Geoscience

Tectonic Evolution of Central and South Tianshan Orogenic Belts in the Central Asia and Mineralization Background

ZUO Guo-Chao, LIU Yi-Ke, ZHANG ZHao-Chong, HUANG He

2011, 25(1): 1-14.

Asbtract ( 3247 )

PDF (6672KB) ( 2212 )

References | Related Articles | Metrics

The Central and South Tianshan orogenic belts are located across the Central Asia. The Late Proterozoic breakup event of Rodinia Supercontinent led to the formation of many variable-size blocks surrounded by palaeo-oceans. The NE-striking Talas-Fergana throughout the researched area was a characteristic of transform fault in Palaeozoic time, and it controlled the tectonic evolution and mineralization difference between east and west sections of the fault. In the north margin of the Central Tianshan microplate, there was a CambrianOrdovician paleoocean basin. The west section of its south margin had experienced two breakup events from Cambrian to Middle Devonian and formed an archipelago ocean setting. The carbonaceousand siliceous-shale formations in the passive margin of Silurian oceanic province are the best layers for hosting gold deposits. The paleo-ocean in the east section of the south margin of the Central Tianshan microplate occurred from Sinian to Late Devonian. During Late Carboniferous time, there were northwest thrust orogenic events in the west, whereas there were the reverse thrust orogenic events in the east sections. Continental collision-type granites are widespread through the South Tianshan area in the Late Carboniferous, which are genetically related to tungsten, tin, niobium-tantalum, molybdenum, copper, lead and zinc deposits. Talas-Fergana fault, which formed in Late Permian and Triassic, was characterized by dextral strike slip. Subsequently, the emplacement of the post-collision-type granites plays a key role in the mercuric and antimony mineralization. Talas-Fergana fault was characterized by strike slip and extension during Jurassic. In Cenozoic, the tectonic uplift resulted in compression and shortening of the South Tianshan was triggered by the northward subduction of the Indian Plate.

Characteristics of Overthrust in the Eastern Pamir Structural Arc, Western Tibetan Plateau

SONG Yang, HU Jian-Zhong, WANG Rui-Jiang, LI Rui-Qing, TIAN Bin, LI Shi-Jie

2011, 25(1): 15-21.

Asbtract ( 1944 )

PDF (4000KB) ( 1350 )

References | Related Articles | Metrics

Pamir structural arc is one of the most intensively deformed areas produced by continued compressing of Tibetan Plateau after collision between Indian and Eurasian plates. Geological investigation and interpretation for the seismic section in the eastern Pamir structural arc revealed that thrust nappe was composed of 4 zones from southwest to northeast, i.e, root zone, middle zone, frontal zone and frontal out zone, which are characterized by imbricate thrusting, thrust fold, fault related fold and monoclinal structure, respectively. The study of growth strata of Sugaite and Aketao growth anticlines occured in the frontal zone indicated that the Pamir structural arc was characterized by piggyback imbricated duplex. The deformation time was constrained at Pliocene to Early Pleistocene by growth strata and unconformity. The kinematical mode of thrust nappe was different between eastern and western sections. The thrusting in the west is vertical to extrusion direction, and in the east is oblique and clockwise strickslipe. The stratum shortening in the west was much bigger than that in the east.

Deformational Process from Thick-skinned to Thin-skinned Thrust in Xuefeng Mountain, South China: Evidence from SangzhiAnhua Tectonic Section

TANG Shuang-Li, YAN Dan-Ping, HONG Chang-Liang, ZHANG Wei-Chen

2011, 25(1): 22-30.

Asbtract ( 2549 )

PDF (8338KB) ( 1256 )

References | Related Articles | Metrics

Thick-skinned thrust separating from thin-skinned thrust by the Dayong fault in Xuefeng Mountain and area on its northwest, brings variable interpretations of Mesozoic tectonicprocess in South China, and thus the structural style and origin of the Dayong fault are the keys to well understand tectonics of Xuefeng Mountain. Field investigation, interpretation of the data of seismic section and magnetotelluric sounding along Sangzhi-Anhua tectonic section are applied in this paper.The results indicate that the thick-skinned thrust was produced by thrusting the Banxi Group over the Lower Paleozoic in Early Silurian to Middle Devonian. The re-activation of the thick-skinned thrust during Middle Triassic to Jurassic turned Dayong fault into a detachment fault along weak layer of Banxi Group with tiny dip angle towards southeast, which overprinted the old thick-skinned thrust in the meantime. This late deformation also resulted in a NW-ward overthrusting, fault-related chevron syncline and flat-ramp thrust fault, known as the thin-skinned thrust. Therefore, we conclude that the original thick-skinned thrust developed in Paleozoic era was overprinted, with a detachment fault in Xuefeng Mountain, by the NW-ward thrust in Mesozoic era which also produced the thin-skinned thrust on its northwest side.

