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61.
在那丹哈达地区采集了中三叠世红色硅质岩样品,古地磁分析测试结果表明,该岩样的磁性特征与日本西南美浓地区同时代硅质岩具有相似性,反映了二者是同源同构造环境下的产物。依据沉积地层组合和古地磁数据,那丹哈达和日本美浓地区原为同一地体,而且三叠纪以来均存在大规模北向位移。同时,古地磁数据还表明了日本海是约在80Ma,相当于晚白垩世开始扩张的,致使那丹哈达与日本美浓两地体相互分离 相似文献
62.
北山地区照壁山金矿床地质特征及成因 总被引:2,自引:1,他引:2
照壁山金矿床是北山地区中部金矿集中区最具代表性的金矿床之一,金矿化主要在黑云母花岗岩株内或沿其与志留系公婆泉群火山-沉积岩的接触带产出,黑云母40Ar-39Ar同位素年龄为296±5 Ma.金矿体主要由含金石英脉,网脉和细脉浸染状块体组成,金属矿物主要有黄铁矿、方铅矿、闪锌矿、黄铜矿、自然金和银金矿,脉石矿物为石英和绢云母.围岩蚀变自含金矿脉(体)向外,分别为硅化、绢云母化和绿泥石化;另外,沿岩体与火山-沉积岩接触带常可观察到黄铁绢英岩化.微量元素和硫、氧、氢及铅同位素数据表明:黑云母花岗岩是同碰撞造山期深源岩浆与地壳物质相互作用的结果,成(岩)矿物质主要来自壳幔混合源,含矿热液是岩浆热流体与大气降水混合的产物.海西期花岗质岩浆活动不仅为金矿床的形成提供了物质和热力来源,而且是成矿热液对流循环的"发动机",成矿体系温、压降低是导致金沉淀与富集的重要控制因素. 相似文献
63.
中国东北松辽盆地晚白垩世青山口组浮动天文年代标尺的建立 总被引:8,自引:3,他引:5
松辽盆地上白垩统青山口组主要由深湖相黑色泥岩、页岩组成,是大庆油田最重要的烃源岩之一,但长期以来对其年代学框架存在很大争议。对松辽盆地"松科1井"南井(茂206井)自然伽马测井和密度测井数据进行小波分析和连续滑动窗口频谱分析,表明茂206井青山口组记录了稳定的Milankovitch旋回。由长、短偏心率、地轴斜率和岁差周期造成的地层旋回厚度分别为39、13.5~9、5~3.8和2.5~1.7m。茂206井青山口组沉积速率变化不大,平均沉积速率为9.63cm/ka,沉积时限为5.16Ma。通过对长、短偏心率周期进行高斯带通滤波,建立了茂206井青山口组的"浮动"天文年代标尺。青山口组共记录了12.7个长偏心率周期和47.7个短偏心率周期。确定出青山口组1段下部油页岩层段对应的古湖泊缺氧事件(LAE1)持续时间约为250ka,与白垩纪Cenomanian-Turonian时期第二次大洋缺氧事件(OAE2)的持续时间接近。青山口组天文年代标尺的确立为约束青山口组沉积期各种地质事件的持续时间提供了年代学依据。 相似文献
64.
65.
In human cognition, both visual features (i.e., spectrum, geometry and texture) and relational contexts (i.e. spatial relations) are used to interpret very-high-resolution (VHR) images. However, most existing classification methods only consider visual features, thus classification performances are susceptible to the confusion of visual features and the complexity of geographic objects in VHR images. On the contrary, relational contexts between geographic objects are some kinds of spatial knowledge, thus they can help to correct initial classification errors in a classification post-processing. This study presents the models for formalizing relational contexts, including relative relations (like alongness, betweeness, among, and surrounding), direction relation (azimuth) and their combination. The formalized relational contexts were further used to define locally contextual regions to identify those objects that should be reclassified in a post-classification process and to improve the results of an initial classification. The experimental results demonstrate that the relational contexts can significantly improve the accuracies of buildings, water, trees, roads, other surfaces and shadows. The relational contexts as well as their combinations can be regarded as a contribution to post-processing classification techniques in GEOBIA framework, and help to recognize image objects that cannot be distinguished in an initial classification. 相似文献
66.
67.
从当前技术能力角度分析烟幕在海上作战中的运用,特别是信息化条件下烟幕在反侦察、防空反导等领域下的作用。主要根据现代烟幕的能力,重点分析烟幕在海上作战时的使用方法和使用时机等问题,并探索其运用的方法手段,可为海上作战中烟幕运用提供一定思路。 相似文献
68.
69.
Xu Shihong Wang Yanfeng Gao Caixia Babu V Sarath Li Jun Liu Qinghua Xiao Zhizhong Xu Yingxuan Zhao Chunyan Lin Li Chi Liang 《中国海洋湖沼学报》2023,41(1):364-375
Journal of Oceanology and Limnology - Dissolved oxygen (DO) is one of most important factors which affect wide range physiologic features of fish, including immune responses and intestinal... 相似文献
70.
The Xiong’ershan area,as a part of a metallogenic province in cetral China,contains substantial Leimengou porphyry molybdenite deposit,Qiyugou breccia gold deposits and vein gold deposit occurred in fault zone,as well as previously refer to as orogenic gold deposit.Around or nearby the Mesozoic porphyry granite,the typical porphyry deposit,much more breccia pipes and breccia gold deposit are developed in the area.In this paper we focus on reporting preliminary results obtained from field,petrographic work on the Leimengou porphyry molybdenite and the Qiyugou breccia gold deposit,as well as laser Raman microspectroscopy and microprobe analyses carried out on samples from the Au-bearing Qiyugou breccia pipes.An adularia-calcite assemblage is reported in these breccia gold deposits.Two stages of hydrothermal alteration,pervasive and vein,are identified.The first stage consists of the alteration of the breccia clasts and rock flour by actinolite,green biotite,epidote,chlorite and minor sericite.This hydrothermal activity is likely to relate to the molybdenite mineralisation episode.The second stage is characterised by quartz veining and adularia and calcite filling open-spaces.Vein ores associated with quartz,sericite,and minor calcite alteration occur in NE-trending fault that cut the first stage of alteration.The adularia-calcite alteration is genetically associated with gold mineralization.The adularia-calcite assemblage in the area suggest that the Qiyugou pipes are of low-sulphidation epithermal in nature.The Qiyugou breccia pipes are coeval and spatially associated with the nearby Leimengou porphyry Mo deposit,which together conform to an alkalic mineralising system.We propose a model for the development and evolution of the breccia pipes in conjunction with a model that describes the genesis of the porphyry Mo and auriferous breccia pipes as a unified magmatic-hydrothermal system,which is linked with transition from collisional compressional to extensional geodynamic regime. 相似文献