Environmental Conditions of Barchan Dune and Barchan Chain-A Case Study from the Hexi Desert Area of Gansu

[Objective] The paper was to discuss why the top of tall barchan dunes and barchan chains widespread in single prevailing wind area had not been leveled by wind erosion. [Method] Based on the preliminary survey of distribution status,the morphological characteristics and environmental conditions of barchan dunes and barchan chains in Hexi desert area of Gansu were investigated in details. The significance of difference between samples and significance of correlation between indicators were examined via variance test. [Result] Barchan dunes and barchan chains in Hexi desert area of Gansu distributed at the leeward direction of desert fringe,generally in patch distribution. The distribution area was gravelly beach or cohesive gravel beach,with broader dune slack; winds in distribution area of barchan dunes and barchan chains blew obviously from one direction,while winds at other directions were light or occasionally strong but with low frequency;the barchan dune in the desert fringe of Hexi desert area of Gansu was relatively tall,while barchan chain was even more taller and larger. Coincidence or separation of the dune peak and the sand ridge might be related to distribution frequency of dominant prevailing wind or wind at opposite direction and the observation seasons.[Conclusion]Studying top stability of barchan dune has an important academic value in revealing blowing sand movement rule at desert fringe,invasion of sand flow,and expansion of desert.

Estimation of Fracture Geometry Parameters and Characterization of Rock Mass Structure for the Beishan Area,China

The accurate estimation of fracture geometry parameters and the characterization of rock mass structure are two important topics in the geological disposal system of high-level radioactive waste(HLW).The Beishan area,as the current preselected area for China’s HLW disposal,has three subareas considered to be the key survey area at the stage of site selection.In this paper,a comprehensive survey method conducted on the outcrop is developed to estimate fracture geometry parameters.Results show that fracture occurrence obeys a Fisher distribution,fracture trace length obeys a normal distribution,and the distribution of spacing obeys a negative exponential distribution.An evaluation index,Rock Mass Structure Rating(RMSR),is proposed to characterize rock mass structure for the three subareas.The results show that the Xinchang area is more suitable to act as China’s HLW disposal repository site.At the same time,the index can also be applied to characterize surface rock mass structure and rock mass integrity at the site selection phase of HLW disposal.

Many New Dinosaur Fossil Spots Discovered in the Dunhuang-Yumenguan-Jiuquan Area of Gansu Province, China

Two Mesozoic intramontane basins are developed in the Dunhuang-Yumenguan-Jiuquan area of Gansu Province,China,i.e.,the Gongpoquan Basin（E97°30′-98°10′,N41°30′-41°45′）and the Yujingzi Basin（E98°15′-99°00′,N40°15＇-40°40＇）（Fig.1）.A large number of dinosaurs and other fossils have been discovered in these two basins,which are called dinosaur＇tribes＇by paleontologists.

Geochronology, Geochemistry and Tectonic Significance of Dike Swarms in Beishan, Gansu

Study area is located at Beishan,Gansu province.Beishan area located at conjunction site among Tarim plate,Sino-Korean plate and Kazakhstan plate,this special tectonic position has a very complex geological tectonic.

The first discovery of eclogite and Palaeoproterozoic granitoids in the Beishan area,northwestern Gansu Province,China

The eclogite, discovered in Liuyuan, occurs as lenticular enclave within granitic gneiss. It has typical features of eclogite in petrology and mineralogy. The eclogite provides an important wirdow to reconstruct the tectonic border of the Tarim block. The granitoids, located in Baihu area, yield U-Pb zircon ages of 1 660—2 000 Ma (Palaeoproterozoic), which irrplies an early Precambrian basement in the area.

