Eolian and fluvial sedimentation in the southwestern Sinai Mountains, Egypt: a record of flash floods during the late Pleistocene

2012 ◽  
Vol 44 (2) ◽  
pp. 281-299
Author(s):  
Jörg Völkel ◽  
Jörg Grunert ◽  
Matthias Leopold ◽  
Kerstin Hürkamp ◽  
Juliane Huber ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Arid Environment ◽  
Alluvial Fan ◽  
Luminescence Dating ◽  
Alluvial Fans ◽  
Extreme Floods ◽  
Optically Stimulated Luminescence Dating ◽  
Fluvial Sedimentation ◽  
Southwestern Sinai ◽  
The Last Glacial

Wadis emerging from the southwestern Sinai Mountains (Egypt) westwards to the Gulf of Suez are filled by >40 m thick late Pleistocene sediments, which have been subsequently incised to bedrock after the Last Glacial Maximum (LGM). Sedimentation and erosion resulted from changes in the basin's hydrological conditions caused by climate variations. Sediment characteristics indicate distinct processes ranging from high to low energy flow regimes. Airborne material is important as a sediment source. The fills are associated with alluvial fans at wadi mouths at the mountain fronts. Each alluvial fan is associated and physically correlated with the respective sediment fill in its contributing wadi. The alluvial fans have steep gradients and are only a few kilometers long or wide. The alluvial fans converge as they emerge from the adjacent valleys. According to optically stimulated luminescence dating, the initial sediment has an age of ∼45 ka and the sedimentation ends ∼19 ka, i.e., happened mainly during marine isotope stage (MIS) 3 and early MIS 2 formation and initial incision sometime during LGM. As the delivery of sediments in such a hyper-arid environment is by extreme floods, this study indicates an interval of intense fluvial activity, probably related to increased frequency of extreme floods in Southern Sinai. This potentially indicates a paleoclimatic change in this hyper-arid environment.

Coupled controls of climate, geology, and biota on late Pleistocene alluvial fan morphodynamics along the coast of the hyperarid Atacama Desert

2020 ◽  
Author(s):  
Janek Walk ◽  
Melanie Bartz ◽  
Georg Stauch ◽  
Mark Reyers ◽  
Steven A. Binnie ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Atacama Desert ◽  
Source Area ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
Luminescence Dating ◽  
Alluvial Fans ◽  
Functional Relationships ◽  
Marine Terraces

<p>In the hyperarid environment of the Atacama Desert, alluvial fans are the principle fluvial geo-archive reflecting variations in climate and tectonics in their architecture. While they have been studied in the core of the desert to reconstruct long-term palaeoenvironmental changes from the Oligocene to the Quaternary and, in particular, to constrain the onset of hyperaridity, alluvial fans along the coast (20.5°S – 25.5°S) are younger and show a much higher activity; thus, they can serve as archives during the Pleistocene to Holocene evolution. However, past and recent morphodynamics of the coastal alluvial fans (CAF) are yet poorly reconstructed so that the understanding of an interplay between climatic, geologic, and biotic controls is still challenging.</p><p>We related climatic, lithologic, and tectonic source-area characteristics to geomorphometric parameters of the CAF and their catchments. Geomorphometric analyses were conducted based on the 12.5 m TanDEM‑X WorldDEM™, lithological and tectonic data were extracted from regional geological maps, and the frequency of heavy rainfall events derived from a regional Weather Research and Forecasting (WRF) model was used as a climate parameter. We further combined luminescence dating, cosmogenic nuclide exposure dating, and existing chronological data to constrain the timing of Pleistocene alluvial fan deposition as well as the ages of interbedded marine terraces.</p><p>Results indicate a primary climatic control on CAF dynamics shown in the functional relationships with catchment hydromorphometrics that mirror a high susceptibility to debris-flows as well as in the temporal pattern of CAF activity. Distinct phases of CAF activity occurred during the late Pleistocene (95–80 ka, 60–45 ka, and 35-20 ka) and the Holocene – driven by atmospheric changes from the Pacific Ocean. The primary source of precipitation is reflected along the latitudinal gradient: frontal systems and cut-off lows mainly originating from the extratropics. Towards the south, an increasing density of Loma vegetation can be observed so that also possible feedback mechanisms of biota on sediment supply need to be considered. While source-area lithology is of negligible relevance for CAF morphodynamics, an important long-term influence of tectonics can be seen in the regional uplift, which in turn controls the catchment shape and relief. From the numerical dating of the marine terraces, uplift rates ranging between ~0.06 and ~0.57 m/ka were derived for the late Pleistocene period.</p><p>Acknowledgement: TanDEM-X WorldDEM™ data is provided by a DLR Science grant, 2017.</p><p>References: <br>Bartz, M., Walk, J., Binnie, S.A., Brill, D., Stauch, G., Lehmkuhl, F., Hoffmeister, D., Brückner, H., in press. Late Pleistocene alluvial fan evolution along the coastal Atacama Desert (N Chile). Global and Planetary Change, 103091. https://doi.org/10.1016/j.gloplacha.2019.103091</p><p>Walk, J., Stauch, G., Reyers, M., Vásquez, P., Sepúlveda, F.A., Bartz, M., Hoffmeister, D., Brückner, H., Lehmkuhl, F., 2020. Gradients in climate, geology, and topography affecting coastal alluvial fan morphodynamics in hyperarid regions – The Atacama perspective. Global and Planetary Change 185, 102994. https://doi.org/10.1016/j.gloplacha.2019.102994</p>

