Garnet could be the ultimate petrochronometer. Not only can you date it directly (with an
accuracy and precision that may surprise some), but it is also a common rock-forming and …

Chromium consists of four stable isotopes (50 Cr, 52 Cr, 53 Cr and 54 Cr) with natural
abundances of 4.35%, 83.79%, 9.50% and 2.36%, respectively (Rossman and Taylor 1998) …

The macronutrient phosphorus is thought to limit primary productivity in the oceans on
geological timescales. Although there has been a sustained effort to reconstruct the …

The history of atmospheric oxygen through the Mesoproterozoic Era is uncertain, but may
have played a role in the timing of major evolutionary developments among eukaryotes …

The enrichment and depletion of redox sensitive trace metals in marine sediments have
been used extensively as paleoredox proxies. The trace metals in shale are comprised of …

Terrestrial and lunar rocks share chemical and isotopic similarities in refractory elements,
suggestive of a common precursor. By contrast, the marked depletion of volatile elements in …

The geochemistry of global mantle melts suggests that both mid-ocean ridge basalts
(MORB) and ocean island basalts (OIB) sample lithological and temperature heterogeneities …

The oxygenation of the atmosphere—one of the most fundamental transformations in Earth's
history—dramatically altered the chemical composition of the oceans and provides a …

The stable chromium (Cr) isotope system has been used extensively over the past decade
as a paleoredox proxy. The prevailing view has been that Cr oxidation is essentially limited …

Chromium (Cr) is a redox-sensitive metal element with two natural oxidation states,
commonly as the soluble Cr (VI) oxyanion (CrO 4 2− or HCrO 4−) and the insoluble Cr (III) …