Structural Evolution of Northern Jiangnan Uplift: Evidence from ESR Dating

SHU Qing-Bo, YANG Kun-Guang, CHENG Wan-Qiang

2011, 25(1): 31-38.

Asbtract ( 2837 )

PDF (7778KB) ( 1591 )

References | Related Articles | Metrics

Thirty-five samples from tectogenetic α quartz veins in northern Jiangnan uplift have been studied by using ESR dating method. The results show that the ESR ages of α quartz veins from northern Jiangnan uplift change between 195.8 Ma and 3.4 Ma, mainly from 75 Ma to 3.4 Ma (Himalayan). Combined ESR dating results with other geological evidence, the evolution history of northern Jiangnan uplift in the Cenozoic can be classified into two phases. The former is extend and faulted depressions stage (75-61.5 Ma).Normal faults and fault basins formed during this time. The latter is squeezing uplift stage (43.2-3.4 Ma). Its main feature is gravitational detachment structure. The Indosinian and Yanshanian structures had been intensely reconstructed during Himalayan. Entire eastern China experienced distinct tectonic movement, including southern North China, mid-lower Yangtze and northern Jiangnan uplift. The ESR dating results are consistent with geological evidence,which checked up the dependability of ESR dating.

Structural and Stratigraphic Analysis of the Runiange Formation in Luhuo-Daofu Area, Sichuan Province

XU Gang, JIANG Yuan-Sheng, XU Tian-De, WEI Yong-Feng, WEN Jian-Hua, SUN Bao-Wei

2011, 25(1): 39-47.

Asbtract ( 1975 )

PDF (8832KB) ( 1375 )

References | Related Articles | Metrics

The “Four-dimensional Cracking and Putting together Restoration Law of Tectonic Rock Sheet” is an important method in the orogenic zone geological mapping in recent years. Using this method, this article discussed disputing problems on Runiange Formation in Luhuo-Daofu area, Sichuan Province. From the view of the physical state, tense, phase, position and distortion, and the deterioration,the investigation indicated that the Runiange Formation structure is superposed longitudinally, being ordered generally and disordered partially. Laterally,various lothological layers do not extend stably, and constitute a large-scale structure lens network system. The geologic phenomena demonstrated that the Runiange Formation experienced the early deposition promiscuous action and the later structure promiscuous action; thus, the present typical orogenic zone non-Smith stratum body formed. This research not only enhances the Runiange Formation recognition degree, but also explains the primitive definition of the Runiange Formation.

Sedimentary Characteristics of Silurian Kepingtage Formation Bituminous Sandstone at Sishichang Section, Western Tarim Basin

WUN Li-Qun, JIAO Yang-Quan, RONG Hui

2011, 25(1): 48-54.

Asbtract ( 2270 )

PDF (5160KB) ( 1029 )

References | Related Articles | Metrics

Typical bituminous sandstone developed in the upper part of Silurian Kepingtage Formation at Sishichang section in western Tarim Basin, which are located in the middle-lower part of several normal graded sedimentary cycles. Based on the field outcrop section realism, identification under microscope, grain size ana-lysis and X-ray diffraction analysis, detailed study was done on the bituminous sandstone of this section. It was found that bituminous sandstone developed in sand flat and mixed flat,which were in the lower part of intertidal zone in tidal flat depositional system. In bituminous sandstone, fine sandstone and siltstone were most, with typi cal bidirectional cross bedding and shallow biogenic trace developed. The sediment was transported as saltation form and reformed by tidal action greatly. Most mineral composition was quartz and bioclast, with little clay mineral and feldspar. On this basis, reservoir quality of bituminous sandstone was analysed combined with physical property measurement. It was showed that the quality of feldspar-quartz sandstone with medium compositional maturity was the best, of which the feldspar content was 5% to 10% and the quartz content was 75% to 83%. The quality of quartz sandstone with higher compositional maturity was the next, of which the feldspar content was about 2% and the quartz content was more than 90%. The quality of sandstone containing lots bioclast was the worst, of which the bioclast content was about 60% and the quartz content was about 35%. This study has some reference meaning to the reservoir evaluation of Silurian bituminous sandstone.

