The University of Southampton
University of Southampton Institutional Repository

Integrated geochemical and morphological data provide insights into the genesis of ferromanganese nodules

Integrated geochemical and morphological data provide insights into the genesis of ferromanganese nodules
Integrated geochemical and morphological data provide insights into the genesis of ferromanganese nodules
Ferromanganese nodules grow by precipitation of metals from seawater and/or sediment pore water. The formation of different genetic types depends on the composition and redox conditions of the water and upper sediment layers, water depth, and primary productivity in surface waters. Many characteristics of nodules have been used to investigate their genesis. In this paper, we compare nodules from different environments using Computed Tomography, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, and Micro X-ray Fluorescence data to better understand how geochemical differences are linked to different morphological features. We use representative samples of purely hydrogenetic nodules and mixed-type nodules with various proportions of hydrogenetic and diagenetic growth laminae. Our results show a micrometric alternation between high-absorbance massive Mn-enriched (Mn/Fe up to 40) laminae and low-absorbance dendritic Mn-depleted (Mn/Fe about 1) laminae in mixed-type nodules, suggesting the rhythmic alternation of hydrogenetic oxic conditions and suboxic diagenetic input. This micro-rhythmic alternation is absent in purely hydrogenetic nodules, which are homogenous both chemically and morphologically. A conceptual model is proposed to account for these geochemical and morphological differences in terms of the vertical migration of the oxic-suboxic front relative to the base of the nodules.
0009-8558
Benites, Mariana
3cd05ec2-9d09-48a1-beeb-7aa94f203ae2
Millo, Christian
72d2248c-f7bf-4f44-b589-55c25a723518
Hein, James
47e6346b-deeb-4f9b-bd57-66fbaa964f82
Nath, Bejugam
a48bd3cb-bca8-4a57-ba10-02fa0aa4a08a
Murton, Bramley
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Galante, Douglas
414b3c4d-221e-479c-8d23-a45a7352952d
Jovane, Luigi
ab9a1a49-a542-42f8-8fac-db6f1e429d9c
Benites, Mariana
3cd05ec2-9d09-48a1-beeb-7aa94f203ae2
Millo, Christian
72d2248c-f7bf-4f44-b589-55c25a723518
Hein, James
47e6346b-deeb-4f9b-bd57-66fbaa964f82
Nath, Bejugam
a48bd3cb-bca8-4a57-ba10-02fa0aa4a08a
Murton, Bramley
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Galante, Douglas
414b3c4d-221e-479c-8d23-a45a7352952d
Jovane, Luigi
ab9a1a49-a542-42f8-8fac-db6f1e429d9c

Benites, Mariana, Millo, Christian, Hein, James, Nath, Bejugam, Murton, Bramley, Galante, Douglas and Jovane, Luigi (2018) Integrated geochemical and morphological data provide insights into the genesis of ferromanganese nodules. Clay Minerals, 8 (11), [488]. (doi:10.3390/min8110488).

Record type: Article

Abstract

Ferromanganese nodules grow by precipitation of metals from seawater and/or sediment pore water. The formation of different genetic types depends on the composition and redox conditions of the water and upper sediment layers, water depth, and primary productivity in surface waters. Many characteristics of nodules have been used to investigate their genesis. In this paper, we compare nodules from different environments using Computed Tomography, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, and Micro X-ray Fluorescence data to better understand how geochemical differences are linked to different morphological features. We use representative samples of purely hydrogenetic nodules and mixed-type nodules with various proportions of hydrogenetic and diagenetic growth laminae. Our results show a micrometric alternation between high-absorbance massive Mn-enriched (Mn/Fe up to 40) laminae and low-absorbance dendritic Mn-depleted (Mn/Fe about 1) laminae in mixed-type nodules, suggesting the rhythmic alternation of hydrogenetic oxic conditions and suboxic diagenetic input. This micro-rhythmic alternation is absent in purely hydrogenetic nodules, which are homogenous both chemically and morphologically. A conceptual model is proposed to account for these geochemical and morphological differences in terms of the vertical migration of the oxic-suboxic front relative to the base of the nodules.

Text
minerals-08-00488-v2 - Version of Record
Available under License Creative Commons Attribution.
Download (5MB)

More information

Accepted/In Press date: 19 October 2018
Published date: 26 October 2018

Identifiers

Local EPrints ID: 427562
URI: http://eprints.soton.ac.uk/id/eprint/427562
ISSN: 0009-8558
PURE UUID: b06aba1a-6db0-49fb-8d8f-68715ec53512

Catalogue record

Date deposited: 23 Jan 2019 17:30
Last modified: 16 Dec 2019 17:46

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×