Influence of climate and tectonic movements on granite landforms in China     

CHEN Yixin  CUI Zhijiu  YANG Jianqiang 《地理学报》2009,19(5):587-599

Present granite landform characteristics and distribution are the integrated result of climate, tectonics and lithology. Various types of granite landforms in China signify climate zonality and differential vertical movement of earth surface, while published research results on Chinese granite landforms are very rare, especially in international journals. Based on the process analysis of chemical weathering and physical disintegration, four granite landform regions in China are classified according to the present climate regime. On the Tibetan Plateau, the cold and freezing climate induced periglacial landscapes; the northeast region is characterized by physical disintegration and low round mounds are widespread; in the northwest region controlled by arid climate, wind-carved minor landscapes are extremely prominent. The most spectacular granite landscapes in China are presented in southeast as a result of longtime chemical weathering under humid and warm conditions, as well as the differential uplift after Neogene. Correlating the weathering crust in southern China, Tibetan Plateau and India, a possible unified planation surface in Neogene is proposed. With corestones as indicators of original weathering front, the differential uplift extent of dissected planation surfaces can be estimated. At least three landforms implying uplift can be identified in southeastern China, with elevations of 300–400 m, 2000 m and 3600 m above the sea level respectively.  相似文献   

乞盖淖湖湖床垂向渗透系数试验研究   总被引：4，自引：2，他引：2       下载免费PDF全文

尹立河  李瑛  窦妍  崔旭东  黄金廷 《盐湖研究》2009,17(3):23-28

地下水与湖水的转化必须要通过湖床沉积物,因此湖床渗透系数是评价湖水与地下水定量转化关系的基础。以内蒙古伊金霍洛旗乞盖淖湖为例,首先分析了湖床沉积物的颗粒组成,然后利用现场渗透试验方法进行了野外试验,计算了湖床的垂向渗透系数。湖床沉积物粒径分析结果表明,湖床沉积物以粉细沙为主。湖床垂向渗透系数计算结果表明,各测点的平均垂向渗透系数介于0．83～13．59cm／d,表明乞盖淖湖床垂向渗透性能在空间上具有非均质性。该研究为定量计算地下水与湖水的转化关系提供了基础参数。  相似文献   

汶川5.12地震发震机理的数值模拟   总被引：15，自引：10，他引：5  

王连捷  崔军文  周春景  孙东生  王薇  唐哲民  钱华山 《地质力学学报》2009,15(2):105-113

将围岩看成弹性体, 断层看成具有应变软化的弹塑性体, 断层和围岩组成统一的地质介质系统。在给定的地应力、孔隙压力及边界位移的作用下, 应力逐渐积累, 当达到断层强度时, 断层进入塑性状态, 应变随之软化, 应力突然下降, 能量突然释放, 形成地震。根据这个原理, 利用有限差分FLAC软件, 对汶川5.12地震的机理进行了模拟。模拟结果证实:汶川5.12地震是在青藏高原侧向挤压, 四川盆地阻挡, 使龙门山断裂带受到缓慢增加的挤压应力场作用下形成的。计算结果给出了应力降、能量释放量、断层错动量、地震同震位移、震前位移、地震复发周期等重要参数, 结果与野外调查及其它资料给出的数据具有较好的一致性。   相似文献   

雪峰隆起西南缘古应力特征及其石油地质意义     

崔敏  汤良杰  王鹏昊  郭彤楼  路兴斌 《地质力学学报》2009,15(3):289-295

在野外地质调查、平衡剖面分析的基础上, 结合区域构造演化, 采用岩石声发射法对雪峰隆起西南缘的最大古应力进行了恢复, 并探讨了古应力大小与油气成藏破坏的关系。研究结果表明, 研究区共经历了5期不同强度的重要构造变革运动。在早古生代末期和印支期构造运动较弱, 声发射法的测量表明古应力值分别为13.3 MPa和24 MPa, 对应于麻江古油藏的主要成藏期。构造运动次数较多或者古应力值较大的时期, 主要对应于麻江古油藏储集层的发育期和油藏大规模破坏期。晚古生代末期构造活动次数较少, 但恢复地古应力值较大, 为92.6 MPa; 燕山期和喜马拉雅期经历了多期构造活动, 恢复地古应力值为23.3~74.4 MPa。   相似文献   

