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1.
The north-south trending Kullu valley between Rohtang in the north and Hansu in the south is a wide and open valley filled with Quaternary sediments along the main course of the Beas River. The valley in the middle is drained by the Beas River and numerous tributaries join it laterally. The tributary channels have deposited large alluvial fans at their mouths which form three distinct levels. The Beas River has deposited alluvial terraces, which are very distinct towards the lower reaches and form three to four levels. The upper slopes and high altitudinal areas are covered with periglacial and glacial deposits. The terrace, fan and hill slopes have provided an ideal geoenvironment for human activities including agriculture, horticulture, dense settlements and other civil establishments. The Kullu Valley is prone to various natural hazards, flash floods and cloudbursts that are very common in this valley due to its peculiar geomorphic condition, high relief of peripheral ridges and impact of monsoon winds. The studies carried out so far indicate that the losses caused by these phenomena both in terms of life and property are mainly due to unwise human interaction with the geoenvironment of the area. The paper gives an overview of the geoenvironmental status of the Kullu Valley and suggests the necessity of undertaking further detailed studies including resource mapping for balanced development of the area.  相似文献   

2.
Lanzhou-Minhe Basin is situated on the middle Qilian orogenic belt. Yanguoxia Formation contains abundance of maroon siltstones, mudstones and red sandstones of the lake facies. These sedimentary rocks recorded the process of the tectonic uplift of Qilian Mountains during the Early Cretaceous. We discovered plentiful dinosaur footprints, worm burrows, bird footprints, worm tracks-trails, ripple marks and cross lamination in the Yanguoxia site. Integrated petrographic studies classified sandstones of Yanguoxia Formation as feldspathic litharenite. All plots in the QFL (Q or Qt, total quartz; F, feldspar; L, lithic grains) and QmFLt (Qm, monocrystalline quartz; Lt, lithic grains plus polycrystalline quartz) diagrams fall in the recycled orogen provenance field and quartzose recycled field, respectively, implying the source occurred the tectonic activity. Furthermore, geochemical study indicates that the Yanguoxia standstone was formed in an unstable continental setting due to the northwards movement of Indian Plate triggered the collision between the Qilian fold belt and the Qinling fold belt. These sediments were derived from a mixed source and then deposited in the Lanzhou-Minhe Basin. Most of the felsic components were derived from the granitoid rocks of the Qilian Mountains due to the rapid and intense uplift during the Early Cretaceous while the mafic components were contributed by the basic and ultrabasic rocks of the rapidly rising ophiolite in the Qilian Mountain area. Bivariant log-log plot of Qp/(F+L) (Qp, polycrystalline quartz) against Q/(F+L) shows that Yanguoxia Formation was deposited in the semi-humid and semi-arid. Moreover, the pollen also exhibits that the environmental condition during the deposition of Yanguoxia Formation was warm and wet, which affirm such environment was benefit to dinosaur survival. Geochemical study also infers that the Yanguoxia Formation was deposited under the oxidizing condition in a shallow marine environment. The minerals identified from the X-ray diffraction (XRD) analysis of shale and siltstone samples are 4.74%-33.53% clays, 23.45%-4l.70% carbonates and 33.99%-71.81% quartz, respectively, which infer that depositional conditions remained uniform during the formation of shales or siltstones of Yanguoxia Formation.  相似文献   

3.
法治是合法性和合理性的有机统一。作为一项推进依法治国的措施,人民监督员制度只有通过制度的法律化获得存在的合法性,通过组织的社会化获得运行的合理性,通过机制的程序化实现法律化与社会化的现实统一,才能充分符合法治精神,具备监督资格和能力,进而发挥监督实效。  相似文献   

4.
利用岩心、测井、录井、地震等资料,应用层序地层学与沉积学理论,建立博兴洼陷深洼区古近系沙河街组三段中亚段层序地层格架,识别沉积相类型,揭示研究区沙河街组三段中亚段湖底扇砂体的充填期次和规律.结果表明:沙河街组三段中亚段地层划分为2个三级层序,层序内部细分为6个体系域;识别湖底扇中扇、湖底扇外扇、深湖3种沉积亚相,以及辫状水道、水道间、席状浊积岩、远源浊积岩和深湖泥5种沉积微相;总结各沉积微相在岩心、测井、地震上的识别特征;在层序格架内识别各体系域沉积相平面展布规律.此研究对该区下一步油气资源的勘探开发具有指导意义.  相似文献   

