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Investigation of trace-element distribution in detrital quartz by Electron Paramagnetic Resonance (EPR).
Paramagnetic defects in natural, irradiated (2 kGy, 60Co, 295 K) and etched (40% HF, 30 min, 295 K) samples of quartz grains (grain size < 0.16 mm) from quartz-sand deposits in Weferlingen, Haltern and Frechen (Germany) were investigated by EPR at 9.5 GHz and at 20, 70, and 295 K.
In all samples [AlO4]0, [TiO4/Li+]0, [TiO4/H+]0, [TiO4]-, and Fe3+ paramagnetic centres were detected.
These differences in quartz composition were confirmed by cathodoluminescence microscopy. Etching of quartz samples with hydrofluoric acid (ca. 30% loss of mass) followed by further EPR measurement revealed that Al centres generally show more or less homogeneous distribution pattern, whereas no Fe-centres were left in quartz after etching. This indicates that Fe centres are concentrated in the outer rim of the quartz grains.
Authors:Götze, Jens and Plötze, Michael
Index Terms:clastic sediments; quartz; trace-elements; cathodoluminescence; Clay; ClayGroup
Further Information:Date published: 1997