0000000000063903
AUTHOR
Dieter Garbe-schönberg
Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean
12 pages, 5 figures, supporting information https://doi.org/10.1073/pnas.1918943117.-- Data Availability. Our published databases are publicly accessible for readers, and they are deposited at the NOAA NCEI at https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0171017.-- Correction for Lebrato et al., Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean; Proceedings of the National Academy of Sciences of the USA 118(49): e2119099118 (2021); doi: 10.1073/pnas.2119099118; http://hdl.handle.net/10261/258054.-- This is Pacific Marine Environmental Laboratory contribution number 5046
Geochemical implications for changing dust supply by the Indian Monsoon system to the Arabian Sea during the last glacial cycle
Element concentrations of 43 elements as well as inorganic and organic carbon content of sediment core 70KL from the western Arabian Sea were measured with high (1 cm) sample resolution. Principal components of the sediment’s chemical composition were determined with the help of statistical principle component analysis. These components are representing the major environmental factors at the site. The most important processes controlling the observed variations are the changing lithogenic influx derived from the major wind systems of the region (i.e., the Arabian northwesterly winds, the northeast winter monsoon and the southwest summer monsoon), summer monsoon associated upwelling and biog…
Experimental calibration and implications of olivine-melt vanadium oxybarometry for hydrous basaltic arc magmas
The strong dependence of vanadium partitioning between olivine and silicate melt (DVOl-M) on redox conditions (fO2) can be used as sensitive oxybarometer in magmatic systems. Here we extend the experimental database on DVOl-M, obtained so far at high temperatures (mainly above 1250 °C), to lower temperatures that are typical for island-arc basalts. Crystallization experiments were performed using a composition from Mutnovsky volcano (Kamchatka), and the investigated temperature, pressure, and oxygen fugacity ranges were 1025–1150 °C, 0.1 and 0.3 GPa, and ΔQFM of –0.5 to +3.2, respectively. The water content in melts ranged from 0.6 to ∼6.5 wt% H2O. The data demonstrate a strong negative cor…
Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica islandica</i>)&mdash;Comparison of ICP-OES and LA-ICP-MS data
The element chemistry of biogenic carbonates can provide important data on past environments. However, the Sr/Ca and Mg/Ca ratios as well as the Mg and Sr concentrations of biological carbonates, especially aragonitic bivalves often depart from apparent thermodynamic equilibrium. When measured in situ by means of LA-ICP-MS, the Mg concentration is often substantially enriched (two- to threefold) near the organic-rich, annual growth lines. To test the hypothesis that some organic components exert a major influence on the skeletal metal content, the element chemistry of different shell components (insoluble organic matrix, IOM; dissolved CaCO3 and soluble organics, SOM) of Arctica islandica w…
FeMnOx-1: A new microanalytical reference material for the investigation of Mn–Fe rich geological samples
Suitable Mn-Fe rich microanalytical reference materials (MRMs) as calibration material for laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) have not been available. The United States Geological Survey (USGS) in collaboration with the Max Planck Institute for Chemistry has prepared a synthetic MRM, FeMnOx-1, with elevated mass fractions of MnO (25 g/100 g), Fe2O3 (8.5 g/100 g) and high mass fractions of 25 trace elements varying between 200 and 5000 mg/kg. This new MRM has been designed as calibration material for a wide range of different Mn-Fe deposits, such as desert/rock varnish, ocean crusts and nodules as well as Mn accumulations in soils and lakes. Small-scale an…
Petrogenetic evolution of metabasalts and metakomatiites of the lower Onverwacht Group, Barberton Greenstone Belt (South Africa)
A well-preserved sequence, by Archean standards, of mantle-derived metabasalts and metakomatiites forms large parts of the lower Onverwacht Group of the Barberton Greenstone Belt (South Africa). To elucidate the origin of mafic and ultramafic rocks from this 3.55 to 3.45 Ga sequence, we present a comprehensive geochemical dataset including major and trace elements as well as Lu-Hf and Sm-Nd isotope compositions for a variety of metavolcanic rocks. These include metabasalts of the amphibolite-facies Sandspruit and Theespruit Formations as well as metabasalts and metakomatiites of the lower greenschist-facies Komati Formation. Based on their incompatible trace element patterns, the basalts of…