检索结果-南通市图书馆

Environmental and tectonic significance of Late Permian reefs in the Linxi and adjacent areas in Inner Mongolia of China

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2016年第7期59卷 1463-1476页

作者： TIAN Shu Gang ZHANG Yong Sheng GONG Yue Xuan LI Zi Shun GAO Lian Da ZHAI Da Xing ZHU Chang Wei institute of geology Chinese Academy of Geological Sciences institute of Mineral Resources Chinese Academy of Geological Sciences Department of Science and Technology Chinese Academy of Geological Sciences

Many plateau-edge reefs and reef mounds of the Late Permian have been discovered in Linxi County and adjacent areas of Inner Mongolia, China. These reefs verify that the Hinggan-Inner Mongolia Area was an open and unobstructed sea-trough in Late Permian. Facies and sequences of reef strata in Member 4 and Member 5 of the Linxi Formation were studied for information to reconstruct the closing process of the Linxi-Jiutai chasm in the sea-trough, i.e., to constrain subsidence, uplift, and final closing. Ages of the reef-bearing strata have been determined to be late and end of Late Permian, based on ranges or abundances of diverse fossils. Six reef-building organic assemblages were distinguished, representing different ecologic conditions, according to morphological functions and paleoecological adaptations of organisms including primarily sponges, bryozoans, and calcareous algae. Two types of shelf slopes, the gentle slope and the steep slope, have been interpreted for Member 4 and Member 5 of the Linxi Formation, based on the assemblages. The locations of outcrops, and types of these reefs delineate the north margin of Sino-Korea Platform, and define uplift and final closing of the Linxi-Jiutai chasm at the end of Late Permian.

关键词： Reefs Facies sequence Paleoecology Late Permian Inner Mongolia

Discovery of Paleogene palynological assemblages from the Wanbaogou Group-complex in western part of the Eastern Kunlun orogenic belt and its geological significance

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2006年第4期49卷 358-367页

作者： GUO Xianpu WANG Naiwen DING Xiaozhong ZHAO Min WANG Daning institute of geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

Wanbaogou Group-complex is a suit of melange aggregation of the EasternKunlun orogenic belt, which is divided into two parts, i.e. the exotic blocks and the matrix *** on stromatolite fossils yielded in the exotic blocks, the age of this group-complex was oncedefined to the Precambrian. Recently, two Paleogene palynological assemblages have been found insamples from the matrix strata of the Upper Part in this group-complex by the authors: in ascendingorder, the Al-nipollenites-Quercoidites assemblage of Late Eocene and theCaryapollenites-Pinuspollenites assemblage of Early Oligocene. Those results show that the matrixstrata of this melange were mainly formed in Paleogene, and the event causing mixture should be aHimalayan Movement Phase. This paper is designed to provide some detailed evidence for determiningthe age of the matrix strata in this group-complex based upon study at the Kunlunqiao Section, whichwould be of important geological significance for further understanding this group-complex as asuit of melange aggregation and establishing or improving the stratigraphic framework of the studiedregion. The new finding will certainly benefit from now on the investigation on geotectonic andsedimentary evolution of Eastern Kunlun.

关键词： wanbaogou group-complex paleogene palynological assemblages melangeaggregation the eastern Kunlun orogenic belt

Groundwater System Division and Description of Asia

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第4期90卷 1434-1443页

作者： ZHANG Fawang YI Qing CHENG Yanpei YUE Chen DONG Hua institute of Karst geology Chinese Academy of Geological Sciences institute of Hydrogeology and Environmental geology Chinese Academy of Geological Sciences

Based on landform, climate, river system, geological structure and hydrogeological structure and from the perspective of systematology, the groundwater system of Asia can be divided into 36 secondary groundwater systems under 11 primary ones by the intercontinental scale. This forms part of the work of the groundwater series map of Asia, which is compiled according to groundwater system division and evaluation of the total amount and types of aquifer, reflecting the large-scale features of groundwater resources in Asia. Systematic profiling of groundwater in this way provides a scientific basis for groundwater exploitation planning and management in Asia, and avoiding disputes over groundwater resources and the environment among Asian countries.

关键词： Asia groundwater system climate and topography division

Neoproterozoic Volcanic Rocks in the Southern Quruqtagh of Northwest China:Geochemistry,Zircon Geochronology and Tectonic Implications

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2013年第1期87卷 118-130页

作者： ZHANG Yingli WANG Zongqi YAN Zhen WANG Tao institute of Mineral Resources Chinese Academy of Geological Sciences institute of geology Chinese Academy of Geological Sciences

The Early Neoproterozoic Beiyixi Formation volcanic rocks of the southern Quruqtagh comprise mainly of a suite of tholeiitic basalts, alkaline andesites, and calc-alkaline rhyolites. The rhyolites are characterized by variably fractionated enrichment in light rare earth elements （LREE） and fiat in heavy rare earth elements （HREE）, and strongly negative Eu anomalies. Compared to the rhyolites, the andesites also exhibit enrichment in LREE and flat HREE （chondrite-normalized values of La/Yb,and La/Sm are 13.30-41.09, 3.18-6.89 respectively）. Their rare earth element patterns display minor negative Eu anomalies. Both of them exhibit coherent patterns with strongly to moderately negative anomalies of Nb, Zr, Ti, and Hf on spider diagrams. Two rhyolite and one andesite magmatic zircons with defined oscillatory zoning yielded weighted mean 206pb/23Su ages of 743 ± 7 Ma, 741±2 Ma, and 7274 Ma. These ages are interpreted to represent the timing of volcanic eruptions. According to geochemistry and rock type, these volcanic rocks formed within a continental island-arc environment following subduction of the oceanic crust during the Early Neoproterozoic period.

