Early Holocene

Pollen and high-resolution charcoal data from Bluff Lake and Crater Lake, California, indicate similar changes in climate, vegetation and fire history during the last 15 500 years. Pollen data at Bluff Lake suggest that the vegetation between c. 15 500 and 13 100 cal. BP consisted of subalpine parkland with scattered Pinus and Abies. After 13 100 cal. BP a relatively closed forest of P. monticola, P. contorta and Abies developed, and fire-event frequency was low. The inferred climate then was cooler and wetter than present. Pinus and Quercus vaccinifolia dominated at both sites during the early Holocene, when conditions were warm and dry. As climate became wetter and cooler in the late Holocene, Abies spp. at both sites and Tsuga mertensiana at Crater Lake increased in importance, displacing Pinus and Quercus. The two lake records have similar trends in fire history, with high event frequencies at c. 8400, 4000 and 1000 cal. BP and low values at c. 4800 cal. BP. The fire and vegetation history at both sites suggests a similar response to large-scale changes in climate during the Holocene.

Landslide-dammed lakes that form upstream of large-scale rockslide-avalanches ( = sturzstroms) present an enormous potential hazard to downstream areas. Such failures are recorded in the Early Holocene sediments of Upper Lake Constance (Germany) by the presence of two clastic layers that were emplaced around 9400 cal. YBP. The sedimentology of these layers contrasts sharply with the typical Late Glacial and Holocene lacustrine sediments present beneath the floor of the lake. Sedimentary structures and the magnetic fabric of these clastic deposits strongly suggest that they were emplaced by hyperpycnal underflows related to catastrophic floods that entered the lake from the Rhine River. From stratigraphic and geologic data, it is inferred that the hyperpycnite deposits are directly related to the failure of two sturzstrom dams and the draining of the dammed lakes that developed upstream from them. These lakes were dammed by the Flims and the Tamins sturzstrom deposits, respectively. Sedimentologic data from Lake Constance indicate that the two successive events occurred within a very short time interval, probably not exceeding several years. Consequently, these lacustrine deposits provide essential information about the morphogenic evolution of the Rhine River valley during the Early Holocene and about the sturzstrom events that occurred during the same time interval. D

A 9000-year carbonate-rich sediment sequence from a small hard-water lake in northernmost Sweden was studied by means of multi-component stable carbon isotope analysis. Radiocarbon dating of different sediment fractions provides chronologic control and reveals a rather constant hard-water effect through time, suggesting that the lake has remained hydrologically open throughout the Holocene. Successive depletion of 13 C in fine-grained calcite and carbonate shells during the early Holocene correlate with a change in catchment vegetation from pioneer herb communities to boreal forest. The vegetational change and associated soil development likely gave rise to an increased supply of 13 C-depleted carbon dioxide in groundwater recharging the lake. This process is therefore believed to be the main cause of decreasing values of 13 C in dissolved inorganic carbon of the lake and thereby in limnic carbonates. Strongly 13 C-depleted sedimentary organic matter may be related to enhanced kinetic fractionation during photosynthetic assimilation by means of proton pumping in Characean algae. This interpretation is supported by a substantial offset between 13 C of DIC as recorded by mollusc shells and 13 C of fine-grained calcite.

Coral species composition of drilled cores from emergent bank reefs, and coral cover of the surface of old and living reefs located along the coast of the state of Bahia, Eastern Brazil, revealed that there is a marked change in the occurrence of the major building coral species in different time intervals of the reef structure, as well as in the living surface of reefs located in two different geographical sites. Holocene core sections from two reef areas (12°40 0 S-38°00 0 W and 18°00 0 S-39°00 0 W) have as major reef builders, on its topmost core interval (3 to 4 ky old), the endemic coral Mussismilia braziliensis Verrill, 1868, which also dominate on the 2.5-3.5 ky old surfaces of truncated reef tops. At the base of the cores (the 2 m lower interval, older than 4 ky BP), another endemic coral Mussismilia harttii Verrill, 1868 is the dominant reef component. The relative abundance of M. braziliensis on the living surfaces of shallow reefs from both areas, shows that in the southern area, it is up to 98% on reefs located 60 km off the coast, in depths between 3 and 4 m, but do not exceed 1.3% on the surface of the northern reefs located 1-2 km off the coast in depths 4-5 m. The Holocene falling sea level that occurred along the coast of Brazil since 5.1 ky BP, causes an increasing runoff into the area of coastal reefs. This phenomenon may have affected the nearshore reef building fauna, replacing a more susceptive coral fauna with one better adapted to low light levels and higher sediment influx. The high turbidity associated with early Holocene shelf flooding, should also be responsible for the absence of M. braziliensis during the initial stages of reef buildup in Brazil. At the present time, the rapidly increasing human pressure, due to changes in land uses of the coastal zone (increasing sedimentation rate, nutrification of coastal waters, industrial pollution) and underwater practices, such as overfishing and an intense tourism, is aggravating the recovery capacity of this already naturally threatened coral community. If this situation coupled with increasing sea surface temperature persists, modern coral reef growth, in Brazil cannot be maintained and the major reef building coral species of the reefs in Bahia, a remnant endemic coral fauna will very soon appear in the list of endangered species.

