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1.
This research paper analyses the grain-size characteristics of the Quaternary deposits at Xingshan near Siping, Jilin province in China by employing graphic measures to study the grain size distribution and its mode of transport and deposition. The Quaternary deposits at Xingshan lie unconformable on Cretaceous rocks made of siltstone, mudstone and sandstone. The average grain size is between 8.06 to 8.55Φ (0.002 6 ~0.003 7 mm). The Quaternary deposits at Xingshan mainly compose of very fine silt to clay. The compositions of the grade are clay 63% and silt 37%. The clay size components are weathered debris transported and deposited by flowing water from the SE highlands or hills to the low lying NW Xingshan plains whereas the silty components accumulated by aoelian process. The Quaternary deposits at Xingshan accumulated in the middle and late Pleistocene interglacial periods from (459.12~39.03) ka to (88.92~7.56) ka. The standard deviation ranged from 0.96 to 1.36Φ, indicating that the sediments are moderately to poorly sorted, Coefficient of skewness ranged from 0.16~0.31 with an average skewness of 0.218, (Positively skewed towards fine). Kurtosis values (0.84~1.05) from the grain size distribution and visual inspection of the frequency curves indicate platykurtic to mesokurtic curves and unimodal to bimodal grain-size distribution. The type of deposit formation is sand dune and the source is at a distal from its provenance.  相似文献   

2.
On the basis of field survey, microscope sighting, TL dating and scanning electron microscope analysis, the characteristics of Quaternary deposits near Songjianghe Town on the west slope of Changbai Mountain are analyzed and described. There were two phases of volcanism during Mid-Late Quaternary. One occurred before 15.22 × 104 aB.P. and the other happened between 14.27 × 104 aB.P. and 1.41 × 104 aB.P. Volcanism is a landform-making process which makes the rough relief in the studied area become higher and higher. Flow water is a main erosion agency and it cuts into the basalts making river valleys. The Quaternary fluvial deposits distributed on terraces first come from the weathered debris of basement rocks, then they are transported and deposited by flow water. After 1.41 × 104 aB.P, the river water quickly cuts into the newly formed basalts making a deep valley. Volcanism in the studied area is a main landform-making event in Mid-Late Quaternary.  相似文献   

3.
1GeologicalsettingThe researched area is located at the east margin of Eurasia plate and is 50 km from Changbaishan Vol-cano to west. The average elevation of the studied area is about 1 200 m and rivers flow mainly from the east to the west. There are To…  相似文献   

4.
采用MS2000型激光粒度分析仪进行测试,利用计算机粒度分析软件对数据进行整理和计算,绘制出样品的频率曲线、概率累积曲线以及粒度众数位值曲线等图件并进行沉积环境分析。厦门地区第四纪环境演化经历了中更新世同安组(含泥中粗砂、含泥细中砂、砂为主)海积一冲积一更新统上部龙海组(含泥粗中砂、含泥细中砂、含泥粗砂、粗砂、细中砂、含细砾中粗砂、中细砂等)冲积一洪冲积一更新世上部东山组(砂、砂砾、含泥中粗砂、粗砂、泥质中细砂、细砂、中粗砂等)冲洪积及部分海积(粉砂、细粉砂、含碳质泥、粘土、淤泥质粘土、粉砂质粘土等)一全新世长乐组(粉砂,淤泥质粘土、粉砂质粘土、碳质粘土、含砂淤泥质粘土,粉砂质亚粘土、粉细砂亚粘土等)海湾沉积。在解释环境变化的同时,说明粒度变化曲线在一定程度上可以作为地层划分的依据之一,并以此对研究区地层进行了详细划分。  相似文献   

5.
Features of Sand-dust Deposits in Harbin City, China   总被引:1,自引:0,他引:1  
1 Introduction The sand-dust storm weather, induced by special at- mospheric circulation in specifically geologic and geo- graphic environment, is disastrous one with little prob- ability and excessive harm. In China, the sand-dust storm frequency of every 10 years had increased from 4 times in the 1950s to 23 times in the 1990s (Zhuang et al., 2001). The sand-dust weather occurring in a large area of the northern China in the spring of 2002 had attracted much attention. People are gradually…  相似文献   

