Search

The Xiaorequanzi copper–zinc deposit, located in the eastern Tianshan, is considered as a medium‐sized polymetallic deposit in Xinjiang, NW China. Understanding the structural framework and delineating the location of intrusions as well as the distribution of ore‐controlling strata in this mining area are vital for identifying new potential exploration areas. This paper aims to provide new information on the subsurface structures of the Xiaorequanzi copper–zinc deposit and to explore new target area for the ore prospecting based on comprehensive interpretation of multiple geophysical datasets. Several potential field filtering methods were used to study the spatial distribution of the geological structure. The structural lineament was delineated based on various source boundary detection results. Euler deconvolution method was used to estimate the field source depth, and the structure model was constructed from 2.5D forward gravity modelling, constrained by borehole and electromagnetic data. The results indicate that the local gravity highs may be the concentration of mineralized rocks with high density extending to depths of several hundred meters; the magnetic highs are related to mineralized rocks/intrusive rocks that are close to the surface. The tectonic framework of the whole ore bed is mainly controlled by NW‐SE, E‐W and NE‐SW structures, in which NE‐SW structures are related closely to mineralization and may provide optimum conditions for magma emplacement and fluid migration. Our research will help to study the tectonic evolution and guide further exploration of the deposit.

Geochemical anomalies are an important indicator in prospecting. In particular, geochemical anomalies of Cu play a very important role in geological prospecting of minerals. Geochemical anomalies of Cu are mainly related to mafic-ultramafic rocks and porphyry bodies, which are also associated with ore-forming elements of the Co-Zn-Cr-Ni-Cu combination. The conventional technique of geochemical prospecting involves superimposition of element symbols (Au, Fe, Cu, Al, Ca, etc.) on the geological map of an area by analysing geochemical anomalies using geochemical data. However, this technique is not suitable for regions where geochemical anomaly data are limited. The development of hyperspectral remote sensing has enabled the mapping of spectral features related to characteristic absorption bands of elements in minerals at high spatial resolution, providing a means for precise and detailed reconstructions of geochemical anomalies facies (surface). Compared to conventional techniques for identifying elements, reflectance spectroscopy offers a rapid, inexpensive, and non-destructive tool for determining the mineralogy of rock and soil samples. Hyperspectral remote sensing also provides data for prospecting in areas without sufficient geochemical data, and thus is of vital significance in prospecting for ores in such regions. However, approaches for remotely sensing elements are still lacking, particularly for element content. In this study, a level analysis of Cu content via spectral indices in the northwestern Junggar region, Xinjiang, was conducted. Based on four levels (0–100 ppm, 100–1000 ppm, 1000–10000 ppm, and >10000 ppm) of Cu content and corresponding spectral reflectance, simple and useful spectral indices for estimating Cu content at different levels were explored. The best wavelength domains for a given type of index were determined from four types of spectral indices by screening all combinations using correlation analysis. The coefficient of determination (R2) for Cu was calculated for all indices derived from the spectra of rock samples and was found to range from 0.02–0.75. With sensitive wavelengths and a significant correlation coefficient (R2 = 0.63, P < 0.005), the Normalized Difference (ND)-type index was the most sensitive to Cu content exceeding 10000 ppm. Although the ND-type index has a few limitations, it is a useful, simple, and robust indicator for determining Cu at high concentrations. With the advent of new platforms and satellites in the future, such relationships with other elements are required to enable the widespread use of this index in broad-scale surveys of mineral elements in the field.

