华北板块南缘中段中上三叠统软沉积变形构造的发现及其地质意义     

全晓园  刘池洋  张龙  张东东  王建强  马奂奂  冯琦  翟光麾 《现代地质》2020,34(2):333-344

豫西地区中上三叠统主要出露在济源、义马、伊川和南召一带。印支期秦岭造山运动控制和影响着邻区中上三叠统盆地属性和沉积地层展布。通过观察研究区野外露头剖面,发现中上三叠统发育一系列典型的软沉积变形构造,包括液化底辟、枕状构造、液化柱、液化卷曲变形、负载、球-枕、火焰状构造、液化角砾岩。这些软沉积变形在垂向上表现出明显的复现性,在侧向上表现为沿地层连续展布,表明该时期研究区内地层受到频繁强烈的地震影响。通过对这些软沉积现象的识别和形成机制解释,判定其触发因素为秦岭造山过程中伴生的地震。区内地层中震积岩的存在即是对秦岭造山过程中构造活动的响应。  相似文献   

构造-岩浆作用对热液活动的控制机理: 马努斯海盆为例   总被引：2，自引：2，他引：0  

马瑶  殷学博  王晓媛  陈帅  曾志刚 《海洋科学》2018,42(5):163-171

综述了马努斯海盆热液区构造特征、基底差异, 结合马努斯海盆热液区热液活动与构造-岩浆特征, 探讨了二者的耦合关系, 以及构造-岩浆作用对热液活动的影响和控制。马努斯海盆位于西南太平洋俾斯麦海的东北部, 是世界上扩张速度最快的海盆之一。马努斯海盆西部(马努斯扩张中心, Manus Spreading Center, MSC)主要由海盆扩张成熟期产生的大洋中脊玄武岩组成, 属于成熟弧后扩张中心,发育Vienna Woods热液区; 海盆东部(东南裂谷, Southeast Rift, SER)则是一个拉张裂谷, 处于扩张的早期阶段, 属于不成熟弧后扩张中心, 发育PACMANUS、DESMOS、SuSu Knolls三大热液区。MSC与大洋中脊的热液活动相似, 而SER因受到火山、俯冲作用影响更为显著, 其热液流体具有岩浆流体和俯冲流体的特征。与Vienna Woods热液压相比, PACMANUS、DESMOS以及SuSu Knolls三个热液区的水深相对较浅(1 150～1 740 m), 是地球内部热物质由内向外迁移的结果, 其下部岩浆作用强烈。此外,岩浆脱气作用和数值模拟结果表明, PACMANUS热液系统中具有岩浆流体的输入。与Vienna Woods热液区相比, PACMANUS、DESMOS、SuSu Knolls热液区的热液活动强度及流体组成主要受控于岩浆作用。  相似文献   

Spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015     

Cong Xie  Leiguang Wang  Xing Fang  Wenzhi Liao 《International Journal of Digital Earth》2018,11(11):1085-1102

China has experienced unprecedented urbanization in the past decades, resulting in dramatic changes in the physical, limnological, and hydrological characteristics of lakes in urban landscapes. However, the spatiotemporal dynamics in distribution and abundance of urban lakes in China remain poorly understood. Here, we characterized the spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015 using remote-sensing data and landscape metrics. The results showed that the urban lake landscape patterns have experienced drastic changes over the past 25 years. The total surface area of the urban lakes has decreased by 17,620.02?ha, a decrease of 24.22%, with a significant increase in the landscape fragmentation and a reduction in shape complexity. We defined three lake-shrinkage types and found that vanishment was the most common lake-shrinkage pattern, followed by edge-shrinkage and tunneling in terms of lake area. Moreover, we also found that urban sprawl was the dominant driver of the lake shrinkage, accounting for 67.89% of the total area loss, and the transition from lakes to cropland was also an important factor (19.86%). This study has potential for providing critical baseline information for government decision-making in lake resources management and urban landscape design.  相似文献   

华蓥山中段地区地下水资源量评价   总被引：1，自引：1，他引：0  

康小兵  罗声  许模  刘宏 《中国岩溶》2018,37(4):527-534

四川华蓥山中段地区水流失比较严重,供需矛盾突出,水环境持续恶化,不但影响到居民正常的生产和生活,而且严重影响了该地区国民经济的建设和发展。通过野外调查和综合分析现场收集的资料,总结出华蓥山中段地区地下水资源量流失情况:该区每年流失的水资源量约为0.914 4亿m3,且华蓥山褶皱西翼水流失总量大于东翼,而西翼北端是区内水流失量最严重的区域,其水资源量流失的影响因素主要为气候、社会发展及人类活动等。   相似文献   

2021-04-16河北滦州M_S4.3地震前的大气电场异常信号分析     

陈涛  王诗涵  李磊  杨牧萍  张灵倩  张学民  黄辅琼  刘静  熊攀  提烁  吴晗  宋佳军  王聪  苏建峰  罗静 《大地测量与地球动力学》2022,42(8):771-776

中国科学院国家空间科学中心分布在天津市宝坻区和廊坊市永清县的2个观测台站在2021-04-16河北滦州M_S4.3地震前均观测到大气电场异常。宝坻站监测到过境云与地质活动混合型电场异常信号;永清站监测到湾型持续电场异常信号,属于典型的临震前小时尺度先兆信号,其幅度和持续时间均明显高于宝坻站的异常电场信号。对比电场异常期间2个台站的气象活动和空间天气活动发现,虽然2台站电场异常信号的表现方式不同,但背景变化中均隐含大型地质活动信号。分析结果表明,未来可通过分析多源活动导致的空间静电演变过程,形成有效的识别方法,在一定的气象活动范围内,从大气静电监测数据中提取中等以上强度地震的前兆信息。  相似文献   

中国地下水资源演变趋势及影响因素分析   总被引：1，自引：0，他引：1       下载免费PDF全文

陈飞  徐翔宇  羊艳  丁跃元  郦建强  李原园 《水科学进展》2021,31(6):811-819

中国地下水资源发生了显著变化,全面摸清地下水资源演变趋势及其影响因素是治理和管理地下水资源的基础。基于全国水资源调查评价、中国水资源公报等资料,对中国60余年来地下水资源的演变规律与影响因素进行了系统分析。结果表明：全国地下水资源量总体稳定,但区域演变趋势差异明显,海河区、辽河区、黄河区呈明显衰减态势;地下水补给结构发生重大变化,由自然补给演变为自然与人工补给并存的模式;地下水排泄结构发生巨大变异,由天然排泄逐渐演变为以人工排泄为主。海河区、松花江区、黄河区、西北诸河区等区域地下水补给排泄关系严重失衡,超采问题突出;降水变化、下垫面条件改变、人类活动干扰是地下水资源变化的主要原因。  相似文献   

旅游活动与水环境耦合分析——以玉龙雪山-丽江盆地为例     

窦文康  王泽平  方金鑫  韩彤彤  蒲焘  张鹏 《冰川冻土》2021,43(4):1210-1217

玉龙雪山是我国季风海洋型冰川发育最为典型的代表性地区,也是北半球最靠近赤道的现代冰川区。丽江市的部分水源来自于玉龙雪山冰川融水,同时玉龙雪山景区每年吸引着上千万的游客来欣赏现代冰川。旅游活动与水环境息息相关且相互作用,水环境的准确刻画是指导与优化区域旅游活动的基础。以世界著名旅游城市丽江市为例,基于实地采样与数据分析,对2018年丽江市的旅游活动与水环境进行耦合分析。结果表明：丽江市旅游活动与水体污染耦合度极高,旅游活动与水体富营养化和水体毒理的耦合度较低。旅游活动与水环境存在较强的关联,特别是与水环境指标中的高锰酸盐指数,存在强烈的耦合关系。总体上,旅游活动与水环境存在相关关系,旅游旺季水环境质量较旅游淡季更差。  相似文献   

Microplastic pollution in surface water and sediments of Qinghai-Tibet Plateau: Current status and causes     

《China Geology》2021,4(1):178-184

To study the current status and causes of the microplastic pollution in surface water of the Qinghai-Tibet Plateau, this paper compared the average microplastic abundance in sediments and surface water of the Qinghai-Tibet Plateau and the results are as follows. First, the average microplastic abundance in surface water of the independent rivers and the whole area is 247–2686 items/m³ and 856 items/m³, respectively. The average microplastic abundance in sediments of independent rivers or lakes and the whole area is 0–933 items/m² and 362 items/m², respectively. Meanwhile, the degree of microplastic pollution in river sediments is higher than that in lake sediments, and the rivers suffering from microplastic pollution mainly include the Brahmaputra River, Tongtian River, and Nujiang River. Second, compared with the microplastic pollution in other areas of the world, the levelof microplastic pollution in the lakes and rivers of the Qinghai-Tibet plateau is not lower than that of well-developed areas with more intensive human activities. Finally, this study suggests that relevant government departments of the Qinghai-Tibet Plateau should strengthen waste management strategies while developing tourism and that much attention should be paid to the impacts of microplastics in the water environment.©2021 China Geology Editorial Office.  相似文献   

Holocene initiation and expansion of the southern margins of northern peatlands triggered by the East Asian summer monsoon recession     

《地学前缘(英文版)》2023,14(2):101526

Northern peatlands represent one of the largest biospheric carbon reservoirs in the world. Their southern margins act as new carbon reservoirs, which can greatly influence the global carbon dynamics. However, the Holocene initiation, expansion and climate sensitivity of these peatlands remain intensely debated. Here we used a compilation of basal peat ages across six isolated peatlands at the southern margins of northern peatlands to address these issues. We found that the earliest initiation event of these peatlands occurred after the Younger Dryas (YD, 12,800–11,700 years ago) period. The second initiation event and rapid expansion occurred since 5 ka cal. BP. The recession of East Asian summer monsoon (EASM) during the YD period and at around 5 ka cal. BP likely played a major role in controlling the initiation and expansion of these peatlands. The rapid expansion of these peatlands possibly contributed to the significant increases in atmospheric methane concentrations during the late Holocene because of the minerotrophic fens status and rapid expansion of them. These ecological processes are different from northern peatlands, indicating the special carbon sink and source implications of these peatlands in the global carbon cycle.  相似文献   

现代河流沉积物碎屑及矿物组分研究新进展     

梁文栋  胡修棉 《地质学报》2023,97(9):2975-2991

现代河流沉积物忠实地记录了流域盆地内的母岩、风化、搬运和沉积过程中的化学、物理过程以及人类活动的改造作用,是探索和验证源- 汇系统等理论的重要媒介。本文以全球现代河流砂组分数据库为基础,总结了碎屑组分、重矿物组分在不同大陆的分布特征,探讨了其在物源识别、源区贡献率计算、沉积物产生及搬运过程中气候- 构造等影响因素的评估、对源- 汇系统的研究启示等方面的应用。今后建议加强基于大数据的沉积物组分对气候- 构造- 人类活动的响应、沉积物产生及通量、高时间分辨率的沉积物组分变异性、不同物源定量化方法的差异等方面的研究。  相似文献