Publication Date:
1991-03-01
Description:
Multiple stratigraphies of subtropical South Atlantic cores reveal significant stratigraphic discrepancies between the nannofossil and the foraminiferal carbonates. Variations in the stratigraphic signals carried in the nannofossil-dominated 38 μm fraction were measured with detailed stratigraphies of δ18O, δ13C, 14C, grain size, percentage carbonate, percentage aragonite, and taxonomic composition across the last deglaciation in INMD box core 111 No. 9. Three other cores (INMD box cores 113 and 115, and V 22–174), also from the shallow flanks of the mid-Atlantic ridge in the South Atlantic (10°–17° S), contain similar stratigraphies indicating that these cores represent regional patterns. The onset of the deglacial δ18O shift in foraminiferal carbonate occurs 6 to 20 cm deeper than the δ18O shift in the nannofossil fraction. Nineteen accelerator mass spectrometer 14C dates of various fractions (355 μm, and G. ruber) from INMD Box 111 show that the components within an individual core slice may differ by up to 4900 14C years. Twelve traditional 14C dates (determined by beta counting) of the 〉38 and
Print ISSN:
0033-5894
Electronic ISSN:
1096-0287
Topics:
Geography
,
Geosciences
Permalink