Evolution of the ductile shear zone of the Paishanlou gold deposits,western Liaoning,China

The combination of field surveys with analysis of microstructure of tectonite and Electron Backscatter Diffraction (EBSD) on quartz fabric indicated that three periods of ductile shear events developed in the Paishanlou gold deposits and the E-W and NE-striking ductile shear zones were formed during each event. The E-W-striking ductile shear zone, accompanied by compressional and dextral shear slip, was shear-cut by the NE-striking shear zones, accompanied by compressional-sinistral shear slip and sinistral-normal shear slip, successively. An E-W-striking ductile shear zone developed at a deeper tectonic level and at middle- to high-temperatures, accompanied by abundant microstructures, including microlayering between a polycrystal quartz belt and mica, and quartz deformation was depended on cylinder (10-10) 〈a〉 or 〈c〉 glide. The development of an E-W-striking shear zone can be seen as a tectonic pattern in the region of the Paishanlou gold deposits of the collision between the Mongolian tectonic belt and the North Archean Craton from Suolun to the Linxi suture zone during the Indosinian. The NE-striking ductile shear zone developed approximately 160 Ma during the early Yianshanian at middle to shallow tectonic levels and at middle- to low-temperatures, accompanied by typical microstructures, including polycrystal quartz aggregation and quartz subgrain rotation recrystallization, etc., and quartz deformation was depended on prismatic (1011) 〈a〉 glide. The last ductile shear event around the NE-striking shear zone developed at low temperatures and shallow tectonic levels, yielding to a pre-existing NE-striking shear zone, accompanied by abundant microstructures, including low-temperature quartz grain boundary migration and bulging recrystallization. The last ductile shear movement may be related to lithosphere thinning and the destruction of the North China Craton from approximately 130-120 Ma, and this shear event resulted directly in the mineralization in the Paishanlou region.     

歧口凹陷新生界火成岩油藏特征及分布规律

歧口凹陷新生界发育了两类与火成岩相关的油藏：基性火山岩油藏和浅成侵入相辉绿岩蚀变带油藏,两者都为构造-岩性油藏。这两类油藏区域上受岩浆活动带控制,主要集中于NE向和EW向断裂转换带,并受烃源岩分布范围的影响而紧邻烃源岩分布;垂向上受区域盖层控制,集中于沙一中亚段和东三段。在转换带沙一中亚段和东三段内,火成岩能否富集成藏主要取决于储集系统的类型。开放式储集系统一方面利于流体替换使火成岩储集空间中的矿化水被及时排出减少次生矿物的形成,从而保护储集空间;另一方面利于富含有机酸流体进入火成岩储集体,通过溶蚀先期形成的杏仁体、裂缝充填物及火成岩中不稳定的矿物组分,使其储集空间扩大、容积增加,使火成岩的储集性能得以改善;另外,火成岩中的断裂通过与烃源岩的沟通为烃类注入富集成藏提供了必要的输导通道,致使这类储集系统能够富集烃类成藏。封闭式储集系统缺少这些条件,岩浆期后热液流体与成岩流体被包裹在火成岩储集空间内不能被排出,易形成次生矿物充填并堵塞这些空间,丧失其储集性能。部分未被充填的空间往往相互之间难以连通,并与生排烃地层隔绝而成为烃类难以注入的死孔隙,从而使这类储集系统难以聚集成藏。     

Geochemical baseline of trace elements in the sediment in Dexing area,South China

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr.     

基于事例推理技术的水库洪水调度研究与应用

将基于事例推理(CBR)技术应用到水库洪水调度中,提出了一种基于CBR的水库洪水调度模式和方法。利用关系数据库实现了洪水调度事例的表示、组织、索引和存储,并建立了水库洪水调度事例库。将遗传禁忌算法与最近相邻法结合起来,构建了基于遗传禁忌算法和最近相邻法相结合的混合检索算法,提高了事例检索的速度和质量。利用遗传算法对事例特征属性权重进行优化,采用多目标决策方法进行事例的优选,并给出了事例调整和学习的策略。最后,应用该方法开发了基于CBR的水库洪水调度系统,并给出了一个应用实例。基于CBR的水库洪水调度为水库洪水调度提供了一种简化知识获取、提高调度效率和质量、进行知识积累和重用的新的思路和方法。     

