LITHOGEOCHEMISTRY
The most aggressive fusion technique employs a lithium metaborate/ tetraborate fusion for whole rock analysis.
Actlabs performs fusions using a robotic system, which provides a fast fusion of the highest quality in the industry. The resulting molten bead is rapidly digested in a weak nitric acid solution. The fusion ensures that the entire sample is dissolved. It is only with this attack that major oxides including SiO2, refractory minerals (i.e. zircon, sphene, monazite, chromite, gahnite, etc.), REE and other high field strength elements are put into solution. High sulphide-bearing rocks may require different treatment but can still be adequately analyzed. Analysis is by ICP-OES and ICP-MS. Quality of data is exceptional and can be used for the most exacting applications. Values on internal replicates and standards are provided, as well as REE chondrite plots. Eu determinations are semi-quantitative in samples having extremely high Ba concentrations (> 5 %). Although intended primarily for un-mineralized samples, mineralized samples can also be analyzed; however, data may be semi-quantitative for chalcophile elements (Ag, As, Bi, Co, Cu, Mo, Ni, Pb, Sb, Sn, W and Zn).
Samples are prepared and analyzed in a batch system. Each batch contains a method reagent blank, certified reference material and 6% replicates. Samples are mixed with a flux of lithium metaborate and lithium tetraborate and fused in an induction furnace. The molten melt is immediately poured into a solution of 5% nitric acid containing an internal standard, and mixed continuously until completely dissolved. The samples are run for major oxides and selected trace elements (4B) on an ICP. Calibration is performed using 14 prepared USGS and CANMET certified reference materials. One of the 14 standards is used during the analysis for every group of ten samples.
Totals should be between 98.5% and 101%. If results come out lower, samples are scanned for base metals. Low reported totals may indicate sulphate being present or other elements like Li which won’t normally be scanned for. Samples with low totals however are automatically re-fused and reanalyzed.
Fusion ICP
| Oxide | Detection Limit (%) |
|---|---|
| Al2O3 | 0.01 |
| CaO | 0.01 |
| Fe2O3 | 0.01 |
| K2O | 0.01 |
| MgO | 0.01 |
| MnO | 0.001 |
| Na2O | 0.01 |
| P2O5 | 0.01 |
| SiO2 | 0.01 |
| TiO2 | 0.001 |
| Loss on Ignition | 0.01 |
Trace Elements
| Element | Detection Limit (ppm) |
|---|---|
| Ba | 2 |
| Be | 1 |
| Sc | 1 |
| Sr | 2 |
| V | 5 |
| Y | 1 |
| Zr | 2 |
Code 4B options:
Code 4B1 : recommended for accurate levels of base metals (Cu, Pb, Zn, Ni and Ag) .
Code 4B-INAA : recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm.
Samples fused under code 4B2 are diluted and analyzed by ICP-MS. Three blanks and five controls (three before the sample group and two after) are analyzed per group of samples. Duplicates are fused and analyzed every 15 samples. Instrument is recalibrated every 40 samples.
Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Hf | 0.2 | 1,000 |
| Ho | 0.1 | 1,000 |
| In | 0.2 | 200 |
| La | 0.1 | 2,000 |
| Lu | 0.04 | 1,000 |
| Mo | 2 | 100 |
| Nb | 1 | 1,000 |
| Nd | 0.1 | 2,000 |
| Ni | 20 | 10,000 |
| Pb | 5 | 10,000 |
| Pr | 0.5 | 1,000 |
| Rb | 2 | 1,000 |
| Sb | 0.5 | 200 |
| Sm | 0.1 | 1,000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Sn | 1 | 1,000 |
| Sr | 2 | 10,000 |
| Ta | 0.1 | 500 |
| Tb | 0.1 | 1,000 |
| Th | 0.1 | 2,000 |
| Tl | 0.1 | 1,000 |
| Tm | 0.05 | 1,000 |
| U | 0.1 | 1,000 |
| V | 5 | 5,000 |
| W | 1 | 5,000 |
| Y | 1 | 1,000 |
| Yb | 0.1 | 1,000 |
| Zn | 30 | 10,000 |
| Zr | 5 | 10,000 |
| Element | W2 | Cert. |
|---|---|---|
| Y | 21 | 24 |
| Zr | 99 | 94 |
| Nb | 7.5 | 7.9 |
| Mo | 0.7 | 0.6 |
| Ag | <0.5 | 0.05 |
| In | <0.2 | - |
| Sn | <0.5 | - |
| Sb | 0.78 | 0.79 |
| Cs | 0.95 | 0.99 |
| Ba | 164 | 182 |
| La | 11.3 | 11.4 |
| Element | W2 | Cert. |
|---|---|---|
| Yb | 2.06 | 20.5 |
| Lu | 0.33 | 0.33 |
| Hf | 2.64 | 2.56 |
| Ta | 0.5 | 0.5 |
| W | <0.2 | 0.3 |
| Tl | 0.1 | 0.2 |
| Pb | 8 | 9.3 |
| Bi | <0.05 | 0.03 |
| Th | 2.3 | 2.5 |
| U | 0.49 | 0.53 |
4B2-STD options:
4B2-STDQuant: Although intended primarily for unmineralized samples, mineralized samples can be analyzed. However data may be semiquantitative for chalcophile elements (Ag, As, Bi, Co, Cu, Mo, Ni, Pb, Sb, Sn, W and Zn). A 1 g sample is digested with aqua regia and diluted to 250 ml volumetrically. Appropriate international reference materials for the metals of interest are digested at the same time. The samples and standards are analyzed on a Varian Vista 735 or a Thermo ICAP 6500 ICP.
