Zumlot,T., Goodell,P. and Howari,F.(2009): Geochemical mapping of New Mexico, USA, using stream sediment data. Environ. Geol., 58, 1479-1497.

『河川堆積物データを用いた米国ニューメキシコ州の地球化学図作成』


Abstract
 The spatial analysis of geochemical data has several environmental and geological applications. The present study investigated the regional distribution of Al, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, Pb, Sc, Th, Ti, U, V, and Zn elements in stream sediment samples from New Mexico State. These elements were studied in order to integrate them with geological and environmental characteristics of the area. Data are used from 27,798 samples that were originally collected during the national uranium resource evaluation (NURE) Hydrogeochemical and stream sediment reconnaissance (HSSR) program in the 1970s. The original data are available as U.S. Geological Survey Open-File Report 97-492. The study used a variety of data processing and filtering techniques that included univariate, bivariate, factor analyses and spatial analyses to transform the data into a useable format. Principal component analysis and GIS techniques are applied to classify the elements and to identify geochemical signatures, either natural or anthropogenic. The study found that the distribution of the investigated elements is mainly controlled by the bed rock chemistry. For example, along the Rio Grande rift and Jemez lineament a strong association between Co, Cr, Cu, Fe, Ni, Sc, Ti, V and Zn was observed and indicates that elements distribution in the area controlled by the mafic factor. The rare earth elements (REE) factor which is consists of Ce, La and U, also has strong, localized, clusters in the felsic centers in New Mexico.

Keywords: Geochemical mapping; Stream sediments; Principal component analysis; GIS; New Mexico, USA』

Introduction
Statement of the problem
Study area
Dataset
Methodology
 Detection and removal of outlier
 Test for normality
 Data set classification
 Multivarient analyses
Results
 Univarient analysis
 Bivariant analysis
 Spatial analysis
 Spatial distribution of factor scores
 Median value rock chemistry for New Mexico
Discussion
Future work
Conclusions
References


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