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21.
断裂密度衍是引自吉尔吉斯斯坦的一种测震学地震预报新方法,用以探索大震之前某一区域或地段面断裂密度的异常变化。应用该方法对新疆天山部分地区进行系统研究后,根据研究结果制定出了具有一定信度的定量或半定量预报指标。 相似文献
22.
大兴安岭南段赛罕乌拉石海剖面分析及其与蒙山拦马墙石河结构对比 总被引:1,自引:0,他引:1
石海(石河/冰石河)作为冰缘地貌的重要标志之一,在国内地学界尚未引起足够的重视,以至于缺少介绍石海结构特征的中文文献,更未建立判别标准,在地貌认知阶段就发生很多误判。为了揭示石海的剖面结构特征,笔者等对位于大兴安岭南段的赛罕乌拉国家级自然保护区乌兰坝石海首次进行了开挖解剖,从而归纳了原生石海的基本结构特征:岩块棱角鲜明,呈镂空状堆积,岩块直径总体上上大下小。根据野外调查确认,赛罕乌拉海拔1800 m以上的区域至少还存在着局部现代石海,也就是说,还残存着不连续冻土带,而且保持年平均气温0℃左右的气候环境。根据赛罕乌拉现今气候记录和石海分布,笔者等估算了全新世初期赛罕乌拉石海开始发育时的地表温度在0~-4℃,而今天年平均气温已经升高到2℃,升温幅度2~6℃。根据赛罕乌拉石海剖面结构特征,笔者等对山东蒙山石河进行了结构对比,认为二者剖面结构基本一致,排除了前人近年来争议明显的冰川侧碛堤和泥石流成因说。结构对比揭示山东蒙山境内全新世早期至少局部存在过冰缘气候环境,而这也为山东境内更新世冰川地貌研究提供了重要的信息。此外,本研究也为中国冰缘地貌解剖和资源调查提供了一个可以参考的研究实例。 相似文献
23.
Rare earth elements (REE) of dissolved and suspended loads in the Xijiang River, South China 总被引:4,自引:0,他引:4
The Xijiang River is the main channel of the Zhujiang (Pearl River), the second largest river in China in terms of water discharge, and flows through one of the largest carbonate provinces in the world. The rare earth element (REE) concentrations of the dissolved load and the suspended particulate matter (SPM) load were measured in the Xijiang River system during the high-flow season. The low dissolved REE concentration in the Xijiang River is attributed to the interaction of high pH and low DOC concentration. The PAAS-normalized REE patterns for the dissolved load show some common features: negative Ce anomaly, progressively heavy REE (HREE) enrichment relative to light REE (LREE). Similar to the world’s major rivers the absolute concentration of the dissolved REE in the Xijiang River are mainly pH controlled. The degree of REE partitioning between the dissolved load and SPM load is also strongly pH dependent. The negative Ce anomaly is progressively developed with increasing pH, being consistent with the oxidation of Ce (III) to Ce (IV) in the alkaline river waters, and the lack of Ce anomalies in several DOC-rich waters is presumably due to both Ce (III) and Ce (IV) being strongly bound by organic matter. The PAAS-normalized REE patterns for the dissolved load and the SPM load in rivers draining the carbonate rock area exhibit middle REE (MREE) enrichment and a distinct maximum at Eu, indicating the preferential dissolution of phosphatic minerals during weathering of host lithologies. Compared to the Xijiang River waters, the MREE enrichment with a maximum at Eu disappeared and light REE were more depleted in the South China Sea (SCS) waters, suggesting that the REE sourced from the Xijiang River must be further fractionated and modified on entering the SCS. The river fluxes of individual dissolved REE introduced by the Xijiang River into the SCS vary from 0.04 to 4.36 × 104 mol a−1. 相似文献
24.
以西汉、东汉、唐朝三个历史时期为研究时间域,以新疆境内的古丝绸之路为研究空间域;根据搜集的相关历史文献资料并对其进行分析,将得到的西域三十六国域址、人口、军事等信息存入MySQL数据库中;结合地理信息系统(GIS)及遥感(RS)技术,将传统的纸质地图转变成电子地图并发布相应的本地地图服务;最后,利用PHP及Flex网络技术,将前期制作的电子地图发布到Internet上,供公众浏览、查询、学习交流等之用。本研究将传统的考古学与现代信息技术进行结合,实现了两者的完美融合,弥补了传统考古学过于专注学术研究而忽略应用的缺陷,为公众免费提供服务的同时,也为丝绸之路的进一步研究提供参考资料,同时为丝绸之路的申遗工作奠定基础。 相似文献
25.
