Late Quaternary Environmental Change Research Articles

Geochemical Characteristics of a Loess‐Soil Sequence in Central Kansas

AbstractThis study focuses on a Barton County loess‐soil section in central Kansas in an attempt to retrieve the geochemical signature of the late Quaternary environmental change in the arid‐semiarid region and provide a data base of loess geochemical characteristics in the Great Plains. The data indicate that the elements (expressed as oxides) of the windborne fraction (<63 µm) that are easily solubilized and lost from the soil by chemical weathering and leaching are relatively sensitive to soil‐forming processes, whereas the insoluble elements of that fraction are controlled primarily by the chemical composition of the parent material. The geochemical imprint of pedogenesis superimposed on that of the loess parent material can be distinguished by comparing the magnetic susceptibility signature with the Fe2O3/Al2O3 ratio. Based on the geochemical imprint and radiometric dates (14C and thermoluminescence), the Bignell Loess (8000–5000 yr) is poorly weathered and the Brady Soil (10 000–8000 yr) is strongly weathered. The Peoria Loess (20 000–10 000 yr) has neither a traceable leaching nor weathering marker, and the Gilman Canyon pedocomplex (35 000–20 000 yr) is strongly leached. The reddish pedocomplex (70 000–35 000 yr) is the most strongly weathered, probably due to stable land surface conditions in a mild climate, and the Barton sand (92 000–70 000 yr) seems to have been subjected to a moderate weathering. Within the exposed portion of the Loveland Loess (260 000–92 000 yr), weathering indices are inversely correlated with the carbonate content and the carbonate‐rich soils were developed under warm dry environments before 92 000, around 193 000, and before 260 000 yr. The data also show that the geochemical background of Fe2O3 and Al2O3 is high in two portions of the section: from the Brady Soil to the Gilman Canyon pedocomplex and from LL1 to LL2 within the Loveland Loess. The geochemical background of Fe2O3 and Al2O3 in the loess‐soil sequence might have been dictated by that of eolian sources.

The articulation of cultural processes and Late Quaternary environmental changes in Cisjordan.

The dynamics of Epipalaeolithic and Early Neolithic adaptations in the southern Levant from areas west of the Rift Valley are briefly described and evaluated against the backdrop of climatic changes. Taking account of recent advances in environmental studies and important revisions in the chronological framework of pollen diagrams from the Hula, a high degree of correlation between environmental and cultural developments is apparent. The variable nature of environmental changes and the mosaic of ecological zonation on human adaptive systems are stressed, with differentiation between : long-term incremental trends; sudden climatic changes; and predictable annual fluctuations about a mean. The nature and flexibility of the responses by communities to such external changes depended upon specific combinations of technological, social and ideological, psychological as well as idiosyncratic factors. Favourable niches alternately expanded or contracted. At times human adaptation systems in Cisjordan can be divided into two provinces, Mediterranean and Steppe/Desert ; at other times they included adjacent areas, such as Transjordan and the northern part of the Levantine corridor. A number of crises or "bottle-neck" situations, most resulting from environmental changes, are described which caused radical re-alignments in social and subsistence systems. It is against this backdrop, together with generally conservative social systems, that the transformation from foraging to plant and animal husbandry should be viewed.

The response of geomorphic systems to climatic and hydrological change during the Late Glacial and early Holocene in the humid and sub-humid tropics

Abstract Dated alluvial stratigraphies indicative of late Quaternary environmental change in the humid tropics have increased, but the database remains inadequate and the intensity and duration of wet-dry oscillations and responses of hillslopes and river systems remain poorly understood. Dry conditions at the Last Glacial Maximum were marked by semi-arid landforms with reduced stream activity. Large palaeofloods, valley-floor erosion, channel cutting and flood deposition occurred at the Pleistocene-Holocene transition after 13 000 BP. Distinctive floodplains and stratigraphies characterized by multiple shifts from lateral to vertical accretion were built initially over a period of nearly 2 ka after 9 500 BP during the early Holocene pluvial in Africa, Kalimantan and Amazonia during and after re-establishment of the lowland rainforests. Several wet-dry climatic oscillations followed in the mid-Holocene period and are marked by alluvial cut and fill sequences and by slightly thinner but coarse textured floodplain overbank sediments.

