ANR OASIWAT - Origin, mutations and dynamics of Southeastern Arabia oases: Soil/water availability and management for the last 5 millennia

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The project OASIWAT aims to understand the social and environmental factors that have contributed to the development, mutation and durability of oases in Southeast Arabia since the 3rd mil. BC until today.

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Project log

L. Purdue
added 3 research items
Oases are subject to decreasing resources and changing human activities. Fully aware of their rich heritage, the United Arab Emirates (UAE) have undertaken work to preserve and revitalize these oases. However, there is a clear lack of understanding of the dynamic links between climate change, hydraulic and agricultural management, and socioeconomic activities. To clarify these links, our team conducted a systematic geoarchaeological, geophysical, spatial, and chronological study of the Masafi oasis, UAE. Results indicate the existence of a natural humid area as early as the late Pleistocene (~18 cal ka BP). These conditions persist during the early-mid Holocene with drainage activation and soil development (~12–6.3 ka). During the late Holocene, after the emergence of the “artificial” oasis around ~3250 cal yr BP, cycles of intense management suggesting water availability (~3250–2380 cal yr BP; 550 cal yr BP) alternate with episodes of fluvial detritism (~2380–1870 cal yr BP; >550 cal yr BP) and scattered evidence of farming activities with complex hydroclimatic signatures (~2300–550 cal yr BP). These results, together with regional environmental data, indicate that water and soil resources were available and exploited strategically throughout the Holocene despite adverse climatic conditions, and the oasis of Masafi could have acted as a desert refugium .
Abstract In order to understand the role of water resources in the establishment and long-term evolution of settlements investigated by the French Archaeological Mission in the UAE in the oasis of Masāfī, wells and springs of all periods, identified at the surface and in stratified contexts, were mapped and studied thanks to a multidisciplinary approach combining archaeology, geomorphology, geoarchaeology and ethnography. Our study demonstrates that: – The Masāfī oasis was located in a specific geological setting entailing the accumulation of groundwater resources at reachable depth. – The groundwater resources remained rather stable from the mid second millennium BC to the second half of the twentieth century AD. In this respect, the apparent abandonment of the oasis during some periods cannot be explained by water depletion. – The groundwater resources have decreased sharply since the second half of the twentieth century AD, due to the introduction of new water extraction technologies, motor pumps and then drillings, as a result of the modernisation and industrialisation of UAE economy. Our study also stresses the importance of well and spring irrigation in the development of the sedentary settlements in south-eastern Arabia, technologies that have often been neglected in the regional archaeological literature in favour of the qanāt. KEYWORDS geoarchaeology, geomorphology, oasis, spring, water management, well
Runoff farming is a key hydro-agricultural strategy that has proven efficient in arid areas. Research in Arabia on the function, development, maintenance, durability and abandonment of this technology is scarce. A multiproxy investigation (cartography, sedimentology, pedology, geochemistry, paleo-ecology and chronology) was conducted on a recently abandoned terraced area in Rustaq, Northern Oman. The aim was to characterize the formation, function and management of this runoff system and the driving factors behind its success. Cycles of cultivation were identified during the Iron Age II/III periods (specifically 750–450 BCE), the Early Pre-Islamic Period (PIR) (specifically 350–200 BCE), the Early and Middle Islamic periods (specifically 8–10th C CE, 13th-14th C CE) and the late Islamic period (specifically 17th C CE and later). This expansion and perenniality was possible thanks to: 1- available water (local to micro-regional orogenic precipitation despite a regional aridification during these periods); 2- suitable soils (weathered geological outcrops, probable aeolian /dust particles); 3- a system of production combining crops and husbandry; 4- a progressive increase in agricultural specialization (crops grown and techniques) in parallel with a diversification in hydraulic technology. These results are to some degree in accordance with known phases of settlement intensification and economic growth, but also reveal the persistence of small-scale rural livelihoods during periods of harsh conditions for which archaeological traces are very scarce.
L. Purdue
added a research item
