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Filamentous cyanobacteria fossils and their significance in the Permian-Triassic boundary section at Laolongdong,Chongqing

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Filamentous cyanobacteria fossils and their significance in ...

中国科学院地质与地球物理研究所2008学术年会

作者： JIANG HongXia,WU YaSheng~+ & CAI ChunFang key laboratory of mineral resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,china

The microbial communities blooming immediately after the end-Permian mass extinction represent abnormally extreme environments,and vary in different *** this study,filamentous cyanobacterial biota was found in the strata after the extinction in the famous Permian-Triassic boundary section at Laolongdong,Chongqing,southwest *** thin sections,the filamentous cyanobacterial fossils are below 1 mm in length,and generally taper to one end,with the widest diameter up to 0.08 *** of them are curved,indicating that they are soft in *** walls are composed of cryptocrystalline to microcrystalline *** filaments have round cross section,and are internally filled with micrites and fine sparry calcites,which indicate that the filaments are originally *** are randomly distributed in the rocks,but in some places,they tend to be distributed in radial *** filamentous organisms are morphologically similar to Rivularia of Rivulariaceae,Cyanobacteria Phylum,but with calcified sheaths,and are tentatively regarded as an indeterminate new species in Rivularia:Rivularia *** are photosynthetic autotrophic,and can survive in dysoxic *** blooming of this organism and the absence of other organisms may indicate that the environment was oxygendeficient and shallow,since this photosynthetic autotrophic organism needed to live within photic zone.

关键词： microbial fossil end-Permian Permian-Triassic boundary cyanobacteria Rivularia

Geochemistry of the Middle Dovenian Picritic Rocks of the South Margin of Altay Orogenic Belt: Implications for the Tectonic Setting and Petrogenesis

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Geochemistry of the Middle Dovenian Picritic Rocks of the So...

火山作用与地球层圈演化——全国第四次火山学术研讨会

作者： Zhao Li~1 Zhang Zhaochong~(1,2) Yan Shenghao~3 Chen Bailin~4 Zhou Gang~5 HeYongkang~5 Chai Fengmei~2 He Lixin~5 1. State key laboratory of geological processes and mineral resources, china university of geosciences, Beijing 100083 2. Institute of Geology, Chinese Academy of geological Sciences, Beijing 100037 3. Institute of mineral resources, Chinese Academy of geological Sciences, Beijing 100037 4. Institute of Geomechanics, Chinese Academy of geological Sciences, Beijing 100081 5. No. 4 geological Party, Xinjiang Bureau of Geology and resources, Aertai, Xinjiang

＜正＞ The Altay orogenic belt, Xinjiang Uygur Autonomous Region in NW china, represents one of the important sites of juvenile crustal growth during the Phanerozoic time. However, some important issues, e.g., tectonic evolution and petrogenesis, still remain controversial. Two layers of the picritic rocks in the south margin of the Altay orogenic belt, were discovered in the lower part of marine volcanic-sedimentary

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Early cretaceous granitoids and their implications for the collapse of the Dabie orogen,eastern china:SHRIMP zircon U-Pb dating and geochemistry

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Early cretaceous granitoids and their implications for the c...

中国科学院地质与地球物理研究所2007学术年会

作者： Haijin Xu~(a,b),Changqian Ma~b,Kai Ye~(a,*) a State key laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences. Beijing,100029.P.O.Box 9825,PR china b Faculty of Earth Sciences.china university of geosciences,wuhan,430074.PR china

Two stages of early Cretaceous post-orogenic granitoids are recognized in the Dabie orogen,eastern china,which recorded processes of extensional collapse of the *** early stage granitoids(～132 Ma) are foliated hornblende quartz monzonites and porphyritic *** are of high-K calc-alkaline series and metaluminous to weakly peraluminous,with high KO and low MgO contents(Mg values:32.0-46.0),they contain high Sr,low Y and heavy rare earth elements(HREE),and have high Sr/Y and(La/Yb) ratios,without clear negative Eu,Sr and Ti *** early stage deformed granitoids have adakitic geochemical compositions and are equilibrated with residues rich in garnet and poor in anorthite-rich plagioclase,and thus indicate the existence of an over-thickened(>50 km) crustal root beneath the orogen at～132 *** later stage granitoids(～128 Ma) are undeformed fine-grained ***-grained K-feldspar granites and coarse-grained K-feldspar *** belong to a peraluminous and high-K calc-alkaline to shoshonite series,and display a flat HREE pattern and have strong negative *** and Ti anomalies,with low Sr/Y and(La/Tb) *** late stage granitoids are equilibrated with residues rich in anorthite-rich plagioclase,hornblende,ilmenite/titanite and poor in garnet,indicating that the crust of the Dabie orogen became thinner(28 *** zircon U-Pb ages and changing compositional trends for these two stages of granitoids indicate that the over-thickened crust formed by the Triassic continental subduction/collision under the Dabie orogen remained until the early Cretaceous,and collapsed quickly in a few million years during the early Cretaceous.

关键词： Early Cretaceous Granitoids Extensional collapse The Dabie orogen

Extrapolate well logs based on the constrained interpolation algorithm

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Extrapolate well logs based on the constrained interpolation...

中国科学院地质与地球物理研究所2008学术年会

作者： Liu Hongwei,Liu Hong,Qin Yueshuang,and Shou Hao 1.Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,china. 2.State key laboratory of geological processes and mineral resources,china university of geosciences,Beijing,100083 3.The Exploratory development Institute of Daqing Oilfield Limited Liability Company,Daqing 163712,china. 4.Research Institute of Exploration and Development of Chinese Petroleum,Beijing 100083,china.

Based on a detailed analysis of differences between seismic data and well logs, we discuss the problem of matching seismic traces and well logs and present a new matching method based on event search in instantaneous phase which greatly improves seismic *** method is based on flattening events in instantaneous phase to compare the seismic traces to the well log traces with the same *** calculate the coefficients using the singular value decomposition method to extrapolate the well *** a result,the events in the seismic profile are continuous and match well with well *** apply this method to the Mao-2 well in Daqing Oilfield with good results.

关键词： events flattening SVD method instantaneous phase correlation

北秦岭超高压榴辉岩中长英质脉体的锆石U-Pb年龄及其地质意义

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地球科学 2018年第2期43卷 389-400页

作者：何宇赵宇洁张文祥王浩周光颜吴元保中国地质大学地质过程与矿产资源国家重点实验室湖北武汉430074 中国地质大学地球科学学院湖北武汉430074 中国科学院岩石圈演化国家重点实验室北京100029 中国科学院地质与地球物理研究所北京100029

北秦岭地区的早古生代超高压变质作用是整个秦岭-桐柏-红安-大别-苏鲁造山带内最古老的超高压变质记录,代表华南与华北板块之间最早的一期增生碰撞事件,然而目前对于该地区早古生代的构造演化过程仍存在较大争议.对北秦岭官坡超高压榴... 详细信息

北秦岭地区的早古生代超高压变质作用是整个秦岭-桐柏-红安-大别-苏鲁造山带内最古老的超高压变质记录,代表华南与华北板块之间最早的一期增生碰撞事件,然而目前对于该地区早古生代的构造演化过程仍存在较大争议.对北秦岭官坡超高压榴辉岩中的一个长英质脉体开展了详细的锆石形态学、微量元素和U-Pb年代学研究.结果表明,脉体中的锆石呈自形的棱柱状晶形,发育弱的振荡环带、面状分带或无明显分带特征,具有高的HREE、Y、U含量,低的Th含量和Th/U比值,说明锆石生长自含水熔体.另外,这些变质锆石具有LREE亏损、HREE相对富集的配分模式以及明显的Eu负异常,表明含水熔体形成于角闪岩相退变质过程.锆石的206Pb/238 U加权平均年龄为494±10Ma(MSWD=2.2),与北秦岭超高压变质作用的峰期年龄(490.4±5.8Ma)在误差范围内基本一致.北秦岭地体经历深俯冲作用之后发生快速折返,并在折返过程中发生角闪岩相退变质作用诱发俯冲板片部分熔融产生含水熔体.

