The question of what caused the late Quaternary extinction of the Rancholabrean fauna in the California glacial refugium is examined. In the absence of significant climatic and other natural environmental change, man was probably the principal agent of extinction in California. This extinction event marked the beginning of a long history of environmental impact in the area by humans.

A recent human campsite, occupied in 1973 by members of the Dassanetch tribe of northern Kenya, was observed from its creation through its subsequent burial in flood events 4 months later. The site was excavated as an archeological occurrence in the summer of 1974. Analyses of field and laboratory data yield a detailed picture of sedimentary structures, bone transport and burial, and site preservation in a well-documented depositional situation. Trampling by site occupants was apparently instrumental in burying much small bone prior to the flood events which acted on the site. About 30 cm of sediments accumulated on the site during four or five flood events. Individual sedimentary beds can be related to specific observed flood events in the drainage system. The ultimate preservation of the site as part of the region's archeological record would depend upon the interaction of sediment deflation and the varying local water table. Specific conditions which tend to preserve human sites in water-poor environments may consistently select seasonally biased vestiges of human settlement and economy.

The present Mediterranean climate of coastal California is unique in North America and reflects the interaction of several important synoptic controls, principally the North Pacific semipermanent anticyclone, and to a lesser extent the Aleutian low-pressure system and the cool California oceanic current. These synoptic climatic controls, key parts of the global air-sea circulation, were probably operative throughout late Quaternary time as shown by paleoecologic evidence. The thick accumulations of sediments in basins of offshore California indicate that while variable sedimentation regimes reflect changing climatic and oceanographic conditions, the Quaternary climate was probably semiarid as now, even during glacial maxima. Late Quaternary coastal dunes preserve former wind directions and show that prevailing late Quaternary winds were directionally equivalent to modern winds, which are controlled by the North Pacific anticyclone and by interactions between the North Pacific high and the interior basin low. These sand dunes contain buried, datable, carbonate-rich soils. Precipitation then, like the present rainfall regime, was not enough to leach the carbonates from the soils. Charcoal in buried dunes and soils shows that fire was environmentally important throughout the Quaternary, just as it is today. Fossil plants indicate that sclerophyllous vegetation and forest stands of conifers, adapted to a Mediterranean climate, were widely distributed during late Quaternary time. Fossil pollen in the Sierra Nevada indicates the influence of the North Pacific high. The historical precipitation record overlaps a late Holocene tree-ring record permitting extrapolation of the precipitation curve back nearly 600 years. Well-defined wet and dry trends in the precipitation pattern characterized this time span, and provide a possible analog to the earlier Holocene and Pleistocene precipitation regime. The paleoecologic record shows that the late Quaternary climate of coastal California was characterized by regimes similar to those prevailing today. The persistence of a Mediterranean climate in California during the last glaciation contrasts with dramatic climatic changes experienced in glaciated parts of North America. California thus was an Ice Age refugium for animals and cold-sensitive plants.

The aim of this paper is to present a summary of current knowledge about Quaternary climatic changes, sea level fluctuations, tectonic deformation, and volcanic activity in Chile. In the Andean highlands of the hyperarid desert, glaciers and lakes fluctuated repeatedly. Evidence of pluvial periods is not well documented in the marginal desert. On the contrary, pronounced climatic changes are recorded in semiarid Chile. In central Chile two or three major glacial advances have been identified, but they remained confined within the high Cordillera. In the longitudinal valley of the Lake Region geomorphic remnants of four glaciations have been described; 14C dates are available for the last glaciation. The glacial history of the Fjord Region is still obscure. Whether Pleistocene climatic changes in the northern and southern part of Chile were synchronous or not is a problem which requires further investigation. Sea level fluctuations along the Chilean coast are in part ascribed to glacio-eustatic effects. They left striking sets of step-like marine terraces in northern and central Chile. From a paleontologic point of view the Pleistocene corresponds to a pronounced move toward isolation and endemic development of the marine fauna. The Quaternary tectonic tendency seems to be toward extension and not compression expected as sea-floor spreading compensation. Normal faults limiting uplifted, downwarped, and tilted blocks are common. Folds are rarely found. Northern Chile is characterized by an imposing chain of about 600 stratovolcanoes. They rest on Tertiary ignimbrites which cover the altiplano. Quartz-bearing latite-andesites are predominant. Present volcanic activity is sporadic and weak. South of a conspicuous gap between 27 and 33°S, Quaternary volcanism reappears in the high Cordillera, and many volcanoes have erupted violently within historic times. Rocks are fundamentally andesite or basaltic andesite. Poorly sorted ashes including pumice clasts in the Central Valley south of Santiago are interpreted as volcanic mudflows of late Pleistocene age.