Facies Composition and Stratigraphic Position of the Quaternary Upper Yenisei Sequence in the Tuva and Minusa Depressions

2021 ◽  
Vol 62 (10) ◽  
pp. 1127-1138
Author(s):  
I.D. Zol’nikov ◽  
I.S. Novikov ◽  
E.V. Deev ◽  
A.V. Shpansky ◽  
M.V. Mikharevich
Keyword(s):  
Late Pleistocene ◽  
Lacustrine Sediments ◽  
Alluvial Fan ◽  
Luminescence Dating ◽  
Middle Pleistocene ◽  
Mountainous Area ◽  
Gorny Altai ◽  
Stratigraphic Position ◽  
Geochronological Dating ◽  
Current Ripples

Abstract —The paper concerns the sediment sequence, which is widespread in the Yenisei valley and in the Tuva and Minusa depressions and also present in the valleys of the southern Chulym plain. The sediments of this sequence were previously described as “Neogene mud-shedding”, as well as moraines, alluvial fan deposits, alluvium of Middle Pleistocene high terraces, and lacustrine sediments. The giant ripple marks on the Upper Yenisei terraces was commonly interpreted as ribbed moraines; however, in recent studies, these ridges have been repeatedly referred to as marks of giant current ripples. Besides, some recently published papers provide description of geology of this sequence fragments suggesting its deposition by cataclysmic floods. Geomorphological analysis of the area shows Pleistocene glaciers to have been localized within the medium–high mountainous areas. The glaciers did not reach the Tuva and Minusa depressions and occupied large areas only in the Todzha basin and on the periphery of the Darkhat basin, forming a glacial dam at its outlet, which resulted in glacial-dammed lakes filling the basin completely. These lakes outburst, and the resultant flooding led to the deposition of megaflood sediments, which we refer to here as the Upper Yenisei sediment sequence. A detailed analysis of its facies architecture revealed similarity of these sediments to those of the Sal’dzhar and Inya sequences in Gorny Altai. Most of the Upper Yenisei megaflood sediments are localized in topographic lows of the Tuva and Minusa depressions. Beyond the Altai–Sayan mountainous area, the megaflood sediments of the Upper Yenisei sequence compose high terraces of the Yenisei, Chulym, Chet’, and Kiya rivers in the southern Chulym plain. The formation of Upper Yenisei sequence dates to the first half of the Late Pleistocene, inasmuch as it contains inset alluvial sediments of the second terrace of the Yenisei River. The available data allow suggesting that the Upper Yenisei sequence formed in the first Late Pleistocene regional glaciation. The Sal’dzhar sequence in Gorny Altai and the fourth terrace of the Ob’ River on the Fore-Altai plain are stratigraphic analogs of the Upper Yenisei sequence. The Upper Yenisei and Sal’dzhar sequences can thus be considered future regional markers serving as a link for the local stratigraphic schemes of the Altai–Sayan mountainous area and adjacent West Siberian plains. The results obtained call for verification by geochronological dating, first of all, by modern luminescence dating methods covering a wider chronological interval than radiocarbon dating.

