辽南金州拆离断层带中花岗质岩石的变形:显微构造、组构与年代学分析

花岗岩(脉)在中下地壳韧性剪切带中普遍发育,如何正确鉴别剪切带中剪切前、剪切期及剪切后花岗岩(脉)以及正确理解剪切过程中构造变形与岩浆作用之间的关系一直是一个重要课题。本文以辽南金州拆离断层带为研究对象,选取中部地壳伸展作用过程中具有不同变形表现的花岗岩(脉)开展宏观-微观构造观察、石英EBSD组构分析及锆石LA-ICP-MS年代学测试等工作,从而进一步丰富构造-岩浆关系判别准则。剪切前花岗岩(脉)多变形强烈且具有后期固态变形叠加在早期高温岩浆组构之上的特点,而剪切期的花岗岩由于侵位的时间不同,岩石的变形程度也会不同。剪切晚期侵入的岩脉遭受了较弱的晶内塑性变形,而剪切早期的岩脉可以显示岩浆流动或结晶后高温至中温固态变形。从组构特点上看,剪切前和剪切期花岗质岩石石英c轴组构大多表现为中高温组构叠加有低温组构的特点。剪切后的花岗质岩石仅发生微弱的晶内变形或未变形而显示低温或无规律的组构特征。对五个典型的样品进行年代学测试,其结果符合相应的期次划分类型。应用宏观构造、显微构造与组构分析,结合年代学测试综合分析,对于辽南变质核杂岩构造-岩浆活动性进行了精细划分,包括134~130Ma初始伸展阶段,130~115Ma峰期伸展与强烈岩浆活动阶段,以及115Ma前后伸展作用结束。     

基于生态水力学法的金沙电站最小下泄流量计算

最小下泄流量的确定是环境影响评价工作的重点,以金沙水电站为例,采用生态水力学法,在综合评判河段水深、流速、水面宽、湿周率、过水断面面积等水力参数以及水力形态要素的基础上,确定金沙水电站最小下泄流量,以满足下游河道鱼类生产繁衍的必要条件。     

景洪市嘎栋地热井特征及成井工艺总结分析

景洪盆地内蕴藏有丰富的地热资源。通过对景洪市嘎栋地热资源勘查地热井地质、施工情况及成果进行介绍,结合勘查施工实践,针对地热资源勘查开发、地热钻井施工、成井工艺及钻井过程中地质问题等有关内容进行经验总结并分析,对地热地质条件与地热井施工之间结合进行一些经验探讨,并对现行地热井规范中关于井身结构设计、取水层位确定、单井资源量计算等问题提出一定疑问。旨在通过实践及疑问探讨,力图找出为地热资源勘查开发提供值得借鉴的经验和教训。     

从同震和震后形变分析1668年M8.5级郯城地震对周边地震活动性的影响

以山东郯城1668年大地震为例,以前人地表地质调查结果为约束,利用弹性位错理论初步获取了该地震的同震破裂模型;在此基础上,基于粘弹性分层模型分析了该地震的同震和震后形变,同时以主震断层为接收断层计算了库仑应力分布,进一步讨论了地幔不同粘滞性系数对地表形变和库仑应力变化的影响。计算结果显示,该地震是一个右旋走滑为主兼有一定逆冲性质的地震,其同震位移巨大,能量释放较彻底;同震破裂造成震中郯城县西北、东北和南部部分断层库仑应力增加,而震后形变使得这些断层库仑应力进一步增加,在单县、宿迁和日照等地,地震后350 a库仑应力变化量达到+1bar-+1MPa量级;地幔粘滞性系数不同,形变量和库仑应力变化达到稳定的时间不同,但最终趋于稳定的数值基本一致。     

养殖曼氏无针乌贼(Sepiella japonica)的两性异形及判别模式的建立

两性个体的有效鉴别是曼氏无针乌贼高效繁育及养殖模式(如单性养殖)建立的基础。为研究曼氏无针乌贼主要形态指标及雌雄形态差异,测量了160只F1代曼氏无针乌贼的19项可测量性状及13项标准化性状。采用聚类分析、主成分分析和判别分析方法研究了曼氏无针乌贼同生群两性间的形态差异。结果表明:两性间可测量性状和标准化性状各有10项有显著性差异(P0.05);对标准化性状经过主成分分析和R-聚类分析均显示曼氏无针乌贼的两性的差异主要集中在辅助交配器官特征,头部特征,捕食器官和肥瘦特征以及体型特征等4个方面。在此基础上,通过逐步判别法从标准化性状中筛选出3项,即左3腕长/胴长、左4腕长/胴长及左触腕长/胴长,建立了雌雄的判别方程:雄性:F1=223.42X3+165.85X4+7.951X5–108.06;雌性:F2=151.48X3+92.71X4+19.19X5–60.38。所建立的判别方程,对样本群体的综合判别率达到95.00%。利用F2代亲体测量数据对判别函数进行识别验证,综合判别率达到85.34%。在判别方程中的3个标准化性状中,左3腕长/胴长和左4腕长/胴长在两性亲体间均存在显著的差异(P0.05),表明曼氏无针乌贼的雄性在性选择的作用下,交配器官存在显著差异。     

