Certified Reference Material: Geochemical Soil and Till Reference Materials
Printable version of the certificate (PDF, 247 Kb)
First Issued: November 1995
Version: November 1995
TILL-1, TILL-2, TILL-3 and TILL-4 were collected and characterized in cooperation with the Mineral Resources Division, Minerals and Continental Geoscience Branch, Geological Survey of Canada.
TILL-1 was collected 25 kilometres north-west of Lanark, Ontario; TILL-3 was collected 8 kilometres east of Cobalt, Ontario. These two soil samples were collected from the combined B and C horizons. The two till samples (TILL-2 and TILL-4) were collected near Scission's Brook, New Brunswick. At this location, extensive trenching had been done by the mining company who owned the property in order to expose the till. The company had obtained preliminary analyses of till samples collected at various sites within the trenched areas. These analyses were used as guidelines to sampling. No effort was made to collect any particular horizon. In order to augment the molybdenum levels in TILL-4, a small quantity of a molybdenite-bearing soil was collected near an old test pit. All sampling was done by shovelling.
These four materials, two soils and two tills, complete a series of reference samples of surficial materials which also includes the lake and stream sediment materials, LKSD-1, LKSD-2, LKSD-3, LKSD-4, STSD-1, STSD-2, STSD-3 and STSD-4, which are already available.
Like the sediment series, the TILL samples are characterised for major element oxides, total elements as well as elements from partial extractions. The partial extractions are concentrated hydrochloride - concentrated nitric acids and dilute hydrochloric-dilute nitric acids. In addition, informational data from a single source are provided for a number of elements derived by EPA digestions 3050 and 3051.
TILL-1, TILL-2, TILL-3 and TILL-4 are intended for quality control in chemical analysis.
Instructions for use
TILL samples should be used “as is” without drying. The contents of the bottle should be thoroughly mixed before taking samples.
Method of preparation
In each case, the collected material was spread to a depth of 7.5 to 10 cm over a polyethylene sheet and allowed to dry for several weeks at room temperature. When dry, each sample was sieved through an 80-mesh (177 µm) screen. The +80 mesh fraction was discarded. The -80-mesh fraction was ball milled and sieved through a 200-mesh screen (74 µm). The oversize material from this sieving was retained, ball milled and sieved a second time through the 200-mesh screen. At this point, any oversize fraction (plus-200 mesh) was discarded. The two minus-200-mesh fractions were combined and tumbled as a single batch in a conical blender for eight hours. Each material was bottled in 100-g units.
A method described by Lynch (1) was employed for homogeneity testing. No evidence of inhomogeneity was found.
TILL-1, TILL-2, TILL-3 and TILL-4 were characterised by an interlaboratory analysis program involving thirty-one laboratories. The provisional values for these soil and till reference materials were assigned from the average of data after a two-step trimming method described by Lynch (1).
The Canadian Certified Reference Materials Project has prepared these reference materials and statistically evaluated the analytical data of the interlaboratory certification program to the best of its ability. The purchaser, by receipt hereof, releases and indemnifies the Canadian Certified Reference Materials Project from and against all liability and costs arising out of the use of these materials and information.
(1) J.J. Lynch (1990). "Provisional elemental values for eight new geochemical lake sediment and stream sediment reference materials LKSD-1, LKSD-2, LKSD-3, LKSD-4, STSD-1, STSD-2, STSD-3 and STSD-4", Geostandards Newsletter, 14: 153-167.
|TILL-1||31F||Joe Lake, Ontario|
|TILL-2||21C||5 km West Scisson's Brook,
|TILL-3||31M||O'Brien Mine, near Cobalt, Ontario|
|TILL-4||21C||Scisson's Brook, New Brunswick|
|31G||Molybdenite Occurrence near
|LOI (500°C) %||6.3||6.8||3.6||4.4|
APPENDIX for CCRMP Reference Materials LKSD, STSD, and TILL
Explanation of Extraction Methods
The provisional values for the lake, stream and till reference materials (LKSD, STSD and TILL) were determined from the results of numerous laboratories involved in geochemical exploration using their existing routine methods. Two main types of methods were used.
The first type can be termed total methods wherein the complete amount of a particular element is determined. One subgroup of these total methods involves the sample being analyzed without pretreatment i.e., instrumental neutron activation and powder x ray diffraction. Another subgroup of total methods includes pretreatments such as a multi acid dissolution with hydrofluoric acid, or fusions followed by, for example, an instrumental finish. This second group of methods may be used to determine the total concentration of numerous elements, but losses of some other elements may occur.
A second type of techniques involves a partial dissolution or extraction of the elements using different combinations of acids at varying strengths. The laboratories that submitted data did not follow established protocols with regards to either the types or amounts of acid utilized. However, two main subgroups of partial extraction or partial dissolution techniques were chosen. The first of these involves the use of both diluted nitric and hydrochloric acids i.e., 2 mL of nitric acid, 1 mL of hydrochloric acid and 5 mL of water; or 3 mL, 2 mL and 1 mL of each component, respectively; or 3 mL, 1 mL and 4 mL of each component, respectively. The second subgroup involves the use of varying amounts of these two acids without the addition of any water i.e., 3 mL of hydrochloric acid plus 1 mL of nitric acid, or 3 mL of nitric acid plus 1 mL of hydrochloric acid. For both of these two subgroups, the sample and acid mixture were heated from 2 to 4 hours at 95°C to 100°C, cooled, diluted to volume and analyzed.
FOR FURTHER INFORMATION
The certification report is available upon request to :
Ottawa, ON, K1A 0G1
E-mail: Contact CCRMP
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