新疆孔雀河流域下游平原灌区土壤盐碱化改良的原则与治理措施研究

根据孔雀河流域下游平原灌区自然地理特征,分析盐碱地形成的原因,探讨实施治理盐碱地改良利用应遵守的原则,提出以水利土壤改良为先导,配以农艺改良和生物改良等治理综合措施。以期达到盐碱地标本兼治的目的,从而实现农业可持续发展。     

Temporal and spatial variability of dissolved organic carbon concentration in the Xijiang River, South China

A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological...     

喜马拉雅中东部镜像均衡重力异常的形成研究

青藏高原南缘处于重力不均衡状态,由北向南可依次分为高原近重力均衡区、喜马拉雅山正均衡异常区和山前盆地负均衡异常区,正、负异常呈现壮观的镜像分布。本文选取喜马拉雅中东部的均衡重力异常数据,结合地貌高程、地壳厚度、降雨量、冰川及山前沉积等的分布状况,探讨地貌分异与均衡重力异常分布的相互关系。由上述资料获得3条跨越喜马拉雅山的综合剖面,结果显示喜马拉雅中东部正均衡重力异常的分布与冰川、河流等代表的地表剥蚀作用存在明显的空间耦合关系,而与降雨量无直接联系,山前盆地负均衡重力异常与沉积厚度的分布也存在很好的耦合。利用数值模型计算得到了喜马拉雅地区的均衡调整时间域在1 Ma左右的时间尺度内。通过与地貌响应时间域相对比,以及对地表剥蚀厚度的估计,认为山脉地区的正均衡异常主要由地壳厚度补偿不足引起(侧重Airy假说),而山前盆地的负均衡异常主要由低密度沉积层的分布引起(侧重Pratt假说),由于地貌响应时间快于均衡调整时间,在大约5～2 Ma以来,地壳的均衡调整始终延迟于山脉的持续剥蚀和山前的持续沉积,使得岩石圈朝着"反均衡"方向演变,最终形成了喜马拉雅现今壮观的镜像均衡重力异常分布。     

The origin of the Maozu carbonate-hosted Pb–Zn deposit,southwest China: Constrained by C–O–S–Pb isotopic compositions and Sm–Nd isotopic age

The Maozu Pb–Zn deposit, located on the western margin of the Yangtze Block, southwest China, is a typical carbonate-hosted deposit in the Sichuan–Yunnan–Guizhou Pb–Zn metallogenic province with Pb + Zn reserves of about 2.0 million tonnes grading 4.15 wt.% Pb and 7.25 wt.% Zn. Its ore bodies are hosted in Sinian (635–541 Ma) Dengying Formation dolostone and show stratiform, vein and irregular textures. Ores are composed of sphalerite, galena, pyrite, calcite, dolomite, quartz and fluorite with massive, banded, disseminated and veined structures. The C–O–Sm–Nd isotopic compositions of hydrothermal calcites and S–Pb isotopic compositions of sulfides were analyzed to constrain the origin of the Maozu deposit. δ¹³C_PDB and δ¹⁸O_SMOW values of hydrothermal calcites range from −3.7‰ to −2.0‰ and +13.8‰ to +17.5‰, respectively, and plot near the marine carbonate rocks field in a plot of δ¹³C_PDB vs. δ¹⁸O_SMOW, with a negative correlation. It suggests that CO₂ in the hydrothermal fluids was mainly originated from marine carbonate rocks, with limited influence from sedimentary organic matter. δ³⁴S_CDT values of sulfides range from +9.9‰ to +19.2‰, similar to that of Cambrian to Triassic seawater sulfate (+15‰ to +35‰) and evaporate (+15‰ to +30‰) in the Cambrian to Triassic sedimentary strata. It suggests that reduced sulfur was derived from evaporate in sedimentary strata by thermo chemical sulfate reduction. Sulfides have low radiogenic Pb isotope compositions (²⁰⁶Pb/²⁰⁴Pb = 18.129–18.375, ²⁰⁷Pb/²⁰⁴Pb = 15.640–15.686 and ²⁰⁸Pb/²⁰⁴Pb = 38.220–38.577) that plot in the field between upper crust and the orogenic belt evolution curve in the plot of ²⁰⁷Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb, and similar to that of age corrected Proterozoic basement rocks (Dongchuan and Kunyang Groups). This indicates that ore-forming metals were mainly derived from basement rocks. Hydrothermal calcite yields a Sm–Nd isotopic age of 196 ± 13 Ma, possibly reflecting the timing of Pb–Zn mineralization in the SYG province, younger than the Permian Emeishan mantle plume (∼260 Ma). All data combined suggests that hydrothermal fluids circulated through basement rocks where they picked up metals and migrated to surface, mixed with reduced sulfur-bearing fluids and precipitated metals. Ore genesis of the Maozu deposit is different from known magmatic–hydrothermal, Sedimentary Exhalative or Mississippi Valley-types, which maybe represent a unique ore deposit type, named as the SYG-type.     

