Archaeology at the micro-scale: Micromorphology and phytoliths at a Swahili stonetown

Geoarchaeological and archaeobotanical techniques are increasingly applied to the study of urban and domestic space. However, they are seldom performed as part of an integrative approach, where the soil and botanical micro-records are used together. This paper presents the preliminary results of ongoing research at Songo Mnara in Tanzania that combines customised intra-site soil macro- and micromorphological analyses, chemical analysis and the study of phytoliths. The research is part of a multidisciplinary project on the use of urban space in Swahili stonetowns. By eliciting multiple datasets from Songo Mnara, this paper illustrates the potential of integrating geoarchaeology and archaeobotany to investigate the use of space in urban contexts. The approach is a novelty within the context of Swahili archaeology and an emerging one in Africa.Peer reviewe

European land-use at 6000 BP: from on-site data to the large-scale view

No abstract available

Past land-use and land-cover change: the challenge of quantification at the subcontinental to global scales

No abstract available

Charring effects on stable carbon and nitrogen isotope values on C4 plants: Inferences for archaeological investigations

Experimental studies demonstrated that charring affects stable isotope values of plant remains. Therefore, it is necessary to consider the impact of charring to reliably interpret δ13C and δ15N values in archaeobotanical remains before using this approach to reconstruct past water management, paleoclimatic changes, and infer paleodietary patterns. Research so far has focused mostly on C3 plants while the charring effect on C4 plants is less understood. This study explored the effects of charring on δ13C, δ15N, %C, %N, and C:N in grains of two C4 species, Sorghum bicolor (L.) Moench (NADP-ME) and Cenchrus americanus (L.) Morrone (heterotypic synonym Pennisetum glaucum (L.) R.Br.) (NAD-ME), grown under the same controlled environmental conditions (watering, light, atmospheric humidity). Sorghum and pearl millet grains were charred from 1 to 3 h at 200–300 °C. Comparing first the uncharred grains, the results show that sorghum has lower δ15N and higher δ13C values than pearl millet. This evidence is also recorded in the charred grains. The charring experiments indicate that the temperature to which the grains are exposed has a higher impact than time on the preservation, mass loss, %C, %N, C:N, and δ13C and δ15N values. Every 50 °C of increase resulted in significant increases of δ15N (+0.37‰) and of δ13C (+0.06‰) values. Increasing the duration of charring to 3 h resulted in significant changes of δ15N (+0.17‰) and no significant changes for δ13C (−0.04‰) values. The average charring effects estimated in our experiment is 0.27‰ (95% CI between −0.02 and 0.56) for δ15N and −0.18‰ (95% CI between −0.30 and −0.06‰) for δ13C. Considering the average values, our data show that pearl millet is more affected by charring than sorghum; however, according to the standard deviations, sorghum shows a greater variability charring effect than pearl millet. This study provides new information to correctly assessing the isotopic values obtained from ancient C4 crops, providing a charring offset specific for C4 plants. Furthermore, it suggests that NAD-ME and NADP-ME species present isotopic differences under the same growing conditions and this must be taken into account in analytical works on ancient C4 crops.This work was funded by the ERC Staring Grant RAINDROPS (G.A. n 759800) under the Horizon 2020 program of the European Commission. CASEs is a Quality Research Group funded by the Government of Catalonia (SGR00950-2021)

Global-scale comparisons of human land use: developing shared terminology for land-use practices for global change

Although archaeological data are needed to understand the impacts of past human land use on the Earth system, synthesis is hampered by a lack of consistent categories. We develop hierarchical and scalable land-use classifications for use across the globe

Inferências sobre Vegetação e Clima no Holoceno a partir de Fitólitos e Pólen da Lagoa do Macuco, Litoral Norte do Estado do Espírito Santo (Brasil)

