Quaternary Saline Lakes
Published:January 01, 1994
Two cores were recovered from deposits of the crater lake at Malha, in NW Sudan. One core was taken in the center of the lake (Core B), the other from a more marginal area (Core Y). In both cores, two main units are distinguished, each comprising the sediments of three distinct lacustrine phases. The first three lake stages (Periods I, II and III), all ending with lowstands or phases of complete dryness, are characterized by the deposition of mainly laminated sediments in a meromictic lake. During Periods IV, V and VI, the lake was holomictic and hyper- to mesosaline.
Mineral magnetic data for the cores allow us to trace several correlatable horizons that coincide with boundaries between the main lacustrine phases. Most peaks in magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM) are accompanied by shifts of the reverse field ratios to more negative values. These features indicate an increased supply of coarser grained detrital material to the coring sites, and correspond to periods when lake levels were either fluctuating or very low.
Only two radiocarbon dates are available for the entire Malha record: 8,290 ± 155 l4C years BP for 921-cm depth in Core Y, and 2,940 ± 70 l4C years BP for 643-cm depth in Core B. These two dates imply that the first lake desiccation, at the end of Period I, took place at ~7,000 years BP, and that the second lake desiccation, marking the boundary between Periods III and IV, occurred at ~2,200–2,300 years BP.
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Sedimentology and Geochemistry of Modern and Ancient Saline Lakes Models
Sedimentology and Geochemistry of Modern and Ancient Saline Lakes - This volume of papers grew out of a four-day symposium entitled ?Sedimentary and Paleolimnological Records of Saline Lakes? held at Saskatoon, Canada in August, 1991. The aim of this Special Publication is to bring together selected papers from this conference that deal specifically with the sedimentological, inorganic geochemical, and hydrological aspects of salt lakes and their stratigraphic records. This volume is divided into four sections. The first section contains papers that deal with modern saline lakes. The second section contains papers dealing with sedimentation and diagenesis of late Quaternary salt lakes. The third and fourth sections contain papers devoted to ancient (pre-Quaternary) Lacustrine sequences.