关键词： Quruqtagh Beiyixi Formation volcanic rocks geochemistry zircon geochronology,tectonic setting

Zircon U-Pb age, Lu-Hf Isotopic Characteristics and Origin of the Banshanping Granitoid Rocks in East Qinling Orogenic Belt

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2014年第3期88卷 766-779页

作者： LI Mingze WU Cailai LEI Min QIN Haipeng LIU Chunhua institute of geology Chinese Academy of Geological sciences

The Banshanping granitoid rocks distribute in the east of the North Qinling orogenic *** is a diorite-quartz diorite-granodiorite-granite series,spreading in a NW-SE direction,and intrudes into the Erlangping *** SiO2 content ranges from 57.04% to 76.56%,Na2O from 2.05% to 4.65%,K2O from 0.84% to 3.40%.Major element characteristics indicate that Banshanping granitoid rocks have properties of I type *** ranges from 36.51 ppm to 473.25 ppm,and LREE/ HREE ratios lie between 3.95 and *** Eu anomalies are not obvious in most samples,though there are obvious Nb,P and Ti positive *** zircon LA-ICP-MS ages of Banshangping granitoid rocks are 496.0±8.1 Ma-486.9±9.3 *** isotope shows that 176Hf/177Hf ratios range from 0.282721 to 0.282876,εHf（t） values from 8.5 to 14,all positive,and corresponding modal ages （TDM2） range from 559 Ma to 908 *** on Hf isotope characteristics and existing SmNd and Rb-Sr isotope data,we consider that the Banshanping granitoid rocks originate from mantlederived material,*** igneous rocks that formed in Neoproterozoic,and there may be a certain amount of crust-derived material during the formation of Banshanping granitoid rocks.

关键词： Banshanping granitoid rocks Zircon U-Pb chronology Lu-Hf isotope characteristics,material origin

Compressive Tectonics around Tibetan Plateau Edges

在线全文

学校读者我要写书评

暂无评论

Journal of China University of Geosciences 2009年第2期20卷 477-483页

作者：赵志新徐纪人 institute of geology Chinese Academy of Geological Sciences

Various earthquake fault types, mechanism solutions, stress field, and other geophysical data were analyzed for study on the crust movement in the Tibetan plateau and its tectonic implications. The results show that numbers of thrust fault and strike-slip fault type earthquakes with strong compressive stress near NNE-SSW direction occurred in the edges around the plateau except the eastern boundary. Some normal faulting type earthquakes concentrate in the Central Tibetan plateau. The strikes of fault planes of thrust and strike-slip faulting earthquakes are almost in the E-W direction based on the analyses of the Wulff stereonet diagrams of fault plane solutions. This implies that the dislocation slip vectors of the thrust and strike-slip faulting type events have quite great components in the N-S direction. The compression motion mainly probably plays the tectonic active regime around the plateau edges. The compressive stress in N-S or NE-SW directions predominates earthquake occurrence in the thrust and strike-slip faulting event region around the plateau. The compressive motion around the Tibetan plateau edge is attributable to the northward motion of the Indian subcontinent plate. The northward motion of the Tibetan plateau shortened in the N-S direction encounters probably strong obstructions at the western and northern margins.

关键词： thrust and strike-slip faulting earthquake compressive stress Tibetan plateau edge P-axes northward motion.

Static Corrections Methods in the Processing of Deep Reflection Seismic Data

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2014年第2期25卷 299-308页

作者： Xiaosan Zhu Rui Gao Qiusheng Li Ye Guan Zhanwu Lu Haiyan Wang institute of geology Chinese Academy of Geological Sciences

Statics are big challenges for the processing of deep reflection seismic data. In this paper several different statics solutions have been implemented in the processing of deep reflection seismic data in South China and their corresponding results have been compared in order to find proper statics solutions. Either statics solutions based on tomographic principle or combining the low-frequency components of field statics with the high-frequency ones of refraction statics can provide reasonable statics solutions for deep reflection seismic data in South China with very rugged surface topography, and the two statics solutions can correct the statics anomalies of both long spatial wavelengths and short ones. The surface-consistent residual static corrections can serve as the good compensations to the several kinds of the first statics solutions. Proper statics solutions can improve both qualities and reso- lutions of seismic sections, especially for the reflections of Moho in the upmost mantle.