Code 4B1 : recommended for accurate levels of base metals (Cu, Pb, Zn, Ni and Ag) .
Code 4B-INAA : recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm
Code 5D: recommended for Sn >50 ppm.
Samples fused under code 4B2 are diluted and analyzed by ICP-MS. Three blanks and five controls (three before the sample group and two after) are analyzed per group of samples. Duplicates are fused and analyzed every 15 samples. Instrument is recalibrated every 40 samples.
Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Ag | 0.5 | 100 |
| As | 5 | 2,000 |
| Ba | 3 | 300,000 |
| Bi | 0.1 | 2,000 |
| Ce | 0.05 | 3,000 |
| Co | 1 | 1,000 |
| Cr | 20 | 10,000 |
| Cs | 0.1 | 1,000 |
| Cu | 10 | 10,000 |
| Dy | 0.01 | 1,000 |
| Er | 0.01 | 1,000 |
| Eu | 0.005 | 1,000 |
| Ga | 1 | 500 |
| Gd | 0.01 | 1,000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Hf | 0.1 | 1,000 |
| Ho | 0.01 | 1,000 |
| In | 0.1 | 200 |
| La | 0.05 | 2,000 |
| Lu | 0.002 | 1,000 |
| Mo | 2 | 100 |
| Nb | 0.2 | 1,000 |
| Nd | 0.05 | 2,000 |
| Ni | 20 | 10,000 |
| Pb | 5 | 10,000 |
| Pr | 0.01 | 1,000 |
| Sb | 0.2 | 200 |
| Sm | 0.01 | 1,000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Sn | 1 | 1,000 |
| Sr | 2 | 10,000 |
| Ta | 0.01 | 500 |
| Tb | 0.01 | 1,000 |
| Th | 0.05 | 2,000 |
| Tl | 0.05 | 1,000 |
| Tm | 0.005 | 1,000 |
| U | 0.01 | 1,000 |
| V | 5 | 5,000 |
| W | 0.5 | 5,000 |
| Y | 0.5 | 5,000 |
| Yb | 0.01 | 1,000 |
| Zn | 30 | 10,000 |
| Zr | 1 | 10,000 |
| Element | W2 | Cert. |
|---|---|---|
| V | 256 | 262 |
| Cr | 90 | 93 |
| Co | 44 | 44 |
| Ni | 67 | 70 |
| Cu | 105 | 103 |
| Zn | 72 | 77 |
| Ga | 18 | 20 |
| Ge | 2 | 1 |
| As | <5 | 1.24 |
| Rb | 20 | 20 |
| Sr | 193 | 194 |
| Element | W2 | Cert. |
|---|---|---|
| Y | 21 | 24 |
| Zr | 99 | 94 |
| Nb | 7.5 | 7.9 |
| Mo | 0.7 | 0.6 |
| Ag | <0.5 | 0.05 |
| In | <0.2 | - |
| Sn | <0.5 | - |
| Sb | 0.78 | 0.79 |
| Cs | 0.95 | 0.99 |
| Ba | 164 | 182 |
| La | 11.3 | 11.4 |
| Element | W2 | Cert. |
|---|---|---|
| Ce | 24 | 24 |
| Pr | 2.5 | 5.9? |
| Nd | 14 | 14 |
| Sm | 3.38 | 3.25 |
| Eu | 1.1 | 1.1 |
| Gd | 3.5 | 3.6 |
| Tb | 0.62 | 0.63 |
| Dy | 3.8 | 3.8 |
| Ho | 0.76 | 0.76 |
| Er | 2.3 | 2.5 |
| Tm | 0.32 | 0.38 |
| Element | W2 | Cert. |
|---|---|---|
| Yb | 2.06 | 20.5 |
| Lu | 0.33 | 0.33 |
| Hf | 2.64 | 2.56 |
| Ta | 0.5 | 0.5 |
| W | <0.2 | 0.3 |
| Tl | 0.1 | 0.2 |
| Pb | 8 | 9.3 |
| Bi | <0.05 | 0.03 |
| Th | 2.3 | 2.5 |
| U | 0.49 | 0.53 |
4B2-Research options:
4B2-ResearchQuant: Although intended primarily for unmineralized samples, mineralized samples can be analyzed. However data may be semiquantitative for chalcophile elements (Ag, As, Bi, Co, Cu, Mo, Ni, Pb, Sb, Sn, W and Zn).
