Climatic and tectonic controls on strath terraces along the upper Weihe River in central China

2016 ◽  
Vol 86 (3) ◽  
pp. 326-334 ◽  
Author(s):  
Hongshan Gao ◽  
Zongmeng Li ◽  
Yapeng Ji ◽  
Baotian Pan ◽  
Xiaofeng Liu
Keyword(s):  
Yellow River ◽  
Central China ◽  
Fluvial Deposits ◽  
The Past ◽  
River Incision ◽  
System A ◽  
Fluvial Incision ◽  
Quaternary Climate ◽  
Field Investigations ◽  
Weihe River

AbstractThe Weihe River in central China is the largest tributary of the Yellow River and contains a well-developed strath terrace system. A new chronology for the past 1.11 Ma for a spectacular flight of strath terraces along the upper Weihe River near Longxi is defined based on field investigations of loess—paleosol sequences and magnetostratigraphy. All the strath terraces are strikingly similar, having several meters of paleosols that have developed directly on top of fluvial deposits located on the terrace treads. This suggests that the abandonment of each strath terrace by river incision occurred during the transition from glacial to interglacial climates. The average fluvial incision rates during 1.11—0.71 Ma and since 0.13 Ma are 0.35 and 0.32 m/ka, respectively. These incision rates are considerably higher than the average incision rate of 0.16 m/km for the intervening period between 0.71 and 0.13 Ma. Over all our results suggest that cyclic Quaternary climate change has been the main driving factor for strath terrace formation with enhanced episodic uplift.

Sedimentary characteristics of muddy deposits in sandy braided fluvial system: A case study from outcrops of the Jurassic Yungang Formation in the Datong Basin, Central China

2020 ◽  
Vol 8 (3) ◽  
pp. SM139-SM149
Author(s):  
Yuming Liu ◽  
Luxing Dou ◽  
Xiaoxu Ren ◽  
Jiagen Hou
Keyword(s):  
Depositional Environments ◽  
Central China ◽  
Shanxi Province ◽  
Fluvial System ◽  
Fluvial Systems ◽  
Sedimentary Characteristics ◽  
Fluvial Deposits ◽  
Datong Basin ◽  
System A ◽  
Sedimentary Architecture

The sandbodies within braided fluvial deposits are important reservoirs for the oil fields in China, and they usually have complex sedimentary architecture. A lot of research has been concentrated on characterizing the architecture of the sandbodies. Based on the observation that muddy deposits are commonly well preserved in fluvial deposits, we find that understanding the contact relationship between the muddy deposits and surrounding sand bodies can help characterize the depositional process of sandy braided fluvial systems. We have determined the effectiveness of this idea by characterizing a well-exposed outcrop of sandy braided fluvial system in the Datong Basin, Shanxi Province of China. We first define six muddy lithofacies by integrating the thickness of the muddy deposits, the morphology of the muddy deposit, and the lithofacies of surrounding sand deposits. The six muddy lithofacies include floodplain muddy deposits between intermittent channel complex, lateral covering muddy deposits and fall-silt seam muddy deposits between migrated bar complex, muddy gravel deposits in erosional bar complex, and channel-fill muddy deposits and gully-fill muddy deposits in abandoned bar complex. We then analyze the depositional environments according to the defined muddy lithofacies. We finally build the architecture of the outcrops by integrating the lithofacies of sand deposits and evolution of the depositional environments deduced from the muddy lithofacies.

Spatiotemporal pattern mining of drought in the last 40 years in China based on the SPEI index and space-time cube

2021 ◽  
Author(s):  
Dehe Xu ◽  
Qi Zhang ◽  
Yan Ding ◽  
De Zhang
Keyword(s):  
North China ◽  
Pattern Mining ◽  
Space Time ◽  
Central China ◽  
Spatiotemporal Pattern ◽  
Severe Drought ◽  
Monthly Precipitation ◽  
Hotspot Analysis ◽  
The Past ◽  
Significant Difference

AbstractDrought is a common natural disaster that greatly affects the crop yield and water supply in China. However, the spatiotemporal characteristics of drought in China are not well understood. This paper explores the spatial and temporal distributions of droughts in China over the past 40 years using multiscale standardized precipitation evapotranspiration index (SPEI) values calculated by monthly precipitation and temperature data from 612 meteorological stations in China from 1980 to 2019 and combines the space-time cube (STC), Mann-Kendall (M-K) test, emerging spatiotemporal hotspot analysis, spatiotemporal clustering and local outliers for the analysis. The results were as follows: 1) the drought frequency and STC show that there is a significant difference in the spatiotemporal distribution of drought in China, with the most severe drought in Northwest China, followed by the western part of Southwest China and the northern part of North China. 2) The emerging spatiotemporal hotspot analysis of SPEI6 over the past 40 years reveals two cold spots in subregion 4, indicating that future droughts in the region will be more severe. 3) A local outlier analysis of the multiscale SPEI yields a low-low outlier in western North China, indicating relatively more severe year-round drought in this area than in other areas. The low-high outlier in central China indicates that this region was not dry in the past and that drought will become more severe in this region in the future.

