Featured Articles
Grove & Brown (2018) Magmatic processes leading to compositional diversity in igneous rocks: Bowen (1928) revisited

Grove and Brown present a perspective on the evolution of thought on the origin of compositional diversity in igneous rocks. They explore the difficulty Bowen faced due to a paucity of data and samples, noting that basalts from mid-ocean ridges had yet to be dredged from the ocean floor. During Bowen’s tenure, major element analyses could only be made on bulk rocks, with no trace element or… Read More

McCubbin et al., (2017) A Low O/Si Ratio on the Surface of Mercury: Evidence for Silicon Smelting?

The MESSENGER spacecraft, “collected data providing important insights into the structure, chemical makeup, and compositional diversity of Mercury.” The atypically low ratios of these Mercury measurements were contextualized and visualized by plotting previously known values of O wt% vs Si wt% from large compendia of Lunar and Martian data, meteoritic samples, and terrestrial rock data… Read More

Greber et al., (2017) Titanium isotopic evidence for felsic crust and plate tectonics 3.5 billion years ago

Using the titanium isotopic make up of shales, Greber et al. develop a proxy for reconstructing the SiO2 content of shale source rocks and thus the chemical composition of emerged crust. From this they construct a mixing model to translate titanium isotope values of shales into an estimate of the crustal composition, and an emergence of predominantly felsic crust since at least 3.5 Ga.  

Giovas thumbnail Giovas et al., (2016) Sr and Pb isotopic investigation of mammal introductions: Pre-Columbian zoogeographic records from the Lesser Antilles, West Indies

In a novel use of EarthChem data, Giovas et al., compile results from lithological studies of Pb isotope ratios to provide a framework for assessing bioavailable lead. The underlying lithology of a region contributes directly to bioavailable Sr and Pb. These isotopes are taken up during skeletal tissue formation with very little fractionation, thus the bioavialable fractions of Sr and Pb… Read More

Michael thumbnail Michael, P. and Graham, D. (2016) The behavior and concentration of CO2 in the suboceanic mantle: Inferences from undegassed ocean ridge and ocean island basalts

The amount of non-anthropogenic versus anthropogenic input of CO2 to the Earth’s atmosphere is currently a hotly debated topic. The most direct way to estimate volatile flux from the interior of the Earth is by measuring the concentration of the volatiles in basaltic magma as it moves to the surface. While the CO2 of naturally quenched glasses from mid-ocean ridge basalts (MORBs) and ocean… Read More