地壳内低速高导体在强震孕育过程中的作用的初步分析

在华北地区强震震源精细结构综合研究的基础上,利用理论分析方法,对华北地区强震震源区下方普遍存在的低速高导体,在强震孕育过程中的作用进行了探讨．结果表明,除了在孕震过程中低速高导体的存在有利于应力在其上覆脆性层内集中之外,在非弹性变形阶段,低速高导体对深部构造的活动具有促进作用．在孕震过程的后期,低速高导体可能对地震的发生具有触发作用．      

扫描电镜—能谱在单个包裹体物质组成研究中的应用

利用扫描电镜－能谱对四川冕宁稀土矿床早期萤石的单个流体－熔融包裹体的成分进行了分析,发现包裹体内流体相离子以Ｎａ、Ｃａ、Ｂａ为主,阴离子以ＳＯ４、Ｆ、Ｃｌ米,有意义的是在包裹体中发现了Ｌａ、Ｃｅ、Ｎｄ等稀土元素,其中矿化元素素铈的含量最高,研究结果进一步证明四川冕宁稀土矿床是一个与盐熔体有关的热液矿床。     

断陷盆地多次运移成藏的有机地球化学研究

油气运移一直是石油地质学中的重要理论问题, 也是该领域中的难题.以济阳拗陷东北部沾化凹陷中的几个油田为例, 根据原油及烃源岩有机地化分析结果, 特别是生物标志物的组成, 划分原油类型, 进行油源对比, 以探讨断陷盆地中油气多次运移和成藏的特征.研究证明: 沾化凹陷中渤南油田的形成与三次油气运移和成藏过程有关; 位于边缘断裂带的垦西油田是油气交替通过输导层作侧向运移和通过断层作纵向运移聚集的结果; 孤岛类型的古潜山油田的形成主要与油气从老第三纪油藏向上进行第三次运移有关.在断陷盆地内部以侧向运移和充注为主多形成单源油藏, 在断裂带以垂向充注为主常形成混源油藏.油气的多次运移与盆地中断裂活动的长期性和多期性有关.      

Water isotopes and hydrograph separation in different glacial catchments in the southeast margin of the Tibetan Plateau

Snow and glaciers are known to be important sources for freshwater; nevertheless, our understanding of the hydrological functioning of glacial catchments remains limited when compared with lower altitude catchments. In this study, a temperate glacial region located in the southeast margin of the Tibetan Plateau is selected to analyse the characteristics of δ¹⁸O and δD in different water sources and the contribution of glacier–snow meltwater to streamflow. The results indicate that the δ¹⁸O of river water ranges from ?16.2‰ to ?10.2‰ with a mean of ?14.1‰ and that the δD values range from ?117.0‰ to ?68.0‰ with a mean of ?103.1‰. These values are more negative than those of glacier–snow meltwater but less negative than those of precipitation. The d ‐excess values are found to decrease from meltwater to river to lake/reservoir water as a result of evaporation. On the basis of hydrograph separation, glacier–snow meltwater accounts for 51.5% of river water in the Baishui catchment in the melting season. In the Yanggong catchment, snow meltwater contributes 47.9% to river water in the premonsoon period, and glacier meltwater contributes only 6.8% in the monsoon period. The uncertainty in hydrograph separation is sensitive to the variation of tracer concentrations of streamflow components. The input of meltwater to a water system varies with local climate and glacier changes. The results confirm that hydrograph separation using water isotopes is valuable for evaluating the recharge sources of rivers, especially in ungauged glacial regions. This study provides insights into the hydrological processes of glacial catchments on the Tibetan Plateau, which is important for water resource management.     

河北省涞源县木吉村铜(钼)多金属矿田成矿物质来源探讨

木吉村铜(钼)矿田位于太行山脉中、北段阜平幔枝构造的北东倾伏端,涞源哑铃状杂岩体连接处西侧上盘拆离带的次级断陷盆地中,主要由斑岩型铜(钼)矿、矽卡岩型铁铜矿和外围热液脉型铅锌矿构成,是河北省目前探明的唯一大型铜(钼)多金属矿田,找矿远景巨大。鉴于矿床成矿物质来源在研究矿床成因和指导找矿中的重要作用,对木吉村矿田主要矿床矿石中黄铁矿、黄铜矿、方铅矿、辉钼矿、磁铁矿、石英和石膏等单矿物进行了硫、铅、碳、氢、氧、硅、铼等同位素测定、对比和分析。结果表明:矿田中硫同位素主值域δ34S=-3.5‰~3.2‰,主平均值为0.3‰;铅同位素206 Pb/204 Pb=15.566 0~17.072 0,平均为16.547 0,207Pb/204Pb=15.031 0~15.523 0,平均为15.258 0,208 Pb/204 Pb=36.292 0~37.375 0,平均为36.721 0;碳同位素δ13 C为-2.94‰~-2.18‰,平均为-2.62‰;硅同位素δ30 SiNBS-28值域为-0.3‰~0.2‰,平均0.0‰;辉钼矿w(Re)为(23.65~266.50)×10-6,平均值为142.33×10-6;δ18 OH2O值为-10.64‰~7.70‰,极差为18.34‰,平均值为-1.47‰,较标准岩浆水值稍低,δD值为-148.4‰~-89.0‰,极差为59.4‰,平均值为-113.7‰,略低于岩浆岩δD值域。从而认为,木吉村矿田成矿物质主要来源于地球深部,成矿溶液以岩浆水为主,部分来自大气降水。     

