区域重力异常高精度实现异常转换的一个普遍方法

应用Ⅲпемнпъх级数展开不同类型异常转换的频率特征,可以得到空间域级数求和法进行异常转换的诸系数.对延拓距分别为取数点距0.3, 0.5, 0.7, 1.0, 1.3, 1.5, 2.0倍的向下延拓、向上延拓、一阶垂向导数、二阶垂向导数的异常转换,求出了级数求和法的诸系数.从而实现了在原重力异常上一次等距取点求得各种不同的转换异常.通过模型理论计算值和利用上述方法算出的不同高度的延拓值进行对比,发现本法精度较高,可应用于区域重力异常的异常转换中,从而拓宽了重力转换异常的应用.     

海温异常特征与台湾“9.21”地震

本文介绍海温与台湾地区 7级地震的关系 ,表明海温异常具有预报意义。同时着重分析了 1 999年 9月 2 1日台湾地震前的海温异常特征。本人据此在 1 998年的年度会商中提出了预报意见。     

电磁辐射对台湾强震的反应

本文通过对 1 999年 9月 2 1日台湾南投 7 6级强震前电磁辐射变化特征的分析 ,进一步探讨了电磁辐射在短临预报中的作用 ,同时给出了初步判断震中位置的方法     

小西南岔—杨金沟地区综合找矿信息研究

本文研究了小西南岔-杨金沟地区的火山岩建造、侵入岩建造、沉积岩建造的建造特征;探讨了区域航磁场、航磁异常等地球物理特征;剖析了区域化探异常、区域遥感、自然重砂异常特征,进而总结了区域综合找矿信息及标志。     

内蒙古额济纳旗道噶地区土壤地球化学特征及找矿方向

内蒙古额济纳旗道噶地区矿化类型为石英脉型,见含Au石英脉出露。通过对该地区进行土壤地球化学测量工作,在统计研究区各地层Cu、Ag、Au、Pb、Zn、Sb、Mo、Ni、Co、W、As、Sb等微量元素含量基础上,应用聚类分析方法分析元素间相关关系。在研究区圈定出61处单元素异常区,其中Au元素异常8处。根据地球化学异常分类规范,综合考虑地球化学异常的规模、形态、异常的强度、分带性、异常元素的组合及异常区成矿地质条件和地球化学条件,在单元素异常的基础上圈定出乙类综合异常区2个(Ⅰ号、Ⅱ号综合异常区),丙类综合异常区1个(Ⅲ号综合异常区)。在对研究区地质特征及土壤地球化学特征的基础上圈定出3个找矿靶区,并进行地表工程验证,为进一步找矿工作提供有利依据。     

钟丘洋火山热液型铜矿床地球化学异常特征

据钟丘洋火山热液型铜矿床的地层、侵入岩、矿石和矿体中元素的分布规律,阐明了该矿床的地球化学原生异常特征;确定了与矿床有关的指示元素及其分带序列;建立了矿床剥蚀程度的评价指标及该矿床的地球化学异常模式。     

梅河口市香炉碗子金矿床地球化学特征

本文在系统搜集以往研究成果的基础上,详细归纳总结了矿床的成矿地质背景、微量元素、稀土元素、硫同位素、氢氧同位素、铅同位素的特征,进而探讨了成矿物质及成矿流体的来源。归纳总结了矿区区域1∶20万化探异常、岩石化探异常,土壤异常特征。     

金寨县汤汇地区土壤地球化学特征及找矿意义

金寨县汤汇地区位于北淮阳构造带,通过在该地区开展1 ∶ 10000 土壤地球化学测量,研究区内不同元素的地球化学异常特征.根据不同元素的地球化学性质利用因子分析确定元素在空间上的异常组合.根据元素组合中不同元素之间的异常在空间上出现的叠加现象,圈定出以Au、Ag为主的AP-1综合异常带及以Cu、Au为主的AP-3综合异...     

灌注桩中钢筋笼磁异常特征研究

灌注桩中钢筋笼由主筋、加劲筋和箍筋组成。钢筋笼长度随桩长变化,单根钢筋的长度是一定的,为了满足长桩的需要,钢筋笼常常由一节或多节焊接而成。灌注桩中的钢筋笼是一磁性体,在地磁场磁化作用下,在其周围空间分布有磁异常。钢筋笼是一个规则磁性体,本文由重磁位场的泊松公式出发,推导出钢筋笼磁异常表达式,研究了灌注桩中钢筋笼磁异常分布特征。     

高压微波消解法测定醋酸纤维过滤器采集的微尘粒子中的砷镉钴铬铜铁锰镍铅钒锌

最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提     

Shock-induced amorphous textures in plagioclase,Manicouagan, Quebec,Canada

The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events.     

A catastrophic rockslide-debris flow in Wulong, Chongqing, China in 2009: background, characterization, and causes

On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing, China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the Wulong rockslide.     

Wavelength-dispersive X-ray fluorescence spectrometric determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites

Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.     

Analysis of F, Al, Mn, Zn, Fe, Cu, Ca and Mg concentrations in brick teas from main producing areas in China

Brick-tea-type fluorosis is a peculiar endemic disease in China, which had been discovered in minority areas of western China since 1980, and distributed mainly in Tibet, Inner Mongolia, Gansu, Xinjiang, Qinghai and parts of Sichuan Province. The prevalence rate of fluorosis in Tibetan and Mongolian nationality people was higher. Epidemiological investigation showed that fluorosis morbidity and degrees were different in different brick-tea drinking areas, and it was probably caused by drinking various kinds of brick tea from different regions. Therefore, we collected 33 samples of brick tea from six provinces where minority nationalities were accustomed to drinking a large quantity of brick tea. F concentrations were determined by the combustion hydrolysis-ion selective electrode method. The results showed that among the brick teas, the F concentrations ranged from the minimum 74.1 mg/kg in Yunnan Province to the maximum 991.2 mg/kg in Sichuan Province. Besides, there was a great difference among the various kinds of brick tea, and F concentrations decreased in the order of Kang brick tea, Green brick tea, Black brick tea, Mi brick tea, Fu brick tea, Chitsu ping tea, Puerh tea, and Tuo tea. The average F concentration in brick teas was 431.92 mg/kg.     

湖北宜昌王家湾五峰组顶部Chondrites的发现及其环境意义

本文报道了湖北宜昌王家湾剖面五峰组笔石页岩段观音桥层发现的遗迹化石Chondrites的分布及其生态特点。结合生物相和同期上扬子海盆相对海平面的变化,分析了盆地水体底域在缺氧一富氧转折时期的古氧相变化特征：指出五峰组笔石页岩段上部地层沉积底域为典型的缺氧环境,在其与上覆观音桥段之间的沉积转换面附近发生了从无氧到有氧的转变,观音桥段中Hirnantia动物群繁盛于富氧的海底环境。     

Flood anticipation,reality, and uncertainty,the 2019 flood in Khuzestan,Iran

Natural Hazards - Despite the application of various methods to calculate uncertainty in flood vulnerability assessments, the challenge of uncertainty remains. The main purpose of this study was to...     

Disruption in Biogeosciences:Conceptual,Methodological,Digital,and Technological

正Over four years ago,a group of investigators came together to determine if Big Data approaches (specifically data mining,machine learning and analytics in general) might provide insight into some of the grand challenges in Earth's history:evolution of minerals,rise of oxygen,life,influence of super continental cycles,quantifying the magnitude of extinction events,and more.As a result,the team of mineralogists,petrologists,geochemists,     

Neutron-capture elements in halo, thick-disk, and thin-disk stars. Strontium, yttrium, zirconium, cerium

We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and ?2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ?40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (?2.43 ≤ [Fe/H] ≤ ?0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy’s chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component.     

Arsenic in streams,stream sediments,and ground water,fairbanks area,alaska

Arsenic concentrations of less than 5 ppb to as large as 1,260 ppb in stream waters and from 5 ppm to 4,000 ppm in stream sediments were found in the Pedro Dome-Cleary Summit area, Alaska. Waters from three of 20 wells sampled had arsenic concentrations exceeding the U.S. Public Health Service recommended limit of 50 ppb. The high arsenic levels are a consequence of arsenic enrichment in the rocks of the area. Placer and lode-gold mining may increase the arsenic content of the waters by exposing arsenic-containing rocks to surface waters and by increasing the load of arsenic-rich sediments in the streams. Finding these disturbingly large concentrations of arsenic in the waters of the Fairbanks area was the major result of this work, inasmuch as a subsequent study (to be published) revealed arsenic concentrations as large as 10 ppm in domestic wells and prompted an extensive study by Federal and State agencies of the health hazard posed by these arsenic-rich waters.