Publication: Molybdenum re-dissolves and re-precipitates in euxinic lake sediments

April 20, 2017By Tais W DahlPublication

In a paper published in Chemical Geology entitled: “Molybdenum isotope fractionation and speciation in a euxinic lake—Testing ways to discern isotope fractionation processes in a sulfidic setting”, we compare molybdenum isotope and speciation data from lake sediments deposited under euxinic (anoxic and sulfidic) waters. We conclude that the chemical Mo species present in sediments did not … Read More

Molybdenum review: The answer is 42

January 26, 2017By Tais W DahlPublication

Molybdenum is element number 42 in the periodic table. Although, this element is a trace constituent in the Earth and life, it currently deserves a lot of attention. With Brian Kendall and Ariel Anbar, I have written a review that brings the latest update on the various aspects of molybdenum isotopes and their current use in geochemistry, cosmochemistry and … Read More

Publication: Molybdenum interacts directly with organic matter in sulfidic environments

December 21, 2016By Tais W DahlPublication, Research

Molybdenum is one of the most powerful elements used to track hydrogen sulfide and oxygen in the ocean from the geological record. Still, we have an incomplete understanding of the chemical removal pathway between ocean and sediments.  Sediments deposited under anoxic and sulfidic waters display tight correlations between their contents of molybdenum (Mo) and total organic matter  (TOC). Yet, association does not mean causation. Instead, … Read More

Article in PNAS: Humble moss created modern O2 levels

August 15, 2016By Tais W DahlPublication

In a new modeling study led by Tim Lenton from University of Exeter, we found that the earliest land plants caused atmospheric O2 levels to increase above the “fire limit”, where stuff will ignite and burn. This result fits nicely with available geochemical and paleontological evidence, but previous theoretical models predicted either an earlier or a later rise of … Read More