5.
冬季,不是只能呆在屋子里,守着暖气和火炉,而今的时尚是顶风冒雪去体验寒冷的乐趣,享受寒冷带给人的美感和刺激。旅游、滑雪能够让您在北国风光中领略大自然,然而这也并不是惟一的选择,旅游,滑雪之余您也可以去狩猎。  相似文献   

6.
A new species belonging to the genus Haloschizopera Lang,1944(Copepoda,Harpacticoida,Miraciidae,Diosaccinae)was identified based on the samples collected from the East China Sea,near the offshore of Zhejiang Province,East China.The new species is closely related to H.pygmaea Norman Sccot T.,1905 and shares a combination of the following features:A1 eight-segmented;A2 exp-2 with one distal seta,exp-3 with three setae;P1 endopodal segments subequal,enp-1 not exceeding exp-2;exp-3 of P3 with one inner seta,of P4 with two inner setae.The new species is characterized by the presence of one inner seta on P2 exp-3 of both sexes.It can also be distinguished from its congeners by the characters of female:P5 exopod subcircular,endopodal lobe extending beyond half-length of exopod;genital doublesomite ornamented with three dorsolateral rows of spinules on anterior part.  相似文献   

7.
In arid regions, mountains fulfill important ecological and economic functions for the surrounding lowlands. In the scenario of global warming, mountain ecosystems change rapidly, especially in the arid region of northwestern China. This paper provides an assessment of the changes in temperature and precipitation in the historical records of climate on the northern slopes of the eastern Tianshan Mountains. A Mann-Kendall nonparametric trend and Sen's tests are employed to analyze the interannual changes and innerannual variability in temperature and precipitatiofi in the regions of low to high altitude. The present study finds that the largest increases in annual temperature are observed at stations in the low altitude regions. The significant increasing trends in temperature tend to occur mainly in late winter and early spring at stations from middle to high altitude, but in summer and autumn at stations of low altitudes. The increasing trends in annual precipitation are found from the middle to high altitude areas, but decreasing trends are found in the low altitude areas. The significant increasing trends in precipitation occur mostly in winter and earlier spring at stations from the middle to high altitudes, while the increasing and decreasing trend coexists at stations of low altitude with most of the significant trend changes occurring in March, June and August.  相似文献   

8.
采样测定了湖南澧水下游表层沉积物21个样品的稀土元素地球化学含量,分析了稀土元素组成特征,据此探讨其物质来源。结果表明:澧水下游表层沉积物中稀土元素总含量为(109.12~192.27)×10-6,平均为148.37×10-6;与湖南土壤背景值相比较,澧水下游表层沉积物含量处于略偏低水平;21个样品的稀土元素含量变化规律高度一致,组成特征变化较小;稀土元素组成表现为轻稀土元素相对富集而重稀土元素相对亏损,Eu呈中等程度亏损,Ce呈弱的负异常;澧水下游表层沉积物的稀土元素总含量、特征参数,与湖南土壤、长江沉积物背景值比较接近,其大陆上地壳标准化和球粒陨石标准化稀土元素配分模式与长江沉积物很接近,这可能暗示了澧水下游表层沉积物除了主要来源于澧水河流侵蚀搬运物外,部分可能来源于松滋口、太平口和藕池口等荆江3口泄洪带入的长江沉积物。  相似文献   

9.
Monthly investigations were mae on the population of Chinese freshwater crab,Sinopotamon yangtsekiense Bott, 1967 from April, 1984 to March, 1985. The data on 4413 specimens show that the growth was affected mainly by temperature. During the April to November growth period, the crabs' major development occurred from June through October. One year was required for a fine white oocyte to develop into a mature egg. The reproduction period was June–October. Females bearing eggs were taken from June–August, and crabs with young were found from July–October. The females reproduced once a year but could for more than one year. The number of eggs carried by a female varied greatly according to the size of the crab, ranging from 30 to 100 eggs. New-born crabs become mature after 1–2 years. The sex ratio was approximately 1∶1 in the overall population. However, the larger crabs are predominantly male. The age distribution ofS. yangtsekinese was estimated from size frequency histograms. There were more adult crabs (over 70%) from June to October and more immature crabs (over 50%) from November to May.  相似文献   

