Citation:

2006PA001297

Name: (Table 1) Nd isotope ratios of ODP Leg 208 samples
Published: 2007
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

We present new Nd isotope records from Walvis Ridge Ocean Drilling Program (ODP) sites 1262–1264 (southeastern Atlantic) spanning the past 24 Ma to investigate the Neogene evolution of Atlantic thermohaline circulation. The new data indicate that deepwater epsilon-Nd(t) values from ODP Site 1262 decrease from -11.0 at 10.6 Ma to -12.5 by 7.3 Ma. This decrease parallels the Nd isotope trends contained in Fe-Mn crust records from the northwestern Atlantic; however, the shift at ODP Site 1262 (4755 m water depth) occurred up to ~6 Ma earlier than the corresponding changes in crust records from the Atlantic and earlier than any Atlantic site shallower than 2700 m paleowater depth. Recent interpretations of the rapid decrease in Fe-Mn crust Nd epsilon-Nd(t)ss values invoke changes in weathering inputs to the Labrador Sea region rather than a fundamental change in deepwater convection in the Labrador Sea. However, the new evidence for significant depth stratification of the Nd isotope signal in the southeastern Atlantic between 10.6 and 7.3 Ma suggests that the onset of deepwater convection in the Labrador Sea may have played a role in the deepwater decrease in Nd isotopic composition. Climatic conditions during the middle to late Miocene likely favored an increase in the importance of glacially induced mechanical weathering, while at the same time promoting deep convection in the Labrador Sea.

Project(s):

Ocean Drilling Program (ODP)

Coverage:

Median Latitude: -28.083837 * Median Longitude: 2.400663 * South-bound Latitude: -28.532830 * West-bound Longitude: 1.577000 * North-bound Latitude: -27.186000 * East-bound Longitude: 2.845510

Date/Time Start: 2003-03-24T13:00:00 * Date/Time End: 2003-04-06T21:55:00

Minimum DEPTH, sediment/rock: 18.09 m * Maximum DEPTH, sediment/rock: 251.87 m

Event(s):

208-1262A * Latitude: -27.186000 * Longitude: 1.577000 * Date/Time Start: 2003-03-24T13:00:00 * Date/Time End: 2003-03-26T12:40:00 * Elevation: -4759.0 m * Penetration: 161.5 m * Recovery: 163.53 m * Location: Walvis Ridge, Southeast Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 17 cores; 161.5 m cored; 0 m drilled; 101.3 % recovery

208-1263A * Latitude: -28.532830 * Longitude: 2.779480 * Date/Time Start: 2003-03-29T15:15:00 * Date/Time End: 2003-04-02T01:25:00 * Elevation: -2717.1 m * Penetration: 345.6 m * Recovery: 295.78 m * Location: Walvis Ridge, Southeast Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 40 cores; 345.6 m cored; 0 m drilled; 85.6 % recovery

208-1264A * Latitude: -28.532680 * Longitude: 2.845510 * Date/Time Start: 2003-04-05T13:10:00 * Date/Time End: 2003-04-06T21:55:00 * Elevation: -2507.0 m * Penetration: 280.7 m * Recovery: 270.71 m * Location: Walvis Ridge, Southeast Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 30 cores; 280.7 m cored; 0 m drilled; 96.4 % recovery

Comment:

DEPTH, sediment/rock is given in mcd.

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	Event label	Event
2	DEPTH, sediment/rock	Depth sed	m		Geocode
3	AGE	Age	ka BP		Geocode
4	Neodymium-143/Neodymium-144 ratio	143Nd/144Nd		Thomas, Deborah J
5	Neodymium-143/Neodymium-144 ratio, error	143Nd/144Nd e	±	Thomas, Deborah J
6	ε-Neodymium (T)	ε-Nd(T)		Thomas, Deborah J
7	ε-Neodymium, error	ε-Nd e	±	Thomas, Deborah J

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

192 data points

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