基于深度学习的介形类化石层次化识别

介形类化石对地质年代的确定、古湖泊和古海洋的研究、古环境的重建以及海底石油资源的勘探等工作都具有重要意义.然而,现有识别化石颗粒的方法费时费力,准确率也有待提高.鉴于介形类化石颗粒的类别具有科、属、种的层次结构,种类数量庞大,所以笔者等提出了一种层次化识别方法.首先进行目标检测,实现介形类化石的定位与属类划分;之后在目...     

数量化理论在泥石流易发性预测中的应用

泥石流易发性是泥石流研究中的重点与难点,泥石流易发性的确定对于泥石流整体特征的把握具有十分重要的作用。在总结现行标准和前人研究不足的基础上,从发生学角度选取流域面积、纵坡降、谷坡坡度等9个评价指标,采用数量化理论Ⅰ建立了泥石流易发性预测模型。通过模型自检和应用验证结果表明,模型准确率分别达到87.14%和90%,证明了该方法在泥石流易发性评价中的合理性与有效性。     

祁县井水温和水位的奇异潮汐关系探讨

Tidal phase of water temperature in Qixian well, Shanxi Province is ahead of water level, which is different from the normal tidal relationship between water temperature and water level. Observation curves of this phenomenon are introduced in this paper, and co-seismic response data of water temperature and water level are used to check the thermometer time system, confirming that this phenomenon is true. Using the harmonic analysis method, variations of time difference between water temperature and water level for the M2 wave are worked out, which indicates that this phenomenon exists during the whole observation. According to the variations of phase lags for water temperature and water level, and the survey of observation conditions, it is considered that the abnormal phenomenon may be related to inadequate passage of water caused by a well blockage at the depth where the water temperature probe was set.     

玉树台井水温变化及其与青藏块体周缘大地震间的关系

分析了2008~2015年间玉树台井水温变化趋势,发现有5次异常变化,其中4次与青藏块体及周缘的大地震活动有一定相关性。对水温异常变化幅度、异常出现时间与震级以及井震距的进一步分析发现,玉树台井水温变化幅度随井震距的减小而增大;从异常出现时间来看,震级越大,从异常出现到地震发生的时间间隔越短。     

汶川8.0级地震氡震后效应机理讨论

在汶川地震氡震后效应特征的分析研究的基础上,对氡震后效应变化规律及机理展开了初步的探讨。按水氡阶变上升速度与恢复时间的长短,近场水氡震后效应可分为短期恢复型与长期不恢复型,远场水氡震后效应可分为短期恢复型与长期不恢复型。针对氡震后效应的4种变化规律,提出了4种可能的机理:破裂混合机理、破裂射气增大机理、振动射气增大机理、裂隙开启-闭合机理。研究氡震后效应变化规律及其机理,是从另一角度探讨氡的来源、迁移、表现与应力-应变、含水层动力学特征之间的关系,为氡地震前兆机理的研究与前兆异常判定提供一定的理论依据。     

Cenozoic Mineralization in China, as a Key to Past Mineralization and a Clue to Future Prospecting

Many Cenozoic metal deposits have been found during the past decade. Among them, the Fuwan Ag deposit in Guangdong is the largest Ag deposit in China. Besides, the largest Cu deposit of China in Yulong, Tibet, the largest Pb-Zn deposit of China in Jinding, Yunnan, and the largest Au deposit of China in Jinguashi,Taiwan, were also formed in the Cenozoic. Why so many important "present" deposits formed during such a short period of geological history is the key problem. The major reason is that different tectonic settings control different kinds of magmatic activity and mineralization at the same time. In southwestern China, porphyry-type Cu deposits such as Yulong were formed during the early stage of the Himalayan orogeny, sediment-hosted Pb-Zn deposits such as Jinding were formed within intermontane basins related to deep faults, and carbonatite-related deposits such as the Maoniuping REE deposit and alkalic magmatic rock-related deposits such as the Beiya Au deposit originated from the mantle source.     

Episodes of Cenozoic Gold Mineralization on the Eastern Margin of the Qinghai-Tibet Plateau:~(40)Ar/~(39)Ar Dating and Implication for Geodynamic Events

