Table of Content

    25 March 2006, Volume 61 Issue 3 Previous Issue    Next Issue
    The Distribution and Protection of the Geological Heritages in Xinjiang
    HUANG Song
    2006, 61 (3):  227-240.  doi: 10.11821/xb200603001
    Abstract ( )   PDF (964KB) ( )   Save

    The development of protection on geological heritage reflects the gradual progress at home and abroad from the protection alone to coordination of protection and exploitation. In the geopark construction by UNESCO, geological heritage protection was closely combined with promotion of sustainable development of local economy, which has become the best way to protect the geological heritage. The geological heritages in Xinjiang are great in quantity, vary in type and excellent in grade. The complicated geologic-geomorphic environment decided the type and spatial distribution of the geological heritages in Xinjiang, where the main types are geologic/geomorpohologic landscapes and water landforms. The spatial distribution can be divided into five geological heritage provinces, i.e., the Altai, Zhunggar, Tianshan, Tarim and Kunlun-Altun, among which Tianshan and Kunlun-Altun are most important. According to the first systematical investigation of the geological heritage in Xinjiang, it is confirmed that poor coordination between protection and development is the basic reason for the falling behind situation in geological heritage protection. Six major protection steps are identified, that is, protection type, protection form, protection mode, protection grade, protection priority scheduling and protection zoning. At the same time the optimal-selection thought, which integrates geopark with geological heritage protection area and other dependent territories as well as five modes are put forward. Therefore, the protection and development reserve list of 209 important geological heritages in Xinjiang is constructed.

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    Developments of Alluvial Fans and Their Catchments in Houma Basin
    LI Xinpo, MO Duowen, ZHU Zhongli
    2006, 61 (3):  241-248.  doi: 10.11821/xb200603002
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    We collected indexes of alluvial fans and their drainage basins from DEM data, and analyzed distribution of these indexes. By comparison of distribution curves of these indexes with elevation distribution curve of piedmont landforms, we did some research on the developments of alluvial fans and their drainage basins. As a result, we find that the alluvial fans and their drainage basins in the uplift region of Houma basin differ greatly from those in the sunken region; distributions of drainage basin indexes are mainly influenced by tectonic activity of boundary fault; alluvial fans are influenced by factors of drainage basin, tectonic movement of boundary fault and base level together; and lithological difference between rocks and underlying drainage basins is not the main factor leading to difference in alluvial fans in the study area.

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    Formation of the Zagunao River Terraces in Western Sichuan Plateau, China
    LIU Yong, ZHAO Zhijun, LI Cailin, ZHANG Maoheng, CHEN Ye
    2006, 61 (3):  249-254.  doi: 10.11821/xb200603003
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    Our field investigation identified eight river terraces at Zagunao, Lixian county of Western Sichuan Plateau along the Zagunao River, a main tributary of the Minjiang River. Applying ESR dating method, we successively determined ages of T2, T3, T4 and T6, which are 54, 125, 248 and 481 ka BP respectively. The development of the terrace sequences here was prominently under the control of regional tectonic uplift, and they should record phased uplift events of the Western Sichuan Plateau since the middle Pleistocene. The average incision rate of Zagunao River is calculated to be around 0.39 m/ka, which is coincident with the geodesic uplift rate of the Longmen Mountain (0.3-0.4 m/ka).

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    Environmental Archaeology on the Rise and Decline of Ancient Culture around 2000BC in the Yishu River Basin
    GAO Huazhong, ZHU Cheng, CAO Guangjie
    2006, 61 (3):  255-261.  doi: 10.11821/xb200603004
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    Neolithic culture series in Yishu River basin developed in the order of Dawenkou culture-Longshan culture-Yueshi culture. In the period of Dawenkou culture, the ancient culture developed rapidly. During the period of Longshan culture, the ancient culture reached climax, having a magnificent time. The ancient culture decayed significantly in Yueshi culture period. According to the study on the records of environmental changes about Yishu River basin, using 14C dating, δ13C, grain size, magnetic susceptibility and geo-chemical analysis, we acquired high-resolution sequence of environmental changes from 2970BC to 1050BC: 2970BC-2260BC, the climate of study area was warm and wet; 2260BC-1880BC, the climate had a mutation with an extensive temperature drop; and 1880BC-1050BC, the climate changed greatly. During the early and middle stage of Longshan culture (2600BC-2300BC), the climate in the Yishu River basin was warm and wet. Paddy-oriented agriculture planted paddy was very well developed. The society was flourishing with great amount of archaeological sites. The cooling starting in 2260BC made the paddies shortfall in output or even no seeds were gathered. This situation intensified the discrepancy between population and resource. The scarcity in natural resources led to susbstantial decrease in population and subsequent drop in archaeological sites. About 2000BC Longshan culture was displaced by Yueshi culture which was relatively underdeveloped, simple and unsophisticated.

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    The Driving Forces of Environmental Change during the Last 50 Years in the Tarim River Basin
    HAO Xingming, CHEN Yaning, LI Weihong
    2006, 61 (3):  262-272.  doi: 10.11821/xb200603005
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    Based on the data of hydrology, vegetation and socio-economy during the last 50 years in the Tarim River Basin, this paper estimated the impact of anthropogenic activities on surface runoff through trend analysis, and measured the relationship between factorsof anthropogenic activities and surface runoff and groundwater quality by correlation analysis and principal component analysis. The results showed that during the past 50 years the headstream's runoff didn't decrease but increased and the mainstream's runoff decreased due to anthropogenic activities. The proportions of impact of anthropogenic activities on the mainstream's runoff are 41.59%, 63.77% and 75.15% respectively during the 1970s, 1980s and 1990s. The main factor that affects water quality in the watercourse is the decreasing surface runoff induced by anthropogenic activities, and the main factor that affects water quality in irrigated and non-irrigated areas is groundwater level. In fact the ecosystem's degeneration in the lower reaches of the Tarim River is directly correlated with anthropogenic activities.

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    Uncertainty Analysis in Estimating the Minimum Ecological Instream Flow Requirements via Wetted Perimeter Method: Curvature Technique or Slope Technique
    LIU Suxia, MO Xingguo, XIA Jun, LIU Changming,LIN Zhonghui, MEN Baohui, JI Lina
    2006, 61 (3):  273-281.  doi: 10.11821/xb200603006
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    By comparing the two techniques to determine the critical point on the relationship curve between wetted perimeter and discharge for the estimates of the minimum ecological instream flow requirement (MEIFR), the uncertainty of the wetted perimeter method is analyzed. Under the assumptions of the triangular cross section channel and the uniform stable flow, an analytical solution of MEIFR is deduced. It is clearly shown that the results of MEIFR based on curvature technique (corresponding to the maximum curvature) and slope technique (slope being 1) are significantly different. It is found that the slope of the transition point with the maximum curvature is 0.39 and the MEIFR varies prominently with the variation of the slope threshold. This notes that if a certain value of the slope threshold is not available in the slope technique, the results of MEIFR via curvature technique by the wetted perimeter method are more certain. By applying the analytical solution of MEIFR in the rivers of Western Route South-to-North Water Transfer Project in China, it shows that the MEIFR value via curvature technique is 2.5%-23.7% of the multi-year average annual discharge, while that for slope technique is 11%-105.7%. This paper starts the research from the simple triangular cross section channels. More general conclusions rely on the more detailed research on various sections.

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    Drastic Decrease in Sediment Supply from Yangtze River and Coastal Crisis
    LI Ming, YANG Shilun, LI Peng, LIU Zhe, DAI Shibao, GAO Ang, ZHANG Jing
    2006, 61 (3):  282-288.  doi: 10.11821/xb200603007
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    The periodicity and trends of 1951-2004 time series of water and sediment discharges at Datong Station and precipitation in the catchment were analyzed using wavelet method. Bathymetric data were processed for coastal area and profile using Arc-GIS software. A typical intertidal flat was daily measured from May 2002 to August 2005 for comparison of bed level between pre- and post-impoundment of the Three Gorges Reservoir. The results indicate that the sediment discharge shows a decreasing trend from the late 1960s (P < 0.001) while it varies in periods of 2-3 years and 8-9 years together with water discharge and precipitation. The decreasing trend is attributed mainly to dam construction while the periodicity is attributed to climate variability. After the impoundment of the Three Gorges Reservoir, the sediment discharge was reduced to the lowest level in the history. As a result of the drastic decrease in riverine sediment supply, the delta is transforming from progradation to recession. The sediment supply from the Yangtze is forecasted to decrease from 1.5×108-2×108 t/a at the present to -1×108 t/a in the coming decades, which will result in crisis of coastal resources.

