scholarly journals Population collapse in Congo rainforest from 400 CE urges reassessment of the Bantu Expansion

2021 ◽  
Vol 7 (7) ◽  
pp. eabd8352
Author(s):  
Dirk Seidensticker ◽  
Wannes Hubau ◽  
Dirk Verschuren ◽  
Cesar Fortes-Lima ◽  
Pierre de Maret ◽  
...  

The present-day distribution of Bantu languages is commonly thought to reflect the early stages of the Bantu Expansion, the greatest migration event in African prehistory. Using 1149 radiocarbon dates linked to 115 pottery styles recovered from 726 sites throughout the Congo rainforest and adjacent areas, we show that this is not the case. Two periods of more intense human activity, each consisting of an expansion phase with widespread pottery styles and a regionalization phase with many more local pottery styles, are separated by a widespread population collapse between 400 and 600 CE followed by major resettlement centuries later. Coinciding with wetter climatic conditions, the collapse was possibly promoted by a prolonged epidemic. Comparison of our data with genetic and linguistic evidence further supports a spread-over-spread model for the dispersal of Bantu speakers and their languages.

1968 ◽  
Vol 9 (2) ◽  
pp. 191-211 ◽  
Author(s):  
D. W. Phillipson

The Early Iron Age people appear to have been responsible for the introduction into Zambia of pot-making, metallurgy and, less certainly, food production. Recent research has greatly increased the known number of Early Iron Age sites in Zambia and a number of regional variants have been defined, based largely on the typology of the associated pottery. Radiocarbon dates suggest that these groups are all to be dated to the first millennium a.d. and that they are contemporary with, and related to, the earliest known Iron Age in Rhodesia and some East African sites. It is suggested that the Early Iron Age people slowly spread into eastern Africa from an area west of Lake Tanganyika during the first few centuries a.d. Some related sites are known from this westerly region. This hypothesis can be compared with Oliver's interpretation of Guthrie's linguistic evidence; but the use of archaeological and linguistic arguments together is impossible until proof is available that the Early Iron Age people spoke Bantu languages.


Author(s):  
Kathryn M. de Luna

This chapter uses two case studies to explore how historians study language movement and change through comparative historical linguistics. The first case study stands as a short chapter in the larger history of the expansion of Bantu languages across eastern, central, and southern Africa. It focuses on the expansion of proto-Kafue, ca. 950–1250, from a linguistic homeland in the middle Kafue River region to lands beyond the Lukanga swamps to the north and the Zambezi River to the south. This expansion was made possible by a dramatic reconfiguration of ties of kinship. The second case study explores linguistic evidence for ridicule along the Lozi-Botatwe frontier in the mid- to late 19th century. Significantly, the units and scales of language movement and change in precolonial periods rendered visible through comparative historical linguistics bring to our attention alternative approaches to language change and movement in contemporary Africa.


Radiocarbon ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 693-700 ◽  
Author(s):  
Austin Long ◽  
Paul S. Martin ◽  
Humberto A. Lagiglia

A new set of radiocarbon dates from a rockshelter in Mendoza, Argentina addresses the question of the temporal overlap between the presence of an unidentified extinct ground sloth (cf., Mylodontidae) and evidence of human activity. Dung balls on the cave floor, evidently deposited by sloth, are overlain by charcoal, apparently of cultural origin. 14C dates, mostly on charcoal and dung from this shelter, calibrated using recently published curves, as well as the stratigraphy of the deposits from which the samples were collected, suggest that any co-occurrence of humans and ground sloths in this region was brief. In contrast, the single date on mylodon dermal ossicles from this shelter suggests significant time overlap. Replication of this date as well as obtaining new high-precision 14C analyses from this site will be the next priority.


