scholarly journals A Late Pleistocene Wetland Setting in the Arid Jurf ed Darawish Region in Central Jordan

2021 ◽  
Vol 9 ◽  
Author(s):  
Steffen Mischke ◽  
Zhongping Lai ◽  
Galina Faershtein ◽  
Naomi Porat ◽  
Matthias Röhl ◽  
...  
Keyword(s):  
Regional Climate ◽  
Subsurface Water ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Southern Levant ◽  
Fine Grained ◽  
Vertical Range ◽  
Central Jordan ◽  
Loess Deposits ◽  
Mis 5

Current conditions in the southern Levant are hyperarid, and local communities rely on fossil subsurface water resources. The timing of more favourable wetter periods and also their spatial characteristics are not yet well constrained. To improve our understanding of past climate and environmental conditions in the deserts of the southern Levant, sedimentary sections including artefact-bearing beds from Jurf ed Darawish on the Central Jordanian Plateau were investigated using sedimentological and micropalaeontological analyses and OSL dating. Grain-size analysis and structures of the clayey-silty sediments show that they mainly represent reworked loess deposits. The OSL ages suggest that these fine-grained sediments were accumulated during Marine Isotope Stages (MIS) 5-3. Recorded ostracod valves (mostly Potamocypris, Ilyocypris and Pseudocandona), remains of aquatic and terrestrial gastropod shells, and charophyte gyrogonites and stem encrustations indicate that an in-stream wetland existed at the location of Jurf ed Darawish during MIS 5-4 which was replaced by a vegetated alluvial plain in MIS 3. The prevailing aggradational setting was replaced by an erosional setting sometime after 30 ka. Abundant artefacts, distributed over a vertical range of up to 40 cm in a bed covered by a sedimentary sequence of 12-m thickness, provide evidence for the presence of humans in the region during a relatively long period from ca. 85 to 65 ka. The reconstruction of an in-stream wetland at Jurf ed Darawish, and the presence of humans at the site and in other desert regions of the Jordanian Plateau, the Wadi Arava/Araba, and the Negev and the Nefud deserts, show that the regional climate in the late MIS 5 and MIS 4 was significantly wetter than today and provided favourable conditions for humans in the Southern Levant and the northwestern Arabian Peninsula.

scholarly journals Grain size statistics and depositional pattern of the Ecca Group sandstones, Karoo Supergroup in the Eastern Cape Province, South Africa

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Christopher Baiyegunhi ◽  
Kuiwu Liu ◽  
Oswald Gwavava
Keyword(s):  
South Africa ◽  
Grain Size ◽  
Depositional Environments ◽  
Energy Conditions ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Equal Proportion ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Fine Grained

AbstractGrain size analysis is a vital sedimentological tool used to unravel the hydrodynamic conditions, mode of transportation and deposition of detrital sediments. In this study, detailed grain-size analysis was carried out on thirty-five sandstone samples from the Ecca Group in the Eastern Cape Province of South Africa. Grain-size statistical parameters, bivariate analysis, linear discriminate functions, Passega diagrams and log-probability curves were used to reveal the depositional processes, sedimentation mechanisms, hydrodynamic energy conditions and to discriminate different depositional environments. The grain-size parameters show that most of the sandstones are very fine to fine grained, moderately well sorted, mostly near-symmetrical and mesokurtic in nature. The abundance of very fine to fine grained sandstones indicate the dominance of low energy environment. The bivariate plots show that the samples are mostly grouped, except for the Prince Albert samples that show scattered trend, which is due to the either mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under shallow marine environments for samples from the Prince Albert, Collingham and Ripon Formations, while those samples from the Fort Brown Formation are lacustrine or deltaic deposits. The C-M plots indicated that the sediments were deposited mainly by suspension and saltation, and graded suspension. Visher diagrams show that saltation is the major process of transportation, followed by suspension.

scholarly journals Investigation of Particle Size Distribution for Fine-Grained Soil Using a Grain Size Analysis Equipment Automated by X-ray Method

2000 ◽  
Vol 40 (2) ◽  
pp. 127-133
Author(s):  
Yukio Furukawa ◽  
Tatsushi Fujita ◽  
Tadayuki Kunihiro ◽  
Hisashi Tsuchiya ◽  
Yukio Saito
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Ray Method ◽  
X Ray ◽  
Fine Grained ◽  
Fine Grained Soil

Nahan Sandstone and its exfoliation, Nainital District, Uttar Pradesh, India

1971 ◽  
Vol 108 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Brijraj K. Das ◽  
Vanshnarayan
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Uttar Pradesh ◽  
Igneous Rocks ◽  
Granitic Rocks ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Physical Processes ◽  
Fine Grained ◽  
Petrographic Study

SummaryThe Nahan sandstone of the Nainital district is a soft, fine-grained sandstone of subgreywacke type. Like massive igneous rocks it is very well exfoliated and consists of many concentric layers. Petrographic study of different layers of this sandstone, modal analysis, grain size analysis, and size distribution of the various samples, have revealed that physical processes are mainly responsible for exfoliation of the sandstone. The study of various sedimentary parameters indicated that the provenance is from the schistose and granitic rocks of the surrounding Himalayan mountains and the material was deposited in a shallow slowly sinking basin.

scholarly journals Textural characteristics, mode of transportation and depositional environment of the Cretaceous sandstone in the Bredasdorp Basin, off the south coast of South Africa: Evidence from grain size analysis

2020 ◽  
Vol 12 (1) ◽  
pp. 1512-1532
Author(s):  
Temitope Love Baiyegunhi ◽  
Kuiwu Liu ◽  
Oswald Gwavava ◽  
Christopher Baiyegunhi
Keyword(s):  
Grain Size ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Statistical Parameters ◽  
Shallow Marine ◽  
Fine Grained ◽  
Textural Parameters ◽  
Mode Of Transportation ◽  
Relationship Of

AbstractA total of 92 representative sandstone samples of the Bredasdorp Basin in boreholes E-AH1, E-AJ1, E-BA1, E-BB1 and E-D3 have been investigated for their grain size characteristics. Grain size textural parameters and their cross plots, linear discriminate functions (LDFs), C–M (C = first percentile and M = median) diagram and log–probability plots were calculated and interpreted to understand the mode of transportation and hydrodynamic conditions and also to unravel the depositional environments of the sediments. The grain size textural parameters revealed that the Bredasdorp sandstones are unimodal, predominantly fine-grained, moderately well-sorted, mesokurtic and near symmetrical. The bivariate plots of grain size textural parameters indicate that the depositional environments had been influenced mainly by river/beach/coastal dune conditions. The LDF plots show that the sediments are turbidity current deposits in a shallow marine environment. The C–M diagram revealed that the studied sandstones were mainly deposited by traction currents and beach process. In addition, the grain size log–probability curves and C–M diagram show the predominance of suspension and saltation modes of sediment transportation. Based on the inter-relationship of the various statistical parameters, it is deduced that the Bredasdorp Basin are mainly shallow marine deposits with signature of beach and coastal river processes.

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