Paleo Slide Set: Climate and the Classic Maya Civilization
Example of ostracod shell, genus Candona

Once the cores are split, the sample is washed over a 63-micron sieve and shell 
specimens are picked using a binocular microscope. The oxygen isotope ratios of 
ostracods (shown here), which precipitate shells or carapaces of calcite, are 
then measured. 

Photo Credits:
David A. Hodell 
Department of Geology, University of Florida