Bulk sedimentary nitrogen isotopes and nitrogen content of ODP Site 202-1242

The bulk sedimentary nitrogen isotopic measurements and relative contribution of nitrogen were analysed in ODP Site 202-1242 (7º51.352'N, 83º36.418'W, 1364 meters water depth) located off Costa Rica, in the East Equatorial Pacific. A selection of samples between 84 and 125 meters composite depth representing the interval between 720 and 1040 ka were dried (45ºC), ground and homogenised using a zircon ball mil. About 20 mg of sample were measured for their nitrogen isotopic composition by using an Elemental Analyzer FlashEA 1112 coupled to a ThemoFinningan MAT 253 Isotope Mass Spectrometer. The nitrogen content of the sample was measured using a micro-elemental analyser Fisons Carlo Erba EA1108.