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Researchers may submit sediment samples to LacCore for pollen processing, either for counting slides or for AMS radiocarbon dates.
The goal in preparing sediment samples for pollen analysis is to remove as much non-pollen material from the sample as possible in order to concentrate the chemically-resistant pollen grains. Success makes counting the pollen simpler, more accurate, and less time consuming. Processed samples are returned to the requester in silicone oil or glycerol for counting slides.
Sediment samples (usually 1.0cc, sampled volumetrically or by mass) are placed in 15mL plastic centrifuge tubes and are treated sequentially, as shown in the flow chart below, with centrifuging and water rinses between each of the steps to clear the sediment of the treatment solution. Repeated rinses between some steps are used to remove fine particles from the sample and sample checks are used to determine if any step needs to be repeated.
LacCore Pollen Processing Summary (PDF, 78KB)
Samples processed for AMS dates are processed differently than samples for counting, since no carbon-containing chemicals can be used. Successful processing removes non-pollen material, especially other organic material, to concentrate pollen grains for dating. Most samples are suitable for dating after processing. In some cases the there may be too much non-pollen organic matter (e.g., soil material, cellulose, algae, fungal spores) remaining that would skew the dates. Smear slides are prepared to check sample quality and sent to the requester, or for a fee, can be evaluated by LacCore staff. AMS samples can be sent to a dating facility, such as the Center for Accelerator Mass Spectrometry (CAMS, Lawrence Livermore National Laboratory), or returned to the requester in acidified water.
Sediment samples (usually 4-5cc) are placed in pre-burned 40 mL glass centrifuge tubes and treated sequentially, as shown in the flow chart below, with centrifuging and water rinses between each of the steps to clear the sediment of the treatment solution. Repeated rinses between some steps are used to remove fine clay particles from the sample and sample checks are used to determine if any step needs to be repeated. Our procedure does not remove all siliciclastic material from the sample.
AMS Pollen Preparation Procedure (PDF, 86KB)
For questions, contact Jessica Heck or Amy Myrbo. This information and more detail can be found in our Pollen Preparation SOP (PDF, 510KB). To submit samples for processing please fill out our customer setup form and analysis request form (and associated Excel spreadsheet). When we receive those forms we will contact you about processing your samples.