南天山西段巴雷公花岗岩体的地质年代学及锆石Hf同位素特征——岩石成因及对构造演化的约束

位于中国南天山增生造山带西段的巴雷公岩体的岩石类型为黑云母二长花岗岩。岩体中2件样品的LA-ICP-MS锆石U-Pb年龄为291±3 Ma和283±3 Ma。该岩体具有较高的SiO2(65.88%~72.99%)、K2O(4.23%~6.86%)和全碱含量(K2O+Na2O=7.45%~9.96%),呈现明显的Ba、Nb-Ta、Sr、P和Ti的负异常,以及轻稀土元素相对于重稀土元素的轻-中度富集和明显的Eu负异常(δEu=0.27~0.60)。上述这些特征与A型花岗岩一致。其锆石的εHf(t)值为-4.3~+1.7,二阶段Hf模式年龄为1.20~1.58 Ga。锆石Hf同位素和全岩地球化学特征暗示岩体起源于高温、低压条件下的下地壳中元古代角闪岩相变质基性火成岩的部分熔融。巴雷公岩体的围岩属于代表了南天山洋残迹的蛇绿混杂岩的一部分。巴雷公岩体无变形,侵入至蛇绿混杂岩单元中,具有"钉合岩体"的特点,从而为进一步限定洋盆闭合于二叠纪之前提供了证据。南天山增生造山带二叠纪岩体的Hf同位素均显示古老物源,揭示该增生造山带深部均为古老物质,是塔里木古老基底物质大量卷入的反映。     

红格铁矿三维反演与地质建模

四川红格钒钛磁铁矿是我国重要的岩浆岩型铁矿石产出基地。在过去几十年中,对红格地区进行了不同程度的勘探,积累了大量地质、物化探资料。但是,这些工作比较分散,不同单位不同时期用多种方法开展了多种比例尺的地质、物化探工作,资料零散的分布于不同单位,没有进行过系统的梳理及研究。本文对红格矿区进行有地质约束的三维磁异常反演,建立了三维地质模型,并实现了三维可视化。分析所建三维地质模型,从宏观上推测了红格铁矿的成矿控矿规律及岩浆运移通道,微观上预测了红格矿区矿体空间位置、形态及控矿、容矿、含矿地质体的分布规律。另外,结合地质模型还进行了找矿潜力评价,分析了矿区外围和深部的找矿前景。     

Spatiotemporal variation of meteorological droughts based on the daily comprehensive drought index in the Haihe River basin,China

Meteorological droughts can affect large areas and may have serious environmental, social and economic impacts. These impacts depend on the severity, duration, and spatial extent of the precipitation deficit and the socioeconomic vulnerability of the affected regions. This paper examines the spatiotemporal variation of meteorological droughts in the Haihe River basin. Meteorological droughts events were diagnosed using daily meteorological data from 44 stations by calculating a comprehensive drought index (CI) for the period 1961–2011. Based on the daily CI values of each station over the past 50 years, the drought processes at each station were confirmed, and the severity, duration and frequency of each meteorological drought event were computed and analyzed. The results suggest the following conclusions: (1) the use of the CI index can effectively trace the development of drought and can also identify the duration and severity of each drought event; (2) the average drought duration was 57–85 days in each region of the Haihe River basin, and the region with the highest average values of drought duration and drought severity was Bohai Bay; (3) drought occurred more than 48 times over the study period, which is more than 0.95 times per year over the 50 years studied. The average frequencies of non-drought days, severe drought days and extreme drought days over the study period were 51.2, 3.2 and 0.4 %, respectively. Severe drought events mainly occurred in the south branch of the Hai River, and extreme drought events mainly occurred in the Shandong Peninsula and Bohai Bay; (4) the annual precipitation and potential evapotranspiration of the Haihe River basin show decreasing trends over the past 50 years. The frequency of severe drought and extreme drought events has increased in the past 20 years than during the period 1961–1990. The results of this study may serve as a reference point for decision regarding basin water resources management, ecological recovery and drought hazard vulnerability analysis.     

双重含水介质水文地质参数的高分辨率识别

某火山岩矿区由于受后期构造影响,含水介质除了发育成岩裂隙-孔洞外,还发育有多组构造裂隙和剪切破碎带。抽水试验显示:抽水早期(≤6min)各观测孔的降深明显大于泰斯理论降深(单重均质),中后期(6min)趋于一致,呈现出双重含水介质的释水特征。本次研究在充分分析双重介质释水机理的基础上,结合时间步长为20s的高分辨率降深资料,采用分段泰斯模型进行了水文地质参数的识别。结果表明:剪切破碎带等强导水介质的弹性给水度略小于成岩裂隙-孔洞弱导水介质的弹性给水度;但导水系数相差很大,强导水介质一般为5 590~6 130m2/d,而弱导水介质仅715~743m2/d,这必然会导致未来矿山开拓过程中初见涌水量和稳定涌水量的显著差异,需要引起足够的重视。     

