Investigation of trace-element distribution in detrital quartz by Electron Paramagnetic Resonance (EPR)

Abstract

Paramagnetic defects in natural, irradiated (2 kGy, 60 CO, 295 K) and etched (40% HF, 30 min, 295 K) sampies 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 sampies [AI04jO, [TiOJLi+jO, [Ti041H+jO, [Ti04j-, and Fe3+ paramagnetic centres were detected. Generally, y-irradiation caused a transformation of diamagnetic precursor centres into these paramagnetic centres, resulting in an increase of the EPR intensity of up to five times. Sampies from Weferlingen have similar trace-element contents and show only minor differences in the abundance of paramagnetic centres. In contrast, the abundance of paramagnetic centres in quartz from the different deposits may differ significantly, especially Fe3+, [AI04jO and [Ti04/Li+jO centres in the y-irradiated quartz sampIes. The high concentrations of [AI04jO and [Ti04/Li+jO centres in the Weferlingen quartz sampies reflect higher amounts of igneous quartz than in the other deposits investigated. These differences in quartz composition were confirmed by cathodoluminescence microscopy. Etching of quartz sampIes with hydrofluoric acid (ca. 30% loss of mass) followed by further EPR measurement revealed that AI centres generally show a 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.

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

“…One 13 signal is intense and broad and can be assigned to interacting spins, the other less intense and sharper signal is due to localized paramagnetic species. 33 In both cases the signal of quartz dust is no more visible. Conversely, the typical signal of quartz are still present in the non milled mixture of 1% carbon and quartz (curve d).…”

Trace element incorporation into quartz: A combined study by ICP-MS, electron spin resonance, cathodoluminescence, capillary ion analysis, and gas chromatography

“…In general, the pegmatite quartz samples show different center distribution from that of quartz from igneous and metamorphic rocks (Plötze, 1995;Götze and Plötze, 1997). No relationship could be detected between the concentration of paramagnetic centers and coloration of the samples.…”

“…Because of the widespread occurrence of quartz in igneous, metamorphic and sedimentary rocks, several attempts have been made to use trace elements for genetic interpretations (e.g., Bambauer, 1961;Dennen, 1964Dennen, , 1966Dennen, , 1967Walenczak, 1969;Lyakhovich, 1972;Suttner and Leininger, 1972;Hallbauer, 1992;Heynke et al, 1992;Götze and Lewis, 1994;Götze and Plötze, 1997;Monecke et al, 1999Monecke et al, , 2002aGötze and Zimmerle, 2000;Larsen et al, 2000;Poutivcev et al, 2001;Müller et al, 2003).…”

The Chemistry of Quartz in Granitic Pegmatites of Southern Norway: Petrogenetic and Economic Implications

“…However, comparatively little of this type of work has been carried out on the chemistry of pegmatite quartz. The limited number of publications is in contrast to the abundant studies dealing with trace elements of hydrothermal (e.g., Rusk et al 2006Rusk et al , 2008Rusk et al , 2011Rusk, 2012Rusk, , 2014Tanner et al, 2013;Maydagán et al, 2015), volcanic (e.g., Watt et al, 1997;Wark et al, 2007;Audétat, 2013), plutonic (e.g., Müller et al, 2000Müller et al, , 2010bWiebe et al, 2007;Jacamon and Larsen, 2009;Breiter et al, 2013), metamorphic (e.g., Van den Kerkhof et al, 2004;Spear and Wark, 2009;Kidder et al, 2013), and sedimentary quartz (e.g., Götze and Plötze, 1997;Götze, 2012;Götte et al, 2013;Müller and Knies, 2013).…”