Accommodation Zones and Their Controls on Depositional System in the Middle of Third Member of Shahejie Formation, South of Dongpu Sag

LIANG Fu-Kang, XU Xin-He, MU Xiao-Shui, LI Sheng-Li, XU Shu-Tang, LIU Wei

2011, 25(1): 55-61.

Asbtract ( 7403 )

PDF (4050KB) ( 2732 )

References | Related Articles | Metrics

Dongpu sag is a Cenozoic extend-faulted basin formed by extension contributed by Lanliao fault. Accommodation zones are main types of transfer zones developed in south of Dongpu sag. Based on fault-s configuration and displacement, four tendency types and three overlap types are summarized; moreover, eleven types of accommodation zones are confirmed, among which eight are found in south of Dongpu sag. Accommodation zones control the development of depositional systems in south of Dongpu sag: Synthetic accommodation zones formed in west slope can act as a sediment exit of large delta system; Fault-nose in degressive block of Lanliao fault can also play as an exit of relatively small fan delta system; Antithetic accommodation zones in central uplift zone, however, separate secondary catchment basins. The forming dynamics mechanism of accommodation zones is closely correlative with geometry and kinematics of Lanliao fault, whose cross section shape, displacement variation and strike-slip are the domain controlling factors.

The Response of Petroleum Trap Types to the Structural-Depositional Pattern in Shenxian Depression, Jizhong Sub-Basin

ZHANG Rui-Feng, LI Xian-Ping, XU Xin-He, TIAN Jian-Zhang, SUN Xiang-Can

2011, 25(1): 62-69.

Asbtract ( 2367 )

PDF (2113KB) ( 1156 )

References | Related Articles | Metrics

Shenxian depression is located in the center part of Jizhong Subbasin, North China, with extremely complicated structures and diverse sedimentation systems. There are many different recognizations of the classification of hydrocarbon traps (particularly stratigraphic trap) and their distribution in the past years, which has restriced the accurate hydrocarbon exploration in such kind of complicated faulted depressions. Five structure zones can be defined in Shenxian depression and each has its particular sedimentary pattern that results in different trap types. Four major types and 8 subdivided trap types of petroleum trap, such as structural trap, lithologic trap, stratigraphic trap and buried hill trap etc., were summarized in this paper, which had responses to the structuralsedimentary patterns in this area. Structural trap mainly composed of fault block and fault nose had a wider distribution scale and concentrated in bulges of the secondary structural zones, mainly in Shennan anticline and Yuke anticline. Buried hill trap mainly occured in Hezhuang-Shenxi buried hill zone and Shenze-Liucun low bulge of the northern gentle slope belt. Lithologic and stratigraphic traps mainly existed in two flanks of buried hill zone and Shennan anticline and Baisongzhuang trough in the south, which responded to lenticular sandy conglomerate, updip sand body and tectonic setting in these areas. Therefore, it can be concluded that structural-stratigraphic composite petroleum reservoirs should be more important in the future hydrocarbon exploration in Shenxian depression.

Reservoir Microscopic Characteristics and Displacement Efficiency of E₁f₃Reservoir in Shanian Oilfield, Subei Basin

ZHANG Chuang, SUN Wei, JIE Wei

2011, 25(1): 70-77.

Asbtract ( 4967 )

PDF (3787KB) ( 1393 )

References | Related Articles | Metrics

On the basis of microscopic characteristics research of E₁f₃ reservoir in Shanian oilfield, oil displacement efficiency has been measured by the authentic sandstone micro-model experiment. Influences of physical properties and pore structure on oil displacement efficiency have been studied, and the special phenomenon of samples which have similar permeability but great different oil displacement efficiencies has been explained. Furthermore, the accuracy of mercury-withdrawal efficiency which is used as oil displacement efficiency has been analysised. The result shows that the rock of the reservoir is fine pore-throat and strong anisotropy, which mainly is due to the fine grain-size, poor sorting, high-content interstitial matter and high compaction. Oil displacement efficiency increases as the physical properties become better and the throats become larger, but it has a complex relationship with throatsorting: large throat intensifies the heterogeneity between throats while it provides good connective channels among pores, and small throat ensures the uniform propulsion of the injection water. Oil displacement efficiency is mainly controlled by physical properties and the max connective throat, and it has a good correlation with mercury-withdrawal efficiency while they are different in the low-value zone.

Elang Sandstone Diagenesis in Sahul Block of Bonaparte Basin, Australia

LEI Jing-Mei, CHEN Jing-Yang, JIANG Pei-Hai, TAN Zhuo

2011, 25(1): 78-84.