RECENT TECTONIC DEFORMATION ANOMALY AND EARTHQUAKES IN GANSU-NINGXIA-QINGHAI AREA

By processing and analyzing geodetic data of vertical deformation, fault deformation and horizontal deformation by GPS in Gansu Ningxia Qinghai area and by comparing them with geological structures and many medium to strong earthquake activities in this area, some features of recent tectonic deformation anomaly and the development of medium to strong earthquakes are studied. The results show that: ①Near the main faults tectonic deformations are relatively large. The amount of vertical movement and the deformation status evolve with time. The horizontal movement and deformation show obvious compressional strike slip character. ②The dominant stress of tectonic deformation and seismic development in this area comes from the persistent northeastward compression of Qinghai Tibet block;The time spatial distribution evolution of tectonic deformation and seismic activities are closely related to dynamic evolution of block motion and regional tectonic stress field. ③The abnormal uplift and high gradient deformation belts and remarkable fault deformation anormaly on the borders of regional tectonic blocks are indicators of developing moderate to strong earthquakes but earthquakes may not necessarily take place in the position of maxium deformation, it usually occurred in the region where fault deformation anormaly shows “trend accumulation acceleration turn ” variation character or nearby. On the basis of above study, a preliminary prediction for strong earthquake risk in this area is given.

Geochronology,Geochemistry,and Sr-Nd-Hf Isotopes of the Diorite Porphyrites from the Weining Beishan Area,Ningxia Hui Autonomous Region:Constraints on Their Source and Tectonic Implications

The Weining Beishan area of Ningxia Hui Autonomous Region is located at on the western edge of the Helanshan tectonic belt,which is a tectonic joint among Alxa Block,Ordos Block,and North Qilian orogenic belt.However,the tectonic evolution of this area remains unclear due to the lack of magmatic information.This paper conducted researches on geochronology,geochemistry,and Sr-Nd-Hf isotopes of the diorite porphyrites exposed in the Weining Beishan area.The zircon U-Pb dating yields two ages of 145.0±1.1 and 146.2±1.5 Ma,and the whole-rock geochemical data indicate that the diorite porphyrites are metaluminous to weakly peraluminous and high-K calc-alkaline series.The characteristics of highly initial^(87)Sr/^(86)Sr ratios(0.70816 to 0.71047),negativeε_(Nd)(t)(−8.9 to−8.4),and negativeε_(Hf)(t)(−13.8 to−21.2)indicate that the diorite porphyrites originated from partial melting of the middle-lower ancient crust related to the North China Craton.Combined with the regional geology,we suggested that partial melting was triggered by a tectonic activity of deep faults cutting through the crust under the regional stress transformation from compressing to extension during the Late Jurassic–Early Cretaceous,which is probably related to the westward subduction of the Paleo-Pacific Plate.

Numerical modeling of the regional ground water flow in Beishan area, Gansu Province

The characterization of the regional ground water flow system is very important to high-level radioactive waste geological disposal. The Beishan area, located in northwestern Gansu Province, China, is selected as a potential site for disposal repository. The area includes about 100000 km2 and has complicated hydrogeological conditions, which greatly increase the computational effort of regional ground water flow models. In order to reduce computing time, parallel computing scheme was applied to regional ground water flow simulation. Models with over one million cells were used to simulate how the faults and different recharge conditions impact regional ground water flow, both in steady and transient state. The results of this study provide regional ground water flow information for site characterization of the potential high-level radioactive waste disposal.

Emergy-based study on eco-economic system of arid and semi-arid region:a case of Gansu province,China

Taking Gansu province as a model case,this study provides an integrated analysis on the eco-economic system of arid and semi-arid region based on emergy synthesis theory. Through calculating the values of renewable emergy flow,non-renewable resources,imported emergy,exported emergy,waste emergy,and total emergy during the period of 1978-2007,the performance of Gansu eco-economic system was analyzed. The results indicated that the renewable emergy flow within the province basically remained steady state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy and exported emergy were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively in 2007. The nonrenewable emergy flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej,with annual growth rate of 8.7%,while the estimated total emergy was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007,with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty years was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity of sustainable development. The environmental loading ratio was 0.53 in 1978,increased to 6.06 in 2007,indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978,increased to 7.06 times in 2007. During the period of 1978-2007,the emergy rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analysis revealed that the emergy density presented a trend of gradual increase,and then the emergy currency ratio in Gansu decreased from 7.08×1013 sej/Chinese Yuan to 7.82×1012 sej/Chinese Yuan.