scholarly journals The Museum System of Modern Kazakhstan: Classification and Typology of Museums

2021 ◽  
Vol 9 (2) ◽  
pp. 79-89
Author(s):  
Abay Satubaldin ◽  
Kunikey Sakhiyeva
Keyword(s):  
National Level ◽  
Regional Level ◽  
District Level ◽  
Soviet System ◽  
Provincial Level ◽  
The Past ◽  
System A ◽  
The Subject ◽  
First Time

This article discusses the museum system of modern Kazakhstan and offers, for the first time ever, a classification and typology of the country’s museums.In recent years in independent Kazakhstan, on the basis of the Soviet system, a modern museum network has been formed which currently lists 250 museums. Among them are 17 national-level museums, 54 at the regional level, 73 at the provincial level, 103 branches of regional- and district-level museums and four private museums.The purpose of this article is to analyse the museum system of modern Kazakhstan and develop a classification and typology of the country’s museums.In the course of the study, conducted in 2017–2018, data was collected on the activities of museums at the national, regional and district levels over the past seven years. From the results of this investigation, the museums of Kazakhstan were systematized according to the subject or topic of the museum (e.g. history, art, scientific), its affiliation (national, regional district), and by size, measured by number of employees.

Anthropogenic and Climatic Factors Differentially Affect Waterbody Area and Connectivity in an Urbanizing Landscape: A Case Study in Zhengzhou, China

Land ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1070
Author(s):  
Chang Liu ◽  
Emily S. Minor ◽  
Megan B. Garfinkel ◽  
Bo Mu ◽  
Guohang Tian
Keyword(s):  
Yellow River ◽  
Climatic Factors ◽  
Landscape Connectivity ◽  
Aquatic Organisms ◽  
Open Water ◽  
Central China ◽  
Water Pipeline ◽  
Landsat Satellite ◽  
The City ◽  
Over Time

Urbanization alters the distribution and characteristics of waterbodies, potentially affecting both the habitat availability and connectivity for aquatic wildlife. We used Landsat satellite imagery to observe temporal and spatial changes in open-water habitats in Zhengzhou, a rapidly growing city in central China. We classified open water into six categories: perennial rivers, seasonal rivers and streams, canals, lakes, ponds, and reservoirs. From 1990 to 2020, in 5-year intervals, we identified, counted, and measured the area of each kind of waterbody, and we used a model selection approach with linear regressions to ask which climate and anthropogenic drivers were associated with these changes. We also used Conefor software to examine how these changes affected the landscape connectivity for waterfowl. Over the study period, lakes and canals were the only waterbody types to show statistically significant changes in surface area, increasing by 712% and 236%, respectively. Changes in lakes and canals were positively correlated with the length of water pipeline in the city. The connectivity of waterbodies fluctuated over the same period, mirroring fluctuations in the perennial Yellow River. Ponds contributed very little to landscape connectivity, and the importance of reservoirs decreased over time. Conversely, canals played an increasingly important role in landscape connectivity over time. Counterintuitively, the connectivity of waterbodies increased in the built-up part of the city. Our results show that urbanization can have unexpected effects—both positive and negative—on the connectivity and area of open-water habitats. These effects are likely to be important for waterfowl and other aquatic organisms.

scholarly journals DESIGN OF A DETACHED BREAKWATER SYSTEM

1974 ◽  
Vol 1 (14) ◽  
pp. 83
Author(s):  
Osamu Toyoshima
Keyword(s):  
Present Author ◽  
Design Method ◽  
Beach Erosion ◽  
The Past ◽  
Field Investigations ◽  
Experimental Works ◽  
Construction Works ◽  
Erosion Prevention ◽  
Sand Deposition

Beach erosion is one of the serious problem in Japan. As a countermeasure against beach erosion, many preventive works, such as sea walls and groins, have been constructed during the past 20 or more years. However, as the result of field investigations, it has become clear that sea walls and groins are not always effective on beach erosion prevention, and inversely, in some cases, they accelerate the beach erosion. Based on the above cognition, the author has proposed and tried to apply the detached breakwater system as a measure against beach erosion for the last 8 years. This is for the purpose of developing the sand deposition behind the breakwater. Therefore several experimental works of the detached breakwater system were carried out under the guidance of the present author, and most of these tests were successful. The design method of this system was composed by the author on the basis of the result of field investigations, which have been conducted for more than 8 years. The numerous construction works of detached breakwaters have been carried out in accordance with the design method proposed in this paper, and the effectiveness of detached breakwaters has been proved on the several coasts in Japan where severe beach erosion occurs.

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