The composition, magnetic characteristics, and pollen content of sediments from two small kettle lakes near the prairie-forest border in west-central Minnesota were used to infer changes in terrestrial vegetation, shoreline erosion, eolian inputs, carbonate deposition, and aquatic productivity. Several important changes in sediment stratigraphy coincide closely with changes in the terrestrial pollen assemblage. Accumulation rates of organic, inorganic, and carbonate sediment fractions as well as the concentration of magnetic particulates increased abruptly as prairie replaced pine forest, and decreased gradually throughout the subsequent transitions to oak scrub, and later, mixed woodland. Results suggest that by its mediation of wind exposure, local vegetation may affect (1) influx of eolian particulates, (2) erosion of shorelines, (3) water circulation, and (4) carbonate equilibria. In addition, low rates of accumulation of organic matter and increased humidicity during periods of conifer vegetation suggest that humic matter leached from forest soils may influence lake-water chemistry and reduce productivity. Changes in lake level caused by differential rates of evapotranspiration of the various vegetation types (conifer forest, deciduous hardwood forest, brush scrub, and prairie) could not be detected. Sediment-forming processes can therefore be altered by changes in local terrestrial vegetation through several mechanisms that are independent of changes in lake level.

The Gesher Benot Ya'aqov archaeological site in the northern Dead Sea Rift of Israel contains Acheulian artifacts and middle Pleistocene fossils. Initial results of a new interdisciplinary study have shown that fluviolacustrine sediments of the Benot Ya'aqov Formation, which contains several archaeological occupations, were deposited in an embayment of the Hula Basin. They were subsequently deformed by tectonic activity associated with the Dead Sea Rift. Biostratigraphy, magnetostratigraphy, and K-Ar dating serve to constrain the age of the Benot Ya'aqov Formation to between 240,000 and 730,000 yr B.P. Archaeological excavation of three areas and two trenches at the new study area have produced abundant basalt, flint, and limestone artifacts, mammalian and avian fossils, and considerable plant material. The lithic materials provide an excellent opportunity to study large assemblages of in situ Acheulian artifacts, a rare phenomenon in the middle Pleistocene Levantine record. In addition, the organic materials will facilitate paleoenvironmental reconstructions from an ecological-floral perspective.

Insect fossils and pollen from late Pleistocene nonmarine peat layers were recovered from cores from the shelf region of the Chukchi Sea at depths of about 50 m below sea level. The peats date to 11,300−11,000 yr B.P. and provide a limiting age for the regional Pleistocene-Holocene marine transgression. The insect fossils are indicative of arctic coastal habitats like those of the Mackenzie Delta region (mean July temperatures = 10.6–14°C) suggesting that 11,000 yr ago the exposed Chukchi Sea shelf had a climate substantially warmer than modern coastal regions of the Alaskan north slope. The pollen spectra are consistent with the age assignment to the Birch Interval (14,000–9000 yr B.P.). The data suggest a meadow-like graminoid tundra with birch shrubs and some willow shrubs growing in sheltered areas.

Several samples of stalagmitic flowstone (Ensemble E) at Grotte du Lazaret (Nice, France) were dated by U-series isotopes. The results show that this speleothem began to grow about 130,000 yr B.P. and continued to about 70,000 yr B.P., coinciding almost exactly with the last interglaciation (isotope stage 5). Even though Ensemble E is not in direct stratigraphic relation with the cave deposits, this study shows that the Acheulian artifacts industry and fauna within Lazaret are older than the Riss/Wurm interglaciation.

Mollusk aminostratigraphy of Quaternary marine terrace sediments at Coquimbo Bay, Chile, combined with recently available electron spin resonance (ESR) ages, necessitates revision of the northern Chilean relative sea-level and terrace chronology. Protothaca and Mulinia d-alloisoleucine/l-isoleucine values define four aminozones which are consistent with available ESR ages. Terrace reoccupation during successive high sea-level stands is inferred on the basis of litho- and aminostratigraphically defined unconformities in terrace sediments. ESR data and a nonlinear kinetic racemization model give approximate numerical ages for the aminozones and thus yield estimates of net uplift rates. These rates, averaged over intervals of one to several hundred thousand years, have ranged from less than 0.1 m/1000 yr to no more than 0.2 m/1000 yr. Such slow uplift is the cause of terrace reoccupation, as the amount of uplift between successive glacioeustatic high sea-level stands is frequently not sufficient to isolate an earlier-formed abrasion platform from rising sea level during a subsequent high stand.

The Holocene pollen sequence in the Minnesota area is “asymmetric” around the so-called prairie period: the early Holocene is dominated by elm (with pine in the north) and the late Holocene by oak. The elm zone is interpreted as a manifestation of summer monsoonal rains enhanced by the Milankovitch insolation maximum, and the pine in the north is interpreted as a result of summer cooling near the retreating ice sheet. As the summer insolation waned during the Holocene, its associated monsoonal rains from the Caribbean moisture source lasted longer in the south (northeastern Iowa and southern Wisconsin), where the inferred mesic elm forest changed to prairie as late as 5000 yr B.P., compared to 8000 yr. B.P. in Minnesota (and 9000 yr B.P. in the Dakotas).

Details of short-term climatic variability are often lost from marine sediments through bioturbation in the upper, aerobic sediment layers. Alternatively, a high-resolution and dated record of climatic events may be obtained using material preserved in archaeological deposits. The Holocene history of the southern Benguela upwelling regime has been constructed from the oxygen isotope and mineral analysis of midden shells. Three discrete episodes of significant isotope enrichment corresponded to periods of glacial expansion in the northern hemisphere. Significant changes in shell mineralogy, which is a response to sea-surface temperatures, were also recorded. The timing and duration of these changes approximated those in the isotope record and may provide a link between events affecting the subcontinent and global temperature changes of the late Quaternary.

Precisely dated tree-ring sequences of larch (Larix cajanderi Mayr) extending from 1801–1980 ad from Kamchatka lying in the far east of Asian continent were studied to see the influence of volcanic eruptions on tree growth and to assess the potential of tree rings for dating ancient volcanic events. Nearby volcanic events are clearly reflected in ring-width patterns. Distinctly narrow rings are formed in the year following the year of eruption. Weaker eruptions, however, are marked by narrow rings in the year of eruption only. After strong eruptions, trees usually take 2 to 3 yr to return to normal growth. The results indicate that tree rings are useful for dating ancient volcanic events.