Browsing by Author "Villa I.M."

Browsing by Author "Villa I.M."

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  • CALL FOR AN IMPROVED SET OF DECAY CONSTANTS FOR GEOCHRONOLOGICAL USE 
    Begemann F.; Ludwig K.R.; Lugmair G.W.; Min K.; Nyquist L.E.; Patchett P.J.; Renne P.R.; Shih C.Y.; Villa I.M.; Walker R.J. (2001)
    The accuracy of radioisotopic ages is, at present, limited by the accuracy of radioactive decay constants. A literature survey reveals that decay constants used in geo- and cosmochronology usually are assigned uncertainties ...
  • DIRECT DETERMINATION OF 39AR RECOIL DISTANCE 
    Villa I.M. (1997)
    The recoil distance of 39Ar is a vital discriminant among geochronological models. Direct measurement of recoil is possible by studying 39Ar implantation in SiO2 glass from a KCl crystal, and comparing one such glass ...
  • GEOCHRONOLOGY: LINKING THE ISOTOPIC RECORD WITH PETROLOGY AND TEXTURES - AN INTRODUCTION 
    Vance D.; Müller W.; Villa I.M. (2003)
    One of the key aims of geochronology, and the subject of the papers in this Special Publication, is the linkage of isotopic ages to petrological and textural information. A close link between the two types of information ...
  • IN PURSUIT OF THE 40K BRANCHING RATIOS: K-CA AND 39AR-40AR DATING OF GEM SILICATES 
    Nagler T.F.; Villa I.M. (2000)
    This paper presents combined 39Ar-40Ar and K-Ca analyses on gem quality, K-rich silicates: a muscovite and a sanidine, both from pegmatites. We attempted to directly determine the 40K branching ratio by comparing the ...
  • RADIOGENIC ISOTOPES IN FLUID INCLUSIONS 
    Villa I.M. (2001)
    Radiogenic isotopes studied in fluid inclusions are still a limited field, with great potential for expansion as analytical techniques improve. The main limitation for Sr, Ar and He isotope work is the very small number ...
  • SINGLE MINERAL DATING BY THE PB-PB STEP-LEACHING METHOD: ASSESSING THE MECHANISMS 
    Frei R.; Villa I.M.; Nagler T.F.; Kramers J.D.; Przybylowicz W.J.; Prozesky V.M.; Hofmann B.A.; Kamber B.S. (1997)
    Stepwise Pb-Pb leaching (PbSL) has been successfully used to date rock-forming silicates directly linked to metamorphic reactions defining a PT path. The two features of PbSL are an increase of precision and a control on ...