河西走廊城镇地貌特征分析与开发评价

本文阐述了河西走廊城镇的地貌特征,从建设开发的角度分析评价城镇地貌特征并提出了今后合理发展的方向与对策。     

塔里木盆地城镇的地域演化

分析了塔里木盆地城镇从原始聚落，西域三十六国，西汉屯垦聚落到汉后多中心城镇和近代环状城镇格局的地域演化过程及现代城镇地域分布的变化及其特点。     

Statistical Comparison of Geophysical Parameters and Seismicity in Central Italy

Geological and geophysical data of an area of central Italy have been used for statistically comparing with the distribution of the mean seismic deformation. This parameter has been calculated by adding the square root of the energy released by earthquakes inside a cell, the dimensions of which have been fixed after performing an analysis of spatial autocorrelation. Underground temperatures, fault length, and topographic altitude showed a good single linear correlation with seismicity. Factor analysis has been employed to reduce the number of original variables, taking into account their mutual correlation; then, with the new uncorrelated variables, a good multiple linear correlation has been found, considering seismic deformation as a dependent variable.The analysis of residuals for the multiple regression shows the existence of areas with different seismic activity than predicted by the model: a discussion of the residuals pattern follows, considering the geological setting of the area.     

Fluid migration and vein formation during deformation and greenschist facies metamorphism at Ormiston Gorge, central Australia

During the Alice Springs Orogeny, deformation at Ormiston Gorge, central Australia, occurred under lower- to middle-greenschist facies conditions. Dolomites of the Bitter Springs Formation and quartzites. metagreywackes, and metapelites of the Heavitree Quartzite contain abundant early-, syn-, and post-tectonic veins. However, though vein densities locally approach 15%, the distribution of veins and the oxygen isotope geochemistry of wallrocks and veins suggest that fluid movement was on a local scale. The Heavitree Quartzite contains quartz veins that, even along the main thrust plane, have similar δ¹⁸O values (13.5–16.9%o) to those of their wallrocks (13.6–16.9%o), with Δ¹⁸O(vein-wallrock) values of -0.6 to 0.4%o. In contrast, the Bitter Springs Formation contains predominantly dolomite veins that have δ¹⁸O values of 23.4 to 27.7%o. These differences are observed even at the boundary between the Heavitree and Bitter Springs rocks, implying that significant fluid exchange between these rocks has not occurred, or that fluid flow was channelled through areas outside those sampled for this study. By contrast with the Heavitree Quartzite, δ¹⁸O values of wallrocks in individual samples of the Bitter Springs Formation are significantly higher (23.3–29.1%o) than those of the veins, with δ¹⁸O(vein-wallrock) values up to -4%o (average of -2.1%o). These systematic differences in δ¹⁸O values most likely result from oxygen isotope fractionation caused by fluid immiscibility or disequilibrium dissolution. Smaller differences in δ¹³C values between some dolomite veins and wallrocks [δ¹³C(vein-wallrock) up to -1.9%o, average of -0.5%o] are also explained by these processes. This study indicates that large volumes of veins may be produced by repeated fracturing and fluid migration within particular rock units, without involving large volumes of externally derived fluids.     

全球变化生物迁移和地层界线──论希腊雅典地区第四系底界

全球环境的突然变化，可能引起全球性生物多样性跃升、全球性生物群体绝灭及生物群全球性迁移。为了阐明生物群的全球性迁移，我们应用了气候带中心种群及气候带边界种群的新概念。在第四纪初期，全球开始变冷，北半球寒冷气候带的生物群向南扩张，温带、亚热带乃至热带的生物群向南退缩，在这呈带状的整体的扩张和退缩过程中，气候带的边界种群总是比气候带的中心种群先期到达同一地区。就同一地区而言，边界种群的迁入，代表该区气候开始变冷，而中心种群的到达，则表示该区气候已进入最冷期，所以我们建议以气候带边界种群首次移入该区的时限，作为该区第四纪的开始。依据这一原理，我们把北温带北部的边界种Ｅｌｐｈｉｄｉｕｍｃｒｉｓｐｕｍ／ｍａ－ｃｅｌｌｕｍＳｐｅｃｉｅｓＧｒｏｕｐ在希腊雅典东Ｒａｆｉｎａ沿岸地区首次出现，作为该区第四纪的开始。     

