Rutile u pb dating

01-Feb-2020 18:44

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Crystals larger than 0.5 mm yielded sufficiently precise Pb ratios to correct for the presence of common Pb, and individual rutile crystals often exhibited sufficient Pb isotopic heterogeneity to allow isochron calculations to be performed on replicate analyses of a single crystal.

The mean of 12 isochron ages is 1544 ± 8 Ma (2 SD), with isochron ages for single crystals having uncertainties as low as ±1.3 Myr (2 SD).

The of monazite ⩽0.1 mm in diameter, but significantly higher than the Rb-Sr system in muscovite (550 °C), phlogopite (435 °C) and biotite (400 °C). 600-640 °C for rutile 0.1-0.2 mm diameter cooled at 3 °C/Myr; near 600 °C [Cherniak D.

Even small rutile crystals are extremely resistant to isotopic resetting.

According to modern concepts, the closure temperature for the U-Pb system in rutile is higher than 500 °C, which suggests fairly high-temperature conditions of the rutile hydrothermal transformation during the formation of the deposits in Riphean. The rocks of the deposit are represented by light grey quartz sandstones, gritstones, conglomerates and conglobreccias, bedding between two thick layers at the base of the Pizhma glass quality quartz sandstones (D2pg) and higher than the ilmen-ite-leucoxene-quartz titaniferous stratum Malorucheiskaya of the Pizhemskoe deposit of Middle Timan [7, 8].

Obviously, a placer hypothesis of formation of titanium deposits of the Middle Timan which is supported by a number of researchers does not explain such temperature of rutile alteration. According to Rb-Sr isotopic data, the age of the titaniferous strata was determined as late Riphean - 685 ± 30 Ma [1].

Zircon dissolution controls the Hf isotope composition of subsequently-formed phases, which has implications for the interpretation of Hf isotope signatures in both metamorphic and magmatic settings.

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The main minerals among the 50 indicated are quartz, rutile, anatase, niobium rutile, ilmenite, zircon, mona-zite, columbite, garnets, chromespinelide, tourmaline, staurolite, gold with silver impurities, rounded diamonds of the Urals-Brazilian type [8].

AA(School of Earth Sciences, Victoria University of Wellington, P. Box 600, Wellington, New Zealand), AB(School of Earth Sciences, Victoria University of Wellington, P. Box 600, Wellington, New Zealand; Danish Lithosphere Centre, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark) Rapid Pb-Pb dating of natural rutile crystals by laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) is investigated as a tool for constraining geological temperature-time histories. The new rutile ages, together with the other geochronological data from the region, support the interpretation that the Reynolds Range underwent prolonged slow cooling on a conductive geotherm, under nearly steady-state conditions. 3 °C/Myr persisted for at least 40 Myr followed the peak of high- T/low- P metamorphism to granulite-facies conditions, and probably continued at ca.

LA-MC-ICPMS was used to analyse Pb isotopes in rutile from granulite-facies rocks from the Reynolds Range, Northern Territory, Australia. High precision U-Pb ages of metamorphic rutile: applications to the cooling history of high-grade terranes.

A case study in the Permian lower crustal section of the Ivrea-Verbano Zone (IVZ) incorporated U-Pb dating, Zr thermometry and Hf isotope analysis of rutile.

The results demonstrate the robustness of the Hf isotope system in rutile even under conditions of high temperature (1000° C) metamorphism and crustal melting.Again, please keep their identity a secret Click on the "Continue" button search with your zip/postal code.

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