Holozäne Klimaevents in Nordarabien - Umweltwandel und Reaktion des Menschen
Zusammenfassung der Projektergebnisse
The project CLEAR provides detailed palaeoclimatic and palaeoenvironmental interpretations from continuous palaeolake sediments at Tayma, northern Arabia, that cover the early to mid-Holocene. The age-depth model of the palaeolake sequence is based on AMS radiocarbon dating of 38 samples (mostly concentrated pollen), as well as a tephrochronological anchor identified close to the base of the Tayma sediment record (the central Anatolian 'S1'-tephra dated at 8983 plus minus 83 cal yr BP). A floating varve chronology of 650 plus minus 40 varve years helps to refine the Bayesian model within the varved section between 8550 and 7900 plus minus 40 cal varve yr BP. Wetland and lake sediments were deposited in the Tayma basin during the early to middle Holocene from ca. 9250 to 4200 cal yr BP, reflecting increased humidity in the northern Afro-Arabian region. From 9250 to 8800 cal yr BP, the clastic sedimentation and prevailing desert vegetation imply that climate was still relatively arid. At ca. 8800 cal yr BP, the in-situ deposition of the littoral, brackish-water ostracod Cyprideis torosa at the central drilling location and initial spread of grassland indicate the initial establishment of a perennial and increasingly productive water body. At ca. 8550 cal yr BP, the formation and preservation of varves in the Tayma lake started, evidencing a deep and stratified lake that persisted for a period of 650 plus minus 40 varve years. This is supported by remnants of shoreline deposits all around the basin, indicating a depth of c. 17 m and size of c. 20 m2. From ca. 8300 to 7950 cal yr BP, outstandingly high production of organic matter in the lake and strongest reduction of the dry-season evaporation characterize the most humid period during the entire Holocene at Tayma, supported by the distinct change in varve composition from evaporation-driven aragonite varves to productivity-fuelled diatom-aragonite varves. At ca. 7950 cal yr BP, the ceasing presence of diatom and aragonite laminae, more abundant clastic quartz grains from aeolian influx, and the first appearance of gypsum reflect a rapidly declining lake level. Thereafter, the mostly evaporitic-clastic sediments, in accordance with the replacement of grassland by more drought-resistant desert vegetation based on pollen, redraw prolonged aridification during the course of the mid-Holocene that ultimately led to sabkha development in the Tayma basin at ca. 4200 yr BP. First significant man-environment interaction might be indicated by a rapid increase in delta15N at about 8550 cal yr BP with the beginning of the varved phase, which could be induced by human or animal manure and sea birds with increasing delta15N depending on trophic state. In addition, increased concentrations of long-chain n-alkanes and faecal biomarkers suggest grassland expansion and probably human occupation. While the rise of n-alkane concentrations predates the onset of varved sediments by about one century, the increase in faecal biomarker coincides with the beginning of varve preservation. The pollen spectra of Tayma show the persistence of desert vegetation during the early and mid-Holocene (c. 9300-4700 cal yr BP), also during 8550 and 7950 cal yr BP. A distinct and rapid environmental change is indicated c. 8000 cal yr BP. Charred plant remains point to human presence at the oasis of Tayma, corroborated by archaeological findings, locally and in the wider region. About 1000 to 2000 years later, the beginnings of fruit cultivation at the oasis of Tayma (ca. 7000 cal yr BP) and a bead production centre indicate significant socio-culture changes and more modified subsistence strategies.
Projektbezogene Publikationen (Auswahl)
- 2016. Holocene vegetation, climate, land use and plant cultivation in the Tayma region, northwestern Arabia. In: Luciani, M. (ed.), The Archaeology of North Arabia – Oases and Landscapes. Proceedings of the International Congress held at the University of Vienna, 5-8 December, 2013 (=Oriental and European Archaeology Vol. 4). Austrian Academy of Sciences Press, Vienna, pp. 57-77
Dinies, M., Neef, R., Plessen, B., Kürschner, H.
- 2017. How to discriminate athalassic and marginal marine microfaunas? Foraminifera and other fossils from an early Holocene continental lake in northern Saudi Arabia. Journal of Foraminiferal Research 47, 175-187
Pint, A., Engel, M., Melzer, S., Frenzel, P., Plessen, B., Brückner, H.
(Siehe online unter https://doi.org/10.2113/gsjfr.47.2.175) - 2017. Implications of S1 tephra findings in Dead Sea and Tayma palaeolake sediments for marine reservoir age estimation and palaeoclimate synchronisation. Quaternary Science Reviews 170, 269-275
Neugebauer, I., Wulf, S., Schwab, M.J., Serb, J., Plessen, B., Appelt, O., Brauer, A.
(Siehe online unter https://doi.org/10.1016/j.quascirev.2017.06.020) - 2017. Lakes or wetlands? A comment on ‘The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons’ by Enzel et al. Global and Planetary Change 148, 258-267
Engel, M., Matter, A., Parker, A.G., Parton, A., Petraglia, M.D., Preston, G., Preusser, F.
(Siehe online unter https://doi.org/10.1016/j.gloplacha.2016.11.001) - 2017. Ostracod fauna associated with Cyprideis torosa – an overview. Journal of Micropalaeontology 36, 113-119
Pint, A., Frenzel, P.
(Siehe online unter https://doi.org/10.1144/jmpaleo2016-010) - 2017. Salinity-dependent sieve pore variability in Cyprideis torosa: an experiment. Journal of Micropalaeontology 36, 75-62
Frenzel, P., Ewald, J., Pint, A.
(Siehe online unter https://doi.org/10.1144/jmpaleo2016-009) - 2018. Early to middle Holocene vegetational development, climatic conditions and oasis cultivation in Taymāʾ: First results from pollen spectra out of a sabkha. In: Eichmann, R., Hausleiter, A., al-Najem, M. (eds.), Taymāʾ I: Archaeological Exploration, Palaeoenvironment, Cultural Contacts. Archaeopress, Oxford, pp. 128-144
Dinies, M., Neef, R., Kürschner, H.
- 2018. Oase Tayma – vom Garten zur Stadt? Archäologie in Deutschland 2/2018, 14-19
Hausleiter, A., Dinies, M., Prust, A.
- 2018. Palaeoenvironmental changes at Taymāʾ as inferred from sabkha infill. In: Eichmann, R., Hausleiter, A., al-Najem, M. (eds.), Taymāʾ I: Archaeological Exploration, Palaeoenvironment, Cultural Contacts. Archaeopress, Oxford, pp. 61-84
Engel, M., Klasen, N., Ginau, A., Patzke, M., Pint, A., Frenzel, P., Brückner, H.
- 2019. Holocene ecology in NW Arabia: Biotic resources and plant cultivation. In: Nakamura, S., Adachi, T., Abe, M. (eds.), Decades in Deserts: Essays on Western Asian Archaeology in Honor of Sumio Fujii. Rokuichi Shobou, Tokyo, pp. 205-214
Dinies, M.
