Climate variability in the Salawusu River valley of the Ordos Plateau (Inner Mongolia,China) during Marine Isotope Stage 3   总被引：1，自引：0，他引：1  

Xiaohao Wen  Baosheng Li  Yanming Zheng  David Dian Zhang  Jianping Ye 《第四纪科学杂志》2009,24(1):61-74

Fluctuations in climatic proxies of the Milanggouwan section in the Salawusu River valley of the Ordos Plateau (Inner Mongolia, China) during Marine Isotope stage 3 (MIS 3) coincide well with sedimentary cycles for palaeo‐mobile dune sands alternating with fluvial–lacustrine facies and palaeosols. We compared the palaeo‐mobile dune sands with modern mobile dune sands (products of a cold and dry climate dominated by the East Asian winter monsoon), whereas the fluvial–lacustrine facies and palaeosols were controlled by a wet–warm climate similar to that of the East Asian summer monsoon. The MIS 3 climate of the Salawusu River valley appears to have experienced at least nine wet–warm and ten cold–dry fluctuations, divided into five stages: MIS 3e (58 900–49500 yr BP), MIS 3d (49 500–40 700 yr BP), MIS 3c (40 700–36 900 yr BP), MIS 3b (36 900–27 000 yr BP) and MIS 3a (27 000–22 300 yr BP). The 19 cold–warm climatic fluctuations corresponded roughly to the GRIP and Guliyan records, and with fluctuations in the North Atlantic climate. Notable peaks in the spectral analysis occurred at 19 500 yr, 1020 yr, 640 yr and 500 yr. Our results show that the millennial–centennial climate was closely related to the relative strengths of East Asian monsoons, which are controlled by the North Atlantic thermohaline circulation, and which is also closely linked to the Sun's precession period. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

新疆库地南苏盖提力克晚志留世花岗岩锆石U-Pb年龄、地球化学特征及大地构造意义     

专少鹏  白春东  毛志芳  李典  张新征  陈圆圆  连青 《地质力学学报》2018,24(5):661-669

西昆仑地区早古生代原特提斯洋的后碰撞阶段划分存在分歧,通过对库地蛇绿岩南侧苏盖提力克花岗岩开展区域地质调查、岩石学、地球化学、锆石U-Pb年代学等方面研究,从而为原特提斯洋构造演化及闭合时限提供地质依据。研究表明,苏盖提力克花岗岩锆石U-Pb年龄（LA-ICP-MS）为（422.5±2.5）Ma,属于晚志留世岩浆活动产物。苏盖提力克花岗岩含有典型矿物白云母,A/CNK=1.07~1.11,刚玉分子含量为1.07%~1.56%,属于S型花岗岩。地球化学上,该岩体富硅、碱,贫钙、镁,富K、Rb、Nb、Th,贫Sr、Ti、P,Rb/Sr比值高;结合区域地质背景及地球化学特征综合分析表明,苏盖提力克花岗岩是原特提斯洋闭合后碰撞阶段的产物,因而晚志留世是原特提斯洋由消减闭合到陆陆碰撞—碰撞后伸展转换时期。   相似文献   

雅鲁藏布江航磁异常带性质及其意义   总被引：5，自引：6，他引：5  

姚正煦  周伏洪  薛典军  刘振军  张永军 《物探与化探》2001,25(4):241-252

航磁概查发现雅鲁藏布江航磁异常带东西相连长达1400km,它由北、南2条线性异常带构成,并认为它由沿雅鲁藏布江缝合带侵位的北、南2条蛇绿岩带引起,且以北带为主,即雅鲁藏布江缝合带是由2条蛇绿岩带组成,而不是过去地学界所认同的一条。航磁异常带实质上是雅鲁藏布江缝合带存在的客观反映,不仅为识别缝合带提供了比较典型的磁场模式,也为探讨新特提斯洋演化、可能存在2次开合过程,提供了新的依据。  相似文献   

Study of Sediments in the Yutian-Hotan Oasis, South Xinjiang, China   总被引：2，自引：0，他引：2  

LI Baosheng  David Dian ZHANG  ZHOU Xingjia  ZHU Feng  YUAN Baoyin  MU Guijin  LI Sen  YAN Mancun  JIN Heling  GAO Quanzhou  SUN Wu 《《地质学报》英文版》2002,76(2):221-228

Based on investigation of sediments in the Yutian-Hotan Oasis at the southern margin of the Tarim basin, 14C ages and grain-size and chemical element analyses, the following views are put forward in this paper.(1) Sediments in the Yutian-Hotan Oasis are composed chiefly of "oasis soil", similar to the recent oasis soil, i.e. brown desert soil, which was formed due to pedogenesis after aeolian sand (sandy loam) and dust (loess) of 3.32-6.64 were deposited.(2) The ancient Yutian-Hotan Oasis represented by oasis soil was formed at 13000 a B.P. During the cold period of the past 13000 years, this region is characterized mainly by accumulation of sand and dust storms, and sandy oasis soil was developed in this region due to pedogenesis in an oasis environment; during the warm period, dust falls predominated along with certain current concomitants (lacustrine facies), and silty oasis soil was formed by pedogenesis. Owing to fluctuations of cold and warm climates since 13000 a B.P., sandy oasis soil was deposi  相似文献   