scholarly journals Glacier-Induced Alluvial Fan Development on the Northeast Tibetan Plateau Since the Late Pleistocene

2021 ◽  
Vol 9 ◽  
Author(s):  
Fuyuan An ◽  
BadingQiuying ◽  
Shanlu Li ◽  
Donglin Gao ◽  
Tianyuan Chen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Pleistocene ◽  
Drainage Basin ◽  
Alluvial Fan ◽  
Alluvial Fans ◽  
Alluvial Sediments ◽  
Mis 3 ◽  
Last Glaciation ◽  
Mis 5 ◽  
Geomorphic Processes

The origin of alluvial fans at the drainage basin or the margins of the arid sedimentary basin on the northeastern Tibetan Plateau (NETP) has been a focus of debate among scientific communities. Extensive alluvial fans had developed in the mountain-basin systems of this region during the late Pleistocene. Based on geomorphic/stratigraphic studies and the optically stimulated luminescence (OSL) chronology, we investigated numerous alluvial sequences in the drainage basin of the coupled mountain-basin system on the NETP. Sedimentologic analyses showed that these alluvial sediments mainly comprise crudely meter and decimeter beds of fanglomerate and sandy lenticles, which occasionally contain boulders in the thinner layers. OSL dating results showed that the alluvial sediments were mainly developed during the late MIS 5, MIS 3, and Last Glaciation and Deglaciation (maximum aggradations), while little had occurred during the early Holocene. Comparing our ages and their probability density curves with those of glacial advances from the northeastern/eastern TP, the consistency of both records during different stages since the late Pleistocene suggested that the development of alluvial fans was driven by glacier activities, which yielded abundant outwash, feeding alluvial aggradations. Based on this finding, together with results of previous studies, we argued that the dynamics of alluvial geomorphic processes had a paleoclimatic origin rather than surface uplifts. Further studies indicated that the precipitation of glaciations originated from the ISM northward intrusion during the late MIS 5, MIS 3, and Holocene; however, it was mainly influenced by the westerlies during the Last Glaciation and Deglaciation. Therefore, the development of alluvial fans on the NETP represents coupling signals of the ISM and the westerlies on the interglacial–glacial cycle timescales. The coupling evolution of glacier activities and alluvial aggradations in the drainage basins of mountain-basin systems on the NETP provides a model for assessing the linkages between regional geomorphic processes and atmospheric circulations on hemispheric scales.

scholarly journals GEOMORPHOLOGICAL DYNAMICS OF THE ELEVATED GEOSYSTEMS OF THE BORBOREMA HIGHLANDS, NORTHEAST OF BRAZIL, FROM OPTICALLY STIMULATED LUMINESCENCE DATING OF HILLSLOPE SEDIMENTS

2020 ◽  
Vol 1 (1) ◽  
pp. 162-185
Author(s):  
ANTONIO CARLOS DE BARROS CORRÊA ◽  
KLEYTHON DE ARAUJO MONTEIRO
Keyword(s):  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Northeastern Brazil ◽  
Discrete Events ◽  
Climatic Oscillations ◽  
Optically Stimulated Luminescence Dating ◽  
Depositional Units ◽  
Sampling Procedures ◽  
The Last Glacial

The geomorphological dynamics of the elevated compartments of the Borborema Highlands, northeastern Brazil, were assessed through the analysis of hillslope sediments. The chosen study area was the Baixa Verde massif, in the State of Pernambuco. The main morphostratigraphic features were identified on the basis of their relevance to the reconstruction of the geomorphological dynamics. First hillslope deposits in the shape of colluvial fans, or infills of hollows and zero order catchments were identified. Following field study of the stratigraphic interactions in four sampling areas within the massif, samples were collected for a number of laboratory tests: sedimentological analysis, soil micromorphology and Optically Stimulated Luminescence (OSL) dating. A fragment of charcoal found on the top of a gravel layer was radiocarbon- dated. The sampling procedures were aimed at the characterization of the several depositional units. The results of the dating of 14 sampling sites point to the occurrence of discrete events of hillslope material remobilization within the last 20,000 years as a dynamic response of the geomorphological systems to the following events: the Last Glacial Maximum (LGM), the Pleistocene/Holocene transition, the mid-Holocene climatic optimum and the recent anthropic period and its short term climatic oscillations.