[EN] An interproxy approach focused on phytoliths and pollen, including radiocarbon dating and sediment particle-size analyses, has been carried out at Lagoa do Macuco, Linhares municipality, Espírito Santo State, Brazil. Three pollen zones were identified: the first one (MAC-C I) indicates the presence of mangrove vegetation between 7700 cal yr BP and 4396 cal yr BP; the second one a displacement of the vegetation from the lower areas to the more elevated margins of the valley (MAC-C II, from between 4396 to 1287 cal. yr BP) and third one (MAC-C III), representing the period of the current lake evolution, between 1287 cal. yr BP and the present day. The displacement of the mangrove seems to be connected to the landward migration of the palaeo-estuary and the flooding of the lower parts of the valley, reflecting the relative sea-level highstand, which occurred after 7000 cal yr BP. The phytolith analysis indicated four main zone. The phytolith zone I (7700-7100 cal yr BP) did not show the presence of phytoliths. The phytoliths zone II (7100-3400 cal yr BP) indicates the presence of an open vegetation predominantly of grasses while phytolith zone III (3400-400 cal yr BP) shows a phase with more forested vegetation. Finally, the phytolith zone IV (400 cal yr BP to modern) has a decrease in tree cover and the setting of vegetation with a strong grasses component. Phytoliths indices indicate trends of humidity and temperature at a more local scale, allowing understanding the environmental conditions during the formation of the current lake.[PT] Uma abordagem interproxy focada na análise de fitólitos e de grãos de pólen, também incluindo datação 14C e análise granulométrica de sedimentos, foi aplicada ao estudo da Lagoa do Macuco, em Linhares no Estado do Espírito Santo. Foram identificadas três zonas polínicas definidas com base nas mudanças do registro polínico, a primeira (MAC-C I) indicando a presença de uma vegetação de mangue entre 7700 anos cal AP e 4396 anos cal AP, a segunda (MAC-C II) que representa o deslocamento da vegetação das áreas mais baixas para as partes marginais mais elevadas do vale (4396 anos cal AP - 1287 anos cal AP) e a terceira (MAC-C III) que representa o período da instalação do atual lago, entre 1287 anos cal AP e os dias atuais. O deslocamento do mangue parece estar conectado a migração em direção ao paleo-estuário e o alagamento das partes baixas do vale, refletindo a elevação do nível relativo do mar depois de 7000 cal anos AP. A análise fitolítica indicou quatro zonas principais. A zona fitolítica I (7700-7100 anos cal AP), não apresentou fitólitos. A zona fitolítica II (7100-3400 anos cal AP) indica a presença de uma vegetação predominantemente composta por gramíneas, enquanto a zona fitolítica III (3400-400 anos cal AP) mostrou uma fase com uma vegetação mais florestada. Finalmente, a zona fitolítica IV, (400 anos cal AP até os dias atuais) apresentou decréscimo da cobertura arbórea e uma estrutura de vegetação com forte presença de gramíneas em sua composição. Os índices fitolíticos indicaram tendência de umidade e temperatura em escala local permitindo a compreensão das condições ambientais durante a formação do lago atual.The authors express their gratitude to Vale and Sooretama Nature Reserves (Linhares, ES, Brasil) for the field support. This work received financial support by the São Paulo Foundation for Research (FAPESP), grant 2011/00995-7, and CNPq (Universal), grant 470210/2012-5.Peer Reviewe

Potentials and limitations for the identification of outdoor dung plasters in humid tropical environment: a geo-ethnoarchaeological case study from South India

