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Multi-proxy analysis was performed on a radiocarbon-dated core, collected from a relic oxbow lake in theLimpopo River-plain, Mozambique, with the aim to reconstruct paleo-environment and past flooding of thelower river system over the past c. 800 years. An additional objective was to evaluate and investigate the potentialuse of different proxies as recorders of paleo-flooding events and paleo-environmental variability within thefloodplain. The proxies applied in this study were: mineral magnetic properties, grain-size distribution, organiccarbon content and diatom microfossil assemblages.We found that sediment grain-size and mineral magneticproperties of the minerogenic fraction were the most sensitive proxies in terms of detecting signals from highintensityriver-discharge events. In the 800 year long sequence, variations in sand content, magnetic susceptibilityand saturation isothermal remnant magnetization suggest at least four major flooding events at the siteduring the reconstructed period; in the mid-1200, late-1300, mid-1500 AD and during the last century. Thediatom proxy reflects the development of the site from an open oxbow lake to a mainly terrestrial area. Thediatom assemblage indicates that open lake conditions prevailed at the site between c. AD 1200–1400, withperiodic inundation by marine water, most likely due to late Holocene sea-level changes. From c. AD 1400 andonwards, diatoms were rarely deposited at the site, which indicates drier conditions. This was a result of soilformation and gradual in-filling of the lake, a processwhich possiblywas accentuated by a regionally dry climatesituation. Our study shows that oxbow lakes and the proxies used here have great potential for reconstructingflooding events, a knowledge that is crucial for potential prediction and mitigation of flooding events inMozambique in the future. Although chronological uncertainties limit comparisons to other paleoenvironmentalrecords, it seems that the flooding events recorded

The discovery of a child's skeleton in a Late Neolithic well in Sweden raises again the issue of watery rituals and human sacrifice in prehistoric societies. Analysis of diatoms from the right humerus and from the surrounding sediment indicated that the child died by drowning and had not simply been disposed of in the well after death. The scenarios of accidental drowning and murder are examined to account for this discovery. The preferred hypothesis, based on a comparative study of similar finds from north-western Europe, interprets this instead as a ritual sacrifice. The use of diatom analysis to establish drowning as the cause of death adds a new weapon into the armoury of forensic archaeology.

The development of a glacial lake impounded along the retreating, northeastern ice margin of the Fennoscandian Ice Sheet during the last deglaciation and environmental conditions directly following the early Holocene deglaciation have been studied in NE Finland. This so-called Sokli Ice Lake has been reconstructed previously using topographic and geomorphologic evidence. In this paper a multiproxy approach is employed to study a 3-m-thick sediment succession consisting of laminated silts grading into gyttja cored in Lake Loitsana, a remnant of the Sokli Ice Lake. Variations in the sediment and siliceous microfossil records indicate distinct changes in water depth and lake size in the Loitsana basin as the Sokli Ice Lake was drained through various spillways opening up along the retreating ice front. Geochemical data (XRF core-scanning) show changes in the influence of regional catchment geochemistry (Precambrian crystalline rocks) in the glacial lake drainage area versus local catchment geochemistry (Sokli Carbonatite Massif) within the Lake Loitsana drainage area during the lake evolution. Principal component analysis on the geochemical data further suggests that grain-size is an additional factor responsible for the variability of the sediment geochemistry record. The trophic state of the lake changed drastically as a result of morphometric eutrophication once the glacial lake developed into Lake Loitsana. The AMS radiocarbon dating on tree birch seeds found in the glaciolacustrine sediment indicates that Lake Loitsana was deglaciated sometime prior to 10 700 cal. a BP showing that tree Betula was present on the deglaciated land surrounding the glacial lake. Although glacial lakes covered large areas of northern Finland during the last deglaciation, only few glaciolacustrine sediment successions have been studied in any detail. Our study shows the potential of these sediments for multiproxy analysis and contributes to the reconstruction of environmental conditions

A combined ground-penetrating radar (GPR), drilling and diatom survey was carried out in order to characterize formation of the Kudrukula Stone Age Comb Ware archaeological site, northeast Estonia. A few decades ago a cultural layer was discovered, located within fine-grained sands of the right bank of the Kudrukula Stream an altitude of 1.25-1.60 m above sea level. The layer is 15-35 cm thick and composed of poorly sorted sand of intensive reddish colour with abundant arte- and ecofacts, human bones, burned hearthstones and charcoal pieces. Artefacts, in particular pottery, are well preserved and frequently present as large pieces. The Kudrukula site holds an exceptional position among other Stone Age coastal settlements in that it is not located directly on top of beach ridges, but is buried under similar to 3 m of sand. When the Kudrukula settlement existed the level of the Litorina Sea was similar to 6 m above present sea level, which is similar to 4.5 m above the present location of the cultural layer. The current research is used to describe the geological structure of the area to provide a perspective on the history of the cultural material, and reveals that the cultural material is not restricted to one layer/lens only because it is irregularly and widely distributed within the sands of Kudrukula. The GPR and diatom analyses show that the Kudrukula cultural material is redeposited, because it occurs within an ancient point-bar succession of a (Narva) river meander. Originally, the dwelling site had been located on top of the Narva-Joesuu sandy coastal ridges, which subsequently suffered erosion and the sand resedimented at the Kudrukula location. Good preservation of the cultural items shows that, after redeposition, they were buried fast, probably within a year. The present Kudrukula stream has cut into the floodplain of the ancient (Narva) river to expose the redeposited layer/lens., AuthorCount:8

