首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
稻田氮磷径流流失模型研究进展   总被引:1,自引:0,他引:1  
黄微尘  周丰  梁浩  陈磊 《湖泊科学》2021,33(2):336-348
水稻是全球最重要的粮食作物,但种植过程中不合理的水肥管理引起了稻田氮磷径流流失,对邻近水体造成污染风险.稻田氮磷径流流失模型是理解区域水体污染排放时空特征和评估水污染风险的有效手段.论文阐述了稻田氮磷径流流失的发生机制和关键过程,梳理了统计经验模型、物理机理模型、水文过程模型和生态系统模型的研发历程.结果表明,当前模型缺乏水—土—气界面过程的有效参数化,基于高分辨率、多年多站点、全通量的模型参数的合理化,以及区域尺度农艺管理(种植制度、施肥制度、灌排制度)和田—沟—塘联合调控措施(分布、规模、运行规则)的模块化,造成了稻田氮磷径流流失的不确定性.同时,提出了面向稻田氮磷循环的高分辨率全通量观测网络建设、农艺管理与调控措施的区域数据集研发、模型开发与先进技术手段的集成与融合、稻田—氮—磷—水耦合的多模型集合等,为稻田氮磷径流流失模型的改进、农艺管理措施的优化以及气候智能型稻田的建设提供科学依据.  相似文献   

2.
China has achieved much during recent years in the area of lithospheric physics research and promoted the development of the geosciences (Teng, 2004). However, in the 21^st century, national needs and policy challenges the science of lithospheric physics. I suggest a general analysis, research, and development direction for lithospheric physics and point out clearly the content, core problems, and key scientific problems in this field. The realization of the earth and the discovery of the basic mechanisms of mountains, basins, minerals, and natural disasters depend basically on high-resolution observations of geophysics, the delineation of the fine structure of crust and mantle (2D and 3D) inside the lithosphere, substance and energy exchanges in the deep earth, the process of deep physical, mechanical, and chemical actions, and deep dynamical response. Therefore, geophysics should be the pioneer in the geosciences field in the first half of the 21^st century. I end with an analysis and discussion of some problems and difficulties in the research of lithospheric physics.  相似文献   

3.
中国多年来在岩石圈物理学研究中已取得了一系列的重要成果,并促进了中国地球科学的发展。然而在这21世纪之际,基于国家战略需求和自主创新的方针对岩石圈物理学提出了新的挑战。本文在这样的思维前提下对岩石圈物理学的科学内涵和发展导向进行了较全面的分析、研究和思考,并明确指出当今在这一学科领域应该做些什么,核心问题是什么,又存在哪些关键性的科学问题。研究结果提出,高精度的地球物理场观测与岩石圈内壳、幔精细结构(2维和3维)的刻划;在地球内部力系作用下,深部物质和能量的交换;深部物质运移的物理-力学-化学作用过程及深层动力学响应乃是深化对地球本体的认识和揭示成山、成盆、成岩、成矿和成灾的根本机理所在。为此,在本世纪的上、中叶,在地球科学领域中地球物理学研究必为先导。本文最后对岩石圈物理研究中尚存在的一些问题和困惑进行了分析和讨论。  相似文献   

4.
为识别表层沉积物重金属的来源以及量化源贡献,选取鄱阳湖丰水期表层沉积物为研究对象,测定14种重金属(V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Cd、Sb、W、Pb、Hg和As)的含量,分析其污染及空间分布特征,并利用主成分分析法(PCA)和正定矩阵因子分解法(PMF)对沉积物重金属进行源解析.结果表明:除V和Cr外,Cd、Mo、Hg、Cu、Pb、Zn、W、Sr、As、Ni、Co和Sb的平均含量分别为江西省土壤背景值的5.7、2.2、1.9、1.8、1.5、1.5、1.4、1.3、1.3、1.2、1.0和1.0倍; Cd、Hg、Cu、Mo、Pb、Sr和Zn超出江西省土壤背景值的比例相对较高,分别为100%、100%、100%、100%、97%、97%和93%,所有沉积物样品中Cd含量超过农用地土壤污染风险筛选值的比例为51%; V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Sb、W、Pb、Hg和As含量呈未污染至弱污染水平,而Cd含量属于中等污染水平,接近于重污染水平.总体而言,Cd的污染相对较严重.重金属的分布具有显著的区域特征,其中Cr、Cu、Zn、Sr、Pb、Hg和As的空间分布十分相似,表现为在赣江、抚河、信江和饶河入湖口附近区域含量较高,而Co、Ni、Mo和Sb明显在湖区南部、东北部和修水入湖附近这3个区域聚集,Cd和W的空间变异性相对较大,V的含量分布相对较均匀.PCA和PMF解析结果都表明鄱阳湖丰水期表层沉积物重金属受4种来源的共同影响,其中,矿业和工业活动的影响最大,相对贡献率为38%,其次是尾矿和废渣,相对贡献率为28%,再是农业活动,相对贡献率为19%,最后是自然来源的相对贡献率为14%.  相似文献   