青藏高原的大气CO_2含量、岩溶溶蚀速率及现代岩溶微地貌   总被引：8，自引：0，他引：8  

章典  师长兴 《地质学报》2002,76(4):566-570

青藏高原是世界上最高、最大和最年青的高原。按照气候地貌学的观点,其干燥和寒冷的气候条件不利于岩溶地貌的发育。笔者在青藏高原上已发现了广泛分布的岩溶微形态。笔者用国际通用的石灰岩圆形切片,在西藏三个不同地点进行了12年的野外溶蚀试验,揭示出青藏高原的岩溶溶蚀速率是全世界最低的,在土层中还产生沉淀现象。通过在青藏高原不同高程上测量大气中CO_2分压,发现P_(CO_2)随海拔高度的增加而降低。在土壤、沉积物和岩石裂隙中的P_(CO_2)也呈现同样的变化趋势。由于CO_2含量直接影响天然水的溶蚀能力,因此可以断定低CO_2浓度是造成青藏高原上现代岩溶过程微弱的重要原因之一。其他主要原因包括干旱和寒冷气候条件。通过对不同微地貌上溶蚀速率的计算和形态分析,可以认为,分布于高原面上的所有岩溶微形态中,现代发育的岩溶微地貌形态仅仅是那些与生物岩溶过程有关的溶痕,其他岩溶微地貌形态可能是全新世温暖期的产物。  相似文献   

当代俄罗斯经济区划研究   总被引：1，自引：0，他引：1  

王殿华 《世界地理研究》2004,13(3):37-42

前苏联是世界最早研究经济区并进行经济区划实践的国家。在当代俄罗斯市场经济的转型时期，其经济区划具有新的背景、结构和原则。随着俄罗斯集权化的巩固和联邦化的发展，如何在全国范围内合理布局生产力，改善联邦各主体原有的经济部门和地域结构，使不同水平的区域综合发展，并表现其鲜明的市场专业化水平，进行科学的经济区划是俄罗斯经济地理所面临的主要任务。本文通过对俄罗斯经济区划的历史回顾及现状分析，提出了其区域发展的现存问题及解决措施。  相似文献   

数学变换方法在地震勘探中的应用     

刘洋  王典  刘财 《吉林大学学报(地球科学版)》2005,(Z1)

数学变换是地震勘探资料处理方法中的重要手段之一,从数学模型的求解到地震数据压缩的很多方面都离不开数学变换。着重概述了现今地震勘探方法中几种常用数学变换的基本原理及方法,包括傅立叶变换、小波变换、K-L变换及R adon变换等,并介绍了各种方法在地震勘探领域的应用及发展趋势。  相似文献   

Case 27 thermal infrared anomaly precursor of impending earthquakes     

Zu-ji Qiang  Xiu-deng Xu  Chang-gong Dian 《Pure and Applied Geophysics》1997,149(1):159-171

People have already recognized the temperature increase anomaly before earthquakes, and studies have been made on this phenomenon (Wu, 1980;Wu et al., 1982;Geng, 1985). With the method of fixed-point network observation, only the timing temperature data limited to some sites can be obtained instead of dynamic evolution data of the temperature in a large area within the seismogenic range. However, it is advantageous to use the thermal infrared (IR) radiation measured by Meteosat to detect the ground temperature, because of the data accuracy, large area coverage, large amount of information, and the capability of capturing the time-space dynamic variation of the temperature increase before earthquakes. However relevant works on the relationship of the thermal IR anomaly measured by Meteosat to seismic activity are only found published in the Soviet Union (Gornuy et al., 1988). The authors used the thermal IR anomaly measured by Meteosat to monitor and tried to predict the earthquake of October 18, 1989 in Datong, Shanxi Province and other shocks, and obtained preliminary ideas and methods for carrying out predictions in this way.  相似文献   

贵州喀斯特洞穴的气象特征和气候分带研究   总被引：2，自引：2，他引：2  

章典 《中国岩溶》1985,(Z1):140-148

<正>洞穴气象和气候学的研究对象是洞穴大气变量以及这些变量在洞穴不同地带表现出的不同特征。在喀斯特理论的研究中,它们主要应用在洞穴沉积,溶蚀等理论上。在洞穴学的研究领域中,它们的应用更为广泛。 本文在对贵州一些洞穴三年多的气象观测的基础上,初步研究了贵州洞穴的气象和气候分带问题。这些洞穴大多处于贵州中部地区,海拔高度在800—1500米之间,年平均温度14—17℃。除少数洞穴由于游览造成人为干扰外,大多保持原始环境。必须指出,除了少数短期和白昼观测外,其余大多气象观测是季节性的。因此,本文还缺乏对洞外气候短时期变化与洞内气候的关系作进一步的讨论,总之,下述问题的研究是粗略的,作者希望有更进一步的讨论。  相似文献   

Phases of Environmental Evolution Indicated by Primary Chemical Elements and Paleontological Records in the Upper Pleistocene-Holocene Series for the Salawusu River Valley, China   总被引：4，自引：0，他引：4       下载免费PDF全文

LI Baosheng WEN Xiaohao QIU Shifan David Dian ZHANG DU Shuhuan CHEN Deniu OU Xianjiao NIU Dongfeng 《《地质学报》英文版》2007,81(4):555-565

Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the MUanggouwan section in China＇s Salawnsu River valley into six segments： MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6. The boundary ages for MGS1 （the Dishaogouwan and Dagouwan Formations）, MGS2 （the upper Chengchuan Formation）, MGS3 （the middle Chengchuan Formation）, MGS4 （the lower Chengchuan Formation）, MGS5 （most strata of the Salawusu Formation） and MGS6 （the bottom of the Salawusu Formation and the top of the Lishi Formation） correspond to those of MIS1, MIS2, MIS3, MIS4, MISS and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments （MGS5a, MGS5b, MGS5c, MGS5d and MGS5e） and the boundary ages of these subsegments correspond to those of MISSa, MISSb, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers, and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate （and particularly in the East Asian monsoon） during the glacial and interglacial periods.  相似文献