Geomorphic response to rapid climatic and hydrologic change during the late pleistocene and early holocene in the humid and sub-humid tropics

The data base concerning late Quaternary environmental change in the humid tropics is dependent on records from scattered sites; the intensity and duration of wet-dry oscillations remain speculative, and the responses of hillslopes and river systems are based on over-simplified models. However, available evidence indicates that prolonged aridity affected all but a few favoured core areas of equatorial climate after 20,000 BP, lasting 5–7 ka. Dry conditions at the LGM were marked by semi-arid landforms and reduced steam activity. Large palaeofloods occurred after 13,000 BE but dry conditions returned after 11,000 BP, before the early Holocene pluvial led to abundant sedimentation lasting nearly 2 ka after 9500 BP, in Africa, Amazonia and Australasia. Erosion (channel cutting) and flood deposition occurred at the Pleistocene-Holocene transition, followed by multiple shifts from lateral to vertical accretion (fill-cut episodes) during the early Holocene, while thick overbank deposits formed during the later Holocene. Re-establishment of the lowland rainforests was delayed until after 9000 BP in Africa, Australia and Brazil and several wet-dry oscillations followed in the mid Holocene period. Hillslope activity at the LGM was marked by local sediment transfers and fan formation; at the termination sediment fluxes increased rapidly, but mass movement probably peaked after 10,000 BP Sediment delivery to stream channels was not immediate and large sediment stores remain on the landscape today, many in areas of potential sensitivity of erosion.

Late Quaternary environmental change and human impact around Lake Bolac, western Victoria, Australia

AbstractThe late Quaternary history of the Lake Bolac region is reconstructed from sedimentary and pollen analysis of lake and swamp sequences and is supported by archaeological remains from lunette sediments. Freshwater deposits recovered from lake Turangmoroke appear to date from the last glacial period, when the vegetation was composed of herbfield and grassland. Subsequent dry conditions at the end of the Pleistocene caused the deflation of some accumulated sediments. On refilling, the lake had become saline. As moisture availability increased, casuarina woodland, dominated by Allocasuarina verticillata, became the regional vegetation cover. Domination by casuarina ended ca. 8000–7000 yr BP, probably as a result of rising saline ground‐water tables. Casuarinas were replaced to some degree by eucalypts, augmented by the development of a riverine Eucalyptus camaldulensis woodland. Swamp deposition commenced in the channel of neighbouring Fiery Creek at ca. 4000 yr BP, most likely as the result of a reduction in stream flow with decreased precipitation. Despite suggestions of significant impact on the vegetation by Aboriginal people from other sites in southeastern Australia, there is no evidence of any alteration here from periods of occupation dated to around 13000 yr BP and after 3500 yr BP. The period of European occupation, though, is marked by significant changes in fire patterns, reduced tree cover, loss of floristic diversity, increased erosion rates and salinity levels, and decreased water levels.

Books of Note

Abstract Abstract Critical Condition: Human Health and the Environment edited by Eric Chivian, Michael McCally, Howard Hu, and Andrew Haines; MIT Press, Cambridge, Mass., 1993; 244 pp., $15.95 paper Reviewed by Harold D. Foster. Late Quaternary Environmental Change: Physical and Human Perspectives by Martin Bell and Michael J. C. Walker; Longman Scientific and Technical, Essex, England, 1992; 273 pp., $43.95 paper Reviewed by Jeffrey A. McNeely. Environmental Economics: A Reader edited by Anil Markandya and Julie Robertson; St. Martin's Press, New York, 1992; $49.95 cloth, $19.95 paper Reviewed by Hadi Dowlatabadi.

