Aragonite-calcite transformation in fossil snail shells of loess sequences in Loess Plateau, Central China

2005 ◽  
Vol 50 (9) ◽  
pp. 891 ◽  
Author(s):  
Xuefen SHENG
2005 ◽  
Vol 39 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Xuefen Sheng ◽  
Jun Chen ◽  
Junfeng Ji ◽  
Yunxia Sui

2005 ◽  
Vol 50 (9) ◽  
pp. 891-895 ◽  
Author(s):  
Sheng Xuefen ◽  
Chen Jun ◽  
Cai Yuanfeng ◽  
Chen Yang ◽  
Ji Junfeng

Clay Minerals ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 525-532 ◽  
Author(s):  
Junfeng Ji ◽  
Jun Chen ◽  
Huayu Lu

AbstractIllite, the predominant component of the clay fraction of the Chinese loess, has been studied by X-ray diffraction (XRD) in 33 samples taken from the Holocene palaeosol (S0), the last glacial loess (L1) and the last interglacial palaeosol (S1) in the Louchuan loess section of the Loess Plateau in China. The XRD investigations indicate that it is mainly a 2M1 dioctahedral mineral with crystallinity values ranging from 0.23 to 0.36°Δ2θ (CIS Index). The 2M1 polytype illites with low IC values preclude a pedogenic formation of illites in the surface horizons of aridic and semi-aridic soils or deserts, and thus the clay mineral composition was largely determined by provenance. The illites are considered to be of detrital origin derived from pre-existing sediments and very low- to low-grade metamorphic rocks, eroded from the northern part of the Tibetan Plateau. The clay content of the loess and palaeosols was largely controlled by the strength of the winter monsoon, rather than by effects of in situ pedogenetic processes.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 544
Author(s):  
Xuhong Zhao ◽  
Lifang Kang ◽  
Qian Wang ◽  
Cong Lin ◽  
Wei Liu ◽  
...  

As a potential energy crop with high biomass yield, Miscanthus lutarioriparius (M. lutarioriparius), endemic to the Long River Range in central China, needs to be investigated for its acclimation to stressful climatic and soil conditions often found on the marginal land. In this study, traits related to acclimation and yield, including survival rates, plant height (PH), stem diameter (SD), tiller number (TN), water use efficiency (WUE), and photosynthetic rates (A), were examined for 41 M. lutarioriparius populations that transplanted to the arid and cold Loess Plateau of China. The results showed that the average survival rate of M. lutarioriparius populations was only 4.16% over the first winter but the overwinter rate increased to 35.03% after the second winter, suggesting that plants having survived the first winter could have acclaimed to the low temperature. The strikingly high survival rates over the second winter were found to be 95.83% and 80.85%, respectively, for HG18 and HG39 populations. These populations might be especially valuable for the selection of energy crops for such an area. Those individuals surviving for the two consecutive winters showed significantly higher WUE than those measured after the first winter. The high WUE and low stomatal conductance (gs) observed in survived individuals could have been responsible for their acclimation to this new and harsh environment. A total of 61 individuals with productive growth traits and strong resistance to cold and drought were identified for further energy crop development. This study showed that the variation of M. lutarioriparius held great potential for developing energy crops following continuous field selection.


2013 ◽  
Vol 89 (02) ◽  
pp. 153-161 ◽  
Author(s):  
Yang Zhao ◽  
Xinxiao Yu

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.


Antiquity ◽  
2017 ◽  
Vol 91 (355) ◽  
Author(s):  
J. Rawson

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.


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