Human occupations and climate change in the Puna de Atacama,Chile

Widespread evidence for human occupation of the Atacama Desert, 20 degrees to 25 degrees S in northern Chile, has been found from 13,000 calibrated 14C years before the present (cal yr B.P.) to 9500 cal yr B.P., and again after 4500 cal yr B.P. Initial human occupation coincided with a change from very dry environments to humid environments. More than 39 open early Archaic campsites at elevations above 3600 meters show that hunters lived around late glacial/early Holocene paleolakes on the Altiplano. Cessation of the use of the sites between 9500 and 4500 cal yr B.P. is associated with drying of the lakes. The mid-Holocene collapse of human occupation is also recorded in cave deposits. One cave contained Pleistocene fauna associated with human artifacts. Faunal diversity was highest during the humid early Holocene.     

Origins of agriculture at Kuk Swamp in the highlands of New Guinea

Multidisciplinary investigations at Kuk Swamp in the Highlands of Papua New Guinea show that agriculture arose independently in New Guinea by at least 6950 to 6440 calibrated years before the present (cal yr B.P.). Plant exploitation and some cultivation occurred on the wetland margin at 10,220 to 9910 cal yr B.P. (phase 1), mounding cultivation began by 6950 to 6440 cal yr B.P. (phase 2), and ditched cultivation began by 4350 to 3980 cal yr B.P. (phase 3). Clearance of lower montane rainforests began in the early Holocene, with modification to grassland at 6950 to 6440 cal yr B.P. Taro (Colocasia esculenta) was utilized in the early Holocene, and bananas (Musa spp.) were intensively cultivated by at least 6950 to 6440 cal yr B.P.     

The history of South American tropical precipitation for the past 25,000 years

Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much of the Amazon basin were wetter than today. The LGM in this part of the Andes is dated at 21,000 cal yr B.P., approximately coincident with the global LGM. Maximum aridity and lowest lake level occurred in the early and middle Holocene (8000 to 5500 cal yr B.P.) during a time of low summer insolation. Today, rising levels of Lake Titicaca and wet conditions in Amazonia are correlated with anomalously cold sea-surface temperatures in the northern equatorial Atlantic. Likewise, during the deglacial and Holocene periods, there were several millennial-scale wet phases on the Altiplano and in Amazonia that coincided with anomalously cold periods in the equatorial and high-latitude North Atlantic, such as the Younger Dryas.     

Climate-driven ecosystem succession in the Sahara: the past 6000 years

Desiccation of the Sahara since the middle Holocene has eradicated all but a few natural archives recording its transition from a "green Sahara" to the present hyperarid desert. Our continuous 6000-year paleoenvironmental reconstruction from northern Chad shows progressive drying of the regional terrestrial ecosystem in response to weakening insolation forcing of the African monsoon and abrupt hydrological change in the local aquatic ecosystem controlled by site-specific thresholds. Strong reductions in tropical trees and then Sahelian grassland cover allowed large-scale dust mobilization from 4300 calendar years before the present (cal yr B.P.). Today's desert ecosystem and regional wind regime were established around 2700 cal yr B.P. This gradual rather than abrupt termination of the African Humid Period in the eastern Sahara suggests a relatively weak biogeophysical feedback on climate.     

Climate-controlled Holocene occupation in the Sahara: motor of Africa's evolution

Radiocarbon data from 150 archaeological excavations in the now hyper-arid Eastern Sahara of Egypt, Sudan, Libya, and Chad reveal close links between climatic variations and prehistoric occupation during the past 12,000 years. Synoptic multiple-indicator views for major time slices demonstrate the transition from initial settlement after the sudden onset of humid conditions at 8500 B.C.E. to the exodus resulting from gradual desiccation since 5300 B.C.E. Southward shifting of the desert margin helped trigger the emergence of pharaonic civilization along the Nile, influenced the spread of pastoralism throughout the continent, and affects sub-Saharan Africa to the present day.     

Eighth millennium pottery from a prehistoric shell midden in the brazilian Amazon

The earliest pottery yet found in the Western Hemisphere has been excavated from a prehistoric shell midden near Santarém in the lower Amazon, Brazil. Calibrated accelerator radiocarbon dates on charcoal, shell, and pottery and a thermoluminescence date on pottery from the site fall from about 8000 to 7000 years before the present. The early fishing village is part of a long prehistoric trajectory that contradicts theories that resource poverty limited cultural evolution in the tropics.     

