Microfossils from the Palaeoproterozoic Hutuo Group of Shanxi Province, China.
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Geological and geochemical evidence has revealed that the Neoarchean–Paleoproterozoic period was vitally important for Earth’s evolution. The earliest ‘snowball event’ and major glaciation occurred during this period. This was followed by a great oxidation event, which caused an abnormal positive shift in global carbon isotopes and is referred to as the Lomagundi Event. The emergence of oxygen-producing photosynthetic organisms that led to the sudden increase in atmospheric oxygen has been the focus of several studies. However, until now, convincing fossil records from this key geological time interval (i.e. latest Neoarchean to Palaeoproterozoic) are scarce. During this period, the biosphere experienced multiple geological events, but little is known about it and what is known is dependent on molecule clock dating analyses and estimates. To better understand the biosphere during this time, the metamorphosed Palaeoproterozoic deposits of the Hutuo Group at Wutai Mountain in Shanxi Province, China provide an excellent stratigraphic sequence in which to study well-preserved fossil records of this key period in Earth’s evolution.