Micromorphological Study of a Sediment Core from the Malha Crater Lake, Sudan

Mees, Florias; Stoops, Georges

doi:10.1016/s0166-2481(08)70341-6

Cited by 3 publications

(1 citation statement)

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“…Some microscopic characteristics of the sediment are discussed in more detail by Mees & Stoops (1990). The geology of Malha Crater, previously described by Colchester (1927) and Sandford (1935b), is treated by Nijs (1986).…”

Section: Introductionmentioning

confidence: 98%

Holocene evolution of the crater lake at Malha, Northwest Sudan

et al. 1991

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A reconstruction of the hydrological and environmental evolution of the crater lake at Malha (Northern Darfur, Sudan) resulted from the mineralogical and biological study of a 9.21 m section of lake sediments, representing an uninterrupted sequence of lacustrine deposition since 8 290 14C years BP.Important changes in water supply and conditions of sedimentation are reflected in the nature of the sediments and the morphology and stratigraphical distribution of various salt minerals. Additional information on lake circulation patterns and salinity conditions are obtained from associated benthic paleocommunities, represented by ostracods and dipterid larvae. Combining both lines of evidence, the studied sequence can be divided in six distinct sections, which correspond to six successive periods in the lake's Holocene history. The first three periods, generally characterized by high lake levels, represent three generations of a meromictic lake, two of which have ended with a complete desiccation of the lake basin. Meromixis was stable during Period I, due to wind shelter and pronounced density stratification. In the course of Periods II and III stratification was repeatedly interrupted. During Period II, the disruptions were accompanied by important water budget fluctuations; a superimposed gradual decrease in net water supply eventually resulted in holomictic conditions terminating this period. Evidence of turbulence periodically affecting profundal waters is recorded in the sediments of Period III, suggesting that disruptions of stratification were now initiated by very strong winds. Between Period I and Period III, the littoral mixolimnion gradually evolved from near fresh to mesosaline. In Periods IV to VI, lake level was intermediate to low. The lake was holomictic for most of the time and meso-to hypersaline; during Period V, it repeatedly shrunk to a shallow brine pool.The Holocene evolution of Malha Crater Lake illustrates the progressive increase in aridity over most of North Africa following a well-established, early-to mid-Holocene major humid episode. The uninterrupted sedimentary sequence lends itself for detailed reconstruction of Holocene climatic evolution in arid Northeast Africa, a region where records of continuous lacustrine deposition are extremely scarce. As the chronology of critical events in the lake's history remains as yet unsupported by radiocarbon dates, correlation with other Holocene sequences in the eastern Sahara is highly tentative at this point.

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Section: Introductionmentioning

confidence: 98%

Holocene evolution of the crater lake at Malha, Northwest Sudan

et al. 1991

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Formation processes at the Ohalo II submerged prehistoric campsite, Israel, inferred from soil micromorphology and magnetic susceptibility studies

Tsatskin

Nadel

2003

Geoarchaeology

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Soil-geomorphic analysis coupled with micromorphology, SEM/EDS, magnetic susceptibility, and conventional sedimentological studies allowed us to reconstruct the site formation history and validate the archaeologically observed variability of human activities in the prehistoric camp of Ohalo II (19.5 ka B.P.), Sea of Galilee, Israel. The cultural layers rest upon the Late Pleistocene Lake Lisan deposits that accumulated under conditions of changing water supply and increasing rate of sedimentation from deep-water varvelike deposits to basaltderived, near-shore sandy lacustrine deposits. Intermittent occupation is recorded in some localities, indicating short-term inundation episodes, which led to partial truncation and deformation of the sediments, primarily in the eastern lakeward part of the site. On the elevated, landward positions, incipient soils with strongly bioturbated profiles formed. Micromorphology demonstrates that intentional flooring was applied within the remains of brush huts, where millimeter-sized, horizontally organized burnt and unheated vegetal tissues were likely to have been placed upon the compacted ground. In fireplaces, the cultural deposits in thin sections are composed of strongly mixed, abundant wood charcoal, ashes, and fishbone remains. Post-depositional alterations were controlled by intermittent inundation of the site and salinization, which induced gypsum and pyrite deposition, primarily along decayed roots, and eventual pyrite oxidation. Accumulation of sodium and chlorine in the post-occupation deposits is likely to have occurred because of discharge of saline groundwater. Although only suggestive at this stage of research, the conclusions drawn from magnetic susceptibility parameters of archaeologically related deposits at Ohalo II fit well with the micromorphological reconstructions and provide new information on the Late Pleistocene evolution of the Lake Lisan/Sea of Galilee fluctuating system. ᭧

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Salt Minerals in Saline Soils and Salt Crusts

Mees

Tursina

2018

Interpretation of Micromorphological Features of Soils and Regoliths

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Micromorphological Study of a Sediment Core from the Malha Crater Lake, Sudan

Cited by 3 publications

References 4 publications

Holocene evolution of the crater lake at Malha, Northwest Sudan

Holocene evolution of the crater lake at Malha, Northwest Sudan

Formation processes at the Ohalo II submerged prehistoric campsite, Israel, inferred from soil micromorphology and magnetic susceptibility studies

Salt Minerals in Saline Soils and Salt Crusts

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