A Pleistocene drift sequence in hummocky terrain along part of the southern Avalon Peninsula of Newfoundland is interpreted to comprise complexly interrelated lodgement till, melt-out till, flow till, supraglacial and proglacial outwash, and supraglacial rhythmites. The gray and tan melt-out tills are stacked in imbricate fashion, giving rise to exceptionally thick stratigraphic sections. Contacts between melt-out tills are interpreted as remnants of shear planes because they are sharp, they dip in the up-ice direction, and they converge toward valley margins. Overlying flow tills interdigitate with supraglacial outwash. The drift sequence was deposited during a single episode of glaciation, rather than by repeated glacier advance, as previously proposed. It is the product of thrusting of englacial debris along ice-marginal shear planes, subsequent melting-out of englacial debris, and formation of supraglacial flow till and outwash. Preservation of this sequence probably is due to high content of englacial debris within the Wisconsinan ice. The sedimentary, glacitectonic, and morphologic features of this sequence are similar to those found at the margins of certain Arctic glaciers of subpolar thermal regime which have recently been the subject of Pleistocene glacial sedimentation models for west-central Canada and Great Britain. Recognition of these distinct elements indicates wisconsinan glacier lobes were of the cold Arctic type in southeastern Newfoundland. Alternative explanations for this sequence, such as deposition by glaciers of temperate thermal regime or by surging glaciers, are discounted. Because the features described here are complex and difficult to recognize, they may be more widespread in Pleistocene drift than has previously been interpreted.

In the Camp Century core, the difference in oxygen isotope ratio between Wisconsin and Holocene ice seems too large to be purely a climatic effect. A more likely interpretation is that the Wisconsin ice originated at an elevation of at least 500 m above the present station. Total gas content measurements on the core suggest that the elevation difference was about 1300 m. These results are inconsistent with the present ice flow pattern. Three hypotheses are considered: (1) The Wisconsin ice originated near the crest of a high ridge connecting the Greenland ice sheet with an ice sheet on Ellesmere Island. (2) The Wisconsin flow pattern was similar to the present one but ice was much thicker and the ice margin considerably in advance of its present position. (3) The Wisconsin ice originated near the main Greenland ice divide whereas the Holocene ice originates within 50 km of the station. Glacial-geological data are sparse but do not appear to support the first hypothesis, while the uplift data have been interpreted in two widely different ways. The second hypothesis might explain the oxygen isotope values but not the gas content measurements. The third hypothesis is thus considered the most likely one. Differences between Wisconsin and Holocene flow patterns might result from changes in positions of the ice margins as a consequence of lowered sea level in the Wisconsin.

Quaternary deposits on the Pacific slope of Washington range in age from the earliest known interglaciation, the Alderton, through the Holocene. Pollen stratigraphy of these deposits is represented by 12 major pollen zones and is ostensibly continuous through Zone 8 over more than 47,000 radiocarbon yr. Before this, the stratigraphy is discontinuous and the chronology less certain. Environments over the time span of the deposits are reconstructed by the comparison of fossil and modern pollen assemblages and the use of relevant meteorological data. The Alderton Interglaciation is characterized by forests of Douglas fir (Pseudotsuga menziesii), alder (Alnus), and fir (Abies). During the next younger interglaciation, the Puyallup, forests were mostly of pine, apparently lodgepole (Pinus contorta), except midway in the interval when fir, western hemlock (Tsuga heterophylla), and Douglas fir temporarily replaced much of the pine. Vegetation outside the limits of Salmon Springs ice (>47,00034,000 yr BP) varied chiefly between park tundra and forests of western hemlock, spruce (Picea), and pine. The Salmon Springs nonglacial interval at the type locality records early park tundra followed by forests of pine and of fir. During the Olympia Interglaciation (34,000–28,000 yr BP), pine invaded the Puget Lowland, whereas western hemlock and spruce became manifest on the Olympic Peninsula. Park tundra was widespread during the Fraser Glaciation (28,000–10,000 yr BP) with pine becoming more important from about 15,000 to 10,000 yr BP. Holocene vegetation consisted first of open communities of Douglas fir and alder; later, closed forests succeeded, formed principally of western hemlock on the Olympic Peninsula and of western hemlock and Douglas fir in the Puget Lowland. Over the length of the reconstructed environmental record, climate shifted between cool and humid or relatively warm, semihumid forest types and cold, relatively dry tundra or park tundra types. During times of glaciation, average July temperatures are estimated to have been at least 7°C lower than today. Only during the Alderton Interglaciation and during the Holocene were temperatures higher for protracted periods than at present.

