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Luminescence Characteristics of Intraplate-Derived Olivines


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Fig 1

Olivine structure. A) Silicon tetrahedra (blue spheres are oxygen) are laterally joined by Fe or Mg (large green spheres) to the next tetrahedral. Modified from Nesse (2012). B) M1 and M2 are octahedral sites. Note that site M1 is more distorted than M2. T indicates the centre of the tetrahedron.
Olivine structure. A) Silicon tetrahedra (blue spheres are oxygen) are laterally joined by Fe or Mg (large green spheres) to the next tetrahedral. Modified from Nesse (2012). B) M1 and M2 are octahedral sites. Note that site M1 is more distorted than M2. T indicates the centre of the tetrahedron.

Fig 2

Filter and detection equipment characteristics. A) Transmission curves for all filters and B) quantum efficiencies of the Hamamatsu 9235QB (‘UV PMT’) and Hamamatsu H7421-40 Photon Counting Head (‘Red PMT’). PMT, photomultiplier tubes.
Filter and detection equipment characteristics. A) Transmission curves for all filters and B) quantum efficiencies of the Hamamatsu 9235QB (‘UV PMT’) and Hamamatsu H7421-40 Photon Counting Head (‘Red PMT’). PMT, photomultiplier tubes.

Fig 3

TL characterisation protocols: Protocols A and B. The flow chart defines the sequence of steps for a single aliquot, with white boxes indicating steps that only occur once and grey indicating repeated steps. The repeating portions of the method are indicated with an arrow and an integer indicating the number of repetitions. For each repetition, any changing experimental parameters are indicated in brackets (<>). For example, the steps in Protocol A are carried out seven times total, and each time a different filter pack is used for the TL detection. TL, thermoluminescence.
TL characterisation protocols: Protocols A and B. The flow chart defines the sequence of steps for a single aliquot, with white boxes indicating steps that only occur once and grey indicating repeated steps. The repeating portions of the method are indicated with an arrow and an integer indicating the number of repetitions. For each repetition, any changing experimental parameters are indicated in brackets (<>). For example, the steps in Protocol A are carried out seven times total, and each time a different filter pack is used for the TL detection. TL, thermoluminescence.

Fig 4

Photostimulated luminescence characterisation protocols: Protocols C–G. The flow chart defines the sequence of steps for a single aliquot (see Fig. 3 for more details). Protocol E involves two sets of repeated steps. The parameters that are changed in each set of repetitions are indicated by the enclosing punctuation, <> and {}.
Photostimulated luminescence characterisation protocols: Protocols C–G. The flow chart defines the sequence of steps for a single aliquot (see Fig. 3 for more details). Protocol E involves two sets of repeated steps. The parameters that are changed in each set of repetitions are indicated by the enclosing punctuation, <> and {}.

Fig 5

Analysed thin sections: A) LZ2, B) LZ4-X, C) LZ4-B, D) VRE-42, E) E-1. Photographs were taken using a binocular microscope (magnification ×4) under cross-polarised light. Examples of olivine (Ol), clinopyroxene (cpx) and orthopyroxene (opx) are identified in the images. Note that the black areas in (c) are vesicles.
Analysed thin sections: A) LZ2, B) LZ4-X, C) LZ4-B, D) VRE-42, E) E-1. Photographs were taken using a binocular microscope (magnification ×4) under cross-polarised light. Examples of olivine (Ol), clinopyroxene (cpx) and orthopyroxene (opx) are identified in the images. Note that the black areas in (c) are vesicles.

Fig 6

Glow curve data is presented for low-dose TL characterization. Background subtracted and normalised glow curves are plotted over a heatmap and contour lines, indicating the temperature and wavelength of detected peaks. Heatmap and contours are intended for visualization; these have been estimated via interpolation of the measured glow curves and median filtering (window = 4 °C × 40 nm). Contours are drawn at intervals of 25,000 counts for samples E-1, LZ4-B and LZ4-X, and 10,000 counts for HB, VRE-42 and LZ2. Curve data has not been plotted at temperatures greater than 350 °C and 300 °C for yellow and red emissions, respectively, due to the high thermal background. Note also that luminescence count scales cover a larger range for E-1 and LZ4-X. TL, thermoluminescence.
Glow curve data is presented for low-dose TL characterization. Background subtracted and normalised glow curves are plotted over a heatmap and contour lines, indicating the temperature and wavelength of detected peaks. Heatmap and contours are intended for visualization; these have been estimated via interpolation of the measured glow curves and median filtering (window = 4 °C × 40 nm). Contours are drawn at intervals of 25,000 counts for samples E-1, LZ4-B and LZ4-X, and 10,000 counts for HB, VRE-42 and LZ2. Curve data has not been plotted at temperatures greater than 350 °C and 300 °C for yellow and red emissions, respectively, due to the high thermal background. Note also that luminescence count scales cover a larger range for E-1 and LZ4-X. TL, thermoluminescence.