5.
We determined the partition coefficients of 19 elements between metallic liquid and silicate liquid at 20 GPa and 2500°C, and between metallic liquid and silicate perovskite at 27 GPa and 2200°C. Remarkable differences were observed in the partitioning behaviors of Si, P, W, Re, and Pb among the silicate liquid, perovskite, and magnesiowüstite coexisting with metallic liquid, reflecting incompatibility of the elements in the silicate or oxide phase. We could not observe any significant difference in the partitioning behaviors of V, Cr, Mn, Co, Ni, and Cu among the phases coexisting with metallic liquid.

Comparison of the present partitioning data with those obtained previously at lower pressure and temperature suggests that the exchange partition coefficients, Kmet/sil, of Co, Ni, Mo, and W decrease, whereas those of V, Cr, and Mn increase and tend to approach unity with increasing pressure and temperature. We also made preliminary experiments to clarify the effect of sulfur on the partitioning behaviors. Sulfur lowers the exchange partition coefficients, Kmet/sil, of Mo and W between metallic liquid and silicate liquid significantly at 20 GPa and 2300°C.

The mantle abundances of Co, Ni, Cu, Mo, and W calculated for the metal-silicate equilibrium model are lower than those of the real mantle, whereas P, K, and Mn are overabundant in the calculated mantle. The discrepancies in the abundances of Co and Ni could be explained by the chemical equilibrium at higher pressure and temperature. Large discrepancies in Mo and W between the calculated and real mantles could be accounted for by the effect of sulfur combined with the effects of pressure and temperature on the chemical equilibrium. The mantle abundances of P, K, and Cu could be accounted for by volatile loss in the nebula, perhaps before accretion of the Earth, combined with the chemical equilibrium at higher pressure and temperature. Thus the observed mantle abundances of P, K, Co, Ni, Cu, Mo, and W may be consistent with a model of sulfur-bearing metal-silicate equilibrium in lower-mantle conditions.  相似文献   


6.
本文在简略论述重庆江北5.2、5.4级地震基础上,介绍了新闻媒介在报道震情灾情、地震趋势的判断、抗震救灾、宣传地震科普知识、消除群众疑虑思想、报道建筑物的抗震能力、预防次生灾害以及对稳定社会、安定人心,减轻地震灾害损失等方面起到的重要作用。  相似文献   

7.
我国多年来在岩石圈物理学研究中已取得了一系列的重要成果,并促进了我国地球科学的发展.然而在这21世纪之际,基于国家战略需求和自主创新的方针对岩石圏物理学是挑战,也是机遇.为此,必须厘定其今后的发展导向,并凝炼出前瞻性、并具有带动性的创新性核心科学问题.本文在这样的思维前提下对岩石圈物理学的科学内涵和发展导向进行了较全面的分析、研究和思考,并明确指出当今在这一学科领域应该做些什么,核心问题是什么,又存在哪些关键性的科学问题.研究结果提出,高精度的地球物理场观测与岩石圏内壳、幔精细结构(2维和3维)的刻划;在地球内部力系作用下,深部物质和能量的交换;深部物质运移的物理—力学—化学作用过程及深层动力学响应乃是深化对地球本体的认识和揭示成山、成盆、成岩、成矿和成灾的根本机理所在.为此,在本世纪的上、中叶,在地球科学领域中地球物理学研究必为先导!本文最后对岩石圈物理研究中尚存在的一些问题及困惑进行了分析和讨论,并提出了有关统一规划和观测仪器与设备的自主研发以及有序进行国际合作等方面的意见.  相似文献   

