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N. G. Rizvanova
N. G. Rizvanova
Institute of Precambrian Geology and Geochronology of Russian Academy of Sciences
Institute of Precambrian Geology and Geochronology of Russian Academy of Sciences

Articles

Geology
  • Date submitted
    2018-03-12
  • Date accepted
    2018-05-05
  • Date published
    2018-08-26

THE FIRST DATA ON THE U-PB AGE (TIMS AND LA-ICP-MS) OF RUTILE FROM THE ICHETJU POLYMINERAL OCCURRENCE, THE MIDDLE TIMAN

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A study on the U-Pb age of rutile from the Ichetju polymineral occurrence has been done for the first time by LA-ICP-MS and TIMS methods. It was established that rutile originates from various sources with different ages (presumably, ca. 1000, 1660, 1860 and 1980 Ma), but all the rutile types have undergone a common thermal event at ca . 580 Ma. Obtained results are consistent with U-Pb zircon data for the Ichetju occurrence and the Pizhemskoe deposit. According to modern concepts, the closure temperature for the U-Pb system in rutile is higher than 500  ° С, which suggests fairly high-temperature conditions of the rutile hydrothermal transformation during the formation of the deposits in Riphean. 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.

How to cite: Skublov S.G., Krasotkina A.O., Makeev A.B., Rizvanova N.G., Koiman E. THE FIRST DATA ON THE U-PB AGE (TIMS AND LA-ICP-MS) OF RUTILE FROM THE ICHETJU POLYMINERAL OCCURRENCE, THE MIDDLE TIMAN // Journal of Mining Institute. 2018. Vol. 232. p. 357. DOI: 10.31897/PMI.2018.4.357
Geology
  • Date submitted
    2017-01-08
  • Date accepted
    2017-02-25
  • Date published
    2017-06-25

Age of hydrothermal processes in the central iberian zone (Spain) according TO U-Pb dating of cassiterite and apatite

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Results of isotope-geochemical studies by PbLS step-leaching method of cassiterite from greisens located in Logrosán granite massif (Central Iberian Zone, Spain) and apatite from hydrothermal quartz-apatite vein on its exocontact indicate that in both cases a hydrothermal event is recorded in the interval of 114-126 Ma, which has been accompanied by lead supply. Within the limits of estimation error, the same age around 120 Ma corresponds to crystallization of hydrothermal apatite, formation of sticks and micro-inclusions in cassiterite from greisens and is suggested for Au-As-Sb-Pb ore mineralization, which calls for further confirmation. Xenogenous zircon from quartz-apatite vein does not react to this relatively low-temperature hydrothermal event either with building up new generations (sticks, areas of recrystallization) or with rebalancing of U-Pb isotope system. The age of greisen formation has been confirmed to be around 305 Ma by PbLS method on final phases of cassiterite leaching. Earlier it was estimated with 40 Ar/ 39 Ar method on muscovite. 

How to cite: Rizvanova N.G., Skublov S.G., Cheremazova E.V. Age of hydrothermal processes in the central iberian zone (Spain) according TO U-Pb dating of cassiterite and apatite // Journal of Mining Institute. 2017. Vol. 225. p. 275. DOI: 10.18454/PMI.2017.3.275