检索结果-南通市图书馆

Geochemical changes across the ordovician-silurian transition on the Yangtze Platform,South China

Science China Earth Sciences 2009年第1期52卷 38-54页

作者： YAN DeTian CHEN DaiZhao WANG QingChen WANG JianGuo Key Laboratory of Tectonics and Petroleum Resources Ministry of EducationChina University of GeosciencesWuhan 430074China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The trace element and rare earth element(REE) variations across the ordovician-silurian succession are presented from two outcrop sections on the Yangtze Platform:the Nanbazi section,Guizhou Province,deposited in a shallow platform interior setting,and the Wangjiawan section,Hubei Province,deposited in a deeper basinal environment.Geochemical analysis of closely spaced samples through three intervals,the Wufeng,Guanyinqiao and Longmaxi,revealed vast palaeoceanographic changes.Some geochemical proxies,including Th/U,Ni/Co,V/Cr,and V/(V+Ni) ratios,together with sedimentary facies and biotic data,indicate that an anoxic condition on the most of the Yangtze Platform during the Wufeng and Longmaxi intervals,but an oxic condition during the Guanyinqiao time.The shift of the anoxic to the oxic environment during the Guanyinqiao time coincided with a global sea-level lowstand,in parallel with the global glaciation.The Longmaxian anoxic environment was a result of a global sea-level rise,which may be synchronized with a mainly catastrophic event in the latest ordovician.Although the two sections generally show similar variation patterns of trace and REE concentrations and some element ratios,a minor difference occurs between the Wangjiawan and Nanbazi sections,likely reflecting a difference in depositional setting during the accumulation.Such an oceanic oxygen-level variation may add a useful constraint to the current arguments on the cause and consequence of the latest ordovician mass extinction.

关键词： rare earth elements trace elements paleo-redox proxies mass extinction ordovician-silurian boundary Yangtze Platform

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

Expansion of the Cathaysian Oldland through the ordovician-silurian transition:Emerging evidence and possible dynamics

引用

Science China Earth Sciences 2010年第1期53卷 1-17页

作者： RONG JiaYu ZHAN RenBin XU HongGen HUANG Bing YU GuoHua State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Zhejiang Institute of Geological Survey Hangzhou 311203China

Located northwest of the Jiangshan-Shaoxing Fault Zone,western and northwestern Zhejiang and northeastern Jiangxi provinces experienced major changes in bio-and litho-facies and paleogeography through the ordovician-silurian transition (late Katian,Hirnantian,and early Rhuddanian),as manifested by stratigraphic,paleontologic and synecologic records.Three geographic units under consideration are South,Central,and North areas.The western margin of the South area was occupied by the Huaiyu Mountains,whereas the other two parts were covered by the Zhe-Gan Sea during late Katian (Late ordovician) time.In the early stage of the Changwu Formation deposition (late Katian),the sea was deepening northeastward,but with shallower conditions in the southwest and deeper conditions in the northeast.During mid to late stages of Changwu Formation deposition (latest Katian),the sea became much shallower and the sea bottom was uplifted substantially,which occurred somewhat prior to the global trend.During the Hirnantian (latest ordovician) and early Rhuddanian (earliest silurian),the study region became a shallow bay under expansion of the Cathaysian Oldland.There occurred a major drop of sea level and great changes in benthic biota with the occurrence of many new immigrants through the ordovician-silurian transition,which are closely related to a unique regional orogeny.The Yangtze and Cathaysian blocks may have amalgamated within the South China Paleoplate during this interval to cause the continuous uplifting and northwestward expansion of the Cathaysian Oldland.

关键词： Cathaysian Oldland Jiang-Shao Fault Zone ordovician-silurian transition biostratigraphy synecology paleogeography

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

K-bentonite beds and high-resolution integrated strati- graphy of the uppermost ordovician Wufeng and the lowest silurian Longmaxi formations in South China

引用

Science China Earth Sciences 2003年第11期46卷 1121-1133页

作者：苏文博何龙清王永标龚淑云周湖云 School of Earth Sciences and Resources China University of Geosciences Beijing 100083 China Yichang Institute of Geology and Mineral Resources China Geological Survey Yichang 443003 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Test Center China University of Geosciences Wuhan 430074 China

More than 20 K-bentonite beds were discovered from the Wufeng Formation and the lowest Longmaxi Formation in two sections, both adjacent to the ordovician-silurian (O-S) bound-ary and located in Tongzi, Guizhou Province and Yichang, Hubei Province, some 500 km apart from each other in South China. This indicates that many volcanic eruptions occurred near the southeast margin of the Yangtze Platform between the latest ordovician and the earliest silurian. Mainly through biostratigraphic and sequence stratigraphic studies, it was found that almost all these far-apart K-bentonite beds may be correlated with each other. This is the first time that a succession of volcanic ash deposits with high potential of correlation was discovered within a strata interval on the main platforms of China. Therefore, these K-bentonite beds may afford ex-cellent event-marker beds helpful to high-resolution research in integrated stratigraphy as well as other lines of research on the O-S boundary in South China.

