川西岷江松潘段第四纪与新构造运动特征分析     

韩建恩  郭长宝  吴瑞安  任三绍  胥彪  杨志华 《地质力学学报》2017,23(6):864-881

在已有调查研究的基础上,通过野外地质调查和剖面测量,重点分析了岷江松潘段的漳腊盆地、斗鸡台盆地地貌特征、第四纪沉积物类型、物质成分、空间分布等特征,并系统测量和研究了松潘段岷江干流及其支流的河流阶地特征。研究表明,新构造运动控制了松潘段第四纪盆地的形态和地貌演化过程,漳腊盆地和斗鸡台盆地形成于中新世末至上新世初,西侧控盆断裂为东倾正断层,东侧为西倾逆断层,盆地为断块发生西降东升的翘板式断块运动过程中形成的,称之为"翘板式箕状盆地"。松潘段岷江河谷地貌呈现出宽谷和窄谷交替出现的特点,岷江干流及其支流中发育多处湖相地层,沉积特征表现为堰塞湖。岷江上游松潘段最多发育6级阶地,以侵蚀阶地和堆积阶地为主,主要形成于中更新世晚期—全新世时期。阶地级数具有分段性特点,不同区段阶地阶面宽窄不一,受区内新构造活动控制明显。岷江上游新构造运动表现为南北条带性和东西向差异掀斜抬升的特点,红桥关以上整体为构造隆升区,至少具有3次构造隆升,岷江上游斗鸡台盆地构造隆升强度整体上大于漳腊盆地。在尕米寺地区可能发生了6次构造抬升,红桥关一带构造抬升明显要强于漳腊盆地。  相似文献   

Relationships Between Long-Term Trend of Satellite-Derived Chlorophyll-<Emphasis Type="Italic">a</Emphasis> and Hypoxia Off the Changjiang Estuary     

Jianyu Chen  Delu Pan  Mingliang Liu  Zhihua Mao  Qiankun Zhu  Ninghua Chen  Xiaoyu Zhang  Bangyi Tao 《Estuaries and Coasts》2017,40(4):1055-1065

The Changjiang Estuary is one of the largest estuaries in the world, where hypoxia frequently occurs during the summer season. Recent routine surveys in the observed area found that the low dissolved oxygen (DO) in the summer bottom water was not rapidly expanding with increasing nutrient loads in Changjiang diluted waters. Based on the remote sensing data and in situ data, we examined the historic seasonal hypoxia observations for the bottom waters of the Changjiang Estuary and investigated the short- and long-term effects that runoff had on variations in DO and chlorophyll-a (Chl-a). Our analysis indicated that the recent areal variation in hypoxia was due to the changing Chl-a distribution and stratification conditions. The correspondence between hypoxia and surface Chl-a concentration showed that remotely sensed Chl-a larger than 3.0 mg L^?1 was an essential condition for the formation of hypoxia off the Changjiang Estuary. The trend of Chl-a concentration was significantly impacted by the Three Gorges Dam (TGD), and the inter-annual variation of Chl-a was weakly affected by global-scale climate variability. After the TGD impoundment, the sediment loading in the Changjiang runoff and suspended sediments in Changjiang Estuary in August decreased, and the high Chl-a concentration moved landward. These shifted the hypoxia from its optimal forming conditions.  相似文献   

居隆庵铀矿床酸碱交代叠合成矿特征     

王峰  林锦荣  胡志华  王勇剑 《铀矿地质》2017,(3):144-149

坑道地质观测和取样研究表明,居隆庵铀矿床不仅发育酸交代型铀矿化,也普遍存在碱交代型铀矿化,而且碱交代早于酸交代,酸、碱交代型铀矿化在空间上叠合形成富矿。碱交代型矿化蚀变矿物组合为钠长石-赤铁矿-绿泥石-碳酸盐;酸交代型矿化蚀变矿物组合为萤石-伊利石-绿泥石-磷灰石。碱交代型矿石铀主要以分散吸附状态存在;酸交代型矿石铀主要存在于沥青铀矿中,少量存在于钛铀矿、铀(钍)石中。碱交代型矿石具有富Na、低K含量和LREEHREE等特点,矿化指示元素组合为U、Sr、W、Y、LREE、Yb、Th;酸交代型矿石有富F、S、P,HREELREE等特点,矿化指示元素组合为U、P、Sb、W、Yb、Lu、Th、Y、HREE、Mo、Cd、Pb。  相似文献   

