The problem of dating quartz 1: Spectroscopic ionoluminescence of dose dependence

Abstract

A suite of quartz samples of different provenances, irradiation, thermal and depositional histories were analysed using spectroscopic ionoluminescence (IL) to investigate variations in emission spectra as a function of cumulative radiation dosing. Protons were selected for implantation to mimic the effect of natural radiation over geological timescales. All samples exhibited depletion in the UV-violet emission (3.2-3.4 eV) with increasing cumulative dose, whilst the red emission (1.8-1.9 eV) increased. A power-law relationship exists between the two emissions. It is inferred that the luminescence emission of quartz is indicative of its radiation history, and spectral analyses could be used to determine the utility of different quartz samples for optically stimulated luminescence dating (OSL) where the detection range is limited to 3.4-4.6 eV. KeywordsSpectroscopic ionoluminescence, implantation, protons, quartz, optically stimulated luminescence dating. AbbreviationsIonoluminescence (IL), Ultra-violet (UV), Optically Stimulated Luminescence (OSL) IntroductionOSL is used as a radiation dosimeter method within Quaternary geochronology, archaeology and retrospective accident dosimetry. Of the materials used for OSL studies, quartz is usually preferred (Aitken, 1998;Huntley et al., 1985). In addition, quartz has a range of industrial applications, which has rendered it the focus of intense research both into its physical and chemical properties, and its emission spectroscopy (see Götze, 2009; Krbetschek et al., 1997 for reviews). Numerous OSL dating applications to sediments of different ages (e.g. Ballarini et al., 2003;Pawley et al., 2008), provenances (e.g. Preusser et al., 2006) and depositional environments (e.g. Thrasher et al., 2009;Wallinga, 2002) have been made. However, despite the development of the single-aliquot regenerative dose protocol (Murray and Wintle, 2000), it is currently not possible to date all quartz using OSL. This is often due to quartz's highly variable OSL quantum efficiency (QE). The controls over quartz OSL QE remain unclear but have been linked to geological provenance (Götze et al., 2004;Rink et al., 1993;Westaway, 2009), irradiation (Rink, 1994, transport and thermal histories (Pietsch et al., 2008;Preusser et al., 2006). However quartz with the same irradiation, source and depositional histories often exhibit highly variable emission intensities McFee and Tite, 1998).The light emitted by quartz most commonly comprises bands in the UV-blue and red/IR (Krbetschek et al., 1997). Risø readers, the most widely used OSL instrumentation, stimulate the quartz with diodes at 470±20 nm (2.6 eV) and measure the response through Hoya U340 filters . The transparency of these filters lies between 3.4 and 4.6 eV and only a part of the UV-blue emission band is monitored. The remainder of the emission (below 3.4 eV and above 4.6 eV) is unmeasured in conventional OSL but may contain significant dosimetry or geological provenance information.Ionoluminescence (IL, also known as ion beam lumin...

Response of cathodoluminescence of alkali feldspar to He+ ion implantation and electron irradiation

“…3). King et al (2011) ] 0 defect due to trapping of electron holes derived from the Na + migration at the latter defect, leading to an increase in the blue emission intensity with elevated radiation doses. The Al-O --Al/Ti defect center in feldspar is composed of electron hole trapped at Löwenstein bridges and therefore produced by Na + migration during ion implantation as well as electron irradiation (Kayama et al in submitted).…”

“…CL spectroscopy and microscopy provide valuable information on the existence and distribution of defects and trace elements in minerals with a spatial resolution of a few micrometers. According to Stevens-Kalceff et al (2000) and King et al (2011), He + ion implantation and electron irradiation significantly affect the CL properties of minerals as change of CL is activated by impurity and radiation-induced defect centers. CL analysis allow us to estimate their radiation effects on the mineral grains with high spatial resolution.…”

“…CL analysis allow us to estimate their radiation effects on the mineral grains with high spatial resolution. Recently, CL measurements on ion-implanted and electron irradiated quartz and albite have enabled interpretation of radiation effects, including observation of micrometer-sized radiation halos produced by α particles and estimation of the α and β radiation doses as geodosimetry (Owen, 1988;Komuro et al, 2002;Okumura et al, 2008;Krickl et al, 2008;Kayama et al, 2011a;Kayama et al, 2011b;King et al, 2011). Although great scientific interest exists concerning CL of radiation-induced quartz and albite, very few such investigations have been carried out for alkali feldspars up to now.…”

Cathodoluminescence of synthetic zircon implanted by He⁺ ion

“…Therefore, CL emissions in zircon are attributable to two-types of radiation-induced and intrinsic defects in addition to impurity centers. Recently, luminescent features of radiation damages by simulating the α and β particles in natural and/or synthetic minerals such as quartz, feldspar and zircon have been characterized by a spectroscopic method to assign individual emission centers (e.g., Finch et al, 2004;Okumura et al, 2008;Kayama et al, 2011;Tsuchiya et al, 2014), which suggests an evaluation of dose dependence on luminescence intensity related to radiation-induced defects (King et al, 2011;Kayama et al, 2014). Furthermore, a process of metamictization in radioactive minerals (e.g., zircon) has been estimated by luminescence methods for ionimplanted samples as a simulation of radiation-induced damage on minerals (e.g., Weber et al, 1994;Lian et al, 2003;Ewing et al, 2003;Finch et al, 2004;Nasdala et al, 2011).…”

Annealing effects on cathodoluminescence of zircon

“…Recent interests focus on the CL of radiation-damaged minerals such as quartz, feldspar and zircon to characterize the radiation effects of alpha and beta particles (Finch et al, 2004;Okumura et al, 2008;Tsuchiya et al, 2014), to visualize radiation halo produced by alpha radiation (Komuro et al, 2002;Nasdala et al, 2011) and to evaluate a correlation of CL intensity with radiation dose (King et al, 2011;Kayama et al, 2014). These investigations have been eventually conducted to apply CL of minerals for geodosimetry as well as geochronometry, especially using zircon as a radioactive mineral commonly contained in igneous, metamorphic and sedimentary rocks.…”