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    Calculation Method on Ecological Pondage and Ecological Water Requirement of Marsh
    LI Jiuyi, LI Lijuan, JIANG Dejuan, YANG Junwei
    2006, 61 (3):  289-296.  doi: 10.11821/xb200603008
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    Marsh is one of the most typical wetlands, playing important roles in hydrological and economic aspects, especially in keeping biological diversity. In this study, the definition and category of the ecological pondage of marsh have been discussed for the first time, and the distinction and relationship with ecological water requirement have been analyzed. Furthermore, the gist and method of calculating ecological pondage and ecological water requirement have been provided, and Zhalong wetland has been given as an example of calculation of the two variables. Ecological water use of marsh can be ascertained according to ecological pondage and ecological water requirement, and the suitable quantity can be calculated basing on the marsh's water condition and the total water quantity, insuring that the pondage changes reasonably in spatial and temporal scale, so that the rational water allocation can be achieved.

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    A Survey of Arsenic Concentrations in Vegetables and Soils in Beijing and the Potential Risks to Human Health
    CHEN Tongbin, SONG Bo, ZHENG Yuanming, HUANG Zechun,ZHENG Guodi, LI Yanxia, LEI Mei, LIAO Xiaoyong
    2006, 61 (3):  297-310.  doi: 10.11821/xb200603009
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    In order to assess the risks to human health posed by elevated concentrations of arsenic in vegetables, and to identify pollution-tolerant vegetable varieties, a large scale survey of arsenic levels in soils and vegetables planted or sold in Beijing was conducted. Thirty-nine soil samples were collected from gardens and fields used to grow vegetable plants. In addition, 93 varieties of more than 400 fresh vegetable samples were obtained from vegetable stalls, supermarkets and wholesale outlets. Arsenic concentrations were measured using hydride generation atomic fluorescence spectroscopy (HG-AFS). Arsenic concentrations in soils ranged from 4.44 to 25.3 mg kg-1, with arithmetic and geometric means of 9.40 and 8.79 mg kg-1, respectively. Compared with the background arsenic concentrations of soil from Beijing, there appeared to be a significant accumulation of arsenic in soil collected from gardens/fields that produce vegetables. Arsenic concentrations in the edible plant portions ranged from less than the analytical detection limit (0.1 μg kg-1 fresh weight) to 0.479 mg kg-1 fresh weight, with a mean of 0.028 mg kg-1 fresh weight. In all of the samples, arsenic was less than the Tolerance Limit of Arsenic in Foods for China (TLAFC) of 0.5 mg kg-1 fresh weight. The TLAFC is the maximum permissible concentration of arsenic in vegetables that will be consumed by people. The highest level of arsenic detected in a vegetable plant was 0.479 mg kg-1, which was measured in a radish (Raphanus sp.) sample obtained from the Fengtai District of Beijing. Arsenic was detected at 0.331 mg kg-1 in a garlic sample collected from Shandong Province, which is higher than the standard of 0.25 mg kg-1 set by WHO/FAO. The spatial distribution of arsenic concentrations in vegetables planted in Beijing presented apparently a "U-shaped" pattern at the northeast deflection angle of 11o-30o. The arsenic concentration in field-grown vegetables was significantly higher than the concentration of those planted in a greenhouse.Results of hierarchical cluster analysis on the arsenic bioconcentration factor (BCF) in vegetables indicated that the plants sampled could be separated into two groups based on BCF. Rape (Brassica campestris), radish (Raphanus sp.), pakchoi (Brassica chinensis), onion (Allium fistulosum), mustard (Brassica juncea), cucumber (Cucumis sativus), Chinese cabbage (Brassica pekinensis) and cabbage (Brassica caulorapa) had higher arsenic BCFs while chili (Capsicum annuum), beans round trellis (Vigna unguiculata), wax gourd (Beninacasa hispida), eggplant (Solanum sp.), spinach (Spinacia oleracea), tomato (Lycopersicon esculentum) and celery (Apium graveolens) had lower arsenic BCFs. The average ingestion rate of arsenic from vegetables was 0.016 mg/person/day for people of Beijing. Consuming vegetables with elevated arsenic concentrations may pose a health risk to local residents, particularly the young, elderly, or ill.

