Title: Magnesium isotope fractionation in biogenic and abiogenic carbonates: implications for paleoenvironmental proxies
Abstract: Abstract Geochemical variations in marine biogenic carbonates that are preserved in the geological record serve as proxies of past environmental change. However, interpreting most proxies is complicated by biologically-mediated vital effects, highlighting the need to develop new tools for reconstructing paleoenvironmental change. Recently, magnesium (Mg) isotope variability in carbonates has been explored extensively to determine its utility as a paleoenvironmental proxy. We review the results of these works, which have yielded valuable information on the factors affecting Mg isotope fractionation between carbonates and solution (Δ26Mgcarb-sol) in biogenic and abiogenic carbonate minerals. Strong evidence exists for a mineralogical control on Δ26Mgcarb-sol, with the negative offset from 0‰ following the sequence aragonite ∼3 mol/mol) and saturation states (Ω >∼3) that are similar to seawater suggest that Δ26Mgcarb-sol has a temperature dependence of ∼0.01‰ °C−1 and is insensitive to precipitation rate. In contrast, a significant precipitation rate dependence is observed in calcites precipitated from solutions with relatively low Mg/Ca ratios (
Publication Year: 2014
Publication Date: 2014-03-07
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 122
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