This paper presents new data related to the emplacement ages of the Amakinskaya and Taezhnaya kimberlites of the Mirny field, Siberia, located in the southern part of the Yakutian diamondiferous province. This study analyzed rutile and titanite grains along with zircons for U-Pb isotope composition by laser ablation LA -inductively coupled plasma-mass spectrometry ICP-MS and evaluated the applicability of rutile and titanite for the dating of kimberlite emplacements. Both minerals contain substantial admixtures of common Pb in their Pb isotope composition. Therefore, the Pb method was applied for common Pb correction during age calculation. All age estimates correspond to the main epoch of diamondiferous kimberlite activity in the Siberian platform and suggest the formation of the Mirny kimberlite field within a single event or two separate events occurring close together in time. Results obtained from this study indicate that rutile and titanite can be useful for the dating of kimberlite emplacements.
Chemical analyses show that rutile included in other minerals Rt inc commonly show higher SiO 2 and FeO contents and lower Nb 2 O 3 and ZrO 2 contents if compared with rutile in the matrix of the garnet-rich layer Rt mat. Cr 2 O 3 concentrations are quite similar in both types of rutile. Rt mat commonly shows a greater variability in minor elements, especially Nb 2 O 3 0. Few compilations of geochemical and geochronological data on rutile in Variscan metabasites can be found in literature, thus these data represent a new insight on a mineral phase the significance and scientific interest of which are rising in the last years.
Future studies on the origin and ages of emplacement and metamorphism either prograde or retrograde of this kind of rock, widespread in the Variscan chain, will benefit from these data as a term of comparison.
Zircon is the most commonly used mineral in U-Pb dating but monazite, apatite, xenotime, titanite, rutile, baddeleyite, perovskite and allanite are also used and.
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Schmitt and T. Schmitt , T. Zack Published Geology Chemical Geology. View via Publisher. Save to Library. Create Alert. Launch Research Feed. Share This Paper. Magee, J. Ferris
In situ U-Pb rutile dating by LA-ICP-MS
Passarelli; Miguel A. Basei; Oswaldo Siga Jr. Sproesser; Vasco A. It provides reliable and accurate results in age determination of superposed events. However, the open-system behavior such as Pb-loss, the inheritance problem and metamictization processes allow and impel us to a much richer understanding of the power and limitations of U-Pb geochronology and thermochronology. Since , the Interdepartmental Laboratory of Isotopic Geology focus the study of the Earth’s geologic processes, dealing with themes such as plate tectonics, plutonism, volcanism, sedimentary rocks, tectono-thermal evolution, and more recently environmental studies.
In situ U-Pb rutile dating by LA-ICP-MS: Pb correction and prospects for geological applications. Research output: Contribution to journal ›.
To browse Academia. Skip to main content. Log In Sign Up. Download Free PDF. Richard Hinton. Elena Belousova. Matthias Barth. Thomas Zack. George Luvizotto.
U-Pb LA-ICPMS dating using accessory mineral standards with variable common Pb
Help Contact us. Bracciali, Laura. Geosciences , 9 The significant and continuous improvement of instrumentation and approaches has opened new fields of applications by extending the range of minerals that can be dated by this method. Following the development and distribution to the community of good quality reference materials in the last decade, rutile U-Pb thermochronology with a precision only slightly worse than zircon has become a commonly used method to track cooling of deep-seated rocks.
Recrystallization and secondary growth during metamorphism and the presence of grain boundary fluids can also affect the U-Pb isotopic system in rutile.
Zircon, rutile, and haematite occur as accessory phases in the tuff. Ling, W. L., Xie, X. J., Liu, X. M. & Cheng, J. P. Zircon U-Pb dating on the.
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Time resolved rutile U/Pb data derived from LA-ICPMS – a case study from the North Pamir
Abstract In situ laser ablation ICP-MS U—Pb dating of metamorphic rutile from granulite facies metapelitic rocks of the Archaean Pikwitonei granulite domain Manitoba, Canada provides constraints on Pb diffusion and characterizes the closure behavior of rutile. Age profiles indicate that volume diffusion of Pb occurs in rutile implying that the ages represent cooling ages. To investigate the closure behavior of Pb in rutile closure temperature profiles T c x were constructed based on different models combined with experimentally-determined diffusion parameters.
The classical T c x model of Dodson ; Mat. Forum 7, — indicates a rapid decrease of T c in the rims of grains, providing unrealistic estimates for the cooling rate when combined with U—Pb ages.
