Sulfur, with an atomic weight of 32.06, has four stable isotopes. By far the most abundant is
32 S, representing around 95% of the total sulfur on Earth. The next most abundant isotope …

Euxinic ocean conditions accompanied significant events in Earth history, including several
Phanerozoic biotic crises. By critically examining modern and ancient euxinic environments …

Fifty-eight rock chips from fifteen samples of sedimentary rocks from the Ramah Group (∼
1.9 Ga) in northeastern Labrador, Canada, were analyzed for major and minor elements …

Mass‐independent isotopic signatures for δ33S, δ34S, and δ36S produced in the photolysis
of sulfur dioxide exhibit a strong wavelength dependence. Photolysis experiments with three …

There are 2 principal avenues of inquiry relevant to reconstructing the history of the sulfur
cycle. One avenue relies on the comparison of molecular sequences derived from …

We comprehensively compile and review N content in geologic materials to calculate a new
N budget for Earth. Using analyses of rocks and minerals in conjunction with N–Ar …

There is a growing interest in the role of bedrock in global nitrogen cycling and potential for
increased ecosystem sensitivity to human impacts in terrains with elevated background …

Oceanic sulfate concentrations are widely thought to have reached millimolar levels during
the Proterozoic Eon, 2.5 to 0.54 billion years ago. Yet the magnitude of the increase in …

The stable isotope record of marine carbon indicates that the Proterozoic Eon began and
ended with extreme fluctuations in the carbon cycle. In both the Paleoproterozoic [2500 to …

Microorganisms have flourished in the oceans since at least 3.8 billion years (3.8 Gyr) ago,,
but it is not at present clear when they first colonized the land. Organic matter in some Au/U …