冕宁前寒武纪沉积岩的铕、铈异常特征及成因解释

冕宁尤黑木地区的前寒武纪沉积岩可分为碎屑沉积岩和化学沉积岩两类。前者具明显的负铕异常和不太明显的负铈异常;后者包括重晶石岩和碳酸盐岩,重晶石岩有较明显的负铕异常和负铈异常,碳酸盐岩具明显的负铈异常和不太明显的负铕异常。自碎屑沉积岩经重晶石岩至碳酸盐岩,稀土总量及负铕异常依次降低,负铈异常则明显增大,反映出铕、铈异常的负相关关系。     

实验水槽常规流速模拟的缩尺方法

提出了一种实验室水槽中流速模拟的方法,该方法可根据需要提供合适的模型缩尺比,用来完成相关海洋工程的模型水动力性能实验,可以近似地模拟出实际设备在水中的工作状态,为在实验水槽中模拟水流动力参数提供有效的参考,方便水槽中的科学实验的开展。     

植被状态指数VCI与几种气象干旱指数的对比——以河南省为例

使用1982-2006年GIMMS AVHRR NDVI数据集与同期的CI、K、Pa、SPI、Z、PDSI等干旱指数做了对比分析, 讨论了河南省植被状态指数VCI对气象干旱的滞后效应及干旱监测能力. 结果表明: VCI指数与气象干旱指数的相关性受不同下垫面的影响较大, 农地的VCI与气象干旱指数相关性要明显高于林地, 农地VCI与气象干旱指数呈现正相关关系. 在河南省不同的作物生长阶段, VCI对气象干旱有着不同的滞后效应, 其中, 3-5月份冬小麦生长期VCI对气象条件的反应滞后1~3个月, 7、9月份夏玉米生长期VCI对气象条件的反应滞后1月. 总体上看, 结合前期的气象数据, VCI对河南省气象干旱有一定的指示作用和监测能力.     

Diagnosis of river basins as CO2 sources or sinks subject to sediment movement

Sediment movement during erosion, transport and deposition greatly affects the ecosystem of river basins. However, there is presently no consensus as to whether particular river basins act as carbon dioxide (CO₂) sources or sinks related to these processes. This paper introduces a rule‐of‐thumb coordinate system based on sediment delivery ratio (SDR) and soil humin content (SHC) in order to evaluate the net effect of soil erosion, sediment transport and deposition on CO₂ flux in river basins. The SDR–SHC system delineates CO₂ source and sink areas, and further divides the sink into strong and weak areas according to the world‐average line. The Yellow River Basin, most severely suffering soil erosion in the world, only appears to be a weak erosion‐induced CO₂ sink in this system. The average annual CO₂ sequestration is ~0·235 Mt from 1960 to 2008, a relatively small value considering its 3·1% contribution to the World's sediment discharge. The temporal analysis shows that the Yellow River Basin was once a source in the 1960s, but changed its role to become a weak sink in the past 40 years due to both anthropogenic and climatic influences. The spatial analysis identifies the middle sub‐basin as the main source region, and the lower as the main sink. For comparison, sediment‐movement‐related CO₂ fluxes of eight other major basins in four continents are examined. It is found that the six basins considered in the Northern Hemisphere appear to be sinks, while the other two in the Southern Hemisphere act as sources. Copyright © 2012 John Wiley & Sons, Ltd.     

黑龙江省科洛火山群火山地质研究

科洛火山群的新生代火山共有23座,坐落于科洛河两岸,火山岩面积约为350km2,岩性主要为碱性玄武岩.由于地处NE向断陷盆地这一特殊的构造位置,科洛地区的火山活动及展布主要受到区域基底断裂的制约.火山喷发形式总体为中心式,属斯通博利式火山.火山活动可划分为上新世、更新世和全新世3期.上新世在断陷盆地边缘形成了一系列NE向线性展布的中心式溢出型火山,其中部分火山因风化剥蚀而失去了原有的火山地貌特征,仅保留盾形熔岩台地.早更新世火山活动相对平静.中-晚更新世火山活动仍受到NE向基底断裂的控制,但喷发中心、喷发方式及喷发强度均发生改变,火山由碱玄质火山渣锥和熔岩流组成.进入全新世以后南山喷发,其火山结构保存完好,裸露的熔岩台地保留了较好的微地貌特征.该期火山亦由碱玄质火山渣锥和熔岩流构成.在科洛火山群的火山活动过程中,其熔岩流覆盖了早期沉积地层,并对盆地中的河流进行了改造,最终导致该区断陷盆地初始地貌的改变.