Water in Early Earth

Early Earth

Photosynthesis and early Earth

Life has been built on the evolution and innovation of microbial metabolisms. Even with our scant understanding of the full diversity of microbial life, it is clear that microbes have become integral components of the biogeochemical cycles that drive our planet. The antiquity of life further suggests that various microbial metabolisms have been core and essential to global elemental cycling for...

A cool early Earth?

No known rocks have survived from the first 500 m.y. of Earth history, but studies of single zircons suggest that some continental crust formed as early as 4.4 Ga, 160 m.y. after accretion of the Earth, and that surface temperatures were low enough for liquid water. Surface temperatures are inferred from high d18O values of zircons. The range of d18O values is constant throughout the Archean (4...

Rethinking early Earth phosphorus geochemistry.

Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compou...

Petrological Evidence from Komatiites for an Early Earth Carbon and Water Cycle

Komatiites from Alexo and Pyke Hill in the Archean Abitibi greenstone belt provide petrological evidence for an early Earth carbon and water cycle, ingassing in the cool Hadean and outgassing in the hot Archean. The komatiites have SiO2 contents that are lower than those expected of advanced volatile-free melting of mantle peridotite. The SiO2 misfit cannot be plausibly accounted for by variati...