Tonian Tectonic-Strata Regions and their Geological Significance in China     

XU Yadong  ZHANG Kexin  HE Weihong  YU Yang  KOU Xiaohu  SONG Bowen  LUO Mansheng  WANG Lijun  MA Zhongjie  YANG Fengli 《《地质学报》英文版》2020,94(4):914-941

The continent of China developed through the coalescence of three major cratons(North China, Tarim and Yangtze) and continental micro-blocks through the processes of oceanic crust disappearance and acceretionary-collision of continental crusts. The strata of the Chinese continental landmass are subdivided into 12 tectonic-strata regions. Based on the composition of geological features among the three main cratons, continental micro-blocks and other major global cratons, their affinities can be preliminarily deduced during the Tonian period, using evidence from sedimentary successions, paleobiogeography, tectonic and magmatic events. The Yangtze and Tarim cratons show that they have close affinities during the assembly-dispersal milestone of the Rodinia Supercontinent. The sedimentary record and magmatic age populations in the blocks suggest that there was a widespread, intensive magmatic event that resulted from a subduction process during ～1000–820 Ma, related to continental rifting around the Yangtze and Tarim cratons. However, they differ greatly from the North China Craton. The continental micro-blocks in the Panthalassic Ocean could have some missing connection with the North China Craton that persisted until the Middle-Late Devonian. In contrast, the Alxa Block showed a strong affinity with the Tarim Craton. The revised Tonian paleogeography of the Rodinia Supercontinent is a good demonstration of how to show the relationship between the main cratons and the continental micro-blocks.  相似文献   

Late Cambrian to Early Silurian Granitic Rocks of the Gemuri Area, Central Qiangtang, North Tibet: New Constraints on the Tectonic Evolution of the Northern Margin of Gondwana     

WANG Haitao  ZHAI Qingguo  HU Peiyuan  ZENG Lingsen  TANG Yue  ZHU Zhicai 《《地质学报》英文版》2020,94(4):1007-1019

The Paleozoic tectonic framework and paleo–plate configuration of the northern margin of Gondwana remain controversial. The South Qiangtang terrane is located along the northern margin of Gondwana and records key processes in the formation and evolution of this supercontinent. Here, we present new field, petrological, zircon U-Pb geochronological, and Lu-Hf isotopic data for granitic rocks of the Gemuri pluton, all of which provide new insights into the evolution of the northern margin of Gondwana. Zircon U-Pb dating of the Gemuri pluton yielded three concordant ages of 488.5 ± 2.1, 479.9 ± 8.9, and 438.5 ± 3.5 Ma. Combining these ages with the results of previous research indicates that the South Qiangtang terrane records two magmatic episodes at 502–471 and 453–439 Ma. These two episodes are associated with enriched zircon Hf isotopic compositions(εHf(t) =-10.1 to-3.9 and-16.6 to-6.5, respectively), suggesting the granites were formed by the partial melting of Paleoproterozoic–Mesoproterozoic metasedimentary rocks(Two–stage Hf model ages(TCDM) = 2094–1704 and 2466–1827 Ma, respectively). Combining these data with the presence of linearly distributed, contemporaneous Paleozoic igneous rocks along the northern margin of Gondwana, we suggest that all of these rocks were formed in an active continental margin setting. This manifests that the two magmatic episodes within the Gemuri area were associated with southward subduction in the Proto-(Paleo-) Tethys Ocean.  相似文献   

