Found 30 datasets

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Un­ter­su­chung des Se­di­ment­be­ckens in Azraq, Jor­da­ni­en mit­tels Ra­dio­ma­gne­to­tell­u­rik und Gleich­strom­geo­elek­trik


Joint-Inversion von Transient Elektromagnetik und Gleichstromgeoelektrik Daten aus Azraq/Jordanien: Untersuchung von Static Shift Effekten

Aufgrund von oberflächennahen Inhomogenitäten können Static Shift Effekte auftreten. Das heißt, dass es zu einem parallelen Versatz von Sondierungskurven der Gleichstromgeoelektrik aufgrund von Aufladungseffekten kommen kann, wenn sich Ladungen an einer kleinen, oberflächennahen Inhomogenität ansammeln und aufgrund ihres elektrischen Feldes das elektrische Feld des Senders verzerren. Der Einfluss von Static Shift kann mit Einschränkung durch eine ergänzende Messung mit alternativen Verfahren, die keine...

A resistivity-depth model of the central Azraq basin area, Jordan: 2D forward and inverse modeling of time domain electromagnetic data

The focus of this thesis is the geophysical exploration of the central part of the Azraq basin in the northeastern desert of Jordan. In addition to common 1D inversion techniques, further 2D forward modeling strategies and a rarely used 2D inverse modeling scheme are applied to transient electromagnetic data. The Azraq area is of potential interest for palaeoclimatical and archaeological research in the frame of the interdisciplinary Collaborative Research Centre 806, entitled "Our Way to Europe" (CRC 806)....
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Investigation of the Azraq Basin, Jordan using Integrated Geoelectrical Techniques: 2D Modeling of Transient Electromagnetic Data

The Eastern Mediterranean has been the passageway for human migration from Africa to the Middle East, the Balkans and Europe. The Azraq basin in the eastern desert of Jordan has been a major spot for human settlements since the middle Pleistocene. The former lake in the basin center has developed to a 10 km × 10 km large hyper-saline alluvial mudflat, the Qa’ Al Azraq. In the basin center thick sequences of alluvial sediments, consisting mostly of clay and various evaporates, are deposited. We utilized the...
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Investigation of the Azraq Basin in the Eastern Desert of Jordan using Integrated Geoelectrical Techniques

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Geophysical field data recorded in Azraq, Jordan in 2011/2012

The central loop transient electromagnetic data were recorded in the central Azraq basin area, Jordan in two field surveys in 2011 and 2012. Two transects 5 km and 7 km long transects were investigated from the peripherie of the Azraq mudflat across its center. In total 150 soundings were recorded using either a 100x100 m transmitter loop for deep investigations down to approx. 120 m depth, or a 50x50 transmitter loop for fast transmitter turn-off times and shallow investigation. The data is processed, i.e....
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Investigation of the Azraq sedimentary basin, Jordan using integrated geoelectrical and electromagnetic techniques doi

The Eastern Mediterranean has been used as a passageway for human migration from Africa to the Middle East, the Balkans and Europe. The Azraq basin in the eastern desert of Jordan has been a major spot for human settlements since the middle Pleistocene. The former lake in the basin centre has developed to a hyper-saline alluvial mudflat, the Qa’ Al Azraq. In the mudflat thick sequences of alluvial sediments are deposited. Such sediment successions are promising archives used for reconstructing a...
Keywords: GQT2
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Holozäne Umweltrekonstruktion und Kulturgeschichte der Sahara: Perspektiven aus der sudanesischen Wüste


Aquatic community response in a groundwater-fed desert lake to Holocene desiccation of the Sahara doi Spatial

The finely laminated sediment record of a permanent, hypersaline, desert oasis lake in the Ounianga region of northeastern Chad presents a unique opportunity to document the hydrological evolution of this groundwater-fed aquatic ecosystem during mid- and late-Holocene desiccation of the Sahara. In this study we reconstruct long-term changes in zoobenthos and zooplankton communities of Lake Yoa as their early-Holocene freshwater habitat changed into the hypersaline conditions prevailing today. Chironomid...
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Response to Comment by Brovkin and Claussen on “Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years” doi

The Lake Yoa record and archaeological data provide adequate evidence that mid-Holocene aridification did not occur abruptly across all of North Africa. Modeling results on the issue of abrupt versus gradual desiccation of the Sahara are sufficiently diverse that paleoecological data from a continuous natural archive can usefully guide the evaluation of model parameters responsible for this diversity.
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Sedimentation changes in a complete Holocene lacustrine record in the Sahara: Varve thickness, seasonality and event layers – Problems of identification, interpretation and chronology. Spatial

Lake Yoa (19.03°N, 20.31°E, 380 m a.s.l.) is a groundwater-fed lake in the hyperarid eastern Sahara halfway between the Tibesti Mountains and the Ennedi plateau. Kröpelin et al. (2008) revealed that the bottom sediments contain a unique archive of climatic and environmental change in the Earth´s major desert. The 7.5 m sediment record of OUNIK03/04 which covers 6,100 years has been extended to a maximum drill depth of 15.7 m during a 2010 coring campaign within the framework of the Collaborative...
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Neues aus der sudanesischen Sahara