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Titel |
Density/area power-law models for separating multi-scale anomalies of ore and toxic elements in stream sediments in Gejiu mineral district, Yunnan Province, China |
VerfasserIn |
Q. Cheng, Q. Xia, W. Li, S. Zhang, Z. Chen, R. Zuo, W. Wang |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 7, no. 10 ; Nr. 7, no. 10 (2010-10-06), S.3019-3025 |
Datensatznummer |
250005005
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Publikation (Nr.) |
copernicus.org/bg-7-3019-2010.pdf |
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Zusammenfassung |
This contribution introduces a fractal filtering technique newly
developed on the basis of a spectral energy density vs. area power-law model
in the context of multifractal theory. It can be used to map anisotropic
singularities of geochemical landscapes created from geochemical
concentration values in various surface media such as soils, stream
sediments, tills and water. A geochemical landscape can be converted into a
Fourier domain in which the spectral energy density is plotted against the
area (in wave number units), and the relationship between the spectrum
energy density (S) and the area (A) enclosed by the above-threshold spectrum
energy density can be fitted by power-law models. Mixed geochemical
landscape patterns can be fitted with different S-A power-law models in the
frequency domain. Fractal filters can be defined according to these
different S-A models and used to decompose the geochemical patterns into
components with different self-similarities. The fractal filtering method
was applied to a geochemical dataset from 7,349 stream sediment samples
collected from Gejiu mineral district, which is famous for its word-class
tin and copper production. Anomalies in three different scales were
decomposed from total values of the trace elements As, Sn, Cu, Zn, Pb, and
Cd. These anomalies generally correspond to various geological features and
geological processes such as sedimentary rocks, intrusions, fault
intersections and mineralization. |
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