Hatu and Baogutu are two typical gold deposits in the study area. Hatu gold deposit is associated with magmatism and controlled by regional-scale faults; mineralisation mainly occurs within hydrothermally altered felsic rocks and quartz veins. In the west region of the Hatu mining area, Cu, Ag, As and Sb are present in high concentrations in carbon tuffaceous shale. Baogutu gold deposit is associated with the evolution of felsic magmas, and the porphyry copper-gold mineralisation and copper-gold ore body dominated by sulphide were formed in the rock or near the contract zone in the faults, respectively. The ore-forming elements include Au, As and Sb. In this study, exploratory data analysis (EDA) and singularity mapping (SM) techniques were applied to identify geochemical anomalies caused by Au-related mineralisation according to stream sediment geochemical data set in Karamay mineral district, northwestern China. Silver, As, Au and Sb were chosen as indicator elements. The results show that EDA could not well identify weak anomalies within the strong variance of the background, while SM can recognise effectively weak anomalies, and quantify the properties of enrichment caused by mineralisation. The results obtained by SM demonstrated that the anomalies are closely associated with the known Au deposits in the study area. The anomalous areas delineated by the SM have potential for follow-up mineral exploration. In addition, the results document that Ag, As, Au and Sb may be reliable indicator elements for Au-related mineralisation in the study area.

Ecological capital assessment is currently one of the important research contents in the interdisciplinary field of ecology, resources economics, environmental economics and ecological economics. To scientifically assess ecological capital redounds to decision-makers to consider the ecological cost in economic development, and is also necessary for sustainable economic development in arid areas. Based on the theory of landscape ecology, in this paper the per unit area ecological capital values in arid areas are researched by using the Landsat TM data, CBERS satellite data, meteorological data, MODIS satellite data and other ecological data, and the RS-and GIS-based models of assessing ecological capital values in arid areas are developed. Moreover, based on the field-measured data, a case study on ecological capital assessment in the Manas River basin, Xinjiang in 2003 is carried out. The basin is divided into 4 ecological capital areas so as to quantitatively calculate the ecological capital values of the ecosystems, analyze the spatial distribution of ecological capital, and chart the maps of spatial distribution of ecological capital. The results show that the total ecological capital value of the ecosystems in the Manas River basin in 2003 was 1.494 54×1011 yuan RMB. In spatial distribution, the ecological capital decreases from the alpine zones to the plains and from the oases to the deserts, which accords with the distribution of vegetation zonality in this arid area. The assessed results can objectively reflect the ecological capital and its spatial distribution in the arid basin, and can also provide reference for roundly carrying out the assessment of ecological capital in arid areas.

The Tianshan Mountains is a high and huge mountain body lying across the central part of Xinjiang, China, and is also the main area where the runoff forms in Xinjiang. In this paper, a set of RS-based study methods is put forward for deriving the information about the natural change of the ecology in arid areas, and the relationship between the climate change trend and the corresponding ecological response on the northern slope of the Tianshan Mountains since recent 40 years is analyzed from the scales of the land cover ecosystems and landscapes based on the observed data of climate, hydrology, modern glaciers and lakes on the northern slopes of the Tianshan Mountains since recent 40 years and the satellite RS data since recent 10 years by using the RS and GIS technologies. The results are as follows: (1) The overall trend of climate change on the northern slope of the Tianshan Mountains since recent 40 years is that both air temperature and precipitation are increased, especially the increase amplitudes of air tempera-ture, precipitation and annual runoff volume are high since the decade of the 1990s; (2) the in-tegrated indexes of the vegetation in all the geographical divisions on the northern slope of the Tianshan Mountains are obviously increased since recent 10 years, especially in the artificial oases and the foothill belts, such a change trend is advantageous for improving the vegetation ecology; and (3) the vegetation ecology in the arid areas is extremely sensitive to the climate change, the vegetation coverage and the biomass on the northern slope of the Tianshan Moun-tains are continuously increased because of the climate change since recent 10 years, their in-crease amplitudes in the plains and during the late stage are obviously higher than that in the mountainous regions and during the early stage.

In order to predict the spatial distribution of land cover of different topographic factors, a quantitative research on the effects of elevation and slope factors on the process of land cover change during 1980-2007 were conducted using RS(remote sensing) and GIS(geographic information system) technology. Yuli county in Xinjiang is chose as the research area, two periods of MSS/TM remote sensing images in 1980 and 2007 and 1:50000 topographic map were taken as main data sources. The results showed that: during the past three decades: the area of cropland, forest-grass land, water, and construction land changed prominently, cropland mainly was converted into forest-grass land, water mainly converted into the forest-grass land; construction land expanded into the extent of high elevation; cropland and the construction land were distributed consistently on gradient, change trends of both land covers were identical, and expanded into the region of steeper slope; the forest-grass land with 3o; the water body kept reducing across the whole region. The changes of land use were mainly caused by topographic factors and social economy. It is feasible to predict the spatial distribution of land cover based on topographic data, remote sensing images and socioeconomic data, the results provided scientific basis for eco-environment evaluation and sustainable development in the region.