Code 4B1 : recommended for accurate levels of base metals (Cu, Pb, Zn, Ni and Ag) .
Code 4B-INAA : recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm.
Code 5D: recommended for Sn >50 ppm.
A combination of packages 4B (lithium metaborate/tetraborate fusion ICP whole rock) and 4B2 (trace element ICP-MS)
Fusion ICP
| Oxide | Detection LImit (%) |
|---|---|
| Al2O3 | 0.01 |
| CaO | 0.01 |
| Fe2O3 | 0.01 |
| K2O | 0.01 |
| MgO | 0.01 |
| MnO | 0.001 |
| Na2O | 0.01 |
| P2O5 | 0.01 |
| SiO2 | 0.01 |
| TiO2 | 0.001 |
| Loss on Ignition | 0.01 |
Trace Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit | Reported By |
|---|---|---|---|
| Ag | 0.5 | 100 | ICP/MS |
| As | 5 | 2,000 | ICP/MS |
| Ba | 2 | 500,000 | ICP |
| Be | 1 | - | ICP |
| Bi | 0.4 | 2,000 | ICP/MS |
| Ce | 0.1 | 3,000 | ICP/MS |
| Co | 1 | 1,000 | ICP/MS |
| Cr | 20 | 10,000 | ICP/MS |
| Cs | 0.5 | 1,000 | ICP/MS |
| Cu | 10 | 10,000 | ICP/MS |
| Dy | 0.1 | 1,000 | ICP/MS |
| Er | 0.1 | 1,000 | ICP/MS |
| Eu | 0.05 | 1,000 | ICP/MS |
| Ga | 1 | 500 | ICP/MS |
| Gd | 0.1 | 1,000 | ICP/MS |
| Ge | 1 | 500 | ICP/MS |
| Hf | 0.2 | 1,000 | ICP/MS |
| Ho | 0.1 | 1,000 | ICP/MS |
| In | 0.2 | 200 | ICP/MS |
| La | 0.1 | 2,000 | ICP/MS |
| Lu | 0.01 | 1,000 | ICP/MS |
| Mo | 2 | 100 | ICP/MS |
| Nb | 1 | 1,000 | ICP/MS |
| Element | Detection Limit | Upper Limit | Reported By |
|---|---|---|---|
| Nd | 0.1 | 2,000 | ICP/MS |
| Ni | 20 | 10,000 | ICP/MS |
| Pb | 5 | 10,000 | ICP/MS |
| Pr | 0.05 | 1,000 | ICP/MS |
| Rb | 2 | 1,000 | ICP/MS |
| Sb | 0.5 | 200 | ICP/MS |
| Sc | 1 | - | ICP |
| Sm | 0.1 | 1,000 | ICP/MS |
| Sn | 1 | 1,000 | ICP/MS |
| Sr | 2 | 10,000 | ICP |
| Ta | 0.1 | 500 | ICP/MS |
| Tb | 0.1 | 1,000 | ICP/MS |
| Th | 0.1 | 2,000 | ICP/MS |
| Tl | 0.1 | 1,000 | ICP/MS |
| Tm | 0.05 | 1,000 | ICP/MS |
| U | 0.1 | 1,000 | ICP/MS |
| V | 5 | 10,000 | ICP |
| W | 1 | 5,000 | ICP/MS |
| Y | 1 | 10,000 | ICP |
| Yb | 0.1 | 1,000 | ICP/MS |
| Zn | 30 | 10,000 | ICP/MS |
| Zr | 2 | 10,000 | ICP |
4Litho options:
4LithoQuant: Although intended primarily for unmineralized samples, mineralized samples can be analyzed. However data may be semiquantitative for chalcophile elements (Ag, As, Bi, Co, Cu, Mo, Ni, Pb, Sb, Sn, W and Zn).
