Evaluation of a Quality Control Monitor Material for the Routine Electron Probe Microanalysis of Kimberlite Exploration Garnets     

Deon De Bruin 《Geostandards and Geoanalytical Research》2010,34(3):257-264

Election probe microanalysis of indicator minerals is extensively used in the exploration for kimberlite deposits, the evaluation of specific kimberlite occurrences for their diamond bearing potential and to classify grains into different chemical and lithological mantle associations. Kimberlite exploration programmes can involve several tens of thousands of indicator mineral analyses. Procedures for monitoring data quality and consistency of analyses across large data sets are commonly absent. Suitable monitor minerals should be used to verify the data quality of kimberlite exploration and evaluation data sets. This material should have a suitable composition, be homogenous, be available in sufficient quantities and have a similar appearance to the unknown samples. Garnet P1, a megacryst garnet from the Premier kimberlite, was found to have a suitable composition as a monitor for kimberlite garnet analyses. Data were collected on the monitor material at regular intervals during routine analyses, over an extended period, both as a fixed grain mounted on the sample holder and as separate grains set within batches of routine samples. The data were evaluated to assess the quality and consistency in the analyses of large data sets over time. The monitor material was also analysed at independent laboratories using their routine analytical set-up and calibration procedures for comparative purposes. Values are given for the mean ± 2s range, which can serve as guide values for acceptable analyses for all elements.  相似文献   

Fossilisation of a silica diagenesis reaction front on the mid-Norwegian margin     

Raluca Cristina Neagu  Joe Cartwright  Richard Davies  Lars Jensen 《Marine and Petroleum Geology》2010

The diagenetic transformation of biogenic silica from opal-A to opal-CT was recognised on seismic reflection data over an area of 78 × 10³ km² on the mid-Norwegian margin. The opal-A/CT diagenetic boundary appears as a positive, high amplitude reflection that generally cross-cuts the hosting stratigraphy. We demonstrate that it is not a sea bottom simulating reflection (BSR) and also that is not in thermal equilibrium with the present day isotherms. We present arguments that three styles of deformation associated with the opal-A/CT reflection – polygonal faulting, regional anticlines and synclines and differential compaction folding – indicate that the silica diagenesis reaction front is fossilised at a regional scale. Isochore maps demonstrate the degree of conformity between the opal-A/CT reflection and three seismic horizons of Late Miocene to Early Pliocene age that potentially represent the paleo-seabed when ‘fossilisation’ of the reaction front took place. The seismic interpretational criteria for recognition of a fossilised diagenetic front are evaluated and the results of our study are integrated with previous studies from other basins of the NE Atlantic in order to determine if the arrest of silica diagenesis was diachronous along this continental margin.  相似文献   

Statistical and geostatistical investigations into the effects of the Gabcikovo hydropower plant on the groundwater resources of northwest Hungary / Analyses statistiques et géostatistiques des effets de la centrale hydroélectrique de Gabcikovo sur les ressources en eaux souterraines du Nord-Ouest de la Hongrie     

《水文科学杂志》2013,58(4)

Abstract

Abstract The construction of the Gabcikovo hydropower plant and the diversion of the Danube River over 25 km into an artificial channel in 1992 influenced the groundwater regime of the region considerably. Statistical and geostatistical methods are used to quantify changes of different groundwater characteristics on the Hungarian side of the river based on observations in the time period 1960–2000. External drift kriging was used to interpolate groundwater levels and the other related variables. While mean groundwater levels did not change appreciably, there are significant changes in the variability. Standard deviations of the groundwater levels and the amplitude of the annual cycle decreased near the old river bed of the Danube. The water-level fluctuations of the Danube have a decreased influence on the groundwater dynamics. Interrelationships between water levels in wells have also changed.  相似文献   

Fuzzy logic model approaches to daily pan evaporation estimation in western Turkey / Estimation de l’évaporation journalière du bac dans l’Ouest de la Turquie par des modèles à base de logique floue     

《水文科学杂志》2013,58(6)

Abstract

Abstract Evaporation is one of the fundamental elements in the hydrological cycle, which affects the yield of river basins, the capacity of reservoirs, the consumptive use of water by crops and the yield of underground supplies. In general, there are two approaches in the evaporation estimation, namely, direct and indirect. The indirect methods such as the Penman and Priestley-Taylor methods are based on meteorological variables, whereas the direct methods include the class A pan evaporation measurement as well as others such as class GGI-3000 pan and class U pan. The major difficulty in using a class A pan for the direct measurements arises because of the subsequent application of coefficients based on the measurements from a small tank to large bodies of open water. Such difficulties can be accommodated by fuzzy logic reasoning and models as alternative approaches to classical evaporation estimation formulations were applied to Lake Egirdir in the western part of Turkey. This study has three objectives: to develop fuzzy models for daily pan evaporation estimation from measured meteorological data, to compare the fuzzy models with the widely-used Penman method, and finally to evaluate the potential of fuzzy models in such applications. Among the measured meteorological variables used to implement the models of daily pan evaporation prediction are the daily observations of air and water temperatures, sunshine hours, solar radiation, air pressure, relative humidity and wind speed. Comparison of the classical and fuzzy logic models shows a better agreement between the fuzzy model estimations and measurements of daily pan evaporation than the Penman method.  相似文献   

Late glacial fans in the eastern Skagerrak; depositional environment interpreted from swath bathymetry and seismostratigraphy     

Oddvar Longva  Heidi A. Olsen  David J.W. Piper  Leif Rise  Terje Thorsnes 《Marine Geology》2008,251(1-2):110-123