县域城镇体系规划中城镇化水平研究：以新源,乌苏,吉木萨尔三县为例

城镇化水平是县域城镇体系规划中一个重要的量化指标，也是衡量一个区域社会经济发达程度的重要指标，本文从城镇化涵义入手规定理论上城镇人口的统计口径，提出求算实有城镇人口的公式Ｐ＝Ｎ．Ｋ，即利用城镇非农业人口数为基数Ｎ，再依据各县实际情况确定系数Ｋ值，二者相乘作为县域实有城镇人口Ｐ，以此测算出的县域城镇化水平比较贴近实际，并证明它是目前一种较为理想的方法。     

The Role of the Halted Baroclinic Mode at the Central Equatorial Pacific in E1 Nifio Event

The role of halted “baroclinic modes” in the central equatorial Pacific is analyzed. It is found that dominant anomaly signals corresponding to “baroclinic modes” occur in the upper layer of the equatorial Pacific, in a two-and-a-half layer oceanic model, in assimilated results of a simple OGCM and in the ADCP observation of TAO. A second “baroclinic mode” is halted in the central equatorial Pacific corresponding to a positive SST anomaly while the first “baroclinic mode” propagates eastwards in the eastern equatorial Pacific. The role of the halted second “baroclinic mode” in the central equatorial Pacific is explained by a staged ocean-atmosphere interaction mechanism in the formation of El Ni?no: the westerly bursts in boreal winter over the western equatorial Pacific generate the halted second “baroclinic mode” in the central equatorial Pacific, leading to the increase of heat content and temperature in the upper layer of the central Pacific which induces the shift of convection from over the western equatorial Pacific to the central equatorial Pacific; another wider, westerly anomaly burst is induced over the western region of convection above the central equatorial Pacific and the westerly anomaly burst generates the first “baroclinic mode” propagating to the eastern equatorial Pacific, resulting in a warm event in the eastern equatorial Pacific. The mechanism presented in this paper reveals that the central equatorial Pacific is a key region in detecting the possibility of ENSO and, by analyzing TAO observation data of ocean currents and temperature in the central equatorial Pacific, in predicting the coming of an El Ni?no several months ahead.     

Coccolithophores from the central Arabian Sea: Sediment trap results

Sediment trap samples collected from a depth of 1018 m in the Central Arabian Sea Trap (CAST) at 14°28.2′N, 64°35.8′E were analyzed for temporal variation of coccolithophore fluxes from October 1993 to August 1994. Out of the twenty species of coccolithophores encountered,Gephyrocapsa oceanica, Emiliania huxleyi, Umbilicosphaera sibogae andUmbellosphaera irregularis were the most abundant. The total coccolithophore fluxes ranged from 28.5 × 10⁶m^-2d^-1 to 50.3 × 10⁶m^-2d^-1 showing seasonality with higher fluxes during the northeast (NE) monsoon and lower fluxes during the spring intermonsoon. The higher fluxes were attributed to the enhancement of primary production in the central Arabian Sea due to southward extent of nutrients from the northeast Arabian Sea by the prevailing surface currents. Similarly, the occurrences of relatively lower coccolithophore fluxes during the spring intermonsoon and southwest (SW) monsoon were attributed to the low nutrients in the warm, shallow surface mixed layer and downwelling to the south of Findlater Jet respectively in the central Arabian Sea. Some of the coccolithophore species such asE. huxleyi, G. oceanica, Calcidiscus leptoporus andUmbellosphaera tenuis showed signs of dissolution.     

汾阳市杏花村镇供水井位勘测

传统直流电法勘探方法,在地下水研究中应用于寻找水源、确定地下水的开采量取得了较好的应用效果.本文结合杏花村镇供水井位勘测,详细介绍了地球物理勘探工作的方法,并对测量资料进行了解释,提出了确定供水井井位的建议.