In order to investigate the potential role of vegetation changes in megafaunal extinctions during the later part of the last glacial stage and early Holocene (42e10 ka BP), the palaeovegetation of northern Eurasia and Alaska was simulated using the LPJ-GUESS dynamic vegetation model. Palaeoclimatic driving data were derived from simulations made for 22 time slices using the Hadley Centre Unified Model. Modelled annual net primary productivity (aNPP) of a series of plant functional types (PFTs) is mapped for selected time slices and summarised for major geographical regions for all time slices. Strong canonical correlations are demonstrated between model outputs and pollen data compiled for the same period and region. Simulated aNPP values, especially for tree PFTs and for a mesophilous herb PFT, provide evidence of the structure and productivity of last glacial vegetation. The mesophilous herb PFT aNPP is higher in many areas during the glacial than at present or during the early Holocene. Glacial stage vegetation, whilst open and largely treeless in much of Europe, thus had a higher capacity to support large vertebrate herbivore populations than did early Holocene vegetation. A marked and rapid decrease in aNPP of mesophilous herbs began shortly after the Last Glacial Maximum, especially in western Eurasia. This is likely implicated in extinction of several large herbivorous mammals during the latter part of the glacial stage and the transition to the Holocene.

Given the difficulty of separating the three Picea species—P. glauca, P. mariana, and P. rubens (white, black, and red spruce)—in the pollen record, little is known about their unique histories in eastern North America following deglaciation. Here we report the first use of a classification tree analysis (CART) to distinguish pollen grains of these species. It was successfully applied to fossil pollen from eight sites in Maine and one in Massachusetts. We focused on the late glacial/early Holocene (14,000 to 8000 cal yr B.P.) and the late Holocene (1400 cal yr B.P. to present)—the two key periods since deglaciation when Picea has been abundant in the region. The result shows a shift from a Picea forest of P. glauca and P. mariana in the late glacial to a forest of P. rubens and P. mariana in the late Holocene. The small number of P. rubens grains identified from the late glacial/early Holocene samples…

A 9000 cal. year record of geochemistry was analysed in a sediment core obtained from a Swiss alpine hard-water lake (1937 m a.s.l.) that is located at the present-day tree-line. Geochemical stratigraphies are compared to changes in mineralogy, grain-size, pollen, and macrofossil records. This allows the reconstruction of the effects of changes in vegetation and of 3500 years of land-use in the catchment area on sediment geochemistry. Using principal component analysis, two major geochemical groups are distinguished: (i) Changes in concentrations of Rb, Ti, Zr, Fe, As, and Pb are closely related to corresponding changes in the concentrations of quartz and clay. They are thus considered to represent the silicate fraction which shows an increase from the oldest to the youngest core section. (ii) In contrast, Ca and Sr concentrations are positively correlated with changes in silt, sand, and calcite. They are therefore considered to represent the carbonate fraction which gradually decreased. Based on constrained cluster analysis, the core is divided into two major zones. The oldest zone (A; 9000-6400 cal. BP) is characterised by high concentrations of detrital carbonates. The more open catchment vegetation at that time promoted the physical weathering of these carbonates. The second major zone (B, 6400 cal. BP-1996 AD) is divided into four subsections with boundaries at ca. 3500, 2400, and 160 cal. BP. The lower part of this zone, B1, is characterized by a gradual decrease in the carbonate-silt fraction and a pronounced increase in the silicate-clay fraction. This is concurrent with the expansion of Picea in the catchment area, which probably stabilized the soil. The middle part, B2 and B3 (3500-160 cal. BP), comprises pronounced fluctuations in all elements, especially Ca, Sr, Mn, and Rb, but also in clay and silt. These changes are related to varying intensities of alpine farming. In the same section, Mn/Fe ratios are highly variable, suggesting changes in the mixing regime of the lake with phases of anoxic bottom water. The uppermost section, B4 (since 160 cal. BP), is characterized by a steep decline in the silicate fraction and an increase in Ca and Sr. Despite the decrease in the silicate fraction, Pb increases, due to elevated atmospheric input resulting from early metal pollution, are masked by the high natural variability. Generally, changes in vegetation, which correspond to climate changes in the early Holocene and to human activities since ca. 3700 cal. BP, are the controlling factor for variations in the geochemical composition of the sediment of Sägistalsee. This is the sixth in a series of eight papers published in this special issue dedicated to the palaeolimnology of Sägistalsee. Drs. André F. Lotter and H. John B. Birks were the guest editors of this issue.

We use the stratigraphy of floodplains on Alaska's North Slope to describe how tundra watersheds responded to climate changes over the last 15,000 calibrated years BP (15 cal ka BP). Two episodes of extremely rapid floodplain alluviation occurred during the PleistoceneeHolocene transition, one between 14 and 12.8 cal ka BP and the other between 11.5 and 9.5 cal ka BP. These aggradation episodes coincided with periods of warming in summer when cottonwood (Populus balsamifera L.) expanded its range, peatlands became established, and widespread thermokarst occurred. The two aggradation episodes were separated by a period of floodplain incision during the Younger Dryas under cooler and possibly drier conditions. At times of increasing summer warmth, melting permafrost and enhanced precipitation probably triggered widespread mass wasting on hillslopes that overwhelmed the capacity of streams to transport sediment downstream, and rapid floodplain aggradation resulted. After peatlands became widespread in the early Holocene, rivers slowly incised their valley fills. Because major pulses of sediment input were limited to times of rapid thaw and increasing moisture, many floodplains on the North Slope have been effectively decoupled from upstream hillslopes for much of the past 15,000 years. Our findings: (a) confirm the sensitivity of arctic watersheds to rapid warming in summer, (b) emphasize the importance of hillslope mass wasting in landscape-scale responses to climate change, and (c) suggest that the presence of peatland on this arctic landscape today has raised its geomorphic response threshold to climate warming compared to what it was 14,000 years ago.

