Microfossils, stromatolites, preserved lipids and biologically informative isotopic ratios
provide a substantial record of bacterial diversity and biogeochemical cycles in Proterozoic …

Carbonate minerals have precipitated from seawater for at least the last 3.8 billion years, but
changes in the physical and chemical properties of carbonate rocks demonstrate that the …

Abstract The Nonesuch Formation microbiota provide a window into ca. 1075 Ma life within
the interior of ancient North America. The Nonesuch water body formed following the …

Manganese oxides are often highly reactive and easily reduced, both abiotically, by a variety
of inorganic chemical species, and biologically during anaerobic respiration by microbes. To …

Abstract The Upper Carboniferous Ortokarnash manganese ore deposit in the West Kunlun
orogenic belt of the Xinjiang province in China is hosted in the Kalaatehe Formation. The …

Geological records of atmospheric oxygen suggest that pO 2 was less than 0.001% of
present atmospheric levels (PAL) during the Archean, increasing abruptly to a Proterozoic …

Much of what we know about the history of Earth's climate derives from the chemistry of
carbonate minerals in the sedimentary record. The oxygen isotopic compositions (δ 18 O) of …

Molar-tooth structure (MTS) is an unusual carbonate fabric that is composed of variously
shaped cracks and voids filled with calcite microspar. Despite a century of study, MTS …

Direct studies of recent epeiric seawater chemistry and their geological significance are
relatively few compared to the far more abundant studies from ancient epeiric marine …

The end-Permian mass extinction was the most severe biotic crisis in Earth's history. In its
direct aftermath microbial communities colonized some of the space left vacant after the …