Post-IR IRSL chronology of paleo-lacustrine sediments from yardangs in the Qaidam Basin, ne Tibetan Plateau

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhaojing Ding ◽  
Lupeng Yu ◽  
Zhongping Lai ◽  
Ping An ◽  
Xiaodong Miao ◽  
...  
Keyword(s):  
Wind Erosion ◽  
Qaidam Basin ◽  
Lacustrine Sediments ◽  
Climatic Changes ◽  
Google Earth ◽  
Marine Isotopic Stage ◽  
Erosion Processes ◽  
Dating Methods ◽  
Erosion Environment ◽  
Geomorphic Processes

Abstract The Qaidam Basin preserves the largest Yardang field on Earth, and yardangs are intriguing landforms for studies of the paleo-environment and aeolian processes. Formation of yardangs involved both the initial lacustrine deposition and the subsequent wind-erosion processes. However, the timings of both processes in the Qaidam Basin are still controversial due to limited age data and unsuitable dating methodology. In this paper, we first compared two optical dating methods to determine the suitable one for the study area, then investigated the geomorphic processes based on the new ages. Two-step post-IR IRSL (pIRIR) and multi-elevated-temperature pIRIR (MET-pIRIR) methods of feldspar, were applied to date lacustrine sediments on the top parts of yardangs to decipher the transition time from depositional to an erosional environment. Comparisons of the two methods demonstrated that the influence from anomalous fading was very minimal thus negligible for MET-pIRIR method, as proved by the De plateau between MET-pIRIR250 and MET-pIRIR290; while the pIR50IR250 signals suffered from fading obviously, which was difficult to be corrected due to the high De close to saturation. Consequently, the chronology in this study was based on the MET-pIRIR250 method, potentially offering reliable ages of over 200 ka. Seven MET-pIRIR250 ages of 201–336 ka suggested that a mega-Qaidam Lake (>2714 m a.s.l. on Google Earth) maintained until Marine Isotopic Stage (MIS) 7. The absence of sediments since ca. 200 ka implied wind-erosion and yardang formation since MIS6. This transition from lacustrine to a wind-erosion environment was interpreted as a response to the glacial-interglacial scale climatic changes.

scholarly journals Automated Characterization of Yardangs Using Deep Convolutional Neural Networks

2021 ◽  
Vol 13 (4) ◽  
pp. 733
Author(s):  
Bowen Gao ◽  
Ninghua Chen ◽  
Thomas Blaschke ◽  
Chase Q. Wu ◽  
Jianyu Chen ◽  
...  
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Qaidam Basin ◽  
Regional Distribution ◽  
Lacustrine Sediments ◽  
Morphological Characteristics ◽  
Representation Learning ◽  
Google Earth ◽  
Detection Accuracy ◽  
Deep Convolutional Neural Networks

The morphological characteristics of yardangs are the direct evidence that reveals the wind and fluvial erosion for lacustrine sediments in arid areas. These features can be critical indicators in reconstructing local wind directions and environment conditions. Thus, the fast and accurate extraction of yardangs is key to studying their regional distribution and evolution process. However, the existing automated methods to characterize yardangs are of limited generalization that may only be feasible for specific types of yardangs in certain areas. Deep learning methods, which are superior in representation learning, provide potential solutions for mapping yardangs with complex and variable features. In this study, we apply Mask region-based convolutional neural networks (Mask R-CNN) to automatically delineate and classify yardangs using very high spatial resolution images from Google Earth. The yardang field in the Qaidam Basin, northwestern China is selected to conduct the experiments and the method yields mean average precisions of 0.869 and 0.671 for intersection of union (IoU) thresholds of 0.5 and 0.75, respectively. The manual validation results on images of additional study sites show an overall detection accuracy of 74%, while more than 90% of the detected yardangs can be correctly classified and delineated. We then conclude that Mask R-CNN is a robust model to characterize multi-scale yardangs of various types and allows for the research of the morphological and evolutionary aspects of aeolian landform.

OSL chronology for lacustrine sediments recording high stands of Gahai Lake in Qaidam Basin, northeastern Qinghai–Tibetan Plateau

2010 ◽  
Vol 5 (2-3) ◽  
pp. 223-227 ◽  
Author(s):  
QiShun Fan ◽  
ZhongPing Lai ◽  
Hao Long ◽  
YongJuan Sun ◽  
XiangJun Liu
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Lacustrine Sediments

scholarly journals Voloshchuk M. D., Petrenko N. I., Yatsenko S. V. Erosian of soils of Ukraine: the evolution of theory and practice. – Kyiv : Nilan, Ltd., 2014. – 325 p.