克拉通盆地构造转折区中-新生界构造特征及其控藏意义——以鄂尔多斯盆地西南部镇泾地区延长组为例     

张园园  任战利  何发岐  崔军平  杨桂林  王琨  吉园园 《岩石学报》2020,36(11):3537-3549

基于三维地震、测井、岩矿测试等资料，分析了镇泾地区中生界断裂体系特征与成因，结合源岩热演化与储层物性反演结果，恢复了长8段油气成藏的动态演化过程，探讨了中生代以来构造活动对长8段油气成藏的影响作用。研究认为鄂尔多斯盆地内部镇泾构造转折区构造变形受盆地边缘影响明显，发育复杂断裂体系，构造特征及演化对油气藏的形成与分布有重要控制作用。结果表明：（1）中生界北西向、北东东向、近东西向3组断裂发育，平面上呈雁列式带状展布，剖面上为高陡产状且小断距错动。印支期北西向主断裂走滑明显，中、晚燕山期北东向断裂活动加强，喜山期北东东向次级断裂密度增大，并派生大量剪切裂隙。（2）长8段油藏经历了晚三叠世储集层、烃源岩层初始沉积形成，早白垩世初期少量低熟油近源充注形成岩性油藏，早白垩世末成熟油快速输导形成受断层及裂缝控制的构造-岩性油气藏，晚白垩世以来早期油藏调整等4个阶段。（3）印支运动控制了烃源岩及储层展布范围，I类北西向走滑断裂控制了镇泾地区中生界构造格局；中、晚燕山运动加速烃源岩热演化进程，并改善储层物性，II类断裂活动，为烃类输导提供垂向通道；喜山运动使先存中生界断裂活动，控制油气调整范围及油藏差异富集；其中北东东向II类张性或张扭性断裂导流性能好，是最为有效的富油断层。  相似文献   

四川省康定县三碉金矿床岩矿石化学成分特征及构造环境          下载免费PDF全文

何阳阳  蒋双宇  邓成雪 《地质找矿论丛》2020,35(2):129-137

康定县境内的三碉金矿床是大渡河金矿成矿集中区内的典型矿床。本文基于野外实地调查取样、实验室分析测试工作,通过对岩矿石地球化学特征及构造环境进行研究,结果表明:1)从无矿石英→含矿石英,SiO_2、Al_2O_3、CaO等含量均有所减少,TiO_2、MnO、K_2O、Na_2O等变化范围不大,Fe_2O_3和FeO等则有明显的增高。2)斜长角闪岩的原岩为基性火山岩,δEu主要表现为正异常特征;黑云母花岗岩具有中钾钙碱性特征,形成于造山晚期,δEu表现为明显的负异常特征。即三碉金矿的形成过程中,硅铝质矿物在减少,载金金属矿物在增多;含矿流体混染和交代长英质岩浆减弱抵消负铕异常导致斜长角闪岩δEu值逐渐过渡为正异常;黑云母花岗岩δEu为负异常,是早期斜长石的晶出带走Eu作用的结果。3)矿区断裂与矿床的形成密切相关,为成矿流体的上升运移提供了有利的通道,并提供含矿石英脉的沉聚空间。  相似文献   

EFFECTS OF Mg~(2+), NaCl, CITRIC ACID, AND OTHER FACTORS ON SYNTHESIS AND ACCUMULATION OF β-CAROTENE IN DUNALIELLA SALINA     

金海洙  郭承华  贺君  王青华  姜竹茂  孙福章 《中国海洋湖沼学报》1998,(4)

Therearemorethan4Ookindsofcarotenoids,aboutl(X)ofwhichcanbeObtainedfromoceanicmicrobesandalgae,sooceanicalgaeareconsideredthemostimPOrtanre-sourceofnaturalcarotenoids(Becker,l982).DunaliellaSalinahasdrawnnmehattentionfromanuInberofcountriesrecently,asmoreandmorestudiesshowedthatthisunicellularalgacanaccumulatelargeamountsof5-caroteneundercertainenvironmentalconditions(Li,1988).SuInInallzingthebiosyntheticmechanismof3-carotene,weknowthatacetylCoAandCO2arethehasicInaerialsfOrSYthesizing3-…  相似文献   

陕南川北志留系兰多维列统特列奇阶宁强组的生物礁   总被引：2，自引：0，他引：2  

李越  陈旭 《沉积学报》1998,16(3):124-131

志留纪兰多维列世（Llandovery）扬子地台持续上升。特列奇期（Telychian）griestoniensis笔石带上部至spiralis-grandis带代表的时限内,地处扬子地台西北缘的宁强湾,在温暖浅海的环境中沉积了宁强组巨厚的泥页岩,其中夹含8套碳酸盐岩。在与之对应的8期小型局限碳酸盐岩台地的不同部位建造了生物礁和生物滩。生物礁的类型包括骨架礁、生物层和灰泥丘。生物礁群落由底栖固着的造礁珊瑚、苔藓虫、海百合、藻类、层孔虫,以及非固着的附礁生物腕足类、鹦鹉螺、三叶虫等组成。通过宁强广元地区不同地点和层位的生物礁组合分析,论述它们在生态组合、生长形状和发育过程中的多样性。  相似文献   

