四川省酉阳土家族苗族自治县经济综合开发的新设想     

邹明星 《山地学报》1992,(3)

地处武陵山区的酉阳土家族苗族自治县,是国家重点扶贫县之一。要在“八五”期间稳定群众温饱、迅速脱贫致富,必须坚持山区经济的综合开发,即系列开发抓支柱、科学开发抓普及,规模开发抓集约、立体开发抓庭院。  相似文献   

利用NOAA卫星资料解译哀牢山区日照场的研究     

张养才  叶一舫  曹高生  潘钟跃 《遥感学报》1992,(4)

首次应用NOAA卫星的AVHRR资料提取天空云遮蔽信息。以多时次可见光波段反射率平均值与相应月份的日照时数建立回归方程,解译哀牢山区日照场时空分布特征。它具有空间分辨率高、资料信息量多,并客观地反映在坡向、坡度、河谷、平坝等复杂地形及不同植被等综合影响下的光资源的时空分布规律,为深入研究山区光资源提供新的方法和科学数据。  相似文献   

基于OLI和DEM数据初步研究盘谷寺断裂新构造运动特征     

马兴全  王志铄  张扬 《震灾防御技术》2020,15(2):359-368

太行山南缘盘谷寺断裂新构造运动特征对分析太行山地区构造地貌演化，乃至研判我国东部新构造活动形势具有重要意义。基于Landsat 8 OLI遥感影像数据和ASTER GDEM数据，对盘谷寺断裂线性构造进行初步解释，分析冲沟发育、坡向坡度等构造地貌特征，通过构建遥感影像与高程数据相叠加的三维地貌模型，进一步优化断裂构造地貌视觉效果。研究结果表明，盘谷寺断裂为1条平面呈舒缓波状、近东西走向的南倾正断层。在断裂下盘，由西向东依次发育了密集的平行状侵蚀沟、断层三角面和低矮的侵蚀残丘等多种构造地貌类型，反映了断裂不同部位垂向运动的差异性。构造运动导致断层两盘地表坡向和坡度的明显变化，综合剖面分析结果，认为断裂在新构造期活动强度由西向东逐渐减弱。  相似文献   

论造山作用和造山带   总被引：15，自引：2，他引：13  

杨巍然 《地质论评》1999,45(1):10-14

造山作用和造山带是地学界广泛使用的名词,但不同学者对它们的理解不尽一致,特别是在与成山作用和山脉的关系上出现混淆现象。造山作用,造山带和成山作用,山脉是两组既有联系又有区别的概念,后者是自然地理名词,前者是构造名词,而且限于挤压作用所形成的构造现象和过程。根据这种理解,笔者将造山带划分为俯冲－碰撞造山带,断裂造山带,推覆造山带,断块造山带,增生造生和转换造山６种类型。  相似文献   

贵州修文红黄铝土矿地质地球化学特征及成因意义          下载免费PDF全文

吴波  邓克勇  刘应忠  胡荣  覃红亮  陈启飞  徐安全  黄欣欣 《贵州地质》2020,37(2):144-153

红黄铝土矿位于黔中修文铝土矿成矿带,矿体产于石炭系下统九架炉组,呈似层状、层状产于寒武系中-上统娄山关组白云岩之上,石炭系下统摆佐组灰岩之下,矿床成因类型为古风化壳沉积型。矿石自然类型以碎屑状为主。含铝岩系中主量元素以Al_2O_3、SiO_2、TFe_2O_3及LOI(烧失量)为主,BaO、K_2O、Na_2O、P_2O_5等含量相对较低, SiO_2、TFe_2O_3与Al_2O_3呈不显著的负相关关系,TiO_2与Al_2O_3呈显著的正相关关系;微量元素Zr、Sr、V、Li、Ga、Sc等含量相对较高,Sn、Ta、W、Be、Pb、Cs等含量相对较低;环境敏感要素Th含量及Th/U比值表明铝土矿主要形成于半咸水-淡水沉积环境,成矿作用可能是由沉积混杂和风化沉积作用形成;Sr/Ba比值表明铝土矿经过海陆交互沉积。含铝岩系中ΣREE值较高,ΣLREE/ΣHREE比值为1.4■5.71,表现为轻稀土比重稀土富集,具有δEu负异常、δCe异常不明显的特征。含铝岩系Ce/Ce*=1.0■2.8,平均1.91,表明含铝岩系主要形成于富氧的沉积环境。综合研究表明,本区寒武-奥陶系碳酸盐岩为铝土矿提供了丰富的成矿母质,古喀斯特岩溶盆地为铝土矿沉积提供了有利场所和剥蚀风化条件,后期构造作用和风化淋滤作用造成硅铁流失和铝的富集,最终形成优质铝土矿床。  相似文献   

The paleolimnological analysis of sediments from high mountain lake Nižné Terianske pleso in the High Tatras (Slovakia)     

F. Šporka  E. Štefková  P. Bitušík  A.R. Thompson  A. Agustí-Panareda  P.G. Appleby  J.A. Grytnes  C. Kamenik  I. Krno  A. Lami  N. Rose  N.E. Shilland 《Journal of Paleolimnology》2002,28(1):95-109

