Attempts at estimating the amplitudes of eustatic changes for the Oligocene have been controversial. For example, a "mid" Oligocene eustatic fall of >100 m has been estimated by Exxon Production Research, versus approximately 35 m indicated by delta (super 18) O records. We address discrepancies among Oligocene eustatic estimates in two regions most sensitive to eustatic change: western equatorial Pacific (ODP Site 803D) and onshore New Jersey (ODP Legs 150X and 174AX). The delta (super 18) O records from Site 803D provide an indirect proxy for glacioeustasy. In this study, monospecific planktonic and monogeneric benthic foraminiferal samples were used, ranging in age from 34.1 to 29.5 Ma. The planktonic delta (super 18) O records covary with the benthic foraminiferal delta (super 18) O events Oil (33.5 Ma), Oi1a (32.8 Ma), Oi1b (31.7 Ma), and Oi2 (30.1 Ma). New Jersey onshore records provide a more direct proxy for relative sea level changes. From these sites, we developed a benthic foraminiferal paleoslope model for multiple time slices, providing water depth estimates. Using these water depth variations in back-stripping, we estimated eustatic changes from 34.0 to 23.0 Ma. A comparison of the Site 803 delta (super 18) O records with the eustatic estimates from New Jersey show excellent agreement. At the Oi1b delta (super 18) O event, there is a 0.5 per mil increase in the planktonic foraminiferal delta (super 18) O records. Ascribing the entire delta (super 18) O signal to ice yields a 45 m eustatic decrease. This compares well with the estimated eustatic fall of 42 m from the New Jersey data. Three other major planktonic foraminiferal delta (super 18) O increases at Oi1a, Oi1b, and Oi2 show similar correlations.

West: 160.3227 East: 160.3229 North: 2.2601 South: 2.2559

Expedition: 130

Site: 130-803

Provider: SEDIS Publication Catalogue

Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=2000-018111 (c.f. for more detailed metadata)

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