1999 ◽  
Vol 36 (8) ◽  
pp. 1299-1314 ◽  
Author(s):  
Jan Risberg ◽  
Per Sandgren ◽  
James T Teller ◽  
William M Last

A 14.2 m long core was recovered from the southern Lake Manitoba basin. The sediment, consisting mainly of silty clay, was studied for siliceous microfossil content and mineral magnetics; 14 new accelerator mass spectrometry (AMS) radiocarbon dates provide chronological control of the paleoenvironmental history of the basin. The basal 5 m contains ice-rafted clasts and is largely barren of siliceous microfossils; these sediments were deposited when the lake was part of glacial Lake Agassiz. Sediments immediately overlying the barren part of the sequence contain AMS dates of 7700-7400 BP and reflect a dramatic change in conditions in the basin. Diatom abundances rise abruptly. Magnetic characteristics change substantially. The presence of freshwater taxa such as Stephanodiscus niagarae, together with brackish water diatoms, indicate that shallow, turbid, high-nutrient conditions with variable salinity occurred during the early part of the middle Holocene. Although climatic conditions throughout the northern Great Plains are known to have become drier and warmer during the mid-Holocene, there is a distinct change in diatom taxa in the Lake Manitoba sequence toward less saline conditions at this time. The presence of the riverine diatom Aulacoseira granulata in this interval supports previous conclusions that these freshwater conditions resulted from the northward diversion of the Assiniboine River into the basin. Following this, diatoms indicate an abrupt increase in salinity to >1500 mg·L-1 total dissolved solids between 4000 and 2600 BP, reflecting the diversion of the fresh waters of the Assiniboine River away from Lake Manitoba. Increasingly cooler and wetter conditions during the late Holocene, combined with differential isostatic rebound, caused a freshening of the lake during the late Holocene.


1993 ◽  
Vol 39 (1) ◽  
pp. 107-119 ◽  
Author(s):  
John Ogden ◽  
Rewi M. Newnham ◽  
Jonathan G. Palmer ◽  
Richard G. Serra ◽  
Neil D. Mitchell

AbstractTwenty-two plant species were identified from leaves, fruits, or flowers, and 41 taxa from pollen, present in a macrofossil (leaf) layer in a peat swamp formed on Pleistocene dunes on the Aupouri Peninsula in northern New Zealand. Eight genera of gymnosperms are represented. With the exception of Lagarostrobos colensoi, all tree species abundant as macrofossils are also common as pollen. Macrofossils enabled the on-site flora to be compared with the regional flora, represented by the pollen rain. Studies on leaf decomposition rates indicate bias toward sclerophyllous species in the macrofossils. Identification to species level and treering data from preserved kauri logs allow quantitative comparisons with similar extant communities. Current climatic conditions at those analogue sites are cooler (2° to 3°C), cloudier (11%), and much wetter (85%) than those currently prevailing on the Aupouri Peninsula. Dendrochronological results also suggest that the far north of New Zealand had a cooler, cloudier, and wetter climate at the time the fossil leaf assemblage was formed. Radiocarbon dates from possibly contaminated samples suggest that a diverse mixed gymnosperm/angiosperm forest, dominated by kauri (Agathis australis), was present about (or sometime before) 41,00034,000 yr B.P., when the leaf layer was formed. Similar temperature reductions have been postulated for this period in New Zealand by other authors.


1989 ◽  
Vol 26 (9) ◽  
pp. 1811-1825 ◽  
Author(s):  
Rolf W. Mathewes ◽  
Miriam King

Chilhil, Phair, Fishblue, and Horseshoe lakes in the southern interior of British Columbia were cored and analyzed for pollen. Phair Lake was also examined for plant macrofossils and aquatic molluscs. Two dated volcanic tephras (Mazama and Bridge River) are present in three of the four lakes and, together with radiocarbon dates, provide an absolute chronology for pollen-influx calculations and stratigraphic correlation. Abrupt changes in sediment type at Phair Lake about 5650 and 2000 years ago correlate with Neoglacial advances near the coast–interior transition. Pollen changes suggestive of moister conditions and the presence of an aquatic mollusc (Valvata sincera helicoidea) at Phair and Chilhil lakes are consistent with the Neoglacial evidence of cooler and wetter conditions after about 2400 years ago. The driest part of the Holocene was the early, pre-Mazama (ca. 6600–6800 years ago) interval, when the vegetation was more open and herb rich and the lake levels were lower than at present. Wetter climatic conditions appear in post-Mazama time, indicated by regional increases in the pollen of Tsuga heterophylla and other coastal and subalpine trees. Pollen-influx values for the Interior Douglas-fir Zone are broadly consistent at all sites, with values of < 2000 –8000 grains cm−2 year−1. Douglas-fir (Pseudotsuga menziesii) has been an important forest species in the study region throughout the Holocene.