Two Alternating Processes of Particle Size Distribution of Barchan Dunes at the Edge of the Oasis in Hexi Corridor, Gansu

Barchan dunes are a common type of dune. There are a lot of barchan dunes at accumulated sand-belts of the oasis edge of Hexi desert area of Gansu. What is characteristic of the particle size of barchan dunes? How is this particle size characteristic formed? Characteristics of particle size were analyzed in this paper by comprehensive investigation and sampling in Hexi Corridor desert area, and repeated sampling and determination in Minqin desert area. The results showed that:(1) The particle size of 0.25–0.05 mm and particle size of 0.5–0.25 mm were the main ingredients at the surface 0–5 cm depth of barchan dunes and barchan dune chains in desert area in Hexi Corridor of Gansu. Sand in Gulang desert area was relatively finer and the particle size was quite different from that of Jinchang, Linze, Jinta and Minqin desert area;(2) The particle size was changed from coarse to fine from the bottom to the top of the dunes in the main wind direction(NW) process. i.e. there was the most silt at the top of the dunes, followed by the middle of the leeward slope. The bottom of the windward slope had the most coarse sand, followed by the middle of the windward slope. The barchan dunes were changed from coarse to fine, then from fine to coarse from the bottom to the top of the dunes in the reverse wind direction(SE) process, i.e. there was the most silt in the middle of the windward slope, followed by the top of sand dunes. The bottom of the windward slope had the most coarse sand, followed by the middle of the windward slope. The standard deviation and coefficient of variation of sand dune particle size in the main wind direction process was larger, and the standard deviation and coefficient of variation of sand dune particle size in the reverse wind direction process was smaller;(3) The two processes of the main wind direction(NW) and the reverse wind direction(SE) led to alternating changes in particle size in various parts of the dunes. Two different conclusions on particle size distribution of barchan dunes in windward slope were due to the observation season differences.

Paleomagnetism of early Paleozoic volcanic rocks from the Beishan area,Gansu of northwest China:Preliminary insight into early Paleozoic kinemics of the Beishan terrane

We report rock magnetic and paleomagnetic results for Middle Silurian Gongpoquan and Middle Ordo-vician Huaniushan volcanic samples collected from the Ma-zongshan and Hongliuyuan areas of Gansu Province, northwest China. The results indicate that the main magnetic mineral of the Gongpoquan and Huaniushan volcanic rock is magnetite, and it may remain characteristic remanent magnetization acquired at the time of formation of the rocks. However, with the exception of samples from site go20, most of Middle Ordovician Huaniushan volcanic samples have a very weak nature remanent magnetization, and generally show an erratic demagnetization behavior, which does not allow isolation of characteristic remanent magnetizations from these samples. Comparison of paleomagnetic results obtained from the Beishan area of Gansu with Paleozoic apparent polar wander paths for Tarim and Siberia suggests that the Beishan tarrane, the southern part of the Beishan area of Gansu beyond the Mingshui-Shipanjin-Xiaohuang-shan zone,

A Study of the Thermal Conductivity Property of the High-level Radioactive Waste Repository:The Case of Beishan Preselected Site,Gansu Province

The research and development of high-level radioactive waste(HLW)repository is a long-term systematic engineering project.Normally,it involves such stages as foundation study,site selection and assessment,underground research laboratory testing, and the design,construction,operation,and close of the repository.The key issue in repository design

Metallogenetic epoch and mechanism of the tungsten ore in Yushan, Beishan orogenic belt, Gansu

Using SHRIMP zircon U-Pb dating methods and cathodoluminescence (CL) technique, we have pre- cisely dated ore samples from tungsten ore deposit, ore-bearing volcanic-sedimentary strata and granite in the Yushan region within the east Tianshan-Beishan W-bearing zone. This study reveals Yu- shan tungsten ore deposit zone formed in 250 ± 9 Ma, and it is closely associated with the Permian granites and felsic volcanic rocks. This new type of tungsten ore deposit in the east Tianshan-Beishang multiple-metallogenetic province may probably be associated with the regionally right-literal shearing after the main Carboniferous collisional orogeny, and the formation of pull-apart basin and the felsic magmatism.

