Two high levels of continental waters in the southern Tunisian chotts at about 90 and 150 ka

Journal Article · Sun Oct 01 00:00:00 EDT 1989 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1989)017<0922:THLOCW>2.3.CO;2· OSTI ID:7135775

Causse, C ^[1]; Coque, R ^[2]; Fontes, J Ch; Gasse, F; Gibert, E; Zouari, K ^[3]; Ouezdou, H B ^[4]

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1. CNRS Luminy, Marseille (France)
2. Institut de Geographie, Paris (France)
3. Universite Paris-Sud, Orsay (France)
4. INRST, Hammam-Lif (Tunisia)

Uranium and thorium content and activity ratios were measured on 20 samples (19 molluscs and 1 calcareous concretion) from the Great Chotts in southern Tunisia. Results were studied by the isochron method and by age frequency histograms. They suggest that two major flood episodes took place about 150 and 90 ka. Uranium activity ratios indicate a ground-water supply of continental origin, in agreement with biological indicators, which show large variations in salinity from fresh to marine-like conditions. The existence of a lacustrine phase, radiocarbon dated to 17-40 ka, as previously suggested for the northern Sahara, is highly questionable.

• OSTI ID: 7135775
• Journal Information: Geology; (USA), Vol. 17:10; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC DEPOSITS
HYDROLOGY
TUNISIA
AGE ESTIMATION
GEOLOGIC HISTORY
GROUND WATER
ISOTOPE DATING
ISOTOPE RATIO
MOLLUSCS
ORIGIN
PALEOCLIMATOLOGY
SALINITY
THORIUM
URANIUM
ACTINIDES
AFRICA
ANIMALS
AQUATIC ORGANISMS
DEVELOPING COUNTRIES
ELEMENTS
HYDROGEN COMPOUNDS
INVERTEBRATES
METALS
OXYGEN COMPOUNDS
PALEONTOLOGY
WATER
580000* - Geosciences