نتایج جستجو برای: geochemical zonality index

تعداد نتایج: 407770  

2010
Pranab Das Sridhar D Iyer

The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB) under one class i.e., as mid-oceanic ridge basalts (MORB). Hence, a method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB). We have applied Artificial Neur...

2016
Jaana Jarva Timo Tarvainen Reijo Salminen

This study provides an overview on the development of the guidelines and legislation related to soil contamination in Finland, with the main focus on geochemical baselines. The use of geochemical baseline surveys in the assessment soil contamination in Finland and in some other countries is briefly discussed and the current practices in Finland are presented. Finally, the geochemical baselines ...

Due to the existence of a constant sum of constraints, the geochemical data is presented as the compositional data that has a closed number system. A closed number system is a dataset that includes several variables. The summation value of variables is constant, being equal to one. By calculating the correlation coefficient of a closed number system and comparing it with an open number system, ...

Abdulwahab S. Alaug Khaled A. Al-Wosabi

Organic geochemical evaluation of the Madbi Formation as the main source rock of the Al-Jawf Basin, NE Central Yemen was the main objective of this study. The organic geochemical methods used in the study include: rock-eval pyrolysis, total organic carbon, and optical measurements as the vitrinite reflectance and thermal alteration index. In this study, 67 well core and side-well core samples o...

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...

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