-Multivariate statistical analyses of geochemical, mineralogical, and cation-exchange capacity (CEC) data from a Venezuelan oil well were used to construct a model which relates elemental concentrations to mineral abundances. An r-mode factor analysis showed that most of the variance could be accounted for by four independent factors and that these factors were related to individual mineral com...

2 1. Research aims 3 2. Introduction 3 3. Materials and methods 5 3.1. Origin of samples 5 3.2. Methods 5 4. Experimental results 7 4.1. Petrographic description 7 4.2. Main petrophysical properties 7 4.3. Overall mineralogy 8 4.4. Clay minerals quantification 9 4.5. Hydromechanical behavior 10 5. Discussion 11 5.1. Identification and origin of the swelling layers 11 5.2. Influence of swelling ...

Introduction: Numerous studies at the Riotinto mining district have focused on astrobiology, sulfates and extremophilic microbial communities in the highly acidic aqueous environments [1-3]. In contrast, this project investigates past acidic alteration of nearby volcanic rocks. The present study covers a variety of alteration pathways that may influence volcanic protoliths, with the specific ty...

Many soils have clay-enriched horizons that are thought to result from pedogenic processes. Various hypotheses are proposed for expected clay size-distributions in soil profiles. The average size of clay crystallites determined by the amount of broadening of x-ray diffraction peaks ranged from 160 to >2000A 0 , but the lack of trends in four loess-de• rived soils did not permit the hypotheses t...