青海湖沙柳河流域土壤水氢氧稳定同位素组成与土壤贮水量关系北大核心CSCD

氢氧稳定同位素技术和土壤贮水量是探究区域土壤水分特征的有效手段。基于青海湖沙柳河流域土壤水氢氧稳定同位素组成(δ2H和δ^(18)O)和土壤贮水量数据,分析其在流域的空间分布特征,探讨土壤水氢氧稳定同位素组成和土壤贮水量之间的相关性。结果表明:(1)沙柳河流域土壤水δ^(18)O值从西北向东南呈现富集—贫化—富集的趋势;土壤水d-excess值在流域南部最低,在流域东北部支流上游地区最高。(2)土壤贮水量在流域空间分布上表现为北高南低的趋势。(3)土壤水δ^(18)O值、d-excess值与土壤贮水量间存在分段线性关系。当0—30 cm各土层土壤贮水量≤30 mm时,各土层土壤贮水量与土壤水δ^(18)O值分别显著负相关、与d-excess值显著正相关。青海湖沙柳河流域自然地理环境和植被特征的空间差异导致其土壤水氢氧稳定同位素组成和土壤贮水量表现出明显的空间变异性。温度变化对土壤水氢氧稳定同位素组成与土壤贮水量之间的相关性影响是通过其对土壤蒸发作用的影响来实现的。     

山西长治南部经坊煤矿奥陶系峰峰组水文地质条件分析

经坊煤矿目前开采的山西组3号煤层逐步枯竭,矿井设计开采太原组8、9、14、15号煤层。奥陶系峰峰组是太原组煤层底板的间接充水含水层。以往大多数勘查成果得出该地区峰峰组岩溶裂隙发育较差,富水性弱-中等的结论,以至于个别矿井在奥灰带压开采危险性评价时甚至将其视为相对隔水层。因此,查明峰峰组的水文地质特征是太原组煤层能否实现安全带压开采的关键。通过岩心采取、抽水试验和水化学分析等多种手段的勘查认为:该地区峰峰组富水性普遍较强,处于主径流带附近富水性极强。该研究对于长治南部地区供水勘查和太原组煤层安全带压开采具有重要的指导意义。     

http://www.sciencedirect.com/science/article/pii/S1674987113000364

The South Tianshan Orogen and adjacent regions of Central Asia are located in the southwestern part of the Central Asian Orogenic Belt.The formation of South Tianshan Orogen was a diachronous,scissors-like process,which took place during the Palaeozoic,and its western segment was accepted as a site of the fnal collision between the Tarim Craton and the North Asian continent,which occurred in the late Palaeozoic.However,the post-collisional tectonic evolution of the South Tianshan Orogen and adjacent regions remains debatable.Based on previous studies and recent geochronogical data,we suggest that the fnal collision between the Tarim Craton and the North Asian continent occurred during the late Carboniferous.Therefore,the Permian was a period of intracontinental environment in the southern Tianshan and adjacent regions.We propose that an earlier,small-scale intraplate orogenic stage occurred in late Permian to Triassic time,which was the frst intraplate process in the South Tianshan Orogen and adjacent regions.The later largescale and well-known Neogene to Quaternary intraplate orogeny was induced by the collision between the India subcontinent and the Eurasian plate.The paper presents a new evolutionary model for the South Tianshan Orogen and adjacent regions,which includes seven stages:(I)late Ordovicianeearly Silurian opening of the South Tianshan Ocean;(II)middle Silurianemiddle Devonian subduction of the South Tianshan Ocean beneath an active margin of the North Asian continent;(III)late Devonianelate Carboniferous closure of the South Tianshan Ocean and collision between the Kazakhstan-Yili and Tarim continental blocks;(IV)early Permian post-collisional magmatism and rifting;(V)late PermianeTriassic the frst intraplate orogeny;(VI)JurassicePalaeogene tectonic stagnation and(VII)NeoceneeQuaternary intraplate orogeny.     