Kappa (k) derived from accelerograms recorded in the 2008 Wenchuan mainshock,Sichuan, China

High-frequency spectral decay factor, kappa (k), in the accelerograms of the Wenchuan mainshock was measured using strong motion data from 52 stations within 311 km of the epicenter. The derived k range from 0.0034 s to 0.0468 s. The correlation of k versus fault distance was given, which is k = 0.01288 + 5.9068 × 10^–5 R for the N-S component, k = 0.01881 + 1.4219 × 10^–5 R for the E-W component, and k = 0.00855 + 5.6086 × 10^–5 R for the U-D component. The analysis on the spatial variation of k demonstrates that k relates to source effect and propagation effect besides local site effect. Ground motions for the 52 stations were simulated using derived k and compared to actual recordings in terms of waveforms, amplitude spectra and response spectra. The results show agreement at shorter periods (<1 s), but a slight overestimation at longer periods (1–7 s).     

大别-苏鲁高压、超高压变质带榴辉岩和脉体中磷灰石氯含量和流体盐度关系的研究

流体的盐度对含羟基变质矿物组合的稳定温压条件和岩石-流体的相互作用有重要影响.流体的盐度可从矿物中氯含量的角度加以研究.磷灰石是一个含氯矿物,作为副矿物广泛分布在各种岩石中,且能在较宽的温压范围内稳定存在.本文选择大别-苏鲁造山带中典型的高压、超高压岩石开展了磷灰石成分的研究,结合前人流体包裹体的研究结果,探讨了榴辉岩相条件下流体盐度和磷灰石中的氯含量之间的关系.榴辉岩和脉体中磷灰石的XClAp/XOHAp比值与已有的流体包裹体盐度呈很好的线性正相关.榴辉岩和脉体中磷灰石的XClAp/XoHAp比值范围为0.00～0.35时,对应的流体包裹体盐度约为0～40％ NaCleqv.     

重庆市巫山县环湖路建设对淀粉厂滑坡影响的研究

重庆市巫山县环湖路地质条件十分复杂,沿线经过十几个地质灾害单元体。环湖路经过淀粉厂滑坡区时,以半挖半填的方式经过。环湖路建设对原滑坡体的稳定性影响进行重新评价计算,认为原设计方案不能满足要求,对原方案进行修改设计,完成淀粉厂滑坡的施工治理的环湖路的建设,实现了淀粉厂滑坡和环湖路工程建设的安全稳定。     

国家级强对流天气综合业务支撑体系建设

国家级强对流天气预报业务正在从以短期预报为主调整到短期和短时预报并重的业务格局。文章从强对流天气预报技术发展与服务需求的角度,重点介绍了国家级强对流天气综合业务支撑平台及其核心技术。该平台以气象数据组织和图形化表达两个核心要求为牵引,发展了数据分析处理系统、自动气象绘图系统和WEB检索与显示系统。数据分析处理系统基于多源观测资料、中尺度数值预报和全球数值预报,发展了集约、高效的强对流天气监测和临近预报、短时预报和短期预报等数据分析处理技术,是整个平台的核心;主要核心技术包括:从不稳定与能量、水汽、抬升与垂直风切变等条件出发,以归纳总结的分类强对流天气概念模型为基础的分类强对流短期预报分析技术;应用"配料法"发展的分类分等级的强对流天气客观概率预报技术;强对流短时预报技术包括高分辨率数值预报释用、多模式预报集成、对流尺度分析、实况和模式探空分析等多项技术,重点实现了从过去3 h实况到未来12 h预报的无缝隙衔接;强对流的监测和临近预报技术在基于多源资料的强对流天气实况与强对流系统监测技术基础上,发展了基于雷达特征量、强对流实况、各类强对流指数和预警信号等多源信息的报警技术。自动气象绘图系统实现了高效、便捷地接入多种数据、自动进行数据分析和制图等多项功能。在预报服务方面,基于WebGIS发展了县级分类强对流预警信号和国家级分类强对流预警预报产品共享技术,实现强对流短时预报业务的高交互性与上下互通的功能。     

多元均生函数模型及其在短期气候预测中的应用

在原均生数模型的基础上，对模型进行改进，首次引入预报因子变量，建立一个多元的均生函数模型。它适应于气温、降水、热带气旋个数等多种要素预报。新建的多元均生函数模型包含了原模型的优点。而且比原有均生函数模型具有更物理基础。     

我国南方初夏汛期和东亚夏季风环流

主要根据低层夏季风热力学性质与流场演变特点深入讨论我国南方初夏汛期包括华南前汛期和长江中下游梅雨期同夏季风活动的联系，分析了东亚夏季风环流建立过程的阶段性和类型，指出汛期的开始与结束同夏季风前沿位置变动一致。我国夏季风从开始到发展鼎盛时期低纬大气环流的演变过程各年不完全相同，主要可归纳为４类，每类包括４个或３个不同阶段，从而可认识到东亚夏季风体系结构的非单一性，它可有４种结构模型，即仅是东南季风Ｐ的单气流型、强东南季风Ｐ与弱西南季风Ａ的双气流型、强东南季风Ｐ和弱西南季风Ｍ的双气流型、强东南季风Ｐ和强（或弱）西南季风Ｍ以及弱西南季风Ａ的３气流型。