Code 4B1 : recommended for accurate levels of base metals (Cu, Pb, Zn, Ni and Ag) .
Code 4B-INAA : recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm.
Code 5D: recommended for Sn >50 ppm.
A combination of packages 4B (lithium metaborate/tetraborate fusion ICP whole rock) and 4B2 (trace element ICP-MS).
Fusion ICP
| Oxide | Detection Limit (%) |
|---|---|
| SiO2 | 0.01 |
| Al2O3 | 0.01 |
| Fe2O3 | 0.01 |
| MgO | 0.01 |
| MnO | 0.001 |
| CaO | 0.01 |
| TiO2 | 0.001 |
| Na2O | 0.01 |
| K2O | 0.01 |
| P2O5 | 0.01 |
| Loss on Ignition | 0.01 |
Trace Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit | Reported By |
|---|---|---|---|
| Nd | 0.05 | 2,000 | ICP/MS |
| Ni | 20 | 10,000 | ICP/MS |
| Pb | 5 | 10,000 | ICP/MS |
| Pr | 0.01 | 1,000 | ICP/MS |
| Rb | 1 | 1,000 | ICP/MS |
| Sb | 0.2 | 200 | ICP/MS |
| Sc | 1 | - | ICP/MS |
| Sm | 0.01 | 1,000 | ICP/MS |
| Sn | 1 | 1,000 | ICP/MS |
| Sr | 2 | 10,000 | ICP |
| Ta | 0.01 | 500 | ICP/MS |
| Tb | 0.01 | 1,000 | ICP/MS |
| Th | 0.05 | 2,000 | ICP/MS |
| Tl | 0.05 | 1,000 | ICP/MS |
| Tm | 0.005 | 1,000 | ICP/MS |
| U | 0.01 | 1,000 | ICP/MS |
| V | 5 | 10,000 | ICP |
| W | 0.5 | 5,000 | ICP/MS |
| Y | 0.5 | 10,000 | ICP/MS |
| Yb | 0.01 | 1,000 | ICP/MS |
| Zn | 30 | 10,000 | ICP/MS |
| Zr | 1 | 10,000 | ICP/MS |
4Lithoresearch – Options
4LithoResearchQuant: Although intended primarily for unmineralized samples, mineralized samples can be analyzed. However data may be semiquantitative for chalcophile elements (Ag, As, Bi, Co, Cu, Mo, Ni, Pb, Sb, Sn, W and Zn).
Code 4B1 : recommended for accurate levels of base metals (Cu, Pb, Zn, Ni and Ag) .
Code 4B-INAA : recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm.
Code 5D: recommended for Sn >50 ppm.
Add-Ons:
A 0.30 g sample is digested with four acids beginning with hydrofluoric, followed by a mixture of nitric and perchloric acids, heated using precise programmer controlled heating in several ramping and holding cycles which takes the samples to dryness. After dryness is attained, samples are brought back into solution using hydrochloric acid. With this digestion certain phases may be only partially solubilized. These phases include zircon, monazite, sphene, gahnite, chromite, cassiterite, rutile and barite. Ag greater than 50 ppm and Pb greater than 5,000 ppm should be assayed as high levels may reprecipitate. Only sulphide sulfur will be solubilized.
In-lab standards (traceable to certified reference materials) or certified reference materials are used for quality control.
Samples are analyzed using an ICP.
Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Ag | 0.3 | 100 |
| Cd | 0.5 | 2,000 |
| Cu | 1 | 10,000 |
| Ni | 1 | 10,000 |
| Pb | 5 | 5,000 |
| S | 0.001% | 20% |
| Zn | 1 | 10,000 |
INAA (Instrumental Neutron Activation Analysis) is an analytical technique dependent on measuring gamma radiation induced in the sample by irradiation with neutrons. The primary source of neutrons for irradiation is usually a nuclear reactor. Each activated element emits a “fingerprint” of gamma radiation which can be measured and quantified. Routine multi-element analyses by INAA are performed on practically any material from the smallest sample which can be weighed accurately to very large samples.
A 30g aliquot, if available, is encapsulated in a polyethylene vial and irradiated along with flux wires at a thermal neutron flux of 7 x 10 12 ncm-2 s-1. After a 7-day period to allow Na-24 to decay the samples are counted on a high purity Ge detector with resolution of better than 1.7 KeV for the 1332 KeV Co-60 photopeak. Using the flux wires and control standards, the decay-corrected activities are compared to a calibration developed from multiple certified international reference materials. For values exceeding the upper limits, assays are recommended. One standard is run for every 11 samples. One blank is analyzed per work order. Duplicates are analyzed when sample material is available.
