检索结果-南通市图书馆

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Zhifeng Liu Qingsong Liu José Torrent Vidal Barron Pengxiang Hu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Graduate University of Chinese Academy of Sciences Departamento de Agronomia Universidad de CordobaEdificio C4Campus de Rabanales14071 CordobaSpain

soils are natural archives of paleoclimates,especially for *** magnetic parameters of soils are of great interest for paleoenvironmental and paleoclimatic ***,magnetite, maghemite,hematite,and goethite are the main minerals controlling the magnetic properties of soils. The application of magnetic methods in large areas is,however,limited due to the potential effects of parent ***,magnetic measurements were conducted on modern soil profiles along a North-South transect in Shaanxi Province,China,to test a new magnetic proxy,defined as the ratio between the absolute frequency dependent susceptibility and the hard isothermal remanence magnetization(x/HIRM)for paleoprecipitation *** specifically,xand HIRM were used as semi-quantitative proxies for the ferrimagnets(magnetite and maghemite)and hematite concentrations,*** proxy x/ HIRM,estimated from the scatter plots of xand HIRM ranges between 4.5 and 97.6×10mAand systematically increases with the mean annual precipitation(MAP)fiom 300 to 1000 mm(x/HIRM= 0.124×MAP-31.5,R=0.92)with an error of±70 mm for the paleoprecipitation estimation,but is less related to mean annual temperature(MAT)(R=0.29 for a MAT range of 8-15℃).For MAPsoil profile located in an area where MAP>1000 mm, the x/HIRM value was only 17.8×10mAas the likely result of reductive dissolution or alteration,the effect being more marked for ferrimagnets than for *** summary,this new paleoclimatic transfer function has potential to predict MAP for Holocene soils with MAP<1000 mm,providing that there is no reductive dissolution or alteration of the iron oxides and the effect of other influential factors(***

关键词： magnetic proxy paleoprecipitation climate transfer function modern soil

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Acyclic Alkanes in the soil over Heshang Cave in Qingjiang, Hubei Province

引用

Journal of China University of Geosciences 2006年第2期17卷 115-120页

作者：蒲阳黄俊华黄咸雨崔景伟胡超涌 State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Laboratory of Biogeology and Environmental Geology Ministry of Education China University of Geosciences Wuhan430074 China

The reports that relate to the biomarker＇s fate and characteristics of the modern soil in the karst area are very lacking. By using gas chromatography-mass spectrometry （GC-MS）, a series of biomarkers were identified from the soils collected over Heshang cave （和尚洞） in Qingjiang （清江）, Hubei （湖北） Province. The distribution of n-alkanes is mainly from C2s to C33 in carbon number, with a maximum at C31. They have a strong odd-over-even carbon number predominance. These characteristics represent an input mainly from higher plants. The lipid parameters, including CPIh （carbon preference index）, Rb/t（ratio of lower- to higher-molecular-weight homologues） and ACL （average chain length）, show comparable trends with depth, probably reflecting vegetation change and microbial degradation. Series of monomethylalkanes and diploptene are present in the extractable organic matter; they might be derived from soil microbes, cyanobacteria in particular.

关键词： biomarker modern soil n-alkanes vegetation cyanobacteria.

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

Variation in Solvent-Extractable Lipids and n-Alkane Compound-Specific Carbon Isotopic Compositions with Depth in a Southern China Karst Area soil

引用

Journal of Earth Science 2010年第4期21卷 382-391页

作者：崔景伟黄俊华 Philip A Meyers 黄咸雨李婧婧刘文贵 State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing) State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(wuhan) Department of Geological Sciences The University of Michigan Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences(wuhan)

Because literatures about the lipid compositions of modern soils in karst areas are scarce, we have studied the soil horizons overlying the Heshang （和尚） Cave that has provided paleoclimate records from speleothem lipid contents. Our analysis reveals a series of n-alkanes, free fatty acids, n-alkanols and n-alkan-2-ones distribution and relative abundance changing with the depth, and in which the ratios of the lower molecular weight to higher molecular weight n-alkanes, free fatty acids, n-alkanols and n-alkan-2-ones have a peak at a subsurface depth of 5 to 10 cm. An accompanying peakin 17β（H）, 21β（H）-hop-22（29）-ene （diploptene） and a shift to less negative n-alkane carbon isotopic values also identify this layer in the karst soil. This pattern indicates the existence of a subsurface soil layer in which the microorgan- isms that produce these compounds are espe- cially abundant. The carbon isotopic values of individual plant wax n-alkanes are about 3%0 greater at the base of the 30- to 40-cm soil profile than in the surface layer, probably as a result ofselective microbial degradation of n-alkanes from different primary sources. The lipids and carbon iso- topic values of individual plant wax n-alkanes study of the overlying soil show a strong microbial activity in this karst soil and help in interpreting the lipid compositions and specific carbon isotopic value of n-alkanes of the stalagmites of the Heshang Cave for paleoenvironmental reconstructions.

关键词： lipid biomarker modern soil karst area compound-specific carbon isotopic value n -alkan-2-one.

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：