Present and Late Pleistocene equilibrium line altitudes in Changbai Mountains, Northeast China     

ZHANG Wei  CUI Zhijiu  YAN Ling 《地理学报》2009,19(3):373-383

According to the glacial landforms and deposits with the optically stimulated luminescence (OSL) dating results, two glacial stages of the last glacial cycle (LGC) and Late Glacial were identified. The Late Glacial stage (Meteorological Station glacier advance) took place about 11 ka (11.3±1.2 ka), and the last glacial maximum (LGM), named Black Wind Mouth glacier advance, occurred at 20 ka (20.0±2.1 ka). Based on the Ohmura’s formula in which there is a relationship between summer (JJA) atmospheric temperature (T) and the annual precipitation (P) at ELA, the present theoretical equilibrium line altitude (ELAt) in Changbai Mountains was 3380±100 m. Six methods of accumulation–area ratio (AAR), maximum elevation of lateral moraines (MELM), toe–to headwall altitude ratios (THAR), the terminal to summit altitudinal (TSAM), the altitude of cirque floor (CF), and the terminal to average elevation of the catchment area (Hofer) were used for calculation of the former ELAs in different stages. These methods provided the ELA for a range of 2250–2383 m with an average value of 2320±20 m during the LGM, which is 200 m higher than the value of previous investigation. The snowlines during the Late Glacial are 2490 m on northern slope, and 2440 m on western slope. The results show that the snowline on northern slope is 50 m higher than that on western slope during the Late Glacial, and the average snowline is 2465m. The ELA △ values were more than 1000 m during the LGM, and about 920 m lower than now during the Late Glacial stage respectively. Compared with Taiwanese and Japanese mountains in East Asia during the LGM, the effect of the uplift on ELA in Changbai Mountains during the glaciations (i.e. 20 m uplift in the LGM and 11 m in the Late Glacial) is not obvious.  相似文献   

地热开采对聊古1井地下流体动态的影响及其对策   总被引：2，自引：0，他引：2       下载免费PDF全文

王华  王伟  李月强  陈其锋  魏汝庆  赵杰锋  冯恩国  崔娜 《地震地质》2009,31(3):515

简要介绍了聊古1井井区的水文地质条件,全面调查了聊城地震水化站外围地热资源开发的现状,在此基础上分析了地热开发对地震地下流体观测及其动态的影响。结果表明,井区周围地热开发导致聊古1井断流,引起了各项动态异常的出现;该井区碳酸盐岩岩溶性水的开采对地下流体观测及其动态产生影响,特别是冬季供暖期的开采对地下水物理动态产生严重干扰。为了消除或减弱这种影响,通过改造井口装置实现人工自流的方法,保证了各项观测,而且部分测项的观测条件得到改善,多数测项的动态资料可连续,只有少数测项动态受到较大影响,井口改造取得了一定实效。然而,根本的出路还应是保护观测系统,停止同层地热开发  相似文献   

2000年姚安M_S6.5地震震源破裂过程研究     

毛燕  崔建文  刘娜  李君  张潜 《地震研究》2009,32(4)

利用从IRIS上获取的11个台站震相清晰的P波波形记录资料对2000年姚安MS6.5地震的震源破裂过程进行了反演,结果表明:(1)地震破裂持续时间为5.6s,破裂主要集中在破裂开始0.2s后的时间段内,由两次2s多的破裂组成,而且后一次破裂的强度超过了前一次;(2)静态滑动位移和应力降分布图均显示存在震中区和震中以东区两个变化比较明显的区域,破裂沿北西向断裂进行。  相似文献   