A Study of Siliceous Pneumoconiosis in a Desert Area of Sunan County,Gansu Province,China

Three hundred and ninety five residents in a desert area were examined with chest radiographs and 28 cases with siliceous pneumoconiosis were found. The prevalence of siliceous pneumoconiosis was 7.09%, and that over 40 years of age was 21%. The histological findings of lungs from a camel living in that area for 20 years also confirmed to have siliceous pneumoconiosis.

甘肃北山南部早古生代古亚洲洋俯冲作用:来自明舒井埃达克质侵入体锆石U-Pb年龄及地球化学的证据

甘肃北山南部具有重要的构造位置与复杂的构造演化历史,制约着北山造山带大地构造归属研究。北山明舒井埃达克质侵入体位于南部辉铜山以西地区,岩性主要为二长花岗岩、正长花岗岩、花岗闪长岩、石英闪长岩等。对明舒井侵入体中的二长花岗岩、正长花岗岩和花岗闪长岩进行LA-ICP-MS锆石U-Pb测年,定年结果分别为423.4±3.4 Ma、425.4±2.3 Ma和437.8±3.5 Ma。岩石SiO2含量多数大于56%(55.53%~64.42%),Al2O3大于15%(15.1%~17.79%),MgO多数小于3%,全部小于6%(2.07%~3.5%),Y和Yb含量均较低,同时轻稀土元素富集,Eu异常不明显,Sr含量较高,具有与埃达克岩相似的特征。综合区域地质背景,认为北山南部志留纪埃达克质侵入岩形成于活动大陆边缘火山弧环境,可能是志留纪古亚洲洋向北消减俯冲背景下岩浆作用的产物,同时发生了大规模的地壳增生。明舒井埃达克质侵入岩体的识别为北山造山带早古生代构造演化提供了重要依据。

甘肃北山红石山地区扫子山组构造变形特征及其动力学背景

甘肃北山地区扫子山组形成于早石炭世,是红石山蛇绿构造混杂岩的重要组成部分,记录并保存了红石山古洋盆形成及演化的地质信息,是讨论红石山地区晚古生代古地理环境及洋盆构造属性的重要窗口。详细的野外地质调查发现,该套地层构造变形强烈,原始层理难以辨识,为研究该套地层的沉积环境增添了难度。基于此,在查明扫子山组物质组成的基础上,通过详细的构造解析,厘定其构造序列,并通过剥离后期构造改造,恢复原始沉积层理。结果表明,扫子山组经历了3期构造变形,第1期为北北西—南南东向逆冲兼左行走滑,可能为洋壳向北俯冲的产物;第2期为北北东—南南西向挤压兼右行走滑脆-韧性变形,可能为碰撞阶段的产物;第3期构造变形以北东—南西向左行走滑为主,为次一级的晚期构造变形。变形样式及变质程度表明,扫子山组以中浅层次构造变形为主,地层未发生明显的倒转和缺失,该套地层物质成分及空间分布具有明显的规律性,显示裂谷型盆地向南趋于成熟的火山-沉积特征。结合红石山-蓬勃山断裂以北发育石炭纪—二叠纪弧岩浆岩,揭示了红石山古洋盆向北俯冲的动力学过程,为进一步研究中亚造山带南缘构造演化过程提供地质依据。

