Reanalysis and additional dating of the Devils Hole δ18O paleotemperature record confirm that the last interglaciation in the Great Basin (the continental analog of marine isotopic substage 5e) lasted ∼22,000 yr, consistent with the Vostok paleotemperature record which suggests a duration of ∼19,000 yr for this event in Antarctica. The three preceding interglaciations in the Devils Hole record (analogs of marine isotopic substages 7e, 9c, and 11c) range from 20,000 to 26,000 yr in duration. A ∼20,000-yr duration for the last interglaciation is consistent with TIMS uranium-series dated sea-level high stands. Thus, the widely held view that interglaciations were of 11,000- to 13,000-yr duration and constituted only about 10% of mid-to-late Pleistocene climatic cycles needs reexamination. The warmest portion of each interglaciation in the Devils Hole time series is marked by a δ18O plateau, signifying apparent climatic stability for periods of 10,000- to 15,000-yr duration.

A 25-m-thick section of mostly eolian sediment is exposed in the stream-cut flank of a sand ramp accumulated in a mountain saddle near Ardakan playa, central Iran. The well-sorted eolian sediments of the ramp contain talus beds and incipient paleosols. Morphology and bedding structures imply that southeasterly winds were primarily responsible for deposition of the eolian sand. Optical dating shows that the sand was deposited near the last glacial maximum within about 5000 yr. Surface stabilization, lack of surface scree, and the development of a stream cut between the mountain and the ramp show that sediment accumulation ceased after this time. The Siberian high pressure system may have been established over central Iran during the last glacial maximum, causing cooler temperatures and a prevalence of southeasterly winds. These colder, windier conditions would have led to frost shattering and eolian transport, both of which are not significant processes today but which are evident as past processes from the ramp sediments.

The age of sand dunes in the Nebraska Sand Hills has been controversial, with some investigators suggesting a full-glacial age and others suggesting that they were last active in the late Holocene. New accelerator mass spectrometry radiocarbon ages of unaltered bison bones and organic-rich sediments suggest that eolian sand deposition occurred at least twice in the past 3000 14C yr B.P. in three widely separated localities and as many as three times in the past 800 14C yr at three other localities. These late Holocene episodes of eolian activity are probably the result of droughts more intense than the 1930s “Dust Bowl” period, based on independent Great Plains climate records from lake sediments and tree rings. However, new geochemical data indicate that the Nebraska Sand Hills are mineralogically mature. Eolian sands in Nebraska have lower K-feldspar (and K2O, Rb, and Ba) contents than most possible source sediments and lower K-feldspar contents than dunes of similar age in Colorado. The most likely explanation for mineralogical maturity is reduction of sand-sized K-feldspar to silt-sized particles via ballistic impacts due to strong winds over many cycles of eolian activity. Therefore, dunes of the Nebraska Sand Hills must have had a long history, probably extending over more than one glacial–interglacial cycle, and the potential for reactivation is high, with or without a future greenhouse warming.

Geomorphic features and Pleistocene deposits on Huangshan have been attributed to glaciation. Recent reassessment questions this interpretation. As part of the reassessment, quartz sand grains from deposits identified as glacial boulder clays (till composed of boulders in a clay or silt matrix) were analyzed by scanning electron microscope for evidence of their sedimentary history. Surface textures found on the boulder-clay grains were compared with those on grains with known sedimentary histories including glacial, grus, colluvial, and alluvial grains. The analysis shows that the grains lack typical glacial textures. The surface textures present indicate a complex history. Nonuniformly weathered grain surfaces point to chemical weathering of the source rock. This is supported by the deep weathering of the nonquartz clasts in the sand-sized fraction as well as in boulders at the outcrops. The close correspondence in surface-texture frequencies with those of the alluvial grains indicates an alluvial component to the grains’ history. The similarity with the colluvial grains and the outcrops’ structures suggest an alluvial/colluvial origin for the deposits. The history indicated by the surface textures agrees with the recent reassessment of the geomorphic features and points to warm climatic conditions in east-central China for at least part of the Pleistocene.

Ring-width chronologies of Himalayan cedar (Cedrus deodara (D. Don.) G. Don.), Himalayan pine (Pinus wallichiana A. B. Jackson), and Himalayan spruce (Picea smithiana (Wall.) Boiss.) from the western Himalayan region, India, have been used to reconstruct mean April–May temperature back to A. D. 1698. The reconstruction correlates significantly with the average April–May instrumental temperature record (r= +0.62, 1876–1988) and is characterized by annual to multiyear fluctuations. The most striking feature of the present reconstruction is the absence of any warming trend in the 20th century. Relationships between the mean April–May temperature for the western Himalayan region, Indian summer monsoon rainfall, and Southern Oscillation Index indicate that the tree-ring chronologies, as surrogate temperature records, will provide valuable data for climate change studies with regional and global perspectives.