2020 ◽  
pp. 195-208
Author(s):  
Yurii Shcatula ◽  
Volodymyr Votyk

The analysis of literary sources showed that interest in chickpeas is increasing, sown areas under this crop are expanding, and technological features for chickpea cultivation are changing. The yield of chickpea seeds to a large extent depends on the biological characteristics of the variety, fertilizers, compliance with the timing and methods of sowing, inoculation of seeds and the like. Much attention should be paid to the system of protection of chickpea agrocenoses from harmful organisms. Weak competition of chickpea plants with weeds is primarily due to the peculiarity of the development of this culture in the early stages, when there is an intensive development of the root system and slow - the aboveground part. In these early stages of their development, chickpea plants are not yet able to fully compete with weeds. The latter, on the contrary, are serious competitors, as they actively use nutrients, moisture and shade plants. High selectivity and herbicidal activity in chickpea crops were shown by soil preparations: Stomp, 33% k.e. (4.0 l / ha); Harness, 90% (1.5–3.0 l / ha); Optima frontier (0.8– 1.0 l / ha). Weed reduction was 85–90% and yield increase was 0.71–0.82 t / ha. Of the post-emergence herbicides in chickpea crops in conditions of mixed weed type, it was advisable to use Pulsar (0.5-0.9 l / ha) and Pivot (0.5-0.8 l / ha). Weed loss was 81.0–82.0% and yield increase was 0.72–0.76 t / ha. When using different herbicides, the yield of chickpea grain was in the range from 1.26 to 1.44 t / ha. The presence of chickpeas in crops leads to severe inhibition, especially in the initial stages of vegetation. The most effective and economically feasible at present is the use of a tank mixture of herbicides Harnes + Gezagard 500 FM (2.0 l/ha + 3.0-4.0 l/ha) which makes it possible to control a wide range of weeds and extend the duration of the protective shield preparations. Chickpea seeds ripen fairly evenly throughout the plant, the beans do not crack or crumble, the plants do not lie down, so when harvested by direct combining there are no problems. The growing season in chickpeas lasts 80-120 days, depending on the variety and growing conditions, so it is harvested in late July or early August after harvesting cereals. The yield of chickpea seeds varies in the range 1.4–2.7 t/ha, and with proper technology and climatic conditions it can be 2.5–3.5 t/ha. Key words: chickpeas, agrocenosis, technology, mineral fertilizers, weeds, herbicides, biological products, productivity.


2021 ◽  
Vol 5 (3) ◽  
pp. 287-304
Author(s):  
N.G. Razjigaeva ◽  
◽  
L.A. Ganzey ◽  
T.A. Grebennikova ◽  
T.A. Kopoteva ◽  
...  

The stages of development of small Solontsovskie (Shanduyskie) Lakes located in the middle mountains of the Central Sikhote-Alin within large landslides, formed on the slopes of the paleovolcano, are identified on the basis of complex study of the sediment section of the Nizhnee Lake. The ecological-taxonomic composition of the diatom flora, the botanical composition of peat have been analyzed, and the tendencies of lacustrine sedimentation depending on the different scale of hydroclimatic changes in the Late Holocene have been established. The age model is based on 6 radiocarbon dates. The temporary resolution for the reconstructions is 30–60 years. A comparison of the development of Nizhnee and Izyubrinye Solontsi Lakes was carried out, the stages of watering and shallowing of lakes were identified on the basis of their dynamics, which made it possible to restore the change in moisture in the middle mountains. Organogenic deposits in lacustrine basins accumulated at high rates (up to 1.7–1.9 mm/ year). The most detailed data were obtained for the last 2.6 thousand cal. yr BP based on the study of the sediment section of the Nizhnee Lake, which responded more sensitively to changing climatic conditions. Frequent changes in diatom assemblages and peat-forming plants indicate unstable hydroclimatic conditions with varying degrees of watering and drainage up to complete overgrowth of water bodies. According to the data of diatom analysis, a successive change in the trophicity of the lake was traced. A frequent change of sphagnum mosses of different sections with different trophic preferences was established. The main reason for the change in the hydrological regime of the lakes was variations in precipitation during the short-term climatic changes. The correlation of the identified paleoclimatic events with global data has been carried out. Cooling periods, as a rule, were accompanied by a decrease in moisture, but the Little Ice Age was wet due to an increase in precipitation.