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    Gray Correlative Analysis of the Impact from Growing Urbanization Process on Pedodiversity in Nanjing Area
    SUN Yanci, ZHANG Xuelei, CHENG Xunqiang, Wang Hui, TAN Manzhi, CHEN Jie
    2006, 61 (3):  311-318.  doi: 10.11821/xb200603010
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    More and more natural soil resources have been occupied by the rapid urbanization in the Yangtse Delta. Based on the data of TM images (30m×30m) of three different periods (1984, 1995 and 2003), this paper analyzed the expansion of Nanjing area in the past 20 years using the method of multi-source information integration and multi-phase-successive -comparison with the aid of RS and GIS techniques. Combined with the soil map of Nanjing, we calculated the pedodiversity (HP), evenness (Jsw) and richness (R2) indices of Nanjing by the diversity measure methods borrowed from biological studies. Then it studied the spatial-temporal dynamic change of pedodiversity pattern in Nanjing area. Finally, it explored the impact of urbanization on pedodiversity with gray correlative analysis model. The result shows that the expansion of different administration units has various impacts on pedodiversity with village, the most significant impact, sharing 60%, town about 26%, city 7%, and county 7% of the total study area.

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    Changes of Cotton Climate Risk Degree in Henan Province
    QIAN Huaisui, REN Yuyu, Li Mingxia
    2006, 61 (3):  319-326.  doi: 10.11821/xb200603011
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    Basing on previous researches, this article established the cotton climate suitability model and the risk index to analyze the cotton climate risk degree in Henan Province. The result shows: in the last 40 years, the cotton climate risk degree presents a gradual increasing tendency in which the precipitation plays a very important role, and the climate suitability and its change have different performance to the risk change influence in different phases; the increase rate of risk degree is significantly regional and transitional. For example, from the eastern plain to the western mountainous area, the risk change rate becomes slower and slower, so the contrast of the central-southern Huang-Huai plain and Funiu highland is most remarkable; and in the north-south direction, the contrast between the fast increase belt from the central-southern Huang-Huai plain to the middle Yellow River and the slow increase belt from the northern side of the middle Yellow River to the lower Yellow River bank is especially remarkable, being possibly the results of topographic and climatic transitional belt; and the risk change process also has obvious regional differences. For instance, jumping change is an important characteristic in eastern Henan, while in the western mountainous area it is very rare. Although the 40 years changing tendency in this area is still increasing, the tendency has reduced gradually since the end of the 1980s, i.e. this sudden change type has obvious latitudinal difference.

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    Review of Studies in Climate Change over the Tibetan Plateau
    LI Chaoliu, KANG Shichang
    2006, 61 (3):  327-335.  doi: 10.11821/xb200603012
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    As the "third pole" of the world, the Tibetan Plateau has important effects on climate in its surrounding areas and the whole world. Achievements have been gained on climate change since the last inter-glacial period in recent decades from ice core, tree-ring, and lake sediment records over the Tibetan Plateau. In this paper, we reviewed these achievements, especially those in the special periods. During the last inter-glacial period, temperature dropped rapidly and rose slowly. The temperature record of the last glacial period is consistent with Greenland ice core records, also having its own trait over the Tibetan Plateau. Younger Dryas event agrees with the records from Europe and Greenland. It is warm generally in Holocene, and temperature has been rising in the last 2000 years and gone up rapidly in the last decades. Climate changes at different scales on the Tibetan Plateau occur earlier and the extent is greater than that in other parts of China.

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