Major element, trace element and Nd isotopes of cumulate plagioclase and clinopyroxene in lower crustal gabbros from Hess Deep oceanic crust, East Pacific Rise, with elemental maps of all studied samples

We collected major element, trace element and Nd isotopes of cumulate plagioclase and clinopyroxene in lower crustal gabbros from Hess Deep oceanic crust (~2°15'N, 101°30'W) to investigate the Nd isotopic heterogeneity of melts delivered to a complete section of Hess Deep oceanic crust, accreted at the fast-spreading (133 mm/yr) East Pacific Rise (EPR). These data are presented in Cooper et al. (2025) ( https://doi.org/10.1130/G52872.1). Elemental maps of 58 samples were initially obtained prior to selecting a subset of 25 samples for in-situ microanalysis. We targeted the Nd isotope record of cumulate plagioclase and clinopyroxene from lower crustal gabbro samples, representing early crystallisation products of melts delivered to the crust. These samples were collected in several expeditions: Ocean Drilling Program (ODP) Leg 147; RSS James Cook cruise JC21; Integrated Ocean Drilling Program (IODP) Expedition 345 (Site U). Combined, these studies provide the most complete composite section of fast-spreading EPR crust to date (stratigraphic depth of 4350 m to 25 m). In our study, we selected 25 samples for in situ Nd isotope microanalysis, covering the range of mineralogy and textural diversity, and over the full stratigraphic depth. For a comparison to local MORB compositions, we selected a set of 13 upper-crustal sheeted dikes collected on the RSS James Cook cruise JC21. Our data reveal that the mantle is heterogeneous at the scale of melt extraction, and the crystal record from the lower crust shows greater 143Nd/144Nd heterogeneity than the overlying MORB. Hence, Pacific MORBs do not reflect the full heterogeneity of their mantle source, and some aggregation of melts occurs within the crust. Data was collected between 2020 and 2023 by George Cooper, Johan Lissenberg and Max Jansen at Cardiff University, UK, as part of NERC Grant NE/T000317/1:HiDe: A Highly Heterogeneous Depleted Upper Mantle? Mineral isotopic analyses were performed on a Thermo Scientific TRITON Plus at the Vrije Universiteit in Amsterdam. The long-term average and reproducibility (2019–2022) for the JNdi-1 standard is 0.512094 ± 0.000011 2 SD (standard deviation; n = 28) with 1011Ω resistors (used for clinopyroxene) and 0.512105 ± 0.000044 2 SD (n = 45) with four 1013Ω resistors (used for plagioclase). Full methodology can be found within the supplemental Material of Cooper et al. (2025) at https://doi.org/10.1130/GEOL.S.28485770 The DOI is a supplement to https://doi.org/10.1130/G52872.1 Methodology: https://gsapubs.figshare.com/articles/journal_contribution/Supplemental_Material_Crustal_versus_mantle-level_aggregation_of_heterogeneous_melts_at_mid-ocean_ridges/28485770?file=52665137

Date (Creation): 2025-10-10

Citation identifier: http://data.bgs.ac.uk/id/dataHolding/13608544

Point of contact

Organisation name	Individual name	Electronic mail address	Role
University of Cardiff	Johan Lissenberg	not available	Originator
University of Cardiff	Marc-Alban Millet	not available	Originator
Cardiff University	George Cooper	not available	Originator
Vrije Universiteit	Janne M. Koorneef	not available	Originator
British Geological Survey	Enquiries	not available	Distributor
British Geological Survey	Enquiries	not available	Distributor
British Geological Survey	Enquiries	not available	Point of contact
British Geological Survey	Enquiries	not available	Point of contact

Maintenance and update frequency: notApplicable

GEMET - INSPIRE themes, version 1.0

Geology

BGS Thesaurus of Geosciences

MORB
NGDC Deposited Data
Major element analysis
Neodymium isotopes
Heterogeneity
Plagioclase
Citable Data
Gabbro
Oceanic crust
Clinopyroxene
Trace elements

dataCentre

Keywords

NERC_DDC

Access constraints: Other restrictions

Other constraints: licenceOGL

Other constraints: Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Use constraints: Other restrictions

Other constraints: The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.

Other constraints: Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Language: English

Topic category

Geoscientific information

Begin date: 2020-01-01

End date: 2023-01-01

Reference System Information

No information provided.

Distribution format

Name	Version
Microsoft Excel (XLSX)	witheld
Comma-separated values (CSV)	witheld

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	not available	Distributor

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	not available	Distributor

OnLine resource

Protocol	Linkage	Name
WWW:DOWNLOAD-1.0-http--download	https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item190265	Data

OnLine resource

Protocol	Linkage	Name
WWW:LINK-1.0-http--related	https://doi.org/10.5285/7cac54fd-7530-48f6-bb1e-3c103d9e4b23	Citation Information - Digital Object Identifier (DOI)

Hierarchy level: Non geographic dataset

Other: non geographic dataset

Conformance result

Title: INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology

Date (Publication): 2011

Explanation: See the referenced specification

Pass: No

Conformance result

Title: Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services

Date (Publication): 2010-12-08

Explanation: See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF

Pass: No

Statement: Elemental maps of all studied samples were carried out on a Zeiss Sigma HD field emission gun scanning electron microscope (SEM) at Cardiff University, UK. Mineral trace element concentrations were measured by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICPMS) (Applied Spectra Inc. RESOlution S-155 laser coupled to an Agilent 8900 ICP-QQQ). Nd concentrations were used to predetermine the sample volume needed to be recovered from micromilling. Typical Plagioclase and Clinopyroxene cores from each sample were drilled using a New Wave™ Research MicroMill. Milled powders were digested in HF and HNO3 prior to Nd separation by column chemistry. Mineral Isotopic analyses were performed on a Thermo Scientific TRITON Plus at the Vrije Universiteit, and whole-rock dike samples were measured on a Nu plasma II multicollector ICP-MS at Cardiff University.