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Bulk sediment is widely used for radiocarbon dating, especially in cases when macrofossils are unavailable. For bulk samples, some consultation may be needed to determine whether a simple acid wash (media code “A”), AAA method, or compound specific analysis is needed, but most of the time only an acid wash is performed to give a true “bulk” signature.

Recommendations:

• Be sure to remove rootlets
• If possible, aim to select an organic-rich layer. Sandy soils generally have low %C, consider sieving to remove sand sized fractions
• Oven dry your samples before storage/shipping (60°C for 12-24 hours)
• Please provide % organic carbon if available

Ideal weight: varies, please submit 500mg (min. 100mg)

The radiocarbon age of wood or charcoal corresponds to the growth year of the tree ring. Depending on the research question, the most appropriate date will often be from either the outer tree rings or small twigs. The majority of wood samples will undergo AAA (Acid-Alkali-Acid) pre-treatment (see Crann et al. 2017 PDF, 401 KB). Our chemical pre-treatment methods (material code “AAA”) will remove post-depositional carbonates as well as humic acids. Peat can be analyzed as either selected macrofossils or as bulk material. Peat and Plant macrofossils will also undergo the standard AAA pre-treatment.

Keep in mind that aquatic environments can produce reservoir effects (I.e. freshwater reservoir in hard water regions especially in limestone catchments, or marine reservoir effects in coastal regions) in which the radiocarbon signature of the organic material may not reflect the atmospheric radiocarbon signature. If this is the case, additional information or samples may be needed to obtain an accurate calendar age. Please consult with us if you have questions.

Recommendations:

• Oven dry your samples before storage/shipping (60°C for 12-24 hours)
• Visually inspect all samples and remove any rootlets or other signs of physical contamination.
• Wood: Try to ship only dry wood and remove any bark if you can
• Charcoal: Charcoal samples should be picked out, floated, or sieved from any accompanying sediment.
• Peat and plant macrofossils: If shipping macrofossils, they must be rinsed in deionized, distilled or ultra-pure (Milli-Q) water to remove residual sediment. Bulk peat samples often contain a silty component and a vegetative component. Both can be dated separately or together. Do not ship in aluminum foil as it may degrade. We recommend isolating macrofossils with tweezers or by sieving in distilled, deionized water. Identification should be made prior to shipping.

Ideal weight: >20mg (min. 10mg)

Where year to year differences in F14C are desired, individual tree rings will undergo an α-cellulose extraction upon request. The samples undergo a series of solvent washes and bleach/acid-base washes to isolate alpha-cellulose material.

Recommendations:

• Sample tree rings in thin shavings (do not grind – will degrade in the base wash)
• Avoid glues or other products used in mounting for tree-ring counting. Please inform us if you suspect potential contamination.
• Oven dry your samples before storage/shipping (60°C for 12-24 hours)

Ideal weight: 20–40mg (min. 10mg)

Researchers sometimes request to date the humic acid (alkali-soluble) and humin (alkali insoluble) fractions of bulk sediment or peat. The general theory is that humic acids percolate downward and make radiocarbon dates appear younger. However, this is not always the case so it is important to test this method first before pursuing numerous analyses.

*CONSULTATION RECOMMENDED

Ideal weight: varies, please submit 500mg (min. 100mg)

For the analysis of bone samples, collagen is extracted (material code “B”) following a modified Longin collagen extraction method (decalcification-gelatinization, see Crann et al. 2017 PDF, 401 KB).

For teeth, the dentine is most reliable for dating as the enamel exchanges carbon with the environment. Dentine also has a higher initial collagen content. The tooth root (which is dentine) may have better collagen preservation if it was protected for some time in the bone.

Ultrafiltration (material code “BU”) may be requested. The theory is that ultrafiltration will concentrate longer intact protein molecules and can be used to remove shorter chain proteins more likely to originate from contaminants.

Collagen yield, atomic C:N, δ13C and δ15N (analyzed via EA-IRMS by our partner lab, the Jan Veizer Stable Isotope Laboratory) are reported with all bone collagen dates as a QA measure of collagen preservation and for insight on dietary and environmental factors.

Requirements:

• *Please pre-screen bone samples prior to shipping to the lab*
  Bone samples can fail to produce collagen if the collagen has been degraded or the bone has been charred. Since collagen holds the inorganic part of the bone together, the easiest way to test for suitability is to try to scrape the bone with a scalpel or snap the bone by hand. If the bone is friable and easy to scrape or snap (for the exception of small ribs or bird bones), the collagen has likely been degraded. When bones fail to produce collagen in the lab, we will try a second time. The first two failed attempts will not be charged, but we reserve the right to charge for the collagen extraction at the discretion of laboratory personnel, especially if the bone has a negligible nitrogen content (as measured in the lab).

Recommendations:

• Send clean and dry bone samples. Damp samples may contain mold which can cause deterioration of the collagen.
• If possible, select from the hard part of the bone (cortical bone); we typically avoid the spongy part which is porous and susceptible to degradation and post-death carbon exchange with the environment.

