青海夏日哈木岩浆熔离型铜镍硫化物矿床1∶5万航磁异常特征及找矿意义

通过对夏日哈木铜镍矿床1∶5万航磁异常等地球物理特征的分析,该矿床在航磁异常上表现为弱磁异常,地磁异常上表现为中强磁异常,基性、超基性杂岩体具中等强度磁性,镍黄铁矿化、磁黄铁矿化等铜镍矿石具有以剩磁为主的较强磁性,铜镍矿体是引起磁异常的主要因素,磁异常是寻找该类矿床的直接标志之一。航磁异常对岩浆熔离型铜镍矿床的寻找具有重要意义,东昆仑地区多处航磁异常具有寻找岩浆熔离型铜镍矿的潜力。     

Tectonics and Sedimentary Basins of the South China Sea: Challenges and Progresses

The special issue "Tectonics and Sedimentary Basins of the South China Sea" consists of 19 articles arranged in the order of deep structure,general tectonics,tectonic modeling,and sedimentary basins especially the deepwater sedimentary basins.     

高效液相色谱-紫外光谱分析氢醌-双(β-羟乙基)醚

建立了高效液相色谱-紫外光谱法测定聚氨酯扩链剂氢醌-双(β-羟乙基)醚(HQEE)工业品中HQEE主含量和对苯二酚残留的方法。在氰基柱上,以甲醇-水-1%乙酸溶液(体积比10∶50∶40)为流动相,流速1.0 mL/min时,HQEE、对苯二酚及其他相关杂质得到良好分离,紫外光谱285 nm检测。方法简便、快捷,结果准确可靠,在工业生产中可有效地指导HQEE合成过程的质量控制。     

岩溶区土壤指纹电荷表征的土壤养分状况分析

以重庆金佛山岩溶区为例,分析不同石漠化程度下土壤的指纹电荷特征和土壤养分保持能力,结果表明:不同石漠化程度下,土壤指纹电荷特征变化明显,且呈衔接式-阶梯状发展,即:无石漠化阶段,土壤A、B层保持养分能力最强的pH范围与土壤实测pH较为吻合;轻度石漠化阶段,土壤A层养分保持能力受到明显扰动,而土壤B层养分保持能力与无石漠化的土壤A层较为一致;中、强度石漠化条件下,土壤A、B层保持养分能力的相对平衡点的pH值明显偏酸,这在A层表现尤为明显,主要为人为施肥的结果。并通过土壤有机质及其组分与土壤指纹电荷的相关分析,得出由于土壤富里酸有众多的活性功能团,它对土壤指纹电荷的作用明显大于胡敏酸。     

高密度电阻率法二维成像方法及其应用

高密度电阻率法在工程勘察和环境监测中是一种很重要的勘探手段，高密度电阻率法二维成像理论与方法的研究在理论和实际应用上都有着很重要的意义。随着地球物理反演和成像技术研究的兴起和发展，层析成像技术在高密度电阻率法中的应用，提高了高密度电阻率法的勘探质量和精度。本文献电阻率法层析成像技术的前提条件及高密度电阻率法二维成像理论与方法进行了粗浅探讨，最后给出了一些应用实例。     

重庆市岩溶区县土地利用景观破碎化及土壤侵蚀影响评价

根据重庆岩溶区县土地利用景观破碎情况,采用双向指示种分析法和除趋势典范对应分析法对研究区县及各土地利用类型进行分类和排序,揭示其空间分布的景观生态学意义及土壤侵蚀对土地利用景观破碎化的影响。根据分析结果, 可将研究区22种土地利用类型分为未利用地、平原耕地、山地耕地和灌草地4大类;可将研究区25个区县样方可分为低脆弱剧烈破碎区;低脆弱极强破碎区;低脆弱强破碎区;中脆弱中强破碎区;重脆弱中破碎区;重脆弱轻破碎区;中脆弱微破碎区7个样方群,空间上它们分属于渝东部、渝中部和渝西部3个区域,其土壤侵蚀性从东往西逐渐减弱。除趋势典范对应分析结果表明,较强的土壤侵蚀会加剧土地利用景观的破碎化,加剧破碎化的强度同土壤侵蚀等级呈现出相反的趋势。      

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time–energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.     