This paper summarizes the subsurface geology of the recent (both Holocene and latest Pleistocene) formations and the buried topography beneath them in and around Tokyo Bay, the type area of the late Quaternary in Japan. Buried abrasion platforms in the buried topography are classified into upper (ca. 0 to −10 m high) and lower (ca. −20 to −40 m) platforms; upper and lower buried river terraces are also distinguished, and are correlated to the subaerial late Pleistocene terraces of Tc1 and Tc2, respectively. A buried valley system is elucidated, of which the trunk valley floor reaches −70 m in Tokyo and emerges into a flat surface at the shelf edge in the entrance to Tokyo Bay. Approximate dates for these geomorphic surfaces are given. The height of sea level contemporaneous with the buried valley floor (ca. 20,000–15,000 yr BP) is estimated at about −135 m. The recent formations are divided into two members, upper and lower, by a middle sand bed, in addition to the lowest buried valley floor gravel. The lower member, which is composed of brackish to marine deposits of complicated lithofacies, was accumulated in narrow drowned valleys during the early stage of the Yurakucho (Flandrian) transgression. The middle sand bed is the foreset bed of deltas, which was formed during a slight regression between ca. 11,000 and 10,000 yr BP. The upper member, which consists mainly of widespread homogeneous marine clay and deltaic sand, was accumulated in a wide bay and its embayments during the late stage of the Yurakucho transgression and the following stage of a relatively stable sea level.

A fine exposure of perennially frozen ice-rich silt and associated flora and vertebrate fauna of late-Quaternary age exists at Mamontova Gora along the Aldan River in central Yakutia, Siberia, U.S.S.R. The silt deposit caps a 50-m-high terrace and consists of three units. An upper layer 1–2 m thick overlies a 10–15-m-thick brownish to black silt layer. The lower silt layer is greenish to gray and about 15 m thick. All the silt is well sorted with 60% of the particles falling between 0.005 and 0.5 mm in diameter and is generally chemically and mineralogically homogeneous. The middle unit contains may extinct vertebrate mammal remains and ice wedges. The lower unit contains little vegetation and no ice wedges. The silt is widespread and exists as a loamy blanket on terraces at various elevations on both sides of the lower Aldan River. The origin of the silt blanket of late-Quaternary age in central Yakutia has long been controversial. Various hypotheses have been suggested, including lacustrine and alluvial, as well as frost-action origins. It is sometimes referred to as loess-like loam. Péwé believes the silt at Mamontova Gora is loess, some of which has been retransported very short distances by water. The silt probably was blown from wide, braided, unvegetated flood plains of rivers draining nearby glaciers. The silt deposits are late Quaternary in age and probably associated with the Maximum glaciation (Samarov) and Sartan and Syryan glaciations of Wisconsinan age. On the basis of biostratigraphy, 10 radiocarbon dates, and their relation to the nearby glacial record, it is felt that the upper unit at Mamontova Gora is Holocene and the middle unit is Wisconsinan. The youngest date available from the middle unit at this particular location is 26,000 years. Dates greater than 56,000 years were obtained in the lower part of the middle unit. The lower unit is definitely beyond the range of radiocarbon dating and probably is older than the last interglacial. The sediment, fauna, ice wedges, stratigraphy, and age of perennially frozen slit deposits in central Alaska are remarkably similar to those of the deposits exposed in central Yakutia. Both areas consist of unglaciated rolling lowlands and river terraces surrounded by high mountains that were extensively glaciated in Pleistocene time. The glaciers extended from the high mountains to the edges of the ranges. In both regions, extensively braided, silt-charged rivers drained the mountains and flowed through the lowlands on their way to the sea. It follows that there should be a similar late-Quaternary history.

