The discovery by Farquhar et al. (1) of mass-independent isotope fractionation of S and S in rocks formed more than ;2 billion years ago (Ga), but not in younger rocks, has boosted the theory postulating a dramatic change from an anoxic to an oxygen-rich atmosphere about 2 Ga. That is because the only known natural process that may cause mass-independent fractionation of both S and S involves a...

The eumetazoan clade of modern animals includes cnidarians, acoels, deuterostomes, and protostomes. Stem group eumetazoans evolved in the late Neoproterozoic, possibly before the Marinoan glaciation, according to a variety of different kinds of evidence. Here, we combine this evidence, including paleontological observations, results from molecular and morphological phylogeny, and paleoecologica...

Three lines of evidence for ancient life on land are paleosols, microfossils, and MISS (microbially induced sedimentary structures). The three appear in the rock record as old as 3.5–2.7 Ga (Hallbauer and van Warmelo 1974; Rye and Holland 2000; Wacey et al. 2008; Johnson et al. 2010; Noffke et al. 2013). The primitive terrestrial biosphere is plausibly as old as the oldest marine biosphere (Sch...

The antiquity and global abundance of the enzyme, RuBisCO, attests to the crucial and longstanding role it has played in the biogeochemical cycles of Earth over billions of years. The counterproductive oxygenase activity of RuBisCO has persisted over billions of years of evolution, despite its competition with the carboxylase activity necessary for carbon fixation, yet hypotheses regarding the ...

Climate is an important environmental parameter of the early Earth, likely to have affected the origin and evolution of life, the composition and mineralogy of sedimentary rocks, and stable isotope ratios in sedimentary minerals. There is little observational evidence constraining Precambrian climates. Most of our knowledge is at present theoretical. Factors that must have affected the clima...

In North Gujarat, local communities depend on the Precambrian basement aquifers for their primary source of water supply. The increasing demand potable puts stress exploring ground...

Late Neoproterozoic-Early Cambrian schists have been occurred in southwest of Zanjan city from the Soltanieh belt. The Soltanieh belt in northwest of Iran is uplifted basement of Precambrian-Paleozoic in main central Iran zone and includes outcrops of Precambrian, Paleozoic and Mesozoic Formations. Late Neoproterozoic-Early Cambrian schists, the oldest stratigraphy unit in the region, consist o...

The Gamburtsev Subglacial Mountains (GSMs) in the interior East Antarctic Craton are entirely buried under massive ice sheet, with a ~50–60 km thick crust and ~200 lithosphere, but little is known of crustal structure uplift mechanism. Here, we use airborne gravity aeromagnetic anomalies for characteristic analysis inverse calculations. magnetic images show three distinct geophysical domains. B...