2015 ◽  
Vol 16 (1-2) ◽  
pp. 102-106
Author(s):  
A. P. Travleyev ◽  
V. A. Gorban
Keyword(s):  
Soil Erosion ◽  
Wind Erosion ◽  
Academic Staff ◽  
Arable Land ◽  
Great Part ◽  
Theory And Practice ◽  
Forest Steppe ◽  
National Academy Of Sciences ◽  
Erosion Processes ◽  
National University

At the present time the great part of soils is exposed to various negative processes. One of the basic processes that lead to the degradation of soils in Ukraine is the erosion. According to the recent data, water and wind erosion covers 13.9 million hectares; it is about 33 % of the total arable land in the country. On this basis, the greater relevance belongs to the scientific studies displaying the features of negative phenomena of our soil, and, most importantly, the ways of solving of these urgent problems on the soil cover of Ukraine. The monograph «Soil erosion in Ukraine: the evolution of theory and practice» of such famous scientists in the field of Soil Erosion Science as Voloshchuk M. D., Petrenko N. I. and Yatsenko S. V. is one of such fundamental works. In the present monograph, considerable attention is paid to the periodization of the formation and development of the doctrine of soil erosion in Ukraine. The authors identify six basic stages of formation of the national Soil Erosion Science. The paper discusses the characteristic features of isolation of Soil Erosion Science as an independent scientific direction and a self-discipline, which are based on the works of such renowned scientists as P. S. Tregubov, M. N. Zaslavsky and G. I. Shvebs. A significant place in the monograph is devoted to the characteristics of the scientific centers of Ukraine, in which the Soil Erosion Science has been developed. These centers are distinguished by leading scientists, under the leadership of whom, the erosion processes have been studied. The authors of the monograph provides four main scientific centers of the country in the field of Soil Erosion Science development: National Scientific Centre «Institute of Agriculture of the National Academy of Agricultural Sciences» (central region), National Scientific Center «Institute for Soil Science and Agrochemistry Research named after O. N. Sokolovsky», Scientific-Technical Center «Fertility» (Kharkiv region), Odessa I. I. Mechnikov National University (south region), Lviv National Agrarian University, Institute of Ecology of the Carpathians of National Academy of Sciences of Ukraine, Ivan Franko National University of Lviv and others (west region). In addition to considering the features of the listed centers, in the work there is a presentation of a brief description of the project, research institutes, agricultural and agroforestry research stations that are active in a scientific work in relation to soil erosion processes. In the work, there are also the historical aspects and mechanisms for the further development of wind erosion researches. Considerable attention the authors of the monograph pay to the analysis of the current state, challenges and prospects of solving the problem on protecting the soil from erosion. The main problem of the country's soil, which is the cause of widespread erosion, is a very high agricultural development of the territory, more than half of which falls onto an arable land. At the end of the monograph, there are a large number of photos, provided by Professor M. D. Voloshchuk, which recorded various aspects of soil erosion manifestations, as well as the ways of its overcoming in the conditions of forest-steppe and steppe zones in Ukraine and on the territory of Moldova. The reviewed monograph is certainly a very relevant and timely generalizing scientific research that will be useful in the theoretical and practical use of students, academic staff of the natural and agricultural higher education institutions, research organizations.

Clay minerals and isotopes of Pleistocene lacustrine sediments from the western Qaidam Basin, NE Tibetan Plateau

2018 ◽  
Vol 162 ◽  
pp. 382-390 ◽  
Author(s):  
Minghui Li ◽  
Shurui Sun ◽  
Xiaomin Fang ◽  
Chunhong Wang ◽  
Zhengrong Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Clay Minerals ◽  
Qaidam Basin ◽  
Lacustrine Sediments ◽  
Western Qaidam Basin ◽  
Ne Tibetan Plateau

Changes in wind erosion climatic erosivity in northern China from 1981-2016: a comparison of two climate/weather factors of wind erosion models

2021 ◽  
Vol 83 ◽  
pp. 133-146
Author(s):  
F Zhang ◽  
J Wang ◽  
X Zou ◽  
R Mao ◽  
DY Gong ◽  
...  
Keyword(s):  
Wind Erosion ◽  
Qaidam Basin ◽  
Dust Emission ◽  
Northern China ◽  
Northwest China ◽  
Gobi Desert ◽  
Weather Factors ◽  
Weather Factor ◽  
Increasing Trend ◽  
Erosion Equation