生态地球化学预测预警若干问题探讨

回顾了生态地球化学危害效应的作用机理,提出了区域地球化学调查-地球化学环境监测-机理研究相结合的生态地球化学预测预警基本思路。根据当前中国多目标区域地球化学调查和生态地球化学评价工作的现状,举例说明了土壤重金属元素累积、土壤环境变化、生态效应机理的若干研究方法,提出了预测预警成果体现的若干建议。     

晋县凹陷赵7井原油中异常高丰度地芰烷化合物 的检出及其稳定碳同位素组成

晋县凹陷赵7井原油中检出了异常高丰度的、具有5α,14β,17β(H)-立体构型(αββ-)的短链甾烷--地芰烷和甲基地芰烷.沉积环境是高丰富地芰烷和甲基地芰烷出现的重要影响因素.Requejo等报道的具有5β,14β,17α(H)立体构型(ββα-)的短链重排孕甾烷和重排升孕甾烷的出现,代表了过剩铁的沉积环境,研究区高丰度地芰烷和甲基地芰烷的出现,则代表了贫铁、硫过剩的沉积环境.     

Quantitative evaluation of the biostratigraphic distribution of acanthomorphic acritarchs in the Ediacaran Doushantuo Formation in the Yangtze Gorges area, South China

Doushantuo acanthomorphic acritarchs are large morphologically complex organic-walled microfossils broadly constrained between the 635 Ma Nantuo glaciation and the 551 Ma Miaohe Biota. They are potential biostratigraphic tools for subdivision and correlation of the Ediacaran System in South China. However, major variations in sedimentary facies and stratigraphic thickness present challenges in understanding the spatial and temporal distribution of these acritarchs. Further, the distribution of acritarchs in the Doushantuo Formation is associated with the presence of early diagenetic chert and phosphate, implying a certain degree of preservational bias and/or environmental control. The purpose of this paper is to document the stratigraphic distribution of Doushantuo acritarchs and to quantitatively evaluate their biostratigraphic significance and possible taphonomic–environmental biases, based on high-resolution paleontological data from six sections over 100 km in the Yangtze Gorges area, South China.A total of 1082 acritarch fossils were recorded from 84 chert horizons in the six sections of the study area. These chert horizons are not uniformly distributed throughout the Doushantuo Formation, thus the presence/absence of early diagenetic chert does play a role in controlling the distribution of acritarchs. The sampled chert horizons can be grouped into two stratigraphic intervals in the lower and upper Doushantuo Formation, respectively, based on regional stratigraphic correlation. Quantitative analysis shows that the two intervals are distinct taxonomically and largely independent of taphonomic or facies controls. Thus, the two intervals can be regarded as assemblage biozones. The lower biozone (biozone 1) is numerically dominated by Tianzhushania spinosa (n = 587; 68.3%) and Meghystrichosphaeridium magnificum (n = 74; 8.6%), whereas the upper biozone (biozone 2) is dominated by Ericiasphaera rigida (n = 104; 47.1%) and Tianzhushania spinosa (n = 34; 14.1%). The three most common genera, Meghystrichosphaeridium, Tianzhushania, and Ericiasphaera, have been identified in all sections. Correspondence analysis (CA), detrended correspondence analysis (DCA), discriminant analysis (DA), and pairwise comparisons of samples (Spearman rank coefficient and Jaccard–Chao index), all consistently support biostratigraphic zonations. Thus, the distribution of the Doushantuo acanthomorphs is primarily controlled by biostratigraphic position of samples, with facies and taphonomic differences playing a secondary role. Our case study suggests that acanthomorphic acritarchs can offer a viable tool for regional correlation of the Ediacaran System.