Soapstone artifacts: tracing prehistoric trade patterns in virgimna

Rare earth element abundances in soapstone from quarries and artifacts in eastern Virginia were determined by instrumental neutron activation analysis. By comparing these abundances it was possible to trace artifactual material to the outcrops which served as the source of this material during the first millennium B.C. Certain known sociopolitical boundaries in prehistoric Virginia were inferred to be older than previously assumed.     

Thermoluminescent determination of prehistoric heat treatment of chert artifacts

In recent years archeologists have become interested in the extent to which prehistoric peoples heat-treated chert prior to shaping it into tools. Thermoluminescent determination of the radiation dose accumulated by an artifact since it was formed or last heated provides a simple, reliable test for such heat treatment. This test can be applied to single artifacts without the need for raw source material for comparison. Results on 25 artifacts from four sites indicate that, for many chert sources, color and luster are not useful indicators of heat treatment by prehistoric peoples.     

Late quaternary environmental history of lake valencia, Venezuela

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate to low salinities and discharged water; the modern vegetation became established at that time. After 8500 years B.P., the lake twice ceased discharging as a result of reduced watershed moisture. The second of these drying episodes is still in progress and has been aggravated by human activities in the watershed.     

安徽淮河流域大汶口文化时期的原始农业初探

大汶口文化时期是安徽淮河流域新石器时代文化发展的重要阶段,也是该地区原始农业发展的关键时期。作者梳理近年来的植物考古研究成果,本文认为:安徽淮河流域在大汶口文化时期阶段实现生业经济由低水平食物生产向原始农业为主体的转变,粟、黍的种植在本地区不断普及,与原有的稻作农业传统融合,呈现出以稻粟并重为特色的稻旱兼作种植模式。原始农业的发展受到气候变化和文化传播、发展的双重影响,大汶口文化晚期气候条件的改善和考古学文化的发展促进了原始农业的快速发展,而原始农业的发展也推动了大汶口文化晚期的繁荣局面。     

Earthquake dating: an application of carbon-14 atom counting

Milligram-sized specimens of detrital charcoal from soil layers associated with prehistoric earthquakes on the Wasatch fault in Utah have been dated by direct atom counting of carbon-14 with a tandem Van de Graaff accelerator. The measured ratios of carbon-14 to carbon-12 correspond to ages of 7800, 8800, and 9000 years with uncertainties of +/- 600 years.     

An early center of bovine husbandry in southeast Asia

Non Nok Tha is a prehistoric site in northeast Thailand. The radiocarbon dates suggest that it was first occupied by at least 3500 B.C., and possibly as early as 5000 B.C. The deepest levels contain unexpectedly early evidence for rice cultivation and bronze casting. Multivariate and cultural analyses of the bovine bones suggest that the first inhabitants raised domesticated cattle. This is among the earliest evidence for bovine domestication known.     

Late glacial climate record of midwestern United States from the hydrogen isotope ratio of lake organic matter

A hydrogen isotope time series obtained from an analysis of organic matter extracted from a lake core in Kalamazoo, southwestern Michigan, reveals four distinct isotope stages within the last 12,000 years that can be interpreted in terms of oscillations between cold and warm, dry climates. The most dramatic are a cold phase between 12,000 and 9000 years before present (B.P.), a warm, dry period between 8500 and 2000 years B.P., a cold period between 2000 and 1000 years B.P., and a warming trend since 1000 years B.P. The warming trend of the last 1000 years is comparable in magnitude to the mid-Holocene warm phase.     

A 5000-year record of extreme floods and climate change in the southwestern United States

A 5000-year regional paleoflood chronology, based on flood deposits from 19 rivers in Arizona and Utah, reveals that the largest floods in the region cluster into distinct time intervals that coincide with periods of cool, moist climate and frequent El Ni?o events. The floods were most numerous from 4800 to 3600 years before present (B.P.), around 1000 years B.P., and after 500 years B.P., but decreased markedly from 3600 to 2200 and 800 to 600 years B.P. Analogous modern floods are associated with a specific set of anomalous atmospheric circulation conditions that were probably more prevalent during past flood epochs.     

The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas

Compelling archaeological evidence of an occupation older than Clovis (~12.8 to 13.1 thousand years ago) in North America is present at only a few sites, and the stone tool assemblages from these sites are small and varied. The Debra L. Friedkin site, Texas, contains an assemblage of 15,528 artifacts that define the Buttermilk Creek Complex, which stratigraphically underlies a Clovis assemblage and dates between ~13.2 and 15.5 thousand years ago. The Buttermilk Creek Complex confirms the emerging view that people occupied the Americas before Clovis and provides a large artifact assemblage to explore Clovis origins.     

