s00710-017-0513-3

Cited by 21 publications

(20 citation statements)

References 94 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is mostly realised by combined incorporation of REE 3+ along with a pentavalent ion, either P 5+ (for Si 4+ ) or Nb 5+ /Ta 5+ (for Zr 4+ ; see Hoskin and Schaltegger, 2003; and references therein). Even though zircon has occasionally been reported to contain 10-30 wt.% Hf (Ma and Rossman, 2005;Pérez-Soba et al, 2007;Van Lichtervelde et al, 2009) or up to 13 wt.% U (Zamyatin et al, 2017), non-formula elements normally have low concentrations in this mineral. Other than Hf (with HfO 2 typically in the range 0.6-2.0 wt.%), all non-formula elements are well below the weightpercent level in gem-quality zircon.…”

Section: Introductionmentioning

confidence: 99%

Blue Zircon from Ratanakiri, Cambodia

Zeug¹,

Nasdala²,

Wanthanachaisaeng³

et al. 2018

Journ of Gemm

Self Cite

View full text Add to dashboard Cite

Zircon from Ratanakiri Province, northeastern Cambodia, is well known in the gem trade for its vivid blue colour that results from heat treatment. The untreated brown material turns blue under reducing conditions at ~900-1,000°C. Ratanakiri zircon is characterised by remarkably low contents of trace elements. In particular, the actinides have low concentrations (e.g. approximately 120 ppm U and 95 ppm Th). Together with the very young age of the zircon (<1 million years [Ma]), this results in an extremely low self-irradiation dose, which in turn is in agreement with its non-radiation-damaged, nearly perfectly crystalline state. The heat treatment, therefore, does not result in detectable changes in the zircon's structural state. The cause of the blue colour, presumably related to a valence change upon heating in the reducing environment, is still under debate. The absorption of the treated Ratanakiri zircon is decidedly different from that of blue U 4+-doped and blue V 4+-doped synthetic ZrSiO 4. Absorption spectra show a strongly pleochroic band at 18,200-13,000 cm-1 (corresponding to ~550-770 nm wavelength) that is clearly responsible for the treated blue colour; however, its assignment remains unresolved.

show abstract

Section: Introductionmentioning

confidence: 99%

Blue Zircon from Ratanakiri, Cambodia

Zeug¹,

Nasdala²,

Wanthanachaisaeng³

et al. 2018

Journ of Gemm

Self Cite

View full text Add to dashboard Cite

show abstract

“…An example for this is the mineral zircon (ZrSiO 4 ; tetragonal space group I 4 1 / amd ), which often is observed in a genuinely metamict (i.e. irradiation-amorphised) state (Capitani et al 2000 ; Nasdala et al 2002 ; Zamyatin et al 2017 ). A somewhat contrasting example is the mineral monazite–(Ce) [CePO 4 ; monoclinic space group P 2 1 / n ; the mineral nomenclature follows Lewinson ( 1966 ) and Bayliss and Levinson ( 1988 )] that typically shows rather moderate radiation damage in spite of significant Th concentrations (Seydoux-Guillaume et al 2007 ; Ruschel et al 2012 ).…”

Section: Introductionmentioning

confidence: 99%

Irradiation effects in monazite–(Ce) and zircon: Raman and photoluminescence study of Au-irradiated FIB foils

