58e96d07-0129-b2c6-e063-3050940a6bde English dataset British Geological Survey +44 115 936 3100 United Kingdom enquiries@bgs.ac.uk pointOfContact 2026-08-25 UK GEMINI 2.3 http://data.bgs.ac.uk/id/dataHolding/13608758 WGS 84 (EPSG::4326) Geochemical and mineralogical analyses of deep-sea bulk sediment and porewaters from the Ocean Minerals Company (OMCO) 1979 test mining site in the Clarion-Clipperton Zone of the Central Pacific Ocean (Expedition JC241 in 2023) 2026-08-12 creation http://data.bgs.ac.uk/id/dataHolding/13608758 This dataset contains the results of pore water chemistry, sediment composition, and dissolved oxygen content and includes X-ray diffraction (XRD) analysis of mineralogy, particle-size distribution, and clay surface area. The results, provided in a Microsoft Excel spreadsheet, were analysed from seafloor sediment samples collected as part of the Seabed Mining And Resilience To EXperimental impact (SMARTEX) Highlight Topic project funded by the UK Natural Environment Research Council (Whole Grant Reference NE/T003537/1) alongside other partner institutions in the project. Porewaters were extracted to analyse for trace metals (by ICP-MS), nutrients and alkalinity. Sediments were analysed for trace element geochemistry, loss on drying, particle size analysis and bulk and clay mineralogy by XRD. Dissolved oxygen measurements taken offshore immediately following core collection are also included. Separate datasets associated with the same project cover the geochemistry of nodules and physical property analysis of sediment collected to model the physical and temporal responses of deep-sea sediment to the compression caused by a deep-sea mining vessel. The samples were collected as part of Expedition JC241 2023 in the Ocean Minerals Company (OMCO) test mining site in the Clarion-Clipperton Zone of the Central Pacific Ocean. More information, location and the cruise report are available at www.bodc.ac.uk/resources/inventories/cruise_inventory/report/18136/ Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk originator Enquiries British Geological Survey United Kingdom not available distributor Enquiries British Geological Survey not available originator Enquiries British Geological Survey United Kingdom not available pointOfContact notApplicable https://resources.bgs.ac.uk/images/geonetworkThumbs/58e96d07-0129-b2c6-e063-3050940a6bde.png Geology GEMET - INSPIRE themes, version 1.0 2008-06-01 publication Marine mining Biogeochemistry X ray diffraction Geochemistry Deep sea sediments Pore water BGS Thesaurus of Geosciences 2022 revision Citable Data NGDC Deposited Data dataCentre NERC_DDC otherRestrictions restricted The dataset has been formally approved by BGS for access by external clients under a BGS Digital Data Licence, issued via BGS's IPR Section. The dataset must not be provided to, or be accessible by, an external client until the IPR Section confirms that signed licence documentation is in place. Refer to the IPR Section (DigitalLE@bgs.ac.) if further advice is required.. Constraint applies until 2028-05-30 otherRestrictions 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. Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]" vector English geoscientificInformation British Geological Survey Gazetteer: Gazetteer of sea areas 2010 revision PACIFIC OCEAN [id=2002258] -126.1400 -126.1200 13.4300 13.4500 2021-06-01 2026-05-30 Microsoft Excel Spreadsheet (.xlsx) Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey United Kingdom not available distributor https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item193118 WWW:DOWNLOAD-1.0-http--download Data download https://doi.org/10.5285/4cfbc80b-7b70-4af3-a284-e86de6e3d592 WWW:LINK-1.0-http--related Citation Information - Digital Object Identifier (DOI) Grant, H., Josso, P., Chenery, S., Kemp, S., Kalra, M. (2026). Geochemical and mineralogical analyses of deep-sea bulk sediment and porewaters from the Ocean Minerals Company (OMCO) 1979 test mining site in the Clarion-Clipperton Zone of the Central Pacific Ocean (Expedition JC241 in 2023). NERC EDS National Geoscience Data Centre. (Dataset). https://doi.org/10.5285/4cfbc80b-7b70-4af3-a284-e86de6e3d592 information dataset dataset INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology 2011 publication See the referenced specification false 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 2010-12-08 publication See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF false Sediment samples were collected from megacores (max 60 cm), pushcores (max 30 cm, one pushcore of 60 cm) and gravity cores. Megacores and gravity cores were wireline deployed over the vessel side. ROV video footage and imaging allowed groundtruthing and precise landing location for megacores and gravity cores. Push cores were taken by ROV. Gravity cores were sectioned into 1 m sections labelled (surface) A to E (base). Sediment samples were collected using cut off syringes and porewater extracted using rhizomes and split into aliquots for different analyses. Megacore and pushcore sediment was sampled by extrusion and slicing 1 cm slices in the top 10 cm, 2 cm slices below 10 cm. Porewater was extracted at similar intervals using rhizomes. Dissolved oxygen measurements were taken using oxygen probes following collection at comparable intervals to sediment and porewater sampling.