6.
Therearemanyquaternaryglaciallandformsinalpineareasahave3100ma.s.1.intheGongWangMountainsinthenortheastpartofYunnanProvinceofChina.TheglaciationseriesandtheglaciallandformsoftheQuaternaryhaveoncebeencoveredinanarticlesketchily(Yietal.,1991).Onthebasisoffieldinvestigationsinrecentyears,we'11goastepfurthertodiscusstheQuaternaryglaciationseriesandtheglacierlandfo~sthereinthisPaper.I.TabsQU~ANANYG~W~TheGOngWangMountainsissituatedbetweentwobranchesoftheJinshaRiver,theXiaojiangandthePudu…  相似文献   

7.
Based on the monthly mean temperature, the changing processes and tendencies of temperature during1951 -2000 in Jilin Province, which is in Northeast China, are analyzed. And the spatial characteristics of the changeare submitted. In the past 50 years the temperature of Jilin Province was increasing just like the other areas in the world.Since 1990, the increasing of temperature has been more obvious than that in the previous 40a. From the west to theeast, the province has larger temperature rising. According to Principal Component Analysis (PCA) of temperature field,Jilin Province is divided into 3 regions and the degree of becoming warmer is different from region to region. During theperiod of 1951 to 2000, the annual temperature in Jilin Province has been rising, so has the temperature in winter andsummer. The average temperature in the 1990s was 0. 5 - 2. 0℃ higher than that in the 1950s. From the west to theeast, the increasing of temperature became smaller.  相似文献   

8.
The Xiaohongshilazi mineral deposit in Jilin Province,China,is located in the accretion zone in the northern margin of the North China Block. The deposit contains two types of ore bodies: layered Pb-Zn ore bodies in volcanic rock and vein-hosted Pb-Zn ore bodies controlled by fractures. The vein Pb-Zn ore bodies are strictly controlled by tectonic fracture zones trending in S-N direction,which comprise sulfide veins or sulfidebearing quartz veins distributed along faults or structural fissures. The ores mainly appear mesh-vein and vein structures,and also show solid-solution separation and metasomatic textures. The metal minerals are mainly sphalerite,galena,and pyrite,etc. Wall-rock alteration includes mainly sericitization,chloritization,silicification and carbonatization,etc. Microscope observations and Raman spectroscopy analyses indicate that the oreforming fluid of the vein Pb-Zn ore bodies was mainly magmatic water with low temperature,low salinity,and a shallow depth of metallogenesis( ~ 1.5 km). Sulfur and lead isotope analyses indicate that the sulfide source is mainly formation sulfur or biogenic sulfur,which is similar to the sulfur source of hydrothermal deposit( negative( δ~(34) S values),while the main Pb source was the upper crust with some mantle input. This article argues that the vein Pb-Zn ore body of the Xiaohongshilazi deposit is a low-to medium-temperature hydrothermal vein type related to the formation of a shallow magma chamber.  相似文献   

9.
A field investigation on Quaternary glacial landforms in Laoshan Mountain has discovered many glacial potholes, scouring grooves on top of granite ridges, and large boulders. These erosional landforms were formed by the meltwater from the overlying ice cap, suggesting that there was at least an ice cap covering Laoshan Mountain and the surrounding areas or even a continental ice sheet over the vast area of Shandong Province in the Late Pleistocene. The ice sheet was obstructed by the Laoshan Mountain, Dazhu Mountain and Xiaozhu Mountain in the coastal areas as it moved toward the Yellow Sea. The ice flows eroded the bedrock and carved the weak intersection of the fault systems in the NE and NW directions into a deep channel, which gradually formed a fjord in the area of the Jiaozhou Bay basin by 20.00 ka BP. The seawater gradually invaded the fjord from the beginning of the Holocene (11.00 ka BP) and Jiaozhou Bay was eventually formed. Similar fjords are easily found along the east of China and they share a similar origin because of the Quaternary glaciation in the region.  相似文献   

