甘肃祁连山西段金矿分布特征及控矿因素分析

祁连西段是甘肃省重要的金成矿带,分布有鹰嘴山、寒山、阳凹大泉、车路沟、金湾子等金矿床,近年又新发现豹子沟南、滴水山、牛毛泉、积阴功台金矿,显示出较大的区域找矿潜力。本文通过典型金矿床和新发现金矿成矿地质条件分析,总结了甘肃祁连山西段金矿的空间分布特征、控矿因素。初步研究认为祁连山西段主要的金矿床呈带状分布于阿尔金走滑断裂与北祁连褶皱断裂构造带交汇部位,明显受不同规模、不同序次的韧、脆性断裂构造破碎带控制;成矿与区域内不同规模中酸性—中基性岩体及岩脉有关;古生代火山碎屑岩、浅变质碎屑岩为主要容矿岩性及含矿建造;矿体普遍具有延深大于延长、深部明显富集的特征。新发现金矿多以化探异常查证为重点,不断浓缩异常源,实现找矿突破。本文对祁连山西段的金矿勘查具有指导意义,对该地区的金矿研究也提供了重要的基础资料。     

IPCC AR6报告解读：未来的全球气候——基于情景的预估和近期信息

依据IPCC第六次评估报告（AR6）第一工作组报告第四章的内容,对未来全球气候的预估结果进行解读。报告对21世纪全球表面气温、降水、大尺度环流和变率模态、冰冻圈和海洋圈的可能变化进行了系统评估,并对2100年以后的气候变化做了合理估计。评估指出全球平均表面气温将在未来20年内达到或超过1.5℃,平均降水也将增加,但随季节和区域而异,同时变率将增大。大尺度环流和变率模态受内部变率影响较大。到21世纪末,北冰洋可能出现无冰期;全球海洋会继续酸化,平均海平面将持续上升,百年内上升幅度依赖不同排放情景,都在2100年后继续升高。在最新的评估中采用多种约束方法,减小了预估不确定性的范围。AR6对于低排放情景以及“小概率高增暖情节”的关注为应对气候变化提供了更多、更完整的信息。综合报告的评估结果指出,未来需要进一步减小区域,特别是季风区气候预估的不确定性,并从科学研究和模式发展两方面加强我国气候预估能力的建设。     

Performance of GPS and GPS/SINS navigation in the CE-5T1 skip re-entry mission

A CE-5T1 spacecraft completed a high-speed skip re-entry to the earth after a circumlunar flight on October 31, 2014. In addition to the strapdown inertial navigation system (SINS), a lightweight GPS receiver with rapid acquisition was developed as a navigation sensor in the re-entry capsule. The GPS receiver effectively solved the poor accuracy problem of long-term navigation using only the SINS. In contrast to ground users and low-earth-orbit spacecraft, numerous factors, including high altitude and kinetic characteristics in high-speed skip re-entry, are important for GPS positioning feasibility and were presented in accordance with the flight data. GPS solutions started at nearly 4900 km orbital altitude during the phases of re-entry process. These solutions were combined by an inertial measurement unit in a loosely coupled integrated navigation method and SINS navigation initialization. A simplified GPS/SINS navigation filter for limited resources was effectively developed and implemented on board for spacecraft application. Flight data estimation analyses, including trajectory, attitude, position distribution of GPS satellite, and navigation accuracy, were presented. The estimated accuracy of position was better than 42 m, and the accuracy of velocity was better than 0.1 m/s.     

论中国国家公园地质考察与评价——以浙江丽水百山祖国家公园为例

鉴于保护地调查评价历史与目标,国家公园地质考察评价基准是地质学关于地球的“时间、空间、演化”知识的发现路径,既识别国家公园候选地的国家符合性地质事件,又识别国家公园自然性、独特性、优美性、多样性、整体性的地质机制,提供国家公园最重要的自然生态系统与自然景观保育管理的地质学支撑。浙江丽水百山祖国家公园符合性的地质事件是公园发现的4.0~4.2 Ga冥古宙陆核物质的锆石晶体、中生代岛弧陆盆火山酸性火山岩系列和从流纹岩山岭到花岗岩—变质岩谷底的“峰—岭—丘—谷（盆）”的亚热带滨海山地地貌结构,地貌结构发育演化是百山祖公园最重要的自然生态系统、区域性流域水源地、独特山水景观的形成基础。保护百祖山公园地貌结构和过程的完整性与真实性是确保其重要自然生态系统自然演化和生态服务产品持续供给的基础。     

Social media information sharing for natural disaster response

Natural Hazards - Prediction in ungauged basins (PUB) is as crucial as it is challenging. Thus far, there have been abundant regionalization studies on PUB, whereas "regionalization" is...     

