纹层状细粒碳酸盐岩成因:以贵州习水吼滩剖面下奥陶统为例          下载免费PDF全文

孙永超  刘建波 《古地理学报》2016,18(5):743-758

纹层是组成层理的基本单位,既可以是低能深水沉积环境的产物,也可能形成于高能环境中。在受风暴影响的区域,微小的泥质颗粒能够在流动过程中发生絮凝形成絮粒并沉积下来形成纹层。贵州习水吼滩剖面下奥陶统桐梓组碳酸盐岩纹层发育,纹层中风暴沉积构造丰富,包括风暴侵蚀面和渠模等。基于细致的野外观察和室内沉积学研究,将在风暴作用影响下形成的纹层划分为5个类型:平行厚纹层、单向交错薄纹层、平行薄纹层、波状厚纹层和水平厚纹层。采用EDS元素面扫描方法,发现亮、暗纹层中都含有铝、硅和镁元素且分布都比较均匀,而暗纹层所含黏土矿物稍多,所以暗纹层中3种元素的含量比亮纹层的稍高。利用开尔文—赫姆霍兹不稳定性解释了亮、暗纹层的形成机制,即絮粒与未发生絮凝的微小颗粒在开尔文—赫姆霍兹不稳定性作用下交替沉积,其中以絮粒为主的纹层更容易发生重结晶形成亮纹层。根据各纹层不同的垂向结合序列划分出3种风暴序列,且从Ⅰ型到Ⅲ型风暴作用逐渐减弱。  相似文献   

溱潼凹陷阜一段层序地层格架及沉积体系研究     

杜民  陆永潮 《海洋地质译丛》2012,(1):33-38

溱潼凹陷属走滑伸展型断陷,应用层序地层学原理和方法,建立了阜一段的层序地层格架,并在阜一段识别出湖泊三角洲和湖泊两大沉积体系。同时结合含砂率与地震属性研究,恢复了阜一段低位域、湖扩域和高位域的沉积体系,认为各体系域沉积体系在时空展布上具有一定的继承性和差异性。综合分析认为,研究区阜一段东部的殷庄—广山地区在低位域时发育大型三角洲沉积体系,主要以前缘河口坝及席状砂沉积为主,可作为良好储集层;西部斜坡带华港—北汉庄地区,低位域及高位域均发育三角洲沉积体系且规模较大,主要为平原河道及前缘河口坝沉积,也可作为很好的油气储层。  相似文献   

一种基于非线性主成分分析的高光谱图像目标检测方法     

孙康  耿修瑞  唐海蓉  赵永超 《测绘通报》2015,(1):105-108

目标探测是高光谱图像的重要应用之一.目前已经有了很多的目标探测算法,然而这些算法要求目标与背景是线性可分的.在实际的高光谱数据中,这一要求往往难以满足.本文提出了一种基于非线性主成分分析的高光谱图像目标探测算法.该方法先利用神经网络将高光谱图像进行非线性降维,从而使得在降维后的数据中目标与背景线性可分;然后使用约束能量最小化算法进行目标探测,为了取得较好的目标探测效果,保留了图像原始的特征.针对模拟数据和真实高光谱图像数据的试验表明,基于神经网络的非线性主成分分析可以将线性不可分的目标与背景分离.使用非线性特征和原始特征的组合可以获得更好的目标探测效果.  相似文献   

A review on anthropogenic geomorphology   总被引：1，自引：1，他引：0  

Jialin Li  Lei Yang  Ruiliang Pu  Yongchao Liu 《地理学报(英文版)》2017,27(1):109-128

With the continuous development of man’s ability to reshape nature, human activities have become the third geomorphologic agent in the modern geomorphological process. Man-made landform is a landform unit characterized by human activities and is a result of synergizing human and nature geomorphologic agents under the physical geographical background. This article provides an overview on the major progresses in research on anthropogenic geomorphology from aspects like the origin of anthropogenic geomorphology, man-made landform agents and classification, man-made landform evolution and its influencing mechanism, map presentation of man-made landform, and environmental impact of man-made landforms. In addition, in the article, the future development of anthropogenic geomorphology is forecasted. It is pointed out that future studies on anthropogenic geomorphology should pay more attention to the following directions: construction of discipline system of anthropogenic geomorphology, material composition and morphological features of man-made landforms, spatial expansion process and development laws of man-made landforms, regional disparity and accumulative environmental effects of man-made landforms, and environmental management on man-made landforms and comparative analyses of relevant international management policies.  相似文献   