Fig 7

Background corrected low- and high-dose glow curves compared for samples A) E-1, B) HB and C) LZ4-B.
Background corrected low- and high-dose glow curves compared for samples A) E-1, B) HB and C) LZ4-B.

Fig 8

Remnant olivine natural glow curves (410 nm): grains were exposed to standard office lighting conditions for several hours during preparation. A typical signal used for background subtraction is also shown.
Remnant olivine natural glow curves (410 nm): grains were exposed to standard office lighting conditions for several hours during preparation. A typical signal used for background subtraction is also shown.

Fig 9

PSL properties of olivine samples. A) Net PSL signals as a proportion of the total net signal emitted by grains from each sample. Signal proportion and total signal are calculated for each sample from the average of all measured aliquots and each repeated cycle. Only reliably detected signals are included (see text). Decay curves from all measured aliquots are presented for B) BSL380, C) YSL380, and D) IRSL410 measurements (75 °C main plot, post-IR 150 °C inset). IR, infrared; PSL, photostimulated luminescence.
PSL properties of olivine samples. A) Net PSL signals as a proportion of the total net signal emitted by grains from each sample. Signal proportion and total signal are calculated for each sample from the average of all measured aliquots and each repeated cycle. Only reliably detected signals are included (see text). Decay curves from all measured aliquots are presented for B) BSL380, C) YSL380, and D) IRSL410 measurements (75 °C main plot, post-IR 150 °C inset). IR, infrared; PSL, photostimulated luminescence.

Fig 10

Proportion of TL (%) bleached by blue, yellow or IR stimulation for samples A) E-1, B) HB, C) LZ2 and D) VRE-42. The bleaching percentage is sometimes greater than 100 due to analytical error. Subplots for each sample correspond to emission detection wavelengths, and line colours indicate the stimulation light. For example, it is apparent that for sample E-1 blue light bleaches nearly all TL signal in the 330 nm detection window for temperatures up to ~350 °C. IR, infrared; TL, thermoluminescence.
Proportion of TL (%) bleached by blue, yellow or IR stimulation for samples A) E-1, B) HB, C) LZ2 and D) VRE-42. The bleaching percentage is sometimes greater than 100 due to analytical error. Subplots for each sample correspond to emission detection wavelengths, and line colours indicate the stimulation light. For example, it is apparent that for sample E-1 blue light bleaches nearly all TL signal in the 330 nm detection window for temperatures up to ~350 °C. IR, infrared; TL, thermoluminescence.

Fig 11

Results of storage experiments for samples A) E-1, B) HB, C) LZ4-B, D) VRE-42. For each sample, measured aliquots are distinguished by marker shape (circle and diamond). White-filled aliquots indicate that an aliquot failed at least one recycling ratio test. Test dose sensitivity change is shown in the inset boxes for E-1 and HB. Note that the sensitivity patterns do not correlate with ‘outlier’ intensity measurements. Calculated g-values (tc = two days) are also given (see text for details).
Results of storage experiments for samples A) E-1, B) HB, C) LZ4-B, D) VRE-42. For each sample, measured aliquots are distinguished by marker shape (circle and diamond). White-filled aliquots indicate that an aliquot failed at least one recycling ratio test. Test dose sensitivity change is shown in the inset boxes for E-1 and HB. Note that the sensitivity patterns do not correlate with ‘outlier’ intensity measurements. Calculated g-values (tc = two days) are also given (see text for details).

Fig 12

Short-shine recuperation as a percentage of initial PSL intensity (Step 6, Protocol E) measured for all olivine samples: A) BSL380, B) YSL380, C) IRSL410 75 °C. PSL, photostimulated luminescence.
Short-shine recuperation as a percentage of initial PSL intensity (Step 6, Protocol E) measured for all olivine samples: A) BSL380, B) YSL380, C) IRSL410 75 °C. PSL, photostimulated luminescence.

Fig 13

Dose recovery experiments: measured for each sample from BSL380, YSL380, and IRSL410 75 °C emissions. Growth curves (left, data jittered to aid visibility) and decay curves (right) are shown for each stimulation/detection combination. Both the signal measured directly after the Recovery Dose and the recuperated signal (post-bleach, five days storage) decay curves are shown. Test dose sensitivity changes are also presented (inset).
Dose recovery experiments: measured for each sample from BSL380, YSL380, and IRSL410 75 °C emissions. Growth curves (left, data jittered to aid visibility) and decay curves (right) are shown for each stimulation/detection combination. Both the signal measured directly after the Recovery Dose and the recuperated signal (post-bleach, five days storage) decay curves are shown. Test dose sensitivity changes are also presented (inset).