Studies of cultural artifacts and faunal remains from European Upper Paleolithic and Mesolithic sites indicate a shift in hunter gatherer subsistence strategies, involving an intensification and diversification of resource exploitation relative to earlier foragers during the Tardiglacial and Postglacial periods. This trend has been recognized as well through the analysis of non-pathological skeletal adaptations of the upper limbs of European Upper Paleolithic human fossils. These paleoanthropological studies of adaptive bone modeling also raise the question of female use of throwing-based weapon technology in the Upper Paleolithic. Here, we studied another type of osteological marker of activity, enthesopathies, of the upper limb remains of 37 European Upper Paleolithic and Mesolithic human fossils, with the goal of testing two hypotheses: 1) that activity levels were heightened at the end of Upper Paleolithic and into the Mesolithic relative to earlier foragers of the Gravettian, and 2) that there was an absence of a marked sexual division of labor in European hunter-gatherers during this time span. Our results are consistent with the first hypothesis; upper limb enthesopathies are significantly less frequent in the Gravettian group, but raise doubts about the second hypothesis. Four males exhibit lesions that can be confidently associated with throwing activities, while no females exhibit such lesions.

Occupied from ca. 7040 B.C. to A.D. 1400, the Eel Point Site (CA-SCLI-43) on San Clemente Island, California represents one of the longest sequences of near-continuous marine resource exploitation on the west coast of North America. Faunal remains suggest transitions from heavy exploitation of fur seals and sea lions during the early Holocene, to increased hunting of cetaceans at mid-Holocene, to a focus on sea otters and fish during the late Holocene. These trends are consistent with patterns of overexploitation and economic intensification on the California and Oregon mainland, but they also suggest watercraft-based hunting earlier on the island than elsewhere. Fur seal and sea lion bones mainly represent females and juveniles, indicating that exploitation of island rookeries was guided more by self-interest than by principles of game conservation. Two intervals of temporary site abandonment, ca. 6150–3970 B.C. and A.D. 1020–1400, were both followed by periods of increased marine mammal exploitation and may reflect intervals during which marine mammal populations rebounded. Broad-scale diachronic trends in the zooarchaeological remains do not correlate with flux in paleo-sea temperatures and are best interpreted as products of overhunting and increased use of watercraft over time.

Late Quaternary paleoclimatic changes in the Levant are difficult to extract from carbonate oxygen isotope records partly because the factors controlling the terrestrial d 18 O signals are not fully understood in this region characterized by sharp climatic gradients. Here, we address this purpose by presenting the first 14 C-dated isotope record from the northern Levant. The record is based on oxygen isotopes from ostracod shells from lacustrine-palustrine deposits accumulated in a small karstic, hydrologically open basin (Yammoû neh), located on the eastern flank of Mount Lebanon. We have first constructed a composite isotopic record obtained from three different ostracod taxa. This yields an oxygen isotope record of ostracods (d ost) related to the most widespread species (Ilyocypris inermis), and converted to d 18 O values coeval with calcite precipitated in equilibrium (d C) with the lake water (d L). As with other records from the Mediterranean region, the Yammoû neh profile shows maximum and minimum d C values during the LGM and the early Holocene, respectively, and a slight late Holocene increase. In order to discuss the potential causes of the observed d 18 O values fluctuations (e.g., changes in the isotopic composition of the moisture source, temperature, precipitation minus evaporation (P-E) balance, or atmospheric circulation), we tentatively reconstruct the lake water isotope composition by correcting the d C values for lake water temperature using regional paleotemperature estimates. Inferred d L values were then corrected for the isotopic composition of the Eastern Mediterranean sea surface water (the moisture source) derived from planktonic foraminifera d 18 O values corrected for alkenone-based sea surface temperature. Our study suggests that Holocene d L fluctuations are primarily linked to changes in the sea surface water composition (source effect) amplified by enhanced inland rainfall during the early Holocene. During the LGM, low d L values at Yammoû neh are likely due to the ground-temperature effect on the rainfall isotope composition, possibly associated with a steeper altitudinal thermal gradient inland, and with changes in air mass trajectories over the Mediterranean Sea.

Holocene sediments from a 9 m high outcrop at the Gangyasang Qu's entry into Lake Nam Co, on the south-eastern Tibetan Plateau, were studied in a multiproxy approach. The lowermost part of the section is of early Holocene age and consists of varved sediments deposited in a proglacial lake. Geomorphological investigations of fossil beach ridges and fossil cliff lines in the littoral zone of Nam Co indicate a late Pleistocene lake level high of 29 m above the present level. A warming is visible in ostracode-rich silts deposited after 9.6 ka BP. An ostracode-based transfer function estimates a lake level 28 m higher than today from this time until about 5.2 ka BP. A late Pleistocene lake level high was accompanied by an increase in lake size, causing Nam Co to overflow into the lower course of Gangyasang Qu, where a bay with slack-water conditions formed. Between 4.2 and 1.3 ka BP the lake level was approximately 10 m higher than today. The progradation of the Gangyasang Qu delta into Nam Co and the decreasing lake level shifted the study site into a fluvio-lacustrine environment. The sandy character and relatively low numbers of ostracode valves in the topmost sediments indicate increased fluvial activity, possibly due to a temporary increase in flood frequency. This facies lasted at least until 1.3 ka BP, when the lake level of Nam Co dropped again and the river incised more than 10 m into the underlying fluvio-lacustrine and lacustrine sediments.