大豆主要抗原蛋白对埃及胡子鲇肌肉营养成分的影响

在室内单循环控温养殖系统中,给初始体质量为(15.14±0.05)g的健康埃及胡子鲇(Clarias lazera)投喂以鱼粉为动物蛋白源,鱼油、玉米油、糊精为能源,纤维素为填充物配制的3种等氮(粗蛋白质量分数为40%)、等能(15.8 MJ/kg)的半精制饲料(其中β-伴大豆球蛋白的添加量为40 mg/g,大豆球蛋白的添加量为60 mg/g),研究了大豆中主要抗原蛋白对埃及胡子鲇肌肉营养成分的影响。饲喂6周后的调查数据表明:在本试验条件下,β-伴大豆球蛋白和大豆球蛋白使埃及胡子鲇肌肉中粗蛋白含量极显著下降(P<0.01),对肌肉中粗脂肪含量、粗灰分含量影响不显著(P>0.05);使肌肉中氨基酸总量、必需氨基酸总量和鲜味氨基酸总量下降,但与对照组差异不显著(P>0.05)。因此,在埃及胡子鲇幼鱼的配合饲料中,β-伴大豆球蛋白的含量超过40 mg/g、大豆球蛋白的含量超过60 mg/g时,对其肌肉营养成分具有一定的影响。     

PREHISTORIC ARCHEOLOGY,PAST, PRESENT AND FUTURE

The attempt has been made in the foregoing paragraphs to outline the whole history of prehistoric archeology: its crude beginnings in ancient times, its steadily accelerating progress during the past two hundred years, and its present achievements. Special emphasis has been placed on the r?le played by the discovery of surviving primitive industries in America and elsewhere in bringing about a rational attitude towards Stone Age antiquities and a beginning of their systematic investigation. The creation and growth of the organization and personnel promoting and conducting this world-wide research must be left untouched except to say that to-day probably every civilized country has its museums and university teaching staffs. Public interest in man's prehistoric past was never greater than to-day and only financial support is necessary to afford opportunity for the increasing numbers of young men and women who are constantly pleading for a chance to take part in the work. Accordingly, though the task before us is still very great it is not so hopeless as in the case of some other purely natural sciences like astronomy and entomology. For not only is the earth spherical and therefore limited in extent but man's period of occupancy is relatively short. In other words, while prehistoric archeology of necessity was one of the last special branches of research to get really under way, it is likely to be the first to finish its task. Indeed, if archeological investigations, historic and prehistoric, continue to progress at the same accelerating rate as in the past, it would seem that the next hundred years or so might easily see us in possession of all the essential facts. Those more or less indestructible facts or documents once in hand and the spade set aside, archeologists may have to change their titles to those of curators or something even less high-sounding. At all events, those professionally concerned may then devote their entire time to the permanent arrangement and final interpretation of all the available material culture traits, with a view to offering a visible demonstration of how, step by step from small beginnings, things as they are in the human world actually came to be so. That accomplished, when every one has become familiar with our recreated past, we shall be more nearly free and in the best possible position to give our whole-hearted attention to the really major creative problems of the present and the future.     

Origin and environmental setting of ancient agriculture in the lowlands of Mesoamerica

Archaeological research in the Gulf Coast of Tabasco reveals the earliest record of maize cultivation in Mexico. The first farmers settled along beach ridges and lagoons of the Grijalva River delta. Pollen from cultivated Zea appears with evidence of forest clearing about 5100 calendar years B.C. (yr B.C.) [6200 (14)C years before the present (yr B.P.)]. Large Zea sp. pollen, typical of domesticated maize (Zea mays), appears about 5000 calendar yr B.C. (6000 yr B.P.). A Manihot sp. pollen grain dated to 4600 calendar yr B.C. (5800 yr B.P.) may be from domesticated manioc. About 2500 calendar yr B.C. (4000 yr B.P.), domesticated sunflower seeds and cotton pollen appear as farming expanded.     

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.     

Chilean glacial chronology 20,000 to 11,000 carbon-14 years ago: some global comparisons

Chilean glaciers at a latitude of 41 degrees S reached a maximum extent about 19,400 carbon-14 years before the present (B. P.), shrank 50 percent by 16,000 years B. P., and readvanced to a smaller maximum after 14,800 years B. P. These fluctuations were closely in step with those of the Laurentide ice sheet east of the Mississippi River but differ somewhat from the accepted sequence in New Zealand. A corresponding pattern is not apparent in the Antarctic paleotemperature curve deduced from changes in oxygen isotope ratios.