Before The Present Research Articles

The Cyrenaican Prehistory Project 2012: the fifth season of investigations of the Haua Fteah cave

AbstractThe paper reports on the fifth (2012) season of fieldwork of the Cyrenaican Prehistory Project. The primary focus of the season was the continuation of the excavation of the prehistoric occupation layers in the Haua Fteah cave. A small trench (Trench U) was cut into Holocene (Neolithic) sediments exposed on the south wall of Charles McBurney's Upper Trench. Below this, the excavation of Trench M was continued, on the southern side of McBurney's Middle Trench. In previous seasons we had excavated Oranian ‘Epipalaeolithic’ layers dating toc.18,000–10,000 BP (years before the present). In 2012 the excavation continued downwards through Dabban ‘Upper Palaeolithic’ occupation layers, one of which was associated with a post-built structure and likely hearths. There are indications of an occupational hiatus separating the oldest Dabban from the youngest Levallois-Mousterian (Middle Palaeolithic or Middle Stone Age) lithic material. The Deep Sounding excavated by Charles McBurney in 1955 was cleared of backfill to its base, and its south-facing wall was recorded in detail and sampled extensively for materials for dating and palaeoenvironmental reconstruction. McBurney believed that he had reached bedrock at the base of the Deep Sounding, but a small sounding (Trench S) cut into the sediments below this level found further, albeit sparse, evidence for human occupation. Whilst the antiquity of ‘Pre-Aurignacian’ human occupation at the site still needs to be resolved, it seems likely to reach back at least to Marine Isotope Stage 5e, the beginning of the last interglacial (c.130,000–115,000 BP). Important finds from the 2012 excavations in terms of the behavioural complexity of the human groups using the cave include a possible worked bone point from a Pre-Aurignacian layer and a granite rubbing stone in a Dabban layer from a source over 600 km from the cave.

Late Pleistocene monsoon variability in northwest Thailand: an oxygen isotope sequence from the bivalve Margaritanopsis laosensis excavated in Mae Hong Son province

Long, continuous records of Late Quaternary environmental change are rare in Southeast Asia, yet they are crucial for understanding the nature of early human dispersal and occupation in the Australasian region. We present a new record of palaeomonsoon activity extending back to 35,000 BP (years before the present), based on the analysis of oxygen isotope ratios (δ 18O) in the freshwater bivalve Margaritanopsis laosensis excavated from the Tham Lod and Ban Rai rockshelters in Mae Hong Son Province, northwest Thailand. Long-term changes in the M. laosensis δ 18O record reflect changes in the δ 18O of the river water in which these organisms grew, and correlate well with changes in speleothem δ 18O records of east Asian monsoon rainfall from Hulu Cave and Dongge Cave in China. The new northwest Thailand δ 18O sequence indicates wetter and relatively unstable climatic conditions from 35,000 to 20,000 BP, followed by drier conditions from 20,000 to 11,500 BP. A period of peak aridity occurred around 15,600 BP during Heinrich Event 1, suggesting that the intertropical convergence zone shifted southward when the North Atlantic region cooled. However, there is little evidence for the Younger Dryas event at ∼12,800–11,500 BP. After 9,800 BP, precipitation increased substantially and climatic variability declined. Our findings provide an improved baseline against which to gauge interactions between early humans and climate change in Southeast Asia. For example, there was no significant change in the prehistoric flake stone technology used at Tham Lod and Ban Rai despite the bivalve δ 18O evidence for substantial climate change in the region. Also, the climatic impact of the Younger Dryas event appears to have been less intense in northwest Thailand compared to the cooling and drying observed in China, and may explain why agriculture made a relatively late appearance in Thailand, possibly involving migrants from China.

