Seymour Island La Meseta High-Res Stable Isotopes

The data are stable oxygen and carbon isotopic ratios from macrofossils in the
La Meseta Formation (Eocene) of Seymour Island. Taxa include naticid
gastropods, brachiopods, and most importantly the bivalves Cucullaea and
Eurhomalea. Specimens were collected within a well-resolved stratigraphy from
multiple localities within stratigraphic horizons. Shells were sectioned,
polished, and sampled with a Merchantek (New Wave) MicroMill. 'Bulk' samples
are sample paths drilled across a number of growth increments, avoiding cracks
or other areas that appear to be altered. The bulk-sample dataset represents
907 analyses from 187 shells collected at 54 localities distributed within 27
stratigraphic horizons throughout the formation. An additional 288 samples
were collected during high-resolution analysis of 2 specimens of Cucullaea and
2 of Eurhomalea. These microsamples were collected along adjacent
growth-band-parallel paths and covered up to 16 years of life history.

In addition to light stable isotopes, we analyzed strontium isotope ratios of
43 bivalves from throughout the section.