Sedimentological climate proxies and a 200-year long climate record, reconstructed using a data-set of European-wide meteorological data, have been compared at the high mountain lake Niné Terianske pleso in the High Tatras, Slovakia. Diatoms, chrysophyte stomatocysts, chironomids, plant pigments and spheroidal carbonaceous particles (SCPs) were analysed as well as sediment lithostratigraphic parameters. Using a radiometric approach the sediment core was dated and a depth of 4.6 cm was found to correspond to 1852 AD. The sediment accumulation rate (0.0034 g·cm^–2·yr^–1) was one of the lowest identified in the European mountain lake project, MOLAR. Despite this slow accumulation rate a remarkably coherent lithological and stratigraphic record has been recovered. The sediments of this remote mountain site, largely free from the effects of direct human impact, have been found to display a wealth of variability over the last 200 years.The record of spheroidal carbonaceous particles, indicators of anthropogenic pollution deposition, begins around 4.5–5.0 cm in depth (1833–1857). Temporal patterns are typical of European lake sites with the concentration peaking in the late 1970's. The SCP/²¹⁰Pb inventory ratio for the site is also in good agreement with the European latitudinal pattern. A strong influence of sample age on the chrysophyte assemblage composition in the upper-most 4–6 cm indicates that the main changes in the cysts have been related to long term environmental changes, probably pH. Analysis of chironomid remains revealed a stable profundal community. Chironomids as a whole showed no correlations to temperature fluctuations in the last 200 years. Relatively abundant remains of Diamesa sp. head capsules and other taxa closely associated with stream conditions in the older layers contrast with the absence of Diamesa sp. in the recent sediments. This change is considered to be evidence for the existence of a stronger, more stable inlet supplied from permanent granular snow fields in the lake basin. The most important changes in diatom assemblages were observed at 3cm. Many species of the genus Achnanthes spp. together with Navicula schmassmannii and Orthoseira roeseana made up the greatest part of the diatom community above 3 cm, being absent or rare lower in the record. A positive correlation between diatoms and mean summer temperature was found.  相似文献   

Lake Jezero v Ledvici (NW Solvenia) – changes in sediment records over the last two centuries     

Anton Brancelj  Milijan Šiško  Gregor Muri  Peter Appleby  Andrea Lami  Ewan Shilland  Neil L. Rose  Christian Kamenik  Stephen J. Brooks  John A. Dearing 《Journal of Paleolimnology》2002,28(1):47-58

Lake Jezero v Ledvici (NW Slovenia) is a 14 m deep mountain lake at an elevation of 1860 m, situated on limestone bedrock. It is an oligotrophic, alkaline and hard-water lake with a transparency of about 14 m and has suffered several times over recent centuries from strong earthquakes. In 1996 five sediment cores, between 35 and 45 cm long, were collected from the deepest part of the lake and analysed to reconstruct environmental changes over the last few centuries. The data indicate changes induced by pollution and climate change during the last two centuries similar to those in other European mountain and remote lakes. However, at this site earthquakes have also affected the lake and partly obscure the interpretation of the sediment record. From 1780 to 1890, sediment records show low abundance of diatoms and relatively high abundance of Cladocera. After 1890, the number of diatoms started to increase coinciding with a strong earthquake. From the beginning of the 20th century, concentrations of spheroidal carbonaceous particles (SCP), diatom valves and head capsules of chironomids gradually increased whilst in Cladocera the main difference observed was a change in the proportion of benthic taxa. After 1960, in parallel with a rise in air temperature, a further increase in accumulation rate of diatoms started, but there was a decrease in Cladocera.  相似文献   

国外景观演化研究的最新进展   总被引：5，自引：0，他引：5  

程绍平  李传友  杨桂枝 《地学前缘》2003,10(Z1):31-37

景观演化与全球构造、生物演变和主要气候变化具有相同的时间尺度 ,是长期全球变化的一个重要方面。最近 ,地表过程在地壳变形中的作用已经引起了广泛的注意 :一方面努力从景观中模拟地形演化或演绎地壳过程 ;另一方面试图通过地壳变形和地表过程的型式和速度来研究隆起、海平面变化、侵蚀、气候和地势之间的动力学关系。文中旨在介绍和评述国外关于会聚边缘和裂开边缘山脉尺度景观演化研究 ,包括高原边缘地形演化、前陆盆地的沉积型式、景观切割、古地形复原以及质量流动和平衡等方面的最新进展 ,以及地表过程和地壳过程相互作用中的反馈机制、均衡效应和岩石圈强度效应以及调整和平衡等几个理论问题。目前已经普遍认为 ,把地表过程纳入地球动力学模型之中 ,无疑对于认识造山带的发育和裂开边缘的演化是一个巨大的进步。  相似文献   

山区河流平面二维流场的数值模拟   总被引：11，自引：0，他引：11       下载免费PDF全文

李艳红  周华君  时钟 《水科学进展》2003,14(4):424-429

针对山区河流边界地形复杂、水位及流速变化剧烈的特点,用"混合五对角法"建立平面二维数学模型并求解,进行水位和流速的数值模拟.利用嘉陵江重庆金刚碑-朝阳桥河段地形及5个横断面的水位和水深平均流速资料对此模型进行了验证,模型快速、准确地再现了该河段的水位和水深平均流速情况.  相似文献   

新疆西天山莫托沙拉铁(锰)矿床与式可布台铁矿床地质特征对比   总被引：3，自引：0，他引：3       下载免费PDF全文

袁涛 《地质找矿论丛》2003,18(Z1):88-92

新疆西天山富铁矿成矿带位于伊犁板块东端,火山岛弧带弧间断陷盆内.文章详述了莫托沙拉铁(锰)矿床、式可布台铁矿床的地质特征,讨论了矿床成矿机制,对矿床的共性和个性进行了对比.认为铁质来源于海相火山喷气,海解萃取,高密度流体运移,同生断裂提供热液,贮矿盆地下陷接受沉积,最终呈向斜构造.  相似文献