关键词： K-bentonite bed, event-marker, high-resolution integrated stratigraphy, ordovician-silurian Boundary, Wufeng & Longmaxi formations, Yangtze Platform.

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

Method and practice of deep favorable shale reservoirs prediction based on machine learning

引用

Petroleum Exploration and Development 2022年第5期49卷 1056-1068页

作者： CHENG Bingjie XU Tianji LUO Shiyi CHEN Tianjie LI Yongsheng TANG Jianming State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China Key Laboratory of Earth Exploitation and Information Technology of Ministry of Education Chengdu University of TechnologyChengduSichuan 610059China School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu 611731China Yangtze Delta Region Institute of University of Electronic Science and Technology of China Huzhou 313000China Southwest Oil and Gas Branch Company SINOPECChengdu 610041China

A set of methods for predicting the favorable reservoir of deep shale gas based on machine learning is proposed through research of parameter correlation feature analysis principle, intelligent prediction method based on convolution neural network(CNN), and integrated fusion characterization method based on kernel principal component analysis(KPCA) nonlinear dimension reduction principle.(1) High-dimensional correlation characteristics of core and logging data are analyzed based on the Pearson correlation coefficient.(2) The nonlinear dimension reduction method of KPCA is used to characterize complex high-dimensional data to efficiently and accurately understand the core and logging response laws to favorable reservoirs.(3) CNN and logging data are used to train and verify the model similar to the underground reservoir.(4) CNN and seismic data are used to intelligently predict favorable reservoir parameters such as organic carbon content, gas content, brittleness and in-situ stress to effectively solve the problem of nonlinear and complex feature extraction in reservoir prediction.(5) KPCA is used to eliminate complex redundant information, mine big data characteristics of favorable reservoirs, and integrate and characterize various parameters to comprehensively evaluate reservoirs. This method has been used to predict the spatial distribution of favorable shale reservoirs in the ordovician Wufeng Formation to the silurian Longmaxi Formation of the Weirong shale gas field in the Sichuan Basin, SW China. The predicted results are highly consistent with the actual core, logging and productivity data, proving that this method can provide effective support for the exploration and development of deep shale gas.

关键词： Sichuan Basin ordovician-silurian shale gas reservoir prediction machine learning convolution neural network kernel principal component analysis

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

SHRIMP zircon U-Pb dating from K-bentonite in the top of ordovician of Wangjiawan Section,Yichang,Hubei,China

引用

Science China Earth Sciences 2008年第4期51卷 493-498页

作者： HU YanHua ZHOU JiBin SONG Biao LI Wei SUN WeiDong Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sci-encesGuangzhou 510640China Beijing SHRIMP Center Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of Earth and Space Science University of Science and Technology of ChinaHefei 230026China Graduate University of the Chinese Academy of Sciences Beijing 100049China

The Global boundary Stratotype Section and Point (GSSP) for the base of the Hirnantian Stage (the latest stage of the ordovician System) is defined at a point 0.39m below the base of the Kuanyinchiao Bed in the Wangjiawan North Section, which is the upper most "golden spike" of the ordovician. However, this "golden spike" is lack of reliable geochronology data. This article gives a sensitive high resolution ion microprobe (SHRIMPII) zircon U-Pb dating for a K-bentonite sample from the Kuany-inchiao Bed in the Wangjiawan North Section. The age of the K-bentonite sample is 443.2±1.6 Ma, that is to say, the isotopic age of the uppermost of Hirnantian Stage, the point of ordovician-silurian boundary, should be near to, but slightly younger than 443.2±1.6 Ma. This age is identical to the Ordovi-cian-silurian boundary age 443.7±1.5 Ma as declared by International Commission on Stratigraphy (ICS). So, this research provides some good geochronlogical data for the Hirnantian Stage and the ordovician-silurian boundary as well as the global correlation.

关键词： Hirnantian zircon SHRIMP bentonite ordovician-silurian boundary

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

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

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：