Lake Duluti is a small, topographically closed crater lake located on the flanks of Mt Meru, northern Tanzania. Analyses of diatoms in three short sediment cores and four modern samples from Lake Duluti were used to infer past environmental changes. 210Pb and 137Cs activity profiles combined with AMS 14C dates provide the chronological framework. Weak agreement between the 210Pb and 14C records, together with dating uncertainty, precludes construction of precise age models. The modern diatom flora, from plankton and three periphytic habitats, is dominated by Aulacoseira ambigua (Grunow) Simonsen, Gomphonema parvulum (Kützing) Grunow and Nitzschia amphibia Grunow. All three cores display similar stratigraphic succession, but the relative ratio of habitats represented by the diatoms varies substantially between cores. Diatoms indicate that the oldest part of the record is characterized by relatively low lake level and swampy vegetation. In the late nineteenth or early twentieth century there was a rapid lake level rise and the swamp turned into an open-water lake. High lake levels have prevailed since that time.

The long-term responses of vegetation to climate variability are of relevance for predicting present and future vegetation change, and have implications for the management of savanna and riparian ecosystems. This paper explores the links between regional rainfall, hydrology and vegetation dynamics in the savannas and riverine forests of the lower Limpopo Valley, southern Africa, from 800 AD to the present, reviewing palaeoecological data (fossil pollen, spores, diatoms and lithology) from several hydrological systems in Kruger National Park (KNP), South Africa and Limpopo National Park (PNL), Mozambique. The PNL-KNP records show that riverine arboreal taxa expanded during wetter periods, including 800-1400 AD and after 1800 AD. Between 1400 and 1800 AD, grasses, savanna taxa and generalist taxa were favored over riparian taxa, a change that is linked with the onset of dry spells in the region (corresponding to the so-called Little Ice Age). The most extreme drought events around 1700 AD resulted in a marked decline of riparian forest taxa near Lake Mapimbi, KNP. In contrast, many water-scarce sequences away from the riverine environment, such as Radio Pan, Mafayeni Pan, Malahlapanga Pan and Lake Makwadzi show stable grassland vegetation throughout the last 1200 years. The results demonstrate the resilience of the grassland-savanna ecosystems to projected climate change with warmer and overall drier climate. The riverine forests are predicted to be more vulnerable especially as more extreme weather events are projected., AuthorCount:5

Stratigraphic variations in diatom composition and phytolith abundance in a sediment core from a small, hydrologically isolated waterbody, Lake Nhauhache, Mozambique, provide evidence of water-level fluctuations over the past 2,300 years. Ten AMS radiocarbon dates on bulk sediment samples show that the lake came into existence about 2,300 years ago and that it has dried out since then, but only for brief time periods. Changes in the diatom assemblage composition indicate that lake level fluctuated in response to shifting humidity conditions. The changes reflect wetter conditions ca. 300 BC-AD 800, more variable conditions between AD 800 and 1150, a distinct dry phase within the time span AD 1150-1700 and a return thereafter to more humid conditions until present. There is general agreement between the Lake Nhauhache record and other records from the Southern Hemisphere summer rainfall region. This suggests that sediments from small interdunal lakes, which are abundant along the coast of southern Africa, provide reliable, regional paleoenvironmental information about an area from which more such data are needed., AuthorCount:8

Changes in Holocene coastal paleo-environment and sea-level variations have been recorded in estuary sediments from Macassa Bay, southern Mozambique. Methods include analysis of fossil diatoms, sediment stratigraphy, mineral magnetic properties, stable carbon and nitrogen isotope composition and carbon and nitrogen content. The chronology, based on six AMS 14C dates, suggests a basal age of the sediment core of c 6600 cal BP (calibrated years Before Present). The multi-proxy dataset implies two phases when the site was experiencing marine conditions and tentative sea-level high-stands: 1) between c 6600–6300 cal BP which is contemporary with the last phase of the global transgression and the Holocene climatic optimum, and 2) between c 4700–1000 cal BP, a period when sea level curves from the region suggest occasional minor sea level high-stands. Between these phases (c 6300–4700 cal BP), the environment within the Macassa Bay estuary was less influenced by marine processes, and studied proxies indicate a freshwater phase associated with relatively low sea levels. After c 1000 cal BP, a terrestrial environment prevailed at the site, probably as a result of a combined effect of sea level lowering and high accumulation of organic peat within the estuary.

Our research, based on studies of different climate archives from Tanzania, Mozambique and South Africa, contributes information on changes in climate and vegetation over the past 24000 years. This time perspective, reaching beyond the information available from instrumental records is needed for a better understanding of regional global climate dynamics and issues surrounding environmental change, throughout Africa, and is a prerequisite for increasing climate forecasting capabilities for the region. We argue that African people have vast experience from living in a variable climate and research on past interactions between climate and societies demonstrate the significance of lessons learnt for present situations. Our findings, underline the complex interactions between climate/environment and societies that may lead to different developments in time and space. Considering the so called vulnerable continent, extended investigations of how African communities cope with and adapt to climatically driven changes is needed to increase the capability to realise the potential as well as the limitations, of modern African communities to adapt to future climate change.