Geochemistry of sediment cores from the Rainbow vent site, supplement to: Chavagnac, Valerie; German, Christopher R; Milton, J Andy; Palmer, Martin R (2005): Sources of REE in sediment cores from the Rainbow vent site (36°14'N, MAR). Chemical Geology, 216(3-4), 329-352


A geochemical investigation was carried out on two sediment cores collected at 2 and 5 km from the Rainbow hydrothermal vent site. Bulk sediment compositions indicate that these cores record clear enrichments in Fe, Cu, Mn, V, P and As from hydrothermal plume fallout (Cave et al., 2002, doi:10.1016/S0016-7037(02)00823-2). Sequential dissolution of the bulk sediments has been used to discriminate between a leach (biogenic and oxy-hydroxide) component and a residual phase (detrital and sulphide/sulphate fractions). Major element data (Al, Fe, Ti, Mn, Mg, Ca, Si and index%) reveal that the hydrothermal input, as recorded in the leach phase, is much stronger than apparent from bulk sediment analyses alone. REE patterns for the leach phase record contributions from both biogenic carbonate (mimicking seawater REE patterns) and hydrothermal oxy-hydroxides, with the latter exhibiting positive Eu anomalies (hydrothermal derived) and negative Ce anomalies (seawater derived). Based on major element and REE data, the residue contains contributions from aeolian dust input, local MORB material and a hydrothermal component. Ternary REE mixing calculations indicate that most of the REE within the residual fraction (~80%) is derived from hydrothermal material, while detrital contributions to the REE budget, as deep-sea clay and volcanic debris, are <20%. By combining bulk and REE data for the various end-member components of the residue, we calculate that the chemical composition of the residue hydrothermal end-member is high in Ca (6-15%) and with a Nd/Sr ratio of 0.004. These characteristics indicate the presence of low-solubility hydrothermal sulphate (rather than sulphide) material within the residue component of Rainbow hydrothermal sediments.

Related Identifier
Metadata Access
Creator Chavagnac, Valerie; German, Christopher R; Milton, J Andy; Palmer, Martin R
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2005
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 4 datasets
Discipline Earth System Research
Spatial Coverage (-33.905W, 36.247S, -33.882E, 36.259N); Atlantic
Temporal Coverage Begin 1998-06-27T12:29:00Z
Temporal Coverage End 1998-07-01T08:48:00Z