Hey all,

The December issue of Geology had a little bit of everything for every shade of geobiologist. I linked the papers below.

...and the last one, for the more paleontologically inclined, suggests that tommotiids (enigmatic Early Cambrian fossils) maybe a stem group of phoronids and/or brachiopods based on similarities in their shell microstructure.

Happy New Year!

For the more microbially inclined, this paper suggests strategies that halophilic Archaea may utilize to survive for long periods of time in pockets of fluid trapped in evaporite minerals.

The second paper tries to link changes between the dominant marine carbonate mineralogies (i.e. aragonite and low-magnesium calcite) during the Phanerozoic to the inferred pCO2 of the atmosphere.

First one is by Justin Ries (now at UNC-Chapel Hill) concerning affects of acidification on a wide variety of calcifying organisms.

Hey everyone,

Here is a new Science paper from my old lab group. It discusses the first known appearance of euxinia in the geological record and its relation to the evolution of the oxygenation of the ocean/atmosphere.

Another paper of interest on biomarkers

Here is the other late Archean nitrogen isotope paper. Compare to Garvin et al in Science.

Hey all,
Here's another stromatolite paper. This one is by a friend in my former lab at Riverside. It tries to show that stromatolites from the Gunflint and Biwabik iron formations were iron-oxidizing bacteria and not cyanobacteria using iron isotopes and rare earth elements.

This article features new utility for rare sulfur and iron isotopes of pyrite: determining the source of detrital pyrites in two Archean successions. It also discusses the implications of the presence of detrital pyrite in samples on the secular trends in the rare sulfur isotope record of the Archean.

Along the lines of our discussion next Friday there is a new paper out in PPP discussing the Early Cambrian reefs in South China. Apparently the reefs on the Yangtze Platform were dominated by stromatolites and thrombolites.

Here is a paper exploring a new isotope system. Would be good to get the Hansel group's take on this, as their expertise is closely aligned with the microbial aspects of this geochemical cycle. Overall, as one might expect, there is a transition associated with the GOE.

Interesting article and perspectives piece on organisms that did *better* after the Permo-Triassic mass extinction, probably due to their physiology and pelagic habitat.