Asbtract ( 2739 )

PDF (4528KB) ( 1622 )

References | Related Articles | Metrics

Elang sandstone formation (deltaic to shallow marine) is the significant reservoir in the Sahul block of Bonaparte Basin. The drilling data results indicate that the reservoir property has high quality in the north and poor one in the south. This thesis studies the diagenesis of Elang sandstone by impregnated thin-section, scanning electron microscopy, X-ray diffraction and so on, and points out that the diagenesis between the north and the south in the Sahul block is quite different. The diagenesis in the north is in the middle stage of A1 and includes cementation and dissolution, whereas in the south it is from the middle stage of A2 to the middle stage of B and consists of mechanic compaction, cementation and metasomatism. The difference of diagenesis is the key factor affecting the porosity of Elang sandstone reservoir as well as resulting in the difference of reservoir quality between the north and the south. Therefore, it is highly practical and important for reservoir appraisal in studying such differences among various areas and predicting favorable reservoir.

Oil Sources Analysis of the Jurassic Crude Oil in the Southern Tianhuan Depression, Ordos Basin

ZH AO Yan-De, LIU Xian-Yang, ZHANG Xue-Feng, ZHANG Zhong-Yi, LI Cheng-Shan

2011, 25(1): 85-93.

Asbtract ( 5819 )

PDF (3293KB) ( 1148 )

References | Related Articles | Metrics

The southern Tianhuan Depression is located in the southwest of the Ordos Basin, stretching across both of the west thrust belt and the Tianhuan Depression with complex geological conditions. In recent years, the exploration of the Jurassic low-amplitude structural-lithologic reservoirs has gained a great breakthrough with several high productive oilflow wells found in this region. However, there are some different points of view about the resources of the Jurassic oil and gas, which has constrained the further exploration. In this paper, comparative studies have been done about the Jurassic crude oil and three series of source rocks which are separately from the Chang 4+5, Chang 6 and Chang 7 Sections of the Triassic Yanchang Formation from the aspects of biomarker and carbon isotope, etc. with the methods of GC-MS and carbon isotope analysis. Besides, the oil sources of the Jurassic crude oil have been discussed according to the Jurassic oil and gas accumulation characteristics. The study results show that the Jurassic crude oil and source rocks in the sixth and seventh members of Yanchang Formation in the southern Tianhuan Depression have similar characteristics in the aspects of resource properties, sedimentary environments and maturity; meanwhile, the regional unconformities and cracks formed the migration pathway of the Jurassic reservoir beds and the crude oil of the sixth and seventh members of the Yanchang Formation; the Jurassic crude oil is mainly derived from the source rocks of the sixth and seventh members of the Yanchang Formation.

Research on Molybdenum Polymetallic Metallogenic Prognosis in Duguan-Yunyang District, Southwest Henan Province

XIAO Qiao-Yan, WANG Gong-Wen, ZHANG Shou-Ting, YAN Chang-Hai, SONG Yao-Wu, LI Lian-Shan,

2011, 25(1): 94-100.

Asbtract ( 10579 )

PDF (3642KB) ( 1079 )

References | Related Articles | Metrics

Taking DuguanYunyang district as a case study area, according to the multidisciplinary data, using nonlinear mathematical method, the geological prospecting information of multivariate, multi-scale, multi-dimension and multi-type is extracted. AHP method is selected to integrate prospecting information. On this basis, using two different combinatorial methods of “Kriging+Natural Breaks” and C-A fractal method, molybdenum polymetallic mineralization favorable targets are calculated and delineated. The results show that the main targets of the study area delineated by these two methods are same, but C-A fractal method can identify local mineralization favorable targets and can more deeply divide the targets. Combined with degree of regional exploration and mineral geological data, the targets delineated by C-A fractal method are further divided into three grades, ie, grade Ⅰ, Ⅱ and Ⅲ. The result shows that most known deposits are located in gradeⅠ,Ⅱ further prospecting areas，and Ⅲ area is a favorable prospecting area. Furthermore, the result offers a basis for further exploration.

Fractal Characteristics of Fault System and Ore-prospecting Prediction of Taxkorgan-Shache Area of Xinjiang

GAO Yong-Zhang, ZHANG Shou-Ting, SUN She-Liang, GU Wen-Shuai, MA Yong-Fei, BAI Yun

2011, 25(1): 101-107.

