The upper 7 m of the band of fossil soil
, or paleosol, contains more than 0.1 percent carbon, which is an unusually high concentration for Precambrian paleosol, Ohmoto says.
Their analysis of 1,300 fossil soil
samples from sites at or near where human ancestors and their relatives evolved shows that more than 70 percent of the sites had less than 40 percent woody cover, meaning they were wooded grasslands or grasslands.
They analyzed pollen from a marine core in the Bay of Bengal that included a layer of ash from the Toba eruption, and they looked at carbon isotope ratios in fossil soil
carbonates taken from directly above and below the Toba ash in three locations in central India.
They analysed tracers of ancient leaves and of burned organic matter left behind in paleosols (stratum or soil horizon), or fossil soils
, in northern Pakistan.
Adriana Timofiecsyk, agronomist and soil specialist for the Federation, said that the soils that are prevalent in the Cerrado region are what is known in geology as "fossil soils
," which are rich with iron and, surprisingly, adapt well to coffee and other agricultural crops.
Annie has also used fossil soils
to reconstruct the ancient environments and climates that existed during the time of the dinosaurs in Alberta.
Ancient fossil soils
could be found at just about anywhere in the part of the world, at practically every country under its river, volcano and other sediments.
"However, ancient fossil soils
-- the best indicators of ancient carbon dioxide levels in the atmosphere -- suggest only modest levels during the Archean.
Marty asserted that however, ancient fossil soils
- the best indicators of ancient carbon dioxide levels in the atmosphere - suggest only modest levels during the Archean.