نتایج جستجو برای: geochemical unit
تعداد نتایج: 406665 فیلتر نتایج به سال:
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...
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 ...
Geochemical background is the basis of anomaly evaluation in mineral exploration and environmental investigation. However, value obtained from secondary media inevitably affected by weathering, transportation, sorting, which leads to depletion or enrichment chemical elements. This problem can be avoided geochemical mapping exposed crust. In this paper, more than 38,000 samples rocks data were c...
Abstract Most conventional statistical methods aiming at defining geochemical concentration thresholds for separating anomalies from background have limited effectiveness in areas with complex geological settings and variable lithology. In this paper, median+2MAD as a method of exploratory data analysis (EDA) and concentration-area (C-A) fractal model as two effective approaches in separation g...
The Bundelkhand-Aravalli craton is the most important lithotectonic unit in the central and western India where Paleoproterozoic Aravalli Supracrustal sequence has been deposited over an Archaean basement, the latter also known as the Banded Gneiss Complex (BGC). A NE-trending linear metasedimentary sequence, designated as the Jahazpur Belt occurs along the eastern fringe of the Aravalli Superg...
A comparison is made of the probability of the process of two neutrino double beta decay for Se in direct (counter) and geochemical experiments. It is shown that the probability is systematically lower in geochemical experiments, which characterize the probability of ββ(2ν) decay a few billions years ago. The experimental data for Te are also analyzed. It is shown that geochemical measurements ...
The Basalt of Summit Creek is an enigmatic basalt unit that is about 55 million years (Ma) in age, located south of Mount Rainier. These basalts formed in a transitional time between the formation of the Coastal Range Basalts and the present Cascade arc. Through geochemical and paleomagnetic techniques, samples were collected and analyzed. Paleomagnetic samples showed nearly complete post erupt...
Geochemical mapping programs carried out by the Geological Survey of Sweden (SGU) have generated large databases containing information on the concentrations of chemical elements in rocks, surface sediments and biogeochemical materials. Regional geochemical data being imprecise, multivariate, spatially auto-correlated and non-normally distributed pose specific problems to the choice of data ana...
Compositional time series are formed from measurements of proportions that sum to one in each period of time. We might be interested in forecasting the proportion of home loans that have adjustable rates, the proportion of nonagricultural jobs in manufacturing, the proportion of a specific oxide in the geochemical composition of a rock, or the proportion of an election betting market choosing a...
Temporal gaps in the stratigraphic record have important implications for the interpretation of stratigraphically rapid geochemical and paleobiologic changes, for the development of high-resolution time scales (e.g., orbital time scales), and for deciphering the response of depositional systems to climatic change and basin evolution (e.g., accommodation space vs. sediment supply). In ancient pe...
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