大别山的变质碰撞混杂岩——以东部为例

大别山是中国东部中朝大陆板块与扬子大陆板块之间的碰撞造山带。具有薄皮构造的性质。组成两个碰撞大陆之间的滑脱（冲断剪切）带的岩石就是碰撞混杂岩组合。大别山由于剥露较深,仰冲壳楔完全被剥蚀,超高压变质带大面积出露,识别出碰撞混杂岩组合是对大别山进行几何分析的必要步骤。大别山碰撞混杂岩组合可分为南北两部分。北部为条带状片麻岩-超镁铁岩组合,南部为云母斜长片麻岩-榴辉岩组合,这两个组合的大部分都经历过超高压变质作用。它们的共同特点是具有宏观的＂碎斑结构＂和混杂作用。罗田穹隆是造山过程中早期形成的双冲式背斜,最后在造山晚期因东西向缩短的叠加而形成穹隆。     

国家标准《国家基本比例尺地图编绘规范第1部分:1∶25 000 1∶50 000 1∶1 00 000地形图》修订说明

改变传统的地形图缩编工艺,利用已有的地形数据进行较小比例尺地形图的编绘已成为当前内业制图的主要作业方法。因此修订有关地形图编绘规范标准时应在编绘的作业方法与技术规定等方面适应数字地形图缩编的要求。介绍了该系列标准的结构调整及标准修订工作情况,提出了标准的修订原则,并对标准的修订进行了说明。     

准噶尔盆地中部III 区块原油中25-降藿烷分布特征与成因意义

通过对准噶尔盆地中部Ш区块原油或油砂抽提物的饱和烃气相色谱-质谱分析,研究了原油或油砂抽提物中25-降藿烷的分布规律.结果表明,不同井区或同一口井不同深度(层位)的原油25-降藿烷的相对含量存在比较明显的差别,表明其所遭受的生物降解程度有所差异,沿构造带从南到北,同一油层中原油的生物降解程度增强,比如位于构造北部(构造部位相对较高)的永1井、永3井侏罗系原油25-降藿烷丰度较高,表明生物降解比较明显,而位于南部(构造低部位)的永6井白垩系和侏罗系油层中的原油均无明显的生物降解现象;同一口井随深度增大生物降解作用将弱,如永2井浅部白垩系油层的原油降解较严重,而深部西山窑组的原油降解作用则不明显.根据原油生物降解的特征,结合车-莫古隆起调整对研究区油气成藏的影响,讨论了原油生物降解差异分布的成因机制.     

Quickbird遥感影象在土地利用类型整理中的应用——以四川遂宁市安居区为例

利用获取的四川遂宁市安居区东禅镇大面积相对准确的土地利用类型信息,建立土地分类的影象解译标志,然后在室内采用人工目视与人机交互式相结合的方法,提取土地利用现状信息。Quickbird影象分辨率高,但如何提高分类的精度和速度,是值得探讨的问题。     

动态最小二乘支持向量机学习算法

针对大样本集的训练问题和动态训练样本的模型更新问题,提出了动态最小二乘支持向量机学习算法.该算法充分利用已建好的模型,逐渐加入新样本,并可删除位于任何位置的非支持向量,避免了矩阵求逆运算,保证了算法的高效率.大坝变形及电离层延迟两个时间序列的预报实例表明,该算法具有计算时间短、预报精度高的特点.     

柴达木盆地西南部砂6井第三系沉积相研究

结合前人的研究成果,运用野外地质剖面、测井相标志的研究方法,对柴达木盆地西南第三系沉积相进行了较全面、系统的研究,描述了柴达木盆地砂6井第三系主要发育的三种沉积相及发育的主要类型,指出了研究区内有利于油气生成和储集的沉积相类型。     

追忆李四光对防震减灾的贡献,以系统整体观指导防震应急

笔者在追忆李四光地震科学和防震减灾指导思想的基础上,提出了以系统整体观指导防震应急的新论点,包括:运用地壳运动整体观研究地震规律;应用地震预测整体观进行地震预测;划分活动性构造体系,研究构造活动性;加强综合监测,研究各种地震前兆和相关的自然变异的发展趋势;圈定地震风险区,制定防震应急预案等.并结合中国的实际情况进行了论述.     

Interactive 3-D computation of fault surfaces using level sets

Deformable implicit surfaces, implemented with level set methods, have demonstrated a great potential in the computational sciences for applications such as modeling, simulation, and segmentation. They allow implicit handling of complex topologies deformed by operations where large changes can occur without destroying the level set representation. The use of level set techniques for the computation and segmentation of plane-like and high positive curvature features is nontrivial. We present a technique for representing and extracting fault surfaces from 3-D seismic attribute data such that 2-manifolds can be interactively computed and segmented. We present our approach as an interactive workflow that generates highly accurate fault surfaces.     

A virtual voyage through 3D structures generated by chaotic mixing of magmas and numerical simulations: a new approach for understanding spatial and temporal complexity of magma dynamics

In this contribution, we present a virtual voyage through 3D structures generated by chaotic mixing of magmas and numerical simulations with the aim to highlight the power of 3D representations in the understanding of this geological phenomenon. In particular, samples of mixed juveniles from Salina island (Southern Italy) are reconstructed in 3D by serial lapping and digital montage and numerical simulations are performed by using a 3D chaotic dynamical system. Natural and simulated magma mixing structures are visualized by using several multimedia tools including animations and “virtual reality” models. It is shown that magma interaction processes can generate large spatial and temporal compositional heterogeneities in magmatic systems. The same topological structures are observed in both 3D reconstructed rock samples and chaotic numerical simulations, indicating that the mixing of magmas is governed by chaotic dynamics. The use of 3D multimedia models gives the opportunity to penetrate into magma mixing structures and to understand their significance in the context of magma dynamics. Such an approach is very powerful since multimedia tools can strongly capture the attention of the reader bringing him/her into an interactive and memorable geological experience. Electronic supplementary material  enclosed: