The role of some statistical and mathematical methods in the interpretation of regional geochemical data

Nichol, Ian; Garrett, Robert G.; Webb, John S.

doi:10.2113/gsecongeo.64.2.204

Cited by 50 publications

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“…The trend‐surface analysis is a popular technique to separate the spatial patterns into two factors: a regional trend and residual values (Agterberg, ; Davis & Sampson, ; Unwin, ). The regional trend, regarded as the geological background, is computed by the polynomial surfaces of successive powers; while the residual values, corresponding to geological anomalies, are the arithmetic differences between the original data and the regional trend, indicating local variations (Nichol et al, ).…”

Section: Methodsmentioning

confidence: 99%

Structures and Implications for Fluid Migration in the Jiadi Carlin‐Type Gold Deposit, Guizhou Province, Southwest China

et al. 2018

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The Jiadi gold deposit is a newly discovered Carlin-type gold deposit in the Guizhou Province, Southwest China. This deposit is structurally controlled by a shallow fold-fault superimposed system along the Lianhuashan trend. Field geological investigations, structural analysis, and mathematical research are conducted to study its structures and hydrothermal fluid flow process. Geological investigations (i.e. sections, stope, and drill hole) indicate that the structures are dominated by NE-trending folds, NWW-trending folds, and faults. A trend-surface analysis of the low interformational fracture zone suggests that the overall distribution of the Lianhuashan trend is controlled by the NE-trending Lianhuashan anticline. Nearly all primary Carlin-type gold deposits are distributed along the southeastern flank where the fold axis changes from NE to EW. Gold orebodies are hosted by the interformational fracture zones and primarily situated at the transitions from the high-value areas to the low-value areas of the interformational fracture zones. A stress analysis on the hydrothermal veins indicates that they are of tenso-shear properties. The ore-forming elements (Au, As, Sb, Hg, and Tl) of the hydrothermal veins from the interformational fracture zones and intrusive breccia body present strong positive anomalies compared with those from the adjacent wall rocks. According to the development patterns of the ore-forming elements and hydrothermal veins, a migration process of the ore-forming fluids is proposed: the deeply sourced ore-forming fluids migrated vertically to shallow crust along an intrusive breccia body, subsequently flowed horizontally along the interformational fracture zones accompanied by gold precipitation in the early stage, and finally migrated outward along steep microfractures during following stages.

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Section: Methodsmentioning

confidence: 99%

Structures and Implications for Fluid Migration in the Jiadi Carlin‐Type Gold Deposit, Guizhou Province, Southwest China

et al. 2018

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“…A trend map delineates the general distribution of an element, and the local variations are emphasized after the removal of systematic variations (Nichol et al, 1969). The trend surface function gives (Oliveira, 1979):…”

Section: Trend Surface Analysismentioning

confidence: 99%

A comparative study of trend surface analysis and spectrum–area multifractal model to identify geochemical anomalies

Wang

Zuo

2015

Journal of Geochemical Exploration

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“…One of its most useful applications occurs where only a few linear combinations are found to represent many variables and where these linear combinations, or factors, can be interpreted in terms of geological processes (e.g., Klovan, 1968b;Nicol et al, 1969). Even if interpretations are somewhat ambiguous, useful empirical correlations can arise in some cases (e.g., Wilson and Sinclair, 1969).…”

Section: Q-mode Factor Analysismentioning

confidence: 99%

Factor Analysis of Minor Element Data for Pyrites, Endako Molybdenum Mine, British Columbia, Canada

Dawson¹,

Sinclair²

1974

Economic Geology

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Sixty-seven pyrite samples from in and near the Endako molybdenum mine were analyzed for 11 minor elements (Ag, Ba, Bi, Co, Cu, Mn, Ni, Pb, Sn, Sr, and Zu) by quantitative emission spectrography. All elements were found to have density distributions closely approaching a log-normal model or a mixture of two log-normal populations. Studies of individual elements did not appear to provide adequate insight. into their significance. However, Q-mode factor analysis produced a threefactor model that could be integrated easily with existing geological knowledge of the deposit. These three factors account for more than 94 percent of the variance in the data. Factors 1 and 2 correlate spatially with the ore zone and a southerly pyrite zone, respectively, and are interpreted as reflecting the variable chemical nature of mineralizing fluids during high temperature (ore) metallization and lower temperature (pyrite zone) metallization, respectively. This interpretation is consistent with independent data on wall rock alteration and temperature of filling of fluid inclusions in vein quartz. Factor 3 is interpreted as a background feature relating to the host. The first three factors of an R-mode analysis correspond with Q-mode results but the overall R-mode model is less acceptable for statistical and subj,ective reasons.The results appear to have practical potential in the economic evaluation of large areas containing scattered outcrops mineralized with pyrit.e and other minerals.

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The role of some statistical and mathematical methods in the interpretation of regional geochemical data

Cited by 50 publications

References 0 publications

Structures and Implications for Fluid Migration in the Jiadi Carlin‐Type Gold Deposit, Guizhou Province, Southwest China

Structures and Implications for Fluid Migration in the Jiadi Carlin‐Type Gold Deposit, Guizhou Province, Southwest China

A comparative study of trend surface analysis and spectrum–area multifractal model to identify geochemical anomalies

Factor Analysis of Minor Element Data for Pyrites, Endako Molybdenum Mine, British Columbia, Canada

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