| Summary: | Marked by a progressive increase in the amplitude of climate oscillations and a shift towards a quasi-100 kyr frequency, the Early–Middle Pleistocene transition (EMPT), previously known as the Mid-Pleistocene Transition (or Mid-Pleistocene Revolution) (1.4–0.4 Ma), represents a fundamental shift in the Earth’s climate state. The physical and biotic responses to this transition, amplified by the growth of Northern Hemisphere ice sheets, have been profound. Two important paleomagnetic episodes characterize the EMPT, the Jaramillo Subchron (1.07–0.99 Ma) and the Matuyama–Brunhes Chron boundary (~773 ka). The latter has been chosen as the primary guide for the Lower–Middle Pleistocene Subseries boundary, as it lies at the approximate midpoint of the EMPT and aids in global recognition both in marine and terrestrial deposits. The Jaramillo Subchron has received less attention, but the late Early Pliocene is important in Europe because it saw the progressive transition from the Villafranchian to Galerian mammal faunas, and expansion of hominins into western and northern Europe. The Jaramillo Subchron is represented by Marine Isotope Stages (MIS) 31 to 28, with MIS 30 already showing the asymmetrical (saw-tooth) pattern characteristic of the Middle Pleistocene. Indeed, while variation in the 40-kyr band (obliquity) remains strong throughout the EMPT, low frequency variability begins at around 1250–1200 kyr, which coincides with a progressive increase in global ice volume. The early phase of the EMPT is characterized by important glaciations beginning with MIS 36 and continuing to MIS 22, a major intensification of the East Asian monsoon system, intensification of loess deposition in northern Europe, development of open landscapes in western Siberia, increased fluvial incision, higher amplitude sea-level change, and spread of large mammals across northern Eurasia, and a strong reduction in the North Atlantic thermohaline circulation. In Europe, the loss of thermophilous plant taxa during the EMPT and indeed throughout ...
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