Ideal weight: 1000mg (min. 300mg)

Calcined (cremated) bones can be a viable alternative to bone collagen for radiocarbon dating in environments where bone collagen is not well preserved. Bones reach a calcined state at ~600°C, at which point all organic carbon is burned away. Calcined bone will have a white or grey-blue hue throughout, sometimes chalky white if the fire is above 600°C. For calcined bone, we target the inorganic carbon fraction. Soft crusts will be physically removed from the surface of the bone, and the sample will undergo a pretreatment of 1.5% sodium hypochlorite solution (to remove organics) followed by a 1M acetic acid treatment (to remove soluble/adsorbed carbonates); finally, the sample is converted to CO2 by acid hydrolysis.

Recommendations:

• Oven dry your samples before storage/shipping (60°C for 12-24+ hours)
• Remove any rootlets or other contaminants

Ideal weight: 2g (min. 1g)

CONSULTATION RECOMMENDED: Typically these materials undergo the AAA pretreatment, however a solvent wash may be required if consolidants, preservatives, waxes, oils or other contaminants are suspected.

Ideal weight: varies, please contact us.

Physical pre-treatment of shells involves removal of the outer layer of the shell with a hand drill or scalpel as well as chalky or recrystallized areas to isolate aragonite only. Samples may undergo a chemical pre-treatment in the lab involving the dissolution of the outermost shell in dilute HCl (material code “S”), where typically 20% by mass is removed. Very small or powdered samples will not undergo this stage of pre-treatment (material code “SN”).

Recommendations:

• It is not advised to store powdered carbonates for long periods as the large surface area exposes the sample to contamination by atmospheric CO2. If powdering the sample is necessary for sampling by drilling or powdered specific areas, powdered samples should be stored in small glass vials and shipped to the lab as soon as possible.
• Oven dry your samples before storage/shipping (60°C for 12-24 hours)

Requirements:

• If the samples are of marine origin, the client should also provide a marine reservoir correction (∆R) on the submission form appropriate to their collection site to be incorporated in the calibration of results. Please consult with us if you are uncertain of an appropriate reservoir correction for your site.
• Please note: calibration of marine samples north of 40-50° latitude is not recommended (particularly for samples older than Holocene) due to the variability in sea ice extent (see Heaton et al. 2020, and Heaton et al. 2022).

Ideal weight: 20mg (min. 10mg)

CONSULTATION REQUIRED: Particulate organic carbon filtered from water or air samples onto quartz filters. (ideally small diameter to reduce the filter blank). Filters will undergo an acid fumigation in the lab to remove any inorganic carbon, followed by combustion to purified CO2 on an elemental analyzer.

Requirements:

• Filters must be pre-ashed (500°C for min. 3 hours).
• We also require additional blank filters to quantify any filter blank (min 2-3).
• Please ensure you have filtered enough material to yield 1mgC.
• Filters should be oven dried before storage/shipping (60°C for 12-24 hours)

Ideal weight: 2mgC (min. 1mgC)

All solid organic samples must be converted to CO2, prior to graphitization and analysis. For samples that have undergone chemical pre-treatment in our lab, the cost of CO2 production is included in the total analysis fee (by material code . Combustion typically takes place on an elemental analyzer, which purifies the gas, and clean CO2 is trapped in 6mm pyrex tubes.

CONSULTATION REQUIRED: After a sample preparation laboratory has been validated  as an external laboratory (by prior testing of QA/QC standards), we can accept chemically pre-treated material for direct combustion. Consultation is required to ensure the external laboratory poses no risk of tracer contamination, and the proper pre-treatment protocols are followed. We will not accept pretreated material without QA/QC standards that have been treated alongside the unknown samples (analyzed at no charge). We can provide aliquots of standards.

Ideal weight: 1mgC (min. 0.5mgC)

At this time, all solid organic samples must be converted to CO2 and graphite prior to analysis. For samples that have undergone chemical pre-treatment in our lab, the cost of CO2 and graphite production is included in the total analysis fee (by material code).

Elemental carbon is produced from CO2 at 550–570°C in the presence of a preconditioned (reduced) Fe powder catalyst following the Bosch hydrogen-reduction reaction:

CO2 + 2H2 → C + 2H20

The 14C preparation lab is equipped with newly designed, semi-automated 10-port graphitization lines. The vacuum line, cooling assembly, ovens, and touch screen controls are supported on a single frame. The stainless steel vacuum lines were orbital welded to ensure smoother interior joints and to minimize CO2 adherence and cross contamination. The cooling assembly was designed to provide equal, uniform cooling for each reaction module to optimize water extraction during graphitization. All operations on the line are controlled with a touch screen monitor using Labview. Oven and water trap temperatures, and pressures are continuously monitored and the ovens and valves are all operated under program control, thus facilitating automation. Safety controls are programmed into the software to prevent human error, to avoid sample loss or vacuum accidents. These automation and safety features contribute to a streamlined design, making graphitization easy, safe, and operator-friendly. For more information about the semi-automated CO2 purification and graphitization equipment, please refer to St-Jean et al, 2017 (PDF 1.4 MB).

CONSULTATION REQUIRED: Please contact us if you wish to submit prepared graphite.