Earth’s Volatile Beginnings

Abstract

In this chapterwe discuss Earth’s early prebiotic history and the conditions underwhich life emerged. The chapter focuses in particular on the sources and fate of the volatiles that degassed from the Earth’s interior and formed its atmosphere, hydrosphere, and sedimentary rocks, giving rise to the global carbon cycle. The chapter also discusses the cooling history and compositional changes of the primordial atmosphere and the early oceans up to the time when life appears. The environmental conditions and the material and energy sources of the early organismal groups are primarily inferred from those of the chemosynthesizing and photosynthesizing organisms of the present.