Single-grain OSL dating of glaciofluvial quartz constrains Reid glaciation in NW Canada to MIS 6

2012 ◽  
Vol 77 (2) ◽  
pp. 305-316 ◽  
Author(s):  
Martina Demuro ◽  
Duane G. Froese ◽  
Lee J. Arnold ◽  
Richard G. Roberts
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Palaeoenvironmental Change ◽  
Optically Stimulated Luminescence Dating ◽  
Single Grain ◽  
Cordilleran Ice Sheet ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Improved chronological control on the penultimate advance of the Cordilleran Ice Sheet in northwest Canada (the Reid glaciation) is required for a better understanding of late Quaternary palaeoclimatic and palaeoenvironmental change in eastern Beringia. However, reliable dating of glaciation events beyond the last glacial maximum is commonly hindered by a lack of directly dateable material. In this study we (i) provide the first combined minimum and maximum age constraint on the Reid glaciation at Ash Bend, its reference locale in the Stewart River valley, northwestern Canadian Cordillera, using single-grain optically stimulated luminescence dating of quartz; and (ii) compare the timing of the Reid glaciation with other penultimate ice sheet advances in the region with the aim of establishing improved glacial reconstructions in eastern Beringia. We obtain ages of 158±18 ka and 132±18 ka for glaciofluvial sands overlying and underlying the Reid till, respectively. These ages indicate that the Reid advance, at its reference locale, occurred during MIS 6. This precludes an earlier MIS 8 age, and suggests that the Reid advance may have been synchronous with the Delta glaciation of central Alaska, and is likely correlative with the Mirror Creek glaciation in southern Yukon.

scholarly journals Age of sediments on Danube terraces of the Pest Plain (Hungary) based on optically stimulated luminescence dating of quartz and feldspar

2020 ◽  
Vol 47 (1) ◽  
pp. 171-186
Author(s):  
Edit Thamó-Bozsó ◽  
Gábor Csillag ◽  
Judit Füri ◽  
Attila Nagy ◽  
Árpád Magyari
Keyword(s):  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Strong Wind ◽  
Aeolian Sediments ◽  
Optically Stimulated Luminescence Dating ◽  
Small Streams ◽  
Aeolian Activity ◽  
Wind Activity ◽  
Fluvial Sedimentation ◽  
Late Weichselian

AbstractThe numerical ages available for the sediments on the Danube terraces in the Pest Plain are scarce. In this study, we present quartz OSL and K feldspar post-IR IRSL290 ages for the sandy fluvial, aeolian and slope sediments collected from Danube terraces IIb, III and V.The feldspar post-IR IRSL290 ages without residual dose subtraction are older than the quartz OSL ages, except for one sample, but the two sets of ages are overlapping within one or two sigma errors.In the bleaching experiment under natural sunlight during summer, an unbleachable component ranging from 2.5±0.7 Gy to 5.2±0.3 Gy after 30 h exposure to bright sunshine is observed and it corresponds to 3−8% of the measured K feldspar post-IR IRSL290 equivalent doses. These facts indicate that residual dose subtraction would be necessary before age calculation, in most cases.The saturated fluvial gravelly sand of terrace V of the Danube is older than ~ 296 ka based on feldspar post-IR IRSL290 measurements. This age does not contradict the traditional terrace chronology and the earlier published age data of this terrace. The other studied sediments on the surface of the terraces V, III and IIb deposited much later than the formation of these terraces. They infer aeolian activity and fluvial sedimentation of small streams during the MIS 3 and MIS 2 periods. The age of the dated dune sands with coeval aeolian sediments in Hungary indicate the cold and dry periods with strong wind activity of the Late Weichselian.

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