关键词：北秦岭长英质脉体锆石U-Pb 锆石微量元素快速折返地球化学地质年代学

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不同层序岩相中的不稳定带和岩石的特征变化

沉积与特提斯地质 1995年第2期16卷 150-153页

作者： Yu.K. Burlin(geological Department,Moscow Lomonosov university,V-234 Vorobjevy Cory,Moscow,119899, Russia) 俄罗斯莫斯科罗蒙诺索夫大学地质系

盆地形成的原因包括；构造圈深部地带物质的不稳定状态、软流圈厚度的增加和继而地壳厚度的减小。大多数沉积盆地均有一些高能不稳定层，反映了岩石特征的非线性交换。在不同岩石类型的不同深度，密度、孔隙度、水饱和度等的异常均不相... 详细信息

盆地形成的原因包括；构造圈深部地带物质的不稳定状态、软流圈厚度的增加和继而地壳厚度的减小。大多数沉积盆地均有一些高能不稳定层，反映了岩石特征的非线性交换。在不同岩石类型的不同深度，密度、孔隙度、水饱和度等的异常均不相同。决定异常存在的主要作用是岩石的构造一组分特征和导热性、导电性。采用与深度和ＰＴ因子一致的温度计算法来建立不同岩石类型和不同地球动力条件和热力条件下岩石特征变化的计算机模型或许是重要的。密度、孔隙度等的非线性变化决定了不同流体循环的环型流动的存在，不稳定层的预测是矿产预测之关键。

关键词：不稳定带特征变化层序岩石特征孔隙度岩相古地理不稳定层岩石类型密度盆地形成

从板缘碰撞到陆内造山:华南东南缘早古生代造山作用演化

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地球科学 2018年第2期43卷 333-353页

作者：徐亚军杜远生中国地质大学地质过程与矿产资源国家重点实验室湖北武汉430074 中国地质大学生物地质与环境地质国家重点实验室湖北武汉430074 中国地质大学地球科学学院湖北武汉430074

华南的广西运动被认为是发生在早古生代的陆内造山作用,然而触发陆内变形的地球动力学机制仍然不清.广西运动形成了泥盆系与下伏岩石之间广泛的不整合面以及分布在局部地区的下古生界内部的多个不整合面.广西运动期间的构造热事件和古... 详细信息

华南的广西运动被认为是发生在早古生代的陆内造山作用,然而触发陆内变形的地球动力学机制仍然不清.广西运动形成了泥盆系与下伏岩石之间广泛的不整合面以及分布在局部地区的下古生界内部的多个不整合面.广西运动期间的构造热事件和古生物响应时间在460~380Ma,时间上对应于奥陶系和泥盆系之间的多个不整合,而分布在华南南缘的寒武系和奥陶系之间的不整合面(郁南运动)仅与少量的530~480Ma之间的变质事件相当,但是却同步于广泛分布在东冈瓦纳北缘的造山事件.华南南部寒武系-奥陶系不整合面上下的碎屑锆石年代学研究表明,早古生代华南与印度北缘相连,而三亚地块在寒武纪是澳大利亚西缘的一部分,直到奥陶纪才与华南拼合,同步于冈瓦纳最终的聚合.郁南运动之后,华夏板块处于冈瓦纳内部,来自冈瓦纳东缘造山作用的应力向大陆内部传播,在具有弱流变学性质的南华盆地聚集,导致盆地构造反转,触发了广西运动.早古生代的华南经历了从板缘碰撞(郁南运动)到陆内造山(广西运动)的演化过程.

