International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2569

Full Length Research Paper

Rb-Sr and U-Pb age dating of granite rocks by inductively coupled plasma mass spectrometry

J. Hefne, O. Aldayel, M. A. Amr, O. Alharbi
Institute of Atomic Energy Research, King Abdulaziz City for Science and Technology, P.O. Box 6086 Riyadh11442, Kingdom of Saudi Arabia.
Email: [email protected]

  •  Accepted: 11 December 2006
  •  Published: 31 January 2008

Abstract

Inductively coupled plasma-mass spectrometry (ICP-MS) was used as alternative to thermal ionization mass spectrometer (TIMS) for age dating of granite samples originating from different magmatic volcanic rock formations on the Arabian shield. Cation exchange chromatography was used to avoid isobaric overlap of 87Rb with87Sr and 204Hg with 204Pb ions signals to the largest possible extent, while mathematical correction was applied to correct for the remaining interference. Sr was separated from its matrix using a crown ether-Eichrom's Sr resin. Pb separated from its matrix by developing a method using a crown ether-Eichrom's Sr resin.  The accuracy of the method developed was evaluated by means of isotopic analysis of strontium carbonate SRM-987 and common lead SRM-981 isotopic standards from NIST. Precisions of 87Sr/86Sr and 206Pb/204Pb isotope ratios measurements are < 0.1% and 0.3% (1), respectively. Overall, this case study shows the merits of ICP-MS for exploratory age determinations and studies of 87Sr/86Sr and 206Pb/204Pb isotope ratios which can differentiate between magmatic origin of granite.

 

Key words: Age dating, ICP-MS, granite, U-Pb, Rb-Sr.