Late Quaternary Environmental Change

Journal of Environmental QualityVolume 23, Issue 1 p. 213-214 Book Review Late Quaternary Environmental Change John Wiley & Sons, Inc., 605 Third Ave., New York, NY 10158. 1992. 273 p. ISBN 0-582-04514-2 Kerry H. Cook, Kerry H. Cook Dep. of Soil, Crop, and Atmospheric Sciences, Cornell University, Ithaca, NY, 14853Search for more papers by this author Kerry H. Cook, Kerry H. Cook Dep. of Soil, Crop, and Atmospheric Sciences, Cornell University, Ithaca, NY, 14853Search for more papers by this author First published: 01 January 1994 https://doi.org/10.2134/jeq1994.00472425002300010038xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume23, Issue1January‐February 1994Pages 213-214 RelatedInformation

Late Quaternary Environmental and Climatic Changes in Central Brazil

Paleoenvironmental changes dating back to 30,000 yr B.P. documented in a pollen record from central Brazil (lat. 19°S) permit the reconstruction of climatic changes related to shifts of the Antarctic polar fronts. The paleoclimatic inferences were obtained by a study of modern vegetation and pollen distribution, taking into account present-day climatic parameters. At 30,000 yr B.P. the climate must have been warmer and moister than today judging from the high amount of tree pollen taxa characteristic of floodplain forest. From 17,000 to 14,000 yr B.P. the climate was drier although tree pollen percentages were relatively high. After 12,000 yr B.P. Araucaria forest elements increased, suggesting a moister and cooler climate. The Araucaria forest disappeared during a short interval between 11,000 and 10,000 yr B.P. This could be related to the Younger Dryas event. At the beginning of the Holocene the climate became cool and moist again, as indicated by the reexpansion of the Araucaria forest. The latter was progressively replaced by a mesophytic semideciduous forest indicating warmer and drier climate after 8500 yr B.P. At 5000 yr B.P. an arid interval was followed by the expansion of mesophytic semideciduous forest elements.

PALHYDAF (Palaeohydrology in Africa) program: objectives, methods, major results

The PALHYDAF program aims to reconstruct the Late Quaternary (130 ka B.P. to Present) environmental and hydrological changes of northwest Africa, and to interpret them in terms of palaeoclimate for testing coupled atmospheric/ocean circulation models. Lacustrine sequences were obtained from closed basins which lie along two meridional transects: southern Tunisia-southern Niger, and Algeria-Mali. Particular attention is given to groundwater storage and periods of recharge of the aquifers. The chronological framework is based on 14C dates (conventional and AMS methods) and/or the Th/U disequilibrium method. In favourable cases (e.g. Mali), correlations can be made between the chronology of surface palaeohydrology and that of aquifer recharge. Various environmental markers (mineralogy, elemental chemistry, stable isotopes, biological remains) are used for palaeoenvironmental purposes. Quantitative estimates of palaeoclimatic variables (e.g. air humidity) may be attempted through the combination of geochemical and palaeobiological data. The major results already obtained are summarized for the following individual sectors: 1 — southern Tunisia. 1′ — northern Algeria. 2 — southern Algeria. 3 — northern Niger. 3′ — Mali. 4 — southern Niger. At the present stage of investigation, the following new inferences can be drown. • - One, or several humid episode(s) occurred in the northern Sahara between ≈ 150 and ≈ 75 ka B.P. Several factors suggest that these humid conditions also affected lower latitudes, although their southern extent cannot be given precisely at present. • - The previously postulated existence of large lakes at ≈20–35 ka B.P. is not confirmed. This time interval seems to coincide with raised water-tables, but not to a major humid phase. In all cases, the 14C chronologies obtained for the Late Pleistocene have to be checked by comparison with other dating methods (e.g. Th/U disequilibrium). • - After the arid period of the Last Glacial Maximum, the return of humid conditions occurred in two major steps, at ≥12 and ≈9.5-9 ka B.P. for both the southern and the northern Sahara.

