Eocene

The Eocene epoch (56-34 mya) is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. The Eocene spans the time from the end of the Paleocene epoch to the beginning of the Oligocene epoch. The start of the Eocene is marked by the emergence of the first modern mammals. The end is set at a major extinction event that may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. Still, as with other other geologic periods, the strata that define the start and end of the epoch are well identified, but their exact dates are slightly uncertain.

Eocene flora

At the beginning of the Eocene, the high temperatures and warm oceans created a moist, balmy environment, with spreading throughout the earth from pole to pole.

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Cooling began mid-period, and by the end of the Eocene continental interiors had begun to dry out, with forests thinning out considerably in some areas. The newly-evolved grasses were still confined to river banks and lake edges, and had not yet expanded into plains and savannas.

Related Topics:
Grasses - Plains - Savanna

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The cooling also brought seasonal changes. Deciduous trees, better able to cope with large temperature changes, began to overtake evergreen tropical species. By the end of the period, deciduous forests covered large parts of the northern continents, including North America, Eurasia and the Arctic, and rainforests held on only in equatorial South America, Africa, India and Australia.

Related Topics:
Deciduous - Evergreen - Arctic - South America - Australia

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Antarctica, which began the Eocene fringed with a sub-tropical rainforest, became much colder as the period progressed; the heat-loving tropical flora was wiped out, and by the beginning of the Oligocene the continent hosted deciduous forests and vast stretches of tundra.

Related Topics:
Oligocene - Tundra

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