thumbnail

Estimation of the geochemical threshold and its statistical significance

Journal of Geochemical Exploration

By:

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

A statistic is proposed for estimating the geochemical threshold and its statistical significance, or it may be used to identify a group of extreme values that can be tested for significance by other means. The statistic is the maximum gap between adjacent values in an ordered array after each gap has been adjusted for the expected frequency. The values in the ordered array are geochemical values transformed by either ln(?? - ??) or ln(?? - ??) and then standardized so that the mean is zero and the variance is unity. The expected frequency is taken from a fitted normal curve with unit area. The midpoint of an adjusted gap that exceeds the corresponding critical value may be taken as an estimate of the geochemical threshold, and the associated probability indicates the likelihood that the threshold separates two geochemical populations. The adjusted gap test may fail to identify threshold values if the variation tends to be continuous from background values to the higher values that reflect mineralized ground. However, the test will serve to identify other anomalies that may be too subtle to have been noted by other means. ?? 1981.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Estimation of the geochemical threshold and its statistical significance
Series title:
Journal of Geochemical Exploration
Volume
16
Issue:
1
Year Published:
1981
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geochemical Exploration
First page:
49
Last page:
76
Number of Pages:
28