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Journal of Geographical Sciences - In this study, we developed an energy security evaluation model (ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and... 相似文献
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Linglin Chu Andreas Enggist Robert W. Luth 《Contributions to Mineralogy and Petrology》2011,162(3):565-571
To examine the effect of KCl-bearing fluids on the melting behavior of the Earth’s mantle, we conducted experiments in the
Mg2SiO4–MgSiO3–H2O and Mg2SiO4–MgSiO3–KCl–H2O systems at 5 GPa. In the Mg2SiO4–MgSiO3–H2O system, the temperature of the fluid-saturated solidus is bracketed between 1,200–1,250°C, and both forsterite and enstatite
coexist with the liquid under supersolidus conditions. In the Mg2SiO4–MgSiO3–KCl–H2O systems with molar Cl/(Cl + H2O) ratios of 0.2, 0.4, and 0.6, the temperatures of the fluid-saturated solidus are bracketed between 1,400–1,450°C, 1,550–1,600°C,
and 1,600–1,650°C, respectively, and only forsterite coexists with liquid under supersolidus conditions. This increase in
the temperature of the solidus demonstrates the significant effect of KCl on reducing the activity of H2O in the fluid in the Mg2SiO4–MgSiO3–H2O system. The change in the melting residues indicates that the incongruent melting of enstatite (enstatite = forsterite + silica-rich
melt) could extend to pressures above 5 GPa in KCl-bearing systems, in contrast to the behavior in the KCl-free system. 相似文献
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Phase relations of phlogopite with magnesite from 4 to 8 GPa 总被引：2，自引：2，他引：0
Andreas?EnggistEmail author Linglin?Chu Robert?W.?Luth 《Contributions to Mineralogy and Petrology》2012,163(3):467-481
To evaluate the stability of phlogopite in the presence of carbonate in the Earth’s mantle, we conducted a series of experiments
in the KMAS–H2O–CO2 system. A mixture consisting of synthetic phlogopite (phl) and natural magnesite (mag) was prepared (phl90-mag10; wt%) and run at pressures from 4 to 8 GPa at temperatures ranging from 1,150 to 1,550°C. We bracketed the solidus between
1,200 and 1,250°C at pressures of 4, 5 and 6 GPa and between 1,150 and 1,200°C at a pressure of 7 GPa. Below the solidus,
phlogopite coexists with magnesite, pyrope and a fluid. At the solidus, magnesite is the first phase to react out, and enstatite
and olivine appear. Phlogopite melts over a temperature range of ~150°C. The amount of garnet increases above solidus from
~10 to ~30 modal% to higher pressures and temperatures. A dramatic change in the composition of quench phlogopite is observed
with increasing pressure from similar to primary phlogopite at 4 GPa to hypersilicic at pressures ≥5 GPa. Relative to CO2-free systems, the solidus is lowered such, that, if carbonation reactions and phlogopite metasomatism take place above a
subducting slab in a very hot (Cascadia-type) subduction environment, phlogopite will melt at a pressure of ~7.5 GPa. In a
cold (40 mWm−2) subcontinental lithospheric mantle, phlogopite is stable to a depth of 200 km in the presence of carbonate and can coexist
with a fluid that becomes Si-rich with increasing pressure. Ascending kimberlitic melts that are produced at greater depths
could react with peridotite at the base of the subcontinental lithospheric mantle, crystallizing phlogopite and carbonate
at a depth of 180–200 km. 相似文献
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伊犁地块南缘元古宙特克斯群变质岩中侵入有花岗岩类，其形成时代和构造背景一直没有详细的研究。文章通过野外观察和室内分析，确定花岗质侵入体主要由弱面理化黑云母花岗岩、强面理化二云母花岗岩和未变形黑云母花岗岩组成。全岩地球化学和锆石U-Pb年代学分析显示，弱面理化黑云母花岗岩和强面理化二云母花岗岩属于过铝质钙碱性系列，其年龄分别为438 Ma和426 Ma；未变形黑云母花岗岩则属于典型的钙碱性系列，富集大离子亲石元素，相对亏损高场强元素，其年龄介于400~380 Ma之间。结合前人对区域地质的研究认识，笔者认为这些花岗岩类记录了两期不同构造背景的岩浆作用，指示研究区经历了两阶段构造—岩浆演化，即早古生代过铝质钙碱性弱面理化黑云母花岗岩与强面理化二云母花岗岩形成于哈萨克斯坦微大陆汇聚拼贴过程的后碰撞造山环境；中—晚古生代钙碱性未变形黑云母花岗岩则形成于准噶尔洋俯冲作用的活动大陆边缘。 相似文献
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湘西汞矿床的地质特征与成因 总被引：2，自引：0，他引：2
湘西汞矿床是湘黔汞矿带的重要组成部分.湘西汞矿受层位和构造双重控制,与岩浆活动没有直接联系,具有层带式整合矿体,矿物成分简单,汞锌矿化分带及后生成矿等地质特征.矿石硫来源于古海水硫酸盐的沉积硫;而汞的来源.则以上地幔去气作用产生的汞为主,寒武系等富汞建造的汞次之.燕山期地台活化时,以硫络合物或硫氢络合物的形式,在碱性溶液中沿深大断裂向上运转,当其与富含膏盐的客矿层相遇时,便与还原硫结合沉淀成矿.形成湘西层控后生汞矿床. 相似文献
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大气气溶胶的监测对全球气候变化、区域空气质量和公共健康等研究具有重要的意义,而中国台湾岛四面环海,地理位置特殊,若忽略其大气环流和局地排放源造成的气溶胶特征时空异质性将会导致气溶胶参数反演误差。因此本研究使用中国台湾岛多个具有代表性的AERONET（AErosol RObotic NETwork）观测站历史数据和MODIS气溶胶光学厚度AOD（Aerosol Optical Depth）反演产品,分析5个典型站点气溶胶参数及其类型的时空变化特征及差异,分析结果表明：（1）各站点AOD年平均值逐年下降,呈现春季最高（0.5257）的季节变化特征和双峰结构的日变化规律,主导气溶胶类型为城市工业型（仅鹿林站点为海洋型）。（2）中国台湾地区风向多为东北风,风速越大,AOD值越低,海洋型气溶胶占比越高;反之则以城市工业型气溶胶为主。（3）?ngstr?m波长指数（AE）、单次散射比（SSA）、复折射指数虚部、不对称因子平均值分别为1.3283、0.9564、0.0054、0.7292;相比于北京（39.9768°N,116.3813°E）站,台湾“中央大学”AOD年平均值、季节变化、主导气溶胶类型均存在较大的差异。（4）MODIS AOD分站点验证精度较高,而在高山鹿林站的验证精度稍低（R2=0.5925）;而利用不同气溶胶类型的分类验证结果显示,城市工业（R2=0.7238）、生物质燃烧（R2=0.6161）和次大陆型（R2=0.5116）精度较高,但海洋型（R2=0.1585）、大陆型（R2=0.1111）AOD验证精度显著降低。本研究表明,中国台湾岛气溶胶类型呈现西南沿岸站点秋冬季次大陆型占比上升,西北沿岸大陆型上升的时空特征差异,细化气溶胶参数的时间差异和时间动态变化信息将对气溶胶卫星反演算法在环流特征明显的近海区域有着重要指导作用。 相似文献
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Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production. 相似文献