Novelty‐seeking DRD4 polymorphisms are associated with human migration distance out‐of‐Africa after controlling for neutral population gene structure

Numerous lines of evidence suggest that Homo sapiens evolved as a distinct species in Africa by 150,000 years before the present (BP) and began major migrations out-of-Africa ∼50,000 BP. By 20,000 BP, our species had effectively colonized the entire Old World, and by 12,000 BP H. sapiens had a global distribution. We propose that this rapid migration into new habitats selected for individuals with low reactivity to novel stressors. Certain dopamine receptor D4 (DRD4) polymorphisms are associated with low neuronal reactivity and increased exploratory behavior, novelty seeking, and risk taking, collectively considered novelty-seeking trait (NS). One previous report (Chen et al.: Evol Hum Behav 20 (1999) 309-324) demonstrated a correlation between migratory distance and the seven-repeat (7R) VNTR DRD4 allele at exon 3 for human populations. This study, however, failed to account for neutral genetic processes (drift and admixture) that might create such a correlation in the absence of natural selection. Furthermore, additional loci surrounding DRD4 are now recognized to influence NS. Herein we account for neutral genetic structure by modeling the nonindependence of neutral allele frequencies between human populations. We retest the DRD4 exon 3 alleles, and also test two other loci near DRD4 that are associated with NS. We conclude there is an association between migratory distance and DRD4 exon 3 2R and 7R alleles that cannot be accounted for by neutral genetic processes alone.

Reduced North Atlantic Deep Water Coeval with the Glacial Lake Agassiz Freshwater Outburst

An outstanding climate anomaly 8200 years before the present (B.P.) in the North Atlantic is commonly postulated to be the result of weakened overturning circulation triggered by a freshwater outburst. New stable isotopic and sedimentological records from a northwest Atlantic sediment core reveal that the most prominent Holocene anomaly in bottom-water chemistry and flow speed in the deep limb of the Atlantic overturning circulation begins at approximately 8.38 thousand years B.P., coeval with the catastrophic drainage of Lake Agassiz. The influence of Lower North Atlantic Deep Water was strongly reduced at our site for approximately 100 years after the outburst, confirming the ocean's sensitivity to freshwater forcing. The similarities between the timing and duration of the pronounced deep circulation changes and regional climate anomalies support a causal link.

Rapid rise of sea level 19,000 years ago and its global implications.

Evidence from the Irish Sea basin supports the existence of an abrupt rise in sea level (meltwater pulse) at 19,000 years before the present (B.P.). Climate records indicate a large reduction in the strength of North Atlantic Deep Water formation and attendant cooling of the North Atlantic at this time, indicating a source of the meltwater pulse from one or more Northern Hemisphere ice sheets. Warming of the tropical Atlantic and Pacific oceans and the Southern Hemisphere also began at 19,000 years B.P. These responses identify mechanisms responsible for the propagation of deglacial climate signals to the Southern Hemisphere and tropics while maintaining a cold climate in the Northern Hemisphere.

Clovis in context: New light on the peopling of the Americas

Until recently, the first Americans were thought to be fluted-point spear-hunters from the Siberian steppes. Near the end of the Ice Age, they followed big-game herds over the Bering land bridge into the open, upland habitats of the interior of North America about 12,000 years ago. Rapidly extinguishing the big game herds with their deadly hunting methods, they pressed southward in search of new herds and reached the tip of South America about a thousand years later. Today, nearly 70 years after the first excavations at Clovis, New Mexico, the type site for this culture, new sites and new dates from both North and South America are forcing a revision of the earlier picture of the migrations and adaptations of the first Americans. But despite recurring claims that human colonization of the Western Hemisphere began as early as 20,000 or more years ago with the arrival of generalized foragers lacking a projectile-point tradition, no definitive data gives empirical support for a human presence before c. 12,000 before the present (B.P.). All supposed pre-Clovis cultures except one in Alaska have failed to withstand careful scrutiny of their data. In addition, despite recent claims for cultural and biological links of the migrants to Europe or the Pacific Islands, the skeletons and cultural assemblages of Paleoindians throughout the hemisphere point consistently to a northeast Asian origin. According to new data, Paleoindian ancestors in Beringia c. 12,000 years ago were not specialized, fluted-point hunters of large game, but broad-spectrum hunter-gatherers using triangular or bipointed, lanceolates. Diverse cultures descended from these ancestors, not only the big-game hunting Clovis culture of the North American high plains. And just as Clovis did not set the cultural pattern for the hemisphere, it was not the earliest culture. Fully contemporary with the earliest possible Clovis dates of c. 11,200, in South America there already were maritime foragers on the Pacific coast, small-game hunters in the southern pampas, and tropical forest riverine foragers in the eastern tropical lowlands. The Clovis culture thus was just one of several regional cultures developed in the millennium after the initial migration. It could not have been the ancestor of the other early Paleoindian cultures.