10.
Han  Jinfen  Nan  Fangru  Feng  Jia    Junping  Liu  Qi  Liu  Xudong  Xie  Shulian 《中国海洋湖沼学报》2022,40(2):729-744
Journal of Oceanology and Limnology - The genus Sheathia consists of over 20 species primarily distributed in Asia, Europe, Oceania, North America, and Africa. However, the origin and evolution of...  相似文献   

11.
The species composition and abundance of microzooplankton at 10 marine and five coastal stations(Hongdao,Daguhe,Haibohe,Huangdao and Hangxiao) in the Jiaozhou Bay(Qingdao,China) were studied in 2001.The microzooplankton community was found to be dominated by Tintinnopsis beroidea,Tintinnopsis urnula,Tintinnopsis brevicollis and Codonellopsis sp.The average abundance of microzooplankton was highly variable among stations.Specifically,the abundance of microzooplankton was higher at inshore stations and lower ...  相似文献   

12.
The Bamsk gold-ore deposit is located in the Amur region, the Far East of Russia. It is confined to the Early Cretaceous volcanic-plutonic uplift of central type, located in the Stanov folded-clumpy Pre-Cambrian system. The deposit is presented by a series of gold-bearing quartz and carbonate-quartz vein-stringer zones. They are confined to the super-intrusive zone of the Nevachansk subvolcanic intrusion of sienite-porphyric composition. The mineralization is being controlled by zone of fractures developed in the autochthone ofthe Bamsk fault. Quartz, carbonates and sericite prevail in the composition of ores. The quantity of ore minerals doesn't exceed 1%~5%. Pyrite, chalcopyrite, galena and native gold are widely spread. Sheelite, gold and silver tellurides, sulphobismuthites, acanthite, sphalerite and cinnabar are less developed. Four stages of mineralization have been distinguished. Gold-sulphide-sulphosalt ore with tellurides of gold and silver is productive for gold. The following set of elements is typomorphic for the ores of the deposit: Au, Ag, Cu, Bi,Mo, Pb and Sb (W1, Pb1, Mo) -Cu- (Ag, Bi, Sb, Mn, W1, Pb2) form the vertical series of zoning. Rocks, enclosing the mineralization are exposed to the processes of listvenitization-beresitization. The processes of gumbeization and argillization are less manifested. The age of the gold mineralization, determined by Rb-Sr method on ore-accompanying minerals, is 130.6 Ma.  相似文献   

13.
准噶尔盆地玛湖凹陷下三叠统百口泉组的沉积背景分析表明,研究区存在东西2个方向的6个分支物源,古凸起及沟槽对水系具有分隔控制作用,控制砂体沉积。通过岩心观察,归纳总结出9种岩相,结合录井、测井资料分析,认为玛湖凹陷下三叠统百口泉组沉积相类型主要为扇三角洲相,并详述了7种微相的沉积特征。利用地质地震资料综合分析,确定出玛湖凹陷百口泉平面沉积特征,凹陷内发育6个受物源控制明显的扇体,相邻扇体在平原相带被凸起带分隔,在前缘相带内相互交汇叠置。   相似文献   

14.
The Bamsk gold-ore deposit is located in the Amur region, the Far East of Russia. It is confined to the Early Cretaceous volcanicoplutonic uplift of central type, located in the Stanov folded-clumpy Pre-Cambrian system. The deposit is presented by a series of gold-bearing quartz and carbonate-quartz vein-stringer zones. They are confined to the super-intrusive zone of the Nevachansk subvolcanic intrusion of sienite-porphyric composition. The mineralization is being controlled by zone of fractures developed in the autochthone of the Bamsk fault. Quartz, carbonates and sericite prevail in the composition of ores. The quantity of ore minerals doesn‘t exceed 1% ~ 5%. Pyrite, chalcopyrite, galena and native gold are widely spread, Sheelite, gold and silver tellurides, sulphobismuthites, acanthite, sphalerite and cinnabar are less developed. Four stages of mineralization have been distinguished. Gold-sulphide-sulphosalt ore with tellurides of gold and silver is productive for gold. The following set of elements is typomorphic for the ores of the deposit: Au, Ag, Cu, Bi, Mo, Pb and Sb (W1, Pb1, Mo) -Cu- (Ag, Bi, Sb, Mn, W2,, Pb2) form the vertical series of zoning. Rocks, enclosing the mineralization are exposed to the processes of listvenitization-beresitization. The processes of gumbeization and argillization are less manifested. The age of the gold mineralization, determined by Rb-Sr method on ore-accompanying minerals, is 130.6 Ma.  相似文献   

