Search

International audience; This study presents a new precise radiocarbon chronology for the World Heritage site of Sarvestan (SW Iran). The monument is a key construction in the history of architecture because it is a typical Sasanian construction built during the late Sasanian or early Islamic period. Previous attempts to date the monument have suggested the ages ranging from the middle Sasanian (fifth century CE) to early Abbasid (ninth century CE) era. These age estimations are based on the analysis of architectural plans and techniques, and a few radiocarbon dates with very large age uncertainties. This paper presents the results of a systematic radiocarbon dating of timbers in the walls and charcoals in plaster mortars used in the main dome of the monument. It further applies wiggle matching technique and R_Combine function to substantially reduce the age uncertainties in wood sections. The results indicate that a major construction work was undertaken sometime between 658 and 683 CE, the century of the invasion of Fars by Muslim Arabs. This finding pushes back the age of Sarvestan for two centuries and suggests that the monument was built at the transitional period between Sasanian to Islamic era. Sarvestan would have been an architectural project designed andpossibly initiated during the late Sasanian period but mainly accomplished during the second half of the seventh century CE. It can thus be considered a late Sasanian heritage in early Islamic period. Its construction at a time of political unrest further suggests that some areas of Fars may have benefited from certain socio-political stabilities during the expansion of Islaminto the east at mid- to late seventh century CE

International audience; The late glacial-early Holocene transition is a key period in the earth's history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (southwestern Iran, near to Persepolis) during the late glacial-early Holocene transition (ca. 11 650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene, a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type, and Glyptotendipes pallens-type, suggests a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in Northern Hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the Younger Dryas highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the meltwater inflow from small local glaciers in the catchment basin is not excluded.; La transition tardiglaciaire-Holocène précoce représente une période clé de l'histoire de la terre. Si cette transition est bien étudiée en Europe, ce n'est toutefois pas le cas au Moyen-Orient, et les profils paléohydrologiques associés à des chronologies robustes demeurent rares pour cette région. Nous présentons un profil hydrobiologique intéressant qui montre un important changement environnemental s'étant produit dans la zone humide de Dasht-e Arjan (sud-ouest de l'Iran, près de Persépolis) durant la transition tardiglaciaire-Holocène précoce (vers 11 650 ans cal BP). Nous utilisons des subfossiles de chi-ronomidés (insectes : diptères) comme indicateurs de changements hydrologiques et pour reconstituer les fluctuations du niveau de lacs. Le milieu humide d'Arjan était un lac profond durant le Dryas récent, caractérisé par une prépondérance de taxons de type Chironomus plumosus/anthracinus adaptés aux conditions anoxiques des eaux profondes. Une baisse drastique (de plus de 80 % à moins de 10 %) de ces taxons au début de l'Holocène, combinée à la diversification de taxons littoraux de types Polypedilum nubeculosum, Dicrotendipes nervosus et Glyptotendipes pallens, indiquerait une baisse du niveau du lac et un milieu aquatique plus végétalisé. Nous comparons le profil des chironomidés d'Arjan à un profil semblable du nord-ouest de l'Iran. La signification paléoclimatique du profil, aux échelles locales et régionales, est ensuite abordée. L'augmentation des températures dans l'hémisphère nord au début de l'Holocène, inférée à partir de données géochimiques du NGRIP, est ce qui explique le mieux le passage de conditions de haut niveau du Dryas récent aux conditions de bas niveau de l'Holocène précoce dans la zone humide de Dasht-e Arjan. Un effet de l'apport d'eau de fonte de petits glaciers locaux dans le bassin versant n'est toutefois pas exclu. [Traduit par la Rédaction] Mots-clés : Dryas récent, changement climatique, karst, changement du niveau des lacs, Zagros.

International audience; Sedimentological (dry density, micro-fa-cies analysis on thin-slides, X-ray diffraction, layer counting) and elemental analyses (X-ray fluorescence) of a 3.5-m-long sediment core (MAH-B) from saline Lake Maharlou (SW Iran) were used to infer hydrological changes over the last * 3800 years. The sediment consists of thin, alternating beds of evapor-ites (halite, gypsum), carbonates (calcite, aragonite) and detrital minerals (quartz, muscovite, chlorite). We interpret the data with respect to three main hydrologic conditions: (1) nearly complete desiccation of the lake, marked by frequent halite layers, (2) hypersaline conditions marked by gypsum abundance, (3) wet conditions, characterized by high river-borne terrige-nous sediment input with high potassium content. Distinct flood layers indicate fluvial activity. From about 3800-2000 cal year BP, terrigenous sediment supply was high, with peaks at 3700-3650, 3500-3450, and 3400-3250 cal year BP. Evaporative conditions were not common. From ca. 2000 cal year BP to present, detrital minerals are less abundant, and the increase in gypsum abundance suggests drier climate with enhanced evaporation. Frequent desiccation events occurred from 1100 to 700 cal year BP. The late Holocene hydrology of Lake Maharlou corresponds well with records of dune formation and phases of river alluviation in Iran and the Arabian Peninsula, and with regional speleothem records. In addition to the influence of climate change on the lake hydrology, ancient humans modified water drainage in the catchment. Periods of subterranean tunnel (qanats) use correspond to dramatic shrinkage of the water body. We propose that climate changes drove long-term water shortages that were enhanced by anthro-pogenic activities, leading to more frequent desiccation of the lake during the last millennium.