If subdivision is necessary, periods of human technological development, such as the Mesolithic, Neolithic, and Bronze Age, are usually used.
However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world.
In addition, many areas above about 40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as 180 m (590 ft) due to post-glacial rebound over the late Pleistocene and Holocene, and are still rising today.
According to some scholars, a third division, the Anthropocene, has now begun.
They find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest.
The scheme was defined for Northern Europe, but the climate changes were claimed to occur more widely.
Climate cyclicity through the Holocene (Bond events) has been observed in or near marine settings and is strongly controlled by glacial input to the North Atlantic.
At the same time spectral analyses of the continental record, which is remote from oceanic influence, reveal persistent periodicities of 1000 and 500 years that may correspond to solar activity variations during the Holocene epoch.
Holocene marine fossils are known, for example, from Vermont and Michigan.