高分一号卫星在京津矿山遥感监测中的应用     

于博文  田淑芳  赵永超  芦飞  方彦奇 《现代地质》2017,31(4):843

高分一号卫星于2013年成功发射,可获取 2 m全色影像与8 m多光谱影像,在矿山遥感监测中有很大的应用空间。研究并总结了高分一号卫星在矿山遥感监测应用时的数据处理流程和方法,根据高分一号影像特征建立了矿山遥感解译标志并对部分图斑进行了野外验证,最后进行了京津矿山遥感调查与监测工作。通过应用研究得出结论,高分一号卫星拥有较高的分辨率和较好的数据质量,地物轮廓纹理清晰、数据处理方便、解译精度较高,运用高分一号卫星进行矿山遥感监测可以取得良好的效果,可以为国土资源部门制定矿产资源规划、整顿矿产资源开发秩序、治理矿山地质环境等提供技术支撑和决策依据。  相似文献   

The Jurassic structural evolution of the western Daqingshan area,eastern Yinshan belt,North China   总被引：1，自引：0，他引：1  

Yongchao Wang  Wei Shi  Xuanhua Chen  Limin Jia 《International Geology Review》2017,59(15):1885-1907

The western Daqingshan area, located in the eastern Yinshan belt, is dominated by the southern Daqingshan fold-and-thrust system and the northern Shiguai basin. Based on detailed structural investigations, stratigraphic controls, and geochronology, a three-stage tectonic evolution is proposed for the western Daqingshan area during the Jurassic. The discovery of syndepositional normal faults in the Early–Middle Jurassic sequences suggests that an N–S extensional regime (ca. 200–170 Ma) characterized the first deformational stage, which controlled the initial formation of the Shiguai basin. Subsequently, the relatively expansive rift basin was dissected by the initial development of the Daqingshan fold-and-thrust system that was associated with a N–S compressional regime (ca. 170–160 Ma). This phase of deformation involved the Lower–Middle Jurassic synrift sediments into a series of E–W-trending compressional structures, and controlled the deposition of Late–Middle Jurassic Changhangou growth strata ahead of the deformation front. Finally, the progression of Daqingshan fold-and-thrust system was dominated by NW–SE compression (ca. 160–145 Ma), which converted the previous E–W-trending compressional structures into a stepped geometry marked by several NE-trending oblique footwall ramps, and resulted in the depocentre of the Late Jurassic Daqingshan synorogenic conglomerate migrating markedly northeastwards. The driving mechanisms for these three palaeostress fields are considered as asthenosphere upwelling following Permian–Triassic collisional orogenesis, closure of the Mongol–Okhotsk Ocean, and NW-directed subduction of the Palaeo-Pacific plate, respectively.  相似文献   

中扬子地区晚震旦世-早寒武世沉积特征及岩相古地理   总被引：12，自引：1，他引：11       下载免费PDF全文

李忠雄  陆永潮  王剑  段太忠  高永华 《古地理学报》2004,6(2):151-162

中扬子地区指青峰-湘广断裂带以南,湘黔桂海盆以北,鄂西恩施-龙山一线以东的湖北省和湖南省的大部分地区。根据中扬子地区上震旦统-下寒武统十余条代表性剖面的沉积特征及其横向展布规律,应用等时面优势相成图方法编制了晚震旦世的陡山沱期、灯影期,早寒武世的筇竹寺期、沧浪铺早期、沧浪铺晚期、龙王庙期共6幅岩相古地理图。中扬子地区上震旦统发育了从碳酸盐潮坪、开阔台地、浅滩、台地边缘、斜坡到台地前缘盆地等沉积,下寒武统下部主要为细碎屑岩和碳酸盐岩组成的混合型浅海陆棚沉积,上部变成碳酸盐潮坪、开阔台地、台缘斜坡和台缘盆地沉积。晚震旦世岩相古地理格局由碳酸盐台地(鄂中台地)和南边的台缘盆地组成。由于地壳差异性升降运动,晚震旦世陡山沱期岩相古地理格局发生了急剧变化。早寒武世早-中期岩相古地理格局由鄂中古陆、围绕古陆的碳酸盐潮坪、陆棚及南边的陆棚边缘盆地组成。早寒武世中-晚期岩相古地理格局由碳酸盐潮坪、开阔台地、台缘斜坡和台缘盆地组成,该地区主体进入碳酸盐台地演化阶段。  相似文献   

