新疆西准噶尔苏云河斑岩型钼矿的剥露和保存条件:来自裂变径迹和(U-Th)/He热年代学的约束

斑岩型矿床多形成于汇聚型板块边界。由于其较浅的就位深度,大部分古老的斑岩型矿床很容易受到后期的剥蚀而消失殆尽。研究斑岩型矿床成矿后的埋藏和去顶过程对于深入理解矿床的保存条件和区域找矿前景至关重要。新疆西准噶尔西部的苏云河斑岩型钼矿床形成于晚石炭世,是一处保存良好的斑岩型矿床,为我们研究前中生代斑岩成矿系统的保存条件提供了天然的实验室。本文首次针对该矿床开展了锆石和磷灰石裂变径迹与锆石(U-Th)/He低温热年代学分析,结合热历史反演模拟以及前人的年代学数据显示,苏云河斑岩钼矿的蚀变过程至少持续了55Myr。在早二叠世到中三叠世,矿区接受5.2～8.1km厚的沉积物覆盖。中三叠世至早白垩世(240～120Ma),矿床经历了快速剥露作用,剥露速率为49.0～56.7m/Myr,去顶量为7.4～9.2km。早白垩世(120Ma)至今为缓慢剥露阶段,剥露速率为6.7～21.7m/Myr,去顶量为0.8～2.6km。中三叠世至早白垩世的快速冷却事件可能并不是特定构造事件(比如:南部羌塘和昆仑-柴达木碰撞或者羌塘和拉萨碰撞)远程效应的产物,而与区域内走滑断层的活化密切相关。而矿床早期沉积的巨厚盖层以及早白垩世以来干旱气候和缓慢剥露,为石炭-二叠纪斑岩型钼矿得以保存提供了条件。     

Active open boundary forcing using dual relaxation time-scales in downscaled ocean models

Regional models actively forced with data from larger scale models at their open boundaries often contain motion at different time-scales (e.g. tidal and low frequency). These motions are not always individually well specified in the forcing data, and one may require a more active boundary forcing while the other exert less influence on the model interior. If a single relaxation time-scale is used to relax toward these data in the boundary equation, then this may be difficult. The method of fractional steps is used to introduce dual relaxation time-scales in an open boundary local flux adjustment scheme. This allows tidal and low frequency oscillations to be relaxed independently, resulting in a better overall solution than if a single relaxation parameter is optimized for tidal (short relaxation) or low frequency (long relaxation) boundary forcing. The dual method is compared to the single relaxation method for an idealized test case where a tidal signal is superimposed on a steady state low frequency solution, and a real application where the low frequency boundary forcing component is derived from a global circulation model for a region extending over the whole Great Barrier Reef, and a tidal signal subsequently superimposed.     

广西钦州湾红树林抗菌活性菌株Erwinia sp. 5-8的筛选及发酵条件的优化

以金黄色葡萄球菌为指示菌,采用琼脂扩散法从国家海洋局海洋生物活性物质重点实验室广西钦州湾红树林微生物资源库中筛选获得一株具有明显抑菌效果的菌株5-8,对该菌株进行了分子鉴定与系统发育分析。结果表明,此菌为欧文氏菌属(Erwinia)。通过单因子试验对其发酵条件进行了优化,优化后发酵条件为:最佳氮源为蛋白胨,最佳碳源为葡萄糖,发酵培养基初始pH值为8.0,发酵温度为25℃,盐度为1.5,摇瓶装液量30%,接种量为1%(V种子液∶V培养液=1∶100)。     

山东省平邑县唐家崖石膏矿区东段水文地质特征分析

唐家崖矿区地处平邑凹陷的中偏西南部,石膏矿床为一中型内陆湖相沉积矿床。该文分析了矿床的水文地质条件和含水岩组及隔水岩组的含水特征。通过对充水因素的分析,根据边界条件确定了水文地质模型,选取了大井法预测矿坑的涌水量。并在此基础上确定了矿区的水文地质条件属中等类型。     

山东省肥城陆房地区萤石矿成矿地质条件及找矿方向

肥城陆房地区是一个重要萤石矿分布区,目前评价的2个萤石矿,分别位于九山和赵家庄矿区,赋存于二长花岗岩中,受NE,NNE向构造控制,均为岩浆热液充填型。从这2个萤石矿的矿床地质特征入手,结合国内已有萤石矿资料,分析肥城陆房地区的成矿地质条件及矿床成因,总结其成矿规律,并指出今后该区找矿方向。     