Asbtract ( 2634 )

PDF (3207KB) ( 918 )

References | Related Articles | Metrics

The fault system is an important ore-channeling and ore-hosting structure,which plays an important role in controlling the migration and accumulation of oreforming fluid.The fractal dimension value of the fault system is a comprehensive embodiment of the fault amount,scale,assembly pattern and dynamic mechanism. It can be a quantitative parameter to describe the complexity of the fault system.The distribution of ore deposit （occurrences） is controlled by fracture in TaxkorganShache area of Xinjiang, and the fractal geometry study of the Ⅰ，Ⅱ-1，Ⅱ-2 and Ⅲ metallogenic districts indicated that these fracture systems possess the well statistical selfsimilar character,and the fractal dimension value were as follows: 1.49，1.33，1.34 and 1.22. The quantitative ordination of the metallogenic potential in this area isⅠ＞Ⅱ＞Ⅲ，and the target ores of the meta llogenic districts are leadzinc-copper deposit,leadzinc polymetallic deposit and magnetite.This study points out the orientation of prospecting in Taxkorgan-Shache of Xinjiang Uygur Autonomous Region

Lead-zinc Exploration Prospect in the Zhanzanmubu Area, Xaitongmoin, Tibet

XIA Xiang-Biao, ZHENG Lai-Lin, LI Jun-Min, LI Zai-Hui

2011, 25(1): 108-113.

Asbtract ( 2424 )

PDF (4621KB) ( 1278 )

References | Related Articles | Metrics

The preliminary study of the lead-zinc exploration prospect in the Zhanzanmubu area, Xaitongmoin, Tibet is based on regional geology, surveys of stream sediments, and soil and high-precision magnetic measurements. The exposed stratum is mainly crystal tuff and andesite porphyrite of Tertiary Eocene Nianbo Formation. Exposed magmatic rocks are mainly Tertiary Eocene monzonitic granite and small area of granite-porphyry. Diagrams showing the elemental anomalies based on the stream sediment survey in the Zhanzanmubu area have disclosed that there are remarkable element anomalies of various scales, such as Pb, Zn, Ag, Au, Sb, Cu, Ba, Hg, Sn and As, especially those of Pb and Zn are relatively large. The soil profile in the Zhanzanmubu area shows that anomalies of Pb, Zn and Ag are more significant. The magnetic survey indicates that the anomalies of geochemical survey are nearby the magnetic anomalies.By qualitative analysis of magnetic anomalies, it is inferred that there are favorable for deep exploration prediction of these metal deposits.Magnetic anomalies indicate that it is favorable location for hydrothermal mineralization. By the combination relationship between elements from soil survey data,it is inferred that Pb，Zn and Ag，As，Sb，Cu are of the close. Combined with geochemical anomalies and geological characteristics, the leadzinc deposits in the Zhanzanmubu area may be of volcanic rock type associated with lead-zinc polymetallic ore deposits. It follows that the study area is expected to be a prospective area for the lead-zinc （silver） polymetallic ore deposits related with volcanic rocks in the Zhanzanmubu area.

Analysis on the Impact of Seismogenic Fault on the Micro and Macro-epicenter Deviation: Taking Xinjiang Area as an Example

LAN Xiao-Wen, TIAN Jia-Yong, XIE Zhou-Min, JIANG Wen-Liang, LU Ming, SHI Zhen-Liang

2011, 25(1): 114-121.

Asbtract ( 2653 )

PDF (2402KB) ( 871 )

References | Related Articles | Metrics

How to estimate the micro and macro-epicenter deviation is a key problem to earthquake emergency and rescue response. Taking Xinjiang area as an example, this study investigated the relationship between micro and macro-epicenter deviation and seismogenics structures, and provided a new method for the fast determination of possible macro-epicenter based on the micro-epicenter and seismogenics structures for the earthquakes Ms≥6.5. There are 3 types of faults in Xinjiang, including the thrust fault, the thrust-slip fault and the strike-slip fault. The deviation of the ideal micro-epicenter direction depends on the nature of rupture (such as unilateral rupture, bilateral rupture), so it is difficult to determine the exact location of the ideal micro-epicenter in the seismogenic fault, and it is a certain randomness, but the deviation of the micro and macro-epicenter is consistent with the overall direction of tectonic stress direction. The macro-epicenter location is located in or near the seismogenic fault in actual application.

Faults in Crystalline Basement of Shiwu Faulted Depression in Songliao Basin Determined by High Precision Gravity and Geomagnetic Data

YAN Yu-Mei, LIU Shao-Feng, Pan Feng, WU Jian, QI Pan-Wen

2011, 25(1): 122-128.