Late quaternary environmental changes in eastern and central Australia, and their climatic interpretation

The march of environmental changes in eastern Australia, from the Last Interglacial to the Holocene, is reviewed. Palynologic evidence suggests that forest composition fluctuated substantially during Oxygen Isotope (OI) Substages 5a to 5e, but physical evidence for this period is as yet poorly defined. During OI Stage 3 and possibly part of 4, inland lakes were larger and the hydrologic balance was wetter than at any time since. Conditions were coldest, and dune activity was maximal throughout the continent, during OI Stage 2, but driest conditions as judged from lake levels occurred at the termination of the Pleistocene, when temperatures were rising rapidly. Lags between changes of boundary conditions and responses of natural systems are clearly seen in Holocene behaviour of coasts and reefs, and the effects of extreme events rather than climatic changes are seen in some sedimentary sequences. Establishment of the chronology of deposits older than about 35 ka, and forging links between the terrestrial and deep-sea records, are major challenges for future research.

The History of the Clanwilliam Cedar (Widdringtonia cederbergensis): Evidence from Pollen Analysis

SYNOPSIS It has been argued that the current “endangered” status of the endemic Clanwilliam cedar is a consequence of exploitation of the tree and changes in the fire regime which took place within the last two hundred years or so. In this paper, the results of a detailed palaeoecological analysis of two cores of organic sediment from vleis in the Cederberg are used to extend the documented history back to 14500 years ago. The demise of Widdringtonia cedarbergensis must be seen against a backdrop of late Quaternary environmental changes. It is argued that natural environmental changes, coupled with anthropogenic influences of both Khoisan and Khoikhoi, have also had significant effects on the distribution of the cedar. The Cederberg was not clothed in a closed-canopy cedar forest during the late Pleistocene and Holocene, although the tree appears to have been more widespread prior to 4000 years ago. The management implications of these findings are briefly introduced.

Late Quaternary environmental change in the Lake O'Hara region, Yoho National Park, British Columbia

Palaeoenvironmental reconstructions for the upper Cataract Brook Valley are derived from radiocarbon and tephra dated cores recovered from subalpine Lake O'Hara and alpine Opabin Lake located near the Continental Divide in the central Canadian Rocky Mountains. Late Quaternary vegetational and climatic changes are based on pollen and macrofossil data and are supplemented by preliminary diatom data. The postglacial colonizing vegetation prior to ca. 10,100 yr B.P. at Lake O'Hara and before ca. 8530 yr B.P. at Opabin Lake was a shrub herb community dominated by Artemisia, Gramineae and Alnus. Pioneering forests at both sites were composed of Pinus cf. albicaulis/flexilis and Abies with lesser abundances of Picea and Pinus cf. contorta. Timberline remained above the elevation of Opabin Lake, at least 90 m above modern timberline elevation, during the period ca. 8500 yr B.P. to ca. 3000 yr B.P. in response to warmer climatic conditions associated with restricted glacial activity. Forest compositions resembling the modern subalpine Picea-Abies forest had developed by the end of this period. The period ca. 3000 yr B.P. to present was marked by deteriorating climatic conditions associated with renewed glacial activity in the Opabin Cirque and declining timberlines to below the elevation of Opabin Lake. Glacigenic sediments in the Opabin record from the post-Bridge River (ca. 2350 yr B.P.) interval are associated with reduced diatom production and a change in dominant diatom taxa to those characteristic of turbid water conditions and unstable catchment areas.

Late Quaternary environmental changes inferred from small mammalian fauna, southern Africa

Relative changes in temperature are inferred from multivariate analysis of the relative abundance of rodents and insectivores represented in Late Quaternary deposits at nine sites in various regions of southern Africa. The major increase in temperature at the end of the Last Glacial Maximum is documented, and relative changes in temperature are calibrated for all sequences. The method of analysis provides an opportunity to correlate sequences from cave deposits which are beyond the range of conventional radio-carbon dating techniques.