Wind erosion is largely determined by wind erosion climatic erosivity. In this study, we examined changes in wind erosion climatic erosivity during 4 seasons across northern China from 1981-2016 using 2 models: the wind erosion climatic erosivity of the Wind Erosion Equation (WEQ) model and the weather factor from the Revised Wind Erosion Equation (RWEQ) model. Results showed that wind erosion climatic erosivity derived from the 2 models was highest in spring and lowest in winter with high values over the Kumtag Desert, the Qaidam Basin, the boundary between Mongolia and China, and the Hulunbuir Sandy Land. In spring and summer, wind erosion climatic erosivity showed decreasing trends in whole of northern China from 1981-2016, whereas there was an increasing trend in wind erosion climatic erosivity over the Gobi Desert from 1992-2011. For the weather factor of the RWEQ model, the difference between northern Northwest China and the Gobi Desert and eastern-northern China was much larger than that of the wind erosion climatic erosivity of the WEQ model. In addition, in contrast to a decreasing trend in the weather factor of the RWEQ model over southern Northwest China during spring and summer from 1981-2016, the wind erosion climatic erosivity of the WEQ model showed a decreasing trend for 1981-1992 and an increasing trend for 1992-2011 over southern Northwest China. According to a comparison between dust emission and wind erosion climatic erosivity, the 2 models have the ability to project changes in future wind erosion in northern China.

scholarly journals Quantitative Soil Wind Erosion Potential Mapping for Central Asia Using the Google Earth Engine Platform

2020 ◽  
Vol 12 (20) ◽  
pp. 3430
Author(s):  
Wei Wang ◽  
Alim Samat ◽  
Yongxiao Ge ◽  
Long Ma ◽  
Abula Tuheti ◽  
...  
Keyword(s):  
Wind Speed ◽  
Central Asia ◽  
Wind Erosion ◽  
Large Scale ◽  
Google Earth ◽  
Geospatial Data ◽  
Aral Sea ◽  
Erosion Modeling ◽  
Soil Wind Erosion ◽  
Google Earth Engine

A lack of long-term soil wind erosion data impedes sustainable land management in developing regions, especially in Central Asia (CA). Compared with large-scale field measurements, wind erosion modeling based on geospatial data is an efficient and effective method for quantitative soil wind erosion mapping. However, conventional local-based wind erosion modeling is time-consuming and labor-intensive, especially when processing large amounts of geospatial data. To address this issue, we developed a Google Earth Engine-based Revised Wind Erosion Equation (RWEQ) model, named GEE-RWEQ, to delineate the Soil Wind Erosion Potential (SWEP). Based on the GEE-RWEQ model, terabytes of Remote Sensing (RS) data, climate assimilation data, and some other geospatial data were applied to produce monthly SWEP with a high spatial resolution (500 m) across CA between 2000 and 2019. The results show that the mean SWEP is in good agreement with the ground observation-based dust storm index (DSI), satellite-based Aerosol Optical Depth (AOD), and Absorbing Aerosol Index (AAI), confirming that GEE-RWEQ is a robust wind erosion prediction model. Wind speed factors primarily determined the wind erosion in CA (r = 0.7, p < 0.001), and the SWEP has significantly increased since 2011 because of the reversal of global terrestrial stilling in recent years. The Aral Sea Dry Lakebed (ASDLB), formed by shrinkage of the Aral Sea, is the most severe wind erosion area in CA (47.29 kg/m2/y). Temporally, the wind erosion dominated by wind speed has the largest spatial extent of wind erosion in Spring (MAM). Meanwhile, affected by the spatial difference of the snowmelt period in CA, the wind erosion hazard center moved from the southwest (Karakum Desert) to the middle of CA (Kyzylkum Desert and Muyunkum Desert) during spring. According to the impacts of land cover change on the spatial dynamic of wind erosion, the SWEP of bareland was the highest, while that of forestland was the lowest.

Paleomagnetic Investigation of Lake Lahontan Sediments and Its Application for Dating Pluvial Events in the Northwestern Great Basin

1997 ◽  
Vol 47 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Joseph C. Liddicoat ◽  
Robert S. Coe
Keyword(s):  
Lake Sediment ◽  
Great Basin ◽  
Secular Variation ◽  
Lacustrine Sediments ◽  
River Valley ◽  
Middle Pleistocene ◽  
Truckee River ◽  
Pyramid Lake ◽  
Dating Methods ◽  
Paleomagnetic Secular Variation

AbstractA comparison of paleomagnetic secular variation in sediment of Pleistocene Lake Lahontan in the northwestern Great Basin with secular variation in lake sediment in the Mono Basin, California, indicates that Lake Lahontan was in the valley of the Truckee River between Pyramid Lake and Wadsworth, Nevada, from about 19,000 to 13,000 yr B.P. The secular variation in older Lake Lahontan sediment in the Truckee River valley has the general features of secular variation in middle Pleistocene lacustrine sediments near Rye Patch Dam, Nevada, 125 km to the east. On the basis of field mapping and tephrochronology, the sections of older lacustrine sediments are not coeval. The apparent, but erroneous, correlation of those sediments emphasizes the need for multiple dating methods when paleomagnetic secular variation is used to date stratigraphy.

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