Environment around 6 million BC

The Globe

...scientists know of only two layers of sediment “broadly distributed across several continents that exhibit coeval abundance peaks in a comprehensive assemblage of cosmic impact markers, including nanodiamonds, high-temperature quenched spherules, high-temperature melt-glass, carbon spherules, iridium and aciniform carbon.” These layers are found at the Cretaceous-Paleogene Boundary 65 million years ago, when it has long been agreed that a gigantic cosmic impact in the Gulf of Mexico caused the mass extinction of the dinosaurs, and at the Younger Dryas Boundary 12,800 years ago.  (America Before)


After a major cooling five to six million years ago, when changes in earth's orbit affected global climate, subtropical Africa's warm, moist environment was subject to oscillating cycles of cool, dry and warm, wet weather. Forested areas which proliferated in warm cycles, receded in cool cycles, allowing grasslands to take over until the climate shifted and woodlands returned. The cycles were relatively brief and mild, and had little effect on the evolution of animal species.(Patterns in Prehistory)

Southwest Asia




Indus Valley






South America




North America