Abstract In situ laser ablation ICP-MS U–Pb dating of metamorphic rutile from granulite facies metapelitic rocks of the Archaean Pikwitonei granulite domain.
Chemical Geology , , pp. View at publisher. LA-ICPMS dating of these U-bearing accessory phases typically requires a matrix-matched standard, and data reduction is often complicated by variable incorporation of common Pb not only into the unknowns but also particularly into the reference material. Common Pb correction of the age standard can be undertaken using either the Pb, Pb or Pb no Th methods, and the approach can be applied to raw data files from all widely used modern multi-collector and single-collector ICPMS instruments.
This downhole fractionation model is applied to the unknowns and sample-standard bracketing using a user-specified interpolation method is used to calculate final isotopic ratios and ages. Pb and Pb no Th corrected concordia diagrams and Pb, Pb and Pb no Th -corrected age channels can be calculated for user-specified initial Pb ratio s. All other conventional common Pb correction methods e.
The secondary Durango McClure Mountain The suitability of the Pb no Th -correction is demonstrated by the agreement between a U-Pb TW concordia intercept age of
Geochemical and geochronological dataset of rutile from a Variscan metabasite in Sardinia, Italy
Providing customized analytical solutions at the highest standards of quality assurance and quality control. Samples for U-Pb dating are processed using a Rhino jaw crusher, a Bico disk grinder equipped with ceramic grinding plates, and a Wilfley wet shaker table equipped with a machined Plexiglass top, followed by conventional heavy liquid and magnetic separation using a Frantz magnetic separator. Four binocular microscope workstations are available for sample picking.
The external morphology of mineral grains for analysis can be documented by SEM, and internal structure can be examined in polished grain mounts by cathodoluminescence imaging. TIMS U-Pb geochronology is widely recognized as one of the most robust and precise dating techniques. We have dated rocks from Pliocene to Archean in age, for clients from universities, government and industry.
Zircon U/Pb dating provides usually a crystallization age, while rutile gives cooling We present detrital rutile U/Pb data measured by Laser Ablation Inductively.
Rutile is a common accessory mineral that occurs in a wide spectrum of metamorphic rocks, such as in blueschists, eclogites, and granulites and as one of the most stable detrital heavy minerals in sedimentary rocks. The advent of rutile trace element thermometry has generated increased interest in a better understanding of rutile formation. Rutile thermometry of the same detrital grains indicates former granulite-facies conditions. The methods outlined in this paper should find wide application in studies that require age information of single spots, e.
Rutile is a common accessory mineral that is found in a wide range of rock types on Earth and beyond e. On Earth, all major rock types exhibit rutile-bearing samples. However, rutile forms predominantly in metamorphic rocks. In general, rutile is more common in metapelitic than in metamorphic rocks see the Ivrea example; Zingg ; Luvizotto and Zack and is more common in higher-pressure samples compared to their lower-pressure counterparts see discussion in Zack et al.
Clastic sediments are important rutile-bearing rocks since rutile is one of the most stable minerals during weathering, transport, and diagenesis Hubert ; Force ; Morton and Hallsworth Despite its common occurrence, rutile has so far received less attention as a geochronometer than zircon and monazite.
Rutile U-Pb Geochronology
Sedimentary sequences interbedded with tuff layers unconformably overlay metamorphic rocks in the Sulu Orogen.
Allanite U-Pb ages together with the petrographic support can provide the time of the peak metamorphism (Kim et al. ). Rutile is the most common TiO2.
Box , Beijing , P. E-mail: xieliewen mail. The advantages include high spatial resolution, high sample throughput, good precision and accuracy, and limited sample preparation. For the application of these techniques in U—Th—Pb geochronology, the main challenges involve ion counter drift, matrix differences between reference materials and samples, laser-induced downhole elemental fractionation and common lead corrections.
We review recent efforts to improve spatial resolution, calibrate ion counter drift, and correct for common lead contamination, elemental fractionation and matrix mismatching. Multi-collectors simultaneously measure all isotopic signals over flat-topped peaks so that 1 the detection efficiency is significantly improved and relatively high spatial resolution is obtained, 4,5 and 2 the effects of spectral skew and flicker noise from the plasma source or ablated particles are removed or significantly reduced, resulting in improved counting statistics and lower internal and external uncertainties in isotopic ratios.
