Textural and genetic relationships between glauconite and celadonite at the nanoscale: two different structural-compositional fields

Abstract. Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of Betic Cordillera (southern Spain) as a result microbial activity. Samples from limit between two micas, recognizable scanning electron microscopy, have been extracted using focussed ion beam technique studied by high-resolution analytical microscopy. Both micas are present randomly oriented differentiated small crystals boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg K. At lattice scale, shows high degree order, homogeneous orientation visible parameters being difference glauconite, formed packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, accordance X-ray diffractograms which indicate that is mica–smectite interstratification 90 % mica layers. The gap indicates not endmember glauconitic series represent different structural tendencies mica, having distorted octahedral sheets, indicated systematically higher b celadonite.