A lot of new gold deposits have been found on the eastern margin of the Qinghai-Tibet Plateau during the past two decades. Among them, three main types of gold deposits have been recognized, including quartz-vein-type, shearzone-type and porphyry-type. The former two types of gold deposits are mainly hosted within metamorphic rocks, while the latter is related to Cenozoic magmatism. Although all of these gold deposits are believed to have been formed during the uplift process of the Qinghai-Tibet Plateau in the Cenozoic era (Wang et al., 2002b), precise isotopic age constraints have still been lacking until quite recently. This paper presents new ^40Ar/^39Ar data of some gold deposits on the eastern margin of the Qinghai-Tibet Plateau, which indicate that gold mineralization in the region occurred in response to the episodic stages of the orogenies. Recently obtained ^40Ar/^39Ar data on quartz and feldspars from several gold deposits, such as the Sandiao deposit, the Baijintaizi deposit, the Pusagang deposits, provide new constraints on gold mineralization on the eastern margin of the Qinghai-Tibet Plateau. Geochronological studies of gold deposits along the Daduhe River indicate that there are three stages of gold mineralization. The early two stages occurred as early as 65.1 Ma in the Shuibaiyang deposit and 58.95 Ma in the Ruoji deposit, while the latter stage occurred as late as 25.35 Ma in Baijintaizi and 24.70 Ma in Sandiao. Isotopic dating of three plagioclases from the Beiya deposit, Zhifanggou deposit and Luobodi deposit and a K-feldspar from the Jinchangqing deposit in Yunnan Province indicates that these deposits were formed at two stages. The Zhifanggou and Jinchangqing deposits have early stage records as old as 58.82 Ma in Zhifanggou and 55.49 Ma in Jinchangqing, but all of the above four deposits in Yunnan have late stage records of 23.18 Ma in Jinchangqing, 24.54 Ma in Zhifanggou, 24.60 Ma in Luobodi and 24.56 Ma in Hongnitang. The above results suggest that the gold deposits on the eastern margin of the Qinghai-Tibet Plateau were formed concentratedly at two main episodes, i.e. the end of the Paleocene (about 58 Ma) and the boundary between the Paleogene and the Neogene (about 25 Ma). The later episode appears to be looks like more important and was coupled with the Sichuan movement, which was extensively activated at that period. The beginning of the Cenozoic Era (about 65 Ma) might be another episode of gold mineralization, but only one deposit (Shuibaiyang) in this study has been proved to have been be formed at this stage and might be earlier than the initial collision between the Indian Plate and the Eurasia Plate. In view of geology, the above three episodes of gold mineralization are associated with three events of tectonicmagmatism and/or fluid events. Even though the gold deposits (for example, the Shuibaiyang deposit, Ruoji deposit and Pusagang deposit) were formed at different episodes, all of them are genetically related to tectonic movements in largescale shear zones. It looks like theat tectonic events (including large-scale strike-slip) between Paleogene and Neogene had a wide influence upon gold mineralization, with new deposits formed and old deposits enriched or superimposed to be a higher grade by new stage of mineralization. The above data suggest that gold deposits were not only concentrated in some areas, but also formed mainly at different boundaries of geological times, indicating that there existed some peak stages of gold mineralization (metallogenic episodes), and that the gold deposits were formed mainly by episodic mineralization.     

中国铜矿成矿规律概要

中国铜矿资源丰富.本文在对全国814处铜矿床及其他5000余个矿(化)点资料系统梳理的基础上,完善了对中国铜矿产预测类型的划分方案,分为10个类型,认为斑岩型、矽卡岩型应该作为重点预测类型;其中又以斑岩型铜矿资源最主要,集中分布于冈底斯、昌都-三江、德兴、东天山等地区;成矿时代以新生代和中生代最为重要.系统搜集了全国范围内有关铜矿床的成矿年代学资料,划分为4个铜的主要成矿期;厘定出27个以铜为主的矿床成矿系列,提升了我国铜矿成矿规律研究的程度,为我国铜矿资源的潜力评价预测工作提供了理论依据.     

40Ar/39Ar and Rb-Sr Ages of the Tiegelongnan Porphyry Cu-(Au) Deposit in the Bangong Co-Nujiang Metallogenic Belt of Tibet, China: Implication for Generation of Super-Large Deposit

The Tiegelongnan deposit is a newly discovered super-large porphyry-epithermal Cu-(Au) deposit in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet(China). Field geology and geochronology indicate that the porphyry mineralization was closely related to the Early Cretaceous intermediate-felsic intrusions(ca. 123–120 Ma). Various epithermal ore and gangue mineral types were discovered in the middle-shallow part of the orebody, indicating the presence of epithermal mineralization at Tiegelongnan. Potassic, propylitic, phyllic and advanced argillic alteration zones were identified. ~(40)Ar/~(39)Ar dating of hydrothermal biotite(potassic zone), sericite(phyllic zone), and alunite(advanced argillic zone) in/around the ore-bearing granodiorite porphyry yielded 121.1±0.6 Ma(1σ), 120.8±0.7 Ma(1σ) and 117.9±1.6 Ma(1σ), respectively. Five hydrothermal mineralization stages were identified, of which the Stage IV pyrite was Rb-Sr dated to be 117.5±1.8 Ma(2σ), representing the end of epithermal mineralization. Field geology and geochronology suggest that both the epithermal and porphyry mineralization belong to the same magmatic-hydrothermal system. The Tiegelongnan super-large Cu-(Au) deposit may have undergone a prolonged magmatichydrothermal evolution, with the major mineralization event occurring at ca.120–117Ma.     

与海相火山作用有关的铁-铜-铅-锌矿床成矿系列类型及成因初探

文章初步厘定了与海相火作用有关的铁、铜、铅、锌矿床成矿系列类型的概念，并对其进行了分类，讨论了其成因，认为内生外成（沉）是其主要特征，即成矿物质主要由火山作用从深部提供，而矿石又是通过沉积作用在海底形成的。在一定程度上，可从成矿类型的角度将块状硫化物矿床与BIF型或磁铁石英岩型矿床联系起来考虑。该类矿床成矿系列类型的演化特点在一定程度上可以反映地球演化的历史轨迹。