GSNI Data Catalogue
The Tellus regional stream sediment survey of Northern Ireland
Stream sediment from western Northern Ireland were collected by British Geological Survey (BGS) between 1994 and 1996. Stream sampling over eastern counties was undertaken by the GSNI and the BGS under the Tellus survey in 2005 and 2006.
2908 stream sediment samples were collected during the summers of 1994 to 1996 by the BGS and a further 2966 in 2005/6 by the Tellus survey. Where possible, sites were situated on first or second-order streams. The combined surveys produced an average sampling density of one site per 2.4 km².
As far as possible, samples were collected from active sediment, upstream of any potential source of contamination, such as habitation, industrial activity or any road or track crossing. Samples were collected by pairs of samplers, usually university students. The sampling and data recording procedures were standardised before the main survey. Sampling teams were changed daily to reduce the possibility of sampling bias.
The sediment sample was collected after removal of the oxidised surface material and was wet-screened on site using a method devised by B A Toms (Department of Chemistry, University of Birmingham). This method uses a minimum of water to collect the fraction of sediment finer than 150 µm. Approximately 100 g of material was collected in a Kraft™ paper bag. A heavy-mineral concentrate was obtained at each site by screening the stream sediment through a 2 mm sieve and panning 2–3 kg of this sieved material using the method described by Leake and Aucott (1973).
In the 1994/6 survey, stream sediment samples were freeze-dried and then ground to <50 µm at a field laboratory. During the Tellus field campaign, 2005/6, samples were air-dried prior to dispatch in batches of 100 to an interim storage facility. Further air-drying was completed at the store to a level that would allow samples to be packaged for onward transport to the BGS analytical laboratory. On arrival at the laboratory samples were checked against shipping lists prior to assigning laboratory batch numbers in the BGS UKAS Quality Assurance System. If necessary, the dried Tellus sediment samples were disaggregated by hand in a mortar and pestle. Tellus sediment samples were freeze-dried under reduced pressure within a pre-set temperature range of -30°C to 30°C for a minimum of 24 hours. Transposition of sample numbers and cross contamination of samples were prevented by preparing each sample individually.
The data are described in Young, Mike; Donald, Alex, eds. 2013 A guide to the Tellus data. Belfast, UK, Geological Survey of Northern Ireland, 233pp. available for free download from: http://nora.nerc.ac.uk/509171/
Stream Sediments Fire Assay
Stream sediment and S soils were analysed by fire assay for gold, palladium and platinum. The 1994/6 stream sediment samples were analysed in early 2002 at Acme Analytical Laboratories Ltd. (Vancouver), who also analysed the Tellus stream sediments. SGS Laboratories analysed the Tellus S soils. For both sample types 10 g sub-samples of milled material were prepared and dispatched to the analytical contractors by the BGS laboratory. A standard lead fire assay process was completed on samples in both laboratories. Soil samples were fired for 60 minutes with a flux mixture containing lead oxide (litharge) in a gas furnace at 1050ºC ±100ºC. Sediment samples were fired for 40 minutes. Silver was added in order to alloy the precious metals and produce a bead at the end of the cupellation process. On completion of the firing the resulting lead button was separated from the borosilicate slag and subsequently heated in a MnO cupel for 1 hour. This removed the lead and produced a silver bead containing Au, Pt and Pd (and Rh).
For the soil analysis the bead was digested in 0.5 mL of 1:1 nitric acid and 0.5 mL of hydrochloric acid and then diluted to 5 mL with water. For sediments the bead was digested with 1 mL of hot nitric acid (HNO3) and then 10 mL of hydrochloric acid (HCl). In both laboratories a portion of the digested silver bead was aspirated into the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) where the concentrations of Au, Pd and Pt were determined against calibration standards. A semi-quantitative analysis of rhodium was obtained in stream sediment samples. Soil samples were analysed on a Perkin Elmer Sciex Elan 9000 ICP-MS Spectrometer and sediment samples on a Perkin Elmer Elan 6000 ICP-MS Spectrometer. Quoted detection limits for soil and sediment analysis are shown in Table 3. For soils the calibration curve consisted of four points: blank, 10, 25 and 50 µg/L for each of gold, palladium and platinum in solution. An independent check solution at 10 µg/mL was analysed after the calibration, a ±10 % tolerance had to be met before analysis commenced.
Stream Sediments: Boron analysis by ICP-MS
Boron analyses of stream sediments, contemporaneous with the fire assay, were performed at Acme Analytical Laboratories Ltd. (Vancouver) as this element cannot be determined by XRF. A 0.10 g sub-sample of milled sediment was weighed into a zirconium crucible and mixed with 1.5 g Na2O2 and 0.5 g NaOH. Analysis was completed by ICP-MS using a single spectrometer (ICP13) in the case of Tellus samples. The quoted detection limit was 2 mg/kg. Internal laboratory quality control was completed in accordance with the procedures outlined for the Acme Laboratories fire assay analysis. Quality control of 1994/6 samples was monitored using internal standard LIB-10. For Tellus samples quality control was monitored using internal standards C3, FA-100S and LIBF200
The Tellus survey was funded by the Department of Enterprise, Trade and Investment (DETI), now the Department for the Economy (DfE) in Northern Ireland and the INTERREG IVA programme of the European Union (EU) Regional Development Fund.
Simple
- Date (Creation)
- 2007
- Citation identifier
- https://gsni-data.bgs.ac.uk/geonetwork/srv/api/records/3d5d7b86-e0ca-4942-8c28-17aa5ae95a85
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Organisation name Individual name Electronic mail address Role Geological Survey of Northern Ireland
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- Not planned
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Organisation name Individual name Electronic mail address Role Geological Survey of Northern Ireland
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GEMET - INSPIRE themes, version 1.0
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Geology
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Tellus
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- INSPIRE: no limitations
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- Provided under the Open Government Licence: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ We request that you acknowledge that the resource contains Geological Survey of Northern Ireland materials provided under the Open Government Licence.
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- Begin date
- 2005-01-01
- End date
- 2006-12-31
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Information on survey, processing and data conditioning can be found in the following reports:
A Guide to the Tellus Data edited by Young, M.E. and Donald, A.W. can be downloaded at http://nora.nerc.ac.uk/id/eprint/509171/
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The Tellus geochemical surveys of Northern Ireland
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- 2023-11-08T08:32:20
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ISO 19115:2003/19139
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1.0
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Organisation name Individual name Electronic mail address Role Geological Survey of Northern Ireland
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