8.
双相各向异性研究、问题与应用前景   总被引:13,自引:4,他引:9  
地球内部流体的存在和岩石各向异性是地下介质的两大表征,考虑地下流体和介质各向异性问题的双相各向异性理论是当今地震学和地球物理学理论与应用研究的前沿和难题之一。孔隙流体的存在、固体和流体之间的相互作用会弱化或硬化岩石的力学属性,上起声波或弹性声波速度的频散的振幅的衰减,并产生第二类压缩波。裂缝或裂隙的定向分布、岩层的旋性沉积、应力场的定向排列,都会引起传播速度的各向异性、横波发生分裂等重要现象,这些  相似文献   

9.
针对震前灾情难以预估,震后灾情获取缓慢且碎片化,灾情评估误差较大,决策支持不到位,灾情服务缺位等科学问题,综合考虑震前应急准备和灾后应急处置场景,重点研究全时程灾情与决策信息获取和分析手段,震后灾情信息实时汇聚与融合技术,震后基于致死性和易损性相结合的损失综合分析技术,不同区域辅助决策支持要点,面向多用户灾情信息服务产品可视化生成技术,建立灾情推送与信息准实时服务平台及终端,构建基于云架构的智能化、可视化地震应急信息全流程服务平台,开展应急协同服务示范,实现7级以上大地震灾情信息全时程服务。该项目将丰富地震灾情信息获取手段,形成涵盖灾情收集、信息速报、监测预警、分析评估、智能协同和动态发布等地震应急全过程技术平台,提升地震应急信息服务能力,对快速、科学施救具有重要意义。   相似文献   

10.
Improving our ability to detect changes in terrestrial and aquatic systems is a grand challenge in the environmental sciences. In a world experiencing increasingly rapid rates of climate change and ecosystem transformation, our ability to understand and predict how, when, where, and why changes occur is essential for adapting and mitigating human behaviours. In this context, long-term field research infrastructures have a fundamentally important role to play. For northern boreal landscapes, the Krycklan Catchment Study (KCS) has supported monitoring and research aimed at revealing these changes since it was initiated in 1980. Early studies focused on forest regeneration and microclimatic conditions, nutrient balances and forest hydrology, which included monitoring climate variables, water balance components, and stream water chemistry. The research infrastructure has expanded over the years to encompass a 6790 ha catchment, which currently includes 11 gauged streams, ca. 1000 soil lysimeters, 150 groundwater wells, >500 permanent forest inventory plots, and a 150 m tall tower (a combined ecosystem-atmosphere station of the ICOS, Integrated Carbon Observation System) for measurements of atmospheric gas concentrations and biosphere-atmosphere exchanges of carbon, water, and energy. In addition, the KCS has also been the focus of numerous high resolution multi-spectral LiDAR measurements and large scale experiments. This large collection of equipment and data generation supports a range of disciplinary studies, but more importantly fosters multi-, trans-, and interdisciplinary research opportunities. The KCS attracts a broad collection of scientists, including biogeochemists, ecologists, foresters, geologists, hydrologists, limnologists, soil scientists, and social scientists, all of whom bring their knowledge and experience to the site. The combination of long-term monitoring, shorter-term research projects, and large-scale experiments, including manipulations of climate and various forest management practices, has contributed much to our understanding of boreal landscape functioning, while also supporting the development of models and guidelines for research, policy, and management.  相似文献   

11.
李传琼  王鹏  陈波  李燕 《湖泊科学》2018,30(1):139-149
于2015年1月和7月在赣江干流和主要支流37个采样点共采集74个水样,分析赣江水系15种溶解态金属元素(Be、Al、V、Mn、Fe、Co、Ni、Cu、As、Mo、Cd、Sb、Tl、Pb、U)的空间分布特征和污染来源的贡献率.结果表明:多数水样的溶解态金属元素浓度符合水质标准,主要的超标元素是Fe,样品超标率为21.60%,其次为As(8.10%)、Mn(4.05%)、Tl(4.05%)和Al(1.35%).Be、Al、V、Fe、Co、Ni、Cu、U浓度在枯水期显著高于丰水期,其他元素差异不显著.依据溶解态金属元素的空间分布特征,赣江流域可分为3个区域:湘水、章水和赣江赣州市段(C1),桃江、袁水和锦江(C2),其他区域(C3);溶解态金属元素水平大小排序为C1C2C3,其中Be、Al、Cu、Mo、Sb、As浓度在C1最高,V、Mn、Fe、Ni、Cd浓度在C2最高.采矿废水、矿渣和农田土壤降雨淋滤、钢铁冶炼废水是赣江溶解金属元素的主要来源;Be、Al、Cu、Pb、U的污染源超过40%来自采矿废水,Cu、As、Mo、Cd的污染源超过35%来自矿渣和农田土壤降雨淋滤,V、Mn、Co、Ni的污染源超过41%来自钢铁冶炼废水.  相似文献   

