Submitting Samples for Analysis
Producing a 210Pb dating profile requires information from the surface to bottom profile of the core. Therefore, you must submit: the surface sample, 1 cm, 2 cm and a couple of deep samples from near the bottom of the core, with the remaining 7-11 intervals spaced as an exponential depth sequence to the bottom interval. If you are only interested in the top 10-20 cm of your sediment core but you want to have a chronological date for each interval, you must submit intervals deeper than 20 cm in order for us to perform the necessary calculations for your analysis. We typically need 12-16 intervals to run a valid dating model. Always consult with us to help determine which samples to submit for analysis. All samples should be freeze-dried, and homogenous when shipped to us.
In order to perform an accurate analysis, Chronos Scientific requests the following points be considered when submitting samples for analysis.
1. Samples of at least 100 milligrams (0.1 gram) DRY weight are preferred for the sections between 0 to 10 cm and samples of at least 500 milligrams (0.5 gram) are needed for deeper samples. If you do not have this much sample, please contact us to discuss. Smaller samples can be used (e.g. as little as 10 mg), however, the precision of the results may suffer and you should consult with us before submitting small samples.
2. Samples must be aliquots from homogenized sections of the core. Large pieces of extraneous material (e.g. pieces of wood, rocks, etc.) should be removed prior to preparing the samples for 210Pb analysis.
3. Samples should ideally be freeze-dried and pulverized to pass through a screen with about 100 mesh size. This aids in the digestion of the sediment.
4. Samples cannot be oven dried, subjected to high temperature combustion or leaching. The Pb and Po isotopes can be volatilized from the samples at temperatures in excess of 150°C.
5. Ideally, 12 to 16 sections of a sediment core must be analyzed in order to produce the dating profile.
6. All samples should be freeze-dried when shipped to us. Samples should be packed in small plastic vials or in small bags and shipped in a padded manila envelope.
Declare the contents of your shipment as “crushed rock, no commercial value”.
Our shipping address will be on the sample submission sheet.
Please use a courier service and keep track of your parcel, Chronos Scientific will not do this for you.
Please request a copy of our Sample Submission Sheet by emailing: Chronos.Scientific.Inc@gmail.com
Samples that contain high industrial concentrations of known lethal metals and chemicals have to be stated and brought to our attention to ensure the safety of our staff.
Samples from previously dredged water bodies, and heavily contaminated industrial ponds and canals will not be accepted for analysis.