Metallogenic focus-area and superlarge mineral deposits in the bordering zones between China,Russia and Mongolia

A correlative study of geology and metallogenic process in the bordering zones between China, Russia and Mongolia shows that the region of the western slope of the Da Hingan Mts. -Eastern Transbaikalia-Eastern Mongolia is a metallogenic focus-area associated with Late Mesozoic intraplate tectono-magmatic activation. During the period of 160–120 Ma a great number of multiplex deposits with similar genesis including large and superlarge mineral deposits were formed.

     

A comparative study of nutrient transfer via surface runoff from two small agricultural catchments in north China

A field study was conducted to determine the effect of landscape spatial pattern and micro-topography on nutrient transfer via runoff from two catchments into Yuqiao Reservoir in north China. The surface runoff discharge was measured during rainfall events and water samples were analyzed in 2004 and 2005. The mean annual total nitrogen (TN) and total phosphorus (TP) exports per unit area from Caogezhuang catchment (C catchment) were 1.048 and 0.561 kg ha⁻¹ year⁻¹, respectively, while the TN and TP exports from Taohuasi catchment (T catchment) were 0.158 and 0.027 kg ha⁻¹ year⁻¹. In both catchments, village and vineyard shared the highest nutrient export ability due to the accumulated animal waste and heavy application of fertilizer and manure. In T catchment, the distance of village and vineyard was about 1,500 m away from the receiving water and in between were woodland and cropland. In the hydrological pathway, there were sink landscape structures of small stone dams, roadside swale, vegetated filter strip and dry ponds, which could detain water and nutrients. In C catchment, the distance between the village and the receiving water was about 200 m, and the hydrological pathway was compacted roads and ditches with no sink structures. It is suggested that the distance between the pollution source area and the receiving water and the micro-topographical features were the main factors to control the great difference in nutrient export rates.     

Niobium-tantalum Fractionation During Slab Subduction:Implications for the Formation of Continental Crust

Compared with the oceanic crust, knowledge about the formation of the continental crust (CC) is relatively poor. Although melting of subducted slabs in the early history of the Earth has been considered as the major way that shaped the chemical characteristics of the CC by most geologists, as the CC shares many characteristics with modern adakites, some geologists argued that Archean TTG was formed in the same way as modern arcs rather than slab melting, whereas others proposed that melting at the bottom of the thickened oceanic crust was more important. Recently,the debate is mainly focused on the unique subchondritic Nb/Ta value of the CC, and particularly, how Nb and Ta fractionated from each other and consequently how, in detail, the CC was built.     

县(市)级国土资源部门的测绘管理

测绘行政管理对于县(市)级国土资源部门来说,是一个崭新的课题,作为《测绘法》赋予的可以履行测绘管理职能的最基层部门,如何在新的历史条件下充分发挥测绘管理的作用,不断将测绘管理事业推向前进,本文浅谈了几点看法.     

Seasonal variations in pCO2 and its controlling factors in surface seawater of the northern East China Sea

