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The derivation of 40 Ar/ 39 Ar age spectra of single grains of hornblende and biotite by laser step‐heating
Author(s) -
Layer Paul W.,
Hall Chris M.,
York Derek
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i007p00757
Subject(s) - hornblende , biotite , spectral line , analytical chemistry (journal) , mineralogy , materials science , geology , chemistry , physics , composite material , quartz , chromatography , astronomy
We present the first examples of 40 Ar/ 39 Ar age spectra for hornblende and biotite derived by the laser step‐heating of individual grains. It is straightforward to use a continuous laser to produce detailed (>20 steps), reproducible and precise age spectra in this way. An infra‐red microscope is used to monitor the sample temperature changes so that a judicious heating schedule can be chosen. Such a system can be readily automated. The biotite spectra shown exhibit large age differences (∼60 m.y.) between co‐existing flakes differing in mass by a factor of ∼70.