Millennial to Centennial Cyclicity Within the Exoreic Saline System of Boujmel, Southern Tunisia

2022 ◽  
pp. 230-251
Author(s):  
Elhoucine Essefi
Keyword(s):  
Geological Correlation ◽  
The Holocene ◽  
Southern Tunisia ◽  
Age Model ◽  
Great Acceleration

Previous works proposed different age models of sedimentation in Sebkha Lagoon of Boujmel leading to the setting of controversial interpretations of eustatic and climatic phases. The aim of this work is carrying out a geological correlation and an astrochronological calibration based on the Holocene cyclostratigraphy leading to the setting of an age model satisfying dates of climatic and eustatic phases identified in southern Tunisia, including the Anthropocene and the Great Acceleration. Along a 130 cm core, four major climatic phases were upward recorded.

Holocene glacier fluctuations inferred from lacustrine sediment, Emerald Lake, Kenai Peninsula, Alaska

2016 ◽  
Vol 85 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Taylor S. LaBrecque ◽  
Darrell S. Kaufman
Keyword(s):  
Little Ice Age ◽  
Younger Dryas ◽  
Lacustrine Sediment ◽  
Ice Age ◽  
Sedimentary Sequence ◽  
Sharp Transition ◽  
Kenai Peninsula ◽  
The Holocene ◽  
History Of ◽  
Age Model

Physical and biological characteristics of lacustrine sediment from Emerald Lake were used to reconstruct the Holocene glacier history of Grewingk Glacier, southern Alaska. Emerald Lake is an ice-marginal threshold lake, receiving glaciofluvial sediment when Grewingk Glacier overtops the topographic divide that separates it from the lake. Sub-bottom acoustical profiles were used to locate core sites to maximize both the length and resolution of the sedimentary sequence recovered in the 4-m-long cores. The age model for the composite sequence is based on 13 14C ages and a 210Pb profile. A sharp transition from the basal inorganic mud to organic-rich mud at 11.4 ± 0.2 ka marks the initial retreat of Grewingk Glacier below the divide of Emerald Lake. The overlaying organic-rich mud is interrupted by stony mud that records a re-advance between 10.7 ± 0.2 and 9.8 ± 0.2 ka. The glacier did not spill meltwater into the lake again until the Little Ice Age, consistent with previously documented Little Ice Ages advances on the Kenai Peninsula. The retreat of Grewingk Glacier at 11.4 ka took place as temperature increased following the Younger Dryas, and the subsequent re-advance corresponds with a climate reversal beginning around 11 ka across southern Alaska.

Response of Erosion to Environmental and Climate Changes During the Anthropocene Within the Endorheic System of Mhabeul, Southeastern Tunisia

2022 ◽  
pp. 217-234
Author(s):  
Elhoucine Essefi ◽  
Soumaya Hajji
Keyword(s):  
Heavy Metals ◽  
Grain Size ◽  
Magnetic Susceptibility ◽  
Environmental Change ◽  
Clustering Techniques ◽  
The Holocene ◽  
Intrinsic Parameters ◽  
The Core ◽  
Age Model ◽  
Climatic And Environmental Change

This chapter aimed to investigate the record of climatic and environmental change in the sedimentary filling of sebkha Mhabeul and their effect on hydric and eolian erosion within the wetland and its watershed. Along a 37 cm core, the sedimentary, geochemical, and geophysical signals at the Holocene-Anthropocene transition were followed. Sampling was carried out each 1 cm to obtain 37 samples. All studied parameters and clustering techniques indicate that the first 7 cm represent the Anthropocene strata. According to the age model, this upper part of the core records the last 300 yrs. The sedimentary record of the Anthropocene is marked by an increasing rate of sedimentation, grain size fining, heavy metals (Pb, Cu, Ni, Mn, and Fe) enrichment, which is related to increased erosion. Other intrinsic parameters such as CE, pH, Na, K, and CaCO3 enhance sediment erodibility. The measurement of the magnetic susceptibility along a 37 cm core collected from the sebkha Mhabeul shows an obvious upward increase related to a high content of heavy metals for the first 7 cm.

scholarly journals A Late Glacial to Holocene record of environmental change from Lake Dojran (Macedonia, Greece)

2012 ◽  
Vol 8 (6) ◽  
pp. 5743-5785 ◽  
Author(s):  
A. Francke ◽  
B. Wagner ◽  
M. J. Leng ◽  
J. Rethemeyer
Keyword(s):  
Late Glacial ◽  
Ice Age ◽  
Humid Climate ◽  
Climate Conditions ◽  
The Holocene ◽  
Erosion Processes ◽  
Environmental Variations ◽  
Age Model ◽  
Balkan Region ◽  
Holocene Record

Abstract. A Late Glacial to Holocene sediment sequence (Co1260, 717 cm) from Lake Dojran, located at the boarder of the F.Y.R. of Macedonia and Greece, has been investigated to provide information on climate variability in the Balkan region. A robust age-model was established from 13 radiocarbon ages, and indicates that the base of the sequence was deposited at ca. 12 500 cal yr BP, when the lake-level was low. Variations in sedimentological (TOC, CaCO3, TC, N, S, grain-size, XRF, δ18Ocarb, δ13Ccarb, δ13Corg) data were linked to hydro-acoustic data and indicate that warmer and more humid climate conditions characterized the remaining period of the Younger Dryas until the beginning of the Holocene. The Holocene exhibits significant environmental variations, including the 8.2 ka and 4.2 ka cooling events, the Medieval Warm Period, and the Little Ice Age. Human induced erosion processes in the catchment of Lake Dojran intensified after 2800 cal yr BP.

scholarly journals A Late Glacial to Holocene record of environmental change from Lake Dojran (Macedonia, Greece)

2013 ◽  
Vol 9 (1) ◽  
pp. 481-498 ◽  
Author(s):  
A. Francke ◽  
B. Wagner ◽  
M. J. Leng ◽  
J. Rethemeyer
Keyword(s):  
Late Glacial ◽  
Ice Age ◽  
Humid Climate ◽  
Climate Conditions ◽  
The Holocene ◽  
Erosion Processes ◽  
Environmental Variations ◽  
Age Model ◽  
Balkan Region ◽  
Holocene Record

Abstract. A Late Glacial to Holocene sediment sequence (Co1260, 717 cm) from Lake Dojran, located at the boarder of the F.Y.R. of Macedonia and Greece, has been investigated to provide information on climate variability in the Balkan region. A robust age-model was established from 13 radiocarbon ages, and indicates that the base of the sequence was deposited at ca. 12 500 cal yr BP, when the lake-level was low. Variations in sedimentological (H2O, TOC, CaCO3, TS, TOC/TN, TOC/TS, grain-size, XRF, δ18Ocarb, δ13Ccarb, δ13Corg) data were linked to hydro-acoustic data and indicate that warmer and more humid climate conditions characterised the remaining period of the Younger Dryas until the beginning of the Holocene. The Holocene exhibits significant environmental variations, including the 8.2 and 4.2 ka cooling events, the Medieval Warm Period and the Little Ice Age. Human induced erosion processes in the catchment of Lake Dojran intensified after 2800 cal yr BP.

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