Objective
This project, in which research teams from Germany, France, Russia, Ukraine and Tajikistan are taking part, aims to improve and deepen understanding of a geological chronometer with growing scientific importance and obtain new geological knowledge on the basis of its application on minerals from various crustal environments. This chronometer is the uranium / fission-xenon method of dating with its advanced variant induced-xenon / fission-xenon dating, the powerful relative of the well-known 40Ar/39Ar step dating technique. Progress will be made co-operatively through developing the analytical trace amount technique by modernising equipment and methodical procedures in order to facilitate very sensititive Xe isotope measurements of high precision and accuracy.
This technique will also be used to evaluate new measurements on minerals where the behaviour of the hosting rocks during evolutionary steps of earth history is well known. Efforts will therefore be focused on minerals (mainly pitchblende, zircons) for which other chemical and isotopic information (above all chronometric data) are already available or will be supplied by the partners of this research project. Owing to the well established qualities of the uranium-lead and the samarium-neodymium methods, results obtained by these chronometers will play an important part in the evaluation of the Xe data. Technical and methodological improvements will be carried out on geological samples of current scientific interest to the partners. They will be taken from high-grade Precambrian metamorphic terrains of Antarctica or the Baltic Shield and from hydrothermal deposits of central Europe. Isotopic ages of higher resolution and significance are envisaged which will complement and expand the information hitherto derived from uranium/lead data.
Improvements to the analytical Xe isotope equipment at the Vernadsky Institute are expected. These improvements will make the instruments analytically more sensitive and less susceptible to everyday hazards, thus making a greater amount of analysis possible. The Xe/Xe work on standard materials and on well selected zircon, as well as on pitchblende samples where independently determined age data exists, will demonstrate how closely the results of the various age determinations match. Evidence will be gained as to whether Xe/Xe dates of geological disturbed pitchblends are more reliable than U-Pb data.
On the basis of the intercomparisons and intercalibrations, ideas will be developed by which the extraordinary Xe retentivity of zircon may be explained. The new age determinations, performed in Moscow, Rennes and Heidelberg, will be contributions to the geological history of the areas and structures from where the samples originate. Altogether a unique contribution to methodology and applicability of isotope geochronometry will have been made.
Topic(s)
Call for proposal
Data not availableFunding Scheme
Data not availableCoordinator
69120 Heidelberg
Germany