Stable isotope ratios of foraminifera from DSDP Hole 90-588A (Table 2)

• Main Authors: Flower, Benjamin P, Kennett, James P
• Format: Dataset
• Language: English
• Published: PANGAEA 1993
• Subjects: 90-588A; AGE; Cibicidoides coryelli; δ13C; δ18O; Cibicidoides mundulus; Cibicidoides wuellerstorfi; Deep Sea Drilling Project; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Globigerinoides quadrilobatus; Globoquadrina dehiscens; Glomar Challenger; Leg90; Mass spectrometer Finnigan MAT 251; Sample code/label; South Pacific/Tasman Sea/CONT RISE; Antarctic; East Antarctic Ice Sheet; Pacific; Antarc*; Ice Sheet
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.52716; https://doi.org/10.1594/PANGAEA.52716

High-resolution stable isotopic records are presented for the epi-benthic foraminifer Cibicidoides, the inferred shallow-dwelling planktonic Globigerinoides quadrilobatus, and the inferred deep-dwelling planktonic Globoquadrina dehiscens from the middle Miocene (~16-12 Ma) of Deep Sea Drilling Project site 588A, Lord Howe Rise, southwest Pacific. High-resolution, multiple species oxygen and carbon isotopic data define the timing and character of the well-known middle Miocene climatic-oceanographic transition with a resolution comparable to Quaternary records. The benthic foraminiferal delta18O record is marked by several large fluctuations from ~16 to 14.8 Ma, followed by a series of rapid (<50 kyr) delta18O increases that suggest a new state of the ocean-climate system after 14.8 Ma. The total middle Miocene benthic oxygen isotopic increase of 1.2 per mil is largely incorporated in two steps, an increase of 0.8 per mil from 14.5 to 14.0 Ma and a second increase of 0.7 per mil from 13.45 to 12.45 Ma. Each step is comprised of a series of marked delta18O increases, indicative of rapid East Antarctic ice sheet growth and contemporaneous deepwater cooling. A strong covariance of 0.7 per mil between the benthic and deep-dwelling planktonic species from 14.5 to 14.0 Ma (including a rapid increase from 14.1 to 14.05 Ma) suggests a 0.7 per mil increase in the delta18O composition of seawater (delta18Osw) because of East Antarctic ice sheet growth. Comparison of the delta18O record of Gs. quadrilobatus suggests that surface waters warmed at this site by ~3°C from 14.1 to 13.6 Ma. Carbon isotopic time series for each species generally covary throughout the early to middle Miocene interval (~16-12 Ma), confirming that delta13C variations in this interval largely represent reservoir changes. High-resolution delta13C data allow improved resolution of the latter five of six delta13C maxima within the well-known early to middle Miocene carbon isotopic excursion (the Monterey Carbon Isotopic Excursion from 17.0 to 13.5 Ma). ...