Inherited zircon and titanite UPb systems in an Archaean syenite from southwestern Australia: implications for UPb stability of titanite

Pidgeon, R. T.; Bosch, Delphine; Bruguier, Olivier

doi:10.1016/0012-821x(96)00068-4

Cited by 116 publications

(39 citation statements)

References 26 publications

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“…Early work suggested that the blocking temperature for titanite might be as low as c. 500 8C (Gascoyne 1986, and references therein), but a number of more recent studies, both theoretical and field-based, are in close agreement that it is .660-700 8C (Cherniak 1993;Schärer et al 1994;Scott & St-Onge 1995;Pidgeon et al 1996;Verts et al 1996;Zhang & Schärer 1996;Essex et al 1997;Hawkins & Bowring 1999;Essex & Gromet 2000;Frost et al 2000). Scott & St-Onge (1995) studied the effect of grain size upon closure temperature, following the theoretical study of Cherniak (1993), and concluded that the effective radius for diffusion in titanite is ,50 ìm.…”

Section: Significance Of U-pb Ages Of Metamorphic Titanitesmentioning

confidence: 97%

Late Precambrian U–Pb titanite age for peak regional metamorphism and deformation (Knoydartian orogeny) in the western Moine, Scotland

Tanner

Evans²

2003

JGS

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There has been controversy over the number and timing of orogenies in the Precambrian Moine block in the Scottish Caledonides since the earliest radiometric dating in the 1960s. This work challenges a recent hypothesis, that this sector of the Laurentian margin was subjected to continuous crustal extension between .900 and 470 Ma. U-Pb dating (thermal ionization mass spectrometry) of titanite from a calcsilicate pod in the Moine (Morar Group) of the western Highlands gives an age of 737 AE 5 Ma. The titanite grew from Fe-Ti-bearing detrital minerals during the main progressive, syn-D 2 , amphibolite-facies (sillimanite zone) regional metamorphism, thus demonstrating that a Neoproterozoic contractional tectonothermal event (Knoydartian orogeny) affected the Moine block following the rift-related emplacement of the West Highland granite gneiss at 873 Ma. We conclude that the Sgurr Beag Thrust, a major tectonic break separating the Morar and Glenfinnan groups of the Moine, is mainly of Neoproterozoic, not Caledonian, age. The early tectonothermal event was succeeded by the Grampian Phase (Caledonian orogeny) at 460-470 Ma.

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Section: Significance Of U-pb Ages Of Metamorphic Titanitesmentioning

confidence: 97%

Late Precambrian U–Pb titanite age for peak regional metamorphism and deformation (Knoydartian orogeny) in the western Moine, Scotland

Tanner

Evans²

2003

JGS

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“…The 1784 ± 8 Ma and 1780 ± 12 Ma titanite ages from the porphyritic phase and granodioritic-tonalitic phase, respectively, date cooling through the ca. 650°C closure temperature of titanite (Scott & St-Onge 1995, Pidgeon et al 1996.…”

Section: U-pb Isotopic Datamentioning

confidence: 99%

Structural and magmatic evolution in the Loimaa area, southwestern Finland

Nironen¹

1999

Bull Geol Soc Finland

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“…It usually has relatively high U content (10-100 ppm [7]), which is commonly hold in its crystal lattice. It also has a relatively high U-Pb closure temperature of 650-700°C [9,10], making it an attractive phase as a geochronometer. Moreover, different with zircon and monazite, titanite is mainly composed by major elements of rocks, which easily exchange with other minerals and react with fluid and melt.…”

mentioning

confidence: 99%

“…Thus, it can record multistage metamorphism events, which are used to constitute the P-T-t path and to constrain the evolution of the metamorphic rocks [4][5][6][7]. The U-Pb ages of titanites in igneous rocks may represent the initial crystallization event because of the relatively uncommon occurrence of inherited older titanites in these rocks [10,11]; whereas, titanites in metamorphic rocks have different colors and distinct ages [7,11,12], recording multiple thermal events related to later metamorphism, deformation, and hydrothermal alteration of the rocks.…”

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confidence: 99%

In situ U-Pb dating of titanite by LA-ICPMS

Sun

Yang

et al. 2012

Chin. Sci. Bull.

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Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U, Th and Pb contents. Here, we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. Standards of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical methods. To check the matrix effect, titanite (BLR-1) and zircon (91500) standards were analyzed as the external standards. The weighted mean 206 Pb/ 238 U ages of OLT-1 titanite are 1015±5 Ma (2, n=24) and 1017±6 Ma (2, n=24) by single spot and line raster scan analyses, respectively, using BLR-1 titanite as the external standard. These ages are consistent with its reference age of about 1014 Ma. However, using 91500 zircon as the external standard, the weighted mean 206 Pb/ 238 U ages are 917±4 Ma (2, n=24) and 927±5 Ma (2, n=24) for BLR-1 titanite, and 891±4 Ma (2, n=24) and 901±5 Ma (2, n=24) for OLT-1 titanite by single spot and line raster scan analyses, respectively. It is evident that these ages are ~12% younger than their reference values. Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination, whereas it is insignificant between same minerals. Therefore, same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis. In addition, we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton, which indicates a rapid cooling history of this pluton. Isotopic geochronology is the key to understand the temporal and special evolution of geological bodies and their related geodynamics. There are many analytical methods to date isotopic ages of geological bodies, while the most commonly used is U-Pb dating of accessory minerals [1]. Minerals such as zircon and monazite have high uranium concentration and U-Pb closure temperature (T c(zircon) >800°C[2]; T c(Monazite)~7 50°C [3]) with low common lead, which makes them to be the preferred target for U-Pb dating. However, zircon and monazite are relatively stable and cannot be reset by the later thermal and chemical processes, due to its physical and chemical resistance. Thus, they are hardly used to constrain the later metamorphic ages of metamorphosed and hydrothermally altered rocks [4,5].Furthermore, some rocks (e.g. ultramafic rocks) do not contain zircon and monazite. Titanite (CaTiSiO 5 ) is one of the common accessory minerals in igneous rocks, and also occurring in metamorphic, hydrothermal and some sedimentary rocks [5][6][7][8]. It usually has relatively high U content (10-100 ppm [7]), which is commonly hold in its crystal lattice. It also has a relatively high U-Pb closure temperature of 650-700°C [9,10], making it an attractive phase as a geochronometer. Moreover, different with zircon and monazite, titanite is mainly composed by major elements of rocks, which easily exchange with other minerals and react with fluid and melt. ...

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Inherited zircon and titanite UPb systems in an Archaean syenite from southwestern Australia: implications for UPb stability of titanite

Cited by 116 publications

References 26 publications

Late Precambrian U–Pb titanite age for peak regional metamorphism and deformation (Knoydartian orogeny) in the western Moine, Scotland

Late Precambrian U–Pb titanite age for peak regional metamorphism and deformation (Knoydartian orogeny) in the western Moine, Scotland

Structural and magmatic evolution in the Loimaa area, southwestern Finland

In situ U-Pb dating of titanite by LA-ICPMS

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