Major oxide composition of analysed olivines (in wt%).

Sample SiO2 TiO2 Al2O3 FeO MnO MgO CaO Cr2O3 NiO Mg#
LZ2 41.34 0.01 0.02 8.18 0.12 49.84 0.04 0.02 0.41 92
LZ4-X 41.38 0.00 0.00 7.96 0.12 50.10 0.00 0.01 0.40 93
LZ4-B 39.69 0.04 0.04 13.92 0.23 45.48 0.32 0.03 0.23 87
E-1 37.97 0.04 0.04 24.26 0.68 36.47 0.47 0.01 0.06 75
HB 40.18 0.05 0.23 13.04 0.15 45.45 0.32 0.18 0.37 87
VRE-42 37.95 0.03 0.04 22.94 0.35 38.18 0.39 0.03 0.09 77

Filter and PMT details. a) Detection packs (filters + PMT) for TL emission measurement. All detection packs use a Schott KG3 (3 mm) as one of two filters; the second filter slot is variable. Transmitted flux refers to the integrated flux through each filter set as a proportion of the total possible transmission, and the calculation for N is given in the text. b) PSL filter combinations used, always detected with UV PMT. No normalization is applied.

a) TL detection packs.

Detection pack [central λ, nm] Variable filter slot Detector Transmitted flux (x10−2) Norm. factor, N (x10−2)
1 [330] AHF-BrightLine HC 340/26 Interference (5 mm) UV PMT 1.92 0.57
2 [380] Delta BP 365/50 EX-Interference (5 mm) UV PMT 3.79 1.13
3 [410] AHF Brightline HC 414 (3.5 mm) UV PMT 5.50 1.50
4 [565] AHF Brightline HC 575 (5 mm) UV PMT 3.60 0.10
5 [620] AHF ET Bandpass 620 (3.5 mm) UV PMT 6.22 0.03
6 [565] AHF Brightline HC 575 (5 mm) Red PMT 3.59 1.63
7 [620] AHF ET Bandpass 620 (3.5 mm) Red PMT 6.22 2.60

PMT, photomultiplier tubes; TL, thermoluminescence.

Dose recovery results: each row corresponds to measurements made on one aliquot. The recycling ratio and zero-dose ratios are as defined in the text. Note that aliquots were not preheated prior to the five days zero-dose measurement. The recovered dose has been normalised by the given dose (116.0 Gy).

Sample Emission Recycling ratio Zero-dose ratio (%) Normalised recovered ratio

Immediate Five days
HB BSL380 1.11 ± 0.1 0.60 ± 1.24 88.44 ± 7.60 1.05 ± 0.08
YSL380 0.97 ± 0.19 12.57 ± 5.52 0.88 ± 0.14
IRSL410 1.10 ± 0.06 3.00 ± 0.52 36.62 ± 1.80 0.97 ± 0.04
LZ4-B BSL380 0.93 ± 0.05 1.53 ± 0.57 −0.24 ± 0.56 0.93 ± 0.05
YSL380 0.95 ± 0.05 0.68 ± 0.68 0.80 ± 0.04
IRSL410 0.93 ± 0.05 2.13 ± 0.50 3.54 ± 0.48 1.02 ± 0.05
LZ4-X BSL380 0.96 ± 0.08 −7.63 ± 1.72 27.81 ± 2.81 0.84 ± 0.05
YSL380 1.00 ± 0.05 0.43 ± 0.43 0.00 0.89 ± 0.04
IRSL410 1.11 ± 0.06 3.90 ± 0.54 0.45 ± 0.45 1.01 ± 0.13
VRE-42 BSL380 1.01 ± 0.05 1.98 ± 0.47 14.52 ± 0.85 0.96 ± 0.06
IRSL410 0.97 ± 0.05 4.31 ± 0.51 0.56 ± 0.46 1.03 ± 0.06

Olivine sample details.

Location Sample Rock type Latitude Longitude
Lanzarote LZ2 Peridotite xenolith 29.009361°N 13.716361°W
Lanzarote LZ4 Basalt (B) and xenolith (X) 29.021917°N 13.711972°W
Eifel E-1 Trachy-Basalt 50.348812°N 7.187948°E
Hawaii HB Olivine sand 18.936620°N 155.646280°W
Argentina VRE-42 Basalt 35.848694°S 69.16200°W
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