关键词： deep reflection seismic data static correction field static refraction static tomographic static residual static correction.

Mesozoic basins and associated palaeogeographic evolution in North China

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2015年第2期4卷 189-202页

作者： Yong-Qing Liu Hong-Wei Kuang Nan Peng Huan Xu Peng Zhang Neng-Sheng Wang Wei An institute of geology Chinese Academy of Geological Sciences

In North China, the Mesozoic terrestrial basins, sedimentary palaeogeography and tectonic settings involved five evolutionary stages：（1） the Early-Middle Triassic, （2） the Late Triassic to Early-Middle Jurassic, （3） the Late Jurassic to early Early Cretaceous, （4） the middle-late Early Cretaceous and （5） the Late Cretaceous. The regional punctuated tectonic events occurred during these evolutionary stages. During the Early-Middle Triassic （stage 1）, the Xingmeng Orogenic Belt （XMOB, i.e., east- ern part of Central Asia Orogenic Belt, CAOB） of the northern North China was settled in the transition of tectonic environment from syn-orogenic compression to post-orogenic extension with intensive uplifting. It is a main provenance in the unified Ordos-North China *** united continental plate of China and the Qinling-Dabie-Sulu Orogenic Belt formed due to convergence and collision between the North China Plate and the Yangtze Plate along two suture zones of the Mianlue and the Shangdan in the terminal Middle Triassic. During the Late Triassic to the Early-Middle Jurassic （stage 2）, the Late Triassic mafic or alkaline rocks and intrusions occurred on the northern and southern margins of North China Craton （NCC） and XMOB, implying that intensified extension happened all over the North China （early phase of stage 2）. Additionally, in the late phase of stage 2, the basic volcanic- filing faulted basins were widely distributed in the northeastern North China during the Early- Middle Jurassic, including a series of smalt- to medium-sized basins with coal-bearing strata and some volcanic rocks in other areas of North China, which was the result of subduction of the Palaeo-Pacific Plate during the Early-Middle Jurassic. An active continental margin with accretionary complex developed in the eastern Heilongjiang of China, Japan and the Far East of Russia at that time. However, in the end of the Early-Middle Jurassic, because of the Yan- shanian orogeny characterized by com

关键词： Mesozoic basin orogenic belt tectonic zone palaeogeography North China

Ultramafic Blocks in Sumdo Region, Lhasa Block, Eastern Tibet Plateau: An Ophiolite Unit

在线全文

学校读者我要写书评

暂无评论

Journal of China University of Geosciences 2009年第2期20卷 332-347页

作者：陈松永杨经绥李源徐向珍 institute of geology Chinese Academy of Geological Sciences

Recently, an over 100 km long MORB-type eclogite belt of Permian was discovered in the Sumdo （松多） region of the Lhasa block, Tibet. A critical question thus is： what is the tectonic setting of the eelogite belt and is it related to an unrecognized suture in the region？ Further investigations show that there are some mafic and ultramafic rocks spacially associated with the eclogite belt in the region. Three ultramafic massifs were recognized in the Sumdo region, and called the Luomaling （罗马岭）, Gongbupala （贡布爬拉） and Qiazhasumdo （卡扎松多） massifs. All the massifs are fault-contacted with greenschist （Chasagang （岔萨岗） Formation） or muscovite-quartz schist （Mabuku （马布库） Formation）, and individuals are about 100 m×50 m in size extending in EW as the regional structure. All the ultramafic rocks have been entirely serpentinized, and the Gongbupala massif has been selected for study in geochemistry. Eleven chemical analyses of the rocks from the Gongbupala massif show a narrow range in contents： SiO2 （35.97-40.63） wt.%, MgO （37.02-38.60） wt.%, TiO2 （0.01-0.08） wt.%, Al2O3 （0.80-1.64） wt.%, （Na2O＋K2O） less than 0.1 wt.%, with high volatile contents （H2O＋CO2）（11.24-14.91） wt.%. After recalculation without H2O＋CO2, the mean values are SiO2 45.24 wt.%, MgO 43.54 wt.%, FeOT （7.45-9.97） wt.% （8.55 wt.% in average）, （MgO＋FeOT） 52.09 wt.%, Mg# （100×Mg/（Mg＋Fe＊）, where Fe＊ represents total Fe）=89.42-90.08, （m＋f）/Si （（atomicity Mg＋atomicity Fe） /atomicity Si）=1.53-1.75 （1.59 in average）, respectively. The mean M/F （atomicity Mg/atomicity Fe） ratio of the rocks is 9.05, which is classified as magnesium enriched-type of ultramafic rocks. The compositional features, depleted in K, Na, Ca, AI and Ti and enriched in Mg#, indicate the characteristics of peridotite originated from a depleted mantle. The rocks have low REE with ∑（1.60-2.68）×10^-6 similar to those of the primitive mantle. The chondrite-normalized REE patterns of all samples show slightly enrichment in LREE, with （Ce/Yb）N 1.03-2.46

关键词： ultramafic rock ophiolite eclogite Sumdo Lhasa block.