Prehistoric sunflower (Helianthus Annuus L.) domestication in Mexico

Early remains of Helianthus annuus L. unearthed at the San Andres site in the Gulf Coast region of Tabasco, Mexico, constitute the earliest record of domesticated sunflower. Accelerator mass spectrometry (AMS) age determinations of a large domesticated seed and achene produced dates of 4130 ± 40 years before the present (B.P.) and 4085 ± 50 B.P., respectively. These discoveries challenge the longstanding hypothesis that sunflower was domesticated in eastern North America. Moreover, when considered with other recent discoveries on plant domestication, these data suggest a reconsideration of the idea that the eastern United States was an independent hearth for domestication.

Direct radiocarbon dates for Vindija G(1) and Velika Pecína late Pleistocene hominid remains.

New accelerator mass spectrometry radiocarbon dates taken directly on human remains from the Late Pleistocene sites of Vindija and Velika Pecina in the Hrvatsko Zagorje of Croatia are presented. Hominid specimens from both sites have played critical roles in the development of current perspectives on modern human evolutionary emergence in Europe. Dates of approximately 28 thousand years (ka) before the present (B.P.) and approximately 29 ka B.P. for two specimens from Vindija G(1) establish them as the most recent dated Neandertals in the Eurasian range of these archaic humans. The human frontal bone from Velika Pecina, generally considered one of the earliest representatives of modern humans in Europe, dated to approximately 5 ka B.P., rendering it no longer pertinent to discussions of modern human origins. Apart from invalidating the only radiometrically based example of temporal overlap between late Neandertal and early modern human fossil remains from within any region of Europe, these dates raise the question of when early modern humans first dispersed into Europe and have implications for the nature and geographic patterning of biological and cultural interactions between these populations and the Neandertals.

A mid-european decadal isotope-climate record from 15,500 to 5000 years B.P

Oxygen-isotope ratios of precipitation (delta18OP) inferred from deep-lake ostracods from the Ammersee (southern Germany) provide a climate record with decadal resolution. The record in detail shows many of the rapid climate shifts seen in central Greenland ice cores between 15,000 and 5000 years before the present (B.P.). Negative excursions in the estimated delta18OP from both of these records likely reflect short weakenings of the thermohaline circulation caused by episodic discharges of continental freshwater into the North Atlantic. Deviating millennial-scale trends, however, indicate that climate gradients between Europe and Greenland changed systematically, reflecting a gradual rearrangement of North Atlantic circulation during deglaciation.

Plio-Pleistocene Hyracoidea from Swartkrans Cave, South Africa

Swartkrans Cave, an important Pleistocene hominid site in the Sterkfontein valley, has yielded abundant (ossil hyracoid remains. Two extinct taxa, Procavia antiqua and P. transvaalensis, have been previously reported to occur at the site in deposits postdating 1,8 million years before the present (B.P.). The extant taxon, P. capensis, has been reported in the most recent deposits, thought to include the Terminal Pleistocene. However, statistical analyses of teeth suggest that P. antiqua and P. capensis are conspecific. P. transvaalensis differs from P. capensis by being larger and more hypsodont. The coexistence of these taxa in palaeoenvironments of the Sterkfontein valley is attributed to dietary differences: P. transvaalensis being dependent primarily on grass foliage in grassland habitats, P. capensis being a generalist, feeding on a range of different kinds of vegetation in rocky habitats. Hypoconid-metaconid distances, previously used by Broom to distinguish taxa, are shown to be related to individu...

High energy ultraviolet photo‐oxidation: a novel technique for studying physically protected organic matter in clay‐ and silt‐sized aggregates