Temporal and spatial changes in glacier cover throughout the Late Quaternary in Tibet and the bordering mountains are poorly defined because of the inaccessibility and vastness of the region, and the lack of numerical dating. To help reconstruct the timing and extent of glaciation throughout Tibet and the bordering mountains, we use geomorphic mapping and 10

The present study includes a review of the geographic and stratigraphic distribution of short-faced bears (Ursidae, Tremarctinae) in South America. In addition, the authors discuss biogeographic hypotheses regarding the origin of South American tremarctines. The Tremarctinae subfamily is distributed exclusively in America, from Alaska to southern Patagonia. Its biochron comprises the temporal lapse between Late Miocene and recent times; the first record of Tremarctinae in North America corresponds to the Hemphillian and the last to the Rancholabrean. In South America, the first record corresponds to the Ensenadan. In the present day, it corresponds to the only living tremarctine, the 'Andean Bear,' but short-faced bears became extinct during the early Holocene. The extinction of short-faced bears in North and South America appears to have been approximately synchronous. Finally, the fossil record in South America indicates species turnover between the Ensenadan and Bonaerian, during which time the giant species Arctotherium angustidens was replaced by Arctotherium tarijense, Arctotherium bonaeriense, and Arctotherium vetustum (and probably Arctotherium wingei). q

The chemical and isotopic characterization of formation water from 18 oil production wells, extracted from 5200 to 6100 m b.s.l. at the Jujo-Tecominoacán carbonate reservoir in SE-Mexico, and interpretations of historical production records, were undertaken to determine the origin and hydraulic behavior of deep groundwater systems. The infiltration of surface water during Late Pleistocene to Early Holocene time is suggested by 14 C-concentrations from 2.15 to 31.86 pmC, and by 87 Sr/ 86 Sr-ratios for high-salinity formation water (0.70923-0.70927) that are close to the composition of Holocene to modern seawater. Prior to infiltration, the super-evaporation of seawater reached maximum TDS concentrations of 385 g/ L, with lowest d 18 O values characterizing the most hypersaline samples. Minor deviations of formation water and dolomite host rocks from modern and Jurassic 87 Sr/ 86 Sr-seawater composition, respectively, suggest ongoing water-rock interaction, and partial isotopic equilibration between both phases. The abundance of 14 C in all sampled formation water, 87 Sr/ 86 Sr-ratios for high-salinity water close to Holocene -present seawater composition, a water salinity distribution that is independent of historic water-cut, and a total water extraction volume of 2.037 MMm 3 (1/83-4/07) excludes a connate, oil-leg origin for the produced water of the Jurassic-Cretaceous mudstone-dolomite sequence. Temporal fluctuations of water chemistry in production intervals, the accelerated migration of water fronts from the reservoir flanks, and isotopic mixing trends between sampled wells confirms the existence of free aquifer water below oil horizons. Vertical and lateral hydraulic mobility has probably been accelerated by petroleum extraction.

We present a synthesis of the palaeolimnological and palaeoclimatic reconstructions of four sites in Colombia. The record from Lake El Caimito, the westernmost site on the Pacific Coast, dates from the Late Holocene and shows lacustrine sedimentation frequently interrupted by fluvial pulses. These pulses probably reflect periods of increased precipitation related to La Niña phases. East of El Caimito site is the Patía swamp, situated between the Western and Central Andean Cordilleras. The Patía records the dynamics of forest expansion/reduction and changes in water levels. Although the climatic signal of the Patia core is difficult to reconstruct, there is a clear increase in humidity in the Mid-Holocene. The Fú quene Lake record, on the Eastern Andean Cordillera, records dry and cold conditions during the Late Pleistocene, very humid conditions for the early Mid-Holocene, and dry conditions during the mid-Late Holocene. Las Margaritas site, on the eastern savannas, records dry conditions during the Early Holocene and overall humid conditions for the Mid-and Late Holocene. Climate conditions from the Fuquene and Las Margaritas sites seem to reflect the Holocene movements of the Intertropical Convergence Zone (ITCZ); the latter site being more affected by humidity coming from the Amazon region. D

Celtis sp. (commonly known as "hackberry") fruits were collected from 101 North American sites located in 13 states and one Canadian province between the years of 1979-1994. The biomineralized carbonate endocarp of the hackberry, which is a common botanical fossil found throughout the Quaternary sediments of the Great Plains, was analyzed for its δ 18 O value and plotted against the δ 18 O value of site environmental water to demonstrate the potential of the hackberry as a paleoclimate indicator. This correlation was reinforced by intensive studies on extracted tissue-water δ 18 O value and hackberry endocarp carbonate δ 18 O value from three trees in Sterling, Colorado. The observed correlation in the large data set between hackberry endocarp carbonate δ 18 O value and environmental water is [endocarp δ 18 O = 38.56 + 0.69 × environmental water δ 18 O] (R = 0.88; R 2 = 0.78; p value < 0.0001). The relation of the hackberry carbonate to temperature in the Great Plains was the following: (average daily-maximum growing season temperature [ • C]) = 6.33 + 0.67 (δ 18 O of endocarp carbonate) (R = 0.73; R 2 = 0.54; p value = 0.0133). The δ 18 O value of early Holocene fossil hackberry carbonate in the Pintwater Cave, southern Nevada, suggested precipitation δ 18 O values more positive than today (∼−4‰ early Holocene vs ∼−9 to −10‰ today). This shift, combined with paleobotanical data, suggests an influx of summer monsoonal moisture to this region in the early Holocene. Alternatively, the more positive δ 18 O values could be viewed as suggestive of warmer temperatures, although the direct use of Great Plains hackberry/ temperature relationships to the Great Basin is of debatable value. C 2001 University of Washington.

