准噶尔内陆盆地沉积物通量变化与周边山体隆升          下载免费PDF全文

王龙樟 《沉积与特提斯地质》1996,16(3):39-46

本文根据地层厚度资料，对准噶尔内陆盆地晚二叠世－早第三世的沉积物通量进行了计算。计算结果表明，晚二叠世的沉积物通量（１８．２９７×１０６ｍ３／ａ）比中生代－早第三纪（１．７３５×１０６－３．１４２×１０６ｍ３／ａ）高出近一个数量级，因而推测晚二叠世是内陆盆地的主要成盆期。对盆地不同部位的沉积物通量进行比较发现，盆地南部沉积物通量最高，西北部次之．东北部最低。因此，古天山山系的升隆作用较之其他山系更为强烈，可能与其频繁的升降历史和塔里木陆块的推挤作用有关。  相似文献   

青藏高原隆升机制新模式   总被引：25，自引：4，他引：21  

李德威 《地球科学》2003,28(6):593-600

作为创建大陆动力学理论体系的最佳野外实验室的青藏高原, 涉及当代固体地球科学前沿和热点的许多重大科学问题.迄今为止, 包括板块构造在内的众多模式不能合理地解释青藏高原重要的地质和地球物理现象.本文从下地壳与中上地壳、造山带与沉积盆地的耦合作用出发, 对青藏高原及邻区进行分尺度、分层块、分阶段的构造解析, 提出青藏高原隆升的下地壳层流构造模式, 认为青藏高原地壳增厚和构造隆升是晚新生代由于锡瓦利克盆地、塔里木盆地和四川盆地下地壳的热软化岩石大量流向青藏高原造成的.   相似文献   

地球介质的非定常参数黏弹模型   总被引：3，自引：0，他引：3       下载免费PDF全文

施行觉  李成波  Adnan Aydin  黄建华  赵闯 《地球物理学报》2009,52(1):50-56

用开尔文黏弹模型对实验蠕变曲线和冰后期地面抬升观测曲线进行反演,得到相关的黏弹参数,发现所有的黏弹参数都随实验（或观测）时间长度发生有规律的变化, 表明黏弹参数是实验(或观测)时间的函数.在此基础上提出非定常参数的黏弹模型,将通常采用的剪切模量μ₂、弛豫时间τ 和黏度η 相应地从常数修正为时间的函数μ₂(t)、τ(t) 和η（t）,检验表明修正后的开尔文模型可以更好地符合实测蠕变曲线.用修正后的μ₂(t)对软流层的黏度进行估算,其值约为4.6×10²⁰ Pa·s.  相似文献   

IMPACT OF UPLIFT OF TIBETAN PLATEAU AND CHANGE OF LAND-OCEAN DISTRIBUTION ON CLIMATE OVER ASIA^*          下载免费PDF全文

CHEN Longxun  LIU Jiping  ZHOU Xiuji  WANG Pinxian 《Acta Meteorologica Sinica》2000,14(4):459-474

Using an improved CCM1/NCAR climate dynamic model and a combination distribution of land-ocean-vegetation during 40-50 MaBP,a series of numerical experiments representing different stages of the Tibetan Plateau uplifting and different land-ocean distributions are designed to discuss the influence of the Plateau uplifting and land-ocean distribution variation on Asian climate change.It is shown that Tibetan Plateau uplifting can firstly increase the precipitation in China during the period from initial uplift to half height of modern Tibetan Plateau and then decrease the rainfall during the time from the half height to the present plateau. At the same time.the uplifting can reduce surface air temperature over China.Besides.the effects of the uplift and land-ocean distribution change on the variation of winter and summer Asian monsoon circulation are also discussed.  相似文献   

RELATION BETWEEN RAPID UPLIFTING AND GRAVITATIONAL EQUILIBRIUM ,TECTONICS AND THERMODYNAMIC EFFECT IN QINGHAI—TIBET PLATEAU     

Chi Xiaoguo  Li Cai  Liu Shen  Yang Rihong 《地学前缘》2000,(Z1)

RELATION BETWEEN RAPID UPLIFTING AND GRAVITATIONAL EQUILIBRIUM ,TECTONICS AND THERMODYNAMIC EFFECT IN QINGHAI—TIBET PLATEAU  相似文献   

晋江龙湖湖盆古凹陷内古河流形成与消亡及与地震关系     

徐起浩  施建生 《海洋地质与第四纪地质》2012,(2):53-63

根据野外调查及龙湖湖内和沿岸共78个钻孔岩心揭示的龙湖及沿岸混合花岗岩及其风化土、残坡积层和晚更新世以来的沉积层展布,分析了龙湖成湖前的凹陷和发育在凹陷内的古河流环境。研究发现龙湖湖盆内下游古河床相对邻近上游河床被大幅度抬升达3m余。龙湖的最早湖相沉积年龄为2 430±90aBP,其年龄落在导致古森林更深沉没于海的深沪湾晚全新世强古地震的时间范围内,认为龙湖的形成可能与2 430aBP左右深沪湾大地震,导致控制深沪湾陆地地堑的衙口—氵丙州断裂西北侧地块翘起掀升,使得湖盆凹陷内下游古河床被快速抬升,古河流被堵塞有关。龙湖是地震断塞湖,不同于断陷湖,是向斜坳陷湖的又一种构造湖。研究得出龙湖成湖前的古河流约在7 000aBP开始形成,这正是导致深沪湾古森林首次沉没于海的深沪湾早全新世强古地震大致年龄,结合古河床形成前的凹陷形态,认为龙湖湖盆内古河流的形成可能与7 000aBP左右深沪湾大地震导致龙湖地区环境改变有关。  相似文献   

Uplift of deck or footings in bridges with distributed mass subjected to transverse earthquake          下载免费PDF全文

Michael N. Fardis 《地震工程与结构动力学》2015,44(15):2755-2773

The eigenvalue problem is analytically formulated in symmetric bridges with distributed mass and moment of inertia under transverse earthquake. The piers are elastically supported on the ground. The deck is monolithically connected to one or two piers for all degrees of freedom and restrained or transversely free at the abutments. The characteristic equation, symmetric normal modes, modal participation factors, and participating mass ratios are given analytically. The problem is expressed in terms of few dimensionless parameters: (i) the radius of gyration of the deck mass divided by the pier height; (ii) the ratio of the rotational stiffness of a footing to that of the pier at the base; (iii) the ratio of flexural stiffness of the outer spans to those of the pier; (iv) the ratio of torsional stiffness of side spans to the rotational stiffness of the pier top; (v) for two piers, the side‐to‐central‐span ratio. Modal response spectrum analysis gives the moment at the base of the footings and the torque in the deck at its supports on the abutments as ratios to the values at incipient uplifting from the ground or the bearings. The peak ground acceleration of the motion at the onset of either one of these two types of nonlinearity is depicted as a function of the dimensionless parameters and the fundamental period of an elastic deck supported only at the abutments, or of a rigid deck on piers fixed against rotation at top and bottom. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献