During most of the last hundred years every car body, rebar rod in concrete, ship, bridge and skyscraper frame had its origins in vividly striped red rocks from vast open-pit mines. Comprising mainly iron oxides with some silica, these banded iron formations, or BIFs for short, occur in profitable tonnages on every continent.
2.1 billion years old boulder of banded ironstone. (credit: Wikipedia)
This article can now be read in full at Earth-logs in the Sedimentology and stratigraphy archive for 2017
Posted in Geobiology, palaeontology, and evolution, Planetary, extraterrestrial geology, and meteoritics, Sedimentology and stratigraphy
Tagged BIF, Early Earth system, Great Oxidation event, Ironstone formations, oxidation-reduction
The global glaciations of the Neoproterozoic that reached low latitudes – the so-called ‘Snowball Earth’ events have dominated accounts of ancient glaciations since the start of the 21st century. Yet they are not the oldest examples of large-scale effects of continental ice sheets. Distinctive tillites or diamictites that contain large clasts of diverse, exotic rocks occur in sedimentary sequences of Archaean and Palaeoproterozoic age.
Diamictite from the Palaeoproterozoic Gowganda Formation in Ontario Canada (credit: Canadian Sedimentology Research Group)
This item can be read in full at Earth-logs in the Palaeoclimatology archive for 2013