15.
Two nematode species of the genusDorylaimopsis (Family Comesometidae) from the Bohai Sea are described.Dorylaimopsis rabalaisi n. sp. similar toD. punctata Ditlevsen, 1918 from which it can be separated by the small size, short and simple spicules without ventral apophyses or joint line.Dorylaimopsis turneri n. sp. differs from the closest speciesDorylaimopsis angelae (Inglis, 1967) by its higher values of de Man ratio ‘a’, much shorter spicules and higher ratio of gubernacular to spicules length. A key to species of the genus based on the key by Jensen (1979) is given. This project was supported by the National Science Foundation, No: 3860804  相似文献   

16.
首先,我代表徐冠华部长,代表科学技术部向这次研讨会和产业园的奠基表示衷心祝贺,向各位来宾表示亲切问候。  相似文献   

17.
With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-weight relationship,age composition,growth pattern,mortality,and exploitation rates of the yellow goosefish in the Yellow Sea.Total length(TL) of females and males ranged from 173 to582 mm and 178 to 500 mm,respectively.The length-weight relationships were also estimated for females and males.Age classes from 2 to 4 years predominated in the samples.The von Bertalanffy growth function(VB GF),estimated based on non-linear least-squares methodology,showed significant differences between sexes.Females attained a greater estimated asymptotic total length(765 mm TL) compared to males(579 mm TL).The VBGF did not differ significantly between stocks of the northern Yellow Sea and the southern Yellow Sea.Estimated natural instantaneous mortality rate(M) ranged from 0.25/a to 0.33/abased on four age-and length-based methods.Total instantaneous mortality rate(Z) of total samples calculated by the age-based catch curve method was 0.591/a and the average fishing mortality(F) was 0.30/a.Estimated exploitation rate(E) was approximately 0.5,indicating that the population of L.litulon in the Yellow Sea may be sustainable.These results provide a reference for the present status of L.litulon and information for the management.  相似文献   

18.
湖南邵东县石桥铺铅锌矿是产于岩体构造破碎带中,属中—低温热液裂隙充填型矿床,位于关帝庙穹窿内,成矿时代为新华夏系。目前该矿区的一号断裂带、四号断裂带和九号断裂带中的局部地段发现有铅锌矿体和矿化体。岩浆期后的断裂带为后期矿体的形成提供了有利的矿液运移通道和储矿空间;新华夏系断裂控制着本矿区内矿体的形态、大小、产状等,是矿区内的主要控矿、容矿构造。且矿体具有明显的垂直分带特征,上部主要为萤石矿、重晶石矿,中、下部为铅锌矿。本文根据矿体地质特征、变化规律,分析矿床成因,总结找矿标志,为矿区找矿前景进行探讨和分析,为外围找矿提供思路。  相似文献   

19.
The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0.  相似文献   

20.
Photo-protective functions were investigated in phytoplankton assemblages at Kongsfjorden, Svalbard in spring, using their UV-absorbing compounds (mycosporine-like amino acids (MAAs)), xanthophyll pigments (diadinoxanthin (DD) and diatoxanthin (DT)) and < beta >- dimethylsulphoniopropionate (< beta >-DMSP). The dominant phytoplankton species in the inner bay were dominated by Phaeocystis spp. and nanoflagellates, while the offshore waters were dominated by Thalassiosira spp. In the inner bay, UVabsorbing compounds and xanthophyll pigments exhibited higher ratios of MAA to chlorophyll a (MAA:chl a ratio), and both DD and DT to chlorophyll a (DD:chl a ratio and DT:chl a ratio), respectively. Thus, the photoprotective-pigments such as DD and DT appear to complement MAAs in the natural phytoplankton assemblage. However, the ratio of < beta >-DMSP to chlorophyll a (< beta >-DMSP:chl a ratio) did not show a distinct spatial distribution according to environmental factors or interspecies differences. In this study, we found that photoprotective compounds occurred in a manner dependent on the phytoplankton species composition in Kongsfjorden Bay, where Phaeocystis is the dominant species.  相似文献   

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