天津市滨海新区芦苇湿地恢复适宜性评价

利用综合评价模型,结合地理信息系统技术的空间分析功能,以土地利用、土壤类型、坡度、降雨量和人类干扰活动作为评价因子,对天津滨海新区芦苇湿地恢复进行了适宜性评价。结果表明,较适宜开展湿地恢复的比例为21.46%,一般适宜比例为21.87%,不适宜比例占56.68%,其中较适宜湿地恢复的区域集中分布在北大港湿地自然保护区周边、独流减河下游、北塘入海口以及沿海滩涂,海河流域两侧也有零星分布。在适宜性评价基础上,对未来芦苇湿地恢复与建设的重点区域进行了成效预评估,芦苇对TC、TN、TP的年吸收通量约为1.3935×104、0.0258×104、0.0017×104t,能有效地减少入海排污压力和污染物对近岸海域环境质量的影响。研究结论可为天津湿地治理与生态恢复、土地利用结构调整、景观优化等提供理论依据和科学参考。     

Hydrothermal Fluid Sources of the Fengjia Barite–fluorite Deposit in Southeast Sichuan,China: Evidence from Fluid Inclusions and Hydrogen and Oxygen Isotopes

The Fengjia barite–fluorite deposit in southeast Sichuan is a stratabound ore deposit which occurs mainly in Lower Ordovician carbonate rocks. Here we present results from fluid inclusion and oxygen and hydrogen isotope studies to determine the nature and origin of the hydrothermal fluids that generated the deposit. The temperature of the ore‐forming fluid shows a range of 86 to 302 °C. Our detailed microthermometric data show that the temperature during mineralization of the fluorite and barite in the early ore‐forming stage was higher than that during the formation of the calcite in the late ore‐forming stage. The salinity varied substantially from 0.18% to 21.19% NaCl eqv., whereas the density was around 1.00 g/cm³. The fluid composition was mainly H₂O (>91.33%), followed by CO₂, CH₄ and traces of C₂H₆, CO, Ar, and H₂S. The dominant cation was Na⁺ and the dominant anion Cl^‐, followed by Ca²⁺, SO₄^2‐, K⁺, and Mg²⁺, indicating a mid–low‐temperature, mid‐low‐salinity, low‐density NaCl–H₂O system. Our results demonstrate that the temperature decreased during the ore‐forming process and the fluid system changed from a closed reducing environment to an open oxidizing environment. The hydrogen and oxygen isotope data demonstrate that the hydrothermal fluids in the study area had multiple sources, primarily formation water, as well as meteoric water and metamorphic water. Combined with the geological setting and mineralization features we infer that the stratabound barite–fluorite deposits originated from mid–low‐temperature hydrothermal fluids and formed vein filling in the fault zone.     

基于层次分析法的德州地面沉降易发区的可拓学划分应用

基于物元模型的可拓学理论分析,提出华北平原德州地面沉降易发区的可拓学划分方法。利用地面沉降易发性分级、分类标准和影响因子分析,构造出经典域物元和节域物元,应用物元和可拓集合中的关联函数,建立了易发性等级综合评判的可拓评价模型,通过基于层次分析法的可拓学评价分析,采用正方形等间距(2km×2km)剖分了135个网格,再将剖分单元转化成面元,经过等值差分,得到了地面沉降易发区划结果。计算结果显示,可拓学方法能够实现定量化、多因子评价地面沉降易发性等级问题,从而科学合理地指导地面沉降综合分区防治。     

Approximate optimal tracking control for near-surface AUVs with wave disturbances

This paper considers the optimal trajectory tracking control problem for near-surface autonomous underwater vehicles (AUVs) in the presence of wave disturbances. An approximate optimal tracking control (AOTC) approach is proposed. Firstly, a six-degrees-of-freedom (six-DOF) AUV model with its body-fixed coordinate system is decoupled and simplified and then a nonlinear control model of AUVs in the vertical plane is given. Also, an exosystem model of wave disturbances is constructed based on Hirom approximation formula. Secondly, the time-parameterized desired trajectory which is tracked by the AUV’s system is represented by the exosystem. Then, the coupled two-point boundary value (TPBV) problem of optimal tracking control for AUVs is derived from the theory of quadratic optimal control. By using a recently developed successive approximation approach to construct sequences, the coupled TPBV problem is transformed into a problem of solving two decoupled linear differential sequences of state vectors and adjoint vectors. By iteratively solving the two equation sequences, the AOTC law is obtained, which consists of a nonlinear optimal feedback item, an expected output tracking item, a feedforward disturbances rejection item, and a nonlinear compensatory term. Furthermore, a wave disturbances observer model is designed in order to solve the physically realizable problem. Simulation is carried out by using the Remote Environmental Unit (REMUS) AUV model to demonstrate the effectiveness of the proposed algorithm.