The origin of acoustically transparent fan deposits overlying glacial till and ice-proximal sediments on the southern margin of the Norwegian Channel has been studied using high-resolution seismic-reflection profiles and multibeam bathymetry. The first deposits overlying glacigenic sediments are a series of stacked, acoustically transparent submarine fans. The lack of glaciomarine sediments below and between individual fans indicates that deposition was rapid and immediately followed the break up of the Late Weichselian ice cover. The fans are overlain by stratified glaciomarine sediments and Holocene mud. Because of the uniformity of this drape, the upper surface of the fan deposits is mimicked at the present seafloor, and the bathymetric images clearly show the spatial relationship of the fans to bedrock ridges and the presence of braided channel-levee systems on the surface of the youngest fans. The acoustically transparent character of the fan deposits indicates that they comprise silt and clay, and their lobate form and lack of internal stratification indicates that they were deposited by debris flows. The channel-levee morphology indicates deposition from more watery hyperconcentrated fluid flows. The fan sediments were either derived from 1) erosion of Mid Weichselian lake deposits in southern Skagerrak or 2) from Late glacial ice-margin lake deposits, ponded against the Norwegian Channel ice stream, which collapsed catastrophically when the lateral support was removed as the ice disintegrated. Fans composed almost exclusively of fine-grained sediment need not, therefore, rule out an origin in a deglacial setting relatively close to the former margins of glaciers and ice sheets.  相似文献   

Rhinocerotid tooth enamel 18O/16O variability between 23 and 12 Ma in southwestern France     

Ilhem Bentaleb  Cyril Langlois  Céline Martin  Paula Iacumin  Matthieu Carré  Pierre-Olivier Antoine  Francis Duranthon  Issam Moussa  Jean-Jacques Jaeger  Nicholas Barrett  Ron Kandorp 《Comptes Rendus Geoscience》2006,338(3):172-179

The relationship between the oxygen isotope ratio of mammal tooth enamel and that of drinking water was used to reconstruct changes in the Miocene oxygen isotope ratio of rainfall (meteoric water ${\delta }^{18}$O_MW). These, in turn, are related to climatic parameters (temperature, precipitation and evaporation rate). ${\delta }^{18}$O values of rhinocerotid teeth from the Aquitaine Basin (southwestern France) suggest a significant climatic change between 17 and 12 Ma, characterized by cooling together with precipitation increase, in agreement with other terrestrial and oceanic records. To cite this article: I. Bentaleb et al., C. R. Geoscience 338 (2006).  相似文献   

GAT磁悬浮陀螺全站仪在矿山测量中的应用     

龚云  杨志强  石震 《测绘科学》2012,37(2):185-187

GAT高精度磁悬浮陀螺全站仪是由长安大学测绘与空间信息研究所和中国航天时代电子公司共同研制开发、具有国内独立知识产权的陀螺定向仪器。GAT系列仪器采用磁悬浮吊带等技术,能无依托、自主式寻北测定目标的方位角,除架设调平及瞄准之外,整个测量过程无需手工操作,测量结束后,自动给出瞄准目标的法线与真北方位角,据此可以确定任意方向线的坐标方位角,实现定向和贯通。  相似文献   

Constructing regional advantage in non-metropolitan regions: A comparison between La Pocatière (Canada) and Tromsø (Norway)     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(3):144-154

The construction of regional advantage has recently been emphasized by scholars as a new way of increasing firms’ competitiveness in a globalizing and learning economy. This article compares the construction of regional advantage and the development paths of specific industries in two different types of non-metropolitan regions, La Pocatière in Canada and Tromsø in Norway. The authors observe a higher level of industrial dynamism in La Pocatière than in Tromsø. They find four explanations for this variation: (1) a narrower regional innovation system (RIS) in Tromsø; (2) the fact that the target industry in Tromsø (marine biotechnology) is, in general, more difficult to develop outside metropolitan regions than the diverse mechanical engineering industry found in La Pocatière; (3) a biased focus on the development of research-based knowledge and academic spin-offs in Tromsø compared with a more varied set of strategies used in La Pocatière; and (4) La Pocatière's location in proximity to the Quebec metropolitan region.  相似文献   

南京长江第四大桥索夹的定位测量     

李支彬  黄腾  康建松  刘岭 《测绘工程》2012,21(5):53-55

以南京长江第四大桥索夹放样为例,介绍该桥索夹位置计算和测量放样的基本方法和流程。分析影响悬索桥索夹放样精度的因素,并加以修正或消除,用以提高索夹放样精度。实践证明本桥索夹放样方法简单、可靠,满足设计要求。  相似文献   

超细固体悬浮液进样-电感耦合等离子体质谱法测定土壤中的微量元素   总被引：1，自引：1，他引：0  

张莉娟  徐铁民  方蓬达  魏双 《岩矿测试》2019,38(2):147-153

固体进样技术应用于土壤样品测量领域,一直受制于样品粒径的限制,无法应用在配有气动雾化器的分析仪器上。本文系统研究了土壤样品超细粉碎技术,在乙醇介质下,数分钟内将其粉碎至微米级,经此制成的固体悬浮液直接进行电感耦合等离子体质谱法(ICP-MS)测定,可以避免气动雾化器的堵塞。标准物质测定表明,样品粒径为6.8μm时,固体悬浮液进样仍然存在干扰,通过在固体悬浮液中加入少量氢氟酸和硝酸,对固体悬浮液进行改性,减小了固体悬浮液中固体颗粒粒径,从而减少了样品粒径的影响,可用ICP-MS测定土壤中锂铍钒铬镍铜锌铷锶镉铯钡铅等13个微量元素。经国家一级标准物质验证,本方法的最大相对误差在10.5%左右,多数元素的相对误差小于5%,相对标准偏差(RSD)小于5.4%(镉元素除外),满足了DZ/G 0130—2006质量控制要求。  相似文献