塔河油田于奇地区奥陶系碳酸盐岩岩溶作用研究

塔河油田北部于奇地区经多期构造运动,岩溶储层发育不均。从岩心观察、薄片鉴定、钻井和录井资料及测井、地震资料等方面进行分析解释,论述于奇地区奥陶系碳酸盐岩多期岩溶作用的存在依据和发育特征,总结同生、表生期大气水裸露风化壳型岩溶作用和侵蚀埋藏岩溶作用模式。结果表明:研究区西南部岩溶斜坡集中发育岩溶缝孔洞和洞穴,北部岩溶高地溶蚀作用不强,岩溶缝孔洞相对较少。于奇地区主要经历了加里东中晚期表生大气水岩溶作用、海西早期同生岩溶作用及海西期埋藏岩溶作用。     

Diamond Discovered in Dangqiong Ophiolite, Western Yarlung-Zangbu Suture Zone, Tibet

<正>The first diamonds from ophiolite were found in peridotite of Luobusa ophiolite along Yarlung Zangbu suture zone in Tibet,China(IGCAGS,1981),and then more and more diamonds found in harzgurgite(Bai et al.,1993;Yang et al.,2007a;Robinson et al.,2014;Xu et al.,     

我国城市规划中气候信息应用回顾与展望

城市规划中气候信息的应用经历了从早期的风玫瑰图利用到考虑风、温、湿、压等要素的气候适宜性分析以及目前关注城市通风环境、热环境以及污染敏感区的城市环境气候图技术的历程。气候信息获得的途径也从数量极为有限的基本气象观测站资料到空间加密的自动气象站资料、更精细的气象数值模式以及精细化地理信息技术的应用。同时,细化的技术导则和规范的建立以及不同行业间的联合发文有力推动了气候信息的实际应用。此外,研究展示了近年开展的伊犁、深圳、北京实际案例主要内容。最后,针对未来我国将根据大气环流特征和生态环境承载能力、走优化城镇空间布局和城镇规模结构的新型城镇化道路,从工作层面和技术层面给出了需要不断完善并深入研究的几个重点。     

晚中新世-上新世黄土高原佳县红粘土剖面碳同位素记录与C4植被演化

新生代C4植被开始扩张的年代、过程和驱动机制是全球古气候变化研究的焦点问题.中国黄土高原的黄土-红粘土剖面保存了连续的古生态演化记录,是研究这一关键科学问题的理想载体.本文选择黄土高原北部佳县厚达64m的红粘土剖面(8.2～2.7Ma),对190个层位的次生方解石矿物进行了无机碳同位素测试,由此分析了晚中新世-上新世末的C4植被扩张和演化过程.C4植被持续增长与全球冰盖的扩张基本一致,表明气候变冷很可能导致了黄土高原区域气候的干旱化与降雨季节性的增强.C4植被的扩张存在明显的3个阶段,分别以6.6Ma和3.6Ma为界限,每一次扩张增加10％左右,暗示了全球性的构造事件对黄土高原植被演化的控制.此外,佳县红粘土剖面呈现10次持续时间为10 ～ 20万年的碳同位素正漂移事件,平均每40万年发生一次,说明40万年轨道周期也控制着C4植被的演化.     

威德尔海的重磁场特征及其构造意义

威德尔海是南极洲最大的边缘海。通过搜集威德尔海的重磁资料、历史文献以及总结前人的相关研究成果,介绍了威德尔海的重磁场基本特征以及指示的构造意义。威德尔海最显著的重力特征是在威德尔海的中北部分布着以鲱骨式结构展布的一系列NW-SE向重力异常,其上可见一系列弧形、上凹的以E-W为主要方向的磁力异常。沿南极半岛陆架边缘的重力高一直可延伸到南侧海域,高值区与陆架平行,但是在磁异常上反映不明显。威德尔海原始海盆的形成约在150 Ma,并伴随南北向张裂,随后在140 Ma发生东西向扩张,到约120 Ma异常形成现代南极洲、非洲和南美洲板块的分布格局,鲱骨式结构异常脊也形成于该时期。     

Assessment of Constraint Factors of Resources and Environment of Sustainable Development in the Beijing-Tianjin-Hebeiregion: Based on the Framework of Landscape Sustainability Science

The Beijing-Tianjin-Hebei (BTH) region is an important engine for China’s socioeconomic development. Timely and effectively assessing constraint factors of resources and environment is of great significance for the sustainability assessment and the sustainable development of this region. However, comprehensive assessment research considering key resource and environmental constraints are still lacking. In this study, therefore, the limiting factors of resources and the environment in the BTH region were assessed based on the framework of landscape sustainability science. First, we chose five limiting factors, including topographic condition, geological environment, water resource, land resource, and atmospheric environment, to assess the constraints of resources and the environment using the single-factor evaluation method and the multi-factor comprehensive evaluation method. Based on the results, we divided the whole region into five subregions, i.e., the ecological conservation subregion, the geological disaster subregion, the water resource scarcity subregion, the atmospheric pollution subregion, and the cropland protection subregion. The results revealed that the northern BTH region was highly constrained by topographic conditions, the central BTH region was strongly constrained by geological environment and water resources, whereas the southern BTH region was constrained mainly by land resources and atmospheric environment. In addition, water resource was the main limiting factor for regional population growth and economic development. In 2010, the water resource scarcity subregion had a total population of 39.59 million, an urban population of 76.90%, and a gross domestic product of 2 455.57 billion yuan. We argue that the sustainable development of the BTH region should explicitly consider the resource and environmental limiting factors, implement land use optimization according to local conditions, maintain multiple land use types and diverse management strategies, based on the perspective of “strong sustainability”, so as to promote the regional sustainable development.