Citation:

PANGAEA.981262 (dataset in review)

Abstract:

The Neodymium (Nd) isotopic signature (εNd) has been widely used as a proxy to reconstruct past ocean circulation. Recently it has been increasingly questioned which archives can be reliably used to extract authigenic εNd used for the reconstruction of past ocean circulation and under which environmental conditions bottom seawater εNd are altered and the original water mass signature is overprinted. Pore waters of marine sediments are the key environment in which early diagenetic exchange processes between seawater-derived Nd and terrigenous solid phases take place. This dataset contains rare earth element and yttrium (REY) and manganese (Mn) concentrations of pore water and bottom water from the abyssal Atlantic Ocean. Pore waters are oxic (no elevated Mn) and REY pore-water concentrations are low with 10-40 pM.

Samples were collected during cruise MSM96 in 2020. Seawater samples were taken with NISKIN bottles attached to a CTD water sampling carousel. Pore waters were sampled from MUC liners and for some samples several liners were pooled to acquire sufficient volume, especially for samples for which also Nd isotopes were measured. Sediments were centrifuged and the supernatant (i.e., the pore water) and the MUC bottom water were filtered through 0.2 µm pore size by different techniques (polyethersylfone syringe filters and nuclepore membrane filters using gas pressure). Pore water and seawater was preserved by acidification to ~ pH 1.8 with concentrated ultrapure HCl. Diffusive gradients in thin films (DGTs) were deployed for 12.5 and 28.4 hours at 5°C. Membranes were cut into 1-4 cm slices, eluted with 1 M HNO3 and measured by quadrupole ICP-MS (Perkin Elmer Nexion 350x). Sample concentrations were then calculated following methods described in Zhang and Davison (1995). The different methods lead to different results and based on a comparison of concentration data and shale-normalized REY patterns, syringe filtered samples were deemed most reliable.

REY and Mn were preconcentrated offline using a seaFAST (Elemental Scientific Inc., Nebraska, USA) with a 10 mL sample loop and using a NOBIAS PA-1 resin column. Samples were spiked with 100 ppt Tm and In to monitor yields and all REY were Tm corrected at the end of the data evaluation. Correction was usually within 5-15%. Preconcentrated samples were measured on a Thermo Fisher Element HR-ICP-MS (GEOMAR, Kiel) coupled to a CETAC Aridus 2 desolvating nebulizer for increased sensitivity and decreased oxide formation.

Related to:

Zhang, Hao; Davison, William (1995): Performance Characteristics of Diffusion Gradients in Thin Films for the in Situ Measurement of Trace Metals in Aqueous Solution. Analytical Chemistry, 67(19), 3391-3400, https://doi.org/10.1021/ac00115a005

Funding:

German Research Foundation (DFG), grant/award no. 458637508: Early diagenetic alteration of rare earth element and yttrium (REY) signals in marine sediments and impact on the use of REY as tracers in past and present marine environments

Coverage:

Median Latitude: 43.143590 * Median Longitude: -16.063333 * South-bound Latitude: 38.096950 * West-bound Longitude: -17.692750 * North-bound Latitude: 48.072750 * East-bound Longitude: -14.498330

Date/Time Start: 2020-10-13T09:37:19 * Date/Time End: 2020-11-02T10:06:17

Minimum Elevation: -5483.3 m * Maximum Elevation: -4768.9 m

Event(s):

MSM96_3-1 (KIEL0233GEAU201) * Latitude: 47.999980 * Longitude: -14.498330 * Date/Time: 2020-10-13T09:37:19 * Elevation: -4769.0 m * O2A Registry URI: https://registry.o2a-data.de/items/7428 * Location: North Atlantic Ocean * Campaign: (GPF 20‐3_088) * Basis: * Method/Device: (CTD-RO)

MSM96_19-1 (KIEL0233GENU201) * Latitude: 48.072750 * Longitude: -14.575270 * Date/Time: 2020-10-18T12:29:11 * Elevation: -4768.9 m * O2A Registry URI: https://registry.o2a-data.de/items/7428 * Location: North Atlantic Ocean * Campaign: (GPF 20‐3_088) * Basis: * Method/Device: (CTD-RO)

MSM96_32-1 (KIEL0233GEWU201) * Latitude: 38.096950 * Longitude: -17.486980 * Date/Time: 2020-10-26T15:44:14 * Elevation: -5264.9 m * O2A Registry URI: https://registry.o2a-data.de/items/7428 * Location: North Atlantic Ocean * Campaign: (GPF 20‐3_088) * Basis: * Method/Device: (CTD-RO)

Parameter(s):

#	Name	Short Name	Unit	Comment
1	Event label	Event
2	Date/Time of event	Date/Time
3	Latitude of event	Latitude
4	Longitude of event	Longitude
5	Station label	Station
6	Depth, bathymetric	Bathy depth	m
7	Sample code/label	Sample label
8	Filter	Filter
9	Yttrium	Y	µg/kg	ng/kg
10	Lanthanum	La	µg/kg	ng/kg
11	Cerium	Ce	µg/kg	ng/kg
12	Praseodymium	Pr	µg/kg	ng/kg
13	Neodymium	Nd	µg/kg	ng/kg
14	Samarium	Sm	µg/kg	ng/kg
15	Europium	Eu	µg/kg	ng/kg
16	Gadolinium	Gd	µg/kg	ng/kg
17	Terbium	Tb	µg/kg	ng/kg
18	Dysprosium	Dy	µg/kg	ng/kg
19	Holmium	Ho	µg/kg	ng/kg
20	Erbium	Er	µg/kg	ng/kg
21	Ytterbium	Yb	µg/kg	ng/kg
22	Lutetium	Lu	µg/kg	ng/kg
23	Manganese	Mn	µg/kg	ng/kg

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0) (License comes into effect after moratorium ends)

Status:

Curation Level: Enhanced curation (CurationLevelC)

Size:

76 data points

Download Data (login required)

Download dataset as tab-delimited text — use the following character encoding:

View dataset as HTML