地理国情普查中解译样本数据检查技术探讨

地理国情普查项目中的遥感影像解译样本数据质量关乎普查产品质量。其数据的获取是普查工作的重要内容。普查数据的获取涉及面广,精度要求高,传统检查方式难于发现问题。文中通过ArcGIS自带的VBA脚本语言实现了数据库内容与照片和实例间的对应性检查;使用开源的GDAL库及C++语言实现了实例标注位置及裁剪范围的正确性检查。该技术使解译样本数据检查效率得到提高,同时检查精度及检查内容最大限度得到保证。     

高分遥感影像与矢量数据结合的变化检测方法

针对高分辨率遥感影像与矢量数据配准套合之后存在的不一致性问题,该文探讨了多尺度分割算法获取同质像斑的方法。在此基础上,发展了一种基于最近邻分类算法的分类后处理变化检测方法。结果表明,通过多尺度分割算法能够获取"类内光谱相同"和"类间光谱相异"的像斑;分类后处理变化检测方法能够正确检测出80%以上的变化区域,在获取变化检测结果的同时能够获取变化像斑的类别,而且检测精度较高,具有较高的应用价值。     

山东省枣庄市地质灾害现状研究及防治建议

在搜集、分析2020年以往资料的基础上,对枣庄市已知地质灾害点和新增地质灾害点进行核查、调查,最终保留地质灾害点80处.其中崩塌、滑坡和岩溶塌陷为小型规模,采空塌陷以大、中型规模为主.对地质灾害核查数据进行综合研究,总结分析枣庄市地质灾害分布特征和发育规律,对各区进行地质灾害易发程度综合分区评价,划分为高易发区、中易发...     

长江破碎带的研究过程及最新认识

本文依据南京市及其附近区域(活动断层探测目标区范围)所开展的浅层人工地震探测、槽探、钻探,以及第四纪地层划分、新年代学测试数据等多学科资料,综合评价了长江破碎带的最新活动年代、活动性质、断层相关参数及其与地震活动关系方面的最新认识。     

Formation of lunar mare domes along crustal fractures: Rheologic conditions, dimensions of feeder dikes, and the role of magma evolution

In this study we examine a set of lunar mare domes located in the Hortensius/Milichius/T. Mayer region and in northern Mare Tranquillitatis with respect to their formation along crustal fractures, their rheologic properties, the dimensions of their feeder dikes, and the importance of magma evolution processes during dome formation. Many of these domes display elongated summit vents oriented radially with respect to major impact basins, and several dome locations are also aligned in these preferential directions. Analysis of Clementine UV/VIS and Lunar Prospector gamma ray spectrometer data reveals that the examined mare domes formed from low-Si basaltic lavas of high FeO and low to moderate TiO₂ content. Based on their morphometric properties (diameter, height, volume) obtained by photoclinometric and shape from shading analysis of telescopic CCD images, we derive rheologic quantities (lava viscosity during eruption, effusion rate, duration of the effusion process, magma rise speed) and the dimensions of the feeder dikes. We establish three rheologic groups characterised by specific combinations of rheologic properties and dike dimensions, where the most relevant discriminative parameter is the lava viscosity η. The first group is characterised by and contains the domes with elongated vents in the Milichius/T. Mayer region and two similar domes in northern Mare Tranquillitatis. The second group with comprises the very low aligned domes in northern Mare Tranquillitatis, and the third group with the relatively steep domes near Hortensius and in the T. Mayer region. The inferred dike dimensions in comparison to lunar crustal thickness data indicate that the source regions of the feeder dikes are situated within the upper crust for six of the domes in northern Mare Tranquillitatis, while they are likely to be located in the lower crust and in the upper mantle for the other examined domes. By comparing the time scale of magma ascent with the time scale on which heat is conducted from the magma into the host rock, we find evidence that the importance of magma evolution processes during ascent such as cooling and crystallisation increases with lava viscosity. We conclude that different degrees of evolution of initially fluid basaltic magma are able to explain the broad range of lava viscosities inferred for the examined mare domes. The spectral data reveal that differences in TiO₂ content may additionally account for the systematic difference in lava viscosity between the two examined lunar regions. We show that the described mechanisms are likely to be valid also for other lunar mare domes situated near Cauchy and Arago, regarded for comparison. On the other hand, we find for the Gruithuisen and Mairan highland domes that despite their inferred high lava viscosities of , no significant magma cooling in the dike occurred during ascent, supporting previous findings that the highland domes were formed during a specific phase of non-mare volcanism by highly silicic viscous lavas.