Two sand sheets underlying tidal marshes at Fair Harbour, Neroutsos Inlet, and Koprino Harbour on the northwestern coast of Vancouver Island, British Columbia, were probably deposited by tsunamis. The sand sheets become thinner and finer-grained landward, drape former land surfaces, contain marine microfossils, are locally graded or internally stratified, and can be correlated with earthquakes that generated tsunamis in the region. 137Cs dating and historical accounts indicate that the upper sand sheet was deposited by the tsunami from the great Alaska earthquake in 1964. Radiocarbon ages on plant fossils within and on top of the lower sand sheet show that it was deposited sometime after about A.D. 1660. We attribute the lower sand sheet to a tsunami from the most recent plate-boundary earthquake on the Cascadia subduction zone about 300 yr ago, extending the documented effects of this earthquake north of the Nootka fault zone. The 1964 tsunami deposits differ little in thickness and continuity among the three marshes. In contrast, the lower sand sheet becomes thinner and less continuous to the north, implying a tsunami source south of the study area.

A 4.5-m-thick late-glacial pollen sequence, supported by 17 AMS 14C dates, has been investigated at the Quintanar de la Sierra marshland (Iberian cordillera, north-central Spain). Pollen zones were defined that correspond to successive phases in vegetation history during the end of the Late Würm, late-glacial interstade, and Younger Dryas periods. A transfer function approach has been adopted to derive quantitative climate estimates from the pollen assemblage data. A first expansion ofJuniperus and Hippophae, about 13,500 14C yr B.P., indicates the beginning of the late-glacial interstade which is characterized by a Juniperus–Betula–Pinus succession that suggests higher temperatures and moisture than during full-glacial time. The Younger Dryas interval is recorded by a 120-cm-thick sediment unit that is dominated by herbaceous pollen. Transfer function estimates suggest that the climate during this period was cold, with low precipitation during most of the year, although not in summer. The Holocene arboreal recolonization in the area started about 10,000 14C yr B.P., with a renewed Juniperus–Betula–Pinus succession related to a strong increase in annual temperature and precipitation. The start of this process was synchronous with mean sea-surface temperature changes, as recorded from the nearby SU 81-18 marine core. The strong affinity with other European late-glacial pollen sequences demonstrates that the pattern of climatic changes during the last glacial–interglacial transition was similar in both northwestern and southwestern Europe.

Nerja Cave is a karstic cavity used by humans from Late Paleolithic to post-Chalcolithic times. Remains of molluscan foods in the uppermost Pleistocene and Holocene sediments were studied with cluster analysis and principal components analysis, in bothQ and R modes. The results from cluster analysis distinguished interval groups mainly in accordance with chronology and distinguished assemblages of species mainly according to habitat. Significant changes in the shellfish diet through time were revealed. In the Late Magdalenian, most molluscs consumed consisted of pulmonate gastropods and species from sandy sea bottoms. The Epipaleolithic diet was more varied and included species from rocky shorelines. From the Neolithic onward most molluscs consumed were from rocky shorelines. From the principal components analysis inQ mode, the first factor reflected mainly changes in the predominant capture environment, probably because of major paleogeographic changes. The second factor may reflect selective capture along rocky coastlines during certain times. The third factor correlated well with the sea-surface temperature curve in the western Mediterranean (Alboran Sea) during the late Quaternary.

Hominids left Africa and occupied mainland Asia by 1.8 myr ago. About 1.15 myr ago Homo erectus and an associatedStegodon–Ailuropoda fauna migrated from subtropical China across the Qinling Mountains into the temperate Loess Plateau. This migration may be an evolutionary milestone in human adaptability because it may represent the first occupation of a nontropical environment. Loess–paleosol stable isotope ratios from the last interglacial–glacial cycle provide comparative data for reconstructing the hominid paleoenvironments. The climate during Gongwangling hominid occupation about 1.15 myr ago was influenced by both Siberian–Mongolian winter and Indian summer monsoon systems characterized as a cold/cool, dry winter and warm/mild, semihumid summer and fall. The Gongwangling hominids preyed mainly on warm-climate-adapted animals such asStegodon–Ailuropoda fauna, suggesting a warm season occupation. The stable isotope ratios also indicate that the Chenjiawo hominids occupied an environment similar to that of the Gongwangling about 650,000 yr ago. The associated fauna, with a mixture of forest and steppe, warm- and cold/cool-climate-adapted animal assemblage's, suggests a permanent occupation by this time. Thus, the reliable earliest and permanent occupation of temperate environments may have occurred 150,000 yr earlier in eastern Asia rather than in Europe.

Twenty archaeological campsites intercalated between more than 30 debris flows caused by heavy rainfall events between 6200 and 3100 14C yr B.P. have recently been discovered at Quebrada Puripica in the Atacama Desert of northern Chile. This record provides detailed information about extreme, short-lived climatic events during the hyperarid mid-Holocene period. For the first time, we found evidence of continuous human occupation in this area, filling the regional hiatus in the Atacama basin (“Silencio Arqueologico”) between 8000 and 4800 14C yr B.P. The transformation of Early Archaic hunters into the complex Late Archaic cultural tradition was an adaptive process. During this time, the site was a local ecological refuge with abundant resources in a generally hostile environment.