Oasis soils result from the combined action of natural and anthropic processes, and thus constitute valuable systems for the understanding of human–environment trajectories over the millennia. The present research aims to develop the study of ancient oasis soils by identifying proxies to detect past agricultural practices. Ten reference pits were dug in Masafi, in both cultivated plots (irrigated plots with palm trees/fruit trees/cereals; manure/ashes/carbonates) and abandoned ones. Bulk sediment samples were analysed for geochemistry/pedo‐sedimentary studies: inductively coupled plasma‐optical emission spectrometry, loss on ignition, pH, electrical conductivity, grain size and magnetic susceptibility. This multiproxy approach enabled the creation of a soil typology of oasis agricultural modes. Irrigation and liming lead to salinisation, particularly in a B‐horizon. Manure creates a hortic horizon, enriched in P and Zn. Ashes can be detected with a simultaneous increase of magnetic and salinity values. Soils in plots with fruit trees/cereals are not distinguishable from those with palm monoculture. Weathering was identified on the basis of the enrichment in Al, Ti, K Na, Ni, Cr and Fe, whereas proxies of ancient practices seem to be preserved after 15 years of abandonment. As leaching processes appear to be limited to the first 50 cm, the durability of soil signatures depends on how they were buried.
Maël Crépy
added 2 research items
Abstract The following paper aims to show that geomorphology can provide, from a Niche Construction Theory (NCT) perspective, a contribution to the study of the transition from refugia to oases in aridlands using case-studies in 3 regions: 1-Kharga basin (Egypt), 2-South Tunisia and east Algeria, 3-Northeast part of the United Arab Emirates. This study shows how we can work on former human constructed niches and their evolution through time thanks to research based on geomorphological typology at a landscape scale. It also examines the renewal that NCT brings to geomorphological and geographical research on anthropogenic landscapes by providing an integrative way of describing interactions and retroactions between societies and their niches. Résumé L'article vise à analyser les apports de la géomorphologie à l'étude de la transition de refuge à oasis en milieu aride dans le cadre de la Théorie de la construction de niche (TCN). Trois régions ont été sélectionnées : 1-la dépression de Kharga (Égypte) ; 2-la Tunisie du Sud et l'est de l'Algérie ; 3-le nord-est des Émirats arabes unis. L'établissement d'une typologie géomorphologique à l'échelle du paysage permet d'étudier d'anciennes niches construites par les humains et leur évolution au cours du temps. Par ailleurs, il apparaît que la TCN apporte un renouveau pour la recherche géographique et géomorphologique portant sur les paysages anthropisés en proposant une approche intégrée des interactions et rétroactions entre les sociétés et leurs niches.
Sophie Costa
added a research item
Les oasis, espaces de polyculture intensive irrigués en milieu aride à semi-aride, sont caractérisées à la fois par des conditions physiques naturelles contraignantes mais aussi par les choix et mises en oeuvre anthropiques qui les façonnent. Ces espaces sont donc à l'équilibre entre différents facteurs socio-environnementaux : contraintes morpho-climatiques, variabilité des ressources, mais aussi dynamiques de peuplements, système socio-économique et développement technologique. L'oasis constitue un lieu privilégié pour l'enregistrement et la lecture des trajectoires homme-milieu au cours des millénaires. L'oasis de Masafi est fouillée depuis 2007 dans le cadre de la Mission archéologique Française aux Emirats Arabes Unis (dir. S. Méry). Ces fouilles ont permis la découverte de vestiges de l'Age du Bronze et de l'époque Islamique tardive mais surtout d'une occupation importante de l'Age du Fer, qui semble s'être structurée autour d'un espace central irrigué et cultivé 2. L'ouverture de sondages géoarchéologiques au sein de la zone agricole actuelle, menée depuis 2014 et aujourd'hui dans le cadre de l'ANR OASIWAT 3 (dir. L. Purdue), a mis en évidence des phases d'emprises et de déprises agraires synchrones ou non aux différentes occupations connues. A travers l'analyse d'une de ces séquences stratigraphiques, notre approche vise à mieux caractériser ces phases et à approfondir les interprétations archéologiques en terme de gestion des sols. Des référentiels ont été construits sur le terrain et une étude mêlant analyses pédo-sédimentaires (pertes au feu 30, 105, 450 et 950°C ; pH et conductivité électrique ; susceptibilité magnétique) et géochimiques (ICP-OES) a été menée en laboratoire.
L. Purdue
added an update
Project goal
The project OASIWAT aims to understand the social and environmental factors that have contributed to the development, mutation and durability of oases in Southeast Arabia since the 3rd mil. BC until today.
Background and motivation
Tasks :
The project OASIWAT aims to better understand past oases and agricultural societies faced with hydro-climatic and soil constraints, as well as contribute to the ongoing and necessary debate on their durability and preservation.
The project will focus on 3 major oases in the Hajar Mountains (Oasis of Masafi-Emirates of Fujairah and Ras al Khaimah – Dir J. Charbonnier, Oasis of Rustaq-Sultanate of Oman – Dir. D.Kennet, and Oasis of Dhayah, Khatt and Shimal-Emirate of Ras al Khaimah – Dir. L. Purdue), selected for their unique geographical location in southeastern Arabia (resources, climatic record), the presence of well-preserved deposits and the possibility of creating solid references.
This project will propose an innovative reconstruction of these landscapes through the systematic diachronic and integrated study of oasian agro-hydrosystems which compose them, and that we suspect being an adaptive answer to demographical, hydrological and morpho-sedimentary constraints. This study will also be confronted to local and regional data on morphological, climatical and human evolutions (settlement pattern and landscape organisation) in the Hajar mountains.