12.
江苏省农村民居集中住宅区房屋抗震性能探讨   总被引:1,自引:0,他引:1  
本文通过对常熟市、扬州市、姜堰市部分村镇的农村民居集中住宅区房屋建设进行调查和分析,阐述了江苏省农村民居集中住宅区房屋抗震性能的新型结构类型、斜坡屋面结构、内部结构等典型问题,探讨了改善农村民居集中住宅区房屋抗震性能的政策保证、技术支持、资金来源以及其他方面的途径和建议,对农村民居集中住宅区防震减灾及抗震实用化技术的研究与开发具有重要应用价值,为农村民居集中住宅区建设中改善房屋抗震性能提供参考和依据。  相似文献   

13.
利用地震前兆数据跟踪分析平台,搜集并梳理全国定点形变观测台SS-Y型伸缩仪2016—2018年数据跟踪分析观测系统事件记录、观测日志,按影响因素分类,归纳为前置放大器、传感器、主机、供电、传输线路、避雷器、标定装置等13种故障类型,分析各故障类型中发生的曲线特征与技术解决措施,为基层台站伸缩仪观测日常运维中快速锁定故障位置提供参考,进一步提高观测数据的完整性、连续性,提高数据跟踪分析工作的实际效能。  相似文献   

14.
目的:评价CTA在诊断及治疗颅内动脉瘤中的临床应用价值。方法:97例临床疑似颅内动脉瘤患者中首先随机选择CTA及MRA两种无创伤检查中的一种,随后均行DSA检查。以DSA和外科手术确诊为参考,比较CTA,MRA及DSA在诊断颅内动脉瘤中的优势和不足。选择相应治疗后,行CTA+DSA或MRA+DSA复查,评价动脉瘤的残留情况。结果:①50例行CTA+DSA检查组中,确诊阳性病例46例。CTA检测的特异性、灵敏性及准确性分别为66.67%、100%和98%。阴性及阳性预测率分别为100%和97.92%。DSA检测的特异性、灵敏性及准确性分别为66.67%、95.74%和94%。阴性及阳性预测率分别为50%和97.83%。②47例行MRA+DSA检查组中,确诊阳性病例45例。MRA检测的特异性、灵敏性及准确性分别为50%、97.67%和93.62%。阴性及阳性预测率分别为66.67%和95.45%。DSA检测的特异性、灵敏性及准确性分别为66.67%、97.73%和95.74%。阴性及阳性预测率分别为66.67%和97.73%。③48例接受动脉瘤颈夹闭术的患者行CTA+DSA复查,以DSA为标准,CTA评价动脉瘤残留的特异性、灵敏性及准确性分别为97.73%、100%和97.78%。42例接受可解脱弹簧圈治疗的患者行MRA+DSA复查,以DSA为标准,MRA评价动脉瘤残留的特异性、灵敏性及准确性分别为100%、66.67%和97.5%。结论:CTA诊断颅内动脉瘤的特异性、灵敏性及准确性稍优于DSA,MRA对于颅内动脉瘤的诊断方面稍低于DSA;同时CTA及MRA均可清晰显示动脉瘤的三维结构及空间关系;综合比较,我们认为CTA对于动脉瘤的诊断及手术方案的确定能提供更多的信息,并可作为术后较为理想的随访影像学检查方法。   相似文献   