莫桑比克穆鲁普拉县穆卡拉地区土壤地球化学研究

通过在穆卡拉地区进行1:5万土壤地球化学测量,总结区内出露的地层、岩性、构造等地质特征,运用土壤地球化学方法进行找矿研究。元素地球化学参数统计显示,Zr、Bi、Au、Pb、Mo元素含量相对较高,变异系数较大,易参与次生富集作用,形成地球化学异常;元素分布型式显示,Ti、Ag、As、Co、Au、Cu、Bi、Mo分布广泛,离散度大,尤其是Cu元素呈显著的多峰分布,次生富集趋势强烈;因子分析、聚变分析多方统计分析表明,Cu、Ag、Au、As元素代表主要成矿元素的次生富集组合,可作为本区主要的找矿指示元素。     

生物肥部分替代化肥对甘蓝(Brassica oleracea)养分吸收、光合作用以及品质的影响

采用大田试验,研究了化肥减量20%~40%、配施生物肥对春茬甘蓝(Brassica oleracea)生长、养分吸收利用、光合作用以及品质的影响。结果表明:与当地施肥量(底肥:N 139.2kg·hm-2,P2O5255kg·hm-2,K2O 93.6kg·hm-2;追肥:N 208.8kg·hm-2)相比,化肥减量并配施生物肥使甘蓝生长前期、后期的茎粗变小;对甘蓝的叶片数、冠幅投影面积无显著影响;叶片的气孔导度、净光合速率均与对照无显著差异;促进了甘蓝叶球生长,叶球中硝酸盐和可溶性固形物含量降低,Vc含量增加;甘蓝叶球、叶片和根系氮含量降低,氮在叶球分配的比例提高,在叶片、根系分配的比例降低。化肥减量并配施生物肥提高了幼苗株高、增加了茎粗,气孔导度和净光合速率升高,降低了硝酸盐和可溶性固形物含量、叶球氮含量和根系的钾含量。     

Dynamic response of wind turbine towers in warm permafrost

Wind is a great source of renewable energy in western Alaska.Consistent winds blow across the barren tundra underlain by warm permafrost in the winter season,when the energy demand is the highest.Foundation engineering in warm permafrost has always been a challenge in wind energy development.Degrading warm permafrost poses engineering issues to design,construction,and operation of wind turbines.This paper describes the foundation design of a wind turbine built in western Alaska.It presents a system for response monitoring and load assessment,and data collected from September 2013 to March 2014.The dynamic properties are assessed based on the monitoring data,and seasonal changes in the dynamic properties of the turbine tower-foundation system and likely resonance between the spinning blades and the tower structure are discussed.These analyses of a wind turbine in warm permafrost are valuable for designing or retrofitting of foundations in warm permafrost.     

Advances in thermokarst lake research in permafrost regions

A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape developed during the process of permafrost degradation, we reviewed recent literature on thermokarst studies, and summarized the main study topics as： development and temporal evolution, carbon release, and ecological and engineering influence of thermokarst lakes. The climate warming, forest fires, surface water pooling, geotectonic fault and anthropogenic activity are the main influencing factors that cause an increase of ground temperatures and melting of ice-rich permafrost, resulting in thermokarst lake formation. Normally a thermokarst lake develops in 3–5 stages from initiation to permafrost recovery. Geo-rectified aerial photographs and remote sensing images show that thermokarst lakes have been mainly experiencing the process of shrinkage or disappearance in most regions of the Arctic, while both lake numbers and areas on the Qinghai-Tibet Plateau have increased. Field studies and modeling indicates that carbon release from thermokarst lakes can feedback significantly to global warming, thus enhancing our understanding of the influences of thermokarst lakes on the ecological environment, and on regional groundwater through drainage. Based on field monitoring and numerical simulations, infrastructure stability can be affected by thermal erosion of nearby thermokarst lakes. This review was undertaken to enhance our understanding of thermokarst lakes, and providing references for future comprehensive studies on thermokarst lakes.