Surface partial pressure of CO₂ (pCO₂), temperature, salinity, nutrients, and chlorophyll a were measured in the East China Sea (ECS; 31°30′–34°00′N to 124°00′–127°30′E) in August 2003 (summer), May 2004 (spring), October 2004 (early fall), and November 2005 (fall). The warm and saline Tsushima Warm Current was observed in the eastern part of the survey area during four cruises, and relatively low salinity waters due to outflow from the Changjiang (Yangtze River) were observed over the western part of the survey area. Surface pCO₂ ranged from 236 to 445 μatm in spring and summer, and from 326 to 517 μatm in fall. Large pCO₂ (values >400 μatm) occurred in the western part of the study area in spring and fall, and in the eastern part in summer. A positive linear correlation existed between surface pCO₂ and temperature in the eastern part of the study area, where the Tsushima Warm Current dominates; this correlation suggests that temperature is the major factor controlling surface pCO₂ distribution in that area. In the western part of the study area, however, the main controlling factor is different and seasonally complex. There is large transport in this region of Changjiang Diluted Water in summer, causing low salinity and low pCO₂ values. The relationship between surface pCO₂ and water stability suggests that the amount of mixing and/or upwelling of CO₂-rich water might be the important process controlling surface pCO₂ levels during spring and fall in this shallow region. Sea–air CO₂ flux, based on the application of a Wanninkhof [1992. Relationship between wind speed and gas exchange over the ocean. Journal of Geophysical Research 97, 7373–7382] formula for gas transfer velocity and a set of monthly averaged satellite wind data, were −5.04±1.59, −2.52±1.81, 1.71±2.87, and 0.39±0.18 mmol m⁻² d⁻¹ in spring, summer, early fall, and fall, respectively, in the northern ECS. The ocean in this study area is therefore a carbon sink in spring and summer, but a weak source or in equilibrium with the atmosphere in fall. If the winter flux value is assumed to have been the mean of autumnal and vernal values, then the northern ECS absorbs about 0.013 Pg C annually. That result suggests that the northern ECS is a net sink for atmospheric CO₂, a result consistent with previous studies.     

上海市近百年来夏季降水时空分布特征及影响因素

依据前人的研究和上海1949-2005年气象资料,研究了上海地区夏季降水特征,结果显示:上海夏季降水在时间分布上具有周期性变化,在100多年中有3个多雨湿润期和3个少雨偏干期;在空间分布上,因城市"雨岛"效应影响,城市和郊区差异明显。太阳活动周期对降水存在周期性的影响,ENSO事件对降水多寡有影响,火山爆发使降水出现1~2 a的较短的周期波动。     

Fabric and crystal characteristics of Bohai and Arctic sea ice

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Sea-salt aerosol transport patterns over the Northern Hemisphere inferred from two subarctic ice core records

Ice core records provide the most direct, detailedand complete measure of past climate change[1,2]. Gla-ciochemical records have been used to investigate thechanges in atmospheric circulation patterns overGreenland Ice Sheet and West Antarctic[3—6]. Mostrecently, major ion series developed from new suban-nual scale sampling of GISP2 ice core from centralGreenland are calibrated with instrumental series ofsea level pressure (SLP) provide proxy records of ma-jor marine (Icelandic Low) and…     

MULTI—SOURCE REMOTE SENSING IMAGE FUSION BASED ON SUPPORT VECTOR MACHINE

Remote Sensing image fusion is an effective way to use the large volume of data from multi-source images.This paper introduces a new method of remote sensing image fusion based on support vector machine(SVM),using high spatial resolution data SPIN-2 and multi-spectral remote sensing data SPOT-4.Firstly,the new method is established by building a model of remote sensing image fusion based on SVM.Then by using SPIN-2 data and SPOT-4 data ,image classify-cation fusion in tested.Finally,and evaluation of the fusion result is made in two ways.1)From subjectivity assessment,the spatial resolution of the fused image is improved compared to the SPOT-4.And it is clearly that the texture of the fused image is distinctive.2)From quantitative analysis,the effect of classification fusion is better.As a whole ,the re-sult shows that the accuracy of image fusion based on SVM is high and the SVM algorithm can be recommended for applica-tion in remote sensing image fusion processes.     

地震趋势预测的一种新模型研究

 本文根据自激励门限自回归模型原理,对多年的地震活动形势进行了分析,建立了用于地震大形势分析的客观化数值预测模式-在线预测模型。根据1980年以来中国大陆实际发生的地震资料对这一模型的可靠性进行了检验。统计结果表明,利用在线预测模型在对未来地震趋势进行预测时,其年度形势特征量的最大误差为0.3,平均误差为0.12;因此该模型能够比较客观地反映地震形势变化的自然特征及规律,较好的预测未来的地震活动趋势。这一模型的建立为促进地震趋势向客观化、定量化预测方向发展,提供了一种科学途径