15.
目的:根据多排螺旋CT肺部亚实性结节(SSN)三维重建的定量参数、血液肿瘤标志物和血常规指标,建立用于判断有浸润倾向肺腺癌的多参数诊断模型。材料与方法:回顾性纳入107例接受薄层CT扫描,术后行组织学检查,并做了血液肿瘤标志物和血常规检查的患者。评估指标包括患者年龄、性别;SSN在CT三维重建中的最大径、总体积、实性成分占比和平均CT值;以及血液实验室指标:CEA、CYFRA21-1、NSE、CA125、CA153、CA242、CA199、CA724、SCC、CRP、WBC、NEUT和NEUT%。建立多元logistic回归模型,采用受试者工作特征曲线下面积(AUC)评价该模型对有浸润倾向SSN的诊断能力。结果:在良性和浸润前病变组(51例),以及微浸润腺癌和浸润性腺癌组(56例)之间,年龄、SSN最大径、总体积、实性成分占比和平均CT值有显著差异(P<0.05)。上述参数建立的多元回归模型中,SSN最大径(P=0.007)和实性成分占比(P=0.004)具有显著性。SSN最大径、实性成分占比和多元模型预测有浸润倾向SSN的AUC分别为0.764、0.749和0.801。结论:在体检可以获得的CT定量和一些血液肿瘤标志物和血常规参数中,使用SSN最大径和实性成分占比建立综合诊断模型,能有效预测SSN的浸润性,有助于在肺癌筛查中发现需要手术的患者。   相似文献   

16.
中国水文、工程、环境物探的回顾和展望   总被引:1,自引:0,他引:1       下载免费PDF全文
回顾了我国水文、工程和环境物探近50年的历史,简介了我国水文、工程、环境物探发展的四个阶段.重点论述了我国能源、交通和城市工程物探在电力、铁路、水利建设以及海洋平台工程建设等领域内取得的重大成就;介绍了水资源和地热物探在农业、工业和城市建设中的重要贡献;分析了我国水文、工程、环境物探的技术进步;最后提出了发展方向.  相似文献   

17.
目的:探讨磨玻璃结节样肺腺癌的多排螺旋CT(MSCT)表现及病理基础,旨在提高对该病良恶性诊断的准确性。方法:回顾性分析经病理证实为肺腺癌的21个磨玻璃密度结节(GGNs)病灶的CT资料,分析病灶的大小、性质、瘤肺界面、病灶边缘、空泡征、胸膜凹陷征及穿行支气管、血管的表现,并将病理结果分为浸润前病变和浸润性病变两组进行CT特征的对照。结果:浸润前病变14个,其中13个长径小于2.0 cm,10个为纯磨玻璃结节(pGGNS)、9个瘤肺界面清晰光滑、8个有分叶征、3个有毛刺征;浸润性病变7个,其中4个长径大于2.0 cm,5个为混合型磨玻璃结节(mGGNs)、7个瘤肺界面清晰毛糙、6个有分叶征、6个有毛刺征及4个有棘突征;另外浸润性病变空泡征、胸膜凹陷征及穿行支气管、血管走行及形态的改变较多见。结论:磨玻璃结节样肺腺癌的MSCT表现有一定特征性,GGNs体积较大、呈混合密度(有实性成分)、瘤肺界面清晰毛糙、出现深分叶征、毛刺征或棘突征、空泡征、胸膜凹陷征、病灶内穿行的支气管和血管出现异常改变,提示浸润性病变概率明显增加。   相似文献   

18.
Chen  Fahu  Fu  Bojie  Xia  Jun  Wu  Duo  Wu  Shaohong  Zhang  Yili  Sun  Hang  Liu  Yu  Fang  Xiaomin  Qin  Boqiang  Li  Xin  Zhang  Tingjun  Liu  Baoyuan  Dong  Zhibao  Hou  Shugui  Tian  Lide  Xu  Baiqing  Dong  Guanghui  Zheng  Jingyun  Yang  Wei  Wang  Xin  Li  Zaijun  Wang  Fei  Hu  Zhenbo  Wang  Jie  Liu  Jianbao  Chen  Jianhui  Huang  Wei  Hou  Juzhi  Cai  Qiufang  Long  Hao  Jiang  Ming  Hu  Yaxian  Feng  Xiaoming  Mo  Xingguo  Yang  Xiaoyan  Zhang  Dongju  Wang  Xiuhong  Yin  Yunhe  Liu  Xiaochen 《中国科学:地球科学(英文版)》2019,62(11):1665-1701
The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.  相似文献   

