Mid-Pliocene deep-sea bottom water temperatures based on ostracode Mg/Ca ratios

We studied magnesium:calcium (Mg/Ca) ratios in shells of the deep-sea ostracode genus Krithe from a short interval in the middle Pliocene between 3.29 and 2.97 Ma using deep-sea drilling sites in the North and South Atlantic in order to estimate bottom water temperatures (BWT) during a period of cli...

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Bibliographic Details
Main Authors: Cronin, Thomas M, Dowsett, Harry J, Dwyer, Gary S, Baker, Paul A, Chandler, Mark A
Format: Dataset
Language:English
Published: PANGAEA 2005
Subjects:
108-658A
108-659A
108-661A
114-704
68-502C
81-552A
90-588
94-607
94-610A
Canarias Sea
Caribbean Sea/RIDGE
COMPCORE
Composite Core
DRILL
Drilling/drill rig
Glomar Challenger
Joides Resolution
Leg108
Leg114
Leg68
Leg81
Leg90
Leg94
North Atlantic/FLANK
North Atlantic/PLATEAU
North Atlantic/RIDGE
North Atlantic Ocean
Ocean Drilling Program
ODP
South Atlantic Ocean
South Pacific/Tasman Sea/CONT RISE
Southern Ocean
Pacific
Dwyer
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.684703
https://doi.org/10.1594/PANGAEA.684703
Description
Summary:We studied magnesium:calcium (Mg/Ca) ratios in shells of the deep-sea ostracode genus Krithe from a short interval in the middle Pliocene between 3.29 and 2.97 Ma using deep-sea drilling sites in the North and South Atlantic in order to estimate bottom water temperatures (BWT) during a period of climatic warmth. Results from DSDP and ODP Sites 552A, 610A, 607, 658A, 659A, 661A and 704 for the period Ma reveal both depth and latitudinal gradients of mean Mg/Ca values. Shallower sites (552A, 610A and 607) have higher mean Mg/Ca ratios (10.3, 9.7, 10.1 mmol/mol) than deeper sites (661A, 6.3 mmol/mol), and high latitude North Atlantic sites (552A, 610 and 607) have higher Mg/Ca ratios than low latitude (658A: 9.8 mmol/mol, 659A: 7.7 mmol/mol, 661A: 6.3 mmol/mol) and Southern Ocean (704: 8.0 mmol/mol) sites. Converting Mg/Ca ratios into estimated temperatures using the calibration of Dwyer et al. (1995) [Dwyer, G.S., Cronin, T.M., Baker, P.A., Raymo, M.E., Buzas, J.S., Corrège, T., 1995. North Atlantic deepwater temperature change during late Pliocene and late Quaternary climatic cycles. Science 270, 1347–1351] suggests that mean middle Pliocene bottom water temperatures at the study sites in the deep Atlantic were about the same as modern temperatures. However, brief pulses of elevated BWT occurred several times between 3.29 and 2.97 Ma in both the North and South Atlantic Ocean suggesting short-term changes in deep ocean circulation.

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