Late Eocene to early Miocene ice sheet dynamics and the global carbon cycle ...

• Main Authors: Lear, Caroline H, Rosenthal, Yair, Coxall, Helen, Wilson, Paul A
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2020
• Subjects: Ocean Drilling Program ODP; Antarc*; Antarctic; Ice Sheet
• Online Access: https://dx.doi.org/10.1594/pangaea.913850; https://doi.pangaea.de/10.1594/PANGAEA.913850

Paired benthic foraminiferal trace metal and stable isotope records have been constructed from equatorial Pacific Ocean Drilling Program Site 1218. The records include the two largest abrupt (<1 Myr) increases in the Cenozoic benthic oxygen isotope record: Oi‐1 in the earliest Oligocene (∼34 Ma) and Mi‐1 in the earliest Miocene (∼23 Ma). The paired Mg/Ca and oxygen isotope records are used to calculate seawater δ18O (δw). Calculated δw suggests that a large Antarctic ice sheet formed during Oi‐1 and subsequently fluctuated throughout the Oligocene on both short (<0.5 Myr) and long (2–3 Myr) timescales, between about 50 and 100% of its maximum earliest Oligocene size. The magnitudes of these fluctuations are consistent with estimates of sea level derived from sequence stratigraphy. The transient expansion of the Antarctic ice sheet at Mi‐1 is marked in the benthic δ18O record by two positive excursions between 23.7 and 22.9 Ma, each with a duration of 200–300 kyr. Bottom water temperatures decreased by ... : When using these data please cite: Lear et al. 2004. This workbook includes both the raw isotope data and the screened data (=raw data minus a handful of fliers, that we attribute to a failing collector on the mass spec) (see text in paper for definition of "fliers“). Please note that for δ13C, in Figure 3 of the paper, a few fliers were included. Therefore to reproduce Figure 3B, the column "δ13C plotted Lear et al 04" will need to be used. In all other cases please use "δ13C screened". To reproduce Figure 3A please use "δ18O screened Lear et al 04“. ...