calcite was processed in the stable isotope labs of the Michigan University (USA) following the methods described in Gomez and Goy (2011).
VPDB is the corrected isotope delta value for 13C measured against the reference standard Vienna Pee Dee Belemnite
Soon the girls learned how to tell an ammonite, belemnite
, or crinoid from a stone.
13]C values were expressed relative to the international Pee Dee Belemnite
(PDB) standard using per mil units (Craig, 1957).
sam]) relative to that of the PeeDee Belemnite
Where there is a discrepancy between the disposition of a structure and its anatomical origins, as in tortoise shells and belemnite
guards, we classify the structure on the basis of its actual geometry, for we are here concerned with the design elements animals actually employ, rather than their strict homologies and evolutionary derivations.
12]C), of the International Reference Material Vienna Pee Dee Belemnite
It is generally accepted that the preservation conditions of calcitic belemnite
rostra, which are distinguished by their original low-magnesium calcite composition, makes them relatively stable and resistant to diagenetic alteration (Veizer, 1974; Sslen, 1989; Podhala et al.
13]C deviation from the internationally recognized standards Vienna Pee Dee Belemnite
Data were reported relative to the International Atomic Energy Agency secondary standards that have been certified relative to Vienna PeeDee Belemnite
13]C ([per thousand]) values are relative to the Pee Dee Belemnite
(PDB) Standard (Silva et al.
13]C values are reported in per mil relative to Vienna Pee Dee belemnite
standard and the reproducibility was better than [+ or -] 0.
Nitrogen is referenced to atmospheric nitrogen and carbon to the Pee Dee Belemnite
Standards used were PeeDee Belemnite
13]C foi medida em relacao ao padrao de carbono chamado de Peedee Belemnite
Carbonate (PDB) na relacao: