Variability to sedimentary dynamics and climatic conditions during the last two millennia at sebkha Souassi in eastern Tunisia

AbstractThis paper covers work intended to study the interplay of sedimentary dynamics and climatic variability over the last two millennia within Tunisia’s sebkha Souassi. Based on the Visual Core Description, and magnetic susceptibility, we date the core from sebkha Souassi to the last two millennia. Genetic grain-size distribution then provided a basis for the identification of six climatic stages, i.e. the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Ages (DA), and the Roman Warm Period (RWP). The WP stretches across the uppermost 3 cm, with a high grey scale indicating a dry climate. The Late LIA is located between 3 and 7 cm, and the ELIA between 7 and 28 cm. Intermediate values for GS indicate that this stage may be classified as moderate. The MCA spanning from 28 to 40 cm is marked by a sharp decrease in GS indicative of a wet period. The DA appear along the part between 40 and 79 cm, a shift from light to dark sediments being recorded. The RWP in turn appears between 79 and 114 cm. Based on the grain-size distribution, two low-frequency cycles were identified, indicating radical global changes in climatic conditions, differential tectonics and groundwater fluctuations. High-frequency cycles in turn attest to local modifications of climatic conditions.

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Record of the Climatic Variability and the Sedimentary Dynamics during the Last Two Millennia at Sebkha Dkhila, Eastern Tunisia

ISRN Geology ◽

10.1155/2013/936198 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Elhoucine Essefi ◽

Jamel Touir ◽

Mohamed Ali Tagorti ◽

Chokri Yaich

Keyword(s):

Little Ice Age ◽

Climatic Variability ◽

Low Frequency ◽

Climatic Conditions ◽

Ice Age ◽

Global Changes ◽

Medieval Climatic Anomaly ◽

Grey Scale ◽

Sedimentary Dynamics ◽

The Last Two Millennia

This paper aimed to study the record of the climatic variability during the last two millennia within the sebkha of Dkhila. Six climatic stages were recognized along the 104 cm core: the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Age (DA), and the Roman Warm Period (RWP). The WP stretches along the uppermost 1 cm with a high grey scale as sign of a dry climate. The Late LIA is located between 1 cm and 6 cm. The ELIA is located between 6 cm and 40 cm. The MCA spanning from 40 cm to 72 cm is marked by a sharp increase of the GS revealing a wet period. The DA appears along the part between 72 cm and 84 cm; a shift from light to dark sediments is recorded. The RWP appears between 84 cm and 104 cm. Based on the grain size distribution, two low frequency cycles were identified indicating radical global changes of climatic conditions, the differential tectonics, and the groundwater fluctuations. On the other hand, high frequency cycles indicate local modifications of the climatic conditions.

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Sedimentary Dynamics Within the Sedimentary Filling of Sebkha Sidi El Hani, Eastern Tunisia

10.4018/978-1-7998-8459-0.ch012 ◽

2022 ◽

pp. 235-259

Author(s):

Elhoucine Essefi ◽

Soumaya Hajji ◽

Mohamed Ali Tagorti

Keyword(s):

Little Ice Age ◽

Climatic Variability ◽

Ice Age ◽

Genetic Approach ◽

Grey Scale ◽

Stable Conditions ◽

Salt Crust ◽

Sedimentary Dynamics ◽

Core Description ◽

The Last Two Millennia

The Sidi El Hani Wetland is located in Eastern Tunisia. It represents the natural outlet of an endorheic system, Mechertate-Chrita-Sidi El Hani, and it collects all the eroded sediment from this watershed. In this chapter, the visual core description focused on three reference sandy bands and on the concept of grey scale variability in order to infer the clay pan response to the climatic variability and erosion during the last two millennia. First, in the uppermost part, the stage Warming Present (WP) stretches from (1954-80= 1874) to 1993, i.e. ≈120yrs; the establishment of modern conditions is characterized by stable conditions with high grey scale. Added to a small salt crust, this period is dominated by a clayey sedimentation. Second, the stage C4 is called the Late Little Ice Age (Late LIA); it stretches between the 80yrBP and 400yrBP, i.e., 320yrs. It is characterized by intermediate GS values; the clayey sedimentation makes up the twofold and threefold laminates. Based on laser granulometer, the genetic approach shows the interplay of eolian and hydraulic erosion.

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Reconstructing 1200 years of hydroclimate variability in the southern margins of the Arabian Desert, inferred from an ancient lake in southern Yemen

10.5194/egusphere-egu21-14756 ◽

2021 ◽

Author(s):

Shah Parth ◽

James M Russell ◽

Nicolas Waldmann

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Little Ice Age ◽

Ice Age ◽

Boreal Summer ◽

The Core ◽

The Past ◽

Monsoon Variability ◽

Warming World

There is a major knowledge gap in the past climate oscillation of the Arabian desert, especially during the past two millennium. Reliable continuous continental records that archives at high resolution past environmental variability are useful sentinels of paleoclimate changes. Reliable interpretation from climatic proxies retrieved from lake records are crucial for identifying periodicities and the onset of climatic events and evaluating inter-annual and decadal trends driven by shifting of the Intertropical Convergence Zone (ITCZ). A multiproxy approach is presented for a ~3.3 m composite core from a karst lake located in Gayal el Bazal, southern Yemen. Sedimentary proxies, including grain size distribution and magnetic susceptibility (MS) coupled with geochemistry (XRF), provide an initial picture of centennial-scale environmental changes over the southern Arabian desert. The chronology of the core was anchored by five radiocarbon (14C) dates of terrestrial plants (wood) extracted from sediment samples and indicates the core extends to ~800 AD. Our data provides a snapshot for better understanding the impact of Indian Ocean monsoon variability at an exceptional resolution for a region that lacks sufficient information. Our data indicates that during the &#8216;Little Ice Age&#8217; (~1500-1800 AD) was arid relative to the warm conditions that prevailed during the Medieval Warming Period (~800 to 1200 AD). The arid phase was marked by high Ca/(Al, Fe, Ti) values, increased inorganic carbon content, decreased MS values, and gypsum precipitation. Furthermore, end-member mixing analyses (EMMA) derived from the grain-size distribution corroborates the production of carbonate sand probably due to an increase in flash floods occurring concurrently with low lake levels under generally dry conditions. Aridity during the Little Ice Age is consistent with evidence and theory for weakened boreal summer monsoons during intervals of northern hemisphere cooling. Overall, this study will provide insight into the monsoon variability and a record for understanding the interactions between northward migrations of the ITCZ and tropical monsoonal dynamics during the late Holocene. In the context of current climate change and increasing population pressure, a deeper understanding of their long-term hydrological variability, this study is highly essential to satisfactorily forecast the sustainability of lakes as a resource in a warming world.

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New insights on sediment provenance in the Dead Sea since the last glacial maximum using grain-size distribution

10.5194/egusphere-egu2020-20276 ◽

2020 ◽

Author(s):

Cecile Blanchet ◽

Hana Jurikova ◽

Julia Fusco ◽

Rik Tjallingii ◽

Markus Schwab ◽

...

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Lake Level ◽

Regional Climate ◽

Dead Sea ◽

Sediment Provenance ◽

Last Deglaciation ◽

Sedimentary Dynamics ◽

The Dead

Sedimentary records from the Dead Sea constitute unique paleoclimatic archives that enable investigating the response of environments to climatic changes. Large lake-level fluctuations (>100 m) occurred during the past glacial-interglacial cycles due to reorganizations of the hydroclimatic regime and drastically modified the morphology of the drainage area. We aim here to reconstruct past sedimentary dynamics at times of varying lake level to gain insights into paleoclimate and landscape evolution.For this study, we have compared present-day surface sediments (fluvial and soil sediments) retrieved on both the eastern Jordanian and western shores of the present Dead Sea with downcore sediment archives including the ICDP Dead Sea Deep Drilling Program Site 5017-1. Streams originating from various parts of the watershed can be distinguished by their grain-size distribution, with northern and south-western streams having generally finer grain-size modes when compared with streams from the eastern side. We find that all modes identified in the fluvial sediments were present in the ICDP downcore samples from the last deglaciation, when lake levels were up to 250m higher than today. This suggests that the whole watershed contributed to the sediment input at that time. In contrast, Holocene sediments from the deep core and shore deposits are enriched in fluvial particles showing similar grain-size modes as the northern and south-western streams. This suggests that these regions were prime sediment sources during lower lake-level stands. An additional mode, tentatively related to aeolian particles, was also identified in the Holocene samples, pointing to the remobilization of deposited dust in the watershed or to a more arid regional climate.Our results provide a first synoptic view on sedimentary dynamics in the Dead Sea watershed and help to relate sediment provenance to the drainage morphology and paleo-hydrological regimes. They constitute a solid basis for further assessment of sedimentary provenance using geochemical indicators.

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Variation of the Descriptive Grain Size Distribution Along Cores From the Sebkha of Sidi El Hani, Eastern Tunisia

10.4018/978-1-7998-9498-8.ch012 ◽

2022 ◽

pp. 197-214

Author(s):

Elhoucine Essefi ◽

Soumaya Hajji

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Method Of Moments ◽

Statistical Treatment ◽

Special Care ◽

Statistical Parameters ◽

Sedimentary Dynamics

In this chapter, cores were the object of descriptive classifications of the grain size distribution, which were meant to describe the grain size continuous variability within cores and to correlate between them. The statistical treatment of the crude data was done on the basis of two different methods (the method of moments statistics and the method of inclusive graphic statistics) to compute statistical parameters of the grain size distribution such as mean and median. The correlations between cores were done on the basis of sand/silt/clay percentages. Even though it has given special care to test different methods of studying the grain size distribution, this study has not deviated from its primary purpose of investigating the filling of the playa; correlations between different cores were meant to infer their sedimentary dynamics.

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Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway

Solid Earth ◽

10.5194/se-5-485-2014 ◽

2014 ◽

Vol 5 (1) ◽

pp. 485-498 ◽

Cited By ~ 7

Author(s):

A. Navas ◽

K. Laute ◽

A. A. Beylich ◽

L. Gaspar

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Soil Profile ◽

Mineralogical Composition ◽

Ice Age ◽

Drainage Basins ◽

Western Norway ◽

Ice Retreat ◽

Profile Characteristics

Abstract. In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils were formed after deglaciation. The climate in the uppermost valley areas is sub-arctic oceanic, and the lithology consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. The Little Ice Age glacier advance affected parts of the valleys with the maximum glacier extent around AD 1750. In this study five sites on moraine and colluvium materials were selected to examine main soil properties, grain size distribution, soil organic carbon and pH to assess if soil profile characteristics and patterns of fallout radionuclides (FRNs) and environmental radionuclides (ERNs) are affected by different stages of ice retreat. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. The sampled soils on the colluviums outside the LIA glacier limit became ice-free during the Preboral. The Regosols present better-developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137Cs and 210Pbex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Significantly lower mass activities of FRNs were found in soils on the moraines than on colluviums. Variations of ERN activities in the valleys were related to characteristics of soil mineralogical composition. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137Cs and 210Pbex activities differs in the soils related to the LIA glacier limits in the drainage basins.

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Record of the Sedimentary Dynamics and Climatic Variability Within the Sedimentary Filling of Mchiguig Wetland During the Late Holocene

10.4018/978-1-7998-9498-8.ch015 ◽

2022 ◽

pp. 252-266

Author(s):

Elhoucine Essefi

Keyword(s):

Solar Activity ◽

Little Ice Age ◽

Climatic Variability ◽

Ice Age ◽

Medieval Climatic Anomaly ◽

Climatic Anomaly ◽

Sedimentary Dynamics ◽

Atmospheric Factors ◽

Sun Activity ◽

Great Acceleration

This work aimed to study the cyclicity of the geochemical chemical parameters and the carbonate percentages along a 59 cm core from the sebkha of Mchiguig, Central Tunisia. In fact, from the bottom upwards, six climatic phases were recorded including the Warming Present (Great Acceleration), the Late Little Ice Age (Anthropocene), the Early Little Ice Age, the Medieval Climatic Anomaly, the Dark Age, and the Roman Warm Period. In fact, the spectral analysis of the studied parameters visualized many cycles. Those cycles are related to sun activity, oceanographic, and atmospheric factors. Solar activity generated 500 yr cycles; however, the oceanographic circulation generated other cycles of 1500 yr and 700-800 yr. The 1500 yr cycle may be the result of the solar activity and NAO-like circulation.

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Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway

Solid Earth Discussions ◽

10.5194/sed-6-91-2014 ◽

2014 ◽

Vol 6 (1) ◽

pp. 91-118

Author(s):

A. Navas ◽

K. Laute ◽

A. A. Beylich ◽

L. Gaspar

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Soil Profile ◽

Mineralogical Composition ◽

Ice Age ◽

Drainage Basins ◽

Western Norway ◽

Ice Retreat ◽

Profile Characteristics

Abstract. In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils have been formed after deglaciation. The climate in the uppermost valley areas is sub-arctic oceanic and the lithology consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. The Little Ice Age glacier advance affected parts of the valleys with the maximum glacier extent around AD 1750. In this study five sites on moraine and colluvium materials were selected to examine the main soil properties to assess if soil profile characteristics and pattern of fallout radionuclides (FRNs) and environmental radionuclides (ERNs) are affected by different stages of ice retreat. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. The sampled soils on the colluviums outside the LIA glacier limit became ice-free during the Preboral. The Regosols present better-developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137Cs and 210Pbex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Significant lower mass activities of FRNs are found in soils on the moraines than on colluviums. Variations of ERNs activities in the valleys are related to characteristics soil mineralogical composition. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137Cs and 210Pbex activities differs in the soils related to the LIA glacier limits in the drainage basins.

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