نتایج جستجو برای: geochemical method

تعداد نتایج: 1641388  

2012
tiMotej VerBoVŠek

Paper focuses on the analysis of geochemical data with values below the limit of detection (LOD). Such values are treated as text and are difficult to use in further calculations of mean, standard deviation and other statistical parameters. To estimate several methods for substitution of values below the LOD with fractions of LOD (zero, LOD/2, LOD/√2, LOD and no data values), a large dataset of...

Journal: :Geochemical Transactions 2006
Martin AA Schoonen Ken B Anderson Scott A Wood

Editorial Geochemical Transactions, the first online-only journal in geochemistry and environmental chemistry, is now the first major open access journal in this subject area. All issues of Geochemical Transactions, including the back content, will be fully and permanently available online to all, without a subscription charge. Copyright of all future articles will be retained by the authors. G...

2010
YAN-JIE TANG HONG-FU ZHANG JI-FENG YING

Lithium isotopes have many advantageous characteristics as geochemical tracers for a wide range of geological processes, covering fluid/melt-mineral interactions from the Earth’s surface to the mantle. The latest developments in Li isotope geochemistry, in terms of measuring techniques, major geochemical reservoirs, the contrasting behaviors during near-surface weathering, and crust/ mantle cyc...

Journal: :زمین شناسی اقتصادی 0
مهدی هاشمی گهرویی بهنام شفیعی بافتی غلامحسین شمعانیان حسین تقی زاده

in order to assess the potential of copper mineralization and its associated elements in soltan meydan basaltic formation situated in the north of shahrud, the method of stream sediment and heavy mineral has been used. to achieve this aim, totally 68 samples of sediments (-80 mesh in particle size) and 6 samples of heavy minerals (-20 mesh in particle size) have been collected in an optimized n...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده مهندسی معدن 1387

منطقه مورد مطالعه در ناحیه ایران مرکزی و در شرق استان اصفهان در زون متالوژنی خور- جندق واقع شده است. این زون دارای اندیس های شناخته شده فلزی مس، آهن، سرب، چند فلزی و همچنین غیر فلزی تالک، میکا و سنگ های قیمتی میباشد. با مطالعه اندیس های مذکور و ویژگی های کلی زون متالوژنی و زمین شناسی منطقه مدل مفهومی کانی سازی های مختلف مورد بررسی قرار گرفت. لذا هدف اصلی این تحقیق، تلفیق داده های مختلف اکتشافی ...

Journal: :iranian journal of science and technology (sciences) 2006
s. alipour

lag is a general term applied to coarse grained (> 2 mm), hard, but partially weathered rockfragments, which are concentrated at the surface through attrition of finer materials. based on morphology,mineralogy and the origin of lag from the cobar region of australia, lag may be conveniently grouped intothree broad morpho-mineralogical categories; (a) those with a rough, blocky, lithic morpholog...

2001
Qiuming CHENG

Local structural property of an image is often considered in image enhancement with various high/low pass filters. Spatial association indexes (autocorrelation, covariance, and variogram) have been commonly used to characterize the local structure of surfaces for data interpolation in kriging. Singularity is another index measuring the scaling invariant property of measures from a multifractal ...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2004
Abbas Afkhami Ali Reza Zarei

The H-point standard addition method (HPSAM), based on spectrophotometric measurements for simultaneous determination of beryllium and aluminium, is described. This method is based on the difference between their rates of reactions with Chrome Azurol S (CAS) in cetyltrimethylammonium bromide (CTAB) micellar media. The results showed that beryllium and aluminium could be determined simultaneousl...

Journal: :Geobiology 2013
J Huang X Chu T W Lyons N J Planavsky H Wen

Acanthomorphic acritarch fossils, including some interpreted to be the fossils of the earliest animal embryos, first appear in the lower Doushantuo Formation of the Yangtze Gorges area (YGA). Further, the complete paleontological and geochemical record for the YGA has played a central role in defining the global biological and geochemical backdrop that presaged and witnessed the dawn of diverse...

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