This paper is designed to provide the reader with some guidelines towards understanding the importance of the log-ratio approach in geochemistry. An application example is presented with an analysis of the water chemistry from the Arno river basin (Tuscany, central Italy). Simple graphical alternatives are proposed using ilr (isometric log-ratio) transformation on compositional data (constrained support), which are generally used to build up molar-ratio diagrams. If the variables are suitably chosen from a geochemical standpoint, relationships among samples in space and time, as well as compositional changes attributable to different natural or anthropogenic processes, can be analysed on a sound statistical basis. Classical statistics can be applied to ilr diagrams to evaluate differences among groups of data, presence of outliers, or significant changes in time (monitoring). The final aim is to demonstrate that through simple principles of univariate or bivariate statistics, valuable results can be obtained, both from a geochemical and a statistical point of view. The approach can be extended to the analysis of different geochemical data matrices.

Isometric log-ratio co-ordinates and their simple use in water geochemistry / A. Buccianti. - In: BOLETIN GEOLOGICO Y MINERO. - ISSN 0366-0176. - STAMPA. - 122(4):(2011), pp. 453-458.

Isometric log-ratio co-ordinates and their simple use in water geochemistry

BUCCIANTI, ANTONELLA
2011

Abstract

This paper is designed to provide the reader with some guidelines towards understanding the importance of the log-ratio approach in geochemistry. An application example is presented with an analysis of the water chemistry from the Arno river basin (Tuscany, central Italy). Simple graphical alternatives are proposed using ilr (isometric log-ratio) transformation on compositional data (constrained support), which are generally used to build up molar-ratio diagrams. If the variables are suitably chosen from a geochemical standpoint, relationships among samples in space and time, as well as compositional changes attributable to different natural or anthropogenic processes, can be analysed on a sound statistical basis. Classical statistics can be applied to ilr diagrams to evaluate differences among groups of data, presence of outliers, or significant changes in time (monitoring). The final aim is to demonstrate that through simple principles of univariate or bivariate statistics, valuable results can be obtained, both from a geochemical and a statistical point of view. The approach can be extended to the analysis of different geochemical data matrices.
2011
122(4)
453
458
A. Buccianti
File in questo prodotto:
File Dimensione Formato  
6_ARTICULO 3.pdf

Accesso chiuso

Tipologia: Versione finale referata (Postprint, Accepted manuscript)
Licenza: Tutti i diritti riservati
Dimensione 550.27 kB
Formato Adobe PDF
550.27 kB Adobe PDF   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/553060
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? ND
social impact