et al. 2018

Self Cite

View full text Add to dashboard Cite

Lamellae of 1.5 µm thickness, prepared from well-crystallised monazite–(Ce) and zircon samples using the focused-ion-beam technique, were subjected to triple irradiation with 1 MeV Au+ ions (15.6% of the respective total fluence), 4 MeV Au2+ ions (21.9%) and 10 MeV Au3+ ions (62.5%). Total irradiation fluences were varied in the range 4.5 × 1012 – 1.2 × 1014 ions/cm2. The highest fluence resulted in amorphisation of both minerals; all other irradiations (i.e. up to 4.5 × 1013 ions/cm2) resulted in moderate to severe damage. Lamellae were subjected to Raman and laser-induced photoluminescence analysis, in order to provide a means of quantifying irradiation effects using these two micro-spectroscopy techniques. Based on extensive Monte Carlo calculations and subsequent defect-density estimates, irradiation-induced spectroscopic changes are compared with those of naturally self-irradiated samples. The finding that ion irradiation of monazite–(Ce) may cause severe damage or even amorphisation, is in apparent contrast to the general observation that naturally self-irradiated monazite–(Ce) does not become metamict (i.e. irradiation-amorphised), in spite of high self-irradiation doses. This is predominantly assigned to the continuous low-temperature damage annealing undergone by this mineral; other possible causes are discussed. According to cautious estimates, monazite–(Ce) samples of Mesoproterozoic to Cretaceous ages have stored only about 1% of the total damage experienced. In contrast, damage in ion-irradiated and naturally self-irradiated zircon is on the same order; reasons for the observed slight differences are discussed. We may assess that in zircon, alpha decays create significantly less than 103 Frenkel-type defect pairs per event, which is much lower than previous estimates. Amorphisation occurs at defect densities of about 0.10 dpa (displacements per lattice atom).Electronic supplementary materialThe online version of this article (10.1007/s00269-018-0975-9) contains supplementary material, which is available to authorized users.

show abstract

“…Однако обычно подобный анализ осуществляют лишь на качественном уровне. На количественном уровне совместный анализ BSE-, CL-изображений с использованием JPD-методики [3] был реализован в [4,5] при изучении внутреннего строения (текстуры) зёрен циркона метамофитов и пегматитов. Актуальным представляется развитие и апробация JPD-методики на полигенных (полихронных) зёрнах циркона различного генезиса и строения с построением карт зональности зёрен как основы для их последующего локального U-Th-Pb-датирования, в том числе химического микрозондового при решении задач гео-и петрохронологии [6].…”

Section: геохимияunclassified

“…ДОКЛАДЫ АКАДЕМИИ НАУК том 485 № 4 2019 мер, [5]). По количеству точек определяли площадь каждой зоны.…”

Section: геохимияunclassified

“…-группировок, проявляющихся в виде дополнительных линий на спектрах РР, ФЛ минерала [5], -признаки вторичного преобразования этих зон, что может использоваться в качестве критерия нарушения его U-Pb-системы под действием водного флюида. Результаты химического датирования методом рентгеноспектрального микроанализа изменённых зон циркона Zrc-67, Ad1 существенно рассеяны и не несут смысловой нагрузки; напротив, локальные химические и изотопные датировки зон без признаков вторичных преобразований согласу-ются между собой и с общегеологическими представлениями об объектах [5,13].…”

Section: +unclassified

See 1 more Smart Citation

JPD-analysis as a new approach for studying the zircon texture with micron spatial resolution with application to geochronology

Zamyatin¹,

Votyakov²,

Shchapova³

2019

Доклады Академии наук

View full text Add to dashboard Cite

The polygenic and polychronous character of zircon texture is the key source of information on the conditions of its growth and secondary alterations. In this research the JPD method of processing of the BSE and CL images including plotting of JPD histograms and JPD maps of grains was developed and applied for quantitative study of the internal texture of zircon grains with micron spatial resolution and for its use in geochronometry. The nomenclature for distinguished zones on the generalized diagram (BSE vs. CL) is suggested for zircons of a wide range of the conditions of its formation, age, size, texture types, and degrees of structure disordering. The JPD-analysis of zircon internal texture is applied for interpretation of the nature of variations in the BSE and CL intensities within an individual heterogeneous grain (on the quantitative level) and between different grains (on the qualitative level). The approach is suggested as the preliminary stage during geochronological studies increasing the reliability of the local electron microprobe and mass spectrometry isotope dating of the mineral.

show abstract

Alteration and chemical U-Th-total Pb dating of heterogeneous high-uranium zircon from a pegmatite from the Aduiskii massif, middle Urals, Russia

Cited by 21 publications

References 94 publications

Blue Zircon from Ratanakiri, Cambodia

Blue Zircon from Ratanakiri, Cambodia

Irradiation effects in monazite–(Ce) and zircon: Raman and photoluminescence study of Au-irradiated FIB foils

JPD-analysis as a new approach for studying the zircon texture with micron spatial resolution with application to geochronology

Contact Info

Product

Resources

About