SUMMARYA novel approach to the study of organic‐matter distribution in soil microaggregates (<20 μm) using high‐energy ultraviolet (UV) radiation in the presence of oxygen (photo‐oxidation) is reported. The method quantitatively destroyed complex organic materials through oxidation, even in the presence of clay, provided the organic materials were directly exposed to the UV radiation.Photo‐oxidation of clay and silt fractions for periods up to 8 h demonstrated that a considerable proportion of the organic matter was physically protected within clay‐ and silt‐sized aggregates. In some clay fractions, up to 23% of the organic carbon could be considered as physically protected whereas in silt fractions this was as high as 36%.Infrared spectroscopy demonstrated that the materials external to both clay‐ and silt‐sized aggregates were largely proteinaecous in nature, while the materials in the interior of the aggregates resembled humic acids. These humic materials appeared to be physically shielded against photo‐oxidation, rather than being chemically recalcitrant. Using the clay‐ and silt‐sized fractions from one soil, 14C accelerator mass spectrometry demonstrated that, although both clay and silt fractions contained essentially modern carbon, after 4 h of photo‐oxidation much older organic carbon with a mean resonance time (MRT) of between 200±80 and 320±80 years before the present (BP) remained. This protection from photo‐oxidation, therefore, appears to mirror the process which physically protects organic substances in soils against microbial degradation. Photo‐oxidation of the clay‐plus‐silt fractions also resulted in a considerable reduction in particle size as the organic‐cementing agents, consisting of proteinaecous and humic materials, were oxidized.Using data from the photo‐oxidation method along with infrared spectroscopy, radiocarbon dating and scanning electron microscopy, a simple model is proposed that spatially relates the various organic structures present to their positions in the mineral aggregates.

From Hunting and Gathering to Agriculture

The purpose of this article is to provide a simple economic general equilibrium model of one of the most important prehistoric eventsthe transition from hunting and gathering to agriculture. It is hoped that such a model will help focus the discussion about this important occurrence and that it will aid in identifying the implications of the many hypotheses that have been put forth to explain why, when, and where the transition to agriculture took place. Viewed in the proper time frame, the transition to agriculture was dramatic in terms of the large number of people and the relatively short time period involved, as well as the enormous accompanying changes in the way people lived their lives. For about 4 million years man lived by harvesting wild foods. Slightly more than 10,000 years B.P. (before the present) the transition to agriculture began, and by 2,000 years B.P. the vast majority of people depended on agriculture as their main form of subsistence.' Of course, it was not only subsistence pursuits that changed. For example, estimates of population growth rates for the early agricultural period (Neolithic) are around 100 times greater than those for the hunting-gathering period.2 Estimates of population density are correspondingly higher for the agricultural period. It has been claimed that the transition in France was accompanied by a hundredfold increase in population, as opposed to a tenfold increase between the period of early farming and the present.3 The early theories of the transition, dating back to the Greeks, viewed the human economy as developing in a series of stages, with agriculture being the last stage.4 These were later modified by the introduction of environmental differences to explain why in some regions development stopped short of the last stage, or why development took place at different rates across regions. This approach fell into disfavor when the traditional sequence of stages (hunting-gathering, pastoral nomadism, agriculture) was shown to be incorrect. Rather than altering the sequence of stages, a different approach became

Development of a Tidal Marsh in a New England River Valley

A model for the geomorphic and vegetation development of a river valley tidal marsh in southern New England (Connecticut) is based on both the species composition of roots and rhizomes and on the mineralogic sediments preserved in peat. The maximum depth of salt marsh peat is 3.8 m and in the deepest areas this can overlie up to 1.9 m of fresh to brackish water peat. Based on a radiocarbon date of 3670±140 yr before the present (B.P.) for basal peat at a depth of 4.0 m, vertical accretion rates have averaged ca. 1.1 mm yr−1. Salt marsh formation began in response to rising sea level 3800–4000 yr B.P., as brackish marshes, dominated by bulrush (Scirpus sp.), replaced freshwater wetlands along stream and river channels. Gradually salt marsh vegetation developed over submerging brackish marshes, adjacent uplands, and accreting tidal flats. By 3000 yr B.P. the lower estuary was tidal, with sufficient salinity for salt marsh to dominate most wetlands. Spikegrass (Distichlis spicata) was an important early colonizer in salt marsh formation and its role in marsh development has not been documented previously. Blackgrass (Juncus gerardi), currently a typical upper border species, appears in the peat record relatively recently, perhaps within the last few centuries. In contrast, reed (Phragmites australis) has been present for at least 3500 yr. The dominance of reed along the upper border today, however, appears to be a relatively recent phenomenon.

Carbon-14 Dates at Grande Pile: Correlation of Land and Sea Chronologies

Sixteen radiocarbon dates extending back to 70,000 years provide a chronology for the continuous continental pollen record of Grande Pile. This record reflects climatic changes over the last 140,000 years in northeastern France. The cold period initiating the Middle Weichselian, dated previously at 55,000 years, is dated at 70,000 years before the present (B.P.) at Grande Pile. This event is marked by the disappearance of deciduous forests at this site. The Early Weichselian is placed before 70,000 years B.P. A correlation with the oxygen isotope stages from oceanic records is demonstrated until 70,000 years B.P. and attempted beyond.

