Earth's Earliest Travertines.

摘要: In contrast to a rather extensive marine sedimentary record of the Palaeoproterozoic, terrestrial record, preserved as palaeosols (ancient soils; Retallack 2001) and caliches or calcretes (carbonate layers in palaeosols; Wright Tucker 1991), is sparse. Nevertheless, these deposits are important, because they have potential provide least ambiguous information on climatic atmospheric compositional change during this critical interval Earth history. best circumstances, sediments oceanic conditions, which can differ markedly from especially terms redox. modern world, soil environments themselves poorly reflect those at surface, CO2 O2 partial pressure, respiration by roots microbes. But with its presumably developed biota, conditions likely track atmosphere much more closely. (We use “presumably” here, ecosystems may been (Horodyski Knauth 1994; Watanabe et al. 2000), land surface incubator for early evolutionary innovation, including origin cyanobacteria; e.g. Battistuzzi 2009).