Asbtract ( 4313 )

PDF (9922KB) ( 1540 )

References | Related Articles | Metrics

Based on 1∶50,000 size gravity and magnetic data of Shiwu faulted depression in Songliao Basin，twenty-one major faults in Shiwu faulted depression were determined by methods of frequency domain transformation in gravity and magnetic field，discrete 2D wavelet transformation，correlation filtration and anomalies stripping. The faults in basement of Shiwu faulted depression were determined，and could be divided into the following four groups, Shangshutai big fault zone(F1)，Bawu fracture zone(F2)，Jinshan fault zone(F3) and Dayushu fault zone(F4). Shangshutai fault in western border of Shiwu faulted depression and a series of faults in NE direction inside the depression consist of the structure of basement faults in Shiwu depression.On the whole，Shangshutai fault develops as a segment of a circle in planar configuration，and its direction is NE in its north，SN in the middle，and SW in the south. Three fault groups of F2，F3 and F4 are determined as normal fault in NE direction in Shiwu faulted depression，moreover，the trend of these normal faults are coincide with the northern segment of fault F1，hence，these four fault groups would become into being in a same tectonic stress field, and the four main faults compose of the basement of Shiwu faulted depression. The results provide a significant evidence for prospecting hydrocarbon of the basement.

Bidirectional Linear Regression Method for Calculating Critical Point, Framework and Pore Fluid Parameters of Water-saturated Dolomite

LIU Si-Si, NIU Bin-Hua, SUN Chun-Yan, YANG Kui

2011, 25(1): 129-136.

Asbtract ( 2428 )

PDF (1126KB) ( 1375 )

References | Related Articles | Metrics

The critical porosity and relative elastic parameters of the porous media are usually studied by methods of experimental measurements and data analysis, however it is difficult and complicated to calculate elastic parameters by these methods. So in this paper, a numerical calculation approach and some equations of bidirectional linear regression are provided for calculating these elastic parameters. The derived bidirectional linear equations in this paper show that ρ,ρV2S sand ρV2P are functions of, at the same time is a function of ρ,ρV2S and ρV2P. Based on these equations, in accordance with density, compressional and shear velocities of entirety, twelve partial elastic parameters of framework, pore fluid and critical point can be obtained. Correlation coefficients of simulated data and measured data are over 90%, which proves the feasibility of the equations and the availability of this method. In the field of oil and gas exploration, the method can be directly used to calculate elastic parameters of pore fluid, and plays a crucial role in predicating oil and gas reservoirs.

Analysis on Causes of Perilous Rocks in Yungang Grottoes

FANG Yun, CHEN Xing, LIU Jun-Hong, CHEN Xun, YAN Shao-Jun

2011, 25(1): 137-141.

Asbtract ( 2037 )

PDF (1439KB) ( 1117 )

References | Related Articles | Metrics

Perilous rock is one of the main geological hazards in sandstone grottoes, especially in Yungang Grottoes. The study on causes for perilous rocks is useful for prevention and cure of perilous rocks in sandstone caves. In this paper, the various influence factors of perilous rocks were analyzed in detail by engineering geology method. Box-like synclines and fractures were macroscopic tectonic origins of perilous rocks. The near E-W tensile cracks and N-E shear fissures directly controlled the perilous rocks- evolution. The differences in height between cliffs directly controlled the development scale of the unloading zone of slopes, and determined the hazard energy of perilous rocks, and the differences in weathering of soft-hard alternate multilayers generated cliffs and cavity to form perilous rocks shape. Fissure waters and rainfalls directly affected the stability of perilous rocks. The stability of perilous rocks which had undergone longterm effects of freezing and thawing, temperature differences and alternate drying-watering continued to be deteriorated, and engineering activities are the main triggering cause of the perilous rocks- instability. The result provides an important basis for prevention and cure of perilous rock masses, and is valuable to analyze the stability of Yungang Grottoes.

Study on Slope Response under Seismic Loading:Taking the Dongshan-Shiziliang Profile in Qingchuan, Sichuan as an Example

WANG Fu-Hai, WANG Yun-Sheng, SUN Gang, XU Hong-Biao, LUO Qi-Long

2011, 25(1): 142-150.

