珠江口盆地晚侏罗世中基性火山岩的岩石成因与构造意义：来自年代学和地球化学的约束     

刘杰  侯明才  王菲  牛胜利  梁杰  熊富浩  陈安清  钟灵  冷杰 《地质学报》2023,97(2):364-375

位于南海北部陆缘的珠江口盆地发育中生代岩浆岩,记录了古太平洋板片俯冲消亡的动力学过程。本项研究以钻井揭露的晚侏罗世火山岩为研究对象,开展系统的岩石学、岩相学、年代学和地球化学研究,探讨其成因机制和动力学背景。岩石学及地球化学分析显示,这套火山岩由玄武岩、玄武安山岩、安山岩和粗面安山岩组成。LA-ICP-MS锆石U-Pb年代学分析表明,玄武安山岩的结晶年龄为154.0±3.2 Ma。岩石的SiO₂含量为49.54%～58.22%,K₂O含量为0.71%～3.00%,MgO含量为5.29%～11.05%,Mg^#值介于52～66之间,属于高钾钙碱性系列中基性火山岩。岩石的轻重稀土元素分馏明显,(La/Yb)_N比值为5.00～6.93,且具有轻微的铕负异常,δEu值为0.73～1.04。样品显著富集大离子亲石元素Rb、Ba、Th和U等,相对亏损高场强元素Nb、Ta、Ti和P等。岩石成因分析表明,晚侏罗世中基性火山岩主要起源于受俯冲板片流体交代的富集岩石圈地幔熔融,且岩浆经历了辉石、角闪石等矿物的分离结晶。综...  相似文献   

THE TYPES OF LAKE IN SONGNEN PLAIN AND THEIR REGIONAL CHARACTER     

Jin-fu Lu  Dong-mei Jie  Zhi-min Li  Xue-tian Leng 《中国地理科学(英文版)》2000,10(4):366-370

The lake groups in the Songnen Plain are low plain lake groups, which are located in the temperate semihumid area in China. They are characterized by small area, shallow basin, thick density and various types. In the try for classifying comprehensively the lake groups, a classification system is developed based on three main factors, i.e. forming cause, water quantity and water quality. The most internal character can be concisely grasped through three principal indexes and three auxiliary indexes of three main factors. A sample of complicated changeable path is put forward for further analyzing and outlining these basic types, in the meantime, it’s linking up easily with the classification system of the single factor. According to the regional environment, the regional differences of the type composition and the principal types, the lake groups in the Songnen Plain can be divided into 6 sub-regions. Foundation item: Under the auspices of the National Natural Science Foundation of China(49671077). Biography: LU Jin-fu (1938–), male, professor. His research interest includes paleo-environment in the Quaternary.  相似文献   

Coupling fuzzy clustering and cellular automata based on local maxima of development potential to model urban emergence and expansion in economic development zones   总被引：1，自引：0，他引：1  

Xun Liang  Guangliang Chen  Jiye Leng  Youyue Wen  Guangzhao Chen 《International journal of geographical information science》2020,34(10):1930-1952

ABSTRACT

Modeling urban growth in Economic development zones (EDZs) can help planners determine appropriate land policies for these regions. However, sometimes EDZs are established in remote areas outside of central cities that have no historical urban areas. Existing models are unable to simulate the emergence of urban areas without historical urban land in EDZs. In this study, a cellular automaton (CA) model based on fuzzy clustering is developed to address this issue. This model is implemented by coupling an unsupervised classification method and a modified CA model with an urban emergence mechanism based on local maxima. Through an analysis of the planning policies and existing infrastructure, the proposed model can detect the potential start zones and simulate the trajectory of urban growth independent of the historical urban land use. The method is validated in the urban emergence simulation of the Taiping Bay development zone in Dalian, China from 2013 to 2019. The proposed model is applied to future simulation in 2019–2030. The results demonstrate that the proposed model can be used to predict urban emergence and generate the possible future urban form, which will assist planners in determining the urban layout and controlling urban growth in EDZs.  相似文献   

Holocene climate change in the eastern Mediterranean region: a comparison of stable isotope and pollen data from Lake Gölhisar,southwest Turkey     

Warren J. Eastwood  Melanie J. Leng  Neil Roberts  Basil Davis 《第四纪科学杂志》2007,22(4):327-341

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THE ARCHIPELAGIC CONCEPT AND ITS IMPACT ON SOUTHEAST ASIA     

Lee Yong Leng  M.A.  Ph.D. 《Singapore journal of tropical geography》1983,4(1):34-39

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High‐resolution diatom δ18O records,from the last 150 years,reflecting changes in amount of winter precipitation in two sub‐Arctic high‐altitude lakes in the Swedish Scandes     