Pollen preserved in a peat deposit from a large swamp, the Old Field in the Mississippi River Valley near Advance, Missouri, records radiocarbon-dated vegetation changes between 9000 and about 3000 years ago. The principal feature of both the percentage and influx pollen diagrams is the replacement of arboreal pollen, primarily Quercus, Fraxinus, and Cephalanthus, with Gramineae and NAP between 8700 and 5000 years BP. This vegetation shift is interpreted as reflecting a decrease in the extent of the Old Field swamp and its associated bottomland forest species along with the expansion of a grass-dominated herb community, as a result of a reduction in available ground water. The desiccation of the swamp during this period indicates a reduction in precipitation within the ground-water source area and a shift to a drier climate in the southern Midwest. The pollen suggests that the lowest water levels and driest climate in southeastern Missouri lasted from 8700 to 6500 years BP, at which time there is a partial reappearance of swamp species. Relatively dry conditions, however, continued until at least 5000 years BP. Although pollen influx data are lacking from the upper part of the profile, the relative pollen frequencies suggest an increase in trees after 5000 BP. The replacement of the arboreal vegetation by grasses and herbs between 8700 and 5000 years BP reflects the period of maximum expansion of the Prairie Peninsula in southeastern Missouri. The Old Field swamp provides the first pollen evidence that the vegetational changes along the southern border of the Prairie Peninsula were chronologically similar to those on the northern and northeastern margins.

Pollen contained in 22 fossil packrat middens from the Sonoran Desert provides a complementary, but differing, view of the paleoenvironment from that derived by analysis of the associated plant macrofossils. The regional component of the pollen data is in sharp contrast to the locally oriented macrofossils. A total of 84 macrofossil taxa and 47 pollen taxa were identified; only 18 taxa were common to both. The low Index of Similarity, 0.4, indicates that the two sources of fossil information are providing different sets of paleobotanical data. When combined with plant macrofossils and good radiocarbon dating control, the pollen spectra derived from fossil middens are compatable with other paleoenvironmental sequences.

A deep-sea core over 16 m long from the crestal area of the Mediterranean Ridge has been investigated with different techniques, including quantitative micropaleontology, stable isotopes (measured on the epipelagic species Globigerinoides ruber and on the mesopelagic species Globorotalia inflata), and clay mineralogy. The resulting record of climatic fluctuations can be cross correlated to other Mediterranean cores by means of isochronous lithologies (tephra layers and sapropels). The climatic record of the Mediterranean is similar in character, phase, and chronology to the records investigated in the equatorial Pacific and in the Caribbean. Isotope stages 1 to 17 have been recognized. Cyclically repeated stagnant cycles resulting in sapropel deposition complicate both the isotopic and the faunal signal. The isotopic investigations reveal that the temperature change in the surface layers of the eastern Mediterranean was no greater than 8°C in the late “glacial” Pleistocene. The chronostratigraphic and biostratigraphic interpretation of Core KS09 indicate that the mean sedimentation rate was 2.4 cm/1000 years, a value very close to the 2.5 cm/1000 years calculated for the entire Quaternary section at DSDP Site 125, also located in the crestal area of the Mediterranean Ridge in the Ionian Basin. The base of KS09 is likely to be very close to the Brunhes/Matuyama boundary dated at 0.7 my.

By mapping the data from 62 radiocarbon-dated pollen diagrams, this paper illustrates the Holocene history of four major vegetational regions in northeastern North America. Isopoll maps, difference maps, and isochrone maps are used in order to examine the changing patterns within the data set and to study broad-scale and long-term vegetational dynamics. Isopoll maps show the distributions of spruce (Picea), pine (Pinus), oak (Quercus), herb (nonarboreal pollen groups excluding Cyperaceae), and birch + maple + beech + hemlock (Betula, Acer, Fagus, Tsuga) pollen at specified times from 11,000 BP to present. Difference maps were constructed by subtracting successive isopoll maps and illustrate the changing patterns of pollen abundances from one time to the next. The isochrone maps portray the movement of ecotones and range limits by showing their positions at a sequence of times during the Holocene. After 11,000 BP, the broad region over which spruce pollen had dominated progressively shrank as the boreal forest zone was compressed between the retreating ice margin and the rapidly westward and northward expanding region where pine was the predominant pollen type. Simultaneously, the oak-pollen-dominated deciduous forest moved up from the south and the prairie expanded eastward. By 7000 BP, the prairie had attained its maximum eastward extent with the period of its most rapid expansion evident between 10,000 and 9000 BP. Many of the trends of the early Holocene were reversed after 7000 BP with the prairie retreating westward and the boreal and other zones edging southward. In the last 500 years, man's impact on the vegetation is clearly visible, especially in the greatly expanded region dominated by herb pollen. The large scale changes before 7000 BP probably reflect shifts in the macroclimatic patterns that were themselves being modified by the retreat and disintegration of the Laurentide ice sheet. Subsequent changes in the pollen and vegetation were less dramatic than those of the early Holocene.