一种计算NaAlSi3O8熔体粘度的理论方法   总被引：2，自引：0，他引：2  

朱永峰  赵永超 《岩石学报》1997,13(2):173-179

硅酸岩熔体的结构特征是制约熔体粘度的主要因素，熔体结构的变异是其中粘流作用发生的原因，化学成分对熔体粘度的控制是通过改变熔体结构而实现的。ＳｉＯ２熔体中仅存在Ｓｉ－Ｏ键，而ＮａＡｌ－Ｓｉ３Ｏ８熔体中存在Ｓｉ－Ｏ键，Ａｌ－Ｏ键和Ｎａ－Ｏ键，Ｎａ－Ｏ键在熔体结构中通过Ｏ与Ｓｉ－Ｏ键相联结，并且使与之相联的Ｓｉ－Ｏ键的键强变弱。因此，熔体结构单元中与Ｎａ－Ｏ键相联结的Ｓｉ－Ｏ键最易断开，并因此导致流变作用的发生。文中计算了不同温度条件下ＮａＡｌＳｉ３Ｏ８熔体中Ｓｉ－Ｏ键的键强，以ＳｉＯ２熔体中的Ｓｉ－Ｏ键的键强和ＳｉＯ２熔体的粘度为标准，建立了计算了ＮａＡｌＳｉ３Ｏ８熔体粘度的理论模型，依此理论模型求得的熔体粘度在合理的地质温度范围内与实验结果完全吻合  相似文献   

近50年来ENSO与祁连山区气温、降水和径流的对应关系     

蓝永超  丁永建  康尔泗  Zhang Jishi 《地理学报(英文版)》2003,13(3)

El Nino and La Nina are the events concerned internationally. The correspondingrelationship between El Nino events, temperature, precipitation and runoff in the Qilian mountain areaare analyzed according to the date from the weather and the hydrometric stations in the area, theresults show that effects of El Nino events to temperature, precipitation and runoff are different in thedifferent time and zones. When El Nino occurs, temperature rises, but precipitation and runoff decreasein the whole Qilian mountain area, especially in the east and middle parts of the area. Temperaturerises, precipitation and runoff still decrease in the eastern Qilian mountain area in the next year ElNino occurring, but decrease extent is fewer. There are not obvious relationship between temperature,precipitation and runoff with El Nino events in the western Qilian mountain area.  相似文献   

Estimation of tree transpiration and response of tree conductance to meteorological variables in desert-oasis system of Northwest China     

CHEN Rensheng  KANG Ersi  ZHANG Zhihui  Zhao Wenzhi  SONG Kechao  Zhang Jishi  LAN Yongchao 《中国科学D辑(英文版)》2004,47(Z1)

Transpirations of three dominated tree species, namely Mongol Scotch Pine (Pinus sylvestris var. mongolica Litvin), White elm (Ulmus pumila) and Gansu Poplar (Populus gansuensis Wang et Yang) in oasis shelter forest (Linze site) and of two dominated tree species,namely Euphrates Poplar (Populus euphratica Oliv.) and Russia olive (Elaeagnus angustifolia Linn.) in lowland desert (Erjinaqi site) have been estimated using measured sapflow in summer,autumn and winter, 2002 and in spring, 2003. An ENVIS System was used for each site to measure microclimate variables, soil moisture and sapflow every half an hour, and the study time scale is one day. In the 104 days of observation during the growing season at the Linze site, the average daily sapflow of Gansu Poplar is 9.93L·d-1,and the average transpiration per unit leaf area is 1.99mm·d-1.For White elm tree,the daily average sapflow is 4.08L·d-1,while the daily average transpiration per unit leaf area is 0.49mm·d-1.The values for Mongol Scotch Pine are 3.91L·d-1 and 0.25mm·d-1,respectively.In the total 73 days of observation during the growing season at the Erjinaqi site, the daily average sapflows of Russia olive and Euphrates Poplar are 12.1 and 20.97L·d-1,respectively,and the average transpirations per unit leaf area are 0.22 amd 0.31mm·d-1,respectively.In the observation period of the growing season,tree conductances of Mongol Scotch Pine, White elm, Gansu Poplar or Russia olive show an exponential relationship with the daily average air temperature or vapour pressure deficit, but the relationship is not so obvious between tree conductance and global radiation. The transpiration process of each tree species is affected by all the observed four environmental variables. The response of tree conductance to different climatic factors changes with tree species. The effect of the same factor to the same tree species is also variable in different growing stages. The sapflow of every tree species is relatively large in later spring to early summer, and low in summer, and then reaches its largest value in later September. In the mid-November, the sapflow is relatively large, especially the deciduous tree species. This may be characteristic of the tree species in Arid Regions of Northwest China.  相似文献