Simulation of CO2 plume movement in multilayered saline formations through multilayer injection technology in the Ordos Basin,China

Deep saline aquifers still remain a significant option for the disposal of large amounts of CO₂ from the atmosphere as a means of mitigating global climate change. The small scale Carbon Capture and Sequestration demonstration project in Ordos Basin, China, operated by the Shenhua Group, is the only one of its kind in Asia, to put the multilayer injection technology into practice. This paper aims at studying the influence of temperature, injection rate and horizontal boundary effects on CO₂ plume transport in saline formation layers at different depths and thicknesses, focusing on the variations in CO₂ gas saturation and mass fraction of dissolved CO₂ in the formation of brine in the plume’s radial three-dimensional field around the injection point, and interlayer communication between the aquifer and its confining beds of relatively lower permeability. The study uses the ECO2N module of TOUGH2 to simulate flow and pressure configurations in response to small-scale CO₂ injection into multilayer saline aquifers. The modelling domain involves a complex multilayer reservoir–caprock system, comprising of a sequence of sandstone aquifers and sealing units of mudstone and siltstone layers extending from the Permian Shanxi to the Upper Triassic Liujiagou formation systems in the Ordos Basin. Simulation results indicate that CO₂ injected for storage into deep saline aquifers cause a significant pressure perturbation in the geological system that may require a long duration in the post-injection period to establish new pressure equilibrium. The multilayer simultaneous injection scheme exhibits mutual interference with the intervening sealing layers, especially when the injection layers are very close to each other and the corresponding sealing layers are thin. The study further reveals that injection rate and temperature are the most significant factors for determining the lateral and vertical extent that the CO₂ plume reaches and which phase and amount will exist at a particular time during and after the injection. In general, a large number of factors may influence the CO₂–water fluid flow system considering the complexity in the real geologic sequence and structural configurations. Therefore, optimization of a CO₂ injection scheme still requires pursuance of further studies.     

Dynamics of willow tree (Salix matsudana) water use and its response to environmental factors in the semi-arid Hailiutu River catchment,Northwest China

Sap flow (SF)of a willow tree, meteorological variables, soil water content, and water table depth were measured during the growing period from mid-April to October, 2011 in the semi-arid Hailiutu River catchment, Northwest China. The measurements of SF showed diurnal fluctuations in sunny days and seasonal changes from 1.65 l/h in mid-April to 33 l/h in July. At hourly scale, SF is significantly correlated with net radiation, followed by air temperature, relative humidity, and wind speed. At daily scale, air temperature affects the dynamics of SF significantly. Daily SF correlates positively with net radiation and negatively with relative humidity. There is no correlation observed between daily SF and wind speed. The measurements of SF do not indicate water stress although the experimental period is dry. Correlation analysis shows that SF is strongly correlated with soil moisture and water table depth, indicating the willow tree uses both soil water and groundwater for transpiration.     

龙门山冲断隆升及其走向差异的裂变径迹证据

大量的低温年代学研究用来讨论龙门山晚新生代的隆升,但很少涉及其走向差异和中生代隆升。本文分别沿龙门山北、中、南段3条剖面进行了锆石和磷灰石裂变径迹测试,结合已有的热年代学数据,以期揭示整个中-新生代期间龙门山隆升历史及其时空变化。中生代以来,龙门山主要有印支期(约200 Ma)、早白垩世末(约100 Ma)、早新生代(65～30 Ma)以及晚中新世(15～9 Ma)等或快或慢的冷却事件,总体上经历了中生代至早新生代的缓慢冷却和晚新生代快速冷却2个阶段,快速剥露开始于15～9 Ma,剥蚀速率由早期的0.1 mm/a增加到0.15～0.3 mm/a左右,局部可达0.9 mm/a左右。走向上,龙门山北段相对偏小的锆石裂变径迹年龄和相对偏大的磷灰石裂变径迹年龄反映其在中生代较中、南段隆升更快,而裂变径迹年龄总体上从北段向中、南段减小,表明中、南段在新生代发生了更快的隆升。倾向上,多种热年代学数据显示新生代期间在北川断裂和彭灌断裂两侧存在明显的差异剥露,这种差异在中、南段表现比北段更为突出。龙门山晚新生代快速隆升和剥露是青藏高原区域隆升背景上叠加的冲断活动所致,而非下地壳流动驱动。     