Asbtract ( 2743 )

PDF (5660KB) ( 1304 )

References | Related Articles | Metrics

Based on systematic analysis of field data of earthquake monitoring profile in Qingchuan, Sichuan，this paper employed the universal finite element analysis software (ANSYS) to establish a numerical model of Dongshan-Shiziliang monitoring profile, and the response of the slope under seismic loading was simulated. The results show that: under seismic loading, the seismic response of slope does not monotonously increase, but is closely related with the slope landform and the development degree of fractures in rock masses; the seismic response increases gradually from the inside of slope to its surface, and when the slope direction is same with the wave propagation the response is greater than that in the opposite direction. This study provides a basis for proposing a more reasonable method to evaluate slope stability under seismic loading.

Preparation of Light-weight Magnesium Oxide and Calcium Carbonate from Dolomite by Acidification：An Experimental Study

YAO Wen-Gui, MA Hong-Wen, JIANG Xiao-Qian, LIU Yu-Qin

2011, 25(1): 151-156.

Asbtract ( 2578 )

PDF (1349KB) ( 1576 )

References | Related Articles | Metrics

The dolomite powder, sampled from Huangyue valley, Lushi County of Henan Province, was dissolved using hydrochloric acid to obtain the solution of MgCl₂ and CaCl₂. The iron and aluminium cations in the solution were removed by adjusting its pH to 6-7. The lightweight magnesium oxide and calcium carbonate were prepared using the purified solution by ammonification, aging and carbonization. This study mainly investigates the effect of ammonification temperature(time) and the aging temperature(time) on the ratio of Mg²⁺ precipitation, and the effect of carbonization time on the crystal form of calcium carbonate. Scanning electron microscope (SEM) and chemical analysis methods were used to characterize the products. The lightweight magnesium oxide obtained is platelet in form with the average particle size of 150 nm, and matches the chemical industry standard HG/T2573—2006. The light-weight calcium carbonate obtained is sphere in form with the average particle size of 100 nm, and matches the chemical industry standard HG/T2567—1994. The presented technique which is characterized by low energy consumption and high utilization ratio, is a potential environmental friendly way for the clean processing of dolomite ores.

Pre-desilication of Sodium Aluminate Solution from Aegirine-augite Syenite：An Experimental Study

WANG Xia, MA Hong-Wen, YU Zi-Jian, WANG Xiao-Yan, Zhou Dan

2011, 25(1): 157-162.

Asbtract ( 2044 )

PDF (1682KB) ( 1323 )

References | Related Articles | Metrics

The principal phase of potassium-distilled filter residue of aegirine-augite syenite is sodium aluminum silicate hydrate rich in Al2O3 and SiO2. The high caustic ratio sodium aluminate solution was obtained from filter residue treated by high pressure hydrochemical process. The desilication reaction was experimentally studied by adding different types of desilication agents. The orthogonal experimental results show that in the process of the desilication from sodium aluminate solution, the descending order of affecting factors is as follows：desilication agent type, desilication time, desilication temperature. The optimal conditions of desilication are that the desilication agent is tricalcium hydroaluminate, and desilication temperature is 160 ℃ and the desilication time is 3.5 h. The silicon index of the refined aluminate solutions was obtained to be above 1,800 by one-step desilication procedure. According to X-ray diffraction analysis, the major phase of derived products is hydrogarnet. The diffraction intensity of hydrogarnet increases sharply with the desilication time increasing. The results of scanning electron microscopy and EDS analysis show that hydrogarnets reveal high crystallinity and perfect fine-grains, and SiO2 impurities easily attached with the small crystals, so a better effect of silicon removal is achieved.

An Experimental Study on Preparation of Nanocrystalline Wollastonite Powders from Sodium-Calcium Siliceous Hydration Residue

WANG Xiao-Yan, MA Hong-Wen, YU Zi-Jian, WANG Xia

2011, 25(1): 163-168.

Asbtract ( 3750 )

PDF (1439KB) ( 1246 )

References | Related Articles | Metrics

This study is focused on the efficient utilization technique of sodium-calcium siliceous hydration residue, which is remained after treating the high silicon aluminum-containing materials aegirineaugite syenite. The alkali of sodium-calcium siliceous hydration was recycled by its self- hydrolysis and decomposition in NaOH solution. The obtained diluted NaOH solution can be recycled after being concentrated. The influences of temperature, L/S ratio, initial Na2O concentration and washing times were experimentally investigated. The alkali recovery proportion is up to 90% at the conditions of 180 ℃, L/S ratio 4∶1, initial Na2O concentration 20 gram per litre and washing six to seven times. According to the differential thermal analysis and thermogravimetry of the solid residue remained after alkali recovery, the calcination temperature of preparing wollastonite is 820 ℃. Nano-crystalline wollastonite-2M was prepared, with particle size range from 50 to 100 nm, and its reaction mechanism was discussed.