Glacial landforms and sediments mapped in three presently unglaciated mountain massifs, the Nanhuta Shan, the Hsueh Shan and the Yushan, support the concept of repeated, multi-stage glaciations in the Taiwanese high mountain range during the late Pleistocene. New results from surface exposure dating using in situ produced cosmogenic 10 Be measured in samples taken from erratic and moraine boulders in Nanhuta Shan at altitudes between 3100 and 3500 m are presented here. The results confirm independent and previously reported Optically Stimulated Luminescence (OSL) ages and 10 Be exposure ages from glacial deposits in the same area and suggest a Lateglacial and early Holocene glaciation, the so called Nanhuta glacier advance with two substages at about 12e15 ka and 9.5 ka BP. The respective equilibrium line altitudes (ELA) were calculated at 3340 m and 3440 m with corresponding ELA depressions of 610 AE 100 m and 510 AE 100 m relative to the present day (theoretical) ELA, which is estimated to be at about 3950 AE 100 m in Taiwan. Large-scale erosional landforms indicate a much wider glacier extent during an earlier stage, which is not dated in Nanhuta Shan so far. Luminescence dating from near Hsueh Shan suggests an age of marine isotope stage (MIS) 4 for this stage.

A multi-proxy approach study (cladocerans, diatoms, geochemistry, plant macrofossils, pollen), was performed on a sediment core from Lake Vrana (Vransko Jezero), a large and deep karstic lake on the northern Adriatic island of Cres, Croatia. Considerable lake-level changes occurred during the last approx. 16,000 years. The stratigraphic evidence suggests that periods of enhanced pre- cipitation and the post-LGM rise in

We present a continuous record of the Asian monsoon over the last 16 ka from y 18 O measurements of stalagmite calcite. Over 900 oxygen isotopic measurements providing information on shifts in monsoon precipitation are combined with a chronology from 45 precise 230 Th dates. y 18 O and therefore Asian monsoon intensity generally follows changes in insolation, although changes in y 18 O are generally accommodated in abrupt shifts in contrast to smoothly varying insolation, indicating that threshold effects may be important. y 18 O decreased dramatically (~3x) at the start of the Holocene (~11.5 ka) and remained low for~6 ka. Four positive y 18 O events centered at 11225F97 yr BP (1.05x), 10880F117 yr BP (1.15x), 9165F75 yr BP (1.4x), and a double event centered at 8260F64 yr BP (1.1x) and 8080F74 yr BP (1.0x) punctuated this period of high monsoon intensity. All four events correlate within error with climate changes in Greenland ice cores. Thus, the relationship between the Asian monsoon and the North Atlantic observed during the glacial period appears to continue into the early Holocene. In addition, three of the four events correlate within error with outburst events from Lake Agassiz. The decline of monsoon intensity in the mid-late Holocene is characterized by an abrupt positive shift in y 18 O which occurs at 3550F59 yr BP (1.1x in~100 yr). In addition, the Holocene is punctuated by numerous centennial-and multi-decadal-scale events (amplitudes 0.5 to 1x) up to half the amplitude of the glacial interstadial events seen in the last glacial period. Thus, Holocene centennialand multi-decadal-scale monsoon variability is significant, although not as large as glacial millennial-scale variability. The monsoon shows a strong connection with northern South American hydrological changes related by changes in ITCZ position. Spectral analysis of the y 18 O record shows significant peaks at solar periodicities of 208 yr and 86 yr suggesting variation is influenced by solar forcing. However, there are numerous other significant peaks including peaks at El Niño frequencies (observed for high-resolution portions of the record between 8110 and 8250 yr) which suggest that changes in oceanic and atmospheric circulation patterns in addition to those forced by solar changes are important in controlling Holocene monsoon Earth and Planetary Science Letters 233 www.elsevier.com/locate/epsl climate. In addition, for this high-resolution portion, we observe a distinctive biennial oscillation of the Asian monsoon, which has been associated with the Tropospheric Biennial Oscillation (TBO).

A catastrophic flooding of the Black Sea basin was proposed to have occurred during its reconnection to the ocean in the early Holocene. Possible cultural consequences of the flood include the migration of Neolithic farmers from around the Black Sea towards central Europe as well as the creation of flood myths. Stratigraphic and paleo-geomorphologic information from Danube delta aided by radiocarbon ages on articulated mollusks constrain the level in the Black Sea before the marine reconnection to ca 30 m below the present sea level rather than 80 m or lower. If the flood occurred at all, the sea level increase and the flooded area during the reconnection were significantly smaller than previously proposed.

Two sediment cores from inner Loch Etive, a deep fjord basin on the west coast of Scotland, reveal a continuous sediment sequence spanning the last 10,000 yr. Benthic foraminiferal assemblages indicate that marine conditions prevailed in Loch Etive throughout the Holocene. However, changes in sediment grain size composition and magnetic susceptibility suggest that the strength and frequency of deep water

A multidisciplinary study has been carried out on a 51 m long core, drilled on coastal lowlands near the Albegna River (Tuscany, Central Italy). Both sedimentological and faunal analyses (ostracods and molluscs) indicate a coastal lagoon environment repeatedly influenced both by the rising Holocene sea and the Albegna River alluvial inflow. δ13C, δ18O, Mg/Ca, Sr/Ca and 87Sr/86Sr analyses were performed on Cyprideis torosa shells in order to detail the influence of Albegna River freshwater on the coastal lagoon water. The analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings. Four radiocarbon dates provide a chronostratigraphy for the early Holocene part of the core. The data are used to reconstruct Late Pleistocene to early Holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial Holocene rapid rise in relative sea level. An attempt is made to relate sediments and age data from the core to the relative sea-level curve for the Tyrrhenian Sea.