安徽宁芜地区铁氧化物-磷灰石矿床中金云母Ar-Ar定年及其地球动力学意义

铁氧化物-磷灰石型铁矿床是长江中下游成矿带的重要组成部分,对其成岩成矿时限的精确厘定,是理解长江中下游地区中生代大规模成矿作用的动力学演化的关键。本文分别对宁芜盆地南部白象山、和睦山及中部的陶村三个大-中型铁矿床中与磁铁矿密切共生的金云母单矿物进行了Ar-Ar同位素测年,获得白象山矿床金云母Ar-Ar坪年龄为134.9±1.1Ma,对应的反等时线年龄为133±2Ma;和睦山矿床金云母Ar-Ar坪年龄为132.9±1.1Ma,对应的反等时线年龄为133.9±2.4Ma;陶村矿床金云母的反等时线年龄为128±14Ma。该区铁氧化物-磷灰石型矿床与该区火山-次火山岩具有密切的时间联系,成岩成矿时限主要集中于135～126Ma。综合研究表明,长江中下游第二期成岩成矿作用的时限为135～126Ma,对应于岩石圈的大规模快速减薄的地球动力学背景。     

碳酸盐岩中锶元素地球化学特征及其指示意义

应用锶指示古环境的方法很多,其中以锶的含量和与Sr配对的相应的元素比值作为指示剂,具有典型代表性。本文以北京下古生界碳酸盐岩为研究对象,采用ICP-MS分析技术测试了49件样品中Sr、Ba、Cu的含量。以锶的含量、Sr/Ba、Sr/Cu比值作为地化指标,深入探讨了锶的地球化学特征。系统的分析了Sr含量,Sr/Ba、Sr/Cu比值对不同的沉积环境的地质响应。指出从浅海环境到深海环境Sr含量及其相应的元素比值增加趋势明显,对沉积环境具有重要的指示作用。并且,Sr的分布还受到不同沉积旋回的影响,研究沉积作用对Sr分布的影响时,应在同一沉积旋回中进行。此外还深入研究了不同岩性、不同沉积旋回中Sr的分布特征,探讨了影响Sr分布的不同因素。归纳了锶对沉积环境的指示作用。就成岩作用对碳酸盐岩中锶分布的影响,结合前人的工作,进行了探索性的分析。     

渝南—黔北奥陶系五峰组的同生变形构造及其地质意义

重庆綦江奥陶系五峰组中—下部的黑色页岩中发育有一系列主要由阶梯状断层和其间的小型褶皱构成的同生变形构造(contemporaneous deformed structures),并可大致分为3个构造层段。沉积后—固结成岩前所形成的同生变形构造层之上为正常沉积的黑色页岩层。另外,在贵州桐梓五峰组距底部2.3m左右的黑色页岩中也发育有与綦江地区相似的、以小型褶皱为主的同生变形构造层,且此同生变形构造层上下为斑脱岩层。同生变形构造的发现,表明渝南—黔北地区奥陶纪晚期(五峰期)的沉积盆地为非平坦的古地貌,且曾发生过多期可能与火山运动相关的构造运动。     

On quasi-periodic motions around the triangular libration points of the real Earth–Moon system

The two triangular libration points of the real Earth–Moon system are not equilibrium points anymore. Under the assumption that the motion of the Moon is quasi-periodic, one special quasi-periodic orbit exists as dynamical substitute for each point. The way to compute the dynamical substitute was discussed before, and a planar approximation was obtained. In this paper, the problem is revisited. The three-dimensional approximation of the dynamical substitute is obtained in a different way. The linearized central flow around it is described.