Next Article in Journal
The Mechanical and Microstructural Properties of Composite Structures Made of a Cement-Tailing Backfill and Rock Core
Next Article in Special Issue
Using Time-Series Videos to Quantify Methane Bubbles Flux from Natural Cold Seeps in the South China Sea
Previous Article in Journal
Density of NaAlSi2O6 Melt at High Pressure and Temperature Measured by In-Situ X-ray Microtomography
Previous Article in Special Issue
Compositional Variations and Genesis of Sandy-Gravel Ferromanganese Deposits from the Yōmei Guyot (Holes 431, 431A DSDP), Emperor Ridge
Open AccessArticle

XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer

1
Instituto Dom Luiz (IDL), Faculty of Sciences, University of Lisbon, Building C1, Campo Grande, 1749-016 Lisboa, Portugal
2
Institute of Science and Environment, University of Saint Joseph, Rua de Londres 116, Macau 999-078, China
3
CERENA-Natural Resources and Environment Studies Center, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
4
GEOMAR-Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany
*
Author to whom correspondence should be addressed.
Minerals 2020, 10(2), 160; https://doi.org/10.3390/min10020160
Received: 3 November 2019 / Revised: 26 January 2020 / Accepted: 8 February 2020 / Published: 12 February 2020
(This article belongs to the Special Issue Marine Geology and Minerals)
The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat > 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time. View Full-Text
Keywords: seafloor mining; Mid Atlantic Ridge; TAG hydrothermal field; sediment cores; XRD; sequential extraction with acetate buffer; lightness parameter (L*) seafloor mining; Mid Atlantic Ridge; TAG hydrothermal field; sediment cores; XRD; sequential extraction with acetate buffer; lightness parameter (L*)
Show Figures

Graphical abstract

MDPI and ACS Style

Milinovic, J.; Dias, Á.A.; Janeiro, A.I.; Pereira, M.F.C.; Martins, S.; Petersen, S.; Barriga, F.J.A.S. XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer. Minerals 2020, 10, 160. https://doi.org/10.3390/min10020160

AMA Style

Milinovic J, Dias ÁA, Janeiro AI, Pereira MFC, Martins S, Petersen S, Barriga FJAS. XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer. Minerals. 2020; 10(2):160. https://doi.org/10.3390/min10020160

Chicago/Turabian Style

Milinovic, Jelena; Dias, Ágata A.; Janeiro, Ana I.; Pereira, Manuel F.C.; Martins, Sofia; Petersen, Sven; Barriga, Fernando J.A.S. 2020. "XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer" Minerals 10, no. 2: 160. https://doi.org/10.3390/min10020160

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop