Sr and Pb isotopic composition of five USGS glasses (BHVO-2G, BIR-1G, BCR-2G, TB-1G, NKT-1G)

Sr isotopic compositions and Rb / Sr ratios of three USGS glasses (BHVO-2G, BIR-1G, BCR-2G) are identical to those of the original USGS reference materials. NKT-1G and TB-1G give values of 0.70351 and 0.70558, respectively. Pb isotopic ratios were measured by the standard-sample bracketing technique on an MC-ICP-MS, which give results that are comparable in accuracy and reproducibility to double spike analyses. However, assessment of the reproducibility of the technique is hampered by inhomogeneous contamination of all USGS reference materials analysed. This contamination is likely to be the reason why the USGS glasses do not all have the same Pb isotopic composition as their unfused originals. Powdered glasses, distributed for characterisation of the glasses by bulk analytical techniques, do not all have the same Pb isotopic compositions as the solid glass material, and can therefore not be used for this purpose.     

地学数据网络共享与交换研究的新进展——IAMG2006相关议题论文评述

国际数学地质协会2006年会(IAMG2006)于2006年9月在加拿大多伦多召开。大会主题为“基于多源数据的定量地学”,共分14个分会场,其中第5分会场“通过开放式网络标准传递和发布地学信息”围绕国际地科联地学信息应用与管理委员会所组织的GeoSciML研究展开。通过现场交流和对论文的分析,本文重点介绍了GeoSciML研究的基本情况和最新研究进展。     

用最小绝对偏差方法(LAD)估计极值分布参数的探讨

数理统计问题中的最小绝对偏差方法(Least Absolute Deviation)由于具有良好的稳健性,近年来备受重视。本文所研究的是如何将最小绝对偏差法及非线性回归模型相结合,应用于极值分布的参数估计,并与经典的参数估计法相比较。通过对徐州市降雨量数据的研究表明,改进后的参数估计法不仅提高了模型拟和的精确度,而且有良好的稳定性,可以推广到相关气象要素的预测、预报研究中。其中,将LAD法运用于极值分布模型是一个新的尝试。     

氟化物环境容量的研究

由高斯烟羽模式推导出的标准浓度分布推算源强分布的反演模式方法,计算了西宁市北郊地区环境空气中氟化物的环境容量。计算结果表明:拟建或已经在生产的各铝厂氟化物排放量均不超过按城市标准计算出的环境容量值,但均超过按农业区标准计算出的环境容量值。为了保护该地区农业生态环境,需要对现有的各铝厂氟化物排放量进行削减。     

Assessment of liquefaction and lateral spreading on the shore of Lake Sapanca during the Kocaeli (Turkey) earthquake

The 1999 Kocaeli earthquake of Turkey (M_w = 7.4) caused great destruction to buildings, bridges and other facilities, and a death tall of about 20,000. During this earthquake, severe damages due to soil liquefaction and associated ground deformations also occurred widespread in the eastern Marmara Region of Turkey. Soil liquefaction was commonly observed along the shorelines. One of these typical sites is Sapanca town founded on the shore of Lake Sapanca. This study was undertaken as quantitative measurement of ground deformations induced by liquefaction along the southern shore of Lake Sapanca. The permanent lateral ground deformation was measured through the aerial photogrammetry technique at several locations both along the shoreline and in the town. In situ soil profiles and material properties at Sapanca area were obtained based on the data from 55 borings and standard penetration tests (SPT), and laboratory tests, respectively. The data and the empirical methods recommended by an NCEER workshop were employed to evaluate the liquefaction resistance of the soils. In addition, simple shaking tests on a limited number of samples were also performed. The permanent ground displacements were estimated from the existing empirical models, sliding block method and residual visco-elastic finite element methods. Then these estimations were compared with the observed ground displacements. The assessments suggested that liquefaction at Sapanca have occurred within Quaternary alluvial fan deposits at depths 1 and 14 m, and the major regions of liquefaction and associated ground deformations were located along the shore and creeks. The evaluations also indicated that for sites with no sand boils but with ground displacement greater than 1 m, thickness of the non-liquefiable layer was large. It is also noted that no liquefaction-induced ground surface disruption is expected at the site when the thickness of the liquefiable and non-liquefiable layers vary between 0.5 and 1.5 m, and 3.5 and 5.5 m, respectively. Except one model, all the empirical models employed in the study over-predicted the observed lateral ground displacements, while sliding block method and residual visco-elastic finite element methods yielded reasonably good results if the known properties of liquefied soils are used.     

Phosphate sorption desorption characteristics of some ferruginous soils of tropical region in Eastern India

Phosphate sorption and desorption experiments were conducted with four ferruginous soils (alfisols) of Eastern India, in view of the low native phosphate concentrations in tropical Indian soils. From the P-isotherm curve, standard P requirement (SPR) of the soils was determined. Phosphate sorption data were fitted to both Langmuir and Freundlich equations and mean sorption maximum values obtained for the different soil series were in the decreasing order as Matimahal > Anandapur > Mrigindih > Kashipur. The fraction of added P sorbed followed the same trend as SPR, P sorption maximum (P_max), phosphate affinity constant (K), maximum phosphate buffering capacity (MPBC), Freundlich constant K′ and phosphate desorption values. Phosphate sorption maximum was significantly correlated with MPBC, Freundlich 1/n, SPR, clay and different forms of Fe and Al. The value of K (bonding energy) was significantly correlated with MPBC, Freundlich K′ and pyrophosphate extractable Fe and Al. The MPBC was significantly correlated with Freundlich K′, Freundlich constant 1/n, clay, oxalate and dithionite extractable, amorphous and crystalline form of Fe and Al. Freundlich K′ was significantly correlated with Freundlich 1/n, pH_water, clay, dithionite extractable and crystalline form of Fe and Al. The results suggested that the soils having higher amount of extractable and reactive Fe and Al shared higher P sorbtion capacity and such soils may need higher levels of P application     

基于上海数字化台网的地震记录探讨西部地区地震定位

东部地区的数字化地震台网在定位西部地区的某些地震时总产生偏差,这一现象很普遍。本文利用中国地震局2001~2003年测定的中国西部地区(云南、四川、甘肃、青海、新疆、内蒙古)地震,比较上海数字地震台网的大震速报结果,对上海数字地震台网在地震定位方面存在的一些问题进行分析与处理,进而加深速报人员对西部地区地震记录特点的理解,提高东部地区的地震分析人员对西部地震的速报精度。     

对地质勘查组织“产品”设计的理解

从讨论ISO 9000:2000标准“设计和开发”的定义出发,对地质勘查组织的的产品、产品质量特性和产品的设计进行了讨论,提出了地质勘查组织产品设计与标准中规定的设计和开发的概念以及对应关系,并对标准中的“设计和开发”与地质勘查组织“设计与开发”的内容进行了对比分析。     

广东省各地市耕地面积统计偏差分析

深入分析耕地面积详查数据与统计数据的来源和计量单位口径以数据覆盖范围,建立了详查口径耕地面积与统计口径耕地面积的关系方程。根据1996年详查耕地面积计算了广东省21个地市实际的统计口径耕地面积,并与各地上报的1996年统计耕地面积比较。结果表明,人为夸大或虚报耕地面积情况主要出现的珠江三角洲经济区内,大多数山区地市这一迹象并不明显。     

长江三峡链子崖危岩体防治工程中的锚固钻孔工艺

介绍了长江三峡链子崖危岩体的概况以及整治危岩体中造锚索孔的技术,包括钻机在高空排架固定、防止孔斜及测斜、破碎带和大裂缝的钻进技术,以及大裂缝的堵漏技术。