Microstructures of deformed calcite in marble from the Bergell Alps are studied by using a microfocused polychromatic synchrotron X-ray beam. The high spatial resolution, together with orientation and strain resolutions, reveals twin plane orientation, multiple twin lamellae, and strain distributions associated with the twins. Single and multiple mechanical twins on e 1⁄4 0118 systems are confi...

Mechanical twins are common microstructures in deformed calcite. Calcite have been used for a long time as indicators of stress/strain orientations and magnitudes. Developments during the last decade point toward significant improvements existing techniques well new applications calcite twin analysis tectonic studies. This review summarises recent progress understanding formation, including nuc...

wide compared with the length of the specimen, and so is the angle between the lateral edge of the kink band and the axis of extension, E = [sin xo/sin (xi + so) ] 1. (2) For narrow kink bands and deformation bands, (a) an approximate relation is s = cot (900 w); (b) a more precise relation where a and ,3 are the respective angles between the kink-band boundary and the active glide plane in the...

During phase transitions the ordering of cations and/or anions along specific crystallographic directions can take place. As a result, extra reflections may occur in diffraction patterns, which indicate cell doubling and reduction symmetry. However, similar features also arise from twinning. Here nanostructures glendonite, calcite (CaCO3) pseudomorph after ikaite (CaCO3·6H2O), Victoria Cave (Ru...

The substrate effect of mica and hematite on the nucleation and crystallization of calcite was investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD) methods. On mica, we found, in the absence of Mg2+, the substrates’ (001) surfaces with hexagonal and pseudo-hexagonal two-dimensional (2-D) structure can affect the orientation ...

Through the production and export of their calcite coccoliths, coccolithophores form a key component of the global carbon cycle. Despite this key role, very little is known about the biogeochemical role of different coccolithophore species in terms of calcite production, and how these species will respond to future climate change and ocean acidification. Here, we present the first study to esti...

Recent solubility, electrokinetic, spectroscopic and flotation studies in our laboratory on apatite and calcite in aqueous electrolytes indicate complex mineral_olution interactions which can alter surface characteristics of these minerals markedly in the presence of each other. In the case of systems containing such sparingly soluble minerals, understanding of the mineral_olution chemical equi...