Radiocarbon ◽  
1985 ◽  
Vol 27 (1) ◽  
pp. 52-73 ◽  
Author(s):  
Mieczysław F Pazdur ◽  
Romuald Awsiuk ◽  
Andrzej Bluszcz ◽  
Tomasz Goslar ◽  
Anna Pazdur ◽  
...  

The following list contains all age measurements of paleoenvironmental samples made from 1978 to the end of 1982 for the IGCP 158 Project “Paleohydrological changes in the temperate zone in the last 15,000 years,” Subproject B “Lake and mire environments” (Berglund, 1979), initiated by Bjorn Berglund and Leszek Starkel in 1976. The aim of this project was to reconstruct environmental changes related to climate and human activity in the temperate zone of Asia, Europe, and North America. Broad environmental reconstructions will be based upon a network of reference sites representing the natural geographic regions, distinguished by their geology, climate, vegetation, and other natural factors, according to Berglund (1979). The subdivision of Poland into 29 paleoecological units according to Ralska-Jasiewiczowa (1982) is presented in table 1, and in figure 1 where reference sites dated by 14C in our lab are also indicated.


2021 ◽  
Author(s):  
Ivett Pálfi ◽  
Mihály Pósfai ◽  
Ferenc Kristály ◽  
Daniel Veres ◽  
Fabien Arnaud ◽  
...  

&lt;p&gt;In the winter of 2017 three undisturbed sediment cores were retrieved from the Szemes Basin of Lake Balaton. The sediments were sampled for AMS &lt;sup&gt;14&lt;/sup&gt;C dating and we used 8 of the radiocarbon dates for age-depth modelling. Based on this, the investigated sediment sequence covers the entire Holocene and Late Glacial period and the bottom of the sediment is ca. ~16,000 cal yr BP old. X-ray fluorescence spectrometry (XRF) was used to reconstruct rapid changes in the element content of the lake sediment. The evaluation of the measured results makes it possible to reconstruct the changes in the discharge environment and lake water level that can be related to the climate and human impact. Based on the data, two major evaporation events can be observed at 5500 BP and 8100 BP. These results were also verified by oxygen isotope studies. To reconstruct the energy of the deposition environment, particle size analysis was performed. The obtained results confirmed that river sediments are common at the bottom of Lake Balaton sediments, while biogenic carbonate dominates in the upper, Holocene part of the sediment core. To identify each mineral phase in the sediment, X-ray diffraction (XRD) studies were used to determine the ratio of calcite to Mg-calcite. Based on our XRF measurements, focusing primarily on quantitative changes in magnesium and calcium, transmission electron microscopy (TEM) studies were performed, mainly in the Mg enrichment layer around 8100 BP. The precipitation of biogenic carbonate in Lake Balaton is still taking place, mainly in the form of calcite and Mg-calcite. Their relative proportions strongly depend on the Mg saturation of the water and the substrates on which they are separated. From our results we can draw conclusions about the possible previous deeper phases of the lake and the evaporation conditions of the water. The data obtained from transmission electron microscopy shows a good agreement with the results of the XRF measurement, the proportion of Mg-calcite increases around 8100 BP that likely indicate drier climatic conditions connectable to the well know 8.2 ka cal BP climatic reversal.&lt;/p&gt;


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