欢迎您！东篱公司
退出
-
申报数据库
-
立项数据库
-
成果数据库
-
项目获奖数据库
中文摘要：
运用岩石磁学和地球化学相结合的方法对宝鸡剖面S5和S5古土壤的磁性特征进行了详细对比分析，结果表明S5古土壤层Rb／Sr比值较高，S5古土壤形成期气候温暖湿润，成壤程度比S5时期强。S5层亚铁磁性矿物含量低于S5层，反铁磁性矿物主要为针铁矿；而S5层的反铁磁性矿物主要为赤铁矿。S5层土体表面及土壤空隙中可见大量黑褐色的铁锰胶膜分布，由于沉积后土壤长时期处于偏干或偏湿的氧化、还原交替环境中，细粒的磁铁矿和／或磁赤铁矿、赤铁矿溶解转化成褐铁矿、针铁矿等弱磁性矿物，主要转化成在局域湿润环境下能够稳定存在的针铁矿，这种磁性矿物的转化可能导致了成壤强的S5古土壤超顺磁亚铁磁性矿物含量的减少和磁化率的降低。
英文摘要：
The magnetic susceptibility（MS）has been widely used as a proxy of summer monsoon,whicla is Daseu on an important fact that the MS achieves the highest value in the most developed paleosol S5 ,while lower values in less weathered loess layer in the Central Chinese Loess Plateau（CLP）. However,in Baoji loess section, the MS of Ss is the lowest value within the top 6 paleosols（ S0, S1 ...S5）, which contradicts above normal situation. Baoji（34°25 ＇N, 107°07＇E） is located in the southern edge of CLP, north foot of Qinling Mountains. The present climate is warm temperate semi-humid with mean annual precipitation （MAP） of more than 700ram （ up to 1100mm in Qinling areas） ,the rain distribution is uneven （60% rain falls between July and Sep. ）, and mean annual temperature （MAT）of 12℃ （25.4℃ in July）. Pedogenic condition in Baoji,such as precipitation,is better than the Central Loess Plateau,for example MAP 654mm in Xifeng （35°46＇N, 107°41 ＇E） and MAP 555mm in Lingtai （ 35°33＇N, 107°31＇E）. In order to find out its mechanism,the samples were collected from the Baoji loess-paleosol sequence since S5, with sampling interval 30cm. The results of rock magnetism and geochemical measurements for Baoji S5 and S3 samples show, that ratio Rb/Sr of Ss samples was higher than that of S3, indicating that S5 was a better-developed paleosol unit, stronger chemical weathering than S3. The climate condition during S5 period was confirmed to be the warmest and wettest for the last O. 5Ma. The S3 paleosol was formed under oxidation environment, under such pedogenic conditions, maghemite and hematite were formed simultaneouly, the anti-ferromagnetic minerals are mainly hematite, superparamagnetic（SP） maghemite is the main contributor to the magnetic properties. However, the contents of ferrimagnetic minerals in S5 samples are lower than that of S3 samples. With pedogenic developing,the proportion of ferrimagnetic component reduces in S5 while the content of anti-f
同期刊论文项目
同项目期刊论文
A long-term increasing aridification and cooling trend at the Chinese Loess Plateau during the Plioc
Paleoclimatic evolution of Holocene loess and discussion of the sensitivity of magnetic susceptibili
Dendroclimatic response of Picea crassifolia along an altitudinal gradient in the eastern Qilian Mou
Late Quaternary (30.7-9.0 cal ka BP) vegetation history in Central Asia inferred from pollen records
A high-resolution record of Holocene environmental and climatic changes from Lake Balikun (Xinjiang,
Spatial and temporal variety of prehistoric sites and its influencing factors in the upper Yellow Ri
Glacier changes from 1966-2009 in the in the Gongga Mountains, on the south-eastern margin of the Qi
A 16-ka lake-level record inferred from macrofossils in a sediment core from Genggahai Lake, northea
Influence of household biogas digester use on household energy consumption in a semi-arid rural regi
A comparative study of radiocarbon dating charcoal and charred seeds from the same flotation samples
Precipitation variations and possible forcing factors on the Northeastern Tibetan Plateau during the
Glacier variations in response to climate change from 1972 to 2007 in the western Lenglongling mount
Comparison of topsoil magnetic properties between the loess region in Tianshan Mountains and Loess P
Interannual precipitation variations in the mid-latitude Asia and their association with large-scale
Process of paleofloods in Guanting basin, Qinghai Province, China and possible relation to monsoon s
Soil Microbial and Enzymatic Activities Across a Chronosequence of Chinese Pine Plantation Developme
A 457-year reconstruction of precipitation in the southeastern Qinghai-Tibet Plateau, China using tr
Patterns and dynamics of tree-line response to climate change in the eastern of Qilian Mountains, no
Compound-specific hydrogen isotopes of long-chain n-alkanes extracted from topsoil under a grassland
Magnetostratigraphy and palaeoenvironmental records for a Late Cenozoic sedimentary sequence from La
Late Cenozoic orogenic history of Western Qinling inferred from sedimentation of Tianshui basin, nor
Cenozoic tectonic uplift history of Western Qinling: Evidence from sedimentary and fission-track dat
Stable carbon and oxygen isotopic study of carbonate along a loess/paleosol section located in south
Conifer stomata analysis in paleoecological studies on the Loess Plateau: an example from Tianchi La
Annual precipitation reconstruction since AD 775 based on tree rings from the Qilian Mountains, nort
The ultrafine component in Chinese loess and its variation over the past 7.6 Ma: implications for th
Holocene vegetation and climate histories in the eastern Tibetan Plateau: controls by insolation-dri
Eocene to Pliocene exhumation history of the Tianshui-Huicheng region determined by Apatite fission-
Spatiotemporal drought variability for central and eastern Asia over the past seven centuries derive
Is the maximum carbon number of long-chain n-alkanes an indicator of grassland or forest? Evidence f
Variation and paleoclimatic significance of organic carbon isotopes of Ili loess in arid Central Asi
A high-resolution multi-proxy record of late Cenozoic environment change from central Taklimakan Des
Palaeomagnetic and palaeoenvironmental study of two parallel sections of late Cenozoic strata in the
Vegetation history, climate change and human activities over the last 6200 the Liupan Mountains in t
Magnetic properties and correlation with heavy metals in urban street dust: A case study from the ci
期刊信息
位置：