10.
The TMS5e sequence from the Tumen section,at the southern edge of Tengger Desert in the northwestern China,is synchronous with Marine Isotope Stage 5e(MIS5e).It consists of 16 layers of aeolian dune sands,11 layers of lacustrine loess-like facies,and 5 layers of lacustrine facies.The results of grain-size analysis shows that the palaeo-mobile dune sands,palaeo-fixed to semi-fixed dune sands and loess-like sandy loams are mainly composed of sands,ranging from 70% to 96%;their silt contents ranged from 4% to 20%,and their clay contents ranged from 1% to 5%;the climate under which the aeolian dune sands were deposited is similar to that under which modern mobile dune sands form,which is caused by the dominance of the cold,dry East Asian winter monsoon.In contrast,the lacustrine loess-like facies and lacustrine facies had a lower sand contents than those of the three aeolian dune sands,but have higher silt and clay contents,most of their sand content ranged from 30% to 60%,their silt contents ranged from 35% to 55%,and their clay contents ranged from 6% to 20%.The lacustrine loess-like facies and lacustrine facies formed under the influence of the warm,humid East Asian summer monsoon based on their similarity with modern sediments.The grain-size indicator Mz(mean grain diameter) and the SC/D value in the TMS5e sequence indicate climatic insta-bility at the southern edge of the Tengger Desert during MIS5e,with at least 14 fluctuations between a warm,humid climate and a cold,dry climate,divided into five stages:TMS5e5(139 kyr to 129.3 kyr B.P.),TMS5e4(129.3 kyr to 124 kyr B.P.),TMS5e3(124 kyr to 119.5 kyr B.P.),TMS5e2(119.5 kyr to 116.5 kyr B.P.),and TMS5e1(116.5 kyr to 113.7 kyr B.P.).These correspond roughly to MIS5e5,MIS5e4,MIS5e3,MIS5e2,and MIS5e1,respectively,in the GRIP ice core data.  相似文献   

11.
The grain-size distribution characteristics and grain-size parameters of sediment in two vertical sections of Daniugou peatland in the Changbai Mountains were systematically investigated. A comparative analysis of the sediment granularity using a discriminative function with Hongyuan peat, red clay, loess-paleosol, fluvial deposit as well as lacustrine deposit was also conducted. It turns out that the vertical section of Daniugou peat ash is primarily constituted by clay and silt particles, and the content of sand is relatively small. Grain-size frequency curves generally show a single-peak modality while a bimodal pattern is detected in the upper layer. The grain-size component and peak pattern of grain-size frequency curves also illustrate that peat ash materials were transported to the peatland by long-range aeolian dust during the deposition process, while there existed short-distance dust influence in peat deposition of the upper layer. Comparisons of grain-size parameters and the discriminative Y-value of Daniugou peat ash with those of typical aeolian sediments show close similarities, suggesting the possibility that atmospheric dust transport processes were involved in the accumulation of peat again. Moreover, the variations of grain-size distribution suggest the local environmental deterioration which is just the driving force of local dust elevation. Grain-size analysis of peatland sediment is demonstrated to be one effective method to extract information about regional and global environmental evolution, and more attention should be paid to current local ecological environment and to seeking a balance between economic development and environmental protection in Northeast China.  相似文献   

12.
1Geologic settingThe Shibaqinghao gold deposit is situatedinthemiddle part of Serteng Mountains,Inner Mongolia.Geotectonic placeislocatedinthe western part of thenorthern margin of the North China Craton.Dongwufenzi Group that is the country rocks ofShibaqinghao gold deposit is composed of green-schist-facies metamorphic rocks.According to thestudy(Liuet al,1987),the proto rocks of Dong-wufenzi Group are assumed to be ultramafic volcanicrocks(komatiite),tholeiitic and alkali basalts,sili…  相似文献   