汶川8.0级地震序列活动的分段性研究   总被引：2，自引：0，他引：2  

李志雄  邵志刚  赵翠萍  李圣强  王慧敏  吕梅梅  和平  刘桂平  崔子键 《地震》2009,29(1):26-32

在汶川8.0级地震序列的跟踪研究中, 发现汶川地震序列具有明显的空间分段活动特点。 根据对汶川地震余震序列的部分测震学指标计算, 结果表明, 汶川地震序列可能是由以绵竹为界, 其西南段的汶川主-余震序列和绵竹北东段的北川－青川6级震群地震序列组成, 汶川地震可能具有龙门山活动构造的继承性运动特点。  相似文献   

Effects of precipitation and landuse on runoff during the past 50 years in a typical watershed in the Loess Plateau, China   总被引：2，自引：0，他引：2  

Huaxing BI  Bin LIU  Jie WU  Lei YUN  Zhihan CHEN  Zhewei CUI Prof. in hydrology  College of soil  water conservation  Box  Beijing Forestry University  Qinghua East Road  Haidian District  Beijing  China  Researcher in hydrology  Xifeng station of soil  water conservation  Xifeng  Gansu Province  China Graduate Assis. 《国际泥沙研究》2009,24(3):352-364

In the past century, great progress has been made worldwide in our understanding of forest-water relationship. The successful forestation programs implemented in China-which have improved the ecological environmental conditions-have gained the attention of many researchers and highlighted the relationship between forestation and water yields. The arid and semi-arid Loess Plateau has received attention from water engineers and eco-hydrological researchers in China because of a shortage in water resources. We selected one of the oldest stations conducting soil and water conservation experiments, the Xifeng soil and water conservation station, and chose the Nanxiaohe catchment and its paired catchments （Yangjiagou catchment and Dongzhuanggou catchment） as our research areas. Trends in precipitation, air temperature, streamflow over the past 50 years, and the effect of changing land use on streamflow were analyzed. The Mann-Kendall test showed that precipitation had a negative trend （downward trend）, whereas air temperature showed a positive trend （upward trend） from the past to present in the Nanxiaohe catchment. However, the trends seen in precipitation, air temperature did not contain any ＂jumping points.＂ The paired catchment approach is used to detect the effects of land cover change on hydrology in the Yangjiagou and the contrast catchment, i.e., Dongzhuanggou catchment in our study. The results showed a large change in land use in the Yangjiagou catchment from 1954 to 2008. An increase in forested land （from 0% to 40.08% from 1954 to 2008） and a reduction of bare land （from 51.26% to 5.50% from 1954 to 2008） accounted for a large part of the change in land use. However, the land use changed little in the contrast catchment. The comparison of streamfiow in the paired catchments showed that forestation reduced streamflow by 49.63% （or 6.5 mm） each year.  相似文献   

昆仑8.1级地震同震形变特征及其对响应地震活动的制约机制          下载免费PDF全文

陈兵  崔笃信  王庆良  张晓亮  王文萍  薛富平  王敏 《地球物理学进展》2009,24(4):1204-1212

本文定义”响应地震”的概念统一表述昆仑山口西8.1级地震所引发的主破裂两侧临近构造及部分块体边界上的显著地震活动.其主体活动区域集中在昆仑地震主破裂的西南侧和东北侧及祁连山断裂.同时,地壳运动在主破裂北侧的甘青块体中西部出现与背景运动场反向的特征性变化,祁连山断裂出现应变弱化.弹性位移-应力阶跃模型模拟结果显示,昆仑地震造成其东北侧甘青块体中西部地壳运动的反向运动(相对背景场).并形成东北部和西南部两个体应变张性区域,绝大部分响应地震都发生在应变张性区中和块体张性边界上.这种强烈挤压剪切背景中出现的相对松弛状态与昆仑地震后青藏块体地震弱活动背景中出现的显著活跃的响应地震活动的正相关性可能反映了断层约束状态的相对减弱对滑动的触发作用.说明在考虑地震发生条件时,不能只着眼于应力场是否增强,断层摩擦强度,或更广义地说,构造约束条件的变化也是一个不容忽视的重要因素.  相似文献