.Samples for the oxygen
isotopic analysis were collected from the top 42 mbsf of Hole 994C at 10-cm
intervals using a 2-cm3 plastic tube. The samples were desegregated
in an ultrasonic bath and washed through a 63-µm sieve. More than 25 specimens
of Globigerinoides sacculifer and Globigerinoides ruber larger
than 250 µm size (mostly between 250 and 425 µm for G. sacculifer and
between 250 and 355 µm for G. ruber) were hand picked for the isotopic
analyses. The foraminiferal samples were reacted with 100% H3PO4
at 60.0ºC, and the oxygen isotopic ratio of the evolved gas was measured with a
Finnigan MAT 251 mass spectrometer. The isotopic values are expressed in per
million differences from the Peedee belemnite (PDB) standard. The precision of
the oxygen isotopic measurement is better than ±0.04.