Assessment of the Heavy Metal Pollution and the Potential Ecological Hazard in Urban Soil of Shijiazhuang City

CUI Xing-Tao, LUAN Wen-Lou, GUO Hai-Quan, LI Sui-Min, SONG Ze-Feng

2011, 25(1): 169-175.

Asbtract ( 3008 )

PDF (2555KB) ( 991 )

References | Related Articles | Metrics

With the urban soil of Shijiazhuang city as a target, this essay evaluates the environmental quality of soil heavy metals and pollution characteristics by adopting the single factor index method and Nemerow comprehensive index method. Besides, the potential ecological hazard index suggested by Hakanson is used to assess the ecological hazard of heavy metal in urban soil. The results show that the elements, according to the pollution degree of heavy metal, are followed by the order of Cd>Zn>Hg>Cr>Ni>Pb>Cu>As. Most importantly, Cu, Pb, As and most of Ni are in a clean and safe condition, only to find 0.45% of Ni in an alert state. However, Cd, Hg, Zn, Cr are all in the pollution state, especially the pollution of Cd represents the largest polluted area, reaching 1.36%. On the whole, Integrated Pollution Assessment showed the soil environment is good, in which clean, safe, alert, contaminated soil area ratio is 65%, 31.82%, 2.73 %, 0.45% respectively; and alert and contaminated soil area accounts for 3.18%. Its formation may be related to industrial production and human activities. Heavy metal elements resulting in potential ecological hazard of heavy metals are mainly Hg and Cd, which have reached to strong potential ecological hazard level and moderate potential ecological hazard level, the remaining heavy metals are all mild potential ecological hazard. Considering synthetically the potential ecological hazard of heavy metals, we found that the percentage of small, medium, high and strong ecological hazard is respectively 38.6%, 53.2%, 7.3%, 0.9%. Therefore, the general performance is the medium potential ecological hazard.

Contrast of Land Quality Geochemistry Appraisal Result in Different Sampling Density：Taking Longyou County of Zhejiang Province as an Example

JIAN Zhong-Hua, WANG Shi-Ji, HUANG Chun-Lei, WEI Ying-Chun, QU Ying

2011, 25(1): 176-181.

Asbtract ( 5444 )

PDF (2482KB) ( 1176 )

References | Related Articles | Metrics

According to “Land Quality Geochemistry Appraisal Specification”,this article carries out the land quality geochemical assessment about soil samples in Longyou County, Zhejiang Province in three kinds of sampling densities, which are 1 piece/4 km2, 1 piece/km2 and 4 pieces/km2. Our works focus on the differences comparison and application areas of the results of land quality geochemical assessment. The results show that the density of 1 piece/4 km2 can serve for the land management in provincial level, and the density of 4 pieces/km2 can help for the protection and development of land in county city level,and also can instruct the land management and practice of land quality geochemical assessment in village and town level. This research provides a practical and theoretical foundation for the development of land quality geochemical assessment in future.

Health Risk Assessment of Drinking Water in Poyang Lake Region in Jiangxi Province

QIN Wen-Wen, YANG Zhong-Fang, HOU Qing-Xie, CAO Tie-Ning

2011, 25(1): 182-187.

Asbtract ( 3158 )

PDF (2139KB) ( 1270 )

References | Related Articles | Metrics

In this study, As, Cd, Hg, Pb, F, ammonia nitrogen, and phenol in drinking water of 24 counties and cities in Poyang Lake region were studied according to the USEPA health risk assessment model. The research results showed that the highest risk caused by As and Cd through drinking water were appeared in Pengze （29.1×10^-6·a^-1） and Poyang County （7.94×10^-7·a^-1） respectively, while both were lower than the maximum allowance levels recommended by ICPR （5×10^{- 5}·a^-1）. The highest risk of noncarcinogen caused by phenol was in Poyang County （4.99×10^-9·a^-1）, which was lower than the maximum allowance levels recommended by ICPR. Finally, the total health risks, calculated by adding the carcinogens risks to the non-carcinogenic ones, ranged from 10^-6·a^-1 to 10^-11 ·a^-1, which indicates a low risk without health hazards. However, the results revealed a high risk of drinking water in Pengze County, Nanchang city, Nanchang County, Hukou County, so more attention should be paid to the environment in these regions.

Table of Content