Nabta Playa basin offers an unprecedented longitudinal view on the emergence, consolidation and complexification on human-livestock relationships, from the early stage of the Early Holocene (c. 11,000 cal. B.P.) to 6000 B.P. The problem of cattle domestication in Northeastern Africa is considered and hopefully ''solved'' in the light of new mtDNA evidence which suggest an early late Pleistocene split between African, Asian, and Eurasian wild Bos populations. The paper presents a contextualized analysis of almost all the components of archaeological investigation, including climatic change, culture history of Early to Mid-Holocene Nabta-Playans, the development of social differentiation, and probably ranking with ''labor-consuming'' megalithic features with the emergence of characteristic features of pastoral ideology and religions. As far as the emergence and adoption of new foodways are concerned, the cultural development outlined with the Nabta Playa archaeological record is important for the understanding of the Holocene prehistory of Africa as a whole.

Fieldwork conducted at the Nall North locale and the adjacent playa documents buried Paleoindian deposits and a stratigraphic sequence dating back to the late Pleistocene. Cultural debris recovered from the surface of Nall North includes bone, tools, and lithic flake debris. Two buried paleosols at the locale date to the early Holocene and hold high potential for Paleoindian materials. The Baker paleosol, a stabilized surface above the shoreline of the adjacent playa lake, dated between ca. 6870 and 7740 yr B.P., contains a rich cultural component of tools, flakes, and bone, and represents a potential surface for Angostura and Allen/Frederick artifacts. Located below the Baker soil is the Nall soil (dated to ca. 9650 yr B.P.) that probably represents a marsh facies of the playa fill. The Nall soil represents a potential surface for Plainview/Goshen-age artifacts, although excavations thus far have recovered no cultural debris. In the playa adjacent to the Nall North locality, a sequence dating between ca. 12,960 and 5310 yr B.P. documents localized spring flow into the playa during the late Pleistocene, followed by several thousand years of playa muds during the early Holocene, and the eventual drying of the playa in the middle Holocene. © 2003 Wiley Periodicals, Inc.

Archaeologists conductbzg research on the Pleistocene and early Holocene prehistory of Southwest Asia have made a formidable series of new discoveries and fresh insights since 1987. This article examines recent progress and shortcomings on a series of diachronic research topics, including the transition to modern humans, the development of late Pleistocene regionalism and territoriality, the advent of sedentism near the end of the Pleistocene, the origins of food production, and the initial ascendance of social complexity.

This article reassesses the timing, context, and impetus for the onset of sedentary, complex hunter-gatherers, food production, and village life in the Near East during the Late Pleistocene and Early Holocene. Drawing on recent paleoclimatic and archaeological results, I argue that sedentism and then village life were rapid rather than gradual events that occurred during optimal climatic conditions and took place in resource-rich settings. These two social milestones included fundamental changes in economic strategies, social interaction, and ideology. Only by understanding the interplay between preexisting social institutions and human agency within communities prior to and during these periods of major social change will we be able to understand how and why food production began.

The Venetian-Friulian Plain is the eastern part of the foreland basin of the Southern Alps and is characterized by the presence of alluvial megafans. Existence of these large landforms results from the tectonic setting, but their Late Pleistocene and Holocene evolution has been mainly controlled by climatic change and eustasy. Geomorphological, geological information and radiocarbon dating allow the recognition of phases of sedimentation and incision in the megafans of the Brenta, Piave and Tagliamento rivers. The main phase of aggradation took place during the Last Glacial Maximum (LGM) (24-15 ka BP), when the glaciers emanating from the Alpine valleys reached the plain and supplied large amounts of sediments. During the Late LGM the rate of aggradation lowered in the Brenta megafan and a wide incision of the fanhead developed in the Tagliamento megafan. During Late Glacial and Early Holocene an important phase of incision took place, and smaller telescopic lobes formed in the distal portion of Brenta and Tagliamento megafans. Sedimentation was absent or very low between 14 and 8 ka BP and only since the Middle Holocene a new phase of deposition affected the coastal areas, probably related to a marine highstand. Widespread aggradation started once more around 4-3 ka BP, with the formation of fluvial ridges along the terminal tract of Alpine rivers. Since the Roman period, human influence affected the alluvial sedimentation, especially in the last centuries, due to land reclamation and construction of river embankment. r

As the planet cooled from peak warmth in the early Cenozoic, extensive Northern Hemisphere ice sheets developed by 2.6 Ma ago, leading to changes in the circulation of both the atmosphere and oceans. From w2.6 to w1.0 Ma ago, ice sheets came and went about every 41 ka, in pace with cycles in the tilt of Earth's axis, but for the past 700 ka, glacial cycles have been longer, lasting w100 ka, separated by brief, warm interglaciations, when sea level and ice volumes were close to present. The cause of the shift from 41 ka to 100 ka glacial cycles is still debated. During the penultimate interglaciation, w130 to w120 ka ago, solar energy in summer in the Arctic was greater than at any time subsequently. As a consequence, Arctic summers were w5 C warmer than at present, and almost all glaciers melted completely except for the Greenland Ice Sheet, and even it was reduced in size substantially from its present extent. With the loss of land ice, sea level was about 5 m higher than present, with the extra melt coming from both Greenland and Antarctica as well as small glaciers. The Last Glacial Maximum (LGM) peaked w21 ka ago, when mean annual temperatures over parts of the Arctic were as much as 20 C lower than at present. Ice recession was well underway 16 ka ago, and most of the Northern Hemisphere ice sheets had melted by 6 ka ago. Solar energy reached a summer maximum (9% higher than at present) w11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1e3 C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers reestablished or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean Quaternary Science Reviews 29 diminished. Late Holocene cooling reached its nadir during the Little Ice Age (about 1250e1850 AD), when sun-blocking volcanic eruptions and perhaps other causes added to the orbital cooling, allowing most Arctic glaciers to reach their maximum Holocene extent. During the warming of the past century, glaciers have receded throughout the Arctic, terrestrial ecosystems have advanced northward, and perennial Arctic Ocean sea ice has diminished.

