So I've been reading up on articles on how to carbon-date samples. The common problem seems to be the contamination of non carbonated material and how to remove materials that would affect the result of the carbon-dating procedure. I'm going to date coral skeletal material, however I will need 20 g of samples the is pre-washed and has already received pre-treatment before dating. ( I will not be using the AMS method for carbon-dating)

These are the main issues I've realized so far:

1. Will multi-species samples be good for carbon-dating or will it affect the result too hard and not produce good results? (multi-species samples means that from the same depth I will add multiple fragments from different species and treat them together as one sample)

2. I will have to crush the sample to a specific grain size. This is to get a homogenized sample and to be able to remove trapped sediment particles that would affect the dating result. Which size fraction would be good to use? Now we are getting combined to the third issue.

3. How should I seperate the CaCO3 material from the rest after I crushed it to a specific size?3 The easiest way so far what I've understood would be to seperate them on their density dependant scale. Two articles (Susanne Heier-Nielsen et al. 1995 & Feyling-Hanssen, R. W. et al. 1971) used CCl4 to "concentrate" their Foraminifera shells. They do not however explain how the material is concentrated. I do however assume that the shells containing mainly CaCO3 material float up and were collected from the surface layer and then washed with DIW? Could the same chemical possibly be used on crushed coral material to float the CaCO3 material from sediment residue?

4. As my coral samples are not too big and are very restricted to old fragment, an acid etching would remove a lot of sample weight. Is this step extremely crucial or can I possibly skip it to save my sample size?

5. Should I treat the samples with H2O2 before or after crushing the material, and before or after the CCl4 treatment to remove organic carbon from the sample?

Thank you all for your answers in advance!

Ref:

Radiocarbon Dating of Shells and Foraminifera from the Skagen Core, Denmark: Evidence of Reworking

Susanne Heier-Nielsen, Keld Conradsen, Jan Heinemeier, K. L. Knudsen, H. L. Nielsen, Niels Rud and Á. E. Sveinbjörnsdóttir

Radiocarbon / Volume 37 / Issue 02 / January 1995, pp 119 - 130

FEYLING-HANSSEN, R. W-, JØRGENSEN, J. A., KNUDSEN, K. L. & ANDERSEN,

A.-L. L.: Late Quaternary Foraminifera from Vendsyssel,

Denmark and Sandnes, Norway. Bull. geol. Soc. Denmark, vol. 21,

pp. 67-317. Copenhagen, December, 15th, 1971.