Variation of Zr/Rb ratios on the Loess Plateau of Central China during the last 130000 years and its implications for winter monsoon

2002 ◽  
Vol 47 (15) ◽  
pp. 1298 ◽  
Author(s):  
Lianwen LIU
Keyword(s):  
Loess Plateau ◽  
Winter Monsoon ◽  
Central China ◽  
The Loess Plateau

scholarly journals Effects of climatic variability and human activity on runoff in the Loess Plateau of China

2013 ◽  
Vol 89 (02) ◽  
pp. 153-161 ◽  
Author(s):  
Yang Zhao ◽  
Xinxiao Yu
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Water Conservation ◽  
Human Activities ◽  
Climatic Variability ◽  
Land Use Changes ◽  
Annual Runoff ◽  
Central China ◽  
Vegetative Cover ◽  
The Loess Plateau

The Loess Plateau in north-central China has a long history of human activities. As a result of climate change, deforestation and sparse vegetative cover, the region suffers from water shortages and severe soil erosion, significantly influencing efforts for sustainable social development. In order to understand the impacts of climatic variability and human activities on runoff and other hydrological factors in this region, the Luoyugou catchment and its paired catchments (Qiaozidong and Qiaozixi) were selected. Statistical analysis indicated precipitation did not vary significantly whereas the annual runoff decreased from 1986 to 2008, with an abrupt change in 1994. Actual evapotranspiration (AET) increased slightly but not significantly. A comparison of runoff in the paired catchments showed land use changes reduced runoff by more than 38% under the same rainfall conditions. Human activities were the strongest contributor to changes in runoff and AET, at 67% and 90% respectively, while the remaining contributor was climate variation. The influence of various human activities on runoff is quite different, and soil-water conservation initiatives have a greater impact on runoff (about 41%). Thus, human activities were the primary reason for the reduction in runoff in the study catchment compared to climate. Greater emphasis should be given to afforestation and soil-water conservation measures.

scholarly journals Shimao and Erlitou: new perspectives on the origins of the bronze industry in central China

Antiquity ◽  
2017 ◽  
Vol 91 (355) ◽  
Author(s):  
J. Rawson
Keyword(s):  
Loess Plateau ◽  
Central China ◽  
Shaanxi Province ◽  
The Loess Plateau ◽  
International Conference ◽  
Large Stone ◽  
Northern Edge ◽  
Bronze Casting

Over the last five years, excavation of a large, stone, fortified site at Shimao, on the northern edge of the Loess Plateau in Shaanxi Province, China, has radically changed our understanding of the events that precipitated the development of the first bronze casting in central China at Erlitou (Figure 1). An international conference on the Shimao site, held at Shenmu in August 2016, explored many aspects of this major discovery.

Grain Size of Quartz as an Indicator of Winter Monsoon Strength on the Loess Plateau of Central China during the Last 130,000 Yr

1995 ◽  
Vol 43 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Jule Xiao ◽  
Stephen C. Porter ◽  
Zhisheng An ◽  
Hisao Kumai ◽  
Shusaku Yoshikawa
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Loess Plateau ◽  
Winter Monsoon ◽  
Central China ◽  
Atmospheric Conditions ◽  
Dust Transport ◽  
Chinese Loess ◽  
Weathering Processes ◽  
Monsoon Strength

AbstractThe Chinese loess-paleosol sequence constitutes an important record of variations in Asian monsoon climate over the past 2.4 myr. Magnetic susceptibility of loess and paleosols has been used as a proxy for summer monsoon intensity, while median grain size has been regarded as a measure of the strength of winter monsoon winds that were responsible for most of the dust transport. However, median grain size is only an approximate index of winter monsoon strength because both paleosols and loess have been modified, to various degrees, by weathering processes that have produced pedogenic clay. The quartz component of loess and paleosols is largely unaffected by weathering processes and therefore constitutes a more reliable proxy index of monsoon wind strength. Median grain size (Qmd) and maximum grain size (Qmax) values of monomineralic quartz isolated from the loess-paleosol section at Luochuan in the central Loess Plateau are characterized by two main intervals during the last ca. 130,000 yr when these parameters were significantly greater than 9 and 85 μm, respectively, and three main intervals when they were lower. The data imply that the winter monsoon weakened during the intervals with low Qmd and Qmax values, which coincide with marine oxygen isotope stages 5, 3, and 1, and was strongest ca. 67,000 and 20,000 yr ago during isotope stages 4 and 2. However, both quartz grainsize records display second-order high-frequency, high-amplitude variations, which are lacking in the magnetic susceptibility record, that imply rapid and significant changes in atmospheric conditions that affect dust transport and deposition.

An EPR study on mollusk shells from loess-paleosol sequences in the Loess Plateau, central China

2005 ◽  
Vol 39 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Xuefen Sheng ◽  
Jun Chen ◽  
Junfeng Ji ◽  
Yunxia Sui
Keyword(s):  
Loess Plateau ◽  
Central China ◽  
The Loess Plateau ◽  
Mollusk Shells ◽  
Plateau Central

scholarly journals Chronology of the Baxie Loess Profile and the History of Monsoon Climates in China Between 17,000 and 6000 Years BP

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 818-825 ◽  
Author(s):  
Weijian Zhou ◽  
Zhisheng An ◽  
Benhai Lin ◽  
Jule Xiao ◽  
Jinzhao Zhang ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Organic Content ◽  
Central China ◽  
Organic Component ◽  
Monsoon Circulation ◽  
The Loess Plateau ◽  
Asian Summer ◽  
Loess Profile

The valley of the Baxie River, situated in the western region of the Loess Plateau in central China, contains a loess profile 15 m thick, which can be considered representative of loess-paleosol sequences formed over the last 17 ka. Both thermoluminescence (TL) determinations on fine-grained sediment (4–11 μm) and 14C determinations on various organic fractions of paleosols from the profile have provided an extremely useful chronological framework for these sequences. These sequences indicate a weakened summer monsoon during the last glacial maximum followed by a strengthening of the summer monsoon, beginning ca. 13 ka cal bp. An abrupt change to a weakened summer monsoon regime lasted from ca. 10.9 to 10.2 ka cal bp. The Asian summer monsoon circulation, recording the Holocene optimum, then increased and lasted from ca. 10.2 to 6 ka cal bp. The organic component of samples taken down the profile has δ13C values ranging from −21 to −24‰ with respect to the PDB standard. The more positive δ13C values suggest that the proportion of C4-type plants in river valleys of the Loess Plateau increased as Asian summer monsoon influence weakened, and C3-type vegetation increased as the summer monsoon influence strengthened. Magnetic susceptibility and organic content were low during loess deposition, also reflecting weakening of summer monsoon. Two 14C determinations on the humin fraction of the organic component near the top of the lower paleosol and the base of the upper paleosol complex gave ages of 10.2 and 10.9 ka cal BP, respectively. These ages mark the beginning and termination of a brief event involving increased dust influx under weakened summer monsoon conditions.

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