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Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145 AE 20 kyr, 83 AE 24 kyr, 32 AE 8 kyr and 20.7 AE 0.2 kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8 AE 3.2 kyr, with still high but somewhat reduced flow in that river at 13.3 kyr, 10 kyr and 4.8e4.0 kyr. Beach ridges associated with a 386 m strandline of the White Nile have OSL ages of 27.5 AE 2.7 kyr and 14.5 AE 1.6 kyr. The Holocene terraces and former channels of the main Nile have ages of 11 kyr, 6.5e5.0 kyr and 4.8e4.0 kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450 km 2 in area, fed by an overflow channel from the early Holocene Nile between 9.5 kyr and 7.5 kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9 AE 2.0 kyr, 9.0 AE 2.8 kyr, 6.6 AE 0.9 kyr, 4.8 AE 0.9 kyr and 2.9 AE 0.5 kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0 kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region.

Archaeologists working in northeastern North America continue to rely heavily on stone tool technology and the sourcing of raw materials for their interpretations of mobility and territoriality among Paleoindians during the late Pleistocene and early Holocene. Hunter gatherer band ranges refl ected in the lithic raw material use on Early Paleoindian sites are presented for the region of eastern New York, southeastern Quebec and New England. While there has been a greater focus on the accurate geological sourcing of stone tool raw materials using petrography and chemical characterization within the last fifteen years, substantial basic research remains to be done. These studies, combined with a greater attention to the organization of stone tool technology (e.g., chaîne opératoire), should permit archaeologists to revisit and in some cases reinterpret the question of Paleoindian mobility and territoriality.

Decades ago the Diablo Canyon site (CA-SLO-2) on the central California mainland revealed one of the oldest and longest sequences (ca. 9400 radiocarbon years ago to contact) of coastal occupation on the shore of the northeastern Pacific. The artifacts from these important deposits were reported in detail by , but only a fraction of the site's faunal collections was analyzed in the original site report. Acquisition of 30 additional radiocarbon dates and analysis of the complete vertebrate fauna have produced a coarse-grained record of human foraging on the California mainland from 8300 cal B.C. to cal A.D. 1769. The temporally controlled faunal matrix, constituting one of the largest trans-Holocene records from western North America, speaks in a meaningful way to two significant issues in hunter-gatherer prehistory: early Holocene foraging strategies and economic intensification/resource depression over time. The site's earliest component suggests a population invested in watercraft and intensely adapted to the interface of land and sea along the northeastern Pacific coastline. While boats were used to access offshore rocks, terrestrial mammals (e.g., black-tailed deer) were also of primary importance. Dominance of deer throughout the Diablo occupations is inconsistent with recent generalizations about big-game hunting as costly signaling in western North American prehistory. Diachronic variation, correlated with superimposed burials that show growth in human populations through the Holocene, includes: (1) modest incremental changes in most taxa, suggesting resource stability and increasing diet breadth; (2) gradual but significant variation in a few taxa, including the flightless duck which was hunted into extinction and eventually replaced by sea otters; (3) punctuated, multidirectional change during the late Holocene related to historic contingencies of the Medieval Climatic Anomaly and protohistoric disruptions.