In the equatorial Pacific, between the Galapagos Islands and the coast of South America, two kinds of upwelling of oceanic waters occur. One is related to coastal upwelling and the other to surfacing of the Equatorial Undercurrent. Both of those processes are associated with the development of the southeast trade winds blowing in this area. Coastal upwelling is increased when the trade winds are intensified, and the surfacing of the Equatorial Undercurrent occurs when the trades weaken. The development of coastal upwelling and the surfacing of the Equatorial Undercurrent are inferred from the radiolarian assemblages in the sediments. The abundance of quartz, opal, and radiolarian assemblages in the deep-sea sediments of this area, as well as the distance from the sample locations to land and to the quartz source, is correlated with the intensity of the trade winds (in February and August) through multiple regression analysis. The chronostratigraphy of core V19-29 (3°35′S, 83°56′W), used in this study, is inferred on basis of its δ180 record. During the last 75,000 years, the fluctuations in intensity of the trade winds have been concurrent with or preceded the fluctuations in the amount of ice stored on the continents. In general, the wind velocity of the winter trades has been intensified during cool climatic stages of the earth (δ180 stages 4 and 2) and they have been relaxed during warm stages (δ180 stages 3 and 1). Seasonal contrast of the trade winds has also fluctuated within time, having been relatively high during the upper part of δ180 stage 3.

Pollen analysis of two radiocarbon-dated cores provides a history of Wyrie Swamp and the surrounding vegetation, and the result compares with other palynological data from southeastern South Australia. Eucalypt (Eucalyptus) forest or woodland with a scrub understory was the major element before about 50,000 years BP, between ca. 40,000 and 30,000 BP, and after ca. 11,000 BP. More open woodland prevailed between ca. 50,000 and 40,000 BP, and between ca. 26,000 and 11,000 BP. Casuarina stricta, common on sand dunes, migrated to the area about 10,500 years ago and remained as a dominant species until the time of European settlement at about 1840 ad . Postglacial expansion of this species implies that the climate since 10,500 years ago has been warmer than in the preceding period. It probably was drier during the period from 50,000 to 10,500 BP than in the Holocene. The driest period was from 26,000 to 11,000 BP, perhaps corresponding to the time of the last glaciation in Australia. The site is archaeologically important, as a number of wood and stone artifacts that date between 10,200 and 8000 BP have been recovered from the swamp sediments.

Global atmospheric and oceanic circulation effects of expansion of continental ice sheets initiated upwelling in the western equatorial Pacific and simultaneously intensified upwelling in the eastern equatorial Pacific; contraction of the ice sheets reversed the process. Published Pleistocene paleoclimatic stratigraphies correlated across the entire equatorial Pacific exhibit eight such cycles in the Brünhes epoch. The extrapolated chronostratigraphies for the equatorial Pacific compare favorably with published paleoclimatic schemes for the southeastern, eastern, and northern Pacific Ocean. The Southern Ocean record exhibits fewer, and possibly also consistently older, climatic variations. A time progression or lack of synchrony of marine Pleistocene climatic events is not inconsistent with modified “Milankovitch” hypotheses, such as that involving Antarctic ice-sheet instability.

The African continent has afforded a wealth of evidence bearing on the early evolution of Hominidae and the development of capacities for culture. However, until recently there has been scant documentation of the time of dispersal of hominids from tropical into north temperate latitudes. Human populations were certainly well established in Europe by Mindel Glacial times, rather less than 0.7 my ago, to judge from known occupation places in France and Hungary. Recently several localities in southern France and southern Spain have afforded artifactual evidence to suggest the presence of human populations in the preceding Cromerian interglacial, and even very probably in the preceding glacial stage, the “Gunz” (of authors). The identity of these first Europeans still remains unknown.