Publication Date:
2023-02-24
Description:
This study presents a new alkenone-derived Sea Surface Temperature (SST) record and d18ONoelaerhabdaceae data of the 2-5 µm carbonate fractions from the IODP site U1338 located in the Eastern Equatorial Pacific (EEP), over the Miocene-Pliocene. Our data and those available from other sites of the same area show the establishment of a cold tongue during the early Pliocene (4.4 - 3.6 Ma). SST and d18ONoelaerhabdaceae time-series indicate periods of significant salinity variations. Comparison with the d18Obenthic curve from sediment cores of the Equatorial Pacific Ocean allow us to distinguish between global changes and local surface salinity variations in the EEP. Ice sheet growth and evaporation-precipitation are then discussed as possible drivers of such changes, as well as the role of Central American and the Indonesian seaway restriction. Our data suggest a shallowing of the thermocline in the EEP, between 6.8 and 6 Ma, and its shoaling between 4.8 and 4.0 Ma, suggesting the appearance of the cold tongue (Steph et al., 2010). The Pliocene climate transition would therefore not be primarily driven by Northern hemisphere glaciation.
Keywords:
321-U1338; AGE; Alkenone, unsaturation index UK'37; Calculated from C37 alkenones (Prahl & Wakeham, 1987); Calculated from UK'37 (Müller et al, 1998); Calculated from UK37 (Conte et al., 2006); COMPCORE; Composite Core; DEPTH, sediment/rock; Exp321; Gas chromatography - Mass spectrometry (GC-MS); Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; Isotope ratio mass spectrometry; Joides Resolution; n-Alkane C37; Pacific Equatorial Age Transect II / Juan de Fuca; Sample code/label; Sea surface temperature; δ18O, carbonate
Type:
Dataset
Format:
text/tab-separated-values, 877 data points
Permalink
