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Bernard Charlier Øyvind Skår Are Korneliussen Jean-Clair Duchesne Jacqueline Vander Auwera 《Contributions to Mineralogy and Petrology》2007,154(2):119-134
Major and trace element XRF and in situ LA-ICP-MS analyses of ilmenite in the Tellnes ilmenite deposit, Rogaland Anorthosite
Province, SW Norway, constrains a two stage fractional crystallization model of a ferrodioritic Fe-Ti-P rich melt. Stage 1
is characterized by ilmenite-plagioclase cumulates, partly stored in the lower part of the ore body (Lower Central Zone, LCZ),
and stage 2 by ilmenite-plagioclase-orthopyroxene-olivine cumulates (Upper Central Zone, UCZ). The concentration of V and
Cr in ilmenite, corrected for the trapped liquid effect, (1) defines the cotectic proportion of ilmenite to be 17.5 wt% during
stage 1, and (2) implies an increase of D
VIlm during stage 2, most likely related to a shift in fO2. The proportion of 17.5 wt% is lower than the modal proportion of ilmenite (ca. 50 wt%) in the ore body, implying accumulation
of ilmenite and flotation of plagioclase. The fraction of residual liquid left after crystallization of Tellnes cumulates
is estimated at 0.6 and the flotation of plagioclase at 26 wt% of the initial melt mass. The increasing content of intercumulus
magnetite with stratigraphic height, from 0 to ca. 3 wt%, results from differentiation of the trapped liquid towards magnetite
saturation. The MgO content of ilmenite (1.4–4.4 wt%) is much lower than the expected cumulus composition. It shows extensive
postcumulus re-equilibration with trapped liquid and ferromagnesian silicates, correlated with distance to the host anorthosite.
The Zr content of ilmenite, provided by in situ analyses, is low (<114 ppm) and uncorrelated with stratigraphy or Cr content.
The data demonstrate that zircon coronas observed around ilmenite formed by subsolidus exsolution of ZrO2 from ilmenite. The U-Pb zircon age of 920 ± 3 Ma probably records this exsolution process.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
23.
Laser-based validation of GLONASS orbits by short-arc technique 总被引:1,自引:0,他引:1
F. Barlier C. Berger P. Bonnefond P. Exertier O. Laurain J. F. Mangin J. M. Torre 《Journal of Geodesy》2001,75(11):600-612
The International GLONASS Experiment (IGEX-98) was carried out between 19 October 1998 and 19 April 1999. Among several objectives
was the precise orbit determination of GPS and GLONASS satellites and its validation by laser ranging observations. Local
laser-based orbit corrections (radial, tangential and normal components in a rotating orbital local reference frame) are computed
using a geometrical short-arc technique. The order of magnitude of these corrections is at the level of few decimeters, depending
on the considered components. The orbit corrections are analyzed as a function of several parameters (date, orbital plane,
geographical area). The mean corrections are at the level of several centimeters. However, when averaging over the entire
campaign and for all the satellites, no mean radial, tangential and normal orbit corrections are found. The origin of the
observed corrections is considered (errors due to the geocentric gravitational constant, the non-gravitational forces, the
thermal equilibrium of on-board equipment, the reference systems, the location and the signature of the retroreflector array,
and the precision of the satellite laser ranges). Some features are also due to errors in the radio-tracking GLONASS orbits.
Further investigations will be needed to better understand the origin of various biases.
Received: 17 February 2000 / Accepted: 31 January 2001 相似文献
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A laboratory sensor has now been developed to measure the absolute thickness of oil on water slicks. This prototype oil slick thickness measurement system is known as the laser-ultrasonic remote sensing of oil thickness (LURSOT) sensor. This laser opto-acoustic sensor is the initial step in the ultimate goal of providing an airborne sensor with the ability to remotely measure oil-on-water slick thickness. The LURSOT sensor employs three lasers to produce and measure the time-of-flight of ultrasonic waves in oil and hence provide a direct measurement of oil slick thickness. The successful application of this technology to the measurement of oil slick thickness will benefit the scientific community as a whole by providing information about the dynamics of oil slick spreading and the spill responder by providing a measurement of the effectiveness of spill countermeasures such as dispersant application and in situ burning.
This paper will provide a review of early developments and discuss the current state-of-the-art in the field of oil slick thickness measurement. 相似文献
27.
The formal stereological transformation equation for particle sieve size distribution from measurements in lower dimensional spaces is applied to laser diffractometer measurements. The transformation function for iron ore particles is measured experimentally, and modeled. The solution is tested against the measured transformation function data as well as synthetic composite distributions of the original sample. The natural size distribution of a sample taken from a grinding circuit stream was measured by a combination of standard sieving and cyclosizer, and the result is compared to the transformed size distribution calculated from laser diffractometer measurements. The stereological transformation technique performed well in all cases. 相似文献
28.
首先介绍了激光测距仪的发展历程,针对应用领域的不同,分别对3维激光成像仪和机载/星载激光测高仪的测量原理进行了阐述,并分别介绍了两种激光测距仪的工作流程以及数据处理流程,最后对两种激光测距仪的应用范围进行了阐述,并把两种激光测距技术和普通摄影测量进行了比较,指出了激光测距技术相对于普通摄影测量的优点,即高精度性、穿透性、实时性。 相似文献
29.
GPS卫星的激光测距和应用研究 总被引:2,自引:0,他引:2
简述了SLR和GPS跟踪技术的发展概况。详细介绍了近几年来对GPS-35、36卫星的激光测距进展和应用研究的情况。给出了残差分析的初步结果,并指出了目前GPS卫星的稀少的激光测距资料对卫星精密定轨和站坐标的解算是有价值的。同时,也简单地评述了GPS卫星的微波和激光跟踪技术各自的优势和弱点.建议联合利用GPS-35、36卫星的SLR和GPS观测资料来开展有关的应用研究。最后,对今后的应用研究工作提出了建议. 相似文献
30.
无内标-多外标校正激光剥蚀等离子体质谱法测定磁铁矿微量元素组成 总被引:2,自引:2,他引:2
激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)常用于磁铁矿原位微量元素分析,按照校正策略不同,主要分为内标法和无内标法。内标法需要用电子探针(EMPA)预先测定磁铁矿中内标元素Fe的含量,过程较繁琐,且待测元素含量会受到内标元素含量测定的影响。本文采用铁含量较高的玄武质玻璃BCR-2G、BIR-1G、BHVO-2G和GSE-1G作为外标,避免了内标元素含量的测定,建立了无内标-多外标校正LA-ICP-MS测定磁铁矿微量元素组成的分析方法。利用该方法测定了科马提岩玻璃GOR-128g和自然岩浆磁铁矿BC 28的微量元素组成以评估方法的可靠性。结果表明,科马提岩玻璃的测定结果与推荐值及前人内标法的测定值一致,多数元素的相对标准偏差RSD5%;自然岩浆磁铁矿的测定结果与推荐值相比,多数元素的RSD7%,低于前人内标法的RSD(15%)。由此说明无内标-多外标法可以实现富铁硅酸岩或磁铁矿微量元素含量的准确校正,克服了基体效应的影响。因此,无内标-多外标法是一种原位测定磁铁矿微量元素含量的快速、准确方法,具有一定的应用潜力。 相似文献