Determination of rare earth and refractory trace element abundances in early solar system objects by ion microprobe |
| |
Authors: | S Sahijpal K K Marhas J N Goswami |
| |
Institution: | (1) Department of Physics, Panjab University, 160 014 Chandigarh, India;(2) Physical Research Laboratory, Navrangpura, 380 009 Ahmedabad, India;(3) Present address: Max-Planck Institut fur Chemie, Cosmochemistry Division, 55020 Mainz, Germany |
| |
Abstract: | Experimental and analytical procedures devised for measurement of rare earth element (REE) abundances using a secondary ion
mass spectrometer (ion microprobe) are described. This approach is more versatile than the conventional techniques such as
neutron activation analysis and isotope dilution mass spectrometry by virtue of its high spatial resolution that allows determination
of REE abundances in small domains (10-20 micron) within individual mineral phases. The ion microprobe measurements are performed
at a low mass-resolving power adopting the energy-filtering technique (Zinner and Crozaz 1986) for removal and suppression
of unresolved complex molecular interferences in the REE masses of interest. Synthetic standards are used for determining
various instrument specific parameters needed in the data deconvolution procedure adopted for obtaining REE abundances. Results
obtained from analysis of standards show that our ion microprobe may be used for determining REE abundances down to ppm range
with uncertainties of ∼ 10 to 15%. Abundances of rare earth and several other refractory trace elements in a set of early
solar system objects isolated from two primitive carbonaceous chondrites were determined using the procedures devised by us.
The results suggest that some of these objects could be high temperature nebular condensates, while others are products of
melting and recrystallization of precursor nebular solids in a high temperature environment. |
| |
Keywords: | Rare earth element ion microprobe solar nebula hibonite carbonaceous chondrite |
本文献已被 SpringerLink 等数据库收录! |
|