© 2018, The Author(s). Dung has been an important material used by humans since at least the early Neolithic Period. It accumulated within domesticated animal enclosures and it was used as fuel and fertiliser as well as construction material. While the formers were studied in details, to date, the use of dung as a construction material received less attention. Here, we present a geo-ethnoarchaeological pilot study aimed at understanding the archaeological formation processes of outdoor dung-plastered floors and the possibility to identify dung markers. We studied two house terrace in a rural village from a humid tropical environment in South India (Western Ghats). Sediment samples were collected from the plastered terrace surfaces, the terraces embankment and from forest soil controls. Multi-proxy analysis of the samples included infrared spectroscopy, phytolith and dung spherulite quantification, loss on ignition, elemental analysis and micromorphological analysis. The plastering of the floors was made by mixing a quantity of dung with water and by spreading the slurry unevenly across the terrace. This result in formation of a 0.1- to 0.5-mm-thick dung crust that the analyses showed to be rich in humified organics but with very low concentrations of phytoliths and dung spherulites. The careless spreading of the dung slurry, however, resulted in localised deposition of dung lumps that displayed relatively high concentrations of phytoliths, dung spherulites, organic matter, phosphorus and strontium. The generally low preservation of dung markers seems to be related to pre- and post-depositional processes. Forest arboreal plants are low phytoliths producer, having therefore little input of these siliceous bodies in the animal faeces. Post depositional processes included trampling, sweeping and water runoff that caused severe mechanical weathering, resulting in the heavy decay of the dung crust and the removal of dung residues from the terrace surfaces. In addition, the acidic conditions of a humid tropical environment likely promoted the complete dissolution of dung spherulites. This study provides new data and insights on the potentials and limitations of dung identification in outdoor settings in humid tropical environments. We suggest possible directions for advancing the study of archaeological dung used as construction materials

The unexpected land use: rain-fed agriculture in drylands

Although excluded from most maps of current and past land use, dryland rain-fed (non-irrigated) agriculture has been and is pivotal to enhance resilience of human communities, and understand land-atmosphere interactions and regional climate in many parts of the world

High and medium resolution satellite imagery to evaluate late holocene human-environment interactions in arid lands: A case study from the Central Sahara.

We present preliminary results of an Earth observation approach for the study of past human occupation and landscape reconstruction in the Central Sahara. This region includes a variety of geomorphological features such as palaeo-oases, dried river beds, alluvial fans and upland plateaux whose geomorphological characteristics, in combination with climate changes, have influenced patterns of human dispersal and sociocultural activities during the late Holocene. In this paper, we discuss the use of medium- and high-resolution remotely sensed data for the mapping of anthropogenic features and paleo- and contemporary hydrology and vegetation. In the absence of field inspection in this inaccessible region, we use different remote sensing methods to first identify and classify archaeological features, and then explore the geomorphological factors that might have influenced their spatial distribution.EM201

The formation of fire residues associated with hunter-gatherers in humid tropical environments: A geo-ethnoarchaeological perspective

Tropical forests have been an important human habitat and played a significant role in early human dispersal and evolution. Likewise, the use of fire, besides being one of the exceptional characteristics of humans, serves as a marker for human evolution. While the use of fire by prehistoric hunter-gatherers is relatively well documented in arid and temperate environments, the archaeological evidence in humid tropical environment is to date very limited. We first review the archaeological evidence for hunter-gatherer use of fire in humid tropical environments and suggest that better understanding of formation processes is required. We present a geo-ethnoarchaeological study from South India, involving ethnography, excavations and laboratory-based analyses in order to build a new framework to study fire residues in humid tropical forests associated with hunter-gatherer's use of fire. Ethnographic observations point to a dynamic and ephemeral use of hearths. Hearths location were dictated by the social and ever-changing social dynamics of the site. The hearths deposited small amount of residues which were later swept on a daily basis, re-depositing ash and charcoal in waste areas and leaving only a microscopic signal in the original location. Particular acidic conditions and intensive biological activity within tropical sediments result in the complete dissolution of ash and bones while favouring the preservation of charcoal and phytoliths. Consequently, the identification of fire residues in humid tropical forests and the reconstruction of the human use of fire must involve multi-proxy microscopic analysis to detect its micro-signatures.This work was supported by the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007–2013) under REA agreement n° 623293 granted to D.E.F. at the McDonald Institute for Archaeological Research, University of Cambridge. Radiocarbon dating was also funded by the Exilarch’s Foundation for the DANGOOR Research Accelerator Mass Spectrometry Laboratory (D-REAMS)