Xiaolong Liu Siliang Li Zhongliang Wang Guilin Han Jun Li Baoli Wang Fushun Wang Li Bai 《中国地球化学学报》2017,36(4):667-679
Aquatic ecosystems have been identified as a globally significant source of nitrous oxide (N2O) due to continuous active nitrogen involvement, but the processes and influencing factors that control N2O production are still poorly understood, especially in reservoirs. For that, monthly N2O variations were monitored in Dongfeng reservoir (DFR) with a mesotrophic condition. The dissolved N2O concentration in DFR displayed a distinct spatial–temporal pattern but lower than that in the eutrophic reservoirs. During the whole sampling year, N2O saturation ranging from 144% to 640%, indicating that reservoir acted as source of atmospheric N2O. N2O production is induced by the introduction of nitrogen (NO3 ?, NH4 +) in mesotrophic reservoirs, and is also affected by oxygen level and water temperature. Nitrification was the predominate process for N2O production in DFR due to well-oxygenated longitudinal water layers. Mean values of estimated N2O flux from the air–water interface averaged 0.19 µmol m?2 h?1 with a range of 0.01–0.61 µmol m?2 h?1. DFR exhibited less N2O emission flux than that reported in a nearby eutrophic reservoir, but still acted as a moderate N2O source compared with other reservoirs and lakes worldwide. Annual emissions from the water–air interface of DFR were estimated to be 0.32 × 105 mol N–N2O, while N2O degassing from releasing water behind the dam during power generation was nearly five times greater. Hence, N2O degassing behind the dam should be taken into account for estimation of N2O emissions from artificial reservoirs, an omission that historically has probably resulted in underestimates. IPCC methodology should consider more specifically N2O emission estimation in aquatic ecosystems, especially in reservoirs, the default EF5 model will lead to an overestimation. 相似文献
26.
杨家堡子铁矿位于山东省枣庄市峄城区峨山镇,隶属苍峄铁成矿带,矿体赋存于新太古代泰山岩群山草峪组上部的变质岩中。该矿床内圈定磁铁矿体11个,求得铁矿石(333)资源量3 378.2万t,矿床平均品位TFe 33.30%,mFe 22.64%。主矿体为Ⅲ-6矿体,占矿床总资源量的83.69%,其长度1 137 m,最大斜深1 065 m,埋深707~1 369m,形态复杂程度中等,品位变化属均匀类型。含矿岩石为磁铁石英角闪岩。矿石中的主要有用组分为Fe,伴生元素含量较低,均无综合回收利用价值,有害组分S、P的含量均较低,经选矿后可达到炼钢及炼铁要求。矿石结构主要有粒状变晶结构和柱状变晶结构;矿石的构造主要为条带状构造,块状构造的矿石较少,但品位相对较高。矿石自然类型为原生磁铁矿石,工业类型属需选磁性铁矿石。该矿床成因与苍峄铁矿一脉相承,为典型的BIF型铁矿。根据区内以及邻区的见矿情况结合磁异常特征分析,杨家堡子矿区有良好的找矿前景。 相似文献
27.
28.
GENG Wenhui YAO JinyanGuilin Research Institute of Geology for Mineral Resources Fuxing R Guilin Guangxi 《《地质学报》英文版》2000,74(3):511-515
The metallogenesis of subvolcanic deposits is controlled by subvolcanic activities. The copper polymetallic deposits are genetically related to intermediate-acid rocks, and the silver polymetallic deposits are more closely related to acid rocks. The abundance of Cu is relatively high in the intermediate-acid rocks and subvolcanic rocks, whereas the abundances of Pb, An and Ag are high in acid rocks, indicating rich ore-forming elements in original magmas. The study of REEs shows that the magmatic type related to copper deposits is the syntectic type, and that related to silver polymetallic deposits is mainly the re-melting type. The deposits were formed under medium-low temperatures and low salinity. The metallogenic times were the late stage of the early Yanshanian or the late Yanshanian, dating 78-147 Ma. 相似文献
29.
准噶尔盆地腹部地区侏罗系地层超压普遍发育,超压层段与声波时差、电阻率两者之间具有较好的响应关系,尤以电阻率响应最为显著,超压层段声波时差表现为异常高值,电阻率为异常低值的特征。利用准噶尔盆地腹部地区大量测井、测试及相关地质资料综合论述超压成因,指出泥岩和砂岩中发育的超压并非由压实不均衡、构造挤压等作用导致,而主要由生烃作用造成的。研究表明有以下几方面主要证据:1)超压泥岩密度不具有异常低值特征;2)超压段泥岩密度与岩石颗粒垂直有效应力之间不存在线性关系;3)超压砂岩不存在异常高地温梯度现象;4)超压顶界面深度范围为3 800~4 300 m,侏罗系烃源岩现今成熟度(Ro%)范围为0.6%~0.9%,温度范围分布在90 ℃~125 ℃;5)超压层段的侏罗系烃源岩现今生烃转化率最高可达70%,现今平均生油率可达90 mg/g·TOC,仍具有较强的生烃能力;6)泥质烃源岩本身对超压具有很好的封闭作用;7)侏罗系烃源岩内发育大量低角度或高角度微裂缝;8)超压储层主要以油层为主,无水层,准噶尔盆地东道海子北凹陷砂岩中超压主要是通过烃源岩中排出的高压流体运移至储层发生超压传递的结果。 相似文献
30.