19.
Meng  Zhiyong  Zhang  Fuqing  Luo  Dehai  Tan  Zhemin  Fang  Juan  Sun  Jianhua  Shen  Xueshun  Zhang  Yunji  Wang  Shuguang  Han  Wei  Zhao  Kun  Zhu  Lei  Hu  Yongyun  Xue  Huiwen  Ma  Yaping  Zhang  Lijuan  Nie  Ji  Zhou  Ruilin  Li  Sa  Liu  Hongjun  Zhu  Yuning 《中国科学:地球科学(英文版)》2019,62(12):1946-1991
Synoptic meteorology is a branch of meteorology that uses synoptic weather observations and charts for the diagnosis,study,and forecasting of weather.Weather refers to the specific state of the atmosphere near the Earth's surface during a short period of time.The spatial distribution of meteorological elements in the atmosphere can be represented by a variety of transient weather phenomena,which are caused by weather systems of different spatial and temporal scales.Weather is closely related to people's life,and its development and evolution have always been the focus of atmospheric scientific research and operation.The development of synoptic meteorology is closely related to the development of observation systems,dynamical theories and numerical models.In China,observation networks have been built since the early 1950 s.Up to now,a comprehensive meteorological observation systembased on ground,air and space has been established.In particular,the development of a new generation of dense radar networks,the development of the Fengyun satellite series and the implementation of a series of large field experiments have brought our understanding of weather from large-scale environment to thermal dynamics,cloud microphysical structure and evolution characteristics of meso and micro-scale weather systems.The development of observation has also promoted the development of theory,numerical model and simulation.In the early days,China mainly used foreign numerical models.Lately,China has developed numerical model systems with independent intellectual property rights.Based on the results of high-resolution numerical simulations,in-depth understanding of the initiation and evolution mechanism and predictability of weather at different scales has been obtained.Synoptic meteorology has gradually changed from an initially independent development to a multidisciplinary approach,and the interaction between weather and the change of climate and environment has become a hot and frontier topic in atmospheric science.This paper reviews the important scientific and technological achievements made in China over the past 70 years in the fields of synoptic meteorology based on the literatures in China and abroad,from six aspects respectively including atmospheric dynamics,synoptic-scale weather,typhoon and tropical weather,severe convective weather,numerical weather prediction and data assimilation,weather and climate,atmospheric physics and atmospheric environment.  相似文献   

20.
青藏高原东缘地壳上地幔电性结构研究进展   总被引:6,自引:2,他引:4       下载免费PDF全文
经过数十年的努力,中国学者针对青藏高原东缘地壳上地幔探测,累积完成超过20000 km的大地电磁测深剖面,取得了一系列重要科学数据和认识,为青藏高原东缘构造格局、地壳上地幔电性结构、地震机制和动力学研究奠定了基础.根据青藏高原东缘的主要构造和断裂分布特征,本文重点对龙门山构造带、川滇构造带和三江构造带三个构造带分区进行研究,主要依据大地电磁探测工作成果和壳幔电性结构特征,系统地对青藏高原东缘地壳上地幔电性结构、与扬子西缘接触关系、汶川地震和芦山地震的电性孕震环境及弱物质流通道等几个方面进行了梳理和分析.一是青藏高原东缘地壳表层岩块和物质沿壳内高导层向龙门山造山带仰冲推覆,表现为逆冲推覆特征的薄皮构造;二是高原东部地壳中下部及上地幔顶部向龙门山造山带和上扬子地块西缘岩石圈深部俯冲,呈现刚性的上扬子地块西缘高阻楔形体向西插入柔性青藏块体的楔形构造;三是将汶川地震和芦山地震的震源投影到大地电磁剖面上,发现震源位于剖面下方的高阻块体与低阻体之间靠近高阻体的一侧,龙门山构造带岩石圈表现出高阻、高密度和高速的"三高"特征,这种非均匀电性结构可能构成地震孕育发生条件;四是川滇和三江地区的多条大地电磁剖面探测结果表明,在青藏高原东缘中下地壳存在下地壳流和局部管道流,大地电磁结果对其空间分布形态、位置及大小进行了较好的刻画.根据研究区壳幔电性结构特征的构造解析和综合实例分析,总结了青藏高原东缘六类壳幔电性结构模型,提出了下一步重点研究领域和目标.总之,青藏高原东缘壳幔电性结构的研究对揭示研究区岩石圈结构和构造格局提供了重要依据,对油气及矿产资源远景评价提供了背景资料,对"Y"型多地震区的构造关系和发震机理研究具有重要指导意义.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号