scholarly journals Dust-storm Events in Daihai Lake Area, Inner Mongolia During the Past 400 Years Evidence from Grain-size Analysis of Lake Sediments

2000 ◽  
Vol 12 (3) ◽  
pp. 193-198 ◽  
Author(s):  
JIN Zhangdong ◽  
◽  
WANG Sumin ◽  
SHEN Ji ◽  
ZHANG Enlou ◽  
...  



2020 ◽  
Vol 103-104 (5-6) ◽  
pp. 50-56
Author(s):  
Yuliia Avdieienko

New approaches developed within the complex palaeogeographic methodology of cave deposits studies for reconstruction of the past ecological conditions are presented in the paper. The relevance and reliability of results of such studies are shown on the cases from the previous research of cave systems in Ukraine. The methodology based of palynological and lithological (including grain-size analysis) study of terrigenous cave deposits is proposed, and the advantages of their complex application within the multidisciplinary palaeoenvironmental study are proved. The reliability of palaeovegetational reconstructions based on pollen studies of clastic cave deposits is confirmed by the compatibility of their results with those obtained from coeval subaerial deposits. The same patterns were shown by a comparison of pollen from hyaena coprolites in the cave and their enclosing sediments. It has been found that the content of redeposited pollen in the clastic sediments of caves depends on their particle size distribution, sharply increasing in sandy deposits. The grain-size composition of cave deposits also provides information on the genesis of deposits and, thus, indirectly, on paleoenvironmental conditions. Changes in clay, large silt and sand fractions are of main importance for the interpretation of the results. A direct correlation of paleoclimatic signals obtained by the results of pollen and lithological analyses with the indicators of magnetic susceptibility has been established. The use of these paleogeographic methods for studying cave deposits, namely pollen analyses, lithological (in particular, grain-size), palaeontological, petromagnetic, palaeogenetic, radiocarbon and paleomagnetic methods, will be able to control the reliability of the reconstruction by collate them. Multidisciplinary study of the cave deposits has a great potential for reconstructions of the ancient Man environments as deposits of many caves include archaeological horizons of different material cultures from the Early Palaeolithic to the Early Iron Age.



Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 106 ◽  
Author(s):  
Marcin Hojan ◽  
Mirosław Rurek ◽  
Mirosław Więcław ◽  
Adam Krupa

The article aims to present extreme aeolian processes observed in April 2011 in the fields of the Szamocin municipality in Pojezierze Wielkopolskie (the Great Poland Lakeland). Aeolian erosion of cropland was fostered by strong wind with gusts exceeding 15 m·s−1. The erosion was related to the movement of a deep barometric low from the Norwegian Sea over western Russia (Joachim barometric low). Geomorphological mapping of accumulated sandy aeolian covers was conducted. Morphometric measurements of aeolian covers were made considering their spatial distribution and the thickness of sediments that build them. Samples were collected from sediments to analyze grain size and the volume of deposited sediments was calculated. According to grain size analysis the accumulated fine-grained mineral material was well, moderately well and moderately sorted. The thickness of aeolian covers exceeded the thickness of covers presented in Polish literature so far. Calculations of the total volume of mineral sediment derived from small areas covered with aeolian erosion (a few hectares each) indicate significantly greater volumes than those provided in publications from other research areas in Poland. The described dust storms did not cause much damage in Poland. At the same time (8 April) in northern Germany, a dust storm led to a severe collision on the A19 highway. Eight people died in car accidents and dozens suffered serious injuries.





Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Srećko Bevandić ◽  
Rosie Blannin ◽  
Jacqueline Vander Auwera ◽  
Nicolas Delmelle ◽  
David Caterina ◽  
...  

Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics of the different mine waste materials found at the site. Four types of material were classified: soil, metallurgical waste, brown tailings and yellow tailings. The distribution of the mine wastes was investigated with drill holes, pit-holes and geophysical methods. Samples of the materials were assessed with grain size analysis, and mineralogical and geochemical techniques. The mine wastes dominantly consist of SiO2, Al2O3 and Fe2O3. The cover material, comprising soil and metallurgical waste is highly heterogeneous in terms of mineralogy, geochemistry and grain size. The metallurgical waste has a high concentration of metals (Zn: 0.1 to 24 wt.% and Pb: 0.1 to 10.1 wt.%). In the tailings materials, Pb and Zn vary from 10 ppm to 8.5 wt.% and from 51 ppm to 4 wt.%, respectively. The mining wastes comprises mainly quartz, amorphous phases and phyllosilicates, with minor contents of Fe-oxide and Pb- and Zn-bearing minerals. Based on the mineralogical and geochemical properties, the different potential applications of the four waste material types were determined. Additionally, the theoretical economic potential of Pb and Zn in the mine wastes was estimated.



2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.



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