Paleomagnetic result of the Lower-Cretaceous from Luanping basin,Hebei Province and its tectonic implications*     

Zhiming  Sun  Zhenyu  Yang  Xinghua  Ma  Yue  Zhao 《中国科学:地球科学(英文版)》1998,41(2):43-50

A paleomagnetic study of about 95 samples from 16 sites sampled in the Early Cretaceous in Luanping basin in Hebei Province was reported. Stepwise thermal demagnetization was used to isolate magnetic components. Most samples have a characteristic direction with a high temperature component above 500°C. The tectonic-corrected data areD = 347.8°,I = 50.4°, α₉₅ = 7.l°, and the corresponding pole position is at 76.1°N, 346.3°E,with dp =6.4°,dm = 3.8°, paleolatitude λ = 31.1°N. This result indicates a counterclockwise post-Cretaceous rotation of 30.7° ±9.8° with respect to the stable Ordos basin in the west of North China Block, and a non-significant northward motion. This rotation could be related to local fault action or structural detachment, or regional NNW-NWWward motion and collision of Kula-Pacific plate with eastern China since the Early Cretaceous.

  相似文献   

Paleomagnetic result of the Lower-Cretaceous from Luanping basin,Hebei Province and its tectonic implications*     

Sun Zhiming  Yang Zhenyu  Ma Xinghua  Zhao Yue 《中国科学D辑(英文版)》1998,41(2):43-50

A paleomagnetic study of about 95 samples from 16 sites sampled in the Early Cretaceous in Luanping basin in Hebei Province was reported. Stepwise thermal demagnetization was used to isolate magnetic components. Most samples have a characteristic direction with a high temperature component above 500°C. The tectonic-corrected data areD = 347.8°,I = 50.4°, α₉₅ = 7.l°, and the corresponding pole position is at 76.1°N, 346.3°E,with dp =6.4°,dm = 3.8°, paleolatitude λ = 31.1°N. This result indicates a counterclockwise post-Cretaceous rotation of 30.7° ±9.8° with respect to the stable Ordos basin in the west of North China Block, and a non-significant northward motion. This rotation could be related to local fault action or structural detachment, or regional NNW-NWWward motion and collision of Kula-Pacific plate with eastern China since the Early Cretaceous.  相似文献   

On Palaeozoic Tectonics in the Alxa Region, Inner Mongolia, China     

WU Tairan  HE Guoqi  ZHANG ChenGeology Department  Peking University  Beijing 《《地质学报》英文版》1998,72(3):256-263

Two ophiolitic melange belts in the Late Carboniferous formations have been discovered recently in the Alxa region. One is in the Engger Us fault and possesses properties of oceanic crust. The other is in the Badain Jaran fault and shows properties of a back-arc basin. These two faults, together with the Yagan fault, constitute the important boundaries of tectonic units in the Alax region. The four tectonic units delimited by these faults are different in rock assemblages, metamorphism and geochemistry. They reflect the nature of tectonic environments in which they are found. The tectonic units may be traced and correlated to the eastern and western neighbouring areas. The formation and evolution process of the units and their interaction in the Alxa region may be described in terms of the evolution of the Palaeo-Mongolian Ocean and its continental margins.  相似文献   

Magmatic Network Structure of Volcanic Rocks in the Shengli Oilfield, Eastern China     

HE Ying  ZHU Xingguo Department of Geology  Northwest University  Xi''an  Shaanxi  XU PeicangXi''an Institute of Geology  Chinese Academy of Geological Sciences  Xi''an  Shaanxi 《《地质学报》英文版》1998,72(2):191-197

Types of polymerized molecular network structure and degree of bond breakdown for glass phases of magmatic inclusions and glassy matrix in volcanic rocks from the Shengli oilfield have been defined by the laser Raman spectroscopic investigation. There are significant differences in types of polymerized molecular network structure and degree of bond 'breakdown of the magmatic glass phases between the non-CO2 and COa gas pools: magmatic glass phases of fluid inclusions and matrix in volcanic rocks from the CO2 gas pool contain more sheet network molecules and have a greater degree of bond beakdown than those from the non-CO2 gas pool; and when gas bubbles occur in evolving magma, magma saturated with volatile components has more sheet network molecules. The results suggest the magma-degassing mechanism of the formation of CO2 gas pools in the Shengli oilfield.  相似文献