甘肃北山地区晚三叠世煌斑岩地球化学特征及构造意义

甘肃北山地区位于中亚造山带南缘,是研究中亚造山带构造演化的关键区域。煌斑岩多为岩石圈地幔在伸展背景下低程度部分熔融形成的碱性岩石,确定其形成时代和岩石成因可为区域构造演化提供新的依据。笔者对北山地区柳园南煌斑岩进行了系统的岩石学、地球化学和锆石U-Pb年代学及Hf同位素研究。柳园南煌斑岩的锆石U-Pb年龄为(228.2±1.1)Ma(晚三叠世)。煌斑岩中富含金云母和角闪石等富挥发性组分的矿物。岩石地球化学分析表明:柳园南煌斑岩属于超钾质煌斑岩,母岩浆为碱性岩浆系列;全岩微量元素具有明显的Nb-Ta和Zr-Hf负异常,锆石εHf(t)值为0.5~4.9,平均值为+2.8,具俯冲洋壳板片流体交代特征。柳园南煌斑岩中橄榄石Mn/Fe与Ca/Fe值对比表明,柳园南煌斑岩源区为富金云母的方辉橄榄岩地幔;微量元素模拟计算表明,地幔源区具有富集的特征。因此,柳园煌斑岩岩浆源区为被俯冲板片流体交代的岩石圈地幔。结合前人对中亚造山带南缘构造演化的研究,北山南部地区在晚三叠世时已进入陆内伸展阶段,减压作用促使被俯冲流体交代的岩石圈地幔发生低程度部分熔融,形成柳园煌斑岩脉。

甘肃北山红柳园—辉铜山地区成矿地质条件、地球化学特征及找矿新发现

甘肃北山红柳园—辉铜山地区位于甘肃北山南带,是形成铜、镍、铁、铅锌、钼、金、银等矿床的有利地区,具有较好的找矿潜力。通过开展成矿地质条件分析,总结控矿关键因素,依据水系沉积物地球化学特征,确定Au、Ag、As、Sb、Hg、W、Sn、Ni、Cu为区内主要的成矿(伴生)元素。Ni、Cu异常与基性-超基性侵入岩的分布有关,Au异常受华力西中期似斑状花岗岩及加里东晚期石英闪长岩控制明显,与区域性断裂及其旁侧平行或“入”字斜交的次级断裂关系密切。异常查证新发现铭扬铜镍矿、杨帆金矿等多处矿点及矿化线索,结合区域地质、物探、化探特征,优选出4处具较大成矿潜力的找矿远景区,尤其是早古生代铭杨铜镍矿的发现,实现了北山地区近年来铜镍矿找矿新突破。研究成果可为下一步找矿勘查部署提供重要依据。

甘肃中部旱台田地10个饲用玉米品种生产性能及营养品质研究

试验为选出甘肃中部旱台田地适应性强的饲用玉米品种,2022年在甘肃中部旱台田地代表的榆中县引进了10个饲用玉米品种进行筛选试验。试验以主栽品种陇单4号为对照(CK),对引进的9个饲用玉米品种进行了比较试验,对饲用玉米农艺性状、草产量和营养物质进行了测定分析。结果显示,10个饲用玉米品种在甘中部旱台田地春播,均能够适期收获。2022年浩育2号和陇单4号(CK)全年折合鲜草产量较高,分别为40305.36和36638.33 kg/hm^(2),折合干草产量分别为13432.48和11652.11 kg/hm^(2)。10个饲用玉米供试品种中,先玉1483的酸性洗涤纤维含量最低,达到了国家一级青贮玉米标准,但产量过低。研究表明,浩育2号在甘中部旱台田地适应能力最强,产量最高,营养品质较好,达到国家二级青贮玉米标准,是具有推广潜力的饲用玉米品种。

甘肃涉藏地区锅庄舞风格特征研究

锅庄舞是集中体现藏民族美学思想的团栾舞蹈,由十三种舞步和九大类手势动作组合而成.颤、开、顺、左、绕、舞袖是锅庄舞的六大动作特征;走、跳是主要运动形式;圆或同心圆、弧线、直线是主要队形;舞曲多用地域风情特征明显的藏族民歌歌舞音乐,分为舒缓平和的慢板乐段和热烈奔放的快板乐段;舞蹈分为序舞、慢舞、快舞、结束四个舞段;服饰明艳华贵,主要是“藏式长袍+衬衣”;男子动作大而奔放、女子动作小而秀美.碌曲锅庄舞博采众长、久负盛名;玛曲草原锅庄舞粗犷豪放;夏河寺院锅庄舞庄严肃穆;迭部、舟曲林区锅庄舞小巧活泼;陇南、天祝山地锅庄舞稳重优美.