<Tr> <Td> n / a </Td> <Td> Phanerozoic </Td> <Td> Cenozoic </Td> <Td> Quaternary </Td> <Td> Holocene </Td> <Td> <P> chrons: Subatlantic Subboreal Atlantic Boreal Preboreal </P> </Td> <Td> Quaternary Ice Age recedes, and the current interglacial begins; rise of human civilization . Sahara forms from savannah, and agriculture begins . Stone Age cultures give way to Bronze Age (3300 BC) and Iron Age (1200 BC), giving rise to many pre-historic cultures throughout the world . Little Ice Age (stadial) causes brief cooling in Northern Hemisphere from 1400 to 1850 . Following the Industrial Revolution, atmospheric CO levels rise from around 280 parts per million volume (ppmv) to the current level of 400 ppmv . </Td> <Td> 0.0117 </Td> </Tr> <P> chrons: Subatlantic Subboreal Atlantic Boreal Preboreal </P> <Tr> <Td> Pleistocene </Td> <Td> Late (locally Tarantian Tyrrhenian Eemian Sangamonian) </Td> <Td> Flourishing and then extinction of many large mammals (Pleistocene megafauna). Evolution of anatomically modern humans . Quaternary Ice Age continues with glaciations and interstadials (and the accompanying fluctuations from 100 to 300 ppmv in atmospheric CO levels), further intensification of Icehouse Earth conditions, roughly 1.6 Ma . Last glacial maximum (30000 years ago), last glacial period (18000--15000 years ago). Dawn of human stone - age cultures, with increasing technical complexity relative to previous ice age cultures, such as engravings and clay statues (e.g. Venus of Lespugue), particularly in the Mediterranean and Europe . Lake Toba supervolcano erupts 75000 years before present, causing a volcanic winter that possibly pushes humanity to the brink of extinction . Pleistocene ends with Oldest Dryas, Older Dryas / Allerød and Younger Dryas climate events, with Younger Dryas forming the boundary with the Holocene . </Td> <Td> 0.126 </Td> </Tr> <Tr> <Td> Middle (formerly Ionian) </Td> <Td> 0.781 </Td> </Tr>

How the earth's history can be interpreted from the geologic time scale