13.
There are two types of gold ore in Shibaqinghao gold deposit, mylonite ore and quartz vein ore. Pyrite accompanying with native gold in mylonite ore has Fe from 43.66 to 45.32 wt% and S from 52.64 to 53.55 wt%. It is clear that this kind of pyrite is poor in both sulphur and iron. That means that the mylonite ore may be related to metamorphic water. Pyrite in the quartz vein ore has Fe from 44.38 to 45.30 wt% and S from 53.08 to 54.00 wt%. It means that this kind of pyrite is poor in iron but rich in sulphur, while the quartz vein ore may be related to magma water.  相似文献   

14.
The Qilishan gold deposit is located in the southern Zhaolai gold ore belt in the northwestern Jiaodong region.A total of seven gold ore bodies have been found in the mining area.Linglong gneissic biotite granite and the NE trending Lingbei fracture control the output and distribution of the gold deposit.The ore bodies with veined or irregular shape occur in the structural alteration zone.The ore bodies of different sizes are NE trending and SE dipping.The constituent minerals of the ores mainly include pyrite,chalcopyrite,native gold,electrum,argentite,matildite,hematite,quartz and calcite.The ores are characterized by metasomatic dissolution structure,as well as veined and brecciated structures.The ore-forming process is divided into four stages,namely quartz-,pyrite-,polymetallic-and carbonate stages.Study on fluid inclusion shows that the deposit is composed of gas-liquid two-phase inclusions (Ⅰ) and three-phase inclusions containing CO2 (Ⅱ),and that the former dominates.The homogenization temperature is 259.6℃-373.7℃ ; the salinity of three-phase inclusions containing CO2is 5.77%-9.84% (NaCl) ; the salinity of gas-liquid two-phase inclusions is 6.58%-8.54% (NaCl) ; and the estimated ore-forming pressure is 55.2-82.2 MPa.According to the nonlinear relationship between the depth and pressure of the fluid in the fracture zone,the ore-forming depth of the Qilishan gold deposit is calculated as 5.95-7.14 km.It is preliminarily determined that the deposit is a mesophilic and hypothermal gold deposit.  相似文献   

15.
Ancient town Dali is located in northwest Yunnan Province. With its ancient history and natural scenery, it is preserved as one of the first 24 historical and cultural towns in China. Dali has become one of the most popular attractions for foreign tourists since it had its first foreign visitors in 1983. As a result, English came into the life of the local people. This paper presents and explains the results of questionnaires and interviews about Dali people’s attitude toward learning English. Three types of questionnaires were designed to local businessmen, local residents and foreign tourists. Interviews were also given whenever possible. In this study, businessmen in Dali were divided into two distinct groups. One group had their business in “Foreigners’ Street”, which was in front of Hongshancha Hotel where many foreign tourists stayed. Another group had business in Fuxin Street, which was vertically across “Foreigners’ Street”. The 41 shops and restaurants in “Foreigners’ Street” served mainly foreign visitors, and most of them had English names and advertisements. The 353 shops and restaurants in Fuxin Street mainly catered for domestic visitors but also served more and more overseas ones. Subjects from local residents were mostly young people because aging ones were apparently not much affected by English. The results of the study showed that the oral English levels became lower from “Foreigners’ Street” to Fuxin Street to local residents, due to declining frequency of contact with foreign people. There were also distinct differences in general English level, the understanding of the importance of English, the purposes of communicating with foreign tourists, the willingness and purposes of going on learning English between businessmen in “Foreigners’ Street” and Fuxin Street: people in “Foreigners’ Street” had more positive feedback than those in Fuxin Street because their constant contact with foreigners required them to speak better English which enabled them to exchange with foreigners in many aspects, which in turn help them to know more about other cultures. On the other hand, Fuxin Street businessmen would catch up with more and more prospective contact with overseas people. Though local residents had nothing to do with foreign tourists, they met them in the street every day and might have to talk with them in unexpected ways. They lived in a place where they saw English advertisement every day. Accordingly, study results showed that they were very much motivated to learn English. They showed even stronger desire to learn more English than businessmen in “Foreigners’ Street”, though many of them were too young to tell why English was so important for them. This is an indication that English has become part of the necessary education for young people in Dali. With the development of tourism, Dali is gradually becoming a place where Chinese culture and western culture meet and coexist. This project was supported by National Natural Science Foundation of China.  相似文献   