关键词：广西运动郁南运动加里东运动陆内造山作用华南构造地质

甘肃滴水山金矿不同构造-岩相带岩石地球化学特征及构造控矿机理探讨

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西北地质 2018年第1期51卷 88-103页

作者：杨永春刘家军王学银陈杰薛小文张聪任锡中国地质大学地质过程与矿产资源国家重点实验室北京100083 甘肃省地质矿产勘查开发局第四地质矿产勘查院甘肃酒泉735000

滴水山金矿床位于北祁连加里东褶皱带的西段,分布于北西西向剪切带内,通过野外实地观察和镜下鉴定、样品测试,对该剪切带内Au2矿体构造-岩相特征及其地球化学元素变化特征进行了研究,结果表明:(1)该剪切带存在2期变形,早期为由北向南斜... 详细信息

滴水山金矿床位于北祁连加里东褶皱带的西段,分布于北西西向剪切带内,通过野外实地观察和镜下鉴定、样品测试,对该剪切带内Au2矿体构造-岩相特征及其地球化学元素变化特征进行了研究,结果表明:(1)该剪切带存在2期变形,早期为由北向南斜冲的韧-脆性剪切变形,晚期为斜向下滑的脆性变形。(2)根据元素分析结果,Au元素含量从安山质晶屑凝灰岩带→糜棱岩化安山质晶屑凝灰岩带→蚀变碎裂岩带→金矿化蚀变碎裂岩带逐步增高。根据相关性分析,Au与Ag相关性最好,其次为Pb、Mo,与As、Hg相关性一般。研究认为,滴水山金矿床北西西向剪切带早期韧-脆性变形有利于成矿元素的活化迁移,为Au元素的运移和初步富集提供了通道,晚期脆性变形主要形成各种张裂隙和构造破碎带,由于构造体制发生转换,导致Au元素的再次富集形成金矿体。

关键词：滴水山金矿剪切带构造-岩相带主微量元素构造体制转换

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青白口纪宏观藻类生物群及其古地理意义

地球科学 2018年第2期43卷 475-490页

作者：刘傲然冯庆来田立富中国地质大学地球科学学院湖北武汉430074 河北地质大学资源学院河北石家庄050031 中国地质大学地质过程与矿产资源国家重点实验室湖北武汉430074

Rodinia超级大陆演化作为前寒武纪重要科学问题,一直备受关注.古生物地理区系作为解决古板块地理位置重建的有效手段,在Rodinia超级大陆恢复方面应用较少.龙凤山生物群是新元古代早期宏观藻类代表性生物群之一,其以ChuariaTawuia-Longfe... 详细信息

Rodinia超级大陆演化作为前寒武纪重要科学问题,一直备受关注.古生物地理区系作为解决古板块地理位置重建的有效手段,在Rodinia超级大陆恢复方面应用较少.龙凤山生物群是新元古代早期宏观藻类代表性生物群之一,其以ChuariaTawuia-Longfengshania为组合特征的宏观藻类在新元古代早期(1 000~780Ma)广泛分布在赤道及低纬度地区的温暖滨海静水环境中.根据全球现有可靠的生物群落资料,进行了古生物地理分析,结果表明:此时期宏观藻类可划分为一个赤道附近低纬度地区宏观藻类生物域,域内包括以含底栖固着Longfengshania为特征的华北-加拿大(Chuaria-Tawuia-Longfengshania)区和仅有简单浮游藻类为特征的扬子-印度(Chuaria-Tawuia)区;古生物地理分布特征表明青白口纪Rodinia超级大陆中华北板块与劳伦古陆相邻、位于超大陆东缘,而扬子克拉通靠近印度板块、位于超大陆西部.

关键词：龙凤山生物群古生物地理宏观藻类 Rodinia超级大陆古生物