Multivariate Statistical Analysis of Phyllite Samples Based on Chemical (XRF) and Mineralogical Data by XRD

Abstract

It is presented the results obtained of a multivariate statistical analysis concerning the chemical and phase composition, as a characterization purpose, carried out with 52 rock phyllite samples selected from the provinces of Almería and Granada (SE Spain). Chemical analysis was performed by X-ray fluorescence (XRF). Crystalline phase analysis was performed by X-ray powder diffraction (XRD) and the mineralogical composition was then deduced. Quantification of weight loss (100˚ and 1000˚C) was carried out by thermal analysis. The aims of this investigation were to analyze and compare the chemical and mineralogical composition of all these samples and to find similarities and differences between them to allow a classification. Several correlations between results of the characterization techniques have been also investigated. All the data have been processed using the multivariate statistical analysis method. The XRF macroelements (10) and microelements (39) data generate one macrogroup with two new subgroups (1 and 2), and an isolated sample. In subgroup 1 of macroelements, a positive correlation was found between XRF results and geographic location characterized by lower MgO content, which is associated to its geological origins. When multivariate statistical analysis is applied to results obtained by XRD, two groups appear: the first one with a sample with zero percentage of iron oxide and the second one with the rest of the samples, which is classified in two groups. A correlation is observed between the alkaline content (XRF) and illite (XRD), CaO and MgO with dolomite and indirectly between the weight loss after heating at 1000˚C and the contents of phase minerals that lose structural water (illite + chlorite) or carbon dioxide (dolomite). The present investigation has interest and implications for geochemistry and analytical chemistry concerning earth rocks and silicate raw materials.

Correlation between chemical and mineralogical characteristics and permeability of phyllite clays using multivariate statistical analysis

“…The results of the chemical analyses by XRF in the 52 phyllite samples have been previously reported (Garzón et al, 2009a(Garzón et al, , 2009bGarzón et al, 2010;Garzón et al, 2012). The chemical composition demonstrated a predominance of silica (maximum66.61wt.% in sample 45) and alumina (maximum 27.32 wt.% in sample 5), with variable content of iron oxides (maximum 8.99 wt.% in sample 11), calcium oxide (maximum14.24wt.% in sample 6) and other minor components ( Table 1).…”

“…The analysis of permeability values in the range of small pores (0.17-25 nm) revealed separate samples 6, 14, and 23, which had the highest degree of permeability, while sample 6 for instance had the lowest proportion of SiO2, as well as highest quantities of CaO (Table 1). Furthermore, sample 23 was included in a mineralogical differentiated subgroup, as shown in Garzón et al (2012).…”

“…In this study, a total of 52 phyllite clay samples from several deposits in Almería and Granada provinces (Andalusia Region, Spain) were studied. The identification, description, and their GPS location of all these samples have previously been reported (Garzón et al, 2009b;Garzón et al, 2012). Fig.…”

Late Holocene high precipitation events recorded in lake sediments and catchment geomorphology, Lake Vuoksjávrátje, NW Sweden

“…Owing to their local presence and weak particle cohesion (Garzón et al . ), phyllites are a likely source of clay‐ and silt‐sized material within the till blanket and ultimately, in the lake sediments. The uncomplicated lake configuration suggests a simple sediment distribution pattern.…”

Mineralogy and organic geochemistry of phyllite from the Dewon–Pokrzywna deposit, the Opava Mountains (SW Poland)

“…De spite rather sim ple min er al ogy, the vari abil ity of both chem i cal com po si tion and pro por tions of rock-form ing min er als in phyllite sam ples even from the same lo cal ity can be quite high (Garzón et al, 2012(Garzón et al, , 2016. There fore, the de tailed knowledge of phyllite min er al ogy is pre req ui site for con sid er ing those rocks as a can di date for buffer or back fill ma te rial.…”