16.
本文以灯光密度表征建设用地产出效率,采取KDE、ESDA、SDE等方法对中国县域尺度2000-2015年建设用地产出效率的总体特征、时空演变以及方向分布进行分析,研究发现:① 夜间灯光总亮度与建设用地出产出存在较强的相关关系,说明可用灯光总亮度表征建设用地产出,以灯光密度反映建设用地产出效率具有一定的科学性。② 建设用地产出效率东高西低,持续上升;增长速度西高东低,中部居中,但区域间年均增长率最大相差0.56%,整体较为均衡。③ 虽然建设用地产出效率由2000年的0.008单位灯光/km2持续上升至2015年的0.025单位灯光/km2,但其核密度曲线始终处于中低水平且右侧区间不断扩大,说明中国建设用地产出效率总体水平较低,呈现出中低水平俱乐部收敛的特征。④ 建设用地产出效率的全局 Moran's I指数都大于0,建设用地产出效率存在正向空间分布特征,且其局部空间格局变化较小,存在稳中有动,强中有弱,弱中有强的特点。⑤ 方向分布上,建设用地产出效率的方位角始终在72.420o与81.066o之间,说明东北-西南方向为建设用地产出效率的主要方向,且标准差椭圆的主轴与辅轴标准差都有所增加,说明在建设用地产出效率的主要方向与次要方向上都发生了分散现象。  相似文献   

17.
THEORIGINANDCHARACTERISTICSOFTHEGLACIALDEBRISFLOWINTHEDUKUHIGHWAYOFTIANSHANMOUNTAINS,CHINA¥XiongHeigang(DepartmentofGeography...  相似文献   

18.
Xichou County of Wenshan Zhuang and Miao Autonomous Prefecture in southeast Yunnan is one of the karst mountainous areas in southwest China showing typical rock desertification. During this study, we set up three soil erosion contrast test spots at Muzhe Village, Benggu Township, Xichou County, which was the birthplace of the Xichou rock-desertified land consolidation mode. The three spots included the terrace land spot (already consolidated land), sloping land spot (unconsolidated sloping land under rock desertification), and standard runoff spot (bare land spot). In 2007, a whole-year complete observation was conducted during the rainy season and "rainfall-erosion" data were obtained for 32 times. Our analysis showed that during the entire observation period, the number of the rainfalls that led to soil erosion accounted for 34.04% of the number of all rainfalls and the amount of the rainfalls that led to soil erosion accounted for 84.17% of the total amount of all rainfalls. The average erosive rainfall standard in the three test spots was 11.0 mm, slightly higher than the 10 mm standard that has been adopted all over China, but lower than the 12.7 mm standard of the US and the 13.0 mm standard of Japan. According to single-factor analysis, the soil loss in the sloping land spot (L2) and that in the bare land spot (L3) are correlated to certain extent to many other factors, including the single precipitation (P), rainfall intensity during the maximum ten minutes (I10), rainfall intensity during the maximum 20 minutes (I20), rainfall intensity during the maximum 30 minutes (I30), rainfall intensity during the maximum 40 minutes (I40), and rainfall intensity during the maximum 60 minutes (I60). Among these factors, they are of the highest relativity with I60. According to double-factor analysis, both L2 and L3 are of good relativity with P and I60. According to multi-factor analysis, L2 and L3 are also of good relativity with seven rainfall indexes, namely, P, Ia (average rainfall intensity), I10, I20, I30, I40, and I60, with their related coefficient R reaching 0.906 and 0.914, respectively. The annual soil losses in the three test spots are widely different: 1030.70 t/km2·a in the terrace land spot, which indicates a low-level erosion; 12913.22 t/km2·a in the sloping land spot (unconsolidated spot), some 12.5 times than that in the terrace land spot, which indicates an ultra-high-level erosion; and 19511.67 t/km2·a in the bare land spot, some 18.9 times than that in terrace land spot, indicating an acute erosion. These figures fully show that the Xichou rock-desertified land consolidation mode plays a significant role in soil conservation.  相似文献   

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