New archaeological and geomorphologic data collected adjacent to the Aral Sea show lake-level stands during the late Pleistocene and the past 5000 years. On the northern and southern shores, archaeological sites from the Palaeolithic through the Late Middle Ages contain evidence of various cultures and economies. Changes in settlement activity during the mid-Holocene are related to several major lake-level oscillations. Some of them, especially those which occurred at approximately 350-450 cal B.P. (during the Little Ice Age), 700-780 cal B.P., around 1400 cal B.P., and 1600-2000 cal B.P., were accompanied by lithological changes in sediment cores retrieved from the Aral Sea and were observed in shoreline shifts. We show that a maximum lake level at 72-73 m above sea level cannot be corroborated. The highest lake level, which was reached at the beginning of the 20th century, probably never exceeded 54-55 m a.s.l. Furthermore, we documented a previously unknown low-level stand at 42-43 m a.s.l. that dated to the Bronze Age (~4000-3000 B.P.). The regression during 1200-1300 cal A.D. was formerly underestimated and was lower than the present-day lake level. The observed environmental changes, except those since the 1960s, are most probably driven by climate variability, though human activities (e.g., irrigation) can amplify the impact.

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Changing content of detrital input in laminated sediments traced by XRF scanning and microfacies analyses reflect prominent variations in sedimentation processes in the Aral Sea. A high-resolution record of titanium from a core retrieved in the northwestern Large Aral Sea allows a continuous reconstruction of wind strength and frequency in western Central Asia for the past 1500 yr. During AD 450–700, AD 1210–1265, AD 1350–1750 and AD 1800–1975, detrital inputs (bearing titanium) are high, documenting an enhanced early spring atmospheric circulation associated with an increase in intensity of the Siberian High pressure system over Central Asia. In contrast, lower titanium content during AD 1750–1800 and AD 1980–1985 reflects a diminished influence of the Siberian High during early spring with a reduced atmospheric circulation. A moderate circulation characterizes the time period AD 700–1150. Unprecedented weakened atmospheric circulation over western Central Asia are inferred during ca. AD 1180–1210 and AD 1265–1310 with a considerable decrease in dust storm frequency, sedimentation rates, lamination thickness and detrital inputs (screened at 40-μm resolution). Our results are concurrent with changes in the intensity of the Siberian High during the past 1400 yr as reported in the GISP2 Ice Core from Greenland.

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