This research made use of the more accessible ETM+ remote sensing data and based on the previous methods to propose the MPS model and extract alteration information. The meaning of MPS model was mask process-principal component analysis-the support vector machine processing. This article applied and tested the methodology in the Hatu area, Xinjiang. Though the research, there was a better effect of extraction, and the outcome and the distribution of the mineral deposits was coherent well.

These GPS techniques can be stated as static, kinematic, semi-kinematic and on the other hand, with respect to the special precision requirements of different applications, they can also be stated as relative, absolute and DGPS techniques. RTK GPS has seen great technological advances over the past few years and is now routinely used in a wide variety of engineering type applications. evaluate RTK performance near the forest and in an urban environment under varying site conditions, and expected problems due to signal blockage and data latency.

Traffic accidents cause enormous losses for our country and plenty of national assets drain away every year, and therefore the task of traffic management is weightier than Mount Tai, but the complexity of traffic accident analysis has brought many difficulties to traffic management and decision-making. A three-layer analysis system based on spatial data mining of GIS is proposed in this paper, this three-layer architecture displays the whole process of accident data extracting, preprocessing and mining and it applies spatial data mining to GIS, which will certainly further expand the width and depth of GIS application field. Finally, this paper introduces the method of developing traffic accident analysis system by using ArcGIS Engine and C#.NET and gives the class realization of system main functions.

Sequential pattern has important applications in many areas and a large number of data and patterns need efficient and scalable parallel algorithm. In light of the widespread problem in current sequential pattern data mining algorithm and on the basis of researching the data mining algorithm of serial sequential pattern, a data mining algorithm of parallel sequential pattern is presented in this paper. Through theoretical analysis and experimental verification, the parallel data mining algorithm can well improve the efficiency of data mining in massive data circumstances.

Form the macroscopical-ecology point of view, base on remote sensing measure of region ecological capital evaluation's character, consider the possibility and reliability of acquire the data, we developed regional ecological capital assessment index in remote sensing measure. The paper calculate the total ecological capital from nine kind of ecological value. Base on the research achievements of the methodology of calculating per unit area ecological service value and the support of RS, GPS and GIS, the RS-based quantitative measurement of assessing the ecological capital developed by using the Landsat TM data, CBERS satellite data, meteorological data, MODIS satellite data and ecological data. We divided the study site to four ecological district and assess the ecological capital quantitative. A case study on the Spatial Analysis of the assessment of ecological capital in Changji Hui autonomous in 1990, 1995 and 2003 is carried out. Maps of the spatial distribution of ecological capital in the study area are charted, and the characteristics of the spatial distribution of ecological capital are analyzed.

Starting with the change of the land cover and the landscape patterns as well as the cold-island effect of the oasis, the temporal and spatial variation and the stability of the oasis of the alluvial-diluvial-fan/alluvial-plain type in the Sangong River watershed are researched by using the theories and methods of GIS, RS and landscape ecology based on the aerial photos in 1978 and 1987, the TM images in 1998 and the meteorological and hydrological data of the watershed. The results show that (ⅰ) the land cover of the whole oasis changes rapidly in a big amplitude, and there is an obvious temporal variation; (ⅱ) during the period of 1978—1987, the diversity and the variation of the oasis landscapes were increased but the stability of the oasis was decreased, the diversity of the oasis landscapes, however, has been decreased, but the stability has increased since 1987; (ⅲ) the cold-island effect of the oasis in the Sangong River watershed has been gradually increased since the 1960s, which reveals that the stability of the oasis has been obviously increased viewed from the angle of climate.