No you cannot use ostracods for absolute dating. They can be used for relative dating, however. Ostracods are not the best group to use for this since they are often provincial, and can display diachronism. However, if there is a local scheme for your region then a relative age may be determined. They are much better used for palaeoenvironmental studies since one of the main controls on their distribution is salinity. Better groups for relative dating are planktonic foraminifera or nannoplankton. If you require absolute dates then radiometric methods are essential. 

Dear Ian

Thank you for your explanation, I have evaporite formations continental and which contain ostracodes, they surely indicate the aquatic environment. What I would like is to use the carbonates (of the skeleton) for absolute dating is there a technique for it?

I don't know, absolute dating is not my field. I have never thought of doing this with my material as all the carbonate in my ostracods is re-crystallised and therefore worthless for such studies. Do you have any clay intercalations in your evaporites? These would be prime sites for radiometric techniques.

Dear Ian

The rate of clay in sediment is not more than 2%. the mineralogical composition in general is gypsum>>> oxides, quartz, and clay.

Hi,

Have you considered dating your sediments by cosmogenic radionuclides such as 26Al and 10Be (e.g., attached paper)?

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Thank you Simona