Elements and Detection Limits (ppm)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| As | 0.5 | 10,000 |
| Au | 2 ppb | 30,000 ppb |
| Br | 0.5 | 5000 |
| Ce | 3 | 10,000 |
| Co | 1 | 10,000 |
| Cr | 5 | 100,000 |
| Cs | 1 | 10,000 |
| Eu | 0.2 | 10,000 |
| Hf | 1 | 5000 |
| Ir | 5 ppb | 10,000 |
| La | 0.5 | 10,000 |
| Lu | 0.05 | 10,000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Mo | 5 | 10,000 |
| Nd | 5 | 10,000 |
| Rb | 20 | 10,000 |
| Sb | 0.2 | 10,000 |
| Sc | 0.1 | 1,000 |
| Se | 3 | 10,000 |
| Sm | 0.1 | 10,000 |
| Ta | 0.5 | 10 |
| Tb | 0.5 | 10,000 |
| Th | 0.2 | 10,000 |
| U | 0.5 | 10,000 |
| W | 1 | 10,000 |
| Yb | 0.2 | 10,000 |
Reference:
Hoffman, E.L., 1992. Instrumental Neutron Activation in Geoanalysis. Journal of Geochemical Exploration, volume 44, pp. 297-319.
For quantitative values of chalcophile elements
X-ray fluorescence (XRF) spectroscopy method is used as industry standard for the determination of the major and some trace elements. This method has a rapid turnaround time and offers one of the best levels accuracy and precision of any multi elemental geochemistry package.
To minimize the matrix effects of the samples, the heavy absorber fusion technique of Norrish and Hutton (1969, Geochim. Cosmochim. Acta, volume 33, pp. 431-453) are used for major element (oxide) analysis. Prior to fusion, the loss on ignition (LOI), which includes H2O+, CO2, S and other volatiles, can be determined from the weight loss after roasting the sample at 1000°C for 2 hours. The fusion disk is made by mixing a 0.75 g equivalent of the roasted sample with 9.75 g of a combination of lithium metaborate and lithium tetraborate with lithium bromide as a releasing agent. Samples are fused in platinum crucibles using an automated crucible fluxer and automatically poured into platinum molds for casting. Samples are analyzed on a wavelength dispersive XRF. The intensities are then measured and the concentrations are calculated against the standard G-16 provided by Dr. K. Norrish of CSIRO, Australia. Matrix corrections were done by using the oxide alpha – influence coefficients provided also by K. Norrish.
Oxides and Detection Limits (%)
Oxide Detection
Al2O3 0.01
CaO 0.01
Cr2O3 0.01
Co3O4 0.005
CuO 0.005
Fe2O3 0.01
K2O 0.01
MgO 0.01
MnO 0.005
Na2O 0.01
NiO 0.003
P2O5 0.01
SiO2 0.01
TiO2 0.01
V2O5 0.003
LOI 0.01
Samples are dried at 105°C prior to LOI or fusion as laterites can easily absorb water from air. To minimize the matrix effects of the samples, the heavy absorber fusion technique of Norrish and Hutton (1969, Geochim. Cosmochim. Acta, volume 33, pp. 431-453) is used for major element (oxide) analysis. Prior to fusion, the loss on ignition (LOI), which includes H2O+, CO2 , S and other volatiles, can be determined from the weight loss after roasting the sample at 1000°C for 2 hours. The fusion disk is made by mixing a 0.75 g or 0.19g equivalent of the roasted sample with 9.75g of a combination of lithium metaborate and lithium tetraborate with lithium bromide as a releasing agent. Samples are fused in Platinum crucibles using an automated crucible fluxer and automatically poured into platinum molds for casting. Samples are analyzed on a wavelength dispersive XRF.
The intensities are then measured and the concentrations are calculated against the Ausmon standard which adjusts the calibration. Control standards are run to verify the procedure. Matrix corrections were done by using the oxide alpha – influence coefficients provided also by K. Norrish.
Oxides and Detection Limits (%)
Oxide Detection
Al2O3 0.01
CaO 0.01
Co3O4 0.01
Cr2O3 0.01
CuO 0.005
Fe2O3 0.01
K2O 0.01
MgO 0.01
MnO 0.005
Na2O 0.01
NiO 0.003
P2O5 0.01
SiO2 0.01
TiO2 0.01
V2O5 0.003
LOI 0.01