The coupling of laser systems and more than one MS system where the carrier gas flow and, therefore, the ablated product is split between the mass spectrometers has been termed laser ablation split stream LASS analysis. Recent improvements in ultra-high spatial resolution U—Th—Pb dating is reviewed, as is the current state of LASS analysis in various mineral phases. Finally, we present our perspective on future developments that might further resolve the challenges associated with these techniques.
To improve the precision of measurements obtained using small ion beams on MFC systems, amplifiers equipped with 10 12 and 10 13 ohm resistors in the feedback loop were developed, increasing the gain by a factor of 10 and times and improving the theoretical signal to noise ratio by a factor of 3 and 10, respectively, compared to the default 10 11 ohm resistors.
In contrast, the MIC system provides a powerful ability to measure small ion signals, which are the norm for high spatial resolution U—Th—Pb dating. Some aspects of MIC systems, such as non-linear behavior, drift in counting efficiency depending on the count rate, and the difficulty in determining the IC dead time, can limit their precision.
When the operating voltage of a SEM is at its plateau, almost all incident ions are detected.
Storey, Martin Smith , T. N2 – In situ U—Pb dating of a variety of mineral phases is an important goal in petrology. This study reports data chiefly from titanite, but also from rutile and apatite, obtained using the laser ablation LA -ICP-MS methodology on polished thick sections in order to retain as much petrologic information as possible, and allowing trace element analyses from adjacent areas to the U—Pb analyses.
The samples analysed come from Svecofennian intermediate to acid volcanic rocks of the Porphyry Group within the major iron ore province of Norrbotten, northern Sweden, where titanite is a common phase associated with the mineralisation. However, the data are a priori accurate as they are geologically reasonable.
U-Pb dating by LA ICP-MS is one of the most popular and successful isotopic techniques available to the Earth Sciences to constrain timing and rates of.
Stockli, George L. Luvizotto, Matthias G. Barth, Elena Belousova , Melissa R. Wolfe, Richard W. Rutile is a common accessory mineral that occurs in a wide spectrum of metamorphic rocks, such as in blueschists, eclogites, and granulites and as one of the most stable detrital heavy minerals in sedimentary rocks. The advent of rutile trace element thermometry has generated increased interest in a better understanding of rutile formation.
Rutile thermometry of the same detrital grains indicates former granulite-facies conditions. The methods outlined in this paper should find wide application in studies that require age information of single spots, e. N2 – Rutile is a common accessory mineral that occurs in a wide spectrum of metamorphic rocks, such as in blueschists, eclogites, and granulites and as one of the most stable detrital heavy minerals in sedimentary rocks. AB – Rutile is a common accessory mineral that occurs in a wide spectrum of metamorphic rocks, such as in blueschists, eclogites, and granulites and as one of the most stable detrital heavy minerals in sedimentary rocks.
High-precision U-Pb dating of accessory minerals to resolve timescales of geological processes. Or Triton TIMS was purchased from Thermo Scientific in and has been reliably serving for precise isotope ratio determination since then. The amplifiers of the 10 faraday cups were initially equipped with 5 1E12 Ohm, and 5 1E12 Ohm resistors.
U/Pb radiometric dating. U/Pb analyses were performed on rutile embedded in an epoxy resin mount. Thus, is not possible to assess whether.
This study investigates Ti mobility in the presence of halogens, as shown by the hydrothermal alteration of magmatic rutile in syenite. The syenite pegmatite studied intrudes gabbro, is preserved as a tectonic block in a major strike-slip fault zone, and formed in a back-arc environment in which there was widespread A-type granite plutonism.
Magmatic rutile in the syenite forms millimetric-scale crystals rimmed by magmatic titanite and magnetite and also occurs as smaller interstitial crystals. The syenite was synchronous with the later phases of regional A-type granite plutonism. Later hydrothermal halogen-rich fluids, derived from dissolution of halite, produced widespread metasomatic scapolite in the syenite.
Such fluids resulted in local dissolution-reprecipitation of Ti and Zr and resetting of the U-Pb system in the altered rutile, at Variations in dissolution and transport of Zr and Ti by halogen-rich fluids affect the Zr in rutile geothermometer, which yields unrealistic temperatures when applied in this study. More generally, the complexities of rutile chemistry in this hydrothermal setting could be reproduced in deeper subduction settings as a result of variations in halogen content of fluids released by prograde metamorphism.
Altree-Williams, A. Earth-Science Reviews, , — Andersen, T. Chemical Geology, , 59— Angiboust, S.