نتایج جستجو برای: geochemical survey

تعداد نتایج: 383580  

2014
Prabhu Prasad Das Hrushikesh Sahoo

Present research deals with the representative groundwater sampling locations establishment for the geochemical evaluation of the subsurface aquifer systems of Rajnagar Block, Odisha along the east coast of India. The study looks into the hydrological, topographical and geological set up of the area to evaluate the natural influencing factors and the cultural set up of the human habitats and it...

2011
Isla S. Castañeda Stefan Schouten

Molecular organic geochemical proxies are increasingly being utilized to reconstruct past environmental conditions as new tools continue to be discovered and developed. To date, organic geochemical proxies have been developed mainly for use in marine systems and are widely used in paleoceanography. In contrast, organic proxies have been less commonly used on lacustrine sedimentary records. One ...

Journal: :Journal of contaminant hydrology 2001
N Sun M Elimelech N Z Sun J N Ryan

A two-dimensional model for colloid transport in geochemically and physically heterogeneous porous media is presented. The model considers patchwise geochemical heterogeneity, which is suitable to describe the chemical variability of many surficial aquifers with ferric oxyhydroxide-coated porous matrix, as well as spatial variability of hydraulic conductivity, which results in heterogeneous flo...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Steffen Leth Jorgensen Bjarte Hannisdal Anders Lanzén Tamara Baumberger Kristin Flesland Rita Fonseca Lise Ovreås Ida H Steen Ingunn H Thorseth Rolf B Pedersen Christa Schleper

Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in geochemical composition and prokaryotic comm...

Journal: :journal of mining and environment 2015
h. shahi r. ghavami riabi a. kamkar ruhani h. asadi haroni

in this research work, the frequency domain (fd) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. in order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and blind mineralization using the surface geochemical data for the dalli cu-au porphyry deposit, a ...

2003
Dennis A. Hansell Nicholas R. Bates Donald B. Olson

The process of nitrogen fixation in the subtropical North Atlantic has received considerable study over the last few decades. The findings have highlighted a large discrepancy in estimates for the locations and rates of nitrogen fixation when results from biological techniques are compared to geochemical techniques. Here, we evaluated the distribution and rates of excess nitrate development in ...

2008
E. Galán J. C. Fernández-Caliani I. González P. Aparicio A. Romero

A collection of 235 samples were taken from 115 sites (representing a density of 1 sampling site ca. 130 km) on rural soils derived from the major rock types in the southern Iberian Massif. The geochemical baselines of selected trace elements (As, Co, Cr, Cu, Ni, Pb and Zn) were determined on the b2 mm soil fraction. The sampling sites were not directly influenced by external pollution. Soil ge...

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