Application of generalized Pareto distribution for modeling aleatory variability of ground motion

Natural Hazards - The lognormal distribution is commonly used to characterize the aleatory variability of ground-motion prediction equations (GMPEs) in probabilistic seismic hazard analysis (PSHA)....     

陇中盆地及周边地区主夷平面演化与高原隆升

陇中盆地及周边地区是青藏高原向北东方向扩展的最前缘部位,其地貌演化过程的研究对于深入理解高原的隆升与扩展过程具有重要意义。鉴于夷平面在探讨高原隆升年代、幅度和过程方面的可靠性,首先总结陇中盆地及周边地区夷平面相关研究的前期成果,并结合最新年代数据,确定了不同区域主夷平面的发育和解体年代;再利用古河道拟合等方法定量评估了相关夷平面的隆升量;最后探讨了主夷平面的性质及其隆升过程。研究发现,陇中盆地及周边的地区的高海拔低起伏地貌面是被抬高的先存夷平面;不同区域主夷平面的发育与解体时间整体同步,它们自晚渐新世开始发育,并于晚中新世8~6 Ma左右解体;模拟结果表明,美武高原主夷平面自晚中新世以来相对陇中盆地隆升了约1 400~1 600 m,并且早更新世以来的隆升速率明显大于晚中新世-早更新世时期。     

华北克拉通南缘古元古代晚期汝阳群微体化石及其古环境意义:来自微细构造和生物标志化合物的证据

华北克拉通南缘古元古代晚期汝阳群白草坪组页岩中产出大量的具刺和细网状纹饰的球形疑源类,其中以Shuiyousphaeridium macroreticulatum与Dictyosphaera macroreticulata化石标本最具代表性.利用扫描电子显微镜结合光学生物显微镜对其膜壳微细构造进行观察,结果显示:膜壳表面的刺饰形态具有多样性分叉;其膜壳壁可能是由多边形网脊及膜层构成,而不是由多角形板片及膜层构成.同时通过对比研究,认为两种最具代表性的特征分子可能是同一生物不同阶段的产物.此外,通过对赋存微体化石页岩进行生物标志化合物分析,检测到的姥鲛烷/植烷比(Pr/Ph)大于1、伽马蜡烷丰度中等及生物标志化合物(C₃₀藿烷、C₂₇甾烷和三环萜烷),结合前人关于汝阳群沉积环境的研究,不仅指示了汝阳群微体化石群沉积古环境应为正常的海洋环境——滨海-浅海相,也指示了元古代真核生物已经存在,为重建微体化石群和探讨早期生命演化提供了重要的理论依据.      

Effect of the Dry Ashing Method on Cadmium Isotope Measurements in Soil and Plant Samples

A dry ashing method is commonly used to remove organic material from samples prior to geochemical analysis. In the course of this study, the Cd isotope ratios of a series of soil and plant reference materials and samples were studied to evaluate the effect of the dry ashing method on measurement results of Cd isotope ratios. The samples were pre‐treated using the dry ashing method and high‐pressure bomb for comparison. The results show that the digestion using high‐pressure bombs did not lead to Cd loss, but using the dry ashing method would cause different proportions of Cd loss. The whole range of Cd isotope difference between two methods was from ?0.07‰ to 3.01‰. There was also an obvious difference in measured Cd isotope ratios from the same leaf sample pre‐treated independently by the dry ashing method, indicating that the amount of Cd loss and the effect on Cd isotope measurement during dry ashing is related to the properties of the samples. Therefore, dry ashing may not be appropriate for the removal of organic material in Cd isotope ratio measurement, especially for samples with high organic contents. The δ^114/110Cd values of reference materials NIST SRM 1573a and GSD‐30 are reported for the first time in this study.