Using the concept of “orbital tuning”, a continuous, high-resolution deep-sea chronostratigraphy has been developed spanning the last 300,000 yr. The chronology is developed using a stacked oxygen-isotope stratigraphy and four different orbital tuning approaches, each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data. Each approach yields a separate chronology. The error measured by the standard deviation about the average of these four results (which represents the “best” chronology) has an average magnitude of only 2500 yr. This small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used. Excellent convergence between chronologies developed using each of five different paleoclimatological indicators (from a single core) is also obtained. The resultant chronology is also insensitive to the specific indicator used. The error associated with each tuning approach is estimated independently and propagated through to the average result. The resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr, in excellent agreement with the 2500-yr estimate. Transfer of the final chronology to the stacked record leads to an estimated error of ±1500 yr. Thus the final chronology has an average error of ±5000 yr.

A 500-m section of the Palm Spring Formation in the southern Mecca Hills, located within the San Andreas fault zone in southeastern California, has been paleomagnetically sampled to determine possible tectonic rotation in this area and to establish time-stratigraphic control. This work was partly stimulated by the fact that 80 km farther south, previous studies demonstrated 35° of postdepositional rotation in the Palm Spring Formation of the Vallecito-Fish Creek basin east of the Elsinore fault. Several lines of evidence suggest that hematite is the main magnetic carrier of the Mecca Hills samples. Large anhedral hematite grains observed in magnetic extracts and a positive fold test imply a detrital origin of the remanence. The polarity reversal patterns, together with earlier vertebrate paleontologic studies, restrict the time span for deposition of this unit to the middle-late Matuyama chron (2.0–0.75 myr ago), thus of uppermost Pliocene and early Pleistocene age. Characteristic directions of best least-squares fit for 73 samples suggest little or no overall rotation, despite the severe late Quaternary tectonic activity demonstrated by the intense deformation of these strata.

Radiocarbon-dated whalebones from raised beaches record a relative sea-level history for Bröggerhalvöya, western Spitsbergen that suggest a two-step deglaciation on Svalbard at the end of the late Weichselian glaciation. The late Weichselian marine limit was reached at about 13,000 yr B.P. and was followed by relatively slow emergence until about 10,000 yr B.P. either in response to ice unloading in the Barents Sea, initial retreat of local fjord glaciers, or some combination of the two. Rare whale skeletons dating between 13,000 and 10,000 yr B.P. indicate that the Norwegian Sea was at least seasonally ice free during that interval. Deglaciation of Spitsbergen is recorded by the rapid emergence of Bröggerhalvöya after 10,000 yr B.P. This was followed by a transgression during the mid-Holocene, here named the Talavera Transgression, and another in modern times. Raised beach morphologies suggest striking differences in nearshore depositional processes before and after 10,000 yr B.P. that are probably related to changes in the rate of uplift and in sea-ice conditions.

Plant macrofossils from 21 pack rat (Neotoma sp.) middens at 535–605 m from the Puerto Blanco Mountains, southwestern Arizona, provide and excellent history of vegetation and climate for the last 14, 120 yr B.P. in the Sonoran Desert. A late Wisconsin juniper-Joshua tree woodland gave way to a transitional early Holocene desertscrub with sparse Juniperus californica (California juniper) by 10,540 yr B.P. Important Sonoran Desert plants including Carnegiea gigantea (saguaro) and Encelia farinosa (brittle bush) were dominants. Riparian trees such as Acacia greggii (catclaw acacia), Prosopis velutina (velvet mesquite), and Cerdicium floridum (blue palo verde) grew on dry, south-facing slopes in a middle Holocene Sonoran desertscrub in a warm, wet summer climate with frequent winter freezes. Modern subtropical Sonoran desertscrub formed about 4000 yr B.P. as summer rainfall and winter freezes declined. Cercidium microphyllum (foothills palo verde), Sapium biloculare (Mexican jumping bean), Olneya tesota (ironwood) and Stenocereus thurberi (organ pipe cactus) became dominant as riparian trees retreated to wash habitats. The inferences of a latest Wisconsin/early Holocene summer monsoonal maximum by J. E. Kutzbach (1983), Modeling of Holocene climates. In “Late-Quaternary Environments of the United States,” Vol. 2, “The Holocene” (H. E. Wright, Ed.), pp. 271–277. Univ. of Minnesota Press, Minneapolis) are not supported for the Southwest. Apparently the persistence of late Wisconsin circulation patterns offset any increases in insolation.

Sediments began accumulating in nine mires on Barrington Tops, on the Northern Tablelands of New South Wales, before 11,000 yr B.P., and peat became common in the region by 8600 yr B.P. Sedimentation rates were low, but increased markedly about 3000 yr B.P. and again around 500 yr B.P. as a result of regional climatic change. A comparison of the results with other environmental data from the region suggests that conditions in the early Holocene were warmer and moister than at present, but that cooler and drier environments developed about 3000 yr B.P. In the last 500 yr a slight warming and either increased precipitation or cloudiness has become evident.

Pollen samples from the Arava travertines, dated to oxygen isotope stages 5 and 7, show relatively high arboreal pollen levels. These spectra are probably a result of an expansion of the Mediterranean maquis in Transjordan, which indicates periods of wetter climatic conditions. These periods probably represent humid fluctuations within stages 5 and 7.

Chironomid (midge) remains analyzed from an 8.95-m-long sediment core from Marion Lake reveal successional changes over the last 12,000 yr since deglaciation. A late-glacial Heterotrissocladius-dominated association characterizes the earliest sediments. Succeeding this community, at the onset of the Holocene, is a Tanytarsini-dominated assemblage. The transition between these communities occurs during a time of rapid climatic amelioration, preceding an early Holocene xerothermic interval. The late-glacial fossil fauna is suggestive of more northerly affinities. Similar sequences have been reported in late-glacial lake sediments elsewhere in North America and in Europe. The composite picture of these chironomid assemblages suggests the gradual retreat of a formerly widely distributed, cold stenothermous fauna. The response of the chironomid community accords well with paleoclimatic inferences based on pollen data at the lake. Subsequent postglacial changes are less pronounced and most are probably attributable to the gradual shallowing of the basin. Chironomid remains from shallow, weakly stratified lakes may yield valuable paleoclimatological data.