Late quaternary environmental changes in the upper Las Vegas valley, Nevada

Five stratigraphic units and five soils of late Pleistocene to Holocene age crop out in dissected badlands on Corn Creek Flat, 30 km northwest of Las Vegas, Nevada, and at Tule Springs, nearer to Las Vegas. The record is dominantly fluvial but contains evidence of several moister, marsh-forming periods: the oldest (Unit B) dates perhaps to the middle Wisconsin, and the more widespread Unit D falls between 30,000 and 15,000 yr B.P. Unit D therefore correlates with pluvial maximum lacustrine deposits elsewhere in the Great Basin. Standing water was not of sufficient depth or extent during either period to form lake strandlines. Between 14,000 and 7200 yr B.P. (Unit E), standing surface water gradually decreased, a trend also apparent in Great Basin pluvial lake chronologies during the same period. Groundwater carbonate cementation and burrowing by cicadas (Cicadae) accompany the moist-phase units. After 7200 yr B.P., increased wind action, decreased biotic activity, and at least 25 m of water-table lowering accompanied widespread erosion of older fine-grained deposits. Based on pack-rat midden and pollen evidence, this coincides with major vegetation changes in the valley, from sagebrush-dominated steppe to lower Mohave desertscrub.

The quaternary stratigraphy of mount Etna, sicily: the effects of differing palaeoenvironments on styles of volcanism

Using recently published radiometric dates of important horizons within the Etna succession, correlations are proposed with the Late Quaternary biostratigraphies of the Italian mainland and the Mediterranean sea floor. This enables palaeoclimatic, palaeohydrological and palaeogeographical conditions on Etna to be established at stages in the volcano's evolution. It is argued that several major volcaniclastic suites were formed through the operation of processes that were under complex environmental, rather than simple volcanological control alone. In particular it is suggested that certain episodes of phreatomagmatic and laharic activity cannot be related to episodes of more evolved magma production, but rather to times during which the environment, height and configuration of Etna favoured the eruption and emplacement of these deposits. The authors reiterate their explanation of the formation of the Valle del Bove through processes of massive slope failure and indicate that conditions favouring this occurred at an appropriate stage in the history of the volcano. It is concluded that on active basaltic volcanoes, especially those like Etna which are also high mountains, the explanation of more violent phases requires the consideration of both internal volcanological and external environmental and morphological variables and that this is particularly important when its development has been set within the context of Late Quaternary environmental change. Finally the implications of these findings for the assessment of hazard are considered.

Paleo-Urban Development and Late Quaternary Environmental Change in the Akko Area

Des changements de niveau à l'holocène aussi bien que des mouvements régionaux et locaux déterminèrent la configuration de la côte nord d'Israël. Ces modifications influencèrent à leur tour l'emplacement et le type des établissements, en particulier d'Akko. Un essai de reconstruction du paléoenvironnement et de la paléogéographie est tenté ici à travers l'étude de la stratigraphie et de la nature des dépôts.

Terrestrial dunes, man and the late quaternary environment in southern Tasmania

Three source-bordering sand sheets that occur adjacent to the Derwent estuary and were occupied by Aboriginal groups have been examined. Two lunette sites in the Tasmanian Midlands, one occupied by Aboriginals the other not, have also been examined. Geomorphologic, stratigraphic, pedologic, and archaeologic evidence is used to decipher the broad sequence of late Quaternary environmental changes, and the effects of occupation. A broadly parallel sequence of changes is suggested by the two areas. The data suggest that relatively cold, dry, climatic conditions prevailed during the late Last Glacial Stage (25,000–10,000 B.P.), and that more humid conditions preceded and succeeded this period. The aeolian landforms and events compare with similar forms and events recorded from SE mainland Australia.

Evidence for a widespread late Pleistocene humid period in the Kalahari

THE nature and extent of late Quaternary environmental changes in the interior of southern Africa are obscure, in part because of a lack of absolutely dated sediments, and landforms of clear palaeoenvironmental significance. Here I present evidence to show that, during the period 17,000–15,000 BP, the Kalahari, now a semi-arid area with little or no surface drainage, was a region of widely distributed small lakes, as a result of a substantial increase in rainfall.