检索结果-南通市图书馆

Onset of xiashu loess deposition in southern China by 0.9 Ma and its implications for regional aridification

Science China Earth Sciences 2018年第3期61卷 256-269页

作者： Xusheng LI Zhiyong HAN Huayu LU Yingyong CHEN Yang LI Xiaokang YUAN Yuwen ZHOU Mengyao JIANG Cunjuan LV School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210023 China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China College of Environment and Planning Henan University Kaifeng 475001

The xiashu loess is a typical Quaternary eolian deposit in southem China and represents an important terrestrial paleoclimate archive in this low-latitude monsoon region. However, the chronological framework of xiashu loess deposition has yet to be established. Determining the timing of the onset of xiashu loess deposition will allow researchers to better understand late Quaternary aridification across the Asian continent, the evolution of the East Asian monsoon and regional environmental changes in subtropical regions. Therefore, in this study, a systematic chronological study of the xiashu loess is conducted to answer this question. For the first time, magnetostratigraphic classification reveals that the Matuyama/Bnmhes （M/B） reversal is present in the xiashu loess at two sites in Jiangsu Province, the Qingshan profile at Yizheng and the Dagang core in Zhenjiang. Based on the results of magnetostratigraphy and optically stimulated luminescence （OSL） dating, the age of the lower boundary of the xiashu loess is estimated to be approximately 0.9 Ma. Consequently, this xiashu loess deposit is the oldest reported to date and is comparable in age to the red soil deposit in Xuancheng, Anhui Province. The onset of xiashu loess deposition by 0.9 Ma represents the further expansion of arid range in Asia in the late Quaternary in response to significant aridification and winter monsoon strengthening in this subtropical region. We suggest that these climate changes were primarily driven by global cooling and an increase in high-latitude ice volume in the Northern Hemisphere and that the initiation of xiashu loess accumulation was a regional response of southern China to the 0.9 Ma global cooling event.

关键词： xiashu loess Chronology Magnetic stratigraphy Aridification East Asian monsoon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mineral Composition and Weathering of Soils Derived from xiashu loess

引用

Pedosphere 1992年第2期2卷 135-145页

作者： DENGYOU－JUN MAYI－JIE 等 InstituteofSoilScience AcademiaSinicaP.O.Box821Nanjing210008（China） InstituteofSoilScience Academia

Mineralogical, physical and chemical analyses of the soils derived from xiashu loess were carried out. The primary minerals of these soils were found to be mainly composed of light minerals, such as quartz, feldspar and mica, with traces of heavy minerals. Clay minerals, more complicate in composition, were dominated by hydromica, accompanied by smectite, vermiculite, chlorite, kaolinite, 2:1/1:1 randomly interstratified minerals and small amounts of quartz, goethite, lepidocrocite and hematite, Clay minerals were characterized by low crystallinity and fine particle size. In light of the quartz/ feldspars ratio of the 0.01-0.05mm silt fraction, and the clay mineral composition, the freeness of iron oxide, and the silica/ sesquioxide and silica/ alumina ratios in < 0.002mm clay fraction, it is concluded that the weathering intensity of these soils was lower than those of red soil and yellow earth, but higher than that of brown earth, and that the soil allitization, depotassication and hydroxylation of clay minerals increased from west to east and from north to south geographically. However, this general tendency did not coincide exactly with the gradual alteration of the geographic coordinates, and in some places, a reverse tendency also appeared, which could be attributed to the influence of some soil forming factors such as parent material and microtopography.

关键词： evolution primary minerals secondary minerals weathering xiashu loess

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chemical weathering intensity and element migration features of the xiashu loess profile in Zhenjiang, Jiangsu Province

引用

Journal of Geographical Sciences 2008年第3期18卷 341-352页

作者： CHEN Yingyong LI Xusheng HAN Zhiyong YANG Shouye WANG Yongbo YANG Dayuan School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China State Key Laboratory of loess and Quaternary Geology Institute of Earth Environment CAS Xi＇an 710075 China State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China

The chemical weathering intensity and element migration features of the xiashu loess profile in Zhenjiang are studied in this paper.（1）The xiashu loess profile underwent moderate chemical *** seems that the precipitation is a more important factor than the temperature in controlling the process of the chemical weathering.（2）The major elements such as Si,K,Na,Ca,Mg,Mn and P were migrated and leached,while the elements Fe and Ti were slightly *** migration features of the major elements reveal that the xiashu loess finished the primary process of chemical weathering characterized by leaching of Ca and Na,and almost reached the secondary process characterized by leaching of *** the elements Sr and Ga,other trace elements such as Th,Ba,Cu,Zn,Co,Ni,Cr and V were *** might be caused by both the biogeochemical process and the adsorption of trace elements by clay mineral and organic materials.（3）The difference of element migration down the xiashu loess profile reveals that the climate was warm and wet at the early-middle stage of the middle *** the end of the middle Pleistocene,it became dry and *** the early stage of the Late Pleistocene,the paleoclimate became warm and wet *** a whole,the paleoclimate generally became drier and cooler in this region from the beginning of the middle Pleistocene.

关键词： xiashu loess chemical weathering element migration Zhenjiang

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：