Christina E. Jonsson  Gunhild C. Rosqvist  Melanie J. Leng  Christian Bigler  Jonas Bergman  Päivi Kaislahti Tillman  Hilary J. Sloane 《第四纪科学杂志》2010,25(6):918-930

Waters from high‐altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high‐altitude lakes have lake water isotopic compositions (δ¹⁸O_lake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water δ¹⁸O. Here we compare two high‐resolution δ¹⁸O_diatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900–1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ¹⁸O_diatom as decreasing trends. Lowest δ¹⁸O_diatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the δ¹⁸O_diatom signal in these sub‐Arctic high‐altitude lakes with short residence times has been changes in amount of winter precipitation and that δ¹⁸O_diatom derived from high‐altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Fully nonlinear simulations of wave resonance by an array of cylinders in vertical motions     

黄豪彩  王赤忠  冷建兴 《中国海洋工程》2013,27(1):87-98

The finite element method(FEM) is employed to analyze the resonant oscillations of the liquid confined within multiple or an array of floating bodies with fully nonlinear boundary conditions on the free surface and the body surface in two dimensions.The velocity potentials at each time step are obtained through the FEM with 8-node quadratic shape functions.The finite element linear system is solved by the conjugate gradient(CG) method with a symmetric successive overelaxlation(SSOR) preconditioner.The waves at the open boundary are absorbed by the combination of the damping zone method and the Sommerfeld-Orlanski equation.Numerical examples are given by an array of floating wedgeshaped cylinders and rectangular cylinders.Results are provided for heave motions including wave elevations,profiles and hydrodynamic forces.Comparisons are made in several cases with the results obtained from the second order solution in the time domain.It is found that the wave amplitude in the middle region of the array is larger than those in other places,and the hydrodynamic force on a cylinder increases with the cylinder closing to the middle of the array.  相似文献   

A geological constraint on relative sea level in Marine Isotope Stage 3 in the Larsemann Hills, Lambert Glacier region, East Antarctica (31 366–33 228 cal yr BP)     

Dominic A. Hodgson  Elie Verleyen  Wim Vyverman  Koen Sabbe  Melanie J. Leng  Matthew D. Pickering  Brendan J. Keely 《Quaternary Science Reviews》2009,28(25-26):2689-2696

In this paper we present geological evidence from the Larsemann Hills (Lambert Glacier – Amery Ice Shelf region, East Antarctica) of marine sediments at an altitude of c. 8 m a.s.l., as revealed by diatom, pigment and geochemical proxies in a lake sediment core. The sediments yielded radiocarbon dates between c. 26 650 and 28 750 ¹⁴C yr BP (31 366–33 228 cal yr BP). This information can be used to constrain relative sea level adjacent to the Lambert Glacier at the end of Marine Isotope Stage 3. These data are compared with the age and altitude of Marine Isotope Stage 3 marine deposits elsewhere in East Antarctica and discussed with reference to late Quaternary ice sheet history and eustatic sea-level change.  相似文献   

地震数据规则化应用效果分析     

冷广升 《中国煤炭地质》2010,(2):49-53

传统面元规则化处理主要采用静态和动态面规则化等技术,但因丢道或借道原因,仍存在覆盖次数不均匀或振幅信息误差。煤炭地震勘探一般具有覆盖次数低、面元小的特点,借鉴同济大学辛可锋利用DMO实现三维数据规则化的方法和Biondi提出的三维叠前地震数据方位角校正方法,从方位角校正的角度入手,利用DMO和DMO-1相结合的处理流程对煤炭地震数据进行规则化。某煤矿区的地震数据规则化处理效果证实,在施工条件复杂、测线方向变化频繁、观测系统规则性很差的勘探区,对采集数据进行规则化处理,可使CMP的空间位置趋于规则分布,缺失的偏移距得到一定的弥补,更符合数据处理对观测系统的要求。处理后的数据既保持了原来的振幅特征,同时也提高了时间剖面的信噪比,数据规则化处理效果明显。  相似文献   

武陵山经济协作区空间协调发展程度评价   总被引：2，自引：1，他引：1  

冷志明 《地理研究》2012,31(3):521-533

与以往区域协调发展程度评价研究不同,本文基于协调发展概念强调经济联系、区域差异、动态收敛和可持续发展的本质特点,构建空间（区域）评价体系,分别从基本公共服务均等化程度、区际一体化程度、区际人均GDP均等化程度、城乡人均消费水平差异程度四个方面评价武陵山经济协作区空间协调发展程度。评价结果显示,2001～2009年间,武...  相似文献