The fluvial systems and landscape of the drylands of western India have preserved evidence of Late Quaternary environmental and tectonic changes. Data on the fluvial systems of Mainland Gujarat, Saurashtra and Kachchh have been synthesised to evaluate the roles of geological factors in the evolution of these drylands. Mainland Gujarat is largely underlain by the flat alluvial plain, and has a structurally controlled fluvial system that originates in the eastern uplands. The fluvial system of Mainland Gujarat shows deeply incised valleys, entrenched meanders, extensively developed ravines and uplifted terraces, which have preserved a Late Quaternary succession of continental (fluvial and aeolian) and marine sediments dating back to B125 ka: Marine sediments correspond to the transgressive phases of the last interglacial ðB125 kaÞ and post-glacial maximum ð6 kaÞ: The overlying alluvial sediments suggest deposition by ephemeral rivers in varied fluvial depositional environments under a semi-arid to sub-humid climatic regime with periods of intense pedogenesis. The sedimentation can be correlated with marine isotopic stages (MIS) 5 and 3. The fluvial sediments are buried under a thick blanket of aeolian sediments, which are indicative of enhanced dune building activity in the Thar Desert and are correlatable to the global arid phase of the last glacial maximum. The post-aeolian tectonic uplift triggered severe erosion of Late Pleistocene sediments and 40-50 m deep incised fluvial valleys were formed. This erosional phase suggests a resumption of fluvial activity, which coincided with the rapidly rising sea level on the west coast during the Early Holocene. The Holocene marine and fluvial aggradation was initiated within the incised fluvial valleys around 6 ka and continued uninterrupted until B2 ka: These sediments now occur as raised valley fill terraces suggesting a Late Holocene uplift further corroborated by low to moderate seismic activity during historical times. The landscape of Saurashtra is marked by flat-topped basaltic (trappean) ridges and a highly varied coastline where a narrow belt of low ridges and cliffs of miliolite limestones and other shore deposits are found. The fluvial system of Saurashtra shows a radial drainage pattern. The channels have steep banks in the hilly regions and show significant deflections before meeting the sea. Evidence of last interglacial high sea levels ðB125 kaÞ are found on the coastal cliffs of southern Saurashtra in the form of oyster reefs and notches of various types which now occur at higher levels. A net sea level rise of þ7 m consistent with the global sea level estimates at 125 ka has been obtained by recent studies after decoupling the tectonic component. Dating of Late Pleistocene and Holocene sea levels on this coast suggest continued uplift of Saurashtra since 125 ka even though the sea level continued to fluctuate. The Holocene high sea submerged a considerable stretch of land including the Okha Rann on the northern Saurashtra coast and isolated patches in and around the river mouths on the southern coast. The short, straight and parallel courses of rivers in the direction of tectonic slope, incised and confined channel belts also suggest a strong component of tectonic uplift. The continental sediments exposed in these river valleys have however remained uninvestigated leading to lack of palaeoclimatic data. A remarkable control of structure on landscape evolution is depicted by the Kachchh peninsula. The fluvial system exhibits the characteristics of drainage flowing along tectonically provided slopes. The overall drainage pattern of Kachchh shows excellent correlation with N-S trending transverse fault patterns. The transverse fault system has brought out changes in the landscape of Kachchh though the Kachchh rift basin evolved along E-W latitudinal faults. The Quaternary deposits occur in the form of miliolite limestones, colluvial and alluvial fans, fluvial sands and silts, and Rann sediments. Significant sedimentologic details on these sediments are lacking. However, the marine incursions seem to correlate with the adjacent Saurashtra and Mainland Gujarat.

Geomorphic data combined with stratigraphic studies provide significant information to constrain timing and amount of fault movement. The lower Narmada valley lies astride the Narmada -Son Fault (NSF), an important ENE -WSW-trending tectonic element responsible for the current intraplate seismicity being experienced in the central part of the Indian plate. Varying nature and degree of tectonic movements along the NSF during Late Pleistocene and Holocene have produced four geomorphic surfaces in the lower Narmada valley: the alluvial plain (S 1 ), ravine surface (S 2 ), a gravelly fan surface (S 3 ) and the valley fill terrace surface (S 4 ). Two major phases of tectonic movements in a compressive stress regime are recorded along the NSF: slow synsedimentary subsidence of the basin during Late Pleistocene due to differential movement, followed by inversion of the basin during the Holocene marked by differential uplift along the NSF. The study suggests that the inversion of the basin is in response to the significant increase in the intensity of compressive stresses in the Indian plate mainly during the Early Holocene. The present incisive drainage and recent seismic activity indicate that the compressive stresses continue to accumulate along the NSF due to continued northward movement of the Indian plate. D

Borehole data from the Ganges-Brahmaputra delta system unveil an intriguing Late Quaternary history controlled by immense sediment discharge, tectonics, and eustasy. Sea level first intersected a major portion of the lowstand surface ϳ10,000-11,000 cal yr BP, marking the onset of sediment trapping and delta growth. Despite rapid sea-level rise (Ͼ1 cm/yr), sediment load was sufficient to maintain relative shoreline stability during this time. By ϳ7000 cal yr BP, accommodation was quickly infilled with slowed sea-level rise, leading to upstream channel migration and widespread dispersal of sands. This forced coastal progradation along the western delta front where the Ganges was situated, and much of the river's fine-grained discharge bypassed the subaerial delta and formed a prograding deltaic clinoform on the shelf. Concurrently, Brahmaputra sediments were sequestered to an inland tectonic basin, thus starving the adjacent shoreline and leading to transgression along the eastern delta. By ϳ5000 cal yr BP, the two rivers had migrated or changed course to discharge along the eastern delta shoreline which began to prograde into what is now the modern river-mouth estuary. Present delta configuration appears to have developed by ϳ3000 cal yr BP. Evolution of the tectonically active Ganges-Brahmaputra (G-B) system reveals important similarities and differences with other deltas. Overall facies succession follows that of basic models, progressing from an alluvial valley to coastal marine delta front to a prograding subaerial delta plain. However, the timing, thickness, and controls of these deposits differ. Immense sediment discharge from the Ganges and Brahmaputra rivers allowed initial delta growth 2000-3000 yr earlier than the global average, despite debouching onto a canyon-incised, high-energy margin. Subsequently, a thick (ϳ50 m) transgressive systems tract was formed during the early Holocene phase of delta aggradation, contrasting with extensive shoreline retreat documented along most margins. Highstand progradation of coastal and shelf sequences ensued by the middle Holocene, but subsiding inland basins also favored accumulation of a thick (to 40 m) highstand sequence in the lower floodplains. Unlike many other delta systems, subsidence in the subaerial G-B delta is not dominated by compaction, but rather by plate-driven tectonic processes that generate rates up to 4 mm/year. Overall, the huge sediment load, tectonic subsidence, major seismic events, and a nearshore canyon system have led to widespread sediment dispersal and sequence formation across the subaerial delta, shelf, and deep-sea Bengal Fan throughout the Late Quaternary. ᭧