Early Deglaciation of the Labrador Shelf

Two marine sediment cores from a basin on the southeastern Labrador Shelf penetrate a mud sequence extending back to 21,000 carbon-14 years before the present (B.P.). The benthic foraminifera are dominated by subartic nearshore species indicative of ice-free summer waters. The pollen record indicates the presence of a sedge-shrub tundra in eastern Labrador as early as 21,000 years B.P. Both sources of evidence suggest less extensive continental ice than has previously been reported for this subarctic region.

North Atlantic Ice-Rafting: A Major Change at 75,000 Years Before the Present

During the last interglacial-to-glacial climatic cycle [127,000 to 10,000 years before the present (B.P.)], the fundamental geographic shift in the main axis of ice-rafting deposition occurred at 75,000 years B.P. An earlier meridional depositional maximum along the Greenland-Newfoundland coasts was superseded by a nearly zonal and much stronger axis some 1500 kilometers to the south along 40 degrees N to 50 degrees N. Both depositional patterns are best explained by cyclonic flow in the subpolor gyre, with the depositional shift related to the retreat of warm, ice-melting North Atlantic drift water from the northwestern half of the gyre. Similar shifts must have characterized preceding interglacial-glacial cycles.

Late-Quaternary Climatic Trends and History of Lake Erie from Stable Isotope Studies

Oxygen and carbon isotope measurements on mollusk and carbonate shells separated from a long sediment core in central Lake Erie document climatic changes of the Great Lakes region and the evolution of Lake Erie since deglaciation. On the basis of 18 O data, two major climatic improvements are recognized, one occurring between 13,000 and 12,000 years before the present (B.P.) and the other between 10,000 and 8,000 years B.P. Changing drainage patterns are also reflected in the 18 O contents of the Lake Erie water. Carbon isotopes reflect changes in aquatic vegetation and water depth. The settlement and industrialization of the Lake Erie drainage basin is documented in the 13 C and 18 O contents of modern mollusks.

Age Determination of Burned Flint by a Thermoluminescent Method

Interference by tribothermoluminescence and by regeneration thermoluminescence can be eliminated for burned flint if thin polished slices are used instead of the powders conventionally used in thermoluminescent measurements. Measurement of the internal and external radiation dose rates then makes possible the absolute determination of the date of pyrolization of small fragments of chert or chalcedony to an accuracy of about 10 to 15 percent. The method may be usable to ages in the range from 200,000 to 300,000 years before the present (B.P.). For samples from the archeological site at Carigüela in southern Spain dates from 12,000 to 50,000 years B.P. have been determined, covering deposits ranging from Late Paleolithic-Epipaleolithic to Mousterian. One Bronze Age specimen gave an age of 4,300 years B.P., in excellent agreement with the age determined by other methods.

Arlington Springs man.

Bones of a man were found at a depth of 37 feet in waterlaid sediments on Santa Rosa Island, California, and dated by radiocarbon at 10,000 years before the present (B.P.). Two later occupational levels are dated at 7350 and 2090 years B.P. No artifacts are associated with the oldest bones, which are believed to be an accidental burial on the edge of a cienaga.

Geochronology of the Deglacial and Neothermal Ages

This is a review of the chronologies based on varved (annually laminated) sediments and a revision of the estimates of the gaps in the varve data. A Finno-Swedish chronology by Gerard De Geer, Ragner Liden, and Matti Sauramo covers the last 11,600 years. It is based on 650 historical years (A.D. 1300-1950), 380 interpolated years (A.D. 920-1300), and the rest on postglacial and glacial varves. The Salpausselka or Younger Dryas age is dated at 10810-10150 B.P. (before the present, 1950). The marked temperature rise which caused the departure of the ice from Salpausselka II in the Finnish year + 1 or 10150 B.P. is taken as the beginning of the Neothermal (European Postglacial) age. The North American chronology ends during the ice oscillations at Cochrane, south of James Bay. These are correlated with the comparably located Nyland and Salpausselka halts in southern Finland. Thus the drainage of Lake Ojibway and varve Timiskaming no. 2025 are dated at about 11300 B.P., and the Cochrane oscillations at 11300-...