Lake evolution and its implication for environ-mental changes in China during 1950?2000     

HUANG Zhihua  XUE Bi  YAO Shuchun  PANG Yong 《地理学报》2008,18(2):131-141

Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an im-portant role on the recent decades’ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume (water level, depth and area) in the eastern and western lake regions of China during 1950–2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect.  相似文献   

贵州2010年6月28日关岭滑坡遥感应急调查          下载免费PDF全文

王治华  郭大海  郑雄伟  王建超  郭兆成  董丽娜 《地学前缘》2011,18(3):310-316

2010年6月28日,贵州省关岭县发生大规模滑坡,2010年6月30日中国国土资源航空物探遥感中心根据国土资源部中国地质调查局的部署,紧急派机飞往灾区进行航摄,获取了灾后第3天的高分辨率航摄图像数据,经正射处理后,进行解译提供灾区使用。该解译以QuickBird数据、航摄数据及1∶50 000数字地形、航摄立体像对生成的DEM分别作为滑坡前后的遥感数据源及地理控制数据源。采用数字滑坡技术估算了628关岭滑坡灾害的灾损,解译了滑坡的形态结构及运动方式,利用滑坡前后DEM计算了原斜坡滑走及堆积的滑坡方量,分析了628关岭滑坡成因及存在的地质灾害隐患,并提出防治措施建议。  相似文献   

REE geochemistry of surface sediments in the Chukchi Sea   总被引：4，自引：0，他引：4  

陈志华  高爱国  刘焱光  孙海清  石学法  杨作升 《中国科学D辑(英文版)》2003,46(6):603-611

Rare earth elements (including the lanthanides and Y) have analogical chemical properties and low solubility, and they are not easy to transfer and take inter-element fractionation during geological processes such as weathering, disintegration, transporta…  相似文献   

Preparation of carboxymethyl sulfochitosans with differentially substituted regions     

ZHAO Xia *  LV Zhihua  XU Jiamin  YU Guangli Insititute of Marine Drug  Food  Ocean University of China  Qingdao  P..R.China 《中国海洋大学学报(英文版)》2003,2(1):69-74

1　Introduction　Derivativesofchitosansulfateareknowntohaveimportantantithrombin (Drozdetal.,2 0 0 1;Hagiwaraetal.,1999;Tuetal.,1999) ,antiarteriosclerotic(Dingetal.,2 0 0 1;Gamzazadeetal.,1997) ,an timetastatic (Murataetal.,1990 )andantiviral(Nishimuraetal.,1998) pharmacologicalactivitiesduetotheirsimilarskeletalstructuretoheparinandtheirtypicalpolyanionproperties .Furthermore ,theyplayimportantrolesinwoundhealing ,tumorgrowthandangiogenesis ,dependingonthetypeoffunctionalgroups,theamountan…  相似文献   

白令海与西北冰洋表层沉积物中四醚膜类脂物研究及其生态和环境指示意义     

王寿刚  王汝建  陈建芳  陈志华  程振波  汪卫国  黄元辉 《地球科学进展》2013,28(2):282-295

通过对中国第3次和第4次北极考察在白令海和西北冰洋采集的65个表层样沉积物中生物标记物四醚膜类脂物(GDGTs)的研究,发现西北冰洋表层沉积物中类异戊二烯和支链GDGTs的浓度分布大致以楚科奇海和波弗特海的陆坡为界线,呈现南高北低的特征,这一特征主要与水体生产力和陆源有机质的输入量有关.基于GDGTs的陆源输入指数BIT显示,从楚科奇海北部到高纬度区的阿尔法脊,陆源有机质的相对比例明显增加,与有机碳稳定同位素等结果一致,表明BIT可以用来指示北极陆源有机质输入量的变化.应用前人TEXL86-SST方程估算的研究区表面海水温度SST与现代年均SST和夏季平均SST的相关性较差,原因可能与陆源输入的类异戊二烯GDGTs干扰以及低的古菌生产力有关.从季节性海冰覆盖区到永久性海冰覆盖区,基于支链GDGTs的环化指数CBT明显升高,可能反映了CBT对海冰覆盖状况的响应,但其响应机制还不清楚.基于支链GDGTs的环化指数CBT和甲基化指数MBT估算的北极陆地年均大气温度和土壤pH差异较大,可能是由表层沉积物的来源复杂以及混合作用造成的.  相似文献   

甘肃银硐梁锑矿床地质特征及控矿因素分析   总被引：1，自引：1，他引：0  

葛枝华  韩力  韩龙梅 《中国地质调查》2018,5(5):29-34

近些年来,在西秦岭锑成矿带中发现了中型规模的甘肃银硐梁锑矿床。通过论述该锑矿床的地质特征,分析并讨论该矿床的控矿因素及找矿标志。结果表明: 该锑矿床主要赋存于三叠纪官亭群中部建造层第二岩性段、钙质硅化石英砂岩夹泥质粉砂岩的断层破碎带和层间破碎带中; 锑矿化明显受地层和断裂破碎带控制,为成矿提供成矿物质、热液条件和赋存空间,较早形成的NW向断裂是导矿构造,较晚形成的NE向次级断裂是赋矿构造; 成矿物质主要来源于地层,成矿热动力主要来源于构造运动,成矿作用以热液充填为主; 银硐梁锑矿床属于低温热液裂隙充填型层控矿床。  相似文献   

地理学视角下土地利用/覆被分类发展探讨     

王志华  郜酷  杨晓梅  苏奋振  黄翀  石铁柱  颜凤芹  李贺  张慧芳  吕宁  潘婷婷 《地理研究》2022,41(11):2946-2962

随着对地观测和互联网技术的发展,地理大数据时代正在到来,其多尺度、长时序、多模态等海量“超”覆盖数据为土地利用/覆被（Land Use/Land Cover, 简称LULC）分类及变化检测带来巨大的机遇,支撑着新时代人、地两大系统相互作用关系的认知和实践。然而,多数地理学者认为地理学基本原理与核心思想并未因为大数据的到来而发生本质性变化。所以,从地理学基本原理角度理解LULC分类的发展,尤其在地理大数据时代的发展方向,不失为一条可行的途径。为此,本文从区域、尺度、综合三方面的地理学基本原理视角将LULC分类技术的发展划分为地球观测数据匮乏阶段、人类行为数据融合阶段以及地理大数据“超”覆盖阶段分别探讨分析,以期主动把握LULC分类技术及应用的未来发展趋势。研究结果显示：在地球观测数据匮乏阶段,LULC分类多以类型还不丰富的遥感数据源,在空间分辨率较低的像元尺度上,进行以地表覆被状态为主的分类;发展到人类行为数据融合阶段,LULC分类在城市区域率先出现了对地观测数据和人类行为数据相融合,在街区尺度上进行以空间功能异质性划分、识别为主导的城市功能区分类;在地理大数据“超”覆盖阶段,LULC分类将实现多尺度协同、面向全空间的功能异质性划分,并在主体功能的基础上融合“社会-经济-自然”多维定量属性,本文称之为“空间场景”。希望本文的探讨能够为地理大数据时代LULC分类的新技术发展和新产品应用提供有益启示。  相似文献