Using SG06 Special Blend

Before use, the SG06 Special Blend needs to be thoroughly mixed using the supplied magnetic stirrer. This step is facilitated by the very similar density/specific gravity values of marker grains and medium, which also prevents centrifugal sorting from occurring.

A suitable amount of the homogeneous suspension is then added to the volume- or weight- measured sediments. Ideally, in order to obtain absolute pollen concentration measurements with sufficient precision, the number of added Palynospheres™ grains should be greater than the number of fossil pollen grains within the sample. The standard procedure for pollen extraction can then be applied without any modification.

Palynospheres™ can be used with all types of chemicals typically utilized in microfossil extraction. Ideally, the recovery rate of fossil pollen grains, as well as that of the Palynospheres™, should not vary according to the extraction methods. This, however, can be quantitatively checked by the recently proposed standard sample method for microfossils [1]. Palynospheres™ can be used for any analyses of microfossils which are of a corresponding size to the marker grains.

The absolute pollen concentration can be calculated using the following equation:

pollen concentration per unit volume: c (grains/cm3)

c = p/a × dv/g

pollen concentration per unit mass: (grains/g)

= p/m × dv/g

where p is the number of pollen counts (grains), a is the volume of sediment sample (cm3), d is the concentration of the marker grain suspension (grains/cm3), v is the added marker grain suspension volume (cm3), g is the number of marker grains counted with pollen grains (grains), and m is the sample mass (g).

When the sediment accumulation rate s (cm/yr) is known, the pollen flux N (grains/yr·cm2) can be calculated using the following equation:

N = c×s

If two sizes of marker grains mixed at a known ratio were used (which is typically the case when using SG06 Special Blend, but can also be achieved by using a customized mixture prepared by users from dry powders), then one can check whether sorting (preferential recovery of large or small pollen) occurred during sample preparation.

References:

  1. Nakagawa T, Kitagawa H, Payne R, Tarasov P, Demske D (2013) A standard sample method for controlling microfossil data precision: A proposal for higher data quality and greater opportunities for collaboration. Quaternary International 290–291: 239–244.
  2. Nakagawa T. & Kitaba, I. (2017) Black ceramic spheres as marker grains for microfossil analyses, with improved chemical, physical, and optical properties. Quaternary International 455: 166–169.

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