Cokriging of compositional balances including a dimension reduction and retrieval of original units

Journal of the Southern African Institute of Mining and Metallurgy
By: , and 

Links

Abstract

Compositional data constitutes a special class of quantitative measurements involving parts of a whole. The sample space has an algebraic-geometric structure different from that of real-valued data. A subcomposition is a subset of all possible parts. When compositional data values include geographical locations, they are also regionalized variables. In the Earth sciences, geochemical analyses are a common form of regionalized compositional data. Ordinarily, there are measurements only at data locations. Geostatistics has proven to be the standard for spatial estimation of regionalized variables but, in general, the compositional character of the geochemical data has been ignored. This paper presents in detail an application of cokriging for the modelling of compositional data using a method that is consistent with the compositional character of the data. The uncertainty is evaluated by a Monte Carlo procedure. The method is illustrated for the contents of arsenic and iron in groundwaters in Bangladesh, which have the peculiarity of being measured in milligrams per litre, units for which the sum of all parts does not add to a constant. Practical results include maps of estimates of the geochemical elements in the original concentration units, as well as measures of uncertainty, such as the probability that the concentration may exceed a given threshold. Results indicate that probabilities of exceedance in previous studies of the same data are too low.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Cokriging of compositional balances including a dimension reduction and retrieval of original units
Series title Journal of the Southern African Institute of Mining and Metallurgy
Volume 115
Issue 1
Year Published 2015
Language English
Publisher Southern African Institute of Mining and Metallurgy